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Sample records for t2 weighted magnetic

  1. Signs of patellar chondromalacia on sagittal T2-weighted magnetic resonance imaging

    International Nuclear Information System (INIS)

    De Smet, A.A.; Monu, J.U.; Fisher, D.R.; Keene, J.S.; Graf, B.K.

    1992-01-01

    We incidentally noted distinctive high signal defects or fissures in the patellar articular cartilage on sagittal T2-weighted magnetic resonance (MR) images in 4 patients. At subsequent arthroscopy all 4 patients were found to have patellar chondromalacia. To determine the reliabilty of these signs, we retrospectively evaluated, in a blinded manner, sagittal T2-weighted MR images of the knee in 75 patients who were undergoing arthroscopic assessment of their patellar articular cartilage. We indentified high signal defects of fissures in the patellar cartilage of 5 patients. Patellar chondromalacia was noted at arthroscopy in all 5 patients. Arthroscopy demonstrated patellar chondromalacia in an additional 21 patients with normal MR images. We conclude that high signal defects or fissures on sagittal T2-weighted images are usefull signs of patellar chondromalacia. This single imaging sequence will, however, detect only a small number of the cartilage lesions that may be present. (orig.)

  2. Signs of patellar chondromalacia on sagittal T2-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    De Smet, A.A.; Monu, J.U.; Fisher, D.R. (Univ. of Wisconsin Hospital and Clinics, Dept. of Radiology, Madison, WI (United States)); Keene, J.S.; Graf, B.K. (Univ. of Wisconsin Hospital and Clinics, Div. of Orthopedic Surgery, Madison, WI (United States))

    1992-02-01

    We incidentally noted distinctive high signal defects or fissures in the patellar articular cartilage on sagittal T2-weighted magnetic resonance (MR) images in 4 patients. At subsequent arthroscopy all 4 patients were found to have patellar chondromalacia. To determine the reliabilty of these signs, we retrospectively evaluated, in a blinded manner, sagittal T2-weighted MR images of the knee in 75 patients who were undergoing arthroscopic assessment of their patellar articular cartilage. We indentified high signal defects of fissures in the patellar cartilage of 5 patients. Patellar chondromalacia was noted at arthroscopy in all 5 patients. Arthroscopy demonstrated patellar chondromalacia in an additional 21 patients with normal MR images. We conclude that high signal defects or fissures on sagittal T2-weighted images are usefull signs of patellar chondromalacia. This single imaging sequence will, however, detect only a small number of the cartilage lesions that may be present. (orig.).

  3. Assessment of T2-Weighted Coronal Magnetic Resonance Images in the Investigation of Pituitary Lesions

    International Nuclear Information System (INIS)

    Yuksekkaya, Ruken; Aggunlu, Levent; Oner, Yusuf; Celik, Halil; Akpek, Sergin; Celikyay, Fatih

    2014-01-01

    Magnetic resonance imaging is the most important diagnostic method in the investigation of the pituitary lesions. Our aim is to determine whether T2-weighted coronal images may be helpful in the evaluation of the pituitary gland with suspected pituitary adenomas. One hundred and sixty-seven patients were examined prospectively with T2-weighted coronal and T1-weighted coronal images enhanced with intravenous contrast material. The images were evaluated for the presence, the size, the location, and the ancillary signs including sellar floor erosion or ballooning, infindibulary deviation, convexity of the superior border of the gland, diffuse enlargement of the gland, and the invasion of the cavenous sinuses on both images. In forty-six (28%) patients lesions were revealed on both sequences. In twenty-one (12%) patients the lesions that were revealed on the T1-weighted images were not detected on the T2-weighted images. Positive predictive value, negative predictive value, sensitivity, specificity, and diagnostic accuracy rates of T2-weighted coronal images on the detection of the presence of lesions were 100%, 17.4%, 68.7%, 100%, and 87.4%, respectively. Both T2-weighted coronal and T1-weighted coronal images enhanced with intravenous gadolinium-based contrast material are important in the diagnosis of pituitary adenomas. T2-weighted coronal images could be used as a screening tool for the primary evaluation of the pituitary gland

  4. Magnetization transfer on T2-weighted image : magnetization Transfer ratios in normal brain and cerebral lesions

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    Lim, Myung Kwan; Roh, Hong Gee; Suh, Chang Hae; Cho, Young Kook; Kim, Hyung Jin; Kim, Jin Hee; Kim, Sung Tae; Choi, Sung Kyu [Inha Univ. College of Medicine, Incheon (Korea, Republic of)

    1998-07-01

    To evaluate the magnetization transfer ratio(MTR) of various normal structures and pathologic lesions, as seen on magnetization transfer T2-weighted images (MT+T2WI). Materials and Methods : In ten normal volunteers, T2-weighted images without MT (MT-T2WI) and with MT(MT+T2WI) were obtained. Off-set pulses used in MT+T2WI were 400, 600, 1000, 1500, and 2000Hz. In 60 clinical cases infarction(n=10), brain tumors(n=5), traumatic hematomas(n=5), other hematomas(n=3) vascular malformation(n=2) white matter disease(n=2) normal(n=31) and others(n=2), both MT-T2WI and MT+T2WI images were obtained using an off-set pulse of 600 Hz. In all volunteers and patients, MTR in various normal brain parenchyma and abnormal areas was measured. Results : The MTRs of white and gray matter were 48% and 45% respectively at 400 Hz, 26% and 22% at 600Hz, 12% and 11% of 1000Hz, 10% and 9% 1500HZ, and 9% and 8% at 2000Hz of RF. The MTR of CSF was 43% at 400 Hz of off-resonance RF, while the contrast resolution of T2WI was poor. An off-resonance of 600Hz appeared to be the optimal frequency. In diseased areas,MTRs varied but were usually similar to or lower than those of brain parenchyma. Conclusion : The optimal off-resonance RF on MT+T2WI appears to be 600 Hz for relatively high MTR of brain parenchyma and low MTR of CSF,in which MTRs of white and gray matter were 26% and 22%, respectively, of 600Hz off-set pulse. The MTRs of cerebral lesions varied and further studies of various cerebral lesions are needed.

  5. Three-dimensional isotropic T2-weighted cervical MRI at 3 T: Comparison with two-dimensional T2-weighted sequences

    International Nuclear Information System (INIS)

    Kwon, J.W.; Yoon, Y.C.; Choi, S.-H.

    2012-01-01

    Aim: To compare three-dimensional (3D) isotropic T2-weighted magnetic resonance imaging (MRI) sequences and reformation with two-dimensional (2D) T2-weighted sequences regarding image quality of the cervical spine at 3 T. Materials and methods: A phantom study was performed using a water-filled cylinder. The signal-to-noise and image homogeneity were evaluated. Fourteen (n = 14) volunteers were examined at 3 T using 3D isotropic T2-weighted sagittal and conventional 2D T2-weighted sagittal, axial, and oblique sagittal MRI. Multiplanar reformation (MPR) of the 3D T2-weighted sagittal dataset was performed simultaneously with image evaluation. In addition to artefact assessment, the visibility of anatomical structures in the 3D and 2D sequences was qualitatively assessed by two radiologists independently. Cohen’s kappa and Wilcoxon signed rank test were used for the statistical analysis. Result: The 3D isotropic T2-weighted sequence resulted in the highest signal-to-noise ratio (SNR) and lowest non-uniformity (NU) among the sequences in the phantom study. Quantitative evaluation revealed lower NU values of the cerebrospinal fluid (CSF) and muscles in 2D T2-weighted sagittal sequences compared to the 3D volume isotropic turbo spin-echo acquisition (VISTA) sequence. The other NU values revealed no statistically significant difference between the 2D turbo spin-echo (TSE) and 3D VISTA sequences (0.059 < p < 0.959). 3D VISTA images showed significantly fewer CSF flow artefacts (p < 0.001) and better delineated intradural nerve rootlets (p = 0.001) and neural foramina (p = 0.016) compared to 2D sequences. Conclusion: A 3D T2 weighted sequence is superior to conventional 2D sequences for the delineation of intradural nerve rootlets and neural foramina and is less affected by CSF flow artefacts.

  6. High incidence of microbleeds in hemodialysis patients detected by T2*-weighted gradient-echo magnetic resonance imaging

    International Nuclear Information System (INIS)

    Yokoyama, Shunichi; Uomizu, Kenji; Kajiya, Yoriko; Tajitsu, Kenichiro; Kusumoto, Kazuhiro; Hirano, Hirofumi

    2005-01-01

    The incidence and characteristics of microbleeds in hemodialysis (HD) patients were investigated to elucidate the clinical significance with T 2 * -weighted gradient-echo magnetic resonance (MR) imaging. The 57 patients with chronic renal failure maintained by HD had no previous history of stroke. The control group consisted of 53 patients without previous history of stroke or chronic renal failure. The incidence and the number of microbleeds were assessed in the HD and control groups. The findings of microbleeds with T 2 * -weighted gradient-echo MR imaging were compared with those of T 1 - and T 2 -weighted MR imaging in HD patients. The incidence of microbleeds was significantly greater in the HD patients compared with the control patients. T 2 * -weighted gradient-echo imaging revealed a total of 44 microbleeds in 11 HD patients. T 2 -weighted imaging demonstrated 13 of 44 microbleeds as hyperintensity, whereas T 1 -weighted imaging demonstrated 12 lesions as hypointensity. T 2 - and T 1 -weighted imagings did not demonstrate any findings in 31 and 32 lesions, respectively. T 2 * -weighted gradient-echo MR imaging is effective to detect microbleeds which may be a predictor of intracerebral hemorrhage in HD patients and should be included in the protocol for the study of cerebrovascular disease, because T 2 - and T 1 -weighted MR imaging recognizes microbleeds as lacunar infarction. (author)

  7. Stability of polyelectrolyte-coated iron nanoparticles for T2-weighted magnetic resonance imaging

    Science.gov (United States)

    McGrath, Andrew J.; Dolan, Ciaran; Cheong, Soshan; Herman, David A. J.; Naysmith, Briar; Zong, Fangrong; Galvosas, Petrik; Farrand, Kathryn J.; Hermans, Ian F.; Brimble, Margaret; Williams, David E.; Jin, Jianyong; Tilley, Richard D.

    2017-10-01

    Iron nanoparticles are highly-effective magnetic nanoparticles for T2 magnetic resonance imaging (MRI). However, the stability of their magnetic properties is dependent on good protection of the iron core from oxidation in aqueous media. Here we report the synthesis of custom-synthesized phosphonate-grafted polyelectrolytes (PolyM3) of various chain lengths, for efficient coating of iron nanoparticles with a native iron oxide shell. The size of the nanoparticle-polyelectrolyte assemblies was investigated by transmission electron microscopy and dynamic light scattering, while surface attachment was confirmed by Fourier transform infrared spectroscopy. Low cytotoxicity was observed for each of the nanoparticle-polyelectrolyte ("Fe-PolyM3") assemblies, with good cell viability (>80%) remaining up to 100 μg mL-1 Fe in HeLa cells. When applied in T2-weighted MRI, corresponding T2 relaxivities (r2) of the Fe-PolyM3 assemblies were found to be dependent on the chain length of the polyelectrolyte. A significant increase in contrast was observed when polyelectrolyte chain length was increased from 6 to 65 repeating units, implying a critical chain length required for stabilization of the α-Fe nanoparticle core.

  8. Image quality and cancer visibility of T2-weighted Magnetic Resonance Imaging of the prostate at 7 Tesla

    NARCIS (Netherlands)

    Vos, E.K.; Lagemaat, M.W.; Barentsz, J.O.; Futterer, J.J.; Zamecnik, P.; Roozen, H.; Orzada, S.; Bitz, A.K.; Maas, M.C.; Scheenen, T.W.J.

    2014-01-01

    To assess the image quality of T2-weighted (T2w) magnetic resonance imaging of the prostate and the visibility of prostate cancer at 7 Tesla (T).Seventeen prostate cancer patients underwent T2w imaging at 7T with only an external transmit/receive array coil. Three radiologists independently scored

  9. Myometrial invasion and overall staging of endometrial carcinoma: assessment using fusion of T2-weighted magnetic resonance imaging and diffusion-weighted magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Guo Y

    2017-12-01

    Full Text Available Yu Guo,1,2 Ping Wang,2 Penghui Wang,2 Wei Gao,1 Fenge Li,3 Xueling Yang,1 Hongyan Ni,2 Wen Shen,2 Zhi Guo1 1Department of Interventional Therapy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin’s Clinical Research Center for Cancer, Tianjin, 2Department of Radiology, Tianjin First Center Hospital, The First Central Clinical College of Tianjin Medical University, Tianjin, 3Department of Gynecology, Tianjin First Center Hospital, Tianjin, People’s Republic of China Background: The age of onset of endometrial carcinoma has been decreasing in recent years. In endometrial carcinoma, it is important to accurately assess invasion depth and preoperative staging. Fusion of T2-weighted magnetic resonance imaging (T2WI and diffusion-weighted magnetic resonance imaging (DWI may contribute to the improvement of anatomical localization of lesions.Materials and methods: In our study, a total of 58 endometrial carcinoma cases were included. Based on the revised 2009 International Federation of Gynecology and Obstetrics staging system, a fusion of T2WI and DWI was utilized for the evaluation of invasion depth and determination of the overall stage. Postoperative pathologic assessment was considered as the reference standard. The consistency of T2WI image staging and pathologic staging, and the consistency of fused T2WI and DWI and pathologic staging were all analyzed using Kappa statistics.Results: Compared with the T2WI group, a significantly higher diagnostic accuracy was observed for myometrial invasion with fusion of T2WI and DWI (77.6% for T2WI; 94.8% for T2WI-DWI. For the identification of deep invasion, we calculated values for diagnostic sensitivity (69.2% for T2WI; 92.3% for T2WI-DWI, specificity (80% for T2WI; 95.6% for T2WI-DWI, positive predictive value (50% for T2WI; 85.7% for T2WI-DWI, and negative predictive value (90% for

  10. T2-Weighted 4D Magnetic Resonance Imaging for Application in Magnetic Resonance–Guided Radiotherapy Treatment Planning

    Science.gov (United States)

    Freedman, Joshua N.; Collins, David J.; Bainbridge, Hannah; Rank, Christopher M.; Nill, Simeon; Kachelrieß, Marc; Oelfke, Uwe; Leach, Martin O.; Wetscherek, Andreas

    2017-01-01

    Objectives The aim of this study was to develop and verify a method to obtain good temporal resolution T2-weighted 4-dimensional (4D-T2w) magnetic resonance imaging (MRI) by using motion information from T1-weighted 4D (4D-T1w) MRI, to support treatment planning in MR-guided radiotherapy. Materials and Methods Ten patients with primary non–small cell lung cancer were scanned at 1.5 T axially with a volumetric T2-weighted turbo spin echo sequence gated to exhalation and a volumetric T1-weighted stack-of-stars spoiled gradient echo sequence with golden angle spacing acquired in free breathing. From the latter, 20 respiratory phases were reconstructed using the recently developed 4D joint MoCo-HDTV algorithm based on the self-gating signal obtained from the k-space center. Motion vector fields describing the respiratory cycle were obtained by deformable image registration between the respiratory phases and projected onto the T2-weighted image volume. The resulting 4D-T2w volumes were verified against the 4D-T1w volumes: an edge-detection method was used to measure the diaphragm positions; the locations of anatomical landmarks delineated by a radiation oncologist were compared and normalized mutual information was calculated to evaluate volumetric image similarity. Results High-resolution 4D-T2w MRI was obtained. Respiratory motion was preserved on calculated 4D-T2w MRI, with median diaphragm positions being consistent with less than 6.6 mm (2 voxels) for all patients and less than 3.3 mm (1 voxel) for 9 of 10 patients. Geometrical positions were coherent between 4D-T1w and 4D-T2w MRI as Euclidean distances between all corresponding anatomical landmarks agreed to within 7.6 mm (Euclidean distance of 2 voxels) and were below 3.8 mm (Euclidean distance of 1 voxel) for 355 of 470 pairs of anatomical landmarks. Volumetric image similarity was commensurate between 4D-T1w and 4D-T2w MRI, as mean percentage differences in normalized mutual information (calculated over all

  11. T2-Weighted 4D Magnetic Resonance Imaging for Application in Magnetic Resonance-Guided Radiotherapy Treatment Planning.

    Science.gov (United States)

    Freedman, Joshua N; Collins, David J; Bainbridge, Hannah; Rank, Christopher M; Nill, Simeon; Kachelrieß, Marc; Oelfke, Uwe; Leach, Martin O; Wetscherek, Andreas

    2017-10-01

    The aim of this study was to develop and verify a method to obtain good temporal resolution T2-weighted 4-dimensional (4D-T2w) magnetic resonance imaging (MRI) by using motion information from T1-weighted 4D (4D-T1w) MRI, to support treatment planning in MR-guided radiotherapy. Ten patients with primary non-small cell lung cancer were scanned at 1.5 T axially with a volumetric T2-weighted turbo spin echo sequence gated to exhalation and a volumetric T1-weighted stack-of-stars spoiled gradient echo sequence with golden angle spacing acquired in free breathing. From the latter, 20 respiratory phases were reconstructed using the recently developed 4D joint MoCo-HDTV algorithm based on the self-gating signal obtained from the k-space center. Motion vector fields describing the respiratory cycle were obtained by deformable image registration between the respiratory phases and projected onto the T2-weighted image volume. The resulting 4D-T2w volumes were verified against the 4D-T1w volumes: an edge-detection method was used to measure the diaphragm positions; the locations of anatomical landmarks delineated by a radiation oncologist were compared and normalized mutual information was calculated to evaluate volumetric image similarity. High-resolution 4D-T2w MRI was obtained. Respiratory motion was preserved on calculated 4D-T2w MRI, with median diaphragm positions being consistent with less than 6.6 mm (2 voxels) for all patients and less than 3.3 mm (1 voxel) for 9 of 10 patients. Geometrical positions were coherent between 4D-T1w and 4D-T2w MRI as Euclidean distances between all corresponding anatomical landmarks agreed to within 7.6 mm (Euclidean distance of 2 voxels) and were below 3.8 mm (Euclidean distance of 1 voxel) for 355 of 470 pairs of anatomical landmarks. Volumetric image similarity was commensurate between 4D-T1w and 4D-T2w MRI, as mean percentage differences in normalized mutual information (calculated over all respiratory phases and patients), between

  12. Methods of fetal MR: beyond T2-weighted imaging

    International Nuclear Information System (INIS)

    Brugger, Peter C.; Stuhr, Fritz; Lindner, Christian; Prayer, Daniela

    2006-01-01

    The present work reviews the basic methods of performing fetal magnetic resonance imaging (MRI). Since fetal MRI differs in many respects from a postnatal study, several factors have to be taken into account to achieve satisfying image quality. Image quality depends on adequate positioning of the pregnant woman in the magnet, use of appropriate coils and the selection of sequences. Ultrafast T2-weighted sequences are regarded as the mainstay of fetal MR-imaging. However, additional sequences, such as T1-weighted images, diffusion-weighted images, echoplanar imaging may provide further information, especially in extra- central-nervous system regions of the fetal body

  13. Methods of fetal MR: beyond T2-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Brugger, Peter C. [Center of Anatomy and Cell Biology, Integrative Morphology Group, Medical University of Vienna, Waehringerstrasse 13, 1090 Vienna (Austria)]. E-mail: peter.brugger@meduniwien.ac.at; Stuhr, Fritz [Department of Radiology, Medical University of Vienna, Waehringerguertel 18-20, 1090 Vienna (Austria); Lindner, Christian [Department of Radiology, Medical University of Vienna, Waehringerguertel 18-20, 1090 Vienna (Austria); Prayer, Daniela [Department of Radiology, Medical University of Vienna, Waehringerguertel 18-20, 1090 Vienna (Austria)

    2006-02-15

    The present work reviews the basic methods of performing fetal magnetic resonance imaging (MRI). Since fetal MRI differs in many respects from a postnatal study, several factors have to be taken into account to achieve satisfying image quality. Image quality depends on adequate positioning of the pregnant woman in the magnet, use of appropriate coils and the selection of sequences. Ultrafast T2-weighted sequences are regarded as the mainstay of fetal MR-imaging. However, additional sequences, such as T1-weighted images, diffusion-weighted images, echoplanar imaging may provide further information, especially in extra- central-nervous system regions of the fetal body.

  14. T2*-weighted image/T2-weighted image fusion in postimplant dosimetry of prostate brachytherapy

    International Nuclear Information System (INIS)

    Katayama, Norihisa; Takemoto, Mitsuhiro; Yoshio, Kotaro

    2011-01-01

    Computed tomography (CT)/magnetic resonance imaging (MRI) fusion is considered to be the best method for postimplant dosimetry of permanent prostate brachytherapy; however, it is inconvenient and costly. In T2 * -weighted image (T2 * -WI), seeds can be easily detected without the use of an intravenous contrast material. We present a novel method for postimplant dosimetry using T2 * -WI/T2-weighted image (T2-WI) fusion. We compared the outcomes of T2 * -WI/T2-WI fusion-based and CT/T2-WI fusion-based postimplant dosimetry. Between April 2008 and July 2009, 50 consecutive prostate cancer patients underwent brachytherapy. All the patients were treated with 144 Gy of brachytherapy alone. Dose-volume histogram (DVH) parameters (prostate D90, prostate V100, prostate V150, urethral D10, and rectal D2cc) were prospectively compared between T2 * -WI/T2-WI fusion-based and CT/T2-WI fusion-based dosimetry. All the DVH parameters estimated by T2 * -WI/T2-WI fusion-based dosimetry strongly correlated to those estimated by CT/T2-WI fusion-based dosimetry (0.77≤ R ≤0.91). No significant difference was observed in these parameters between the two methods, except for prostate V150 (p=0.04). These results show that T2 * -WI/T2-WI fusion-based dosimetry is comparable or superior to MRI-based dosimetry as previously reported, because no intravenous contrast material is required. For some patients, rather large differences were observed in the value between the 2 methods. We thought these large differences were a result of seed miscounts in T2 * -WI and shifts in fusion. Improving the image quality of T2 * -WI and the image acquisition speed of T2 * -WI and T2-WI may decrease seed miscounts and fusion shifts. Therefore, in the future, T2 * -WI/T2-WI fusion may be more useful for postimplant dosimetry of prostate brachytherapy. (author)

  15. Histological evaluation of lung cancer with T2-weighted magnetic resonance images

    International Nuclear Information System (INIS)

    Ohta, Takashi; Matsuura, Yoshifumi; Shioya, Sumie; Ohta, Yasuyo

    1995-01-01

    We investigated the differences in signal intensity of lung cancer tissue and non-cancerous lung tissues on T 2 -weighted magnetic resonance (MR) images. MR images were obtained from patients with squamous cell carcinoma (n=6), adenocarcinoma (n=5), small cell carcinoma (n=5), and large cell carcinoma (n=1). To compare the MR signal intensity between tissues, we calculated the signal intensity ratios for tumor/skeletal muscle and lung/skeletal muscle. The MR signal intensity for each tissue was measured with a densitometer and T 2 -weighted MR images with a similar window and a center. The value of the signal intensity ratio for squamous cell carcinoma (3.26±0.76) was greater than those for adenocarcinoma (1.99±0.50, p<0.05), small cell carcinoma (2.35±0.60), large cell carcinoma (2.46), and non-cancerous lung tissues (1.70±0.68, p<0.02). The values of the MR signal intensity ratio for non-cancerous lung tissues were 2.00 for a collapsed lung, 0.93 for a fibrotic lung, and 2.18 for a fibrotic lung with obstructive pneumonia. The results suggest that the MR signal intensity ratio for pathologic tissues/normal skeletal muscle can be a useful indicator for qualitative and quantitative MR imaging diagnosis. (author)

  16. Semi-automatic segmentation of myocardium at risk in T2-weighted cardiovascular magnetic resonance.

    Science.gov (United States)

    Sjögren, Jane; Ubachs, Joey F A; Engblom, Henrik; Carlsson, Marcus; Arheden, Håkan; Heiberg, Einar

    2012-01-31

    T2-weighted cardiovascular magnetic resonance (CMR) has been shown to be a promising technique for determination of ischemic myocardium, referred to as myocardium at risk (MaR), after an acute coronary event. Quantification of MaR in T2-weighted CMR has been proposed to be performed by manual delineation or the threshold methods of two standard deviations from remote (2SD), full width half maximum intensity (FWHM) or Otsu. However, manual delineation is subjective and threshold methods have inherent limitations related to threshold definition and lack of a priori information about cardiac anatomy and physiology. Therefore, the aim of this study was to develop an automatic segmentation algorithm for quantification of MaR using anatomical a priori information. Forty-seven patients with first-time acute ST-elevation myocardial infarction underwent T2-weighted CMR within 1 week after admission. Endocardial and epicardial borders of the left ventricle, as well as the hyper enhanced MaR regions were manually delineated by experienced observers and used as reference method. A new automatic segmentation algorithm, called Segment MaR, defines the MaR region as the continuous region most probable of being MaR, by estimating the intensities of normal myocardium and MaR with an expectation maximization algorithm and restricting the MaR region by an a priori model of the maximal extent for the user defined culprit artery. The segmentation by Segment MaR was compared against inter observer variability of manual delineation and the threshold methods of 2SD, FWHM and Otsu. MaR was 32.9 ± 10.9% of left ventricular mass (LVM) when assessed by the reference observer and 31.0 ± 8.8% of LVM assessed by Segment MaR. The bias and correlation was, -1.9 ± 6.4% of LVM, R = 0.81 (p Segment MaR, -2.3 ± 4.9%, R = 0.91 (p Segment MaR and manually assessed MaR in T2-weighted CMR. Thus, the proposed algorithm seems to be a promising, objective method for standardized MaR quantification in T2

  17. Semi-automatic segmentation of myocardium at risk in T2-weighted cardiovascular magnetic resonance

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    Sjögren Jane

    2012-01-01

    Full Text Available Abstract Background T2-weighted cardiovascular magnetic resonance (CMR has been shown to be a promising technique for determination of ischemic myocardium, referred to as myocardium at risk (MaR, after an acute coronary event. Quantification of MaR in T2-weighted CMR has been proposed to be performed by manual delineation or the threshold methods of two standard deviations from remote (2SD, full width half maximum intensity (FWHM or Otsu. However, manual delineation is subjective and threshold methods have inherent limitations related to threshold definition and lack of a priori information about cardiac anatomy and physiology. Therefore, the aim of this study was to develop an automatic segmentation algorithm for quantification of MaR using anatomical a priori information. Methods Forty-seven patients with first-time acute ST-elevation myocardial infarction underwent T2-weighted CMR within 1 week after admission. Endocardial and epicardial borders of the left ventricle, as well as the hyper enhanced MaR regions were manually delineated by experienced observers and used as reference method. A new automatic segmentation algorithm, called Segment MaR, defines the MaR region as the continuous region most probable of being MaR, by estimating the intensities of normal myocardium and MaR with an expectation maximization algorithm and restricting the MaR region by an a priori model of the maximal extent for the user defined culprit artery. The segmentation by Segment MaR was compared against inter observer variability of manual delineation and the threshold methods of 2SD, FWHM and Otsu. Results MaR was 32.9 ± 10.9% of left ventricular mass (LVM when assessed by the reference observer and 31.0 ± 8.8% of LVM assessed by Segment MaR. The bias and correlation was, -1.9 ± 6.4% of LVM, R = 0.81 (p Conclusions There is a good agreement between automatic Segment MaR and manually assessed MaR in T2-weighted CMR. Thus, the proposed algorithm seems to be a

  18. Intensity of prolactinoma on T2-weighted magnetic resonance imaging: towards another gender difference

    International Nuclear Information System (INIS)

    Kreutz, Julie; Vroonen, Laurent; Petrossians, Patrick; Rostomyan, Liliya; Beckers, Albert; Cattin, Francoise; Thiry, Albert; Tshibanda, Luaba; Bonneville, Jean-Francois

    2015-01-01

    Clinical presentations of prolactinomas are quite different between genders. In comparison with women's prolactinoma, those in men showed predominance of large tumors with high prolactin (PRL) levels. This preponderance could be attributed to a greater proliferative potential of the tumors. Differences in magnetic resonance imaging (MRI) signal at diagnosis have not been yet clearly evaluated. We conduct a retrospective study comparing MRI signal intensity (SI) on T2-weighted images (T2-WI) between 41 men and 41 women to investigate whether or not men prolactinoma present specific features. In addition to the size of the adenoma and PRL levels (P < 0001), prolactinomas in men also exhibit differences from those in women in signal on T2-WI on MRI (P < 0001). Women's prolactinomas are mostly of high SI on T2-WI while men's prolactinomas exhibit a more heterogeneous pattern of SI on T2-WI. Prolactinomas presenting with low SI on T2-WI are almost exclusively encountered in men. Presence of T2-WI hypointensities in pituitary adenoma can be predictive of a different subtype of prolactinoma almost encountered in men and possibly translate the presence of spherical amyloid deposits, in agreement with the literature. (orig.)

  19. Intensity of prolactinoma on T2-weighted magnetic resonance imaging: towards another gender difference

    Energy Technology Data Exchange (ETDEWEB)

    Kreutz, Julie [University Hospital Sart-Tilman, Department of Radiology, Liege (Belgium); Centre Hospitalier Universitaire de Liege, Domaine Universitaire du Sart Tilman, Service d' Imagerie Medicale, Liege (Belgium); Vroonen, Laurent; Petrossians, Patrick; Rostomyan, Liliya; Beckers, Albert [University Hospital Sart-Tilman, Department of Endocrinology, Liege (Belgium); Cattin, Francoise [University Hospital Besancon, Department of Radiology, Besancon (France); Thiry, Albert [University Hospital Sart-Tilman, Department of Pathology, Liege (Belgium); Tshibanda, Luaba [University Hospital Sart-Tilman, Department of Radiology, Liege (Belgium); Bonneville, Jean-Francois [University Hospital Sart-Tilman, Department of Radiology, Liege (Belgium); University Hospital Sart-Tilman, Department of Endocrinology, Liege (Belgium)

    2015-07-15

    Clinical presentations of prolactinomas are quite different between genders. In comparison with women's prolactinoma, those in men showed predominance of large tumors with high prolactin (PRL) levels. This preponderance could be attributed to a greater proliferative potential of the tumors. Differences in magnetic resonance imaging (MRI) signal at diagnosis have not been yet clearly evaluated. We conduct a retrospective study comparing MRI signal intensity (SI) on T2-weighted images (T2-WI) between 41 men and 41 women to investigate whether or not men prolactinoma present specific features. In addition to the size of the adenoma and PRL levels (P < 0001), prolactinomas in men also exhibit differences from those in women in signal on T2-WI on MRI (P < 0001). Women's prolactinomas are mostly of high SI on T2-WI while men's prolactinomas exhibit a more heterogeneous pattern of SI on T2-WI. Prolactinomas presenting with low SI on T2-WI are almost exclusively encountered in men. Presence of T2-WI hypointensities in pituitary adenoma can be predictive of a different subtype of prolactinoma almost encountered in men and possibly translate the presence of spherical amyloid deposits, in agreement with the literature. (orig.)

  20. Evaluation of the Subscapularis Tendon Tears on 3T Magnetic Resonance Arthrography: Comparison of Diagnostic Performance of T1-Weighted Spectral Presaturation with Inversion-Recovery and T2-Weighted Turbo Spin-Echo Sequences.

    Science.gov (United States)

    Lee, Hoseok; Ahn, Joong Mo; Kang, Yusuhn; Oh, Joo Han; Lee, Eugene; Lee, Joon Woo; Kang, Heung Sik

    2018-01-01

    To compare the T1-weighted spectral presaturation with inversion-recovery sequences (T1 SPIR) with T2-weighted turbo spin-echo sequences (T2 TSE) on 3T magnetic resonance arthrography (MRA) in the evaluation of the subscapularis (SSC) tendon tear with arthroscopic findings as the reference standard. This retrospective study included 120 consecutive patients who had undergone MRA within 3 months between April and December 2015. Two musculoskeletal radiologists blinded to the arthroscopic results evaluated T1 SPIR and T2 TSE images in separate sessions for the integrity of the SSC tendon, examining normal/articular-surface partial-thickness tear (PTTa)/full-thickness tear (FTT). Diagnostic performance of T1 SPIR and T2 TSE was calculated with arthroscopic results as the reference standard, and sensitivity, specificity, and accuracy were compared using the McNemar test. Interobserver agreement was measured with kappa (κ) statistics. There were 74 SSC tendon tears (36 PTTa and 38 FTT) confirmed by arthroscopy. Significant differences were found in the sensitivity and accuracy between T1 SPIR and T2 TSE using the McNemar test, with respective rates of 95.9-94.6% vs. 71.6-75.7% and 90.8-91.7% vs. 79.2-83.3% for detecting tear; 55.3% vs. 31.6-34.2% and 85.8% vs. 78.3-79.2%, respectively, for FTT; and 91.7-97.2% vs. 58.3-61.1% and 89% vs. 78-79.3%, respectively, for PTTa. Interobserver agreement for T1 SPIR was almost perfect for T1 SPIR (κ = 0.839) and substantial for T2 TSE (κ = 0.769). T1-weighted spectral presaturation with inversion-recovery sequences is more sensitive and accurate compared to T2 TSE in detecting SSC tendon tear on 3T MRA.

  1. Optimization of T2-weighted imaging for shoulder magnetic resonance arthrography by synthetic magnetic resonance imaging.

    Science.gov (United States)

    Lee, Seung Hyun; Lee, Young Han; Hahn, Seok; Yang, Jaemoon; Song, Ho-Taek; Suh, Jin-Suck

    2017-01-01

    Background Synthetic magnetic resonance imaging (MRI) allows reformatting of various synthetic images by adjustment of scanning parameters such as repetition time (TR) and echo time (TE). Optimized MR images can be reformatted from T1, T2, and proton density (PD) values to achieve maximum tissue contrast between joint fluid and adjacent soft tissue. Purpose To demonstrate the method for optimization of TR and TE by synthetic MRI and to validate the optimized images by comparison with conventional shoulder MR arthrography (MRA) images. Material and Methods Thirty-seven shoulder MRA images acquired by synthetic MRI were retrospectively evaluated for PD, T1, and T2 values at the joint fluid and glenoid labrum. Differences in signal intensity between the fluid and labrum were observed between TR of 500-6000 ms and TE of 80-300 ms in T2-weighted (T2W) images. Conventional T2W and synthetic images were analyzed for diagnostic agreement of supraspinatus tendon abnormalities (kappa statistics) and image quality scores (one-way analysis of variance with post-hoc analysis). Results Optimized mean values of TR and TE were 2724.7 ± 1634.7 and 80.1 ± 0.4, respectively. Diagnostic agreement for supraspinatus tendon abnormalities between conventional and synthetic MR images was excellent (κ = 0.882). The mean image quality score of the joint space in optimized synthetic images was significantly higher compared with those in conventional and synthetic images (2.861 ± 0.351 vs. 2.556 ± 0.607 vs. 2.750 ± 0.439; P optimized TR and TE for shoulder MRA enables optimization of soft-tissue contrast.

  2. Automatic Mapping Extraction from Multiecho T2-Star Weighted Magnetic Resonance Images for Improving Morphological Evaluations in Human Brain

    Directory of Open Access Journals (Sweden)

    Shaode Yu

    2013-01-01

    Full Text Available Mapping extraction is useful in medical image analysis. Similarity coefficient mapping (SCM replaced signal response to time course in tissue similarity mapping with signal response to TE changes in multiecho T2-star weighted magnetic resonance imaging without contrast agent. Since different tissues are with different sensitivities to reference signals, a new algorithm is proposed by adding a sensitivity index to SCM. It generates two mappings. One measures relative signal strength (SSM and the other depicts fluctuation magnitude (FMM. Meanwhile, the new method is adaptive to generate a proper reference signal by maximizing the sum of contrast index (CI from SSM and FMM without manual delineation. Based on four groups of images from multiecho T2-star weighted magnetic resonance imaging, the capacity of SSM and FMM in enhancing image contrast and morphological evaluation is validated. Average contrast improvement index (CII of SSM is 1.57, 1.38, 1.34, and 1.41. Average CII of FMM is 2.42, 2.30, 2.24, and 2.35. Visual analysis of regions of interest demonstrates that SSM and FMM show better morphological structures than original images, T2-star mapping and SCM. These extracted mappings can be further applied in information fusion, signal investigation, and tissue segmentation.

  3. Image quality and cancer visibility of T2-weighted Magnetic Resonance Imaging of the prostate at 7 Tesla

    International Nuclear Information System (INIS)

    Vos, E.K.; Lagemaat, M.W.; Barentsz, J.O.; Fuetterer, J.J.; Zamecnik, P.; Roozen, H.; Maas, M.C.; Orzada, S.; Bitz, A.K.; Scheenen, T.W.J.

    2014-01-01

    To assess the image quality of T2-weighted (T2w) magnetic resonance imaging of the prostate and the visibility of prostate cancer at 7 Tesla (T). Seventeen prostate cancer patients underwent T2w imaging at 7T with only an external transmit/receive array coil. Three radiologists independently scored images for image quality, visibility of anatomical structures, and presence of artefacts. Krippendorff's alpha and weighted kappa statistics were used to assess inter-observer agreement. Visibility of prostate cancer lesions was assessed by directly linking the T2w images to the confirmed location of prostate cancer on histopathology. T2w imaging at 7T was achievable with 'satisfactory' (3/5) to 'good' (4/5) quality. Visibility of anatomical structures was predominantly scored as 'satisfactory' (3/5) and 'good' (4/5). If artefacts were present, they were mostly motion artefacts and, to a lesser extent, aliasing artefacts and noise. Krippendorff's analysis revealed an α = 0.44 between three readers for the overall image quality scores. Clinically significant cancer lesions in both peripheral zone and transition zone were visible at 7T. T2w imaging with satisfactory to good quality can be routinely acquired, and cancer lesions were visible in patients with prostate cancer at 7T using only an external transmit/receive body array coil. (orig.)

  4. Comparison between T2*- and T2-weighted images in diagnosing rotator cuff tears

    International Nuclear Information System (INIS)

    Kumagai, Hideo; Ito, Hisao; Kubo, Atsushi.

    1995-01-01

    This study was performed to determine the merits of T2 * -weighted images in diagnosing rotator cuff tear, compared with T2-weighted images. T2- and T2 * -weighted images were obtained in 10 asymptomatic volunteers and 94 patients with symptoms referable to the rotator cuff. The increased signal with full thickness of the rotator cuff was not shown on either T2- or T2 * -weighted images in the volunteers. These findings on T2-weighted images and on T2 * -weighted images were observed in 33 and 58 of 94 patients with symptoms, respectively. Every patient who showed these abnormal findings on T2-weighted images had the abnormal findings on T2 * -weighted images. These findings on T2 * -weighted images were wider than those on T2-weighted images in 20 of 33 patients. Surgical findings were available in 21 of 94 patients. Rotator cuff tears were surgically confirmed in 20 patients whose MR images showed increased signal lesions on both T2- and T2 * -weighted images. On the other hand, one patient who did not have rotator cuff tear showed increased signal lesion with full thickness on T2 * -weighted images, but not on T2-weighted images. We think increased signal lesions on T2-weighted images may strongly suggest rotator cuff tear, whereas those on T2 * -weighted images are not specific. (author)

  5. Contrast-enhanced Magnetic Resonance Imaging of Pelvic Bone Metastases at 3.0 T: Comparison Between 3-dimensional T1-weighted CAIPIRINHA-VIBE Sequence and 2-dimensional T1-weighted Turbo Spin-Echo Sequence.

    Science.gov (United States)

    Yoon, Min A; Hong, Suk-Joo; Lee, Kyu-Chong; Lee, Chang Hee

    2018-06-12

    This study aimed to compare 3-dimensional T1-weighted gradient-echo sequence (CAIPIRINHA-volumetric interpolated breath-hold examination [VIBE]) with 2-dimensional T1-weighted turbo spin-echo sequence for contrast-enhanced magnetic resonance imaging (MRI) of pelvic bone metastases at 3.0 T. Thirty-one contrast-enhanced MRIs of pelvic bone metastases were included. Two contrast-enhanced sequences were evaluated for the following parameters: overall image quality, sharpness of pelvic bone, iliac vessel clarity, artifact severity, and conspicuity and edge sharpness of the smallest metastases. Quantitative analysis was performed by calculating signal-to-noise ratio and contrast-to-noise ratio of the smallest metastases. Significant differences between the 2 sequences were assessed. CAIPIRINHA-VIBE had higher scores for overall image quality, pelvic bone sharpness, iliac vessel clarity, and edge sharpness of the metastatic lesions, and had less artifacts (all P 0.05). Our results suggest that CAIPIRINHA-VIBE may be superior to turbo spin-echo for contrast-enhanced MRI of pelvic bone metastases at 3.0 T.

  6. High-Quality T2-Weighted 4-Dimensional Magnetic Resonance Imaging for Radiation Therapy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Du, Dongsu [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Caruthers, Shelton D. [Philips Healthcare, Cleveland, Ohio (United States); Glide-Hurst, Carri [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Low, Daniel A. [Department of Radiation Oncology, University of California-Los Angeles, Los Angeles, California (United States); Li, H. Harold; Mutic, Sasa [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Hu, Yanle, E-mail: Hu.Yanle@mayo.edu [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Department of Radiation Oncology, Mayo Clinic in Arizona, Phoenix, Arizona (United States)

    2015-06-01

    Purpose: The purpose of this study was to improve triggering efficiency of the prospective respiratory amplitude-triggered 4-dimensional magnetic resonance imaging (4DMRI) method and to develop a 4DMRI imaging protocol that could offer T2 weighting for better tumor visualization, good spatial coverage and spatial resolution, and respiratory motion sampling within a reasonable amount of time for radiation therapy applications. Methods and Materials: The respiratory state splitting (RSS) and multi-shot acquisition (MSA) methods were analytically compared and validated in a simulation study by using the respiratory signals from 10 healthy human subjects. The RSS method was more effective in improving triggering efficiency. It was implemented in prospective respiratory amplitude-triggered 4DMRI. 4DMRI image datasets were acquired from 5 healthy human subjects. Liver motion was estimated using the acquired 4DMRI image datasets. Results: The simulation study showed the RSS method was more effective for improving triggering efficiency than the MSA method. The average reductions in 4DMRI acquisition times were 36% and 10% for the RSS and MSA methods, respectively. The human subject study showed that T2-weighted 4DMRI with 10 respiratory states, 60 slices at a spatial resolution of 1.5 × 1.5 × 3.0 mm{sup 3} could be acquired in 9 to 18 minutes, depending on the individual's breath pattern. Based on the acquired 4DMRI image datasets, the ranges of peak-to-peak liver displacements among 5 human subjects were 9.0 to 12.9 mm, 2.5 to 3.9 mm, and 0.5 to 2.3 mm in superior-inferior, anterior-posterior, and left-right directions, respectively. Conclusions: We demonstrated that with the RSS method, it was feasible to acquire high-quality T2-weighted 4DMRI within a reasonable amount of time for radiation therapy applications.

  7. Diffusion-weighted magnetic resonance imaging combined with T2-weighted images in the detection of small breast cancer: a single-center multi-observer study.

    Science.gov (United States)

    Wu, Lian-Ming; Chen, Jie; Hu, Jiani; Gu, Hai-Yan; Xu, Jian-Rong; Hua, Jia

    2014-02-01

    Breast cancer is the most common cancer in women worldwide. However, it remains a difficult diagnosis problem to differentiate between benign and malignant breast lesions, especially in small early breast lesions. To assess the diagnostic value of diffusion-weighted imaging (DWI) combined with T2-weighted imaging (T2WI) for small breast cancer characterization. Fifty-eight patients (65 lesions) with a lesion breast magnetic resonance imaging (MRI) including DWI and histological analysis. Three observers with varying experience levels reviewed MRI. The probability of breast cancer in each lesion on MR images was recorded with a 5-point scale. Areas under the receiver-operating characteristic curve (AUCs) were compared by using the Z test; sensitivity and specificity were determined with the Z test after adjusting for data clustering. AUC of T2WI and DWI (Observer 1, 0.95; Observer 2, 0.91; Observer 3, 0.83) was greater than that of T2WI (Observer 1, 0.80; Observer 2, 0.74; Observer 3, 0.70) for all observers (P breast cancer characterization. It should be considered selectively in the preoperative evaluation of patients with small lesions of the breast.

  8. MR imaging findings of diffuse axonal injury: comparison of T2-weighted gradient images and T1- and T2-weighted spin-echo images

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seo Young; Lee, Ghi Jai; Kim, Jeong Seok; Shim, Jae Chan; Kim, Ho Kyun [Inje Univ. College of Medicine, Seoul (Korea, Republic of)

    1998-10-01

    To compare T2-weighted images with spin-echo T1- and turbo spin-echo (TSE) T2-weighted images in patients with diffuse axonal injury(DAI). Using a 1.0T MR unit, SE T1-, TSE T2-, and and FLASH T2-weighted images were obtained from 69 patients with a history of head trauma. In 18MR images of 17 patients with imaging findings of DAI, T2-weighted images were retrospectively compared with SE T1- and TSE T2-weighted images. The interval between trauma and MR scan varied from 5 days to 24(mean, 11) months. Focusing on the number of lesions, and their location and signal intensity, as weel as associated findings, three images were simultaueously evaluated. In 18 MR images of 17 patients with MR imaging findings of DAI, 21 lesions were detected on T1-weighted images, 28 on TSE T2-weighted images, and 70 on T2-weighted images;the last of these revealed all lesions detected on the other two. Most lesions were hypointense on T1-weighted images(17/21), hyperintense on TSE T2-weighted (21/28), and hypointense on T2-weighted (63/70). Common locations for DAI were the frontal lobe (n=3D35) and corpus callosum (n=3D22). Associated brain injuries were cortical contusion (n=3D5), brainstem injury (n=3D3), deep gray matter injury (n=3D2), and subdural hematoma(n=3D1). In patients with DAI. T2-weighted images can detect more lesions and associated petechial hemorrhage than can TSE T2-weighted images. This modality is thus useful for the evaluation of patients with head trauma.=20.

  9. Non-contrast magnetic resonance imaging for bladder cancer: fused high b value diffusion-weighted imaging and T2-weighted imaging helps evaluate depth of invasion

    International Nuclear Information System (INIS)

    Lee, Minsu; Oh, Young Taik; Jung, Dae Chul; Park, Sung Yoon; Shin, Su-Jin; Cho, Nam Hoon; Choi, Young Deuk

    2017-01-01

    To investigate the utility of fused high b value diffusion-weighted imaging (DWI) and T2-weighted imaging (T2WI) for evaluating depth of invasion in bladder cancer. We included 62 patients with magnetic resonance imaging (MRI) and surgically confirmed urothelial carcinoma in the urinary bladder. An experienced genitourinary radiologist analysed the depth of invasion (T stage <2 or ≥2) using T2WI, DWI, T2WI plus DWI, and fused DWI and T2WI (fusion MRI). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were investigated. Area under the curve (AUC) was analysed to identify T stage ≥2. The rate of patients with surgically confirmed T stage ≥2 was 41.9% (26/62). Sensitivity, specificity, PPV, NPV and accuracy were 50.0%, 55.6%, 44.8%, 60.6% and 53.2%, respectively, with T2WI; 57.7%, 77.8%, 65.2%, 71.8% and 69.4%, respectively, with DWI; 65.4%, 80.6%, 70.8%, 76.3% and 74.2%, respectively, with T2WI plus DWI and 80.8%, 77.8%, 72.4%, 84.9% and 79.0%, respectively, with fusion MRI. AUC was 0.528 with T2WI, 0.677 with DWI, 0.730 with T2WI plus DWI and 0.793 with fusion MRI for T stage ≥2. Fused high b value DWI and T2WI may be a promising non-contrast MRI technique for assessing depth of invasion in bladder cancer. (orig.)

  10. Non-contrast magnetic resonance imaging for bladder cancer: fused high b value diffusion-weighted imaging and T2-weighted imaging helps evaluate depth of invasion

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Minsu; Oh, Young Taik; Jung, Dae Chul; Park, Sung Yoon [Yonsei University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Shin, Su-Jin [Yonsei University College of Medicine, Department of Pathology, Seoul (Korea, Republic of); Hanyang University College of Medicine, Department of Pathology, Seoul (Korea, Republic of); Cho, Nam Hoon [Yonsei University College of Medicine, Department of Pathology, Seoul (Korea, Republic of); Choi, Young Deuk [Yonsei University College of Medicine, Department of Urology, Seoul (Korea, Republic of)

    2017-09-15

    To investigate the utility of fused high b value diffusion-weighted imaging (DWI) and T2-weighted imaging (T2WI) for evaluating depth of invasion in bladder cancer. We included 62 patients with magnetic resonance imaging (MRI) and surgically confirmed urothelial carcinoma in the urinary bladder. An experienced genitourinary radiologist analysed the depth of invasion (T stage <2 or ≥2) using T2WI, DWI, T2WI plus DWI, and fused DWI and T2WI (fusion MRI). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were investigated. Area under the curve (AUC) was analysed to identify T stage ≥2. The rate of patients with surgically confirmed T stage ≥2 was 41.9% (26/62). Sensitivity, specificity, PPV, NPV and accuracy were 50.0%, 55.6%, 44.8%, 60.6% and 53.2%, respectively, with T2WI; 57.7%, 77.8%, 65.2%, 71.8% and 69.4%, respectively, with DWI; 65.4%, 80.6%, 70.8%, 76.3% and 74.2%, respectively, with T2WI plus DWI and 80.8%, 77.8%, 72.4%, 84.9% and 79.0%, respectively, with fusion MRI. AUC was 0.528 with T2WI, 0.677 with DWI, 0.730 with T2WI plus DWI and 0.793 with fusion MRI for T stage ≥2. Fused high b value DWI and T2WI may be a promising non-contrast MRI technique for assessing depth of invasion in bladder cancer. (orig.)

  11. Evaluation with fat-suppression fast spin-echo T2-weighted images for bone and soft tissue disorders

    International Nuclear Information System (INIS)

    Kakitsubata, Yousuke; Watanabe, Katsushi; Kakitsubata, Sachiko; Shimizu, Tokiyoshi.

    1997-01-01

    One hundred and sixty-four magnetic resonance (MR) studies of bone or soft tissue disorders were evaluated with T2-weighted fast spin echo (FSE) imaging and T2-weighted fat-suppressed FSE (FS-FSE) imaging. Fifty-two patients with bone contusion of the knee were also evaluated with conventional T2-weighted SE imaging and T2-weighted FS-FSE imaging. In 50 of 71 patients (70.4%), areas of high signal intensity in bone marrow were more clearly demonstrated on T2-weighted FS-FSE images than on T2-weighted FSE image. Edema or inflammation of soft tissues were also clearly revealed on T2-weighted FS-FSE images. In 27 of 32 patients (84%), bone contusions were more apparently shown on T2-weighted FS-FSE images than on conventional T2-weighted SE image. T2-weighted FS-FSE imaging is a sensitive method of evaluating the long T2 lesions of bone or soft tissue disorders. (author)

  12. T2-weighted imaging of the heart—A pictorial review

    International Nuclear Information System (INIS)

    Mirakhur, Anirudh; Anca, Nicoleta; Mikami, Yoko; Merchant, Naeem

    2013-01-01

    Spin-Echo techniques in cardiovascular magnetic resonance (CMR) have been used for decades, primarily to image cardiac anatomy. More recently, T2-weighted (T2W) imaging has seen an increased role in CMR protocols, especially in tissue characterization in acute myocardial processes. This article will review current methodologies of cardiac T2W acquisition and their limitations, as well as approach to both semi-quantitative and quantitative analyses. The appearance and utility of T2W imaging in a myriad of pathologic myocardial processes such as acute myocardial infarction, acute viral myocarditis, reversible stress-related cardiomyopathy, hypertrophic cardiomyopathy, and cardiac sarcoidosis, will also be discussed

  13. Comparison among T1-weighted magnetic resonance imaging, modified dixon method, and magnetic resonance spectroscopy in measuring bone marrow fat.

    Science.gov (United States)

    Shen, Wei; Gong, Xiuqun; Weiss, Jessica; Jin, Ye

    2013-01-01

    An increasing number of studies are utilizing different magnetic resonance (MR) methods to quantify bone marrow fat due to its potential role in osteoporosis. Our aim is to compare the measurements of bone marrow fat among T1-weighted magnetic resonance imaging (MRI), modified Dixon method (also called fat fraction MRI (FFMRI)), and magnetic resonance spectroscopy (MRS). Contiguous MRI scans were acquired in 27 Caucasian postmenopausal women with a modified Dixon method (i.e., FFMRI). Bone marrow adipose tissue (BMAT) of T1-weighted MRI and bone marrow fat fraction of the L3 vertebra and femoral necks were quantified using SliceOmatic and Matlab. MRS was also acquired at the L3 vertebra. Correlation among the three MR methods measured bone marrow fat fraction and BMAT ranges from 0.78 to 0.88 (P BMAT measured by T1-weighted MRI and bone marrow fat fraction measured by modified FFMRI is 0.86 (P < 0.001) in femoral necks. There are good correlations among T1-weighted MRI, FFMRI, and MRS for bone marrow fat quantification. The inhomogeneous distribution of bone marrow fat, the threshold segmentation of the T1-weighted MRI, and the ambiguity of the FFMRI may partially explain the difference among the three methods.

  14. Postcontrast T1-weighted brain magnetic resonance imaging in pediatric patients: comparison between postcontrast fat-suppression imaging and conventional T1-weighted or magnetization transfer imaging

    International Nuclear Information System (INIS)

    Lee, Choong Wook; Goo, Hyun Woo

    2004-01-01

    We wished to assess the merits and weaknesses of postcontrast fat-suppression (FS) brain MR imaging in children for the evaluation of various enhancing lesions as compared with postcontrast conventional T1-weighted or magnetization transfer (MT) imaging. We reviewed the records of those patients with enhancing lesions on brain MR imaging who had undergone both FS imaging and one of the conventional T1-weighted or MT imaging as a post-contrast T1-weighted brain MR imaging. Thirty-one patients (21 male, 10 female; mean age, 8.7 years) with 38 enhancing lesions (18 intra-axial, 16 extra-axial and 4 orbital locations) were included in this study. There were 27 pairs of FS and conventional imagings, and 13 pairs of FS and MT imagings available for evaluation. Two radiologists visually assessed by consensus the lesions' conspicuity, and they also looked for the presence of flow or susceptibility artifacts in a total of 40 pairs of MR imagings. For 19 measurable lesions (14 pairs of FS and conventional T1-weighted imagings, 5 pairs of FS and MT imagings), the contrast ratios between the lesion and the normal brain ([SIlesion-SIwater]/[SInormal brain-SIwater]) were calculated and compared. Compared with conventional imaging, the lesion conspicuity on FS imaging was better in 10 cases (7 extra-axial lesions, 2 orbital lesions and 1 fat-containing intra-axial lesion), equal in 16 cases, and worse in one case. Compared with MT imaging, the lesion conspicuity on FS imaging was better in 3 cases (2 extra-axial lesions and 1 intra-axial lesion), equal in 8 cases, and worse in 2 cases. Image quality of FS imaging was compromised by flow or susceptibility artifacts for 7 patients. The contrast ratios for FS imaging were not significantly different from those for conventional imaging (2.2±0.7 vs. 2.2±0.6, respectively, p=0.914) and they were significantly lower than those for MT imaging (2.4±0.8 vs. 4.5±1.5, respectively, p=0.018). Postcontrast FS brain MR imaging appears to be

  15. Optimal MR pulse sequences for hepatic hemangiomas : comparison of T2-weighted turbo-spin-echo, T2-weighted breath-hold turbo-spin-echo, and T1-weighted FLASH dynamic imaging

    International Nuclear Information System (INIS)

    Wang, Wen Chao; Choi, Byung Ihn; Han, Joon Koo; Kim, Tae Kyoung; Cho, Soon Gu

    1997-01-01

    To optimize MR imaging pulse sequences in the imaging of hepatic hemangioma and to evaluate on dynamic MR imaging the enhancing characteristics of the lesions. Twenty patients with 35 hemangiomas were studied by using Turbo-spin-echo (TSE) sequence (T2-weighted, T2- and heavily T2-weighted breath-hold) and T1-weighted FLASH imaging acquired before, immediately on, and 1, 3 and 5 minutes after injection of a bolus of Gd-DTPA (0.1mmol/kg). Phased-array multicoil was employed. Images were quantitatively analyzed for lesion-to-liver signal difference to noise ratios (SD/Ns), and lesion-to-liver signal ratios (H/Ls), and qualitatively analyzed for lesion conspicuity. The enhancing characteristics of the hemangiomas were described by measuring the change of signal intensity as a curve in T1-weighted FLASH dynamic imaging. For T2-weighted images, breath-hold T2-weighted TSE had a slightly higher SD/N than other pulse sequences, but there was no statistical difference in three fast pulse sequences (p=0.211). For lesion conspicuity, heavily T2-weighted breath-hold TSE images was superior to T2-weighted breath-hold or non-breath-hold TSE (H/L, 5.75, 3.81, 2.87, respectively, p<0.05). T2-weighted breath-hold TSE imaging was more effective than T2-weighted TSE imaging in removing lesion blurring or lack of sharpness, and there was a 12-fold decrease in acquisition time (20sec versus 245 sec). T1-weighted FLASH dynamic images of normal liver showed peak enhancement at less than 1 minute, and of hemangioma at more than 3 minutes;the degree of enhancement for hemangioma decreased after a 3 minute delay. T2-weighed breath-hold TSE imaging and Gd-DTPA enhanced FLASH dynamic imaging with 5 minutes delay are sufficient for imaging hepatic hemangiomas

  16. T2-weighted four dimensional magnetic resonance imaging with result-driven phase sorting

    International Nuclear Information System (INIS)

    Liu, Yilin; Yin, Fang-Fang; Cai, Jing; Czito, Brian G.; Bashir, Mustafa R.

    2015-01-01

    Purpose: T2-weighted MRI provides excellent tumor-to-tissue contrast for target volume delineation in radiation therapy treatment planning. This study aims at developing a novel T2-weighted retrospective four dimensional magnetic resonance imaging (4D-MRI) phase sorting technique for imaging organ/tumor respiratory motion. Methods: A 2D fast T2-weighted half-Fourier acquisition single-shot turbo spin-echo MR sequence was used for image acquisition of 4D-MRI, with a frame rate of 2–3 frames/s. Respiratory motion was measured using an external breathing monitoring device. A phase sorting method was developed to sort the images by their corresponding respiratory phases. Besides, a result-driven strategy was applied to effectively utilize redundant images in the case when multiple images were allocated to a bin. This strategy, selecting the image with minimal amplitude error, will generate the most representative 4D-MRI. Since we are using a different image acquisition mode for 4D imaging (the sequential image acquisition scheme) with the conventionally used cine or helical image acquisition scheme, the 4D dataset sufficient condition was not obviously and directly predictable. An important challenge of the proposed technique was to determine the number of repeated scans (N_R) required to obtain sufficient phase information at each slice position. To tackle this challenge, the authors first conducted computer simulations using real-time position management respiratory signals of the 29 cancer patients under an IRB-approved retrospective study to derive the relationships between N_R and the following factors: number of slices (N_S), number of 4D-MRI respiratory bins (N_B), and starting phase at image acquisition (P_0). To validate the authors’ technique, 4D-MRI acquisition and reconstruction were simulated on a 4D digital extended cardiac-torso (XCAT) human phantom using simulation derived parameters. Twelve healthy volunteers were involved in an IRB-approved study

  17. Sub-Millimeter T2 Weighted fMRI at 7 T: Comparison of 3D-GRASE and 2D SE-EPI

    Directory of Open Access Journals (Sweden)

    Valentin G. Kemper

    2015-05-01

    Full Text Available Functional magnetic resonance imaging (fMRI allows studying human brain function non-invasively up to the spatial resolution of cortical columns and layers. Most fMRI acquisitions rely on the blood oxygenation level dependent (BOLD contrast employing T2* weighted 2D multi-slice echo-planar imaging (EPI. At ultra-high magnetic field (i.e. 7 T and above, it has been shown experimentally and by simulation, that T2 weighted acquisitions yield a signal that is spatially more specific to the site of neuronal activity at the cost of functional sensitivity. This study compared two T2 weighted imaging sequences, inner-volume 3D Gradient-and-Spin-Echo (3D-GRASE and 2D Spin-Echo EPI (SE-EPI, with evaluation of their imaging point-spread function, functional specificity, and functional sensitivity at sub-millimeter resolution. Simulations and measurements of the imaging point-spread function revealed that the strongest anisotropic blurring in 3D-GRASE (along the second phase-encoding direction was about 60 % higher than the strongest anisotropic blurring in 2D SE-EPI (along the phase-encoding direction In a visual paradigm, the BOLD sensitivity of 3D-GRASE was found to be superior due to its higher temporal signal-to-noise ratio. High resolution cortical depth profiles suggested that the contrast mechanisms are similar between the two sequences, however, 2D SE-EPI had a higher surface bias owing to the higher T2* contribution of the longer in-plane EPI echo-train for full field of view compared to the reduced field of view of zoomed 3D-GRASE.

  18. Comparison among T1-Weighted Magnetic Resonance Imaging, Modified Dixon Method, and Magnetic Resonance Spectroscopy in Measuring Bone Marrow Fat

    Directory of Open Access Journals (Sweden)

    Wei Shen

    2013-01-01

    Full Text Available Introduction. An increasing number of studies are utilizing different magnetic resonance (MR methods to quantify bone marrow fat due to its potential role in osteoporosis. Our aim is to compare the measurements of bone marrow fat among T1-weighted magnetic resonance imaging (MRI, modified Dixon method (also called fat fraction MRI (FFMRI, and magnetic resonance spectroscopy (MRS. Methods. Contiguous MRI scans were acquired in 27 Caucasian postmenopausal women with a modified Dixon method (i.e., FFMRI. Bone marrow adipose tissue (BMAT of T1-weighted MRI and bone marrow fat fraction of the L3 vertebra and femoral necks were quantified using SliceOmatic and Matlab. MRS was also acquired at the L3 vertebra. Results. Correlation among the three MR methods measured bone marrow fat fraction and BMAT ranges from 0.78 to 0.88 in the L3 vertebra. Correlation between BMAT measured by T1-weighted MRI and bone marrow fat fraction measured by modified FFMRI is 0.86 in femoral necks. Conclusion. There are good correlations among T1-weighted MRI, FFMRI, and MRS for bone marrow fat quantification. The inhomogeneous distribution of bone marrow fat, the threshold segmentation of the T1-weighted MRI, and the ambiguity of the FFMRI may partially explain the difference among the three methods.

  19. Role of T2 weighted magnetic resonance image in chronic phase of head injured patients

    International Nuclear Information System (INIS)

    Uzura, Masahiko; Taguchi, Yoshio; Watanabe, Hiroyuki; Chiba, Syunmei; Matsuzawa, Motoshi

    2002-01-01

    In neuroimaging studies of head injury, addition of echo planar imaging (EPI) T2-weighted images (WI) to routine MR images has been useful in demonstrating small hemorrhagic lesions as magnetic susceptibility artifacts (MSAs). MSAs are often found in the acute or subacute phases of head injured patients with diffuse axonal injury. We studied MSAs in follow-up MR images of patients with diffuse brain injury and discuss the role of EPI T2-WI in patients with chronic phase of head injured patients. This series consisted of 20 patients with diffuse brain injury diagnosed clinically. Their head CT findings were classified into Diffuse Injury I or II according to the CT classification of Marshall et al. All patients underwent long-term follow-up MR examinations. MR findings in chronic phase were divided into three categories in terms of MSAs: group A, MSAs remaining even after disappearance of small traumatic lesions in both T2-WI and fluid attenuated inversion recovery (FLAIR) images (11 cases); group B, MSA (s) that disappeared in association with disappearance of small traumatic lesions (4 cases); and group C, MSAs that remained but could not be differentiated from non-traumatic lesions such as hemorrhagic lacunae or cavernoma (5 cases). Adding EPI T2-WI to routine MR images can provide useful information in visualizing old traumatic lesions of the brain in patients with diffuse brain injury even if no neuroimaging studies in acute or subacute phase. (author)

  20. SU-E-J-157: Improving the Quality of T2-Weighted 4D Magnetic Resonance Imaging for Clinical Evaluation

    International Nuclear Information System (INIS)

    Du, D; Mutic, S; Hu, Y; Caruthers, S; Glide-Hurst, C; Low, D

    2014-01-01

    Purpose: To develop an imaging technique that enables us to acquire T2- weighted 4D Magnetic Resonance Imaging (4DMRI) with sufficient spatial coverage, temporal resolution and spatial resolution for clinical evaluation. Methods: T2-weighed 4DMRI images were acquired from a healthy volunteer using a respiratory amplitude triggered T2-weighted Turbo Spin Echo sequence. 10 respiratory states were used to equally sample the respiratory range based on amplitude (0%, 20%i, 40%i, 60%i, 80%i, 100%, 80%e, 60%e, 40%e and 20%e). To avoid frequent scanning halts, a methodology was devised that split 10 respiratory states into two packages in an interleaved manner and packages were acquired separately. Sixty 3mm sagittal slices at 1.5mm in-plane spatial resolution were acquired to offer good spatial coverage and reasonable spatial resolution. The in-plane field of view was 375mm × 260mm with nominal scan time of 3 minutes 42 seconds. Acquired 2D images at the same respiratory state were combined to form the 3D image set corresponding to that respiratory state and reconstructed in the coronal view to evaluate whether all slices were at the same respiratory state. 3D image sets of 10 respiratory states represented a complete 4D MRI image set. Results: T2-weighted 4DMRI image were acquired in 10 minutes which was within clinical acceptable range. Qualitatively, the acquired MRI images had good image quality for delineation purposes. There were no abrupt position changes in reconstructed coronal images which confirmed that all sagittal slices were in the same respiratory state. Conclusion: We demonstrated it was feasible to acquire T2-weighted 4DMRI image set within a practical amount of time (10 minutes) that had good temporal resolution (10 respiratory states), spatial resolution (1.5mm × 1.5mm × 3.0mm) and spatial coverage (60 slices) for future clinical evaluation

  1. Magnetic Resonance Cholangiopancreatography: Image Quality, Ductal Morphology, and Value of Additional T2- and T1-weighted Sequences for the Assessment of Suspected Pancreatic Cancer

    International Nuclear Information System (INIS)

    Lopez Haenninen, E.; Ricke, H.; Amthauer, H.; Roettgen, R.; Boehmig, M.; Langrehr, J.; Pech, M.; Denecke, T.; Rosewicz, S.; Felix, R.

    2005-01-01

    Purpose: To assess image quality and duct morphology on magnetic resonance cholangiopancreatography (MRCP) and also the value of additional T2- and T1-weighted sequences for differentiation of benignity and malignancy in patients with suspected pancreatic tumors. Material and Methods: One-hundred-and-fourteen patients received MRCP and unenhanced and contrast material-enhanced MR imaging. MR results were analyzed independently by two blinded readers, and subsequently correlated with the results from surgery, biopsy, and follow-up. Assessment included the evaluation of image quality, duct visualization and morphology, and the differentiation of pancreatic lesion status (benign versus malignant).Results: Overall, 49 patients had benign final diagnoses, while 65 had a malignant diagnosis. Image quality of single-shot thick-slab MRCP was rated significantly better than the MIP images of multisection MRCP. With MRCP alone, the two readers' accuracy in the assessment of pancreatic lesion status was 72% (95% CI, 64% to 83%) and 69% (95% CI, 56% to 77%), respectively; with the addition of T2- and T1-weighted images the accuracy significantly improved to 89% (95% CI, 82% to 95%) and 84% (95% CI, 77% to 92%) for readers 1 and 2, respectively. Conclusion: Single-shot thick-slab MRCP and multisection MRCP provide complementary results; however, single-shot MRCP had superior image quality. Moreover, assessment of ductal morphology with MRCP alone facilitated the diagnosis of different pathologic conditions of the pancreatobiliary system in the majority of patients. However, with the addition of T2- and T1-weighted sequences the overall diagnostic accuracy was significantly improved and thus we consider that a comprehensive MR approach should comprise both MRCP techniques and parenchymal sequences

  2. Bilateral Pulvinar Signal Intensity Decrease on T2-Weighted Images in Patients with Aspartylglucosaminuria

    International Nuclear Information System (INIS)

    Autti, T.; Loennqvist, T.; Joensuu, R.

    2008-01-01

    Background: Aspartylglucosaminuria (AGU) is an autosomal recessive lysosomal disease caused by deficiency of aspartylglucosaminidase. A thalamic T2 signal intensity decrease is associated with lysosomal diseases. Purpose: To investigate thalamic signal intensity in AGU by performing a retrospective review of brain magnetic resonance (MR) imaging studies of AGU patients. Material and Methods: A total of 25 MR examinations were available for 11 patients aged between 3 and 32 years (four patients underwent bone marrow transplantation). Of these, 13 examinations were performed after bone marrow transplantation. Five patients had from two to six examinations, and six patients had one examination each. In every patient, the diagnosis of AGU was confirmed by blood and urine tests. Eighteen examinations were performed with a 1.0T imager including dual spin-echo T2 and proton density (PD) axial and coronal images, and 10 examinations also included T1-weighted images. Seven examinations were performed with a 1.5T imager including turbo spin-echo axial and coronal T2-weighted images and axial fluid-attenuated inversion recovery (FLAIR) images; three examinations included T1-weighted three-dimensional magnetization-prepared rapid acquisition gradient-echo (3D MPRAGE) images. The signal intensity of the thalamus and pulvinar in every sequence was compared to that of the putamina. Results: In AGU, thalamic alterations were first detectable on T2-weighted images (25 examinations in 11 patients) from the age of 3 years 6 months, showing decreased signal intensity in 21 of 24 examinations. T1-weighted images (13 examinations) showed slightly increased thalamic signal intensity in five out of seven examinations from the age of 7 years, and PD images (19 examinations) showed decreased signal intensity from the age of 16 years (three examinations). The pulvinar showed decreased signal intensity on spin-echo T2-weighted images for 14 of 18 examinations or on FLAIR sequences for seven

  3. Myocardial area at risk after ST-elevation myocardial infarction measured with the late gadolinium enhancement after scar remodeling and T2-weighted cardiac magnetic resonance imaging

    DEFF Research Database (Denmark)

    Lønborg, Jacob; Engstrøm, Thomas; Mathiasen, Anders B

    2011-01-01

    To evaluate the myocardial area at risk (AAR) measured by the endocardial surface area (ESA) method on late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) when applied after scar remodeling (3 months after index infarction) compared to T2-weighted CMR imaging. One hundred...... and sixty nine patients with ST-elevation myocardial infarction, treated with primary percutaneous coronary intervention, underwent one CMR within 1 week after index treatment to determine the AAR with T2-weighted imaging and a second scan 3 months after to measure AAR with the ESA method...

  4. Myocardial area at risk after ST-elevation myocardial infarction measured with the late gadolinium enhancement after scar remodeling and T2-weighted cardiac magnetic resonance imaging

    DEFF Research Database (Denmark)

    Lønborg, Jacob; Engstrøm, Thomas; Mathiasen, Anders B

    2012-01-01

    To evaluate the myocardial area at risk (AAR) measured by the endocardial surface area (ESA) method on late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) when applied after scar remodeling (3 months after index infarction) compared to T2-weighted CMR imaging. One hundred...... and sixty nine patients with ST-elevation myocardial infarction, treated with primary percutaneous coronary intervention, underwent one CMR within 1 week after index treatment to determine the AAR with T2-weighted imaging and a second scan 3 months after to measure AAR with the ESA method...

  5. Magnetic properties of Np2T2Sn compounds

    International Nuclear Information System (INIS)

    Sanchez, J.P.; Colineau, E.; Jeandey, C.; Oddou, J.L.; Rebizant, J.; Seret, A.; Spirlet, J.C.

    1994-01-01

    The magnetic properties of the Np 2 T 2 Sn series investigated by 237 Np Moessbauer spectroscopy are reported. Magnetic ordering is shown to occur for T = Ni, Pd, Pt, whereas the Np ions do not carry a local moment when T = Co, Ru, Rh. Comparison is made with the corresponding Np 2 T 2 In and U 2 T 2 Sn compounds. (authors). 5 refs., 3 figs

  6. Fat-suppressed MRI of musculoskeletal infection: fast T2-weighted techniques versus gadolinium-enhanced T1-weighted images

    International Nuclear Information System (INIS)

    Miller, T.T.; Randolph, D.A. Jr.; Staron, R.B.; Feldman, F.; Cushin, S.

    1997-01-01

    Purpose. To investigate gadolinium's role in imaging musculoskeletal infection by comparing the conspicuity and extent of inflammatory changes demonstrated on gadolinium-enhanced fat-suppressed T1-weighted images versus fat-suppressed fast T2-weighted sequences. Design. Eighteen patients with infection were imaged in a 1.5-T unit, using frequency-selective and/or inversion recovery fat-suppressed fast T2-weighted images (T2WI) and gadolinium-enhanced frequency-selective fat-suppressed T1-weighted images (T1WI). Thirty-four imaging planes with both a fat-suppressed gadolinium-enhanced T1-weighted sequence and a fat-suppressed T2-weighted sequence were obtained. Comparison of the extent and conspicuity of signal intensity changes was made for both bone and soft tissue in each plane. Results. In bone, inflammatory change was equal in extent and conspicuity on fat-suppressed T2WI and fat-suppressed T1WI with gadolinium in 19 planes, more extensive or conspicuous on T2WI in three planes, and less so on T2WI in two planes. Marrow was normal on all three sequences in 10 cases. In soft tissue, inflammatory change was seen equally well in 20 instances, more extensively or conspicuously on the T2WI in 11 instances, and less so on T2WI in 2 instances. One case had no soft tissue involvement on any of the sequences. Five abscesses and three joint effusions were present, all more conspicuously delineated from surrounding inflammatory change on the fat-saturated T1WI with gadolinium. The average imaging time for the fat-saturated T1WI with gadolinium was 6.75 min, while that of the T2-weighted sequences was 5.75 min. Conclusion. Routine use of gadolinium is not warranted. Instead, gadolinium should be reserved for clinically suspected infection in or around a joint, and in cases refractory to medical or surgical treatment due to possible abscess formation. (orig.)

  7. A new look at the fetus: Thick-slab T2-weighted sequences in fetal MRI

    International Nuclear Information System (INIS)

    Brugger, Peter C.; Mittermayer, Christoph; Prayer, Daniela

    2006-01-01

    Although magnetic resonance imaging (MRI) of the fetus is considered an established adjunct to fetal ultrasound, stacks of images alone cannot provide an overall impression of the fetus. The present study evaluates the use of thick-slab T2-weighted MR images to obtain a three-dimensional impression of the fetus using MRI. A thick-slab T2-weighted sequence was added to the routine protocol in 100 fetal MRIs obtained for various indications (19th to 37th gestational weeks) on a 1.5 T magnet using a five-element phased-array surface coil. Slice thickness adapted to fetal size and uterine geometry varied between 25 and 50 mm, as did the field of view (250-350 mm). Acquisition of one image took less than 1 s. The pictorial essay shows that these images visualize fetal anatomy in a more comprehensive way than is possible with a series of 3-4 mm thick slices. These thick-slab images facilitate the assessment of the whole fetus, fetal proportions, surface structures, and extremities. Fetal pathology may be captured in one image. Thick-slab T2-weighted images provide additional information that cannot be gathered from a series of images and are considered a valuable adjunct to conventional 2D MR images

  8. A new look at the fetus: Thick-slab T2-weighted sequences in fetal MRI

    Energy Technology Data Exchange (ETDEWEB)

    Brugger, Peter C. [Center of Anatomy and Cell Biology, Integrative Morphology Group, Medical University of Vienna, Vienna (Austria)]. E-mail: peter.brugger@meduniwien.ac.at; Mittermayer, Christoph [Department of Neonatology and Intensive Care, University Hospital of Vienna (Austria); Prayer, Daniela [Department of Neuroradiology, University Clinics of Radiodiagnostics, Medical University of Vienna, Vienna (Austria)

    2006-02-15

    Although magnetic resonance imaging (MRI) of the fetus is considered an established adjunct to fetal ultrasound, stacks of images alone cannot provide an overall impression of the fetus. The present study evaluates the use of thick-slab T2-weighted MR images to obtain a three-dimensional impression of the fetus using MRI. A thick-slab T2-weighted sequence was added to the routine protocol in 100 fetal MRIs obtained for various indications (19th to 37th gestational weeks) on a 1.5 T magnet using a five-element phased-array surface coil. Slice thickness adapted to fetal size and uterine geometry varied between 25 and 50 mm, as did the field of view (250-350 mm). Acquisition of one image took less than 1 s. The pictorial essay shows that these images visualize fetal anatomy in a more comprehensive way than is possible with a series of 3-4 mm thick slices. These thick-slab images facilitate the assessment of the whole fetus, fetal proportions, surface structures, and extremities. Fetal pathology may be captured in one image. Thick-slab T2-weighted images provide additional information that cannot be gathered from a series of images and are considered a valuable adjunct to conventional 2D MR images.

  9. Diagnostic performance of dark-blood T2-weighted CMR for evaluation of acute myocardial injury.

    Science.gov (United States)

    Srichai, Monvadi B; Lim, Ruth P; Lath, Narayan; Babb, James; Axel, Leon; Kim, Daniel

    2013-01-01

    We compared the image quality and diagnostic performance of 2 fat-suppression methods for black-blood T2-weighted fast spin-echo (FSE), which are as follows: (a) short T1 inversion recovery (STIR; FSE-STIR) and (b) spectral adiabatic inversion recovery (SPAIR; FSE-SPAIR), for detection of acute myocardial injury. Edema-sensitive T2-weighted FSE cardiac magnetic resonance (CMR) imaging is useful in detecting acute myocardial injury but may experience reduced myocardial signal and signal dropout. The SPAIR pulse aims to eliminate artifacts associated with the STIR pulse. A total of 65 consecutive patients referred for CMR evaluation of myocardial structure and function underwent FSE-STIR and FSE-SPAIR, in addition to cine and late gadolinium enhancement (LGE) CMR. T2-weighted FSE images were independently evaluated by 2 readers for image quality and artifacts (Likert scale of 1-5; best-worst) and presence of increased myocardial signal suggestive of edema. In addition, clinical CMR interpretation, incorporating all CMR sequences available, was recorded for comparison. Diagnostic performance of each T2-weighted sequence was measured using recent (T2, and wall motion. There was a statistically significant difference in sensitivity between the clinical interpretation and each of the T2-weighted sequences but not between each T2-weighted sequence. Although FSE-SPAIR demonstrated significantly improved image quality and decreased artifacts, isolated interpretations of each T2-weighted technique demonstrated high specificity but overall low sensitivity for the detection of myocardial injury, with no difference in accuracy between the techniques. However, real-world interpretation in combination with cine and LGE CMR methods significantly improves the overall sensitivity and diagnostic performance.

  10. T2-weighted endorectal magnetic resonance imaging of prostate cancer after external beam radiation therapy

    International Nuclear Information System (INIS)

    Westphalen, Antonio C.; Kurhanewicz, John; Cunha, Rui M.G.; Hsu, I-Chow; Kornak, John; Zhao, Shoujun; Coakley, Fergus V.

    2009-01-01

    Purpose: To retrospectively determine the accuracy of T2-weighted endorectal MR imaging in the detection of prostate cancer after external beam radiation therapy and to investigate the relationship between imaging accuracy and time since therapy. Materials and Methods: Institutional review board approval was obtained and the study was HIPPA compliant. We identified 59 patients who underwent 1.5 Tesla endorectal MR imaging of the prostate between 1999 and 2006 after definitive external beam radiation therapy for biopsy-proven prostate cancer. Two readers recorded the presence or absence of tumor on T2-weighted images. Logistic regression and Fisher's exact tests for 2x2 tables were used to determine the accuracy of imaging and investigate if accuracy differed between those imaged within 3 years of therapy (n = 25) and those imaged more than 3 years after therapy (n = 34). Transrectal biopsy was used as the standard of reference for the presence or absence of recurrent cancer. Results: Thirty-four of 59 patients (58%) had recurrent prostate cancer detected on biopsy. The overall accuracy of T2-weighted MR imaging in the detection cancer after external beam radiation therapy was 63% (37/59) for reader 1 and 71% for reader 2 (42/59). For both readers, logistic regression showed no difference in accuracy between those imaged within 3 years of therapy and those imaged more than 3 years after therapy (p = 0.86 for reader 1 and 0.44 for reader 2). Conclusion: T2-weighted endorectal MR imaging has low accuracy in the detection of prostate cancer after external beam radiation therapy, irrespective of the time since therapy. (author)

  11. MR imaging pulse sequence rationale: SD-, T1-, and T2-weighted images

    International Nuclear Information System (INIS)

    Sax, S.; Weathers, S.W.; Schneiders, N.J.; Horowitz, B.L.; Mawad, M.E.; Sandlin, M.E.; Blackwell, R.; Bryan, R.N.

    1986-01-01

    Over 500 patients have been examined with a pulse sequence designed to provide spin-density (SD)-weighted images (TR=3 sec, TE=35 msec), T1-weighted images (TR=0.3 sec, TE=35msec), and T2-weighted images (TR=3 sec, TE=105 msec) from which calculated ''synthesized'' images and SD, T1, and T2 calculated images could be obtained. Each image contributes unique information. SD-weighted images optimally display anatomy and often best highlight pathology. T1-weighted images are critical in assessing cerebral hemorrhages. T2-weighted images best display most lesions, but yield incomplete information in 35% of cases. All three types of ''weighted'' images are necessary to optimally display anatomy and fully characterize a lesion. Computerized calculations and simulations suggest that no other combination of pulse sequences yields equal information for a given examination time

  12. Significance of T2 weighted image on magnetic resonance. Imaging in diagnosis of acute cervical cord injury

    International Nuclear Information System (INIS)

    Takahashi, Isao; Kitahara, Takao; Endo, Masataka; Ohwada, Takashi

    1999-01-01

    Thirty-eight patients with acute cervical cord injury with neurological deficit were examined within 72 hours of injury by magnetic resonance imaging (MRI). This study evaluated early MRI as a neurological status and prognostic indicator of the eventual neurological outcome. The neurological status was determined using Frankel classification at admission and follow-up examination. Three different patterns of T2 weighted image (T2WI) on MRI were observed in these patients: 7 patients (Frankel A in all) had coexistence of low and high signal (mixed type); 9 (A in 3, B in 5, C in one) had high signal over more than one spinal segment (diffuse high type); 14 (A in 5, B in 3, C in 6) had high signal within one spinal segment (local high type); 8 (C in 6, D in 2) had no abnormality (normal type). At follow-up examination, the improvement rate was 14.3% for mixed type, 33.3% for diffuse high type, 78.6% for local high type and 100% for normal type. These studies suggest that the early MRI is very useful in the diagnosis of acute cervical cord injury and in predicting neurological recovery. (author)

  13. Are T2-weighted images necessary in renal mass characterization?

    International Nuclear Information System (INIS)

    Dann, Phoebe; Thakur, Ravi; Chin, Deanne; Krinsky, Glenn; Israel, Gary M.

    2006-01-01

    Objective: To determine what role T2-weighted images play in characterizing renal masses. Methods: Forty-four pathologically proven renal masses (34 renal cell carcinomas, 8 oncocytomas, 1 metanephric adenoma, 1 angiomyolipoma without macroscopic fat) and 38 simple renal cysts were evaluated with T1- and T2-weighted images at 1.5 T. Two independent and blinded readers initially characterized all masses using only the T1-weighed images (in- and opposed-phase chemical shift, unenhanced frequency-selective fat-suppressed, gadolinium-enhanced frequency-selective fat-suppressed and subtraction images) and placed each mass into one of three categories: nonsurgical, in need of follow-up, or surgical. The masses were then re-evaluated with the addition of the T2-weighted images. It was determined if the T2-weighted images changed the initial classification. Results: Forty-three of the 44 (98%) pathologically proven renal masses were characterized as a surgical mass using only the T1-weighted images. The remaining renal mass (a renal cell carcinoma) was characterized as a mass in which follow-up exams would be suggested. Thirty-eight of 38 (100%) simple renal cysts were correctly characterized using only the T1-weighted images. The T2-weighted images did not change the initial interpretation of the T1-weighted images in any of the cases. Conclusion: The results of this study suggest that T2-weighted images are not necessary in the evaluation of all renal masses and are specifically not necessary in the differentiation of solid and cystic renal neoplasms from simple renal cysts

  14. Application of fast spin-echo T2-weighted imaging for examination of the neurocranium. Comparison with the conventional T2-weighted spin-echo sequence

    International Nuclear Information System (INIS)

    Siewert, C.; Hosten, N.; Felix, R.

    1994-01-01

    T 2 -weighted spin-echo imaging is the standard screening procedure in MR imaging of the neutrocranium. We evaluated fast spin-echo T 2 -weighted imaging (TT 2 ) of the neurocranium in comparison to conventional spin-echo T 2 -weighted imaging (T 2 ). Signal-to-noise and contrast-to-noise ratio of normal brain tissues (basal ganglia, grey and white matter, CSF fluid) and different pathologies were calculated. Signal-to-noise ratio and contrast-to-noise ratio were significantly higher than TT 2 than in T 2 (with the exception of grey-to-white matter contrast). Tissues with increased content of water protons (mobile protons) showed the highest contrast to surrounding tissues. The increased signal intensity of fat must be given due attention in fatty lesions. Because the contrast-to-noise ratio between white matter and basal ganglia is less in TT 2 , Parkinson patients have to be examined by conventional T 2 . If these limitations are taken into account, fast spin-echo T 2 -weighted imaging is well appropriate for MR imaging of the neurocranium, resulting in heavy T 2 -weighting achieved in a short acquisition time. (orig.) [de

  15. Cardiovascular Magnetic Resonance T2-STIR Imaging is Unable to Discriminate Between Intramyocardial Haemorrhage and Microvascular Obstruction

    DEFF Research Database (Denmark)

    Søvsø Szocska Hansen, Esben; Pedersen, Steen Fjord; Pedersen, Steen Bønløkke

    2015-01-01

    Recent studies have used cardiovascular magnetic resonance (CMR) and T2-weighted short tau inversion recovery (T2-STIR) imaging to detect intramyocardial haemorrhage (IMH) as a measure of ischemic/reperfusion injury. We investigated the ability of T2-STIR to differentiate between microvascular...

  16. Optimisation of T2*-weighted MRI for the detection of small veins in multiple sclerosis at 3 T and 7 T

    International Nuclear Information System (INIS)

    Dixon, Jennifer Elizabeth; Simpson, Ashley; Mistry, Niraj; Evangelou, Nikos; Morris, Peter Gordon

    2013-01-01

    T 2 * -weighted magnetic resonance imaging at 7 T has recently been shown to allow differentiation between white-matter multiple sclerosis lesions and asymptomatic white-matter lesions, by the presence or absence of a detectable central blood vessel. The aim of the present work is to improve the technique by increasing the sensitivity to veins at both 3 T and 7 T, and to assess the benefit of ultra-high-field imaging. Signal-to-noise ratio (SNR) measurements and simulations are used to compare the sensitivity of magnitude T 2 * -weighted and susceptibility-weighted images for the detection of small veins (<1 pixel in diameter), both with and without the use of gadolinium. The simulations are used to predict the optimal scanning parameters in order to increase the sensitivity to these veins at both field strengths, and to reduce the inherent dependence on vessel orientation. The sensitivities of the sequences at both field strengths are compared, theoretically and experimentally, in order to quantify the benefit of imaging at ultra-high-field. Subjects with multiple sclerosis (MS) are scanned at both field strengths, using the optimised sequence parameters, as well as those used in previously published work, and the optimisation is shown to improve the detection of veins within lesions

  17. High-resolution heavily T2-weighted magnetic resonance imaging for evaluation of the pituitary stalk in children with ectopic neurohypophysis

    Energy Technology Data Exchange (ETDEWEB)

    Sanharawi, Imane El; Tzarouchi, Loukia [Hopital Robert Debre, APHP, Service de Radiologie Pediatrique, Paris (France); Cardoen, Liesbeth [Hopital Robert Debre, APHP, Service de Radiologie Pediatrique, Paris (France); Universite Paris Diderot, Paris (France); Martinerie, Laetitia; Leger, Juliane; Carel, Jean-Claude [Universite Paris Diderot, Paris (France); Inserm U1141, DHU PROTECT, Paris (France); Hopital Robert Debre, APHP, Service d' Endocrinologie Pediatrique, Paris (France); Elmaleh-Berges, Monique [Hopital Robert Debre, APHP, Service de Radiologie Pediatrique, Paris (France); Inserm U1141, DHU PROTECT, Paris (France); Alison, Marianne [Hopital Robert Debre, APHP, Service de Radiologie Pediatrique, Paris (France); Universite Paris Diderot, Paris (France); Inserm U1141, DHU PROTECT, Paris (France)

    2017-05-15

    In anterior pituitary deficiency, patients with non visible pituitary stalk have more often multiple deficiencies and persistent deficiency than patients with visible pituitary stalk. To compare the diagnostic value of a high-resolution heavily T2-weighted sequence to 1.5-mm-thick unenhanced and contrast-enhanced sagittal T1-weighted sequences to assess the presence of the pituitary stalk in children with ectopic posterior pituitary gland. We retrospectively evaluated the MRI data of 14 children diagnosed with ectopic posterior pituitary gland between 2010 and 2014. We evaluated the presence of a pituitary stalk using a sagittal high-resolution heavily T2-weighted sequence and a 1.5-mm sagittal T1-weighted turbo spin-echo sequence before and after contrast medium administration. A pituitary stalk was present on at least one of the sequences in 10 of the 14 children (71%). T2-weighted sequence depicted the pituitary stalk in all 10 children, whereas the 1.5-mm-thick T1-weighted sequence depicted 2/10 (20%) before contrast injection and 8/10 (80%) after contrast injection (P=0.007). Compared with 1.5-mm-thick contrast-enhanced T1-weighted sequences, high-resolution heavily T2-weighted sequence demonstrates better sensitivity in detecting the pituitary stalk in children with ectopic posterior pituitary gland, suggesting that contrast injection is unnecessary to assess the presence of a pituitary stalk in this setting. (orig.)

  18. High-resolution heavily T2-weighted magnetic resonance imaging for evaluation of the pituitary stalk in children with ectopic neurohypophysis.

    Science.gov (United States)

    El Sanharawi, Imane; Tzarouchi, Loukia; Cardoen, Liesbeth; Martinerie, Laetitia; Leger, Juliane; Carel, Jean-Claude; Elmaleh-Berges, Monique; Alison, Marianne

    2017-05-01

    In anterior pituitary deficiency, patients with non visible pituitary stalk have more often multiple deficiencies and persistent deficiency than patients with visible pituitary stalk. To compare the diagnostic value of a high-resolution heavily T2-weighted sequence to 1.5-mm-thick unenhanced and contrast-enhanced sagittal T1-weighted sequences to assess the presence of the pituitary stalk in children with ectopic posterior pituitary gland. We retrospectively evaluated the MRI data of 14 children diagnosed with ectopic posterior pituitary gland between 2010 and 2014. We evaluated the presence of a pituitary stalk using a sagittal high-resolution heavily T2-weighted sequence and a 1.5-mm sagittal T1-weighted turbo spin-echo sequence before and after contrast medium administration. A pituitary stalk was present on at least one of the sequences in 10 of the 14 children (71%). T2-weighted sequence depicted the pituitary stalk in all 10 children, whereas the 1.5-mm-thick T1-weighted sequence depicted 2/10 (20%) before contrast injection and 8/10 (80%) after contrast injection (P=0.007). Compared with 1.5-mm-thick contrast-enhanced T1-weighted sequences, high-resolution heavily T2-weighted sequence demonstrates better sensitivity in detecting the pituitary stalk in children with ectopic posterior pituitary gland, suggesting that contrast injection is unnecessary to assess the presence of a pituitary stalk in this setting.

  19. Utility decay rates of T1-weighted magnetic resonance imaging contrast based on redox-sensitive paramagnetic nitroxyl contrast agents

    International Nuclear Information System (INIS)

    Matsumoto, Ken-ichiro

    2009-01-01

    The availability and applicability of the combination of paramagnetic nitroxyl contrast agent and T 1 -weighted gradient echo (GE)-based dynamic magnetic resonance imaging (MRI) measurement for redox imaging are described. The time courses of T 1 -weighted GE MRI signal intensities according to first-order paramagnetic loss of a nitroxyl contrast agent were simulated for several experimental conditions. The apparent decay rate calculated based on decreasing T 1 -weighted MRI contrast (k MRI ) can show an approximate value of the original decay rate (k true ) discretionarily given for simulation with suitable experimental parameters. The difference between k MRI and k true can be sufficiently small under T 1 -weighted spoiled gradient echo (SPGR) scan conditions (repetition time=75 ms, echo time=3 ms, and flip angle=45deg), with a conventional redox-sensitive nitroxyl contrast agent, such as 4-hydroxy-2,2,6,6,-tetramethylpiperidine-N-oxyl (TEMPOL) and/or 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl (carbamoyl-PROXYL), and with intravenous (i.v.) doses of below 1.5 γmol/g body weight (b.w.) for mice. The results of this simulation suggest that the k MRI of nitroxyl contrast agents can be the primary index of redox status under biological conditions. (author)

  20. Assessment of Myocardial Fibrosis in Mice Using a T2*-Weighted 3D Radial Magnetic Resonance Imaging Sequence.

    Directory of Open Access Journals (Sweden)

    Bastiaan J van Nierop

    Full Text Available Myocardial fibrosis is a common hallmark of many diseases of the heart. Late gadolinium enhanced MRI is a powerful tool to image replacement fibrosis after myocardial infarction (MI. Interstitial fibrosis can be assessed indirectly from an extracellular volume fraction measurement using contrast-enhanced T1 mapping. Detection of short T2* species resulting from fibrotic tissue may provide an attractive non-contrast-enhanced alternative to directly visualize the presence of both replacement and interstitial fibrosis.To goal of this paper was to explore the use of a T2*-weighted radial sequence for the visualization of fibrosis in mouse heart.C57BL/6 mice were studied with MI (n = 20, replacement fibrosis, transverse aortic constriction (TAC (n = 18, diffuse fibrosis, and as control (n = 10. 3D center-out radial T2*-weighted images with varying TE were acquired in vivo and ex vivo (TE = 21 μs-4 ms. Ex vivo T2*-weighted signal decay with TE was analyzed using a 3-component model. Subtraction of short- and long-TE images was used to highlight fibrotic tissue with short T2*. The presence of fibrosis was validated using histology and correlated to MRI findings.Detailed ex vivo T2*-weighted signal analysis revealed a fast (T2*fast, slow (T2*slow and lipid (T2*lipid pool. T2*fast remained essentially constant. Infarct T2*slow decreased significantly, while a moderate decrease was observed in remote tissue in post-MI hearts and in TAC hearts. T2*slow correlated with the presence of diffuse fibrosis in TAC hearts (r = 0.82, P = 0.01. Ex vivo and in vivo subtraction images depicted a positive contrast in the infarct co-localizing with the scar. Infarct volumes from histology and subtraction images linearly correlated (r = 0.94, P<0.001. Region-of-interest analysis in the in vivo post-MI and TAC hearts revealed significant T2* shortening due to fibrosis, in agreement with the ex vivo results. However, in vivo contrast on subtraction images was rather poor

  1. Computer-assisted analysis of peripheral zone prostate lesions using T2-weighted and dynamic contrast enhanced T1-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Vos, Pieter C; Hambrock, Thomas; Barenstz, Jelle O; Huisman, Henkjan J [Department of Radiology, Radboud University Medical Centre, Nijmegen, 6525GA (Netherlands)], E-mail: p.vos@rad.umcn.nl

    2010-03-21

    In this study, computer-assisted analysis of prostate lesions was researched by combining information from two different magnetic resonance (MR) modalities: T2-weighted (T2-w) and dynamic contrast-enhanced (DCE) T1-w images. Two issues arise when incorporating T2-w images in a computer-aided diagnosis (CADx) system: T2-w values are position as well as sequence dependent and images can be misaligned due to patient movement during the acquisition. A method was developed that computes T2 estimates from a T2-w and proton density value and a known sequence model. A mutual information registration strategy was implemented to correct for patient movement. Global motion is modelled by an affine transformation, while local motion is described by a volume preserving non-rigid deformation based on B-splines. The additional value to the discriminating performance of a DCE T1-w-based CADx system was evaluated using bootstrapped ROC analysis. T2 estimates were successfully computed in 29 patients. T2 values were extracted and added to the CADx system from 39 malignant, 19 benign and 29 normal annotated regions. T2 values alone achieved a diagnostic accuracy of 0.85 (0.77-0.92) and showed a significantly improved discriminating performance of 0.89 (0.81-0.95), when combined with DCE T1-w features. In conclusion, the study demonstrated a simple T2 estimation method that has a diagnostic performance such that it complements a DCE T1-w-based CADx system in discriminating malignant lesions from normal and benign regions. Additionally, the T2 estimate is beneficial to visual inspection due to the removed coil profile and fixed window and level settings.

  2. Evaluation of the SLAP lesion using a low-field (0.2T) magnetic resonance system

    International Nuclear Information System (INIS)

    Cho, Yong Soo; Back, Chang Hee; Lee, Kyung Rae; Shin, Yun Hack

    2007-01-01

    To evaluate the diagnostic capabilities of the low-field (0.2T) magnetic resonance (MR) system in the detection of the superior labrum anterior to posterior (SLAP) lesion. One hundred fifty patients underwent magnetic resonance imaging of the shoulder over a 7-month period. Forty-six patients underwent arthroscopic surgery, and the surgical results were correlated with the findings of the MR imaging. Arthroscopic procedures were performed within a mean of 8 days after MR imaging. MR imaging of the shoulder was conducted as follows: shoulder coil; T1-weighted spin echo, coronal-oblique images; T2-weighted gradient echo, coronal-oblique and axial images; and T2-weighted spin echo, coronal oblique and sagittal-oblique images. Prospectively, one radiologist interpreted the MR images. The results of surgery were as follow: SLAP II in 26 shoulders, SLAP III in 1 shoulder, SLAP IV in 1 shoulder, normal labrum in 6 shoulder. For SLAP lesions with a higher grade than type 2, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the low-field MRI were 85.7%, 55.5%. 75%, 71%, and 74%, respectively. There was relatively good agreement for the comparison of the MR results obtained using a low-field MR system with the surgical findings for identifying SLAP lesions

  3. Assessment of diagnosing metastatic bone tumor on T2*-weighted images. Comparison between turbo spin echo (TSE) method and gradient echo (GE) method

    International Nuclear Information System (INIS)

    Hayashi, Takahiko; Sugiyama, Akira; Katayama, Motoyuki

    1996-01-01

    We examined the usefulness of T2 * weighted gradient field echo images for diagnosis for metastatic bone tumors in comparison with T2 weighted turbo spin echo (fast spin echo) images. In T2 * weighted gradient field echo sequence to obtain maximum contrast-to-noise ratio (CNR), we experimentally manipulated flip angle (FA) (5deg-90deg), repetition time (TR) (400, 700 msec), and echo time (TE) (10-50 msec). The best CNR was 16.4 in fast low angle shot (FLASH) (TE: 24 msec, TR: 700 msec, FA: 40deg). Magnetic resonance imaging was carried out in 28 patients with metastatic bone tumors. In addition to conventional T1 weighted spin echo images, T2 weighted turbo spin echo (fast spin echo images) and T2 * weighted gradient field echo images were obtained. T2 * weighted gradient field echo images were superior to T2 weighted turbo spin echo (fast spin echo) images in delineating the tumors, adjacent fat tissues, and bone marrow. (author)

  4. A comparison of lesion detection and conspicuity on T2-weighted images (T2 FFE), FLAIR and diffusion-weighted images in patients with traumatic brain injury

    International Nuclear Information System (INIS)

    Kwon, Eun Yong; Lee, Myeong sub; Kim, Myung Soon; Hong, In Soo; Kim, Young Ju; Whang, Gum

    2001-01-01

    To compare the lesion detectability and conspicuity in traumatic brain injury on T-2 FFE, FLAIR and diffusion weighted imaging (DWI) sequences. Thirty-three patients who underwent MR brain imaging after traumatic brain injury were reviewed. T-2 FFE, FLAIR and diffusion-weighted MR sequences were obtained and were compared in terms of the detectability and conspicuity of intra- and extra-axial lesions which showed abnormal signal intensities. Among 33 patients, a total of 108 lesions were found, T-2 FFE sequences detected 88(81%) of these, FLAIR sequences 91%(84%), and diffusion-weighted sequences 57(52%). In the case of petechial hemorrhagic lesions, 16 were detected by T-2 FFE imaging but only one by FLAIR and one by DWI. Sixteen extra-axial lesions (73%) were detected by T-2 FFE, 21 (95%) by FLAIR, and 11(50%) by DWI. Lesion conspicuity on FLAIR images was judged superior to that on T-2 FFE and diffusion-weighted images in 42 lesions (75%). Eleven extra-axial Lesions (92%) were more conspicuous on FLAIR than on T-2 FFE and DWI. For detecting traumatic brain lesions and determining their conspicuity, FLAIR imaging was more useful than T-2 FFE and diffusion weighting , while T-2 FFE imaging was more sensitive for the detecion of petechial hemorrhage. Although diffusion-weighted imaging was generally inferior to both FLAIR and T-2 FFE in terms of lesion detection and conspicuity, for some lesions it was superior. The results suggest that images obtained at each pulse sequence can be used as complementary imaging sequences, and that in traumatic brain injury, the acquisition of FLAIR, T-2 FFE and diffusion-weighted images is useful

  5. [The use of the T2-weighted turbo-spin-echo sequence in studying the neurocranium. A comparison with the conventional T2-weighted spin-echo sequence].

    Science.gov (United States)

    Siewert, C; Hosten, N; Felix, R

    1994-07-01

    T2-weighted spin-echo imaging is the standard screening procedure in MR imaging of the neurocranium. We evaluated fast spin-echo T2-weighted imaging (TT2) of the neurocranium in comparison to conventional spin-echo T2-weighted imaging (T2). Signal-to-noise and contrast-to-noise ratio of normal brain tissues (basal ganglia, grey and white matter, CSF fluid) and different pathologies were calculated. Signal-to-noise ratio and contrast-to-noise ratio were significantly higher in TT2 than in T2 (with the exception of gray-to-white matter contrast). Tissues with increased content of water protons (mobile protons) showed the highest contrast to surrounding tissues. The increased signal intensity of fat must be given due attention in fatty lesions. Because the contrast-to-noise ratio between white matter and basal ganglia is less in TT2, Parkinson patients have to be examined by conventional T2. If these limitations are taken into account, fast spin-echo T2-weighted imaging is well appropriate for MR imaging of the neurocranium, resulting in heavy T2-weighting achieved in a short acquisition time.

  6. Difference between T1 and T2 weighted MR images in avascular necrosis of the femoral head

    International Nuclear Information System (INIS)

    Kokubo, Takashi; Yoshikawa, Koki; Itai, Yuzo; Iio, Masahiro; Takatori, Yoshio; Kamogawa, Morihide; Ninomiya, Setsuo

    1990-01-01

    T 1 and T 2 weighted MR images were compared in 32 hips with avascular necrosis, and the difference between them was discussed. In 27 of 32 hips, abnormal low intensity area in the affected femoral head is smaller in T 2 weighted images than in T 1 weighted images. The area of low intensity on T 1 weighted image and high on T 2 weighted image might be granuloma in reactive tissue and surrounding hyperemia. The difference between T 1 and T 2 weighted images must be taken into consideration especially in determination of the border of affected bone. (author)

  7. Disruptive chemical doping in a ferritin-based iron oxide nanoparticle to decrease r2 and enhance detection with T1-weighted MRI.

    Science.gov (United States)

    Clavijo Jordan, M Veronica; Beeman, Scott C; Baldelomar, Edwin J; Bennett, Kevin M

    2014-01-01

    Inorganic doping was used to create flexible, paramagnetic nanoparticle contrast agents for in vivo molecular magnetic resonance imaging (MRI) with low transverse relaxivity (r2). Most nanoparticle contrast agents formed from superparamagnetic metal oxides are developed with high r2. While sensitive, they can have limited in vivo detection due to a number of constraints with T2 or T2*-weighted imaging. T1-weighted imaging is often preferred for molecular MRI, but most T1-shortening agents are small chelates with low metal payload or are nanoparticles that also shorten T2 and limit the range of concentrations detectable with T1-weighting. Here we used tungsten and iron deposition to form doped iron oxide crystals inside the apoferritin cavity to form a WFe nanoparticle with a disordered crystal and un-coupled atomic magnetic moments. The atomic magnetic moments were thus localized, resulting in a principally paramagnetic nanoparticle. The WFe nanoparticles had no coercivity or saturation magnetization at 5 K and sweeping up to ± 20,000 Oe, while native ferritin had a coercivity of 3000 Oe and saturation at ± 20,000 Oe. This tungsten-iron crystal paramagnetism resulted in an increased WFe particle longitudinal relaxivity (r1) of 4870 mm(-1) s(-1) and a reduced transverse relaxivity (r2) of 9076 mm(-1) s(-1) compared with native ferritin. The accumulation of the particles was detected with T1-weighted MRI in concentrations from 20 to 400 nm in vivo, both injected in the rat brain and targeted to the rat kidney glomerulus. The WFe apoferritin nanoparticles were not cytotoxic up to 700 nm particle concentrations, making them potentially important for targeted molecular MRI. Copyright © 2014 John Wiley & Sons, Ltd.

  8. Parametric methods for characterizing myocardial tissue by magnetic resonance imaging (part 2): T2 mapping.

    Science.gov (United States)

    Perea Palazón, R J; Solé Arqués, M; Prat González, S; de Caralt Robira, T M; Cibeira López, M T; Ortiz Pérez, J T

    2015-01-01

    Cardiac magnetic resonance imaging is considered the reference technique for characterizing myocardial tissue; for example, T2-weighted sequences make it possible to evaluate areas of edema or myocardial inflammation. However, traditional sequences have many limitations and provide only qualitative information. Moreover, traditional sequences depend on the reference to remote myocardium or skeletal muscle, which limits their ability to detect and quantify diffuse myocardial damage. Recently developed magnetic resonance myocardial mapping techniques enable quantitative assessment of parameters indicative of edema. These techniques have proven better than traditional sequences both in acute cardiomyopathy and in acute ischemic heart disease. This article synthesizes current developments in T2 mapping as well as their clinical applications and limitations. Copyright © 2014 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  9. Optimisation of T{sub 2}{sup *}-weighted MRI for the detection of small veins in multiple sclerosis at 3 T and 7 T

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Jennifer Elizabeth, E-mail: jennifer.dixon@nottingham.ac.uk [Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Simpson, Ashley, E-mail: ashley.simpson@nhs.net [Academic Division of Clinical Neurology, University of Nottingham, Queen' s Medical Centre, Nottingham, NG7 2UH (United Kingdom); Mistry, Niraj, E-mail: niraj.mistry@nottingham.ac.uk [Academic Division of Clinical Neurology, University of Nottingham, Queen' s Medical Centre, Nottingham, NG7 2UH (United Kingdom); Evangelou, Nikos, E-mail: nikos.evangelou@nuh.nhs.uk [Academic Division of Clinical Neurology, University of Nottingham, Queen' s Medical Centre, Nottingham, NG7 2UH (United Kingdom); Morris, Peter Gordon, E-mail: peter.morris@nottingham.ac.uk [Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, NG7 2RD (United Kingdom)

    2013-05-15

    T{sub 2}{sup *}-weighted magnetic resonance imaging at 7 T has recently been shown to allow differentiation between white-matter multiple sclerosis lesions and asymptomatic white-matter lesions, by the presence or absence of a detectable central blood vessel. The aim of the present work is to improve the technique by increasing the sensitivity to veins at both 3 T and 7 T, and to assess the benefit of ultra-high-field imaging. Signal-to-noise ratio (SNR) measurements and simulations are used to compare the sensitivity of magnitude T{sub 2}{sup *}-weighted and susceptibility-weighted images for the detection of small veins (<1 pixel in diameter), both with and without the use of gadolinium. The simulations are used to predict the optimal scanning parameters in order to increase the sensitivity to these veins at both field strengths, and to reduce the inherent dependence on vessel orientation. The sensitivities of the sequences at both field strengths are compared, theoretically and experimentally, in order to quantify the benefit of imaging at ultra-high-field. Subjects with multiple sclerosis (MS) are scanned at both field strengths, using the optimised sequence parameters, as well as those used in previously published work, and the optimisation is shown to improve the detection of veins within lesions.

  10. T2-weighted liver MRI using the multiVane technique at 3T: Comparison with conventional T2-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kyung A [Dept. of Radiology, Myongji Hospital, Seonam University College of Medicine, Goyang (Korea, Republic of); Kim, Young Kon; Jeong, Woo Kyoung; Choi, Dong Il; Lee, Won Jae [Dept. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Eun Ju [Philips Healthcare Korea, Philips, Seoul (Korea, Republic of); Jung, Sin Ho; Baek, Sun Young [Biostatistics and Clinical Epidemiology Center, Samsung Medical Center, Seoul (Korea, Republic of)

    2015-10-15

    To assess the value of applying MultiVane to liver T2-weighted imaging (T2WI) compared with conventional T2WIs with emphasis on detection of focal liver lesions. Seventy-eight patients (43 men and 35 women) with 86 hepatic lesions and 20 pancreatico-biliary diseases underwent MRI including T2WIs acquired using breath-hold (BH), respiratory-triggered (RT), and MultiVane technique at 3T. Two reviewers evaluated each T2WI with respect to artefacts, organ sharpness, and conspicuity of intrahepatic vessels, hilar duct, and main lesion using five-point scales, and made pairwise comparisons between T2WI sequences for these categories. Diagnostic accuracy (Az) and sensitivity for hepatic lesion detection were evaluated using alternative free-response receiver operating characteristic analysis. MultiVane T2WI was significantly better than BH-T2WI or RT-T2WI for organ sharpness and conspicuity of intrahepatic vessels and main lesion in both separate reviews and pairwise comparisons (p < 0.001). With regard to motion artefacts, MultiVane T2WI or BH-T2WI was better than RT-T2WI (p < 0.001). Conspicuity of hilar duct was better with BH-T2WI than with MultiVane T2WI (p = 0.030) or RT-T2WI (p < 0.001). For detection of 86 hepatic lesions, sensitivity (mean, 97.7%) of MultiVane T2WI was significantly higher than that of BH-T2WI (mean, 89.5%) (p = 0.008) or RT-T2WI (mean, 84.9%) (p = 0.001). Applying the MultiVane technique to T2WI of the liver is a promising approach to improving image quality that results in increased detection of focal liver lesions compared with conventional T2WI.

  11. Gadolinium-enhanced T{sub 1}-weighted MR urography versus T{sub 2}-weighted (HASTE) MR urography in children; Kontrastangehobene T{sub 1}-gewichtete MR-Urographie versus T{sub 2}-gewichtete (HASTE) MR-Urographie im Kindesalter

    Energy Technology Data Exchange (ETDEWEB)

    Staatz, G.; Nolte-Ernsting, C.C.A.; Haage, P.; Tacke, J.; Guenther, R.W. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Rohrmann, D. [Technische Hochschule Aachen (Germany). Urologische Klinik; Stollbrink, C. [Technische Hochschule Aachen (Germany). Kinderklinik

    2001-11-01

    Purpose: To evaluate gadolinium-enhanced T{sub 1}-weighted excretory MR urography (EMRU) versus T{sub 2}-weighted (HASTE) MR urography in children with upper urinary tract abnormalities. Patients and Methods: In a prospective study 63 children, aged from 3 weeks to 15 years, underwent MR urography in a 1.5-T scanner. Before and after an intravenous injection of 0.05 mg/kg body weight of furosemide, respiratory-triggered HASTE images were obtained for T{sub 2}-weighted MR urography. EMRU was performed subsequent to i.v. gadolinium injection with respiratory-gated, coronal 3D-gradient-echo sequences. Results: Compared to T{sub 2}-weighted (HASTE) MR urography, gadolinium-enhanced MR urography revealed a superior diagnostic accuracy in non-dilated collecting systems (horseshoe kidneys, ectopic kidneys, duplex systems, single ectopic ureters, ureteroceles). EMRU and T{sub 2}-weighted (HASTE) MRU turned out to be equivalent in the assessment of obstructed but normal functioning upper urinary tracts (UPJ obstructions, megaureters). Non-functioning dilated collecting systems and multicystic dysplastic kidneys were best visualized with use of T{sub 2}-weighted (HASTE) MR urography. Conclusion: Respiratory-gated gadolinium-enhanced T{sub 1}-weighted MRU allows accurate evaluation of most upper urinary tract abnormalities. T{sub 2}-weighted (HASTE) MRU complements GMRU in the evaluation of non-functioning renal units and cystic disease of the kidneys. (orig.) [German] Ziel: Vergleich der kontrastangehobenen T{sub 1}-gewichteten MR-Urographie mit der T{sub 2}-gewichteten (HASTE) MR-Urographie bei Kindern mit Anomalien des oberen Harntraktes. Methoden: In einer prospektiven Studie wurde bei 63 Kindern (3 Wo. - 15J.) eine MR-Urographie (MRU) in einem 1,5-Tesla-Magneten durchgefuehrt. Die T{sub 2}-gewichtete MRU erfolgte vor und nach intravenoeser Injektion von 0,05 mg/kg KG Furosemid mit atemgetriggerten HASTE-Sequenzen. Fuer die T{sub 1}-gewichtete MRU wurden nach

  12. High-field magnetization studies of U2T2Sn (T=Co, Ir, Pt) compounds

    International Nuclear Information System (INIS)

    Prokes, K.; Nakotte, H.; de Boer, F.R.

    1995-01-01

    High-field magnetization measurements at 4.2 K on U 2 T 2 Sn (T = Co, Ir and Pt) compounds have been performed on free and fixed powders up to 57 T. An antiferromagnetic ground state of U 2 Pt 2 Sn is corroborated by a metamagnetic transition at 22 T with very small hysteresis going up and down with field. U 2 Co 2 Sn and U 2 Ir 2 Sn show no metamagnetic transition up to 57 T which is in agreement with the non-magnetic ground state of these compounds. In all cases, the maximum applied field is not sufficient to achieve saturation. The short-pulse measurements presented here are compared with previous results obtained in quasi-static fields up to 35 T

  13. The association between Placental T2* measured by MRI in dichorionic twin pregnancies and intertwin birth weight differences

    DEFF Research Database (Denmark)

    Sørensen, Anne Nødgaard Weidemann; Sinding, Marianne Munk; Peters, David Alberg

    ABSTRACT FINAL ID: P22.06 TITLE: The association between Placental T2* measured by MRI in dichorionic twin pregnancies and intertwin birth weight differences AUTHORS (FIRST NAME, LAST NAME): Anne Sørensen1, 2, Marianne Sinding1, David Peters3, Jens B. Frøkjær4, 2, Astrid Petersen6, Niels Uldbjerg5...... with an increased risk of adverse neonatal outcome, and new methods to predict the intertwin birth weight difference are highly clinical relevant. The Magnetic Resonance Imaging (MRI) variable placentalT2* reflects placental oxygenation and thereby placental function. Therefore, we aimed to investigate...... the association between the intertwin placental T2* difference and the intertwin birth weight difference Methods: A total of 21 dichorionic twin pregnancies (gestational age 20.1 – 34.1 weeks) were included in this study and placental T2* was measured using a gradient recalled echo MRI sequence with readout at 16...

  14. Cerebral and meningeal manifestations of AIDS: comparison of plain T2-weighted images and Gd-DTPA enhanced T1-weighted images in 105 patients

    International Nuclear Information System (INIS)

    Jochens, R.; Henkes, H.; Steinkamp, H.J.; Terstegge, K.; Hosten, N.; Ruf, B.; Schoerner, W.

    1994-01-01

    The purpose of the present study was to evaluate the potential of T1-weighted Gd-DTPA enhanced MR imaging in the diagnosis of cerebral manifestations of AIDS. 105 patients with AIDS were imaged with plain T2-weighted images as well as with Gd-DTPA enhanced T1-weighted pulse sequences. Our study revealed comparable sensitivities in the detection of morphological changes as shown on plain T2-weighted images and Gd-DTPA enhanced T1-weighted images in 55% of patients (normal and pathologic findings). Plain T2-weighted images were superior in 28.5% and provided significantly better results in 8.5% of patients. Gd-DTPA enhanced T1-weighted images were superior in only 5% cases and revealed significantly better results in 3%. As a result, T2-weighted plain images were superior in approximately 40% of patients concerning detection of morphologic changes. In almost 10% of patients with parechymal and meningeal lesions, Gd-DTPA enhanced T1-weighted images, however, were superior or even significantly better compared to T2-weighted plain images. The detection of morphologic changes in MR imaging can be further increased with Gd-DTPA. With regard to differential diagnosis and diesease activity, plain T2-weighted images and Gd-DTPA enhanced T1-weighted images revealed comparable results in 42% of patients (normal and pathologic findings). T2-weighted plain images were superior in 2% of cases whereas Gd-DTPA enhanced T1-weighted images were superior in as much as 56% of patient. MR imaging enhanced with Gd-DTPA yielded additional information on disease activity in 73% of patients with pathologic findings in the cerebral parechyma and the meninges. The surplus of information also refers to the etiology of cerebral pathology and differential diagnosis. Because of the frequency of cerebral manifestations in AIDS, early diagnosis for initiation of therapy and follow-up studies to monitor therapy are crucial. (orig./MG) [de

  15. Role of diffusion-weighted magnetic resonance imaging in the diagnosis of extrahepatic cholangiocarcinoma

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    AIM: To determine the clinical value of diffusion-weight- ed imaging (DWI) for the diagnosis of extrahepatic cholangiocarcinoma (EHCC) by comparing the diagnostic sensitivity of DWI and magnetic resonance cholan-giopancreatography (MRCP). METHODS: Magnetic resonance imaging examination was performed in 56 patients with suspected EHCC. T1- weighted imaging, T2-weighted imaging, MRCP and DWI sequence, DWI using single-shot spin-echo echoplanar imaging sequence with different b values (100, 300, 500, 800 and 1...

  16. Evaluation of neonatal brain myelination using the T1- and T2-weighted MRI ratio.

    Science.gov (United States)

    Soun, Jennifer E; Liu, Michael Z; Cauley, Keith A; Grinband, Jack

    2017-09-01

    To validate the T1- and T2-weighted (T1w/T2w) MRI ratio technique in evaluating myelin in the neonatal brain. T1w and T2w MR images of 10 term neonates with normal-appearing brain parenchyma were obtained from a single 1.5 Tesla MRI and retrospectively analyzed. T1w/T2w ratio images were created with a postprocessing pipeline and qualitatively compared with standard clinical sequences (T1w, T2w, and apparent diffusion coefficient [ADC]). Quantitative assessment was also performed to assess the ratio technique in detecting areas of known myelination (e.g., posterior limb of the internal capsule) and very low myelination (e.g., optic radiations) using linear regression analysis and the Michelson Contrast equation, a measure of luminance contrast intensity. The ratio image provided qualitative improvements in the ability to visualize regional variation in myelin content of neonates. Linear regression analysis demonstrated a significant inverse relationship between the ratio intensity values and ADC values in the posterior limb of the internal capsule and the optic radiations (R 2  = 0.96 and P ratio images were 1.6 times higher than T1w, 2.6 times higher than T2w, and 1.8 times higher than ADC (all P ratio improved visualization of the corticospinal tract, one of the earliest myelinated pathways. The T1w/T2w ratio accentuates contrast between myelinated and less myelinated structures and may enhance our diagnostic ability to detect myelination patterns in the neonatal brain. 2 Technical Efficacy: Stage2 J. MAGN. RESON. IMAGING 2017;46:690-696. © 2016 International Society for Magnetic Resonance in Medicine.

  17. Assessment of T2- and T1-weighted MRI brain lesion load in patients with subcortical vascular encephalopathy

    International Nuclear Information System (INIS)

    Gass, A.; Oster, M.; Cohen, S.; Daffertshofer, M.; Schwartz, A.; Hennerici, M.G.

    1998-01-01

    Previous cross-sectional studies in patients with subcortical vascular encephalopathy (SVE) have shown little or no correlation between brain lesion load and clinical disability, which could be due to the low specificity of T2-weighted MRI. Recent studies have indicated that T1-weighted MRI may be more specific than T2-weighted MRI for severe tissue destruction. We studied 37 patients with a diagnosis of SVE and 11 normal controls with standardised T1- and T2-weighted MRI. All patients underwent detailed clinical assessment including a neuropsychological test battery and computerised gait analysis. Both the T2- and T1-weighted total MRI lesion loads different between patients and controls different, particularly T1. The ratio of T2-/T1-weighted lesion load was lower in controls than in patients. There was no overall correlation of T1- or T2-weighted lesion load with clinical disability, but group comparison of patients with severe and mild clinical deficits showed different lesion loads. We suggest that T1- and T2-weighted MRI lesion loads demonstrate relevant structural abnormality in patients with SVE. (orig.)

  18. Combined use of T2-weighted and diffusion-weighted 3-T MR imaging for differentiating uterine sarcomas from benign leiomyomas

    International Nuclear Information System (INIS)

    Namimoto, Tomohiro; Yamashita, Yasuyuki; Awai, Kazuo; Nakaura, Takeshi; Yanaga, Yumi; Hirai, Toshinori; Saito, Tetsuo; Katabuchi, Hidetaka

    2009-01-01

    The objective of our study was to compare diffusion-weighted imaging (DWI) alone and DWI combined with T2-weighted MRI for the differentiation of uterine sarcomas from benign leiomyomas. T2-weighted imaging and DWI were performed in 103 patients with 103 myometrial tumours, including 8 uterine sarcomas and 95 benign leiomyomas on 3-T MR imaging. The signal intensity (SI) of the tumour on T2-weighted images was quantified as the tumour-myometrium contrast ratio (TCR) by using the following formula: (SI tumour - SI myometrium )/SI myometrium . The TCR or apparent diffusion coefficient (ADC) value alone and then the ADC value combined with T2-weighted imaging were evaluated for differentiation between sarcomas and leiomyomas. The mean ADC value of sarcomas was 0.86 ± 0.11 x 10 -3 m 2 /s, which was significantly lower than that of leiomyomas 1.18 ± 0.24 x 10 -3 m 2 /s; however, there was a substantial overlap. The mean TCR of sarcomas was 0.66 ± 0.71, which was significantly higher than that of the leiomyomas, -0.37 ± 0.34; however, again, there was a considerable overlap. When ADC was less than 1.05 x 10 -3 mm 2 /s and TCR was greater than 0 this condition was considered to confirm a sarcoma; a combination of ADC and TCR achieved a significant improvement without any overlap between sarcomas and leiomyomas (sensitivity 100%, specificity 100%). Our preliminary results indicate that combined DWI and T2-weighted MR imaging is better than DWI alone in the differentiation of uterine sarcomas from benign leiomyomas. (orig.)

  19. Usefulness of magnetic resonance cholangiography and additional T2-weighted axial image in evaluating focaI intrahepatic ductal dilatation

    International Nuclear Information System (INIS)

    Park, Yeong Mi; Cha, Sung Sook; Lee, Jong Yuk

    2004-01-01

    To evaluate the value of MR cholangiography (MRC) and MRC with additional T2-weighted axial imaging for evaluating the cause and determining the therapeutic plan in patients with a focal dilatation of the intrahepatic bile ducts(IHBD). Forty nine patients (male, 27; female, 22; age range, 12-72 (mean, 51) years) with a focal intrahepatic ductal dilatation confirmed surgically and pathologically (lobectomy, 34; biopsy, 7; surgical finding and T-tube cholangiography, 7; percutaneous transhepatic biliary drainage with bile cytology, 1) underwent MRC and T2-weighted axial imaging. The MRC were obtained in one of two ways (a single slab or multislice acquisition under chemical fat saturation) using RARE (31 patients, source images and single slice images), or TSE (18 patients, source images and MIP reconstruction images). Two radiologists reviewed the MRC images alone, and the MRC images with the T2-weighted axial images. A diagnosis was determined by consensus. In 37 out of 49 patients, the causes of a bile duct dilation were benign diseases (IHBD stones in 33 cases, liver abscesses with IHBD stones in three cases, one inflammatory pseudotumor). Twelve patients had cholangiocarcinomas (mass-forming type in seven cases, intraductal type in three cases, and periductaI infiltrating type in two cases). A correct diagnosis was confirmed in 47 out of 49 cases(96.0%), i.e. all the 37 benign lesions and 10 out of 12 malignant lesions. The addition of the T2-weighted axial image to the MRC did not alter the diagnosis of the causes of the focal intrahepatic ductal dilatation, but was helpful in 10 cases (20.4%). Nine cases (7 cholangiocarcinomas and 2 abscesses), in which MRC showed masses, were visualized more definitely on the additional T2-weighted axial images to the MRC than on the MRC alone. The remaining cases were hepatolithiasis, where stones could be easily differentiated from air by the air-fluid level on the axial images. MRC is a good diagnostic modality for

  20. Registration of T2-weighted and diffusion-weighted MR images of the prostate: comparison between manual and landmark-based methods

    Science.gov (United States)

    Peng, Yahui; Jiang, Yulei; Soylu, Fatma N.; Tomek, Mark; Sensakovic, William; Oto, Aytekin

    2012-02-01

    Quantitative analysis of multi-parametric magnetic resonance (MR) images of the prostate, including T2-weighted (T2w) and diffusion-weighted (DW) images, requires accurate image registration. We compared two registration methods between T2w and DW images. We collected pre-operative MR images of 124 prostate cancer patients (68 patients scanned with a GE scanner and 56 with Philips scanners). A landmark-based rigid registration was done based on six prostate landmarks in both T2w and DW images identified by a radiologist. Independently, a researcher manually registered the same images. A radiologist visually evaluated the registration results by using a 5-point ordinal scale of 1 (worst) to 5 (best). The Wilcoxon signed-rank test was used to determine whether the radiologist's ratings of the results of the two registration methods were significantly different. Results demonstrated that both methods were accurate: the average ratings were 4.2, 3.3, and 3.8 for GE, Philips, and all images, respectively, for the landmark-based method; and 4.6, 3.7, and 4.2, respectively, for the manual method. The manual registration results were more accurate than the landmark-based registration results (p < 0.0001 for GE, Philips, and all images). Therefore, the manual method produces more accurate registration between T2w and DW images than the landmark-based method.

  1. 3D isotropic T2-weighted fast spin echo (VISTA) versus 2D T2-weighted fast spin echo in evaluation of the calcaneofibular ligament in the oblique coronal plane.

    Science.gov (United States)

    Park, H J; Lee, S Y; Choi, Y J; Hong, H P; Park, S J; Park, J H; Kim, E

    2017-02-01

    To investigate whether the image quality of three-dimensional (3D) volume isotropic fast spin echo acquisition (VISTA) magnetic resonance imaging (MRI) of the calcaneofibular ligament (CFL) view is comparable to that of 2D fast spin echo T2-weighted images (2D T2 FSE) for the evaluation of the CFL, and whether 3D VISTA can replace 2D T2 FSE for the evaluation of CFL injuries. This retrospective study included 76 patients who underwent ankle MRI with CFL views of both 2D T2 FSE MRI and 3D VISTA. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of both techniques were measured. The anatomical identification score and diagnostic performances were evaluated by two readers independently. The diagnostic performances of 3D VISTA and 2D T2 FSE were analysed by sensitivity, specificity, and accuracy for diagnosing CFL injury with reference standards of surgically or clinically confirmed diagnoses. Surgical correlation was performed in 29% of the patients, and clinical examination was used in those who did not have surgery (71%). The SNRs and CNRs of 3D VISTA were significantly higher than those of 2D T2 FSE. The anatomical identification scores on 3D VISTA were inferior to those on 2D T2 FSE, and the differences were statistically significant (pT2 FSE for the anatomical evaluation of CFL, 3D VISTA has a diagnostic performance comparable to that of 2D T2 FSE for the diagnosis of CFL injuries. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  2. Differentiation between simple cyst and hepatic hemangioma utilizing T2-weighted magnetic resonance imaging with gradient-echo (b-FFE) technique

    International Nuclear Information System (INIS)

    Burim, Carolina Valente; D'Ippolito, Giuseppe; Pecci Neto, Luiz; Torlai, Fabiola Goda; Tiferes, Dario Ariel

    2008-01-01

    Objective: to establish the role of MRI T2-weighted sequences in the differentiation between simple cysts and hepatic hemangiomas. Materials and methods: a double-blinded, prospective, observational, cross sectional study evaluated 52 patients with 91 hepatic lesions (34 simple cysts and 57 hemangiomas) submitted to abdominal magnetic resonance imaging. The combined analysis of all sequences was considered as the golden-standard. TSE sequences with long echo trains and b-FFE sequences were subjectively analyzed by two independent observers for differentiating cysts from hemangiomas. The kappa test (κ) was utilized in the analysis of the methods accuracy and inter- and intra-observer agreement (p * ). Results: cysts and hemangiomas dimensions ranged respectively between 0.5 and 6.5 cm (mean 1.89 cm), and 0.8 and 11 cm (mean = 2.62 cm). The analysis of the sequences with long-TE and the golden-standard demonstrated a non-statistically significant agreement (k: 0.00-0.10). The agreement between the evaluation of the b-FFE sequence and the golden-standard ranged from substantial (κ: 0.62-0.71) to almost perfect (κ: 0.86) for both observers. The inter- and intra-observer agreement for the b-FFE sequence ranged from substantial (κ: 0.62-0.70) to almost perfect (κ: 0.85-0.91). Conclusion: T2-weighted images acquired with the b-FFE technique present a high accuracy and reproducibility in the differentiation between cysts and hepatic hemangiomas. (author)

  3. 3D Fast Spin Echo T2-weighted Contrast for Imaging the Female Cervix

    Science.gov (United States)

    Vargas Sanchez, Andrea Fernanda

    Magnetic Resonance Imaging (MRI) with T2-weighted contrast is the preferred modality for treatment planning and monitoring of cervical cancer. Current clinical protocols image the volume of interest multiple times with two dimensional (2D) T2-weighted MRI techniques. It is of interest to replace these multiple 2D acquisitions with a single three dimensional (3D) MRI acquisition to save time. However, at present the image contrast of standard 3D MRI does not distinguish cervical healthy tissue from cancerous tissue. The purpose of this thesis is to better understand the underlying factors that govern the contrast of 3D MRI and exploit this understanding via sequence modifications to improve the contrast. Numerical simulations are developed to predict observed contrast alterations and to propose an improvement. Improvements of image contrast are shown in simulation and with healthy volunteers. Reported results are only preliminary but a promising start to establish definitively 3D MRI for cervical cancer applications.

  4. Magnetic resonance imaging of the cranial nerves in the posterior fossa: a comparative study of t2-weighted spin-echo sequences at 1.5 and 3.0 tesla.

    Science.gov (United States)

    Fischbach, F; Müller, M; Bruhn, H

    2008-04-01

    High-field magnetic resonance imaging (MRI) at 3.0 Tesla (T) is rapidly gaining clinical acceptance. Whether doubling of the field strength of 1.5T and the subsequent increase in signal-to-noise ratio (SNR) leads to a significant improvement of image quality is not automatically given. To evaluate the depiction of fine anatomic detail in the posterior fossa, focusing on brain nerves, on T2-weighted imaging, and to define the potential advantage of imaging at 3.0T versus 1.5T. In total, 10 brainstem nerve pairs of 12 volunteers were identified on T2-weighted MR images of 2- and 5-mm section thickness acquired at 1.5T and 3.0T. The MR images were compared for each subject at both field strengths by three independent readers who rated image quality according to depiction of anatomic detail and contrast by using a rating scale. In general, MR images at 3.0T were considered more conspicuous and less noisy than images at 1.5T. The SNR value measured was almost doubled. With respect to structural identification and contrast according to the rating scale, observer scores were significantly improved both for standard imaging with 5-mm sections and high-resolution imaging with 2-mm sections at 3.0T. Direct comparison revealed a significant increase for evaluated image quality criteria and the number of nerves detected. The comparison revealed a clear advantage in favor of T2-weighted MRI at 3.0T vs. 1.5T in depicting the roots and course of brain nerves in the posterior fossa.

  5. T2-Weighted Dixon Turbo Spin Echo for Accelerated Simultaneous Grading of Whole-Body Skeletal Muscle Fat Infiltration and Edema in Patients With Neuromuscular Diseases.

    Science.gov (United States)

    Schlaeger, Sarah; Klupp, Elisabeth; Weidlich, Dominik; Cervantes, Barbara; Foreman, Sarah C; Deschauer, Marcus; Schoser, Benedikt; Katemann, Christoph; Kooijman, Hendrik; Rummeny, Ernst J; Zimmer, Claus; Kirschke, Jan S; Karampinos, Dimitrios C

    2018-04-02

    The assessment of fatty infiltration and edema in the musculature of patients with neuromuscular diseases (NMDs) typically requires the separate performance of T1-weighted and fat-suppressed T2-weighted sequences. T2-weighted Dixon turbo spin echo (TSE) enables the generation of T2-weighted fat- and water-separated images, which can be used to assess both pathologies simultaneously. The present study examines the diagnostic performance of T2-weighted Dixon TSE compared with the standard sequences in 10 patients with NMDs and 10 healthy subjects. Whole-body magnetic resonance imaging was performed including T1-weighted Dixon fast field echo, T2-weighted short-tau inversion recovery, and T2-weighted Dixon TSE. Fatty infiltration and intramuscular edema were rated by 2 radiologists using visual semiquantitative rating scales. To assess intermethod and interrater agreement, weighted Cohen's κ coefficients were calculated. The ratings of fatty infiltration showed high intermethod and high interrater agreement (T1-weighted Dixon fast field echo vs T2-weighted Dixon TSE fat image). The evaluation of edematous changes showed high intermethod and good interrater agreement (T2-weighted short-tau inversion recovery vs T2-weighted Dixon TSE water image). T2-weighted Dixon TSE imaging is an alternative for accelerated simultaneous grading of whole-body skeletal muscle fat infiltration and edema in patients with NMDs.

  6. High-resolution T{sub 2}-weighted cervical cancer imaging: a feasibility study on ultra-high-field 7.0-T MRI with an endorectal monopole antenna

    Energy Technology Data Exchange (ETDEWEB)

    Hoogendam, Jacob P.; Verheijen, Rene H.M.; Zweemer, Ronald P. [University Medical Centre Utrecht, Department of Gynaecological Oncology, UMC Utrecht Cancer Centre, PO Box 85500, Utrecht (Netherlands); Kalleveen, Irene M.L.; Castro, Catalina S.A. de; Raaijmakers, Alexander J.E.; Bosch, Maurice A.A.J. van den; Klomp, Dennis W.J.; Veldhuis, Wouter B. [University Medical Centre Utrecht, Department of Radiology, Utrecht (Netherlands)

    2017-03-15

    We studied the feasibility of high-resolution T{sub 2}-weighted cervical cancer imaging on an ultra-high-field 7.0-T magnetic resonance imaging (MRI) system using an endorectal antenna of 4.7-mm thickness. A feasibility study on 20 stage IB1-IIB cervical cancer patients was conducted. All underwent pre-treatment 1.5-T MRI. At 7.0-T MRI, an external transmit/receive array with seven dipole antennae and a single endorectal monopole receive antenna were used. Discomfort levels were assessed. Following individualised phase-based B{sub 1} {sup +} shimming, T{sub 2}-weighted turbo spin echo sequences were completed. Patients had stage IB1 (n = 9), IB2 (n = 4), IIA1 (n = 1) or IIB (n = 6) cervical cancer. Discomfort (ten-point scale) was minimal at placement and removal of the endorectal antenna with a median score of 1 (range, 0-5) and 0 (range, 0-2) respectively. Its use did not result in adverse events or pre-term session discontinuation. To demonstrate feasibility, T{sub 2}-weighted acquisitions from 7.0-T MRI are presented in comparison to 1.5-T MRI. Artefacts on 7.0-T MRI were due to motion, locally destructive B{sub 1} interference, excessive B{sub 1} under the external antennae and SENSE reconstruction. High-resolution T{sub 2}-weighted 7.0-T MRI of stage IB1-IIB cervical cancer is feasible. The addition of an endorectal antenna is well tolerated by patients. (orig.)

  7. Gadolinium-DTPA enhancement of VX-2 carcinoma of the rabbit kidney on Tl weighted magnetic resonance images

    International Nuclear Information System (INIS)

    Yancey, J.M.; Ackerman, N.; Kaude, J.V.; Googe, R.E.; Fitzsimmons, J.R.; Scott, K.N.; Mancuso, A.A.; Hackett, R.L.; Hager, D.A.; Caballero, S.; Florida Univ., Gainesville

    1987-01-01

    Experimental renal carcinoma was induced by percutaneous injection of VX-2 carcinoma cells into the left kidney in New Zealand white rabbits. Magnetic resonance imaging (MRI) was performed at 0.15 T before and after intravenous injection of 0.3 mmol gadolinium-DTPA (Gd-DTPA) per kg body weight. Gd-DTPA enhanced the tumors by increasing the signal intensity on T1 weighted images. The enhancement was evident immediately after Gd-DTPA injection, increasing during the observation time of 30 minutes. Histologically the areas of enhancement corresponded well to the viable tumor tissue. (orig.)

  8. Comparative study of image quality between axial T2-weighted BLADE and turbo spin-echo MRI of the upper abdomen on 3.0 T.

    Science.gov (United States)

    Zhang, Lin; Tian, ChunMei; Wang, PeiYuan; Chen, Liang; Mao, XiJin; Wang, ShanShan; Wang, Xu; Dong, JingMin; Wang, Bin

    2015-09-01

    To compare image quality of turbo spin-echo (TSE) with BLADE [which is also named periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER)] on magnetic resonance imaging (MRI) for upper abdomen. This study involved the retrospective evaluation of 103 patients (63 males, 40 females; age range 19-76 years; median age 53.8 years) who underwent 3.0 T MRI with both conventional TSE T2-weighted imaging (T2WI) and BLADE TSE T2WI. Two radiologists assessed respiratory motion, gastrointestinal peristalsis, and vascular pulsation artifacts, as well as the sharpness of the liver and pancreas edges. Scores for all magnetic resonance (MR) images were recorded. Wilcoxon's rank test was used to compare hierarchical data. Cohen's kappa coefficient was adopted to analyze interobserver consistency. Compared to TSE T2WI, BLADE TSE T2WI reduced all of the examined motion artifacts and increased the sharpness of the liver and pancreas edges (all P image quality.

  9. Endometrial cancer: preoperative staging using three-dimensional T2-weighted turbo spin-echo and diffusion-weighted MR imaging at 3.0 T: a prospective comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Hori, Masatoshi; Kim, Tonsok; Onishi, Hiromitsu; Nakamoto, Atsushi; Tomiyama, Noriyuki [Osaka University Graduate School of Medicine, Department of Radiology, Suita, Osaka (Japan); Imaoka, Izumi; Kagawa, Yuki; Murakami, Takamichi [Kinki University School of Medicine, Department of Radiology, Osaka (Japan); Ueguchi, Takashi; Tatsumi, Mitsuaki [Osaka University Hospital, Department of Radiology, Osaka (Japan); Enomoto, Takayuki [Osaka University Graduate School of Medicine, Department of Obstetrics and Gynecology, Osaka (Japan); Niigata University School of Medicine, Department of Obstetrics and Gynecology, Niigata (Japan); Kimura, Tadashi [Osaka University Graduate School of Medicine, Department of Obstetrics and Gynecology, Osaka (Japan)

    2013-08-15

    To prospectively assess the efficacy of 3-T magnetic resonance (MR) imaging using the three-dimensional turbo spin-echo T2-weighted and diffusion-weighted technique (3D-TSE/DW) compared with that of conventional imaging using the two-dimensional turbo spin-echo T2-weighted and dynamic contrast-enhanced technique (2D-TSE/DCE) for the preoperative staging of endometrial cancer, with pathological analysis as the reference standard. Seventy-one women with endometrial cancer underwent MR imaging using 3D-TSE/DW (b = 1,000 s/mm{sup 2}) and 2D-TSE/DCE. Two radiologists independently assessed the two imaging sets. Accuracy, sensitivity, and specificity for staging were analysed with the McNemar test; the areas under the receiver operating characteristic curve (Az) were compared with a univariate z-score test. The results for assessing deep myometrial invasion, accuracy, sensitivity, specificity and Az, respectively, were as follows: 3D-TSE/DW - observer 1, 87 %, 95 %, 85 % and 0.96; observer 2, 92 %, 84 %, 94 % and 0.95; 2D-TSE/DCE - observer 1, 80 %, 79 %, 81 % and 0.89; observer 2, 86 %, 84 %, 87 % and 0.86. Most of the values were higher with 3D-TSE/DW without significant differences (P > 0.12). For assessing cervical stromal invasion, there were no significant differences in those values for both observers (P > 0.6). Accuracy of 3D-TSE/DW was at least equivalent to that of the conventional technique for the preoperative assessment of endometrial cancer. (orig.)

  10. Detection of hypoxic-ischemic brain injury with 3D-enhanced T2* weighted angiography (ESWAN) imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gang, QiangQiang, E-mail: rousikang@163.com; Zhang, Jianing, E-mail: 1325916060@qq.com; Hao, Peng, E-mail: 1043600590@qq.com; Xu, Yikai, E-mail: yikaivip@163.com

    2013-11-01

    Objective: To demonstrate the use of 3D-enhanced T2* weighted angiography (ESWAN) imaging for the observation and quantification of the evolution of brain injury induced by a recently developed model of hypoxic-ischemic brain injury (HI/R) in neonatal piglets. Methods: For these experiments, newborn piglets were subjected to HI/R injury, during which ESWAN scanning was performed, followed by H and E staining and immunohistochemistry of AQP-4 expression. Results: In the striatum, values from T2* weighted magnetic resonance imaging (MRI) increased and reached their highest level at 3 days post injury, whereas T2* values increased and peaked at 24 h in the subcortical region. The change in T2* values was concordant with brain edema. Phase values in the subcortical border region were not dependent on time post-injury. Magnitude values were significantly different from the control group, and increased gradually over time in the subcortical border region. Susceptibility-weighted images (SWI) indicated small petechial hemorrhages in the striatum and thalamus, as well as dilated intramedullary veins. Conclusion: SWI images can be used to detect white and gray matter microhemorrhages and dilated intramedullary veins. The T2*, phase, and magnitude map can also reflect the development of brain injury. Our data illustrate that ESWAN imaging can increase the diagnostic sensitivity and specificity of MRI in neonatal hypoxic-ischemic encephalopathy.

  11. Detection of hypoxic-ischemic brain injury with 3D-enhanced T2* weighted angiography (ESWAN) imaging

    International Nuclear Information System (INIS)

    Gang, QiangQiang; Zhang, Jianing; Hao, Peng; Xu, Yikai

    2013-01-01

    Objective: To demonstrate the use of 3D-enhanced T2* weighted angiography (ESWAN) imaging for the observation and quantification of the evolution of brain injury induced by a recently developed model of hypoxic-ischemic brain injury (HI/R) in neonatal piglets. Methods: For these experiments, newborn piglets were subjected to HI/R injury, during which ESWAN scanning was performed, followed by H and E staining and immunohistochemistry of AQP-4 expression. Results: In the striatum, values from T2* weighted magnetic resonance imaging (MRI) increased and reached their highest level at 3 days post injury, whereas T2* values increased and peaked at 24 h in the subcortical region. The change in T2* values was concordant with brain edema. Phase values in the subcortical border region were not dependent on time post-injury. Magnitude values were significantly different from the control group, and increased gradually over time in the subcortical border region. Susceptibility-weighted images (SWI) indicated small petechial hemorrhages in the striatum and thalamus, as well as dilated intramedullary veins. Conclusion: SWI images can be used to detect white and gray matter microhemorrhages and dilated intramedullary veins. The T2*, phase, and magnitude map can also reflect the development of brain injury. Our data illustrate that ESWAN imaging can increase the diagnostic sensitivity and specificity of MRI in neonatal hypoxic-ischemic encephalopathy

  12. Difference between T sub 1 and T sub 2 weighted MR images in avascular necrosis of the femoral head

    Energy Technology Data Exchange (ETDEWEB)

    Kokubo, Takashi; Yoshikawa, Koki; Itai, Yuzo; Iio, Masahiro; Takatori, Yoshio; Kamogawa, Morihide; Ninomiya, Setsuo [Tokyo Univ. (Japan). Faculty of Medicine

    1990-01-01

    T{sub 1} and T{sub 2} weighted MR images were compared in 32 hips with avascular necrosis, and the difference between them was discussed. In 27 of 32 hips, abnormal low intensity area in the affected femoral head is smaller in T{sub 2} weighted images than in T{sub 1} weighted images. The area of low intensity on T{sub 1} weighted image and high on T{sub 2} weighted image might be granuloma in reactive tissue and surrounding hyperemia. The difference between T{sub 1} and T{sub 2} weighted images must be taken into consideration especially in determination of the border of affected bone. (author).

  13. Clinical characteristics in normal healthy adults with microbleeds on echo-planar gradient-echo T2*-weighted MRI

    International Nuclear Information System (INIS)

    Takahashi, Wakoh; Ide, Michiru; Ohnuki, Tomohide; Takagi, Shigeharu; Shinohara, Yukito

    2004-01-01

    The gradient-echo T 2 * -weighted sequence in magnetic resonance imaging is known to be useful for detecting microbleeds (MBs) in patients with intracranial hemorrhage or lacunar stroke. We investigated the characteristics of apparently healthy adults with MBs but without stroke, employing echo-planar gradient-echo T 2 * -weighted MRI. The subjects were recruited from among 3,537 participants who underwent brain check-ups at the HIMEDIC Imaging Center. Of the 3,537 participants, 3,296 (mean age, 55±11 years) without any history of cerebrovascular disease or apparent focal neurological manifestations were selected for the present study. MBs on echo-planar gradient-echo T 2 * -weighted MRI were observed in 74 (2.2%) of the 3,296 subjects. Of a total of 133 lesions found in these 74 persons, 31 were located in the basal ganglia or cortico-subcortical regions. Thirty were in the deep white matter, 19 in the thalamus, 16 in the cerebellum, and 6 in the brain stem. The subjects with MBs were significantly older than the subjects without MBs, and the mean values for their systolic and diastolic blood pressures were higher than those in the subjects without MBs. Asymptomatic cerebral infarction, periventricular hyperintensity, and deep and subcortical white matter hyperintensity on T 1 - and T 2 -weighted MRI were more frequent in the subjects with MBs, as compared with those without MBs. Asymptomatic cerebral infarction, periventricular hyperintensity, and deep and subcortical white matter hyperintensity on T 1 - and T 2 -weighted MRI were more frequent in the subjects with MBs of the basal ganglia or thalamus than in those with MBs in other regions. MBs on echo-planar gradient-echo T 2 * -weighted MRI were thus relatively rare in apparently healthy adults. However, MBs in the basal ganglia or thalamus are suggested to be closely related to intracerebral microangiopathy. Persons with MBs in such regions should therefore be carefully checked for cerebrovascular risk

  14. Volumetric fat-water separated T2-weighted MRI

    International Nuclear Information System (INIS)

    Vasanawala, Shreyas S.; Sonik, Arvind; Madhuranthakam, Ananth J.; Venkatesan, Ramesh; Lai, Peng; Brau, Anja C.S.

    2011-01-01

    Pediatric body MRI exams often cover multiple body parts, making the development of broadly applicable protocols and obtaining uniform fat suppression a challenge. Volumetric T2 imaging with Dixon-type fat-water separation might address this challenge, but it is a lengthy process. We develop and evaluate a faster two-echo approach to volumetric T2 imaging with fat-water separation. A volumetric spin-echo sequence was modified to include a second shifted echo so two image sets are acquired. A region-growing reconstruction approach was developed to decompose separate water and fat images. Twenty-six children were recruited with IRB approval and informed consent. Fat-suppression quality was graded by two pediatric radiologists and compared against conventional fat-suppressed fast spin-echo T2-W images. Additionally, the value of in- and opposed-phase images was evaluated. Fat suppression on volumetric images had high quality in 96% of cases (95% confidence interval of 80-100%) and were preferred over or considered equivalent to conventional two-dimensional fat-suppressed FSE T2 imaging in 96% of cases (95% confidence interval of 78-100%). In- and opposed-phase images had definite value in 12% of cases. Volumetric fat-water separated T2-weighted MRI is feasible and is likely to yield improved fat suppression over conventional fat-suppressed T2-weighted imaging. (orig.)

  15. Urinary bladder cancer T-staging from T2-weighted MR images using an optimal biomarker approach

    Science.gov (United States)

    Wang, Chuang; Udupa, Jayaram K.; Tong, Yubing; Chen, Jerry; Venigalla, Sriram; Odhner, Dewey; Guzzo, Thomas J.; Christodouleas, John; Torigian, Drew A.

    2018-02-01

    Magnetic resonance imaging (MRI) is often used in clinical practice to stage patients with bladder cancer to help plan treatment. However, qualitative assessment of MR images is prone to inaccuracies, adversely affecting patient outcomes. In this paper, T2-weighted MR image-based quantitative features were extracted from the bladder wall in 65 patients with bladder cancer to classify them into two primary tumor (T) stage groups: group 1 - T stage T2, with primary tumor locally confined to the bladder, and group 2 - T stage T2, with primary tumor locally extending beyond the bladder. The bladder was divided into 8 sectors in the axial plane, where each sector has a corresponding reference standard T stage that is based on expert radiology qualitative MR image review and histopathologic results. The performance of the classification for correct assignment of T stage grouping was then evaluated at both the patient level and the sector level. Each bladder sector was divided into 3 shells (inner, middle, and outer), and 15,834 features including intensity features and texture features from local binary pattern and gray-level co-occurrence matrix were extracted from the 3 shells of each sector. An optimal feature set was selected from all features using an optimal biomarker approach. Nine optimal biomarker features were derived based on texture properties from the middle shell, with an area under the ROC curve of AUC value at the sector and patient level of 0.813 and 0.806, respectively.

  16. Seminal vesicle invasion in prostate cancer: prediction with combined T2-weighted and diffusion-weighted MR imaging

    International Nuclear Information System (INIS)

    Ren, Jing; Huan, Yi; Ge, YaLi; Chang, YingJuan; Yin, Hong; Sun, LiJun; Wang, He

    2009-01-01

    The aim of this study was to evaluate the usefulness of diffusion-weighted imaging (DWI) in detecting seminal vesicle invasion (SVI). A total of 283 patients underwent conventional MRI and DWI before prostate cancer surgery. The apparent diffusion coefficient (ADC) values of all PCa foci, SVI and seminal vesicle were measured. T2 images alone and then T2 images combined with DWI were scored for the likelihood of SVI. The area under the receiver operating characteristic curve (AUC) was used to assess accuracy. Statistical significance was inferred at P<0.05. On pathological analysis, 39 patients had SVI. The ADC values of SVI were significantly lower than those of SV. The AUC for T2-weighted imaging plus DW imaging (0.897) was significantly larger (P<0.05) than that for T2-weighted imaging alone (0.779). T2 images combined with DWI shows significantly higher accuracy than T2-weighted imaging alone in the detection of SVI. (orig.)

  17. Importance of T2*-weighted gradient-echo MRI for diagnosis of cortical vein thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Fellner, Franz A. [Institut fuer Radiologie, Landes-Nervenklinik Wagner Jauregg, Linz (Austria) and Zentrales Radiologie Institut, Allgemeines Krankenhaus der Stadt Linz, Krankenhausstr. 9, 4020 Linz (Austria)]. E-mail: franz.fellner@akh.linz.at; Fellner, Claudia [Institut fuer Radiologie, Landes-Nervenklinik Wagner Jauregg, Linz (Austria); Aichner, Franz T. [Abteilung fuer Neurologie, Landes-Nervenklinik Wagner-Jauregg, Linz (Austria); Moelzer, Guenther [Institut fuer Radiologie, Landes-Nervenklinik Wagner Jauregg, Linz (Austria)

    2005-11-01

    We examined six patients with isolated venous thrombosis (n = 2), or venous thrombosis combined with sinus thrombosis (n = 4) (CVT). The clinical symptoms were non-specific (acute cephalea, paresis, epileptic seizure, progressive speech disorder). All examinations were performed on a 1.5 T system (Magnetom Symphony, Siemens, Erlangen, Germany), maximum gradient field strength 30 mT/m, minimal gradient rise time 450 {mu}s, according to the following protocol: Transverse T2-weighted turbo spin-echo (TSE), fluid attenuated inversion recovery (FLAIR), T1-weighted spin-echo (SE), before and after administration of contrast medium, T2*-weighted conventional gradient-echo (GRE), T2*-weighted spin-echo echo planar imaging (SE EPI), both without and with diffusion weighting as well as two-dimensional (2D) venous time-of-flight (TOF) MRA. The venous thromboses were best detectable in the T2*-weighted conventional GRE sequence in all patients. In two patients, the CVT was discernible only in this sequence. The sinus thrombosis was well discernible only in the T2*-weighted GRE sequence in only one case; in the remaining cases it was detectable only with difficulty. For these cases, other sequences such as SE, diffusion-weighted, or 2D-TOF-MRA sequence were superior. The T2*-weighted conventional GRE sequence was superior to the T2*-weighted SE EPI sequence in all patients. To sum up, it can be concluded, that T2*-weighted conventional GRE sequences are possibly the best method of detection of acute cortical vein thromboses. Therefore, it seems to be of benefit to integrate a T2*-weighted conventional GRE sequence into the MR-protocol for the diagnosis of isolated cortical vein thrombosis.

  18. Importance of T2*-weighted gradient-echo MRI for diagnosis of cortical vein thrombosis

    International Nuclear Information System (INIS)

    Fellner, Franz A.; Fellner, Claudia; Aichner, Franz T.; Moelzer, Guenther

    2005-01-01

    We examined six patients with isolated venous thrombosis (n = 2), or venous thrombosis combined with sinus thrombosis (n = 4) (CVT). The clinical symptoms were non-specific (acute cephalea, paresis, epileptic seizure, progressive speech disorder). All examinations were performed on a 1.5 T system (Magnetom Symphony, Siemens, Erlangen, Germany), maximum gradient field strength 30 mT/m, minimal gradient rise time 450 μs, according to the following protocol: Transverse T2-weighted turbo spin-echo (TSE), fluid attenuated inversion recovery (FLAIR), T1-weighted spin-echo (SE), before and after administration of contrast medium, T2*-weighted conventional gradient-echo (GRE), T2*-weighted spin-echo echo planar imaging (SE EPI), both without and with diffusion weighting as well as two-dimensional (2D) venous time-of-flight (TOF) MRA. The venous thromboses were best detectable in the T2*-weighted conventional GRE sequence in all patients. In two patients, the CVT was discernible only in this sequence. The sinus thrombosis was well discernible only in the T2*-weighted GRE sequence in only one case; in the remaining cases it was detectable only with difficulty. For these cases, other sequences such as SE, diffusion-weighted, or 2D-TOF-MRA sequence were superior. The T2*-weighted conventional GRE sequence was superior to the T2*-weighted SE EPI sequence in all patients. To sum up, it can be concluded, that T2*-weighted conventional GRE sequences are possibly the best method of detection of acute cortical vein thromboses. Therefore, it seems to be of benefit to integrate a T2*-weighted conventional GRE sequence into the MR-protocol for the diagnosis of isolated cortical vein thrombosis

  19. Automated image quality evaluation of T2 -weighted liver MRI utilizing deep learning architecture.

    Science.gov (United States)

    Esses, Steven J; Lu, Xiaoguang; Zhao, Tiejun; Shanbhogue, Krishna; Dane, Bari; Bruno, Mary; Chandarana, Hersh

    2018-03-01

    To develop and test a deep learning approach named Convolutional Neural Network (CNN) for automated screening of T 2 -weighted (T 2 WI) liver acquisitions for nondiagnostic images, and compare this automated approach to evaluation by two radiologists. We evaluated 522 liver magnetic resonance imaging (MRI) exams performed at 1.5T and 3T at our institution between November 2014 and May 2016 for CNN training and validation. The CNN consisted of an input layer, convolutional layer, fully connected layer, and output layer. 351 T 2 WI were anonymized for training. Each case was annotated with a label of being diagnostic or nondiagnostic for detecting lesions and assessing liver morphology. Another independently collected 171 cases were sequestered for a blind test. These 171 T 2 WI were assessed independently by two radiologists and annotated as being diagnostic or nondiagnostic. These 171 T 2 WI were presented to the CNN algorithm and image quality (IQ) output of the algorithm was compared to that of two radiologists. There was concordance in IQ label between Reader 1 and CNN in 79% of cases and between Reader 2 and CNN in 73%. The sensitivity and the specificity of the CNN algorithm in identifying nondiagnostic IQ was 67% and 81% with respect to Reader 1 and 47% and 80% with respect to Reader 2. The negative predictive value of the algorithm for identifying nondiagnostic IQ was 94% and 86% (relative to Readers 1 and 2). We demonstrate a CNN algorithm that yields a high negative predictive value when screening for nondiagnostic T 2 WI of the liver. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:723-728. © 2017 International Society for Magnetic Resonance in Medicine.

  20. Utility of re-windowing for MR T2-weighted images in differentiating between benign tumors and cysts

    International Nuclear Information System (INIS)

    Yamamoto, A.; Nishikawa, K.; Otonari-Yamamoto, M.; Sano, T.

    2009-01-01

    Both benign tumors and cysts in the oral and maxillofacial region show clear borders and homogeneously high signal intensity on magnetic resonance (MR T2-weighted images, making differentiation difficult without contrast enhancement. Windowing for brightness and contrast adjustment may be helpful in interpreting relative signal intensities on MR images. This study was performed to determine whether re-windowing against targeted lesions on T2-weighted images was a useful procedure that would enhance differentiation without invasive contrast enhancement. Twenty-six lesions (13 benign tumors, 13 cysts) that showed clear borders and homogeneously high signal intensity on T2-weighted images were examined. The windowing parameters of axial images were readjusted to emphasize contrast only inside the lesions using automatic density adjustment. Re-windowed images were reviewed by three experienced oral radiologists and categorized based on the internal homogeneity of the lesion into four grades: 0, heterogeneous; 1, slightly heterogeneous; 2, slightly homogeneous; 3, homogeneous. Re-windowing was then evaluated for its usefulness in differentiating between benign tumors and cysts. For cysts, the rates of homogeneous (grades 3 and 2) and heterogeneous intensity (grades 1 and 0) were 66.7 (26/39) and 33.3% (13/39), respectively. For benign tumors, these rates were 33.3 (13/39) and 66.7% (26/39), respectively. Cysts showed a higher rate of homogeneous intensity, while the opposite was true for benign tumors. A significant difference in distribution was observed between cysts and benign tumors (P 2 test). Re-windowing for T2-weighted images is helpful in differentiating between benign tumors and cysts with clear borders and homogeneously high signal intensity on T2-weighted images. (author)

  1. Intensity ratio curve analysis of small renal masses on T2-weighted magnetic resonance imaging: Differentiation of fat-poor angiomyolipoma from renal cell carcinoma.

    Science.gov (United States)

    Moriyama, Shingo; Yoshida, Soichiro; Tanaka, Hajime; Tanaka, Hiroshi; Yokoyama, Minato; Ishioka, Junichiro; Matsuoka, Yoh; Saito, Kazutaka; Kihara, Kazunori; Fujii, Yasuhisa

    2018-03-25

    To assess the diagnostic ability of a pixel intensity-based analysis in evaluating the magnetic resonance imaging characteristics of small renal masses, especially in differentiating fat-poor angiomyolipoma from renal cell carcinoma. T2-weighted images from 121 solid small renal masses (ratio curve was plotted using intensity ratios, which were ratios of signal intensities of tumor pixels (each pixel along a linear region of interest drawn across the renal tumor on T2-weighted image) to the signal intensity of a normal renal cortex. The diagnostic ability of the intensity ratio curve analysis was evaluated. The tumors were classified into three types: intensity ratio fat-poor angiomyolipoma (n = 19) with no pseudocapsule, iso-low intensity and no heterogeneity; intensity ratio clear cell renal cell carcinoma (n = 76) with a pseudocapsule, iso-high intensity and heterogeneity; and other type of intensity ratio (n = 26), including tumors that did not fall into the above two categories. The sensitivity/specificity/accuracy of the intensity ratio curve analysis in diagnosing fat-poor angiomyolipoma was 93%/94%/94%, respectively. When the intensity ratio curve analysis was applied only to the tumor with undetermined radiological diagnosis, the sensitivity for diagnosing fat-poor angiomyolipoma compared with subjective reading alone significantly improved (93% vs 50%; P = 0.014). Our novel semiquantitative model for combined assessment of key features of fat-poor angiomyolipoma, including low intensity, homogeneity and absence of a pseudocapsule on T2-weighted image, might make diagnosis of fat-poor angiomyolipoma more accurate. © 2018 The Japanese Urological Association.

  2. Spot Sign in Acute Intracerebral Hemorrhage in Dynamic T1-Weighted Magnetic Resonance Imaging.

    Science.gov (United States)

    Schindlbeck, Katharina A; Santaella, Anna; Galinovic, Ivana; Krause, Thomas; Rocco, Andrea; Nolte, Christian H; Villringer, Kersten; Fiebach, Jochen B

    2016-02-01

    In computed tomographic imaging of acute intracerebral hemorrhage spot sign on computed tomographic angiography has been established as a marker for hematoma expansion and poor clinical outcome. Although, magnetic resonance imaging (MRI) can accurately visualize acute intracerebral hemorrhage, a corresponding MRI marker is lacking to date. We prospectively examined 50 consecutive patients with acute intracerebral hemorrhage within 24 hours of symptom onset. The MRI protocol consisted of a standard stroke protocol and dynamic contrast-enhanced T1-weighted imaging with a time resolution of 7.07 s/batch. Stroke scores were assessed at admission and at time of discharge. Volume measurements of hematoma size and spot sign were performed with MRIcron. Contrast extravasation within sites of the hemorrhage (MRI spot sign) was seen in 46% of the patients. Patients with an MRI spot sign had a significantly shorter time to imaging than those without (Pspot sign compared with those without (P≤0.001). Hematoma expansion was observed in the spot sign group compared with the nonspot sign group, although the differences were not significant. Spot sign can be detected using MRI on postcontrast T1-weighted and dynamic T1-weighted images. It is associated with worse clinical outcome. The time course of contrast extravasation in dynamic T1 images indicates that these spots represent ongoing bleeding. © 2015 American Heart Association, Inc.

  3. Optimizing T2-weighted magnetic resonance sequences for surface coil microimaging of the eye with regard to lid, eyeball and head moving artifacts.

    Science.gov (United States)

    Obata, Takayuki; Uemura, Koji; Nonaka, Hiroi; Tamura, Mitsuru; Tanada, Shuji; Ikehira, Hiroo

    2006-01-01

    To acquire high-resolution magnetic resonance (MR) images, we developed a new blinking artifact reduced pulse (BARP) sequence with a surface coil specialized for microscopic imaging (47 mm in diameter). To reduce eye movement, we ascertained that the subjects' eyes were kept open and fixated to the target in the 1.5-T MR gantry. To reduce motion artifacts from blinking, we inserted rest periods for blinking (1.5 s within every 5 s) during MR scanning (T2-weighted fast spin echo; repetition time, 5 s; echo time, 100 ms; echo train, 11; matrix, 256 x 128; field of view, 5 cm; 1-mm thickness x 30 slices). Three scans (100 s x 3) were performed for each normal subject, and they were added together after automatic adjustment for location to reduce quality loss caused by head motion. T2-weighted MR images were acquired with a high resolution and a high signal-to-noise ratio. Motion artifacts were reduced with BARP, as compared with those with random blinking. Intraocular structures such as the iris and ciliary muscles were clearly visualized. Because the whole eye can be covered with a 1-mm thickness by this method, three-dimensional maps can easily be generated from the obtained images. The application of BARP with a surface coil of the human eye might become a useful and widely adopted procedure for MR microimaging.

  4. SU-F-I-16: Short Breast MRI with High-Resolution T2-Weighted and Dynamic Contrast Enhanced T1-Weighted Images

    International Nuclear Information System (INIS)

    Ma, J; Son, J; Arun, B; Hazle, J; Hwang, K; Madewell, J; Yang, W; Dogan, B; Wang, K; Bayram, E

    2016-01-01

    Purpose: To develop and demonstrate a short breast (sb) MRI protocol that acquires both T2-weighted and dynamic contrast-enhanced T1-weighted images in approximately ten minutes. Methods: The sb-MRI protocol consists of two novel pulse sequences. The first is a flexible fast spin-echo triple-echo Dixon (FTED) sequence for high-resolution fat-suppressed T2-weighted imaging, and the second is a 3D fast dual-echo spoiled gradient sequence (FLEX) for volumetric fat-suppressed T1-weighted imaging before and post contrast agent injection. The flexible FTED sequence replaces each single readout during every echo-spacing period of FSE with three fast-switching bipolar readouts to produce three raw images in a single acquisition. These three raw images are then post-processed using a Dixon algorithm to generate separate water-only and fat-only images. The FLEX sequence acquires two echoes using dual-echo readout after each RF excitation and the corresponding images are post-processed using a similar Dixon algorithm to yield water-only and fat-only images. The sb-MRI protocol was implemented on a 3T MRI scanner and used for patients who had undergone concurrent clinical MRI for breast cancer screening. Results: With the same scan parameters (eg, spatial coverage, field of view, spatial and temporal resolution) as the clinical protocol, the total scan-time of the sb-MRI protocol (including the localizer, bilateral T2-weighted, and dynamic contrast-enhanced T1-weighted images) was 11 minutes. In comparison, the clinical breast MRI protocol took 43 minutes. Uniform fat suppression and high image quality were consistently achieved by sb-MRI. Conclusion: We demonstrated a sb-MRI protocol comprising both T2-weighted and dynamic contrast-enhanced T1-weighted images can be performed in approximately ten minutes. The spatial and temporal resolution of the images easily satisfies the current breast MRI accreditation guidelines by the American College of Radiology. The protocol has the

  5. SU-F-I-16: Short Breast MRI with High-Resolution T2-Weighted and Dynamic Contrast Enhanced T1-Weighted Images

    Energy Technology Data Exchange (ETDEWEB)

    Ma, J; Son, J; Arun, B; Hazle, J; Hwang, K; Madewell, J; Yang, W; Dogan, B [UT MD Anderson Cancer Center, Houston, TX (United States); Wang, K; Bayram, E [GE Healthcare Technologies, Waukesha, Wisconsin (United States)

    2016-06-15

    Purpose: To develop and demonstrate a short breast (sb) MRI protocol that acquires both T2-weighted and dynamic contrast-enhanced T1-weighted images in approximately ten minutes. Methods: The sb-MRI protocol consists of two novel pulse sequences. The first is a flexible fast spin-echo triple-echo Dixon (FTED) sequence for high-resolution fat-suppressed T2-weighted imaging, and the second is a 3D fast dual-echo spoiled gradient sequence (FLEX) for volumetric fat-suppressed T1-weighted imaging before and post contrast agent injection. The flexible FTED sequence replaces each single readout during every echo-spacing period of FSE with three fast-switching bipolar readouts to produce three raw images in a single acquisition. These three raw images are then post-processed using a Dixon algorithm to generate separate water-only and fat-only images. The FLEX sequence acquires two echoes using dual-echo readout after each RF excitation and the corresponding images are post-processed using a similar Dixon algorithm to yield water-only and fat-only images. The sb-MRI protocol was implemented on a 3T MRI scanner and used for patients who had undergone concurrent clinical MRI for breast cancer screening. Results: With the same scan parameters (eg, spatial coverage, field of view, spatial and temporal resolution) as the clinical protocol, the total scan-time of the sb-MRI protocol (including the localizer, bilateral T2-weighted, and dynamic contrast-enhanced T1-weighted images) was 11 minutes. In comparison, the clinical breast MRI protocol took 43 minutes. Uniform fat suppression and high image quality were consistently achieved by sb-MRI. Conclusion: We demonstrated a sb-MRI protocol comprising both T2-weighted and dynamic contrast-enhanced T1-weighted images can be performed in approximately ten minutes. The spatial and temporal resolution of the images easily satisfies the current breast MRI accreditation guidelines by the American College of Radiology. The protocol has the

  6. Measurement of brain oxygenation changes using dynamic T1-weighted imaging

    DEFF Research Database (Denmark)

    Haddock, Bryan; Larsson, Henrik B W; Hansen, Adam E

    2013-01-01

    Magnetic resonance imaging (MRI) has proven useful in evaluating oxygenation in several types of tissue and blood. This study evaluates brain tissue oxygenation changes between normoxia and hyperoxia in healthy subjects using dynamic T1 and T2*-weighted imaging sequences. The change in FiO2 induced...... by hyperoxia caused a significant decrease in T1. A model to determine changes in tissue oxygen tension from the T1-weighted MRI signal is presented based on previous findings that T1 is sensitive to oxygen tension whereas T2* is sensitive to blood saturation. The two sequences produce results with different...... regional and temporal dynamics. These differences combined with results from simulations of the T1 signal intensities, indicate an increase in extravascular oxygen tension during hyperoxia. This study concludes that T1 and T2* responses to FiO2 serve as independent biomarkers of oxygen physiology...

  7. Comparison of [11C]choline Positron Emission Tomography With T2- and Diffusion-Weighted Magnetic Resonance Imaging for Delineating Malignant Intraprostatic Lesions

    International Nuclear Information System (INIS)

    Chang, Joe H.; Lim Joon, Daryl; Davis, Ian D.; Lee, Sze Ting; Hiew, Chee-Yan; Esler, Stephen; Gong, Sylvia J.; Wada, Morikatsu; Clouston, David; O'Sullivan, Richard; Goh, Yin P.; Bolton, Damien; Scott, Andrew M.; Khoo, Vincent

    2015-01-01

    Purpose: The purpose of this study was to compare the accuracy of [ 11 C]choline positron emission tomography (CHOL-PET) with that of the combination of T2-weighted and diffusion-weighted (T2W/DW) magnetic resonance imaging (MRI) for delineating malignant intraprostatic lesions (IPLs) for guiding focal therapies and to investigate factors predicting the accuracy of CHOL-PET. Methods and Materials: This study included 21 patients who underwent CHOL-PET and T2W/DW MRI prior to radical prostatectomy. Two observers manually delineated IPL contours for each scan, and automatic IPL contours were generated on CHOL-PET based on varying proportions of the maximum standardized uptake value (SUV). IPLs identified on prostatectomy specimens defined reference standard contours. The imaging-based contours were compared with the reference standard contours using Dice similarity coefficient (DSC), and sensitivity and specificity values. Factors that could potentially predict the DSC of the best contouring method were analyzed using linear models. Results: The best automatic contouring method, 60% of the maximum SUV (SUV 60 ) , had similar correlations (DSC: 0.59) with the manual PET contours (DSC: 0.52, P=.127) and significantly better correlations than the manual MRI contours (DSC: 0.37, P<.001). The sensitivity and specificity values were 72% and 71% for SUV 60 ; 53% and 86% for PET manual contouring; and 28% and 92% for MRI manual contouring. The tumor volume and transition zone pattern could independently predict the accuracy of CHOL-PET. Conclusions: CHOL-PET is superior to the combination of T2W/DW MRI for delineating IPLs. The accuracy of CHOL-PET is insufficient for gland-sparing focal therapies but may be accurate enough for focal boost therapies. The transition zone pattern is a new classification that may predict how well CHOL-PET delineates IPLs

  8. Assessment of the image quality and tumor detectability of breath-hold T2-weighted imaging of liver tumors using a fast gradient MR system

    International Nuclear Information System (INIS)

    Yoshida, Kotaro; Suto, Yuji; Sugihara, Shuji; Tokuda, Yukiko

    1996-01-01

    Fourteen patients with various types of focal liver tumors were imaged with turbo spin-echo (TSE), breath-hold TSE (BH-TSE) and half-Fourier single-shot TSE (HASTE) pulse sequences using a fast gradient magnetic resonance imaging (MRI) system. We compared the T2-weighted images of the liver with the TSE, BH-TSE, HASTE and conventional spin-echo (SE) pulse sequences in order to determine whether those fast T2-weighted images, including fat suppressed images, could replace SE images. In quantitative and qualitative analysis, the fast T2-weighted images were slightly superior to the SE images, but they were inferior in the conspicuousness of liver tumor to the SE images. These findings suggest that the fast T2-weighted images can shorten the examination time of the liver MRI, but cannot replace the T2-weighted SE images because of the low conspicuousness. (author)

  9. High resolution T{sub 2}{sup *}-weighted magnetic resonance imaging at 3 Tesla using PROPELLER-EPI

    Energy Technology Data Exchange (ETDEWEB)

    Kraemer, Martin; Reichenbach, Juergen R. [Jena University Hospital (Germany). Medical Physics Group

    2014-09-01

    We report the application of PROPELLER-EPI for high resolution T{sub 2}{sup *}-weighted imaging with sub-millimeter in-plane resolution on a clinical 3 Tesla scanner. Periodically rotated blades of a long-axis PROPELLER-EPI sequence were acquired with fast gradient echo readout and acquisition matrix of 320 x 50 per blade. Images were reconstructed by using 2D-gridding, phase and geometric distortion correction and compensation of resonance frequency drifts that occurred during extended measurements. To characterize these resonance frequency offsets, short FID calibration measurements were added to the PROPELLER-EPI sequence. Functional PROPELLER-EPI was performed with volunteers using a simple block design of right handed finger tapping. Results indicate that PROPELLER-EPI can be employed for fast, high resolution T{sub 2}{sup *}-weighted imaging provided geometric distortions and possible resonance frequency drifts are properly corrected. Even small resonance frequency drifts below 10 Hz as well as non-corrected geometric distortions degraded image quality substantially. In the initial fMRI experiment image quality and signal-to-noise ratio was sufficient for obtaining high resolution functional activation maps. (orig.)

  10. Paradoxical signal pattern of mediastinal cysts on T2-weighted MR imaging: phantom and clinical study

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Ken, E-mail: k-ueda@radiol.med.osaka-u.ac.jp [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan); Yanagawa, Masahiro [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan); Ueguchi, Takashi [Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan); Satoh, Yukihisa; Kawai, Misa; Gyobu, Tomoko; Sumikawa, Hiromitsu; Honda, Osamu; Tomiyama, Noriyuki [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan)

    2014-06-15

    Purpose: To evaluate the intracystic MRI (magnetic resonance imaging) signal intensity of mediastinal cystic masses on T2-weighted images. Materials and methods: A phantom study was performed to evaluate the signal intensity of a mediastinal cystic mass phantom (rubber balloon containing water) adjacent to a cardiac phantom pulsing at the rate of 60/min. T2-weighted images (sequence, fast spin echo [FSE] and single shot fast spin echo [SSFSE]) were acquired for the mediastinal cystic mass phantom. Further, a clinical study was performed in 33 patients (16 men, 17 women; age range, 19-85 years; mean, 65years) with thymic cysts or pericardial cysts. In all patients, T2-weighted images (FSE and SSFSE) were acquired. The signal intensity of cystic lesion was evaluated and was compared with that of muscle. A region of interest (ROI) was positioned on the standard MR console, and signal intensity of the cystic mass (cSI), that of the muscle (mSI), and the rate of absolute value of cSI–mSI to standard deviation (SD) of background noise (|cSI–mSI|/SD = CNR [contrast-to-noise ratio]) were measured. Results: The phantom study demonstrated that the rate phantom-ROI/saline-ROI was higher in SSFSE (0.36) than in FSE (0.19). In clinical cases, the degree of the signal intensity was higher in SSFSE than in FSE. The CNR was significantly higher in SSFSE (mean ± standard deviation, 111.0 ± 47.6) than in FSE (72.8 ± 36.6) (p < 0.001, Wilcoxon signed-rank test). Conclusions: Anterior mediastinal cysts often show lower signal intensity than the original signal intensity of water on T2-weighted images. SSFSE sequence reduces this paradoxical signal pattern on T2-weighted images, which may otherwise cause misinterpretation when assessing cystic lesions.

  11. Paradoxical signal pattern of mediastinal cysts on T2-weighted MR imaging: phantom and clinical study

    International Nuclear Information System (INIS)

    Ueda, Ken; Yanagawa, Masahiro; Ueguchi, Takashi; Satoh, Yukihisa; Kawai, Misa; Gyobu, Tomoko; Sumikawa, Hiromitsu; Honda, Osamu; Tomiyama, Noriyuki

    2014-01-01

    Purpose: To evaluate the intracystic MRI (magnetic resonance imaging) signal intensity of mediastinal cystic masses on T2-weighted images. Materials and methods: A phantom study was performed to evaluate the signal intensity of a mediastinal cystic mass phantom (rubber balloon containing water) adjacent to a cardiac phantom pulsing at the rate of 60/min. T2-weighted images (sequence, fast spin echo [FSE] and single shot fast spin echo [SSFSE]) were acquired for the mediastinal cystic mass phantom. Further, a clinical study was performed in 33 patients (16 men, 17 women; age range, 19-85 years; mean, 65years) with thymic cysts or pericardial cysts. In all patients, T2-weighted images (FSE and SSFSE) were acquired. The signal intensity of cystic lesion was evaluated and was compared with that of muscle. A region of interest (ROI) was positioned on the standard MR console, and signal intensity of the cystic mass (cSI), that of the muscle (mSI), and the rate of absolute value of cSI–mSI to standard deviation (SD) of background noise (|cSI–mSI|/SD = CNR [contrast-to-noise ratio]) were measured. Results: The phantom study demonstrated that the rate phantom-ROI/saline-ROI was higher in SSFSE (0.36) than in FSE (0.19). In clinical cases, the degree of the signal intensity was higher in SSFSE than in FSE. The CNR was significantly higher in SSFSE (mean ± standard deviation, 111.0 ± 47.6) than in FSE (72.8 ± 36.6) (p < 0.001, Wilcoxon signed-rank test). Conclusions: Anterior mediastinal cysts often show lower signal intensity than the original signal intensity of water on T2-weighted images. SSFSE sequence reduces this paradoxical signal pattern on T2-weighted images, which may otherwise cause misinterpretation when assessing cystic lesions

  12. 7T T-2*-weighted magnetic resonance imaging reveals cortical phase differences between early- and late-onset Alzheimer's disease

    NARCIS (Netherlands)

    van Rooden, S.; Doan, N.T.; Versluis, M.J.; Goos, J.D.C.; Webb, A.G.; Oleksik, A.M.; van der Flier, W.M.; Scheltens, P.; Barkhof, F.; Weverlinge-Rynsburger, A.W.E.; Blauw, G. J.; Reiber, J.H.C.; van Buchem, M.A.; Milles, J.; van der Grond, J.

    2015-01-01

    The aim of this study is to explore regional iron-related differences in the cerebral cortex, indicative of Alzheimer's disease pathology, between early- and late-onset Alzheimer's disease (EOAD, LOAD, respectively) patients using 7T magnetic resonance phase images. High-resolution T

  13. Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Inst. de Radiologia]. E-mail: mvmfonte@uol.com.br; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Radiologia; Reed, Umbertina Conti [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Neurologia; Rosemberg, Sergio [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Dept. de Patologia

    2008-11-15

    To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

  14. Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes; Reed, Umbertina Conti; Rosemberg, Sergio

    2008-01-01

    To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

  15. Fusion of High b-valve diffusion-weighted and T2-weighted MR images improves identification of lymph nodes in the pelvis

    International Nuclear Information System (INIS)

    Mir, N.; Sohaib, S.A.; Collins, D.; Koh, D.M.

    2010-01-01

    Full text: Accurate identification of lymph nodes facilities nodal assessment by size, morphological or MR lymphographic criteria. We compared the MR detection of lymph nodes in patients with pelvic cancers using T2-weighted imaging, and fusion of diffusion-weighted imaging (OWl) and T2-weighted imaging. Twenty patients with pelvic tumours underwent 5-mm axial T2-weighted and OWl (b-values 0-750 s/mm 2 ) on a L 5T system. Fusion images of b = 750 s/mm 2 diffusion-weighted MR and T2-weighted images were created. Two radiologists evaluated in consensus the T2-weighted images and fusion images independently. For each image set, the location and diameter of pelvic nodes were recorded, and nodal visibility was scored using a 4-point scale (0-3). Nodal visualisation was compared using Relative to an Identified Distribution (RIDIT) analysis. The mean RIDIT score describes the probability that a randomly selected node will be better visualised relative to the other image set. One hundred fourteen pelvic nodes (mean 5.9 mm; 2-10 mm) were identified on T2-weighted images and 161 nodes (mean 4.3 mm; 2-10 mm) on fusion images. Using fusion images, 47 additional nodes were detected compared with T2-weighted images alone (eight external iliac, 24 inguinal, 12 obturator, two peri-rectal, one presacral). Nodes detected only on fusion images were 2-9 mm (mean 3.7 mm). Nodal visualisation was better using fusion images compared with T2-weighted images (mean RIDIT score 0.689 vs 0.302). Fusion of diffusion-weighted MR with T2-weighted images improves identification of pelvic lymph nodes compared with T2-weighted images alone. The improved nodal identification may aid treatment planning and further nodal characterisation.

  16. Follow-up of regional myocardial T2 relaxation times in patients with myocardial infarction evaluated with magnetic resonance imaging

    International Nuclear Information System (INIS)

    Krauss, X.H.; Wall, E. van der; Laarse, A. van der; Dijkman, P.R.M. van; Bruschke, A.V.G.; Doornbos, J.; Roos, A. de; Voorthuisen, A.E. van

    1990-01-01

    Multi-echo spin-echo cardiac magnetic resonance imaging studies (echo times 30, 60, 90 and 120 ms) were performed in 19 patients with a 7-14-day (mean 10) old myocardial infarction and were repeated in 13 patients 4-7 months (mean 6) later. Also, 10 normal subjects were studied with magnetic resonance imaging. T2 relaxation times of certain left ventricular segments were calculated from the signal intensities at echo times of 30 and 90 ms. Compared to normal individuals, the mean T2 values on the early magnetic resonance images of the patients with inferior infarction showed significantly prolonged T2 times in the inferiorly localized segments, while on the follow-up magnetic resonance images the T2 times had almost returned to the normal range. Also the patients with anterior infarction showed significantly prolonged T2 times in the anteriorly localized segments on the early nuclear magnetic resonance images, but the T2 times remained prolonged at the follow-up magnetic resonance images. For every patient a myocardial damage score was determined, which was defined as the sum of the segmental T2 values in the patients minus the upper limit of normal T2 values obtained from the normal volunteers (= mean normal+2SD). The damage score on both the early and late magnetic resonance imaging study correlated well with the infarction size determined by myocardial enzyme release. Only the patients with an inferior infarction showed a significant decrease in damage score at follow-up magnetic resonance imaging. It is concluded that the regional T2 relaxation times are increased in infarcted myocardial regions and may remain prolonged for at least up to 7 months after the acute event, particularly in patients with an anterior infarction. These findings demonstrate the clinical potential of T2-weighted magnetic resonance imaging studies for detecting myocardial infarction, and estimating infarct size for an extended period after acute myocardial infarction. (author). 29 refs

  17. Robust T1-weighted structural brain imaging and morphometry at 7T using MP2RAGE.

    Directory of Open Access Journals (Sweden)

    Kieran R O'Brien

    Full Text Available PURPOSE: To suppress the noise, by sacrificing some of the signal homogeneity for numerical stability, in uniform T1 weighted (T1w images obtained with the magnetization prepared 2 rapid gradient echoes sequence (MP2RAGE and to compare the clinical utility of these robust T1w images against the uniform T1w images. MATERIALS AND METHODS: 8 healthy subjects (29.0 ± 4.1 years; 6 Male, who provided written consent, underwent two scan sessions within a 24 hour period on a 7T head-only scanner. The uniform and robust T1w image volumes were calculated inline on the scanner. Two experienced radiologists qualitatively rated the images for: general image quality; 7T specific artefacts; and, local structure definition. Voxel-based and volume-based morphometry packages were used to compare the segmentation quality between the uniform and robust images. Statistical differences were evaluated by using a positive sided Wilcoxon rank test. RESULTS: The robust image suppresses background noise inside and outside the skull. The inhomogeneity introduced was ranked as mild. The robust image was significantly ranked higher than the uniform image for both observers (observer 1/2, p-value = 0.0006/0.0004. In particular, an improved delineation of the pituitary gland, cerebellar lobes was observed in the robust versus uniform T1w image. The reproducibility of the segmentation results between repeat scans improved (p-value = 0.0004 from an average volumetric difference across structures of ≈ 6.6% to ≈ 2.4% for the uniform image and robust T1w image respectively. CONCLUSIONS: The robust T1w image enables MP2RAGE to produce, clinically familiar T1w images, in addition to T1 maps, which can be readily used in uniform morphometry packages.

  18. Analysis of artefacts and detail resolution of lung MRI with breath-hold T1-weighted gradient-echo and T2-weighted fast spin-echo sequences with respiratory triggering

    International Nuclear Information System (INIS)

    Biederer, J.; Reuter, M.; Both, M.; Grimm, J.; Heller, M.; Muhle, C.; Graessner, J.

    2002-01-01

    The aim of this study was to evaluate feasibility and limitations of two MR sequences for imaging of the lung using a semi-quantitative rating scale. Ten healthy volunteers were assessed with a breath-hold T1-weighted gradient-recalled-echo (TR/TE=129/2.2 ms, matrix 173 x 256) and a T2-weighted turbo spin-echo (TSE) sequence with respiratory triggering (TR/TE=3000-5000/120 ms, matrix 270 x 512) in axial 6-mm slices. The T1-weighted GRE protocol included a pre-saturation pulse over the mediastinal structures. Artefacts and resolution of vessel/airway structures in each lung segment were evaluated by two observers (10 volunteers, 180 segments). Cardiac and vessel pulsation artefacts predominated on T1-weighted GRE, respiration artefacts on T2-weighted TSE (lingula and middle lobe). Pre-saturation of the mediastinum reduced pulsation artefacts on T1-weighted GRE. T1-weighted GRE images were improved by bright flow signal of vessels, whereas image quality of T2-weighted TSE was reduced by black-blood effects in central parts of the lung. Delineation of lung periphery and the mediastinum was superior with T2-weighted TSE. Segmental/sub-segmental vessels (up to fourth/fifth order) and bronchi (up to third order) were identified. All 180 lung segments were imaged in diagnostic quality with at least one of the two sequences (T1-weighted GRE not diagnostic in 9 of 180, T2-weighted TSE in 4 of 180). Both sequences were found to be complementary: superior identification of gross lung anatomy with T1-weighted GRE and higher detail resolution in the periphery and the mediastinum with T2-weighted TSE. (orig.)

  19. Introduction of High Throughput Magnetic Resonance T2-Weighted Image Texture Analysis for WHO Grade 2 and 3 Gliomas.

    Science.gov (United States)

    Kinoshita, Manabu; Sakai, Mio; Arita, Hideyuki; Shofuda, Tomoko; Chiba, Yasuyoshi; Kagawa, Naoki; Watanabe, Yoshiyuki; Hashimoto, Naoya; Fujimoto, Yasunori; Yoshimine, Toshiki; Nakanishi, Katsuyuki; Kanemura, Yonehiro

    2016-01-01

    Reports have suggested that tumor textures presented on T2-weighted images correlate with the genetic status of glioma. Therefore, development of an image analyzing framework that is capable of objective and high throughput image texture analysis for large scale image data collection is needed. The current study aimed to address the development of such a framework by introducing two novel parameters for image textures on T2-weighted images, i.e., Shannon entropy and Prewitt filtering. Twenty-two WHO grade 2 and 28 grade 3 glioma patients were collected whose pre-surgical MRI and IDH1 mutation status were available. Heterogeneous lesions showed statistically higher Shannon entropy than homogenous lesions (p = 0.006) and ROC curve analysis proved that Shannon entropy on T2WI was a reliable indicator for discrimination of homogenous and heterogeneous lesions (p = 0.015, AUC = 0.73). Lesions with well-defined borders exhibited statistically higher Edge mean and Edge median values using Prewitt filtering than those with vague lesion borders (p = 0.0003 and p = 0.0005 respectively). ROC curve analysis also proved that both Edge mean and median values were promising indicators for discrimination of lesions with vague and well defined borders and both Edge mean and median values performed in a comparable manner (p = 0.0002, AUC = 0.81 and p image metrics that reflect lesion texture described on T2WI. These two metrics were validated by readings of a neuro-radiologist who was blinded to the results. This observation will facilitate further use of this technique in future large scale image analysis of glioma.

  20. Quantitative and qualitative evaluation of brain diffusion weighted magnetic resonance imaging comparison with 1.5 T and 3.0 T units

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Eun Hoe [Dept. of Radiological Science, Cheongju University, Cheongju (Korea, Republic of); Dong, Kyung Rae [Dept. of Radiological Technology, Gwangju Health University, Gwangju (Korea, Republic of)

    2017-02-15

    DWI of biological effects are independent of magnetic field strength in various regions. High field strength, however, does affect the signal to noise ratio (SNR) and artifacts of diffusion weighted imaging (DWI) images, which ultimately will influence the quantitative of diffusion imaging . In this study, the effects of field strength on DWI are reviewed. The effects of the diseases also are discussed. Comparing DWI in cerebellum, WM, GM, Hyperacute region measurements both as a function of field strength (1.5 T and 3.0 T). Overall, the SNR of the DWI roughly doubled going from 1.5 T to 3.0 T. In summary, DWI studies at 3.0 T is provided significantly improved DWI measurements relative to studies at 1.5 T.

  1. The reliability of identifying the Omega sign using axial T2-weighted magnetic resonance imaging.

    Science.gov (United States)

    Zakaria, Hesham Mostafa; Massa, Peter Joseph; Smith, Richard L; Moharram, Tarek Hazem; Corrigan, John; Lee, Ian; Schultz, Lonni; Hu, Jianhui; Patel, Suresh; Griffith, Brent

    2018-01-01

    Preoperative identification of the eloquent brain is important for neurosurgical planning. One common method of finding the motor cortex is by localizing "the Omega sign." No studies have tested the reliability of imaging to identify the Omega sign. We identified 40 recent and consecutive patients who had undergone preoperative functional magnetic resonance imaging for identification of the hand motor area prior to tumor resection. We recruited 11 neurosurgical residents of various levels of training and one board-certified neurosurgeon to identify the hand motor cortex Omega. Testees were given axial images of T2-weighted MRI and placed marks where they expected to find the Omega. Two board-certified radiologists graded and quantified the localization attempts. Inter-rater reliability was assessed using the kappa statistic, and Rao-Scott chi-square tests were used to examine the relationship between clinical factors and testees' experience with correct identification of the Omega sign. The overall correct identification rate was 69.9% (95% CI = 63.4-75.7), ranging from 36.6% to 92.7% among all raters for the tumor side and from 46.2% to 97.4% for the non-tumor side. Anatomic distortion greatly affected correct identification ( p Omega than junior residents ( p Omega sign is poor, with a Fleiss kappa of 0.23. We concluded that correct identification of the Omega sign is affected by tumor distortion and experience but overall is not reliable. This underscores the limitations of anatomic landmarks and the importance of utilizing multiple scanning planes and preoperative fMRI for appropriate localization.

  2. Comparison of different magnetic resonance cholangiography techniques in living liver donors including Gd-EOB-DTPA enhanced T1-weighted sequences.

    Directory of Open Access Journals (Sweden)

    Sonja Kinner

    Full Text Available Preoperative evaluation of potential living liver donors (PLLDs includes the assessment of the biliary anatomy to avoid postoperative complications. Aim of this study was to compare T2-weighted (T2w and Gd-EOB-DTPA enhanced T1-weighted (T1w magnetic resonance cholangiography (MRC techniques in the evaluation of PLLDs.30 PLLDs underwent MRC on a 1.5 T Magnetom Avanto (Siemens, Erlangen, Germany using (A 2D T2w HASTE (Half Fourier Acquisition Single Shot Turbo Spin Echo fat saturated (fs in axial plane, (B 2D T2w HASTE fs thick slices in coronal plane, (C free breathing 3D T2w TSE (turbo spin echo RESTORE (high-resolution navigator corrected plus (D maximum intensity projections (MIPs, (E T2w SPACE (sampling perfection with application optimized contrasts using different flip angle evolutions plus (F MIPs and (G T2w TSE BLADE as well as Gd-EOB-DTPA T1w images without (G and with (H inversion recovery. Contrast enhanced CT cholangiography served as reference imaging modality. Two independent reviewers evaluated the biliary tract anatomy on a 5-point scale subjectively and objectively. Data sets were compared using a Mann-Whitney-U-test. Kappa values were also calculated.Source images and maximum intensity projections of 3D T2w TSE sequences (RESTORE and SPACE proved to be best for subjective and objective evaluation directly followed by 2D HASTE sequences. Interobserver variabilities were good to excellent (k = 0.622-0.804.3D T2w sequences are essential for preoperative biliary tract evaluation in potential living liver donors. Furthermore, our results underline the value of different MRCP sequence types for the evaluation of the biliary anatomy in PLLDs including Gd-EOB-DTPA enhanced T1w MRC.

  3. Introduction of High Throughput Magnetic Resonance T2-Weighted Image Texture Analysis for WHO Grade 2 and 3 Gliomas.

    Directory of Open Access Journals (Sweden)

    Manabu Kinoshita

    Full Text Available Reports have suggested that tumor textures presented on T2-weighted images correlate with the genetic status of glioma. Therefore, development of an image analyzing framework that is capable of objective and high throughput image texture analysis for large scale image data collection is needed. The current study aimed to address the development of such a framework by introducing two novel parameters for image textures on T2-weighted images, i.e., Shannon entropy and Prewitt filtering. Twenty-two WHO grade 2 and 28 grade 3 glioma patients were collected whose pre-surgical MRI and IDH1 mutation status were available. Heterogeneous lesions showed statistically higher Shannon entropy than homogenous lesions (p = 0.006 and ROC curve analysis proved that Shannon entropy on T2WI was a reliable indicator for discrimination of homogenous and heterogeneous lesions (p = 0.015, AUC = 0.73. Lesions with well-defined borders exhibited statistically higher Edge mean and Edge median values using Prewitt filtering than those with vague lesion borders (p = 0.0003 and p = 0.0005 respectively. ROC curve analysis also proved that both Edge mean and median values were promising indicators for discrimination of lesions with vague and well defined borders and both Edge mean and median values performed in a comparable manner (p = 0.0002, AUC = 0.81 and p < 0.0001, AUC = 0.83, respectively. Finally, IDH1 wild type gliomas showed statistically lower Shannon entropy on T2WI than IDH1 mutated gliomas (p = 0.007 but no difference was observed between IDH1 wild type and mutated gliomas in Edge median values using Prewitt filtering. The current study introduced two image metrics that reflect lesion texture described on T2WI. These two metrics were validated by readings of a neuro-radiologist who was blinded to the results. This observation will facilitate further use of this technique in future large scale image analysis of glioma.

  4. T2[sup *] weighted MR imaging for the diagnosis of the perforation of triangular fibrocartilage; Comparison with arthrography

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Taro; Nakamura, Eiziro; Ahsoh, Kuniichi; Masumi, Shogo (Oita Medical Univ., Takatsuki (Japan))

    1994-05-01

    Perforation of the triangular fibrocartilage (TFC) has been considered an important factor in the etiology of pain in the ulnar wrist joint, and arthrography has been used conventionally to diagnose the perforation. Recently, magnetic resonance imaging (MRI) has been used to diagnose TFC perforation. Gundy et al. examined cadaver wrists with Tl weighted imaging and arthrography, and obtained findings suggesting that arthrography provides a more accurate diagnosis of the TFC perforation. To our knowledge, no comparison has yet been made between T2[sup *] weighted imaging and arthrography in the diagnosis of TFC perforation. The present study compared the usefulness of T2[sup *]-weighted imaging and arthrography in the diagnosis of TFC perforation in 22 wrist joints of 11 cadavers (5 males and 6 females with ages ranging from 61 to 92 years and an average age of 78.8 years) fixed in 60% formalin. The specimens were firstly analyzed by a T2[sup *]-weighted 0.5T MRI scan and subsequently by arthrography. After diagnosing the image obtained by the two methods, the accuracy of the diagnosis was determined by comparison with the macroscopic findings of autopsy, including the presence and degree of TFC perforation. A T2[sup *]-weighted MRI scan of the TFC perforation showed high-intensity areas over the distal radio-ulnar joint, and demonstrated the same diagnostic accuracy as arthrography, providing correct diagnoses in all cases other than linear perforation. However, neither of the image diagnostic methods allowed definition of the type of perforation. (author).

  5. MRI of the anterior talofibular ligament, talar cartilage and os subfibulare: Comparison of isotropic resolution 3D and conventional 2D T2-weighted fast spin-echo sequences at 3.0 T

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Jisook; Cha, Jang Gyu [Soonchunhyang University Bucheon Hospital, Department of Radiology, Wonmi-gu, Bucheon-si (Korea, Republic of); Lee, Young Koo [Soonchunhyang University Bucheon Hospital, Department of Orthopedics, Wonmi-gu, Bucheon-si (Korea, Republic of); Lee, Bo Ra [Soonchunhyang University Bucheon Hospital, Department of Biomedical Statistics, Wonmi-gu, Bucheon-si (Korea, Republic of); Jeon, Chan Hong [Soonchunhyang University Bucheon Hospital, Division of Rheumatology, Department of Internal Medicine, Wonmi-gu, Bucheon-si (Korea, Republic of)

    2016-07-15

    To determine the accuracy of a three-dimensional (3D) T2-weighted fast spin-echo (FSE) magnetic resonance (MR) sequence compared with two-dimensional (2D) sequence for diagnosing anterior talofibular ligament (ATFL) tears, chondral lesion of the talus (CLT) and os subfibulare/avulsion fracture of the distal fibula (OSF). Thirty-five patients were included, who had undergone ankle MRI with 3D T2-weighted FSE and 2D T2-weighted FSE sequences, as well as subsequent ankle arthroscopy, between November 2013 and July 2014. Each MR imaging sequence was independently scored by two readers retrospectively for the presence of ATFL tears, CLT and OSF. The area under the receiver operating curve (AUC) was compared to determine the discriminatory power of the two image sequences. Interobserver agreement was expressed as unweighted kappa value. Arthroscopic findings confirmed 21 complete tears of the ATFL, 14 partial tears of the ATFL, 17 CLTs and 7 OSFs. There were no significant differences in the diagnoses of ATFL tears (p = 0.074-0.501), CLT (p = 0.090-0.450) and OSF (p = 0.317) obtained from the 2D and 3D sequences by either reader. The interobserver agreement rates between two readers using the 3D T2-weighted FSE sequence versus those obtained with the 2D sequence were substantial (κ = 0.659) versus moderate (κ = 0.553) for ATFL tears, moderate (κ = 0.499) versus substantial (κ = 0.676) for CLT and substantial (κ = 0.621) versus substantial (κ = 0.689) for OSF. Three-dimensional isotropic T2-weighted FSE MRI of the ankle resulted in no statistically significant difference in diagnostic performance compared to two-dimensional T2-weighted FSE MRI in the evaluation of ATFL tears, CLTs and OSFs. (orig.)

  6. MRI of the anterior talofibular ligament, talar cartilage and os subfibulare: Comparison of isotropic resolution 3D and conventional 2D T2-weighted fast spin-echo sequences at 3.0 T

    International Nuclear Information System (INIS)

    Yi, Jisook; Cha, Jang Gyu; Lee, Young Koo; Lee, Bo Ra; Jeon, Chan Hong

    2016-01-01

    To determine the accuracy of a three-dimensional (3D) T2-weighted fast spin-echo (FSE) magnetic resonance (MR) sequence compared with two-dimensional (2D) sequence for diagnosing anterior talofibular ligament (ATFL) tears, chondral lesion of the talus (CLT) and os subfibulare/avulsion fracture of the distal fibula (OSF). Thirty-five patients were included, who had undergone ankle MRI with 3D T2-weighted FSE and 2D T2-weighted FSE sequences, as well as subsequent ankle arthroscopy, between November 2013 and July 2014. Each MR imaging sequence was independently scored by two readers retrospectively for the presence of ATFL tears, CLT and OSF. The area under the receiver operating curve (AUC) was compared to determine the discriminatory power of the two image sequences. Interobserver agreement was expressed as unweighted kappa value. Arthroscopic findings confirmed 21 complete tears of the ATFL, 14 partial tears of the ATFL, 17 CLTs and 7 OSFs. There were no significant differences in the diagnoses of ATFL tears (p = 0.074-0.501), CLT (p = 0.090-0.450) and OSF (p = 0.317) obtained from the 2D and 3D sequences by either reader. The interobserver agreement rates between two readers using the 3D T2-weighted FSE sequence versus those obtained with the 2D sequence were substantial (κ = 0.659) versus moderate (κ = 0.553) for ATFL tears, moderate (κ = 0.499) versus substantial (κ = 0.676) for CLT and substantial (κ = 0.621) versus substantial (κ = 0.689) for OSF. Three-dimensional isotropic T2-weighted FSE MRI of the ankle resulted in no statistically significant difference in diagnostic performance compared to two-dimensional T2-weighted FSE MRI in the evaluation of ATFL tears, CLTs and OSFs. (orig.)

  7. MR imaging of cranial nerve lesions using six different high-resolution T1- and T2(*)-weighted 3D and 2D sequences

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, J.; Held, P.; Strotzer, M.; Voelk, M.; Nitz, W.R.; Dorenbeck, U.; Feuerbach, S. [Univ. Hospital of Regensburg (Germany). Dept. of Diagnostic Radiology; Stamato, S. [Univ. of California, San Diego, CA (United States). Dept. of Radiology

    2002-07-01

    Purpose: To find a suitable high-resolution MR protocol for the visualization of lesions of all 12 cranial nerves. Material and Methods: Thirty-eight pathologically changed cranial nerves (17 patients) were studied with MR imaging at 1.5T using 3D T2*-weighted CISS, T1-weighted 3D MP-RAGE (without and with i.v. contrast medium), T2-weighted 3D TSE, T2-weighted 2D TSE and T1-weighted fat saturation 2D TSE sequences. Visibility of the 38 lesions of the 12 cranial nerves in each sequence was evaluated by consensus of two radiologists using an evaluation scale from 1 (excellently visible) to 4 (not visible). Results: The 3D CISS sequence provided the best resolution of the cranial nerves and their lesions when surrounded by CSF. In nerves which were not surrounded by CSF, the 2D T1-weighted contrast-enhanced fat suppression technique was the best sequence. Conclusions: A combination of 3D CISS, the 2D T1-weighted fat suppressed sequence and a 3D contrast-enhanced MP-RAGE proved to be the most useful sequence to visualize all lesions of the cranial nerves. For the determination of enhancement, an additional 3D MP-RAGE sequence without contrast medium is required. This sequence is also very sensitive for the detection of hemorrhage.

  8. MR imaging of cranial nerve lesions using six different high-resolution T1- and T2(*)-weighted 3D and 2D sequences

    International Nuclear Information System (INIS)

    Seitz, J.; Held, P.; Strotzer, M.; Voelk, M.; Nitz, W.R.; Dorenbeck, U.; Feuerbach, S.; Stamato, S.

    2002-01-01

    Purpose: To find a suitable high-resolution MR protocol for the visualization of lesions of all 12 cranial nerves. Material and Methods: Thirty-eight pathologically changed cranial nerves (17 patients) were studied with MR imaging at 1.5T using 3D T2*-weighted CISS, T1-weighted 3D MP-RAGE (without and with i.v. contrast medium), T2-weighted 3D TSE, T2-weighted 2D TSE and T1-weighted fat saturation 2D TSE sequences. Visibility of the 38 lesions of the 12 cranial nerves in each sequence was evaluated by consensus of two radiologists using an evaluation scale from 1 (excellently visible) to 4 (not visible). Results: The 3D CISS sequence provided the best resolution of the cranial nerves and their lesions when surrounded by CSF. In nerves which were not surrounded by CSF, the 2D T1-weighted contrast-enhanced fat suppression technique was the best sequence. Conclusions: A combination of 3D CISS, the 2D T1-weighted fat suppressed sequence and a 3D contrast-enhanced MP-RAGE proved to be the most useful sequence to visualize all lesions of the cranial nerves. For the determination of enhancement, an additional 3D MP-RAGE sequence without contrast medium is required. This sequence is also very sensitive for the detection of hemorrhage

  9. Comparison of fast spin echo, fast multiplanner spoiled gradient recalled and conventional T1 and T2 weighted imaging for experimentally induced hepatic tumors in rats

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myeong Jin; Lee, Jong Tae; Suh, Jin Suk; Choi, Pil Sik; Lee, Yeon Hee; Yoo, Hyung Sik; Kim, Ki Whang [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1994-10-15

    To compare the ability of tumor detection and the lesion conspicuity between T1- and T2-weighted fast scanning sequence and T1- and T2-weighted conventional spin echo techniques in MR imaging of hepatic tumors. Hepatic tumors were induced on 13 male Sprague-Dawley rats by feeding 3'-methyl-dimethylethyl aminoazobenzene mixed with Miller's III formula for 12 weeks. MR images were obtained with 1.5 T magnet with dual TMJ coil(Sigma, GE Medical systems, Milwaukee, USA). Animals were anesthetized with 150 mg/kg of ketamine hydrochloride. T2 weighted fast spin echo(FSE), conventional spin echo(CSE) T2- and T1WI, fast multiplanner spoiled gradient recalled(FMPSPGR) imaging were obtained. Number of detected tumors and contrast-to-noise ratio of the tumors were compared for each sequence. Overall 110 tumors were developed. 75% of the tumors were detected on FSE. 65% on FMPSPGR, 41% on conventional T2WI, and 41% on T1WI images. For tumors more than 5 mm in diameter, sensitivity was 88% on FMPSPGR, 65% on conventional T2WI, and 81% on T1WI images respectively. CNR of the tumor was 28.94 {+-} 21.6 on FSE, 13.57 {+-} 8.64 on FMPSPGR, 12.62 {+-} 10.65 on CSE T2WI, and 9.47 {+-} 8.05 on CSE T1WI images, which was significantly high on FSE(p<0.05). Fast spin echo T2WI shows highest sensitivity and tumor-to-liver contrast. FMPSPGR imaging is also favorably comparable with conventional T1WI. Therefore, these two pulse sequences can be useful in clinical condition for hepatic MR imaging.

  10. The usefulness of T2-weighted MR urography and contrast enhanced MR urography in the evaluation of obstructive uropathy: comparisonal study with antegrade pyelography

    International Nuclear Information System (INIS)

    Oh, Chang Hoon; Lee, Jeong Min; Jin, Kong Yong; Chung, Gyung Ho; Cho, Seung Il; Lee, Sang Hun; Kim, Young Kon; Oh, Gyung Jae

    2002-01-01

    To compare the efficacy of contrast-enhanced and T2-weighted magnetic resonance urography (MRU) for the depiction of obstruction and evaluation of the causes of obstructive uropathy with that of antegrade pyelography. Twenty-five patients with obstructive uropathy who underwent percutaneous nephrostomy (PCN) and antegrade pyelography( AGP) were included in the study. We performed MR urography, comprising half-Fourier acquisition single-shot turbo spin-echo (HASTE) T2- weighted imaging and 3-D fast imaging with steady state precession (3-D FISP) T1-weighted imaging after gadolinium enhancement and compared the quality of the images of both the HASTE and 3-D FISP MRU technique in terms of their depiction of the dilated pelvocalyceal system, and the level, type, and causes of obstruction. In terms of anatomical depiction of the pelvocalyceal system (p=0.002) and the causes of obstruction (p=0.003). T1-weighted MRU using 3D-FISP was significantly better than T2-weighted MRU using the HASTE sequence. Regarding level of obstruction, T2-weighted MRU using the HASTE sequence and contrast enhanced T1-weighted MRU using 3D-FISP showed an accuracy of 76% (19/25) and 84% (21/25), respectively. In terms of type of obstruction, the accuracy of T2-weighted MRU and T1-weighted CEMRU was 72% (18/25) and 88% (22/25), respectively. T2-weighted MRU and Ta-weighted CEMRU provided both anatomical information and that relating to impaired renal function. The two modelities played a complementary role and their use could decrease the unnecessary use of invasive diagnostic examination for the evaluation of obstructive uropathy

  11. Eu, Gd-Codoped Yttria Nanoprobes for Optical and T1-Weighted Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Timur Sh Atabaev

    2017-02-01

    Full Text Available Nanoprobes with multimodal functionality have attracted significant interest recently because of their potential applications in nanomedicine. This paper reports the successful development of lanthanide-doped Y2O3 nanoprobes for potential applications in optical and magnetic resonance (MR imaging. The morphology, structural, and optical properties of these nanoprobes were characterized by transmission electron microscope (TEM, field emission scanning electron microscope (FESEM, X-ray diffraction (XRD, energy-dispersive X-ray (EDX, and photoluminescence (PL. The cytotoxicity test showed that the prepared lanthanide-doped Y2O3 nanoprobes have good biocompatibility. The obvious contrast enhancement in the T1-weighted MR images suggested that these nanoprobes can be used as a positive contrast agent in MRI. In addition, the clear fluorescence images of the L-929 cells incubated with the nanoprobes highlight their potential for optical imaging. Overall, these results suggest that prepared lanthanide-doped Y2O3 nanoprobes can be used for simultaneous optical and MR imaging.

  12. High signals in the uterine cervix on T2-weighted MRI sequences

    International Nuclear Information System (INIS)

    Graef, De M.; Karam, R.; Daclin, P.Y.; Rouanet, J.P.; Juhan, V.; Maubon, A.J.

    2003-01-01

    The aim of this pictorial review was to illustrate the normal cervix appearance on T2-weighted images, and give a review of common or less common disorders of the uterine cervix that appear as high signal intensity lesions on T2-weighted sequences. Numerous aetiologies dominated by cervical cancer are reviewed and discussed. This gamut is obviously incomplete; however, radiologists who perform MR women's imaging should perform T2-weighted sequences in the sagittal plane regardless of the indication for pelvic MR. Those sequences will diagnose some previously unknown cervical cancers as well as many other unknown cervical or uterine lesions. (orig.)

  13. Extent of myocardium at risk for left anterior descending artery, right coronary artery, and left circumflex artery occlusion depicted by contrast-enhanced steady state free precession and T2-weighted short tau inversion recovery magnetic resonance imaging

    DEFF Research Database (Denmark)

    Nordlund, David; Heiberg, Einar; Carlsson, Marcus

    2016-01-01

    Background - Contrast-enhanced steady state free precession (CE-SSFP) and T2-weighted short tau inversion recovery (T2-STIR) have been clinically validated to estimate myocardium at risk (MaR) by cardiovascular magnetic resonance while using myocardial perfusion single-photon emission computed...... tomography as reference standard. Myocardial perfusion single-photon emission computed tomography has been used to describe the coronary perfusion territories during myocardial ischemia. Compared with myocardial perfusion single-photon emission computed tomography, cardiovascular magnetic resonance offers...... to show the main coronary perfusion territories using CE-SSFP and T2-STIR. The good agreement between CE-SSFP and T2-STIR from this study and myocardial perfusion single-photon emission computed tomography from previous studies indicates that these 3 methods depict MaR accurately in individual patients...

  14. Differentiating benign and malignant breast lesions with T2*-weighted first pass perfusion imaging

    International Nuclear Information System (INIS)

    Kvistad, K.A.; Smenes, E.; Haraldseth, O.; Lundgren, S.; Fjoesne, H.E.; Smethurst, H.B.

    1999-01-01

    Purpose: Invasive breast carcinomas and fibroadenomas are often difficult to differentiate in dynamic contrast-enhanced T1-weighted MR imaging of the breast, because both tumors can enhance strongly after contrast injection. The purpose of this study was to evaluate whether the addition of T2*-weighted first pass perfusion imaging can increase the differentiation of malignant from benign lesions. Material and Methods: Nine patients with invasive carcinomas and 10 patients with contrast enhancing fibroadenomas were examined by a dynamic contrast-enhanced T1-weighted 3D sequence immediately followed by a single slice T2*-weighted first pass perfusion sequence positioned in the contrast-enhancing lesion. Results: The carcinomas and the fibroadenomas were impossible to differentiate based on the contrast enhancement characteristics in the T1-weighted sequence. The signal loss in the T2*-weighted perfusion sequence was significantly stronger in the carcinomas than in the fibroadenomas (p=0.0004). Conclusion: Addition of a T2*-weighted first pass perfusion sequence with a high temporal resolution can probably increase the differentiation of fibroadenomas from invasive carcinomas in contrast-enhanced MR imaging of the breast. (orig.)

  15. A Prospective Evaluation of T2-Weighted First-Pass Perfusion MR Imaging In Diagnosing Breast Neoplasms

    Institute of Scientific and Technical Information of China (English)

    XiaoJuanUu; RenyouZhai; TaoJiang; LiWang

    2004-01-01

    OBJECTIVE To compare the results from breast cancer patients who undergo T2-weighted first-pass perfusion imaging after dynamic contrast-enhanced T1-weighted imaging during the same examination,and to evaluate if T2-weighted imaging can provide additional diagnostic information over that obtained with Tl-weiahted imaaina.METHODS Twenty-nine patients with breast lesions verified by pathology (benign 12, malignant 17) underwent MR imaging with dynamic contrast-enhanced Tl-weighted imaging of the entire breasts,immediately followed by 6-sections of T2-weighted first-pass perfusion imaging of the lesions. The diagnostic indices were acquired by individual 3D Tl-weighted enhancement rate criterion and the T2 signalintensity loss rate criterion. The sensitivity and specificity were calculated and the 2 methods were compared.RESULTS With the dynamic contrast-enhanced T1-weighted imaging there was a significant differences breast lesions (t=2.563, P=0.016)overlap between the signal intensitybetween the benign and malignant However we found a considerable increase in the carcinomas and thatin the benign lesions, for a sensitivity of 94% and a specificity of 25%.With T2-weighted first-pass perfusion imaging, there was a very significant difference between the benign and malignant breast lesions(t=4.777,P<0.001), and the overlap between the signal intensity decrease in the carcinomas and that of the benign lesions on the T2-weighted images was less pronounced than the overlap in the T1-weighted images, for a sensitivity of 88% and a specificity of 75%.CONCLUSION T2-weighted first-pass perfusion imaging may help differentiate between benign and malignant breast lesions with a higher level of specificity. The combination of T1-weighted and T2-weighted imaging is feasible in a single patient examination and may improve breast MR imaging.

  16. 3D T2-weighted imaging to shorten multiparametric prostate MRI protocols.

    Science.gov (United States)

    Polanec, Stephan H; Lazar, Mathias; Wengert, Georg J; Bickel, Hubert; Spick, Claudio; Susani, Martin; Shariat, Shahrokh; Clauser, Paola; Baltzer, Pascal A T

    2018-04-01

    To determine whether 3D acquisitions provide equivalent image quality, lesion delineation quality and PI-RADS v2 performance compared to 2D acquisitions in T2-weighted imaging of the prostate at 3 T. This IRB-approved, prospective study included 150 consecutive patients (mean age 63.7 years, 35-84 years; mean PSA 7.2 ng/ml, 0.4-31.1 ng/ml). Two uroradiologists (R1, R2) independently rated image quality and lesion delineation quality using a five-point ordinal scale and assigned a PI-RADS score for 2D and 3D T2-weighted image data sets. Data were compared using visual grading characteristics (VGC) and receiver operating characteristics (ROC)/area under the curve (AUC) analysis. Image quality was similarly good to excellent for 2D T2w (mean score R1, 4.3 ± 0.81; R2, 4.7 ± 0.83) and 3D T2w (mean score R1, 4.3 ± 0.82; R2, 4.7 ± 0.69), p = 0.269. Lesion delineation was rated good to excellent for 2D (mean score R1, 4.16 ± 0.81; R2, 4.19 ± 0.92) and 3D T2w (R1, 4.19 ± 0.94; R2, 4.27 ± 0.94) without significant differences (p = 0.785). ROC analysis showed an equivalent performance for 2D (AUC 0.580-0.623) and 3D (AUC 0.576-0.629) T2w (p > 0.05, respectively). Three-dimensional acquisitions demonstrated equivalent image and lesion delineation quality, and PI-RADS v2 performance, compared to 2D in T2-weighted imaging of the prostate. Three-dimensional T2-weighted imaging could be used to considerably shorten prostate MRI protocols in clinical practice. • 3D shows equivalent image quality and lesion delineation compared to 2D T2w. • 3D T2w and 2D T2w image acquisition demonstrated comparable diagnostic performance. • Using a single 3D T2w acquisition may shorten the protocol by 40%. • Combined with short DCE, multiparametric protocols of 10 min are feasible.

  17. Application of fast spin-echo T[sub 2]-weighted imaging for examination of the neurocranium. Comparison with the conventional T[sub 2]-weighted spin-echo sequence. Die Anwendung der T[sub 2]-gewichteten Turbo-Spin-Echo-Sequenz zur Untersuchung des Neurokraniums. Vergleich mit der konventionellen T[sub 2]-gewichteten Spin-Echo-Sequenz

    Energy Technology Data Exchange (ETDEWEB)

    Siewert, C. (Strahlenklinik und Poliklinik, Universitaets-Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany)); Hosten, N. (Strahlenklinik und Poliklinik, Universitaets-Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany)); Felix, R. (Strahlenklinik und Poliklinik, Universitaets-Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany))

    1994-07-01

    T[sub 2]-weighted spin-echo imaging is the standard screening procedure in MR imaging of the neutrocranium. We evaluated fast spin-echo T[sub 2]-weighted imaging (TT[sub 2]) of the neurocranium in comparison to conventional spin-echo T[sub 2]-weighted imaging (T[sub 2]). Signal-to-noise and contrast-to-noise ratio of normal brain tissues (basal ganglia, grey and white matter, CSF fluid) and different pathologies were calculated. Signal-to-noise ratio and contrast-to-noise ratio were significantly higher than TT[sub 2] than in T[sub 2] (with the exception of grey-to-white matter contrast). Tissues with increased content of water protons (mobile protons) showed the highest contrast to surrounding tissues. The increased signal intensity of fat must be given due attention in fatty lesions. Because the contrast-to-noise ratio between white matter and basal ganglia is less in TT[sub 2], Parkinson patients have to be examined by conventional T[sub 2]. If these limitations are taken into account, fast spin-echo T[sub 2]-weighted imaging is well appropriate for MR imaging of the neurocranium, resulting in heavy T[sub 2]-weighting achieved in a short acquisition time. (orig.)

  18. Hippocampal Microbleed on a Post-Mortem T2*-Weighted Gradient-Echo 7.0-Tesla Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    J. De Reuck

    2011-09-01

    Full Text Available The present post-mortem study of a brain from an Alzheimer patient showed on a T2*-weighted gradient-echo 7.0-T MRI of a coronal brain section a hyposignal in the hippocampus, suggesting a microbleed. On the corresponding histological examination, only iron deposits around the granular cellular layer and in blood vessel walls of the hippocampus were observed without evidence of a bleeding. This case report illustrates that the detection of microbleeds on MRI has to be interpreted with caution.

  19. Interactive thresholded volumetry of abdominal fat using breath-hold T1-weighted magnetic resonance imaging

    International Nuclear Information System (INIS)

    Wittsack, H.J.; Cohnen, M.; Jung, G.; Moedder, U.; Poll, L.; Kapitza, C.; Heinemann, L.

    2006-01-01

    Purpose: development of a feasible and reliable method for determining abdominal fat using breath-hold T1-weighted magnetic resonance imaging. Materials and methods: the high image contrast of T1-weighted gradient echo MR sequences makes it possible to differentiate between abdominal fat and non-fat tissue. To obtain a high signal-to-noise ratio, the measurements are usually performed using phased array surface coils. Inhomogeneity of the coil sensitivity leads to inhomogeneity of the image intensities. Therefore, to examine the volume of abdominal fat, an automatic algorithm for intensity correction must be implemented. The analysis of the image histogram results in a threshold to separate fat from other tissue. Automatic segmentation using this threshold results directly in the fat volumes. The separation of intraabdominal and subcutaneous fat is performed by interactive selection in a last step. Results: the described correction of inhomogeneity allows for the segmentation of the images using a global threshold. The use of semiautomatic interactive volumetry makes the analysis more subjective. The variance of volumetry between observers was 4.6%. The mean time for image analysis of a T1-weighted investigation lasted less than 6 minutes. Conclusion: the described method facilitates reliable determination of abdominal fat within a reasonable period of time. Using breath-hold MR sequences, the time of examination is less than 5 minutes per patient. (orig.)

  20. The value of diffusion-weighted imaging in combination with T2-weighted imaging for rectal cancer detection

    International Nuclear Information System (INIS)

    Rao Shengxiang; Zeng Mengsu; Chen Caizhong; Li Renchen; Zhang Shujie; Xu Jianming; Hou Yingyong

    2008-01-01

    Objective: To evaluate the clinical value of diffusion-weighted imaging (DWI) in combination with T 2 -weighted imaging (T 2 WI) for the detection of rectal cancer as compared with T 2 WI alone. Materials and methods: Forty-five patients with rectal cancer and 20 without rectal cancer underwent DWI with parallel imaging and T 2 WI on a 1.5 T scanner. Images were independently reviewed by two readers blinded to the results to determine the detectability of rectal cancer. The detectability of T 2 W imaging without and with DW imaging was assessed by means of receiver operating characteristic analysis. The interobserver agreement between the two readers was calculated with kappa statistics. Results: The ROC analysis showed that each of two readers achieved more accurate results with T 2 W imaging combined with DW imaging than with T 2 W imaging alone significantly. The A z values for the two readers for each T 2 WI and T 2 WI combined with DWI were 0.918 versus 0.991 (p = 0.0494), 0.934 versus 0.997 (p = 0.0475), respectively. The values of kappa were 0.934 for T 2 WI and 0.948 for T 2 WI combined with DWI between the two readers. Conclusion: The addition of DW imaging to conventional T 2 W imaging provides better detection of rectal cancer

  1. T2-weighted vs. intrathecal contrast-enhanced MR cisternography in the evaluation of CSF rhinorrhea

    International Nuclear Information System (INIS)

    Ecin, Gaye; Oner, A. Yusuf; Tokgoz, Nil; Ucar, Murat; Tali, Turgut; Aykol, Sukru

    2013-01-01

    Background: Endoscopic surgical approach is being more widely used in the treatment of cerebrospinal fluid (CSF) rhinorrhea. Accurate localization of CSF fistulas prior to surgery is essential in increasing the success of dural repair and in decreasing negative or recurrent explorations. Purpose: To evaluate and compare intrathecal contrast medium-enhanced magnetic resonance cisternography (CEMRC) with T2-weighted MR cisternography (T2MRC) in identifying the presence and site of CSF rhinorrhea. Material and Methods: Sixty patients with suspected CSF rhinorrhea underwent MR cisternography including intrathecally enhanced fat-suppressed T1WI in three orthogonal planes and T2WI in the coronal plane. Both set of images were reviewed by two blinded radiologists for the presence and location of CSF leakage. Imaging data were compared with surgical findings and/or beta-2 transferrin testing. Results: With surgery proven CSF leakage in 20 instances as reference, CEMRC detected 18 (90%), whereas T2MRC reported only 13 (65%) correctly. Overall, sensitivity, specificity, positive predictive value, and negative predictive value in detecting CSF fistulas were 92%, 80%, 76%, and 93% for CEMRC, and 56%, 77%, 64%, and 71% for T2MRC, respectively. Conclusion: The minimally invasive CEMRC is an effective method with higher sensitivity and specificity than T2MRC in the evaluation of CSF fistulas

  2. MR signal of the solid portion of pilocytic astrocytoma on T2-weighted images: is it useful for differentiation from medulloblastoma?

    International Nuclear Information System (INIS)

    Arai, Kiyokazu; Yagi, Akiko; Taketomi-Takahashi, Ayako; Morita, Hideo; Koyama, Yoshinori; Endo, Keigo; Sato, Noriko; Aoki, Jun; Oba, Hiroshi; Ishiuchi, Shogo; Saito, Nobuhito

    2006-01-01

    Background and purpose: Although imaging features of cerebellar pilocytic astrocytoma and medulloblastoma have been described in many texts, original comparisons of magnetic resonance intensity between these two tumours are limited. In the present study the results of magnetic resonance imaging (MRI) were reviewed, focusing especially on the signal intensity of the solid portion of these neoplasms. Methods: MR images of ten cerebellar pilocytic astrocytomas and ten medulloblastomas were reviewed. The signal intensities of the solid components were graded on a scale of 1 to 5, with higher scores indicating a signal intensity closer to that of water. The degree of enhancement, tumour cysts and peripheral oedema were evaluated on MR images. When the solid portion was heterogeneous (i.e. mixed signal intensity or degree of enhancement), the dominant area was selected for evaluation. On T2-weighted images, the signal intensity of the solid portion was equal to that of cerebrospinal fluid (CSF) in 50% of pilocytic astrocytomas. No medulloblastomas showed such hyperintensity. Most medulloblastomas (80%) were isointense to grey matter. On T1-weighted images, the signal intensity varied widely in pilocytic astrocytomas; however, all medulloblastomas were iso- or hypointense to grey matter. The MR enhancement pattern, cystic component and peripheral oedema all varied in both tumour types and no specific features were identified. A signal intensity of the solid portion isointense to CSF on T2-weighted images was characteristic of cerebellar pilocytic astrocytomas; this was not observed in medulloblastomas. Attention to T2-weighted imaging of the solid portions of a tumour is easy and helpful in differentiating between cerebellar pilocytic astrocytoma and medulloblastoma. (orig.)

  3. High spatial resolution and temporally resolved T2* mapping of normal human myocardium at 7.0 Tesla: an ultrahigh field magnetic resonance feasibility study.

    Directory of Open Access Journals (Sweden)

    Fabian Hezel

    Full Text Available Myocardial tissue characterization using T(2(* relaxation mapping techniques is an emerging application of (preclinical cardiovascular magnetic resonance imaging. The increase in microscopic susceptibility at higher magnetic field strengths renders myocardial T(2(* mapping at ultrahigh magnetic fields conceptually appealing. This work demonstrates the feasibility of myocardial T(2(* imaging at 7.0 T and examines the applicability of temporally-resolved and high spatial resolution myocardial T(2(* mapping. In phantom experiments single cardiac phase and dynamic (CINE gradient echo imaging techniques provided similar T(2(* maps. In vivo studies showed that the peak-to-peak B(0 difference following volume selective shimming was reduced to approximately 80 Hz for the four chamber view and mid-ventricular short axis view of the heart and to 65 Hz for the left ventricle. No severe susceptibility artifacts were detected in the septum and in the lateral wall for T(2(* weighting ranging from TE = 2.04 ms to TE = 10.2 ms. For TE >7 ms, a susceptibility weighting induced signal void was observed within the anterior and inferior myocardial segments. The longest T(2(* values were found for anterior (T(2(* = 14.0 ms, anteroseptal (T(2(* = 17.2 ms and inferoseptal (T(2(* = 16.5 ms myocardial segments. Shorter T(2(* values were observed for inferior (T(2(* = 10.6 ms and inferolateral (T(2(* = 11.4 ms segments. A significant difference (p = 0.002 in T(2(* values was observed between end-diastole and end-systole with T(2(* changes of up to approximately 27% over the cardiac cycle which were pronounced in the septum. To conclude, these results underscore the challenges of myocardial T(2(* mapping at 7.0 T but demonstrate that these issues can be offset by using tailored shimming techniques and dedicated acquisition schemes.

  4. SU-F-R-35: Repeatability of Texture Features in T1- and T2-Weighted MR Images

    International Nuclear Information System (INIS)

    Mahon, R; Weiss, E; Karki, K; Hugo, G; Ford, J

    2016-01-01

    Purpose: To evaluate repeatability of lung tumor texture features from inspiration/expiration MR image pairs for potential use in patient specific care models and applications. Repeatability is a desirable and necessary characteristic of features included in such models. Methods: T1-weighted Volumetric Interpolation Breath-Hold Examination (VIBE) and/or T2-weighted MRI scans were acquired for 15 patients with non-small cell lung cancer before and during radiotherapy for a total of 32 and 34 same session inspiration-expiration breath-hold image pairs respectively. Bias correction was applied to the VIBE (VIBE-BC) and T2-weighted (T2-BC) images. Fifty-nine texture features at five wavelet decomposition ratios were extracted from the delineated primary tumor including: histogram(HIST), gray level co-occurrence matrix(GLCM), gray level run length matrix(GLRLM), gray level size zone matrix(GLSZM), and neighborhood gray tone different matrix (NGTDM) based features. Repeatability of the texture features for VIBE, VIBE-BC, T2-weighted, and T2-BC image pairs was evaluated by the concordance correlation coefficient (CCC) between corresponding image pairs, with a value greater than 0.90 indicating repeatability. Results: For the VIBE image pairs, the percentage of repeatable texture features by wavelet ratio was between 20% and 24% of the 59 extracted features; the T2-weighted image pairs exhibited repeatability in the range of 44–49%. The percentage dropped to 10–20% for the VIBE-BC images, and 12–14% for the T2-BC images. In addition, five texture features were found to be repeatable in all four image sets including two GLRLM, two GLZSM, and one NGTDN features. No single texture feature category was repeatable among all three image types; however, certain categories performed more consistently on a per image type basis. Conclusion: We identified repeatable texture features on T1- and T2-weighted MRI scans. These texture features should be further investigated for use

  5. SU-F-R-35: Repeatability of Texture Features in T1- and T2-Weighted MR Images

    Energy Technology Data Exchange (ETDEWEB)

    Mahon, R; Weiss, E; Karki, K; Hugo, G [Virginia Commonwealth University, Richmond, VA (United States); Ford, J [University of Miami Miller School of Medicine, Miami, FL (United States)

    2016-06-15

    Purpose: To evaluate repeatability of lung tumor texture features from inspiration/expiration MR image pairs for potential use in patient specific care models and applications. Repeatability is a desirable and necessary characteristic of features included in such models. Methods: T1-weighted Volumetric Interpolation Breath-Hold Examination (VIBE) and/or T2-weighted MRI scans were acquired for 15 patients with non-small cell lung cancer before and during radiotherapy for a total of 32 and 34 same session inspiration-expiration breath-hold image pairs respectively. Bias correction was applied to the VIBE (VIBE-BC) and T2-weighted (T2-BC) images. Fifty-nine texture features at five wavelet decomposition ratios were extracted from the delineated primary tumor including: histogram(HIST), gray level co-occurrence matrix(GLCM), gray level run length matrix(GLRLM), gray level size zone matrix(GLSZM), and neighborhood gray tone different matrix (NGTDM) based features. Repeatability of the texture features for VIBE, VIBE-BC, T2-weighted, and T2-BC image pairs was evaluated by the concordance correlation coefficient (CCC) between corresponding image pairs, with a value greater than 0.90 indicating repeatability. Results: For the VIBE image pairs, the percentage of repeatable texture features by wavelet ratio was between 20% and 24% of the 59 extracted features; the T2-weighted image pairs exhibited repeatability in the range of 44–49%. The percentage dropped to 10–20% for the VIBE-BC images, and 12–14% for the T2-BC images. In addition, five texture features were found to be repeatable in all four image sets including two GLRLM, two GLZSM, and one NGTDN features. No single texture feature category was repeatable among all three image types; however, certain categories performed more consistently on a per image type basis. Conclusion: We identified repeatable texture features on T1- and T2-weighted MRI scans. These texture features should be further investigated for use

  6. Detection of hyperacute parenchymal hemorrhage of the brain using echo-planar T2{sup *}-weighted and diffusion-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Wiesmann, M. [Dept. of Radiology, Medizinische Universitaet zu Luebeck (Germany); Mayer, T.E.; Yousry, I.; Brueckmann, H. [Dept. of Neuroradiology, Klinikum Grosshadern, Ludwig-Maximilians-Universitaet, Muenchen (Germany); Hamann, G.F. [Dept. of Neurology, Klinikum Grosshadern, Ludwig-Maximilians-Universitaet, Muenchen (Germany)

    2001-05-01

    We investigated the usefulness of echo-planar imaging (EPI) as well as T2{sup *}-weighted and diffusion-weighted MRI (DWI) to identify hyperacute hemorrhage (within 24 h after ictus) in the brain. Seven patients were examined 3.5 to 24 h after onset of symptoms using a whole-body 1.5-T MR system. Two diffusion-weighted sequences were run to obtain isotropic and anisotropic diffusion images. Apparent diffusion coefficients (ADC) were calculated from the isotropic diffusion images. All DWI images as well as the T2*-weighted EPI images showed the hematomas as either discrete, deeply hypointense homogeneous lesions, or as lesions of mixed signal intensity containing hypointense areas. We conclude that even in the early phase after hemorrhage, sufficient amounts of paramagnetic deoxyhemoglobin are present in intracerebral hemorrhages to cause hypointensity on EPI T2{sup *}-weighted and DWI images; thus, use of ultrafast EPI allows identification of intracerebral hemorrhage. (orig.)

  7. T2-weighted MRI-derived textural features reflect prostate cancer aggressiveness: preliminary results

    NARCIS (Netherlands)

    Nketiah, G.; Elschot, M.; Kim, E.; Teruel, J.R.; Scheenen, T.W.J.; Bathen, T.F.; Selnaes, K.M.

    2017-01-01

    PURPOSE: To evaluate the diagnostic relevance of T2-weighted (T2W) MRI-derived textural features relative to quantitative physiological parameters derived from diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) MRI in Gleason score (GS) 3+4 and 4+3 prostate cancers. MATERIALS AND METHODS:

  8. The interplay of T1- and T2-relaxation on T1-weighted MRI of hMSCs induced by Gd-DOTA-peptides.

    Science.gov (United States)

    Cao, Limin; Li, Binbin; Yi, Peiwei; Zhang, Hailu; Dai, Jianwu; Tan, Bo; Deng, Zongwu

    2014-04-01

    Three Gd-DOTA-peptide complexes with different peptide sequence are synthesized and used as T1 contrast agent to label human mesenchymal stem cells (hMSCs) for magnetic resonance imaging study. The peptides include a universal cell penetrating peptide TAT, a linear MSC-specific peptide EM7, and a cyclic MSC-specific peptide CC9. A significant difference in labeling efficacy is observed between the Gd-DOTA-peptides as well as a control Dotarem. All Gd-DOTA-peptides as well as Dotarem induce significant increase in T1 relaxation rate which is in favor of T1-weighted MR imaging. Gd-DOTA-CC9 yields the maximum labeling efficacy but poor T1 contrast enhancement. Gd-DOTA-EM7 yields the minimum labeling efficacy but better T1 contrast enhancement. Gd-DOTA-TAT yields a similar labeling efficacy as Gd-DOTA-CC9 and similar T1 contrast enhancement as Gd-DOTA-EM7. The underlying mechanism that governs T1 contrast enhancement effect is discussed. Our results suggest that T1 contrast enhancement induced by Gd-DOTA-peptides depends not only on the introduced cellular Gd content, but more importantly on the effect that Gd-DOTA-peptides exert on the T1-relaxation and T2-relaxation processes/rates. Both T1 and particularly T2 relaxation rate have to be taken into account to interpret T1 contrast enhancement. In addition, the interpretation has to be based on cellular instead of aqueous longitudinal and transverse relaxivities of Gd-DOTA-peptides. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Contrast-enhanced turbo spin-echo(TSE) T1-weighted imaging: improved contrast of enhancing lesions

    International Nuclear Information System (INIS)

    Choi, Sung Wook; Lee, Ghi Jai; Shim, Jae Chan; Lee, Young Ju; Jeong, Se Hyung; Kim, Ho kyun

    1997-01-01

    The purpose of this study was to evaluate the effect of contrast improvement of enhancing brain lesions by inherent magnetization transfer effect in turbo spin-echo(TSE)T1-weighted MR imaging. Twenty-six enhancing lesions of 19 patients were included in this study. Using a 1.0T superconductive MR unit, contrast-enhanced SE T1-weighted images(TR=3D600 msec, TE=3D12 msec, NEX=3D2, acquistition time=3D4min 27sec) and contrast-enhanced TSE T1-weighted images(TR=3D600 msec, TE=3D12, acquistition time=3D1min 44sec) were obtained. Signal intensities at enhancing lesions and adjacent white matter were measured in the same regions of both images. Signal-to-noise ratio(SNR) of enhancing lesions and adjacent white matter, and con-trast-to-noise ratio(CNR) and lesion-to-background contrast (LBC) of enhancing lesions were calculated and statistically analysed using the paired t-test. On contrast-enhanced TSE T1-weighted images, SNR of enhancing lesions and adjacent white matter decreased by 18%(p<0.01) and 32%(p<0.01), respectively, compared to contrast-enhanced SE T1-weighted images. CNR and LBC of enhancing lesions increased by 16%(p<0.05) and 66%(p<0.01), respectively. Due to the proposed inherent magnetization transfer effects in TSE imaging, con-trast-enhanced T1-weighted TSE images demonstrated a statistically significant improvement in CNR and LBC, compared to conventional contrast-enhanced T1-weighted SE images, and scan time was much shorter

  10. Comparison of 3D and 2D FSE T2-weighted MRI in the diagnosis of deep pelvic endometriosis: Preliminary results

    International Nuclear Information System (INIS)

    Bazot, M.; Stivalet, A.; Daraï, E.; Coudray, C.; Thomassin-Naggara, I.; Poncelet, E.

    2013-01-01

    Aim: To evaluate image quality and diagnostic accuracy of two- (2D) and three-dimensional (3D) T2-weighted magnetic resonance imaging (MRI) for the evaluation of deep infiltrating endometriosis (DIE). Materials and methods: One hundred and ten consecutive patients with suspicion of endometriosis were recruited at two institutions over a 5-month period. Twenty-three women underwent surgery, 18 had DIE at histology. Two readers independently evaluated 3D and 2D MRI for image quality and diagnosis of DIE. Descriptive analysis, chi-square test for categorical or nominal variables, McNemar test for comparison between 3D and 2D T2-weighted MRI, and weighted “statistics” for intra- and interobserver agreement were used for statistical analysis. Results: Both readers found that 3D yielded significantly lower image quality than 2D MRI (p < 0.0001). Acquisition time for 3D was significantly shorter than 2D MRI (p < 0.01). 3D offered similar accuracy to diagnose DIE compared to 2D MRI. For all locations of endometriosis, a high or variable intra-observer agreement was observed for reader 1 and 2, respectively. Conclusions: Despite a lower overall image quality, 3D provides significant time saving and similar accuracy than multiplanar 2D MRI in the diagnosis of specific DIE locations.

  11. Phase sensitive reconstruction of T1-weighted inversion recovery in the evaluation of the cervical cord lesions in multiple Sclerosis; is it similarly eligible in 1.5 T magnet fields?

    Science.gov (United States)

    Shayganfar, A; Sarrami, A H; Fathi, S; Shaygannejad, V; Shamsian, S

    2018-04-22

    In primary studies with 3 T Magnets, phase sensitive reconstruction of T1-weighted inversion recovery (PSIR) have showed ability to depict the cervical multiple sclerosis (MS) lesions some of which may not be detected by short tau inversion recovery (STIR). Regarding to more availability of 1.5 T MRI, this study was designed to evaluate the eligibility of PSIR in 1.5 T for detection of spinal cord MS lesions. In a study between September 2016 till March 2017 the patients with proven diagnosis of MS enrolled to the study. The standard protocol (sagittal STIR and T2W FSE and axial T2W FSE) as well as sagittal PSIR sequences were performed using a 1.5 T magnet. The images were studied and the lesions were localized and recorded as sharp or faint on each sequence. Of 25 patients (22 females and 3 males, with mean age of 33.5 ± 9.8 years and mean disease duration of 5.4 ± 3.9 years) 69 lesions in STIR, 53 lesions in T2W FSE, 47 lesions in Magnitude reconstruction of PSIR (Magnitude), and 30 lesions in phase sensitive (real) reconstruction PSIR were detected. A Wilcoxon signed-rank test showed STIR has a statistically significant higher detection rate of the plaques rather than other three sequences. (STIR and T2W FSE, Z = -4.000, p definition of the plaques rather than other three sequences. This study shows that in the setting of a 1.5 T magnet field, STIR significantly has a superiority over both of the PSIR reconstructions (i.e. real and magnitude) for the detection as well as the boundary definition of the cervical cord lesions of MS. These results have a good relevance to clinical practice by using MRI scanners and sequences routinely available, however, it is discrepant with other reports performed by 3 T Magnet fields. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Diffusion-weighted and T2-weighted MR imaging for colorectal liver metastases detection in a rat model at 7 T: a comparative study using histological examination as reference

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Mathilde; Ronot, Maxime; Vilgrain, Valerie; Beers, Bernard E. van [University Paris Diderot, Sorbonne Paris Cite, INSERM UMR 773, University Hospitals Paris Nord Val de Seine, Beaujon, Assistance Publique- Hopitaux de Paris, Laboratory of Physiological and Molecular Imaging of the Abdomen (IPMA) and Department of Radiology, Clichy Cedex (France); Maggiori, Leon; Panis, Yves [University Paris Diderot, Sorbonne Paris Cite, INSERM UMR 773, University Hospitals Paris Nord Val de Seine, Beaujon, Assistance Publique-Hopitaux de Paris, Department of Colorectal Surgery, Clichy (France); Paradis, Valerie [University Paris Diderot, Sorbonne Paris Cite, INSERM UMR 773, University Hospitals Paris Nord Val de Seine, Beaujon, Assistance Publique-Hopitaux de Paris, Department of Pathology, Clichy (France)

    2013-08-15

    To compare diffusion-weighted (DW) and T2-weighted MR imaging in detecting colorectal liver metastases in a rat model, using histological examination as a reference method. Eighteen rats had four liver injections of colon cancer cells. MR examinations at 7 T included FSE-T2-weighted imaging and SE-DW MR imaging (b = 0, 20 and 150 s/mm{sup 2}) and were analysed by two independent readers. Histological examination was performed on 0.4-mm slices. McNemar's test was used to compare the sensitivities and the Wilcoxon matched pairs test to compare the average number of false-positives per rat. One hundred and sixty-six liver metastases were identified on histological examination. The sensitivity in detecting liver metastases was significantly higher on DW MR than on T2-weighted images (99/166 (60 %) (reader 1) and 92/166 (55 %) (reader 2) versus 77/166 (46 %), P {<=} 0.001), without an increase in false-positives per rat (P = 0.773/P = 0.850). After stratification according to metastasis diameter, DW MR imaging had a significantly higher sensitivity than T2-weighted imaging only for metastases with a diameter (0.6-1.2 mm) similar to that of the spatial resolution of MR imaging in the current study. This MR study with histological correlations shows the higher sensitivity of DW relative to T2-weighted imaging at 7 T for detecting liver metastases, especially small ones. (orig.)

  13. Magnetic resonance imaging in Parkinson's disease; The evaluation of the width of pars compacta on T2 weighted image

    Energy Technology Data Exchange (ETDEWEB)

    Moriwaka, Fumio; Tashiro, Kunio; Itoh, Kazunori; Miyasaka, Kazuo [Hokkaido Univ., Sapporo (Japan). School of Medicine; Hamada, Takeshi

    1992-01-01

    The width of substantia nigra (SN) in 59 cases of idiopathic Parkinson's disease as well as 21 normal controls was analyzed by T2 weighted image (T2WI) of 1.5 Tesla high-field magnetic resonance image (MRI). All patients and controls underwent MRI with the spin-echo sequences used TR/TE: 3000/30 (short TE), and TR/TE: 3000/80 (long TE), in 5-mm-thick volumes. The width between the red nucleus and the cerebral peduncle showing low signal intensity areas was measured as that of SN and its ratio to the distance from the aqueduct to the midline of the cerebral peduncle was also measured. The calculated values of the width of SN and its ratio were analyzed by Mann-Whitney test. The significant reduction in the width of SN and its ratio in Parkinson's disease were disclosed below: the mean calculated values of the width of SN were 2.95{+-}0.51 mm in controls, 2.68{+-}0.99 mm in Parkinson's disase on long TE images (P<0.01), and the mean ratio of the width of SN were 13.58{+-}4.21% in controls, 10.52{+-}3.07% in Parkinson's disease on long TE images (P=0.0002). The narrowing of SN in Parkinson's disease was more prominent in men, and advanced cases with Yahr stage III and IV. Considering that the pars reticulata, which is normally containing iron, shows low signal intensity on long TE images, the width of pars compacta could be measured more precisely on this sequences. The evaluation of the ratio of SN in midbrain on long TE images seemed to be more sensitive than the calculated values in detecting the narrowing of SN and pars compacta in Parkinson's disease. (author).

  14. Low intensity areas observed T2-weighted magnetic resonance imaging of the cerebral cortex in various neurological diseases

    Energy Technology Data Exchange (ETDEWEB)

    Imon, Yukari [Hiroshima Univ. (Japan). School of Medicine

    1996-02-01

    We retrospectively studied magnetic resonance images of the brain in 158 patients (8 cases of amyotrophic lateral sclerosis, 16 cases of Alzheimer`s disease, 8 cases of Parkinson`s disease, 53 cases of multiple cerebral infarct, 20 cases of other central nervous system (CNS) diseases, and 53 cases without any CNS disease) to examine the appearance of T2-weighted low signal intensity areas (LIA) in the cerebral cortex. The age of subjects ranged from 36 to 85 years with the mean 65.0 and SD 9.9 years. LIA in the motor and sensory cortices, and brain atrophy were evaluated visually on axial images of the spin-echo sequence obtained with a 1.5 tesla system. The incidence of LIA in the motor cortex was significantly higher in all CNS diseases than in cases without any CNS disease, but not significantly different among CNS diseases. LIA in the motor cortex showed a correlation with age, temporal and parietal atrophy. The appearance of LIA in the sensory cortex correlated with that of LIA in the motor cortex, and parietal atrophy. These results suggest that LIA may appear according to age and be associated with the accumulation of nonheme iron in the cortex, especially in patients with CNS diseases. (author)

  15. Haralick textural features on T2 -weighted MRI are associated with biochemical recurrence following radiotherapy for peripheral zone prostate cancer.

    Science.gov (United States)

    Gnep, Khémara; Fargeas, Auréline; Gutiérrez-Carvajal, Ricardo E; Commandeur, Frédéric; Mathieu, Romain; Ospina, Juan D; Rolland, Yan; Rohou, Tanguy; Vincendeau, Sébastien; Hatt, Mathieu; Acosta, Oscar; de Crevoisier, Renaud

    2017-01-01

    To explore the association between magnetic resonance imaging (MRI), including Haralick textural features, and biochemical recurrence following prostate cancer radiotherapy. In all, 74 patients with peripheral zone localized prostate adenocarcinoma underwent pretreatment 3.0T MRI before external beam radiotherapy. Median follow-up of 47 months revealed 11 patients with biochemical recurrence. Prostate tumors were segmented on T 2 -weighted sequences (T 2 -w) and contours were propagated onto the coregistered apparent diffusion coefficient (ADC) images. We extracted 140 image features from normalized T 2 -w and ADC images corresponding to first-order (n = 6), gradient-based (n = 4), and second-order Haralick textural features (n = 130). Four geometrical features (tumor diameter, perimeter, area, and volume) were also computed. Correlations between Gleason score and MRI features were assessed. Cox regression analysis and random survival forests (RSF) were performed to assess the association between MRI features and biochemical recurrence. Three T 2 -w and one ADC Haralick textural features were significantly correlated with Gleason score (P recurrence (P recurrence following prostate cancer radiotherapy. 3 J. Magn. Reson. Imaging 2017;45:103-117. © 2016 International Society for Magnetic Resonance in Medicine.

  16. Fat-Suppressed T2* Sequences for Routine 3.0-Tesla Lumbar Spine Magnetic Resonance Imaging: A Preliminary Report

    International Nuclear Information System (INIS)

    McKinney, A. M.; Gadani, S.; Palmer, C. S.; Vidarsson, L.

    2008-01-01

    Background: Clear depiction of the ligamentum flavum on routine lumbar magnetic resonance imaging (MRI) is essential in accurately describing the extent of degenerative disease. In routine, noncontrast evaluations, focal fatty deposition or hemangiomas can be difficult to distinguish from malignant foci on fast spin-echo (FSE) T2-weighted images. Purpose: To describe the use of T2* fast field echo (T2FFE) in combination with spectral presaturation inversion recovery (SPIR) fat suppression for noncontrast, routine lumbar spine outpatient MR imaging at 3.0 Tesla (3T). Material and Methods: An axial gradient echo (GE) T2FFE sequence was combined with SPIR fat suppression (T2FFE-SPIR), via a 3T Philips Intera (Philips Medical Systems, Best, The Netherlands) scanner, and added to the routine, noncontrast lumbar MRI examinations, which included sagittal FSE T1-weighted (T1WI), T2-weighted (T2WI), short-tau inversion recovery (STIR), and axial FSE T2WI. The sequence was performed in over 500 patients over a 1-year period, without intravenous contrast, and with slice thickness and planes of section identical to the axial FSE T1WI and T2WI images. The sequence typically lasted about 4.5-6 min. Results: The use of T2FFE-SPIR enabled visualization of the ligamentum flavum in degenerative disease, and the exclusion of focal fatty lesions on FSE T2WI. Other benefits included: the identification of malignant foci, the uncommon detection of hemorrhage, and the elimination of spurious flow voids. Several brief examples are provided to demonstrate the utility of this technique. Conclusion: The addition of T2FFE-SPIR to routine, noncontrast protocols in outpatients could provide further confidence in the visualization of the ligamentum flavum in degenerative disease, and can exclude malignancy in T2-bright areas of focal fatty marrow. Larger studies would be helpful to evaluate the accuracy of this technique versus FSE techniques in depicting degenerative, malignant, or inflammatory

  17. Fat-Suppressed T2 Sequences for Routine 3.0-Tesla Lumbar Spine Magnetic Resonance Imaging: A Preliminary Report

    Energy Technology Data Exchange (ETDEWEB)

    McKinney, A. M.; Gadani, S.; Palmer, C. S.; Vidarsson, L. (Dept. of Radiology, Hennepin County and Univ. of Minnesota Medical Centers, Minneapolis, MN (United States))

    2008-09-15

    Background: Clear depiction of the ligamentum flavum on routine lumbar magnetic resonance imaging (MRI) is essential in accurately describing the extent of degenerative disease. In routine, noncontrast evaluations, focal fatty deposition or hemangiomas can be difficult to distinguish from malignant foci on fast spin-echo (FSE) T2-weighted images. Purpose: To describe the use of T2 fast field echo (T2FFE) in combination with spectral presaturation inversion recovery (SPIR) fat suppression for noncontrast, routine lumbar spine outpatient MR imaging at 3.0 Tesla (3T). Material and Methods: An axial gradient echo (GE) T2FFE sequence was combined with SPIR fat suppression (T2FFE-SPIR), via a 3T Philips Intera (Philips Medical Systems, Best, The Netherlands) scanner, and added to the routine, noncontrast lumbar MRI examinations, which included sagittal FSE T1-weighted (T1WI), T2-weighted (T2WI), short-tau inversion recovery (STIR), and axial FSE T2WI. The sequence was performed in over 500 patients over a 1-year period, without intravenous contrast, and with slice thickness and planes of section identical to the axial FSE T1WI and T2WI images. The sequence typically lasted about 4.5-6 min. Results: The use of T2FFE-SPIR enabled visualization of the ligamentum flavum in degenerative disease, and the exclusion of focal fatty lesions on FSE T2WI. Other benefits included: the identification of malignant foci, the uncommon detection of hemorrhage, and the elimination of spurious flow voids. Several brief examples are provided to demonstrate the utility of this technique. Conclusion: The addition of T2FFE-SPIR to routine, noncontrast protocols in outpatients could provide further confidence in the visualization of the ligamentum flavum in degenerative disease, and can exclude malignancy in T2-bright areas of focal fatty marrow. Larger studies would be helpful to evaluate the accuracy of this technique versus FSE techniques in depicting degenerative, malignant, or inflammatory

  18. Hepatocellular carcinoma with marginal superparamagnetic iron oxide uptake on T2*-weighted magnetic resonance imaging: Histopathologic correlation

    International Nuclear Information System (INIS)

    Ishigami, Kousei; Tajima, Tsuyoshi; Fujita, Nobuhiro; Nishie, Akihiro; Asayama, Yoshiki; Kakihara, Daisuke; Nakayama, Tomohiro; Okamoto, Daisuke; Taketomi, Akinobu; Shirabe, Ken; Honda, Hiroshi

    2011-01-01

    Purpose: To evaluate the characteristics of hepatocellular carcinomas (HCCs) with marginal superparamagnetic iron oxide (SPIO) uptake on T2*-weighted MRI. Materials and methods: The study group consisted of 73 patients with 83 surgically resected HCCs. Preoperative SPIO-enhanced MRI studies were retrospectively reviewed. Marginal SPIO uptake was considered positive if a rim-like or band-like low intensity area was present on SPIO-enhanced T2*-weighted images. The prevalence of marginal SPIO uptake was evaluated. Pathological specimens with hematoxylin and eosin staining and immunohistochemical staining of CD68 were reviewed in HCCs with marginal SPIO uptake and 33 HCCs without marginal SPIO uptake (control group). Results: Ten of 83 (12%) HCCs showed marginal SPIO uptake. All HCCs were hypervascular, and only one nodule showed a nodule-in-nodule appearance on imaging findings. The pathology specimens suggested possible causes of marginal SPIO uptake, including marginal macrophage infiltration in moderately or poorly differentiated HCC (n = 4), residual normal hepatic tissue at the marginal area of confluent multinodular or single nodular with extranodular growth type HCC (n = 3), and a well-differentiated HCC component in nodule-in-nodule type HCC (n = 3). Marginal macrophage infiltration was not seen in the control group. Conclusion: SPIO-enhanced MRI may be able to demonstrate marginal macrophage infiltration in HCC.

  19. The appearances of oesophageal carcinoma demonstrated on high-resolution, T2-weighted MRI, with histopathological correlation

    International Nuclear Information System (INIS)

    Riddell, A.M.; Allum, W.H.; Thompson, J.N.; Wotherspoon, A.C.; Richardson, C.; Brown, G.

    2007-01-01

    This paper describes the spectrum of imaging features of oesophageal adenocarcinoma seen using high-resolution T2-weighted (T2W) magnetic resonance imaging (MRI). Thirty-nine patients with biopsy-proven oesophageal adenocarcinoma were scanned using an external surface coil. A sagittal T2W sequence was used to localise the tumour and to plan axial images perpendicular to the tumour. Fast spin-echo (FSE) T2W axial sequence parameters were: TR/TE, 3,300-5,000 ms/120-80 ms; field of view (FOV) 225 mm, matrix 176 x 512(reconstructed) mm to 256 x 224 mm, giving an in-plane resolution of between 1.28 x 0.44 mm and 0.88 x 1.00 mm, with 3-mm slice thickness. Thirty-three patients underwent resection and the MR images were compared with the histological whole-mount sections. There were four T1, 12 T2, and 17 T3 tumours. The T2W high-resolution MRI sequences produced detailed images of the oesophageal wall and surrounding structures. Analysis of the imaging appearances for different tumour T stages enabled the development of imaging criteria for local staging of oesophageal cancer using high-resolution MRI. Our study illustrates the spectrum of appearances of oesophageal cancer on T2W high-resolution MRI, and using the criteria established in this study, demonstrates the potential of this technique as an alternative non-invasive method for local staging for oesophageal cancer. (orig.)

  20. T2-weighted signal intensity-selected volumetry for prediction of pathological complete response after preoperative chemoradiotherapy in locally advanced rectal cancer.

    Science.gov (United States)

    Kim, Sungwon; Han, Kyunghwa; Seo, Nieun; Kim, Hye Jin; Kim, Myeong-Jin; Koom, Woong Sub; Ahn, Joong Bae; Lim, Joon Seok

    2018-06-01

    To evaluate the diagnostic value of signal intensity (SI)-selected volumetry findings in T2-weighted magnetic resonance imaging (MRI) as a potential biomarker for predicting pathological complete response (pCR) to preoperative chemoradiotherapy (CRT) in patients with rectal cancer. Forty consecutive patients with pCR after preoperative CRT were compared with 80 age- and sex-matched non-pCR patients in a case-control study. SI-selected tumor volume was measured on post-CRT T2-weighted MRI, which included voxels of the treated tumor exceeding the SI (obturator internus muscle SI + [ischiorectal fossa fat SI - obturator internus muscle SI] × 0.2). Three blinded readers independently rated five-point pCR confidence scores and compared the diagnostic outcome with SI-selected volumetry findings. The SI-selected volumetry protocol was validated in 30 additional rectal cancer patients. The area under the receiver-operating characteristic curve (AUC) of SI-selected volumetry for pCR prediction was 0.831, with an optimal cutoff value of 649.6 mm 3 (sensitivity 0.850, specificity 0.725). The AUC of the SI-selected tumor volume was significantly greater than the pooled AUC of readers (0.707, p volumetry in post-CRT T2-weighted MRI can help predict pCR after preoperative CRT in patients with rectal cancer. • Fibrosis and viable tumor MRI signal intensities (SIs) are difficult to distinguish. • T2 SI-selected volumetry yields high diagnostic performance for assessing pathological complete response. • T2 SI-selected volumetry is significantly more accurate than readers and non-SI-selected volumetry. • Post-chemoradiation therapy T2-weighted MRI SI-selected volumetry facilitates prediction of pathological complete response.

  1. Gaining insight into the T _2^*-T2 relationship in surface NMR free-induction decay measurements

    Science.gov (United States)

    Grombacher, Denys; Auken, Esben

    2018-05-01

    One of the primary shortcomings of the surface nuclear magnetic resonance (NMR) free-induction decay (FID) measurement is the uncertainty surrounding which mechanism controls the signal's time dependence. Ideally, the FID-estimated relaxation time T_2^* that describes the signal's decay carries an intimate link to the geometry of the pore space. In this limit the parameter T_2^* is closely linked to a related parameter T2, which is more closely linked to pore-geometry. If T_2^* ˜eq {T_2} the FID can provide valuable insight into relative pore-size and can be used to make quantitative permeability estimates. However, given only FID measurements it is difficult to determine whether T_2^* is linked to pore geometry or whether it has been strongly influenced by background magnetic field inhomogeneity. If the link between an observed T_2^* and the underlying T2 could be further constrained the utility of the standard surface NMR FID measurement would be greatly improved. We hypothesize that an approach employing an updated surface NMR forward model that solves the full Bloch equations with appropriately weighted relaxation terms can be used to help constrain the T_2^*-T2 relationship. Weighting the relaxation terms requires estimating the poorly constrained parameters T2 and T1; to deal with this uncertainty we propose to conduct a parameter search involving multiple inversions that employ a suite of forward models each describing a distinct but plausible T_2^*-T2 relationship. We hypothesize that forward models given poor T2 estimates will produce poor data fits when using the complex-inversion, while forward models given reliable T2 estimates will produce satisfactory data fits. By examining the data fits produced by the suite of plausible forward models, the likely T_2^*-T2 can be constrained by identifying the range of T2 estimates that produce reliable data fits. Synthetic and field results are presented to investigate the feasibility of the proposed technique.

  2. Physiological noise in murine solid tumours using T2*-weighted gradient-echo imaging: a marker of tumour acute hypoxia?

    International Nuclear Information System (INIS)

    Baudelet, Christine; Ansiaux, Reginald; Jordan, Benedicte F; Havaux, Xavier; Macq, Benoit; Gallez, Bernard

    2004-01-01

    T2*-weighted gradient-echo magnetic resonance imaging (T2*-weighted GRE MRI) was used to investigate spontaneous fluctuations in tumour vasculature non-invasively. FSa fibrosarcomas, implanted intramuscularly (i.m.) in the legs of mice, were imaged at 4.7 T, over a 30 min or 1 h sampling period. On a voxel-by-voxel basis, time courses of signal intensity were analysed using a power spectrum density (PSD) analysis to isolate voxels for which signal changes did not originate from Gaussian white noise or linear drift. Under baseline conditions, the tumours exhibited spontaneous signal fluctuations showing spatial and temporal heterogeneity over the tumour. Statistically significant fluctuations occurred at frequencies ranging from 1 cycle/3 min to 1 cycle/h. The fluctuations were independent of the scanner instabilities. Two categories of signal fluctuations were reported: (i) true fluctuations (TFV), i.e., sequential signal increase and decrease, and (ii) profound drop in signal intensity with no apparent signal recovery (SDV). No temporal correlation between tumour and contralateral muscle fluctuations was observed. Furthermore, treatments aimed at decreasing perfusion-limited hypoxia, such as carbogen combined with nicotinamide and flunarizine, decreased the incidence of tumour T2*-weighted GRE fluctuations. We also tracked dynamic changes in T2* using multiple GRE imaging. Fluctuations of T2* were observed; however, fluctuation maps using PSD analysis could not be generated reliably. An echo-time dependency of the signal fluctuations was observed, which is typical to physiological noise. Finally, at the end of T2*-weighted GRE MRI acquisition, a dynamic contrast-enhanced MRI was performed to characterize the microenvironment in which tumour signal fluctuations occurred in terms of vessel functionality, vascularity and microvascular permeability. Our data showed that TFV were predominantly located in regions with functional vessels, whereas SDV occurred in regions

  3. T2-weighted fast spin-echo MR imaging of the pelvis

    International Nuclear Information System (INIS)

    Francis, I.R.; Steiner, R.M.; Herfkens, R.J.; Jain, K.; Glover, G.H.

    1991-01-01

    A fast Se (FSE) sequence capable of acquiring SE images with a wide range of TRs and TEs in short imaging times has been recently introduced. I this paper, the authors evaluated the value of this technique compared with standard T2-weighted SE imaging. Twenty-five patients were evaluated with T2-weighted SE and FSE images on a 1.5-T GE Signa imager. Imaging times ranged from 3 to 5 minutes for the FSE acquisition and from 12 to 15 minutes for the SE images. Three observers performed a comparison by using a 10-point scale for organ definition and lesion conspicuity, with differences settled by consensus reading. Pelvic organ definition was superior and pelvic tumors and free fluid were also more conspicuous on FSE images. In 2/25 patients ringing artifacts were present

  4. Fully convolutional networks (FCNs)-based segmentation method for colorectal tumors on T2-weighted magnetic resonance images.

    Science.gov (United States)

    Jian, Junming; Xiong, Fei; Xia, Wei; Zhang, Rui; Gu, Jinhui; Wu, Xiaodong; Meng, Xiaochun; Gao, Xin

    2018-06-01

    Segmentation of colorectal tumors is the basis of preoperative prediction, staging, and therapeutic response evaluation. Due to the blurred boundary between lesions and normal colorectal tissue, it is hard to realize accurate segmentation. Routinely manual or semi-manual segmentation methods are extremely tedious, time-consuming, and highly operator-dependent. In the framework of FCNs, a segmentation method for colorectal tumor was presented. Normalization was applied to reduce the differences among images. Borrowing from transfer learning, VGG-16 was employed to extract features from normalized images. We conducted five side-output blocks from the last convolutional layer of each block of VGG-16 along the network, these side-output blocks can deep dive multiscale features, and produced corresponding predictions. Finally, all of the predictions from side-output blocks were fused to determine the final boundaries of the tumors. A quantitative comparison of 2772 colorectal tumor manual segmentation results from T2-weighted magnetic resonance images shows that the average Dice similarity coefficient, positive predictive value, specificity, sensitivity, Hammoude distance, and Hausdorff distance were 83.56, 82.67, 96.75, 87.85%, 0.2694, and 8.20, respectively. The proposed method is superior to U-net in colorectal tumor segmentation (P colorectal tumor segmentation (P > 0.05). The results indicate that the introduction of FCNs contributed to accurate segmentation of colorectal tumors. This method has the potential to replace the present time-consuming and nonreproducible manual segmentation method.

  5. Magnetic resonance enteroclysis in patients with Crohn's disease: fat saturated T2-weighted sequences for evaluation of inflammatory activity.

    Science.gov (United States)

    Grieser, Christian; Denecke, Timm; Steffen, Ingo G; Werner, Scarlett; Kröncke, Thomas; Guckelberger, Olaf; Pape, Ulrich-Frank; Meier, Johannes; Thiel, Regina; Kivelitz, Dietmar; Sturm, Andreas; Hamm, Bernd; Röttgen, Rainer

    2012-04-01

    To evaluate fat saturated (fs) T2-weighted (w) fast relaxation fast spin echo (FRFSE)-sequences compared to the standard protocol with contrast agent for the evaluation of inflammatory activity in patients with Crohn's Disease (CD). Fourty-eight patients (male, 17; female, 33; mean age, 37 years) with suspicion of inflammatory activity in proven CD who underwent MR enteroclysis (MRE) at 1.5T (GE Healthcare) were retrospectively included. Two blinded radiologists analyzed MRE images for presence and extent of CD lesions and degree of local inflammation for fsT2-w FRFSE and contrast enhanced T1-w images (T2-activity; T1-activity; score, 1-4) in consensus. Furthermore, mural signal intensity (SI) ratios (T2-ratio; T1-ratio) were recorded. Patient based MRE findings were correlated with endoscopic (45 patients), surgical (6 patients), histopathological, and clinical data (CDAI) as a surrogate reference standard. In total, 24 of 48 eligible patients presented with acute inflammatory activity with 123 affected bowel segments. ROC analysis of the total inflammatory score presented an AUC of 0.93 (pT2-activity (T1-activity, AUC 0.63; p=0.019). ROC analysis revealed an AUC of 0.76 (pT2-ratio (T1-ratio, AUC 0.51; p=0.93). General linear regression model revealed T2-activity (p=0.001) and age (p=0.024) as predictive factors of acute bowel inflammation. T2-w FRFSE-sequences can depict CD lesions and help to assess the inflammation activity, even with improved accuracy as compared to contrast-enhanced T1-w sequences. Copyright © 2011 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.

  6. A neurotological study of patients with pontine hyperintense lesions on T2 weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Toru; Tominaga, Satoru; Yukimasa, Akiko; Oku, Masaya; Sakagami, Masafumi [Hyogo Coll. of Medicine, Nishinomiya (Japan)

    2002-03-01

    Pontine hyperintense lesions seen on T2-weighted MRI were thought to be related to disequilibrium. Some of these lesions have a low signal on T1-weighted imaging, while others have an iso-signal. The purpose of this study was to clarify the relationship between neurological findings and pontine lesions detected by MRI. The subjects were 11 patients (6 males, 5 females; age range: 30 to 83 years [mean: 64.1 years]) with pontine hyperintense lesions identified on T2-weighted MRI. We compared the clinical signs and the MRI findings. Six of the patients had low-intensity areas on T1-weighted images, and the other 5 had iso-intensity areas. Six patients complained of vertigo, and 5 complained of dizziness. Eight complained of positionaly evoked disequilibrium. Positional nystagmus was seen in 4 patients. In 9 patients, abnormalities were found on the ENG test, including the saccadic eye movement test, ETT, and OKP. Numbness on the lips occurred in 2 patients, and cerebellar signs were present in 4. None of the patients had facial paralysis. Disequilibrium originating in the central nervous system was suggested in 10 patients. Clinical examinations revealed similar findings in patients with a low signal on T1-weighted MRI and those with an iso-signal. Our results indicate that pontine lesions identified by T2-weighted MRI cause vertigo or dizziness, and, in most cases, these lesions cause abnormal neurological or neurological abnormalities. (author)

  7. A neurotological study of patients with pontine hyperintense lesions on T2 weighted MRI

    International Nuclear Information System (INIS)

    Seo, Toru; Tominaga, Satoru; Yukimasa, Akiko; Oku, Masaya; Sakagami, Masafumi

    2002-01-01

    Pontine hyperintense lesions seen on T2-weighted MRI were thought to be related to disequilibrium. Some of these lesions have a low signal on T1-weighted imaging, while others have an iso-signal. The purpose of this study was to clarify the relationship between neurological findings and pontine lesions detected by MRI. The subjects were 11 patients (6 males, 5 females; age range: 30 to 83 years [mean: 64.1 years]) with pontine hyperintense lesions identified on T2-weighted MRI. We compared the clinical signs and the MRI findings. Six of the patients had low-intensity areas on T1-weighted images, and the other 5 had iso-intensity areas. Six patients complained of vertigo, and 5 complained of dizziness. Eight complained of positionaly evoked disequilibrium. Positional nystagmus was seen in 4 patients. In 9 patients, abnormalities were found on the ENG test, including the saccadic eye movement test, ETT, and OKP. Numbness on the lips occurred in 2 patients, and cerebellar signs were present in 4. None of the patients had facial paralysis. Disequilibrium originating in the central nervous system was suggested in 10 patients. Clinical examinations revealed similar findings in patients with a low signal on T1-weighted MRI and those with an iso-signal. Our results indicate that pontine lesions identified by T2-weighted MRI cause vertigo or dizziness, and, in most cases, these lesions cause abnormal neurological or neurological abnormalities. (author)

  8. Added value of gadoxetic acid-enhanced T1-weighted magnetic resonance cholangiography for the diagnosis of post-transplant biliary complications

    Energy Technology Data Exchange (ETDEWEB)

    Kinner, Sonja [University of Wisconsin School of Medicine and Public Health, Department of Radiology, Madison, WI (United States); University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Schubert, Tilman B. [University of Wisconsin School of Medicine and Public Health, Department of Radiology, Madison, WI (United States); Basel University Hospital, Clinic of Radiology and Nuclear Medicine, Basel (Switzerland); Said, Adnan [University of Wisconsin-Madison, Department of Medicine, Madison, WI (United States); Mezrich, Joshua D. [University of Wisconsin-Madison, Department of Surgery, Madison, WI (United States); Reeder, Scott B. [University of Wisconsin School of Medicine and Public Health, Department of Radiology, Madison, WI (United States); University of Wisconsin-Madison, Department of Medicine, Madison, WI (United States); University of Wisconsin-Madison, Department of Biomedical Engineering, Madison, WI (United States); University of Wisconsin-Madison, Department of Medical Physics, Madison, WI (United States); University of Wisconsin-Madison, Department of Emergency Medicine, Madison, WI (United States)

    2017-10-15

    Biliary complications after liver transplantation (LT) are common. This study aimed to ascertain the value of gadoxetic acid-enhanced T1-weighted (T1w) magnetic resonance cholangiography (MRC) to evaluate anastomotic strictures (AS), non-anastomotic strictures (NAS) and biliary casts (BC). Sixty liver-transplanted patients with suspicion of biliary complications and T2w-MRCP and T1w-MRC followed by endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC) were analysed. Two readers reviewed the MRCs and rated image quality (IQ) and likelihood for AS/NAS/BC on Likert scales. Sensitivity, specificity and predictive values were calculated, ROC curve analysis performed, and inter-reader variability assessed. The subjective added value of T1w-MRC was rated. IQ was high for all sequences without significant differences (2.83-2.88). In 39 patients ERCP/PTC detected a complication. Sensitivity and specificity for AS were 64-96 using T2w-MRCP, increasing to 79-100 using all sequences. Use of all sequences increased the sensitivity of detecting NAS/BC from 72-92% to 88-100% and 67-89% to 72-94%, respectively. Kappa values were substantial (0.45-0.62). T1w-MRC was found to be helpful in 75-83.3%. Combining T1w-MRC and T2w-MRCP increased sensitivity and specificity and diagnostic confidence in patients after LT with suspected biliary complications. T1w-MRC is a valuable tool for evaluating post-transplant biliary complications. (orig.)

  9. Basic evaluation of the new pulse sequence for simultaneous acquisition of T1- and T2-weighted images

    International Nuclear Information System (INIS)

    Kurose, Atsunari; Takahashi, Tohru; Ohishi, Tae; Ishikawa, Akihiro

    2006-01-01

    A novel pulse sequence that enables simultaneous acquisition of T1-weighted (T1W) and T2-weighted (T2W) images is presented. In this new technique, the inversion recovery (IR) pulse of conventional fast inversion recovery (Fast IR) is replaced with a pulse train that consists of a fast spin echo (FSE) and 180(y)+90(x) for driven inversion (DI). By using a shorter T1 and independent k-space ordering, the first part of the sequence provides T2W images and the second part provides T1W images, thereby enabling simultaneous acquisition in a single scan time comparable to that of Fast IR. Signal simulation also was conducted, and this was compared with conventional scanning techniques using normal volunteers. In the human studies, both T1W and T2W images showed the same image quality as conventional images, suggesting the potential for this technique to replace the combination of Fast IR and T2W FSE for scan-time reduction. (author)

  10. Carotid plaque signal differences among four kinds of T1-weighted magnetic resonance imaging techniques: A histopathological correlation study

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Ayumi; Narumi, Shinsuke; Ohba, Hideki; Yamaguchi, Mao; Terayama, Yasuo [Iwate Medical University, Department of Neurology and Gerontology, Morioka (Japan); Sasaki, Makoto; Kudo, Kohsuke [Iwate Medical University, Institute for Biomedical Sciences, Morioka (Japan); Ogasawara, Kuniaki; Kobayashi, Masakazu [Iwate Medical University, Department of Neurosurgery, Morioka (Japan); Hitomi, Jiro [Iwate Medical University, Department of Anatomy, Morioka (Japan)

    2012-11-15

    Several magnetic resonance (MR) imaging techniques are used to examine atherosclerotic plaque of carotid arteries; however, the best technique for visualizing intraplaque characteristics has yet to be determined. Here, we directly compared four kinds of T1-weighted (T1W) imaging techniques with pathological findings in patients with carotid stenosis. A total of 31 patients who were candidates for carotid endarterectomy were prospectively examined using a 1.5-T MRI scanner, which produced four kinds of T1W images, including non-gated spin echo (SE), cardiac-gated black-blood (BB) fast-SE (FSE), magnetization-prepared rapid acquisition with gradient echo (MPRAGE), and source image of three-dimensional time-of-flight MR angiography (SI-MRA). The signal intensity of the carotid plaque was manually measured, and the contrast ratio (CR) against the adjacent muscle was calculated. CRs from the four imaging techniques were compared to each other and correlated with histopathological specimens. CRs of the carotid plaques mainly containing fibrous tissue, lipid/necrosis, and hemorrhage were significantly different with little overlaps (range: 0.92-1.15, 1.22-1.52, and 1.55-2.30, respectively) on non-gated SE. However, BB-FSE showed remarkable overlaps among the three groups (0.89-1.10, 1.07-1.23, and 1.01-1.42, respectively). MPRAGE could discriminate fibrous plaques from hemorrhagic plaques but not from lipid/necrosis-rich plaques: (0.77-1.07, 1.45-2.43, and 0.85-1.42, respectively). SI-MRA showed the same tendencies (1.01-1.39, 1.45-2.57, and 1.12-1.39, respectively). Among T1W MR imaging techniques, non-gated SE images can more accurately characterize intraplaque components in patients who underwent CEA when compared with cardiac-gated BB-FSE, MPRAGE, and SI-MRA images. (orig.)

  11. Coupling between magnetic, dielectric properties and crystal structure in MnT2O4 (T = V, Cr, Mn)

    International Nuclear Information System (INIS)

    Suzuki, T; Adachi, K; Katsufuji, T

    2006-01-01

    We measured the temperature dependence of dielectric constant and striction for spinel MnT 2 O 4 (T = V, Cr, Mn) under magnetic field. We found critical changes of the dielectric constant and striction with ferrimagnetic ordering as well as applied magnetic field in MnV 2 O 4 and Mn 3 O 4 , which have orbital degree of freedom in the T 3+ ion. This result indicates the importance of the orbital degree of freedom for the coupling between dielectric, magnetic properties and crystal structure in these spinel compounds

  12. Carbon Nano-Allotrope/Magnetic Nanoparticle Hybrid Nanomaterials as T2 Contrast Agents for Magnetic Resonance Imaging Applications

    Directory of Open Access Journals (Sweden)

    Yunxiang Gao

    2018-02-01

    Full Text Available Magnetic resonance imaging (MRI is the most powerful tool for deep penetration and high-quality 3D imaging of tissues with anatomical details. However, the sensitivity of the MRI technique is not as good as that of the radioactive or optical imaging methods. Carbon-based nanomaterials have attracted significant attention in biomaterial research in recent decades due to their unique physical properties, versatile functionalization chemistry, as well as excellent biological compatibility. Researchers have employed various carbon nano-allotropes to develop hybrid MRI contrast agents for improved sensitivity. This review summarizes the new research progresses in carbon-based hybrid MRI contrast agents, especially those reported in the past five years. The review will only focus on T2-weighted MRI agents and will be categorized by the different carbon allotrope types and magnetic components. Considering the strong trend in recent bio-nanotechnology research towards multifunctional diagnosis and therapy, carbon-based MRI contrast agents integrated with other imaging modalities or therapeutic functions are also covered.

  13. Occipital lobe seizures and subcortical T2 and T2* hypointensity associated with nonketotic hyperglycemia: a case report.

    Science.gov (United States)

    Sasaki, Fuyuko; Kawajiri, Sumihiro; Nakajima, Sho; Yamaguchi, Ai; Tomizawa, Yuji; Noda, Kazuyuki; Hattori, Nobutaka; Okuma, Yasuyuki

    2016-08-12

    Nonketotic hyperglycemia often causes seizures. Recently, seizures associated with nonketotic hyperglycemia have been found to be associated with subcortical T2 hypointensity on magnetic resonance imaging, especially in the occipital lobes. However, the mechanism remains unclear, although iron accumulation is suggested. We present a case of occipital lobe seizures associated with nonketotic hyperglycemia supporting the hypothesis that the mechanism of subcortical T2 hypointensity is iron accumulation using gradient-echo T2*-weighted magnetic resonance imaging. A 65-year-old Japanese man complained of intermittent pastel-colored flashing lights. On neurological examination, he also had lower right-side quadrant hemianopia. No other abnormal neurological findings were found. On laboratory analysis, his blood glucose level was 370 mg/dL, HbA1c was 11.4 %, and serum osmolarity was 326 mOsm/L. No ketones were detected in urine. A magnetic resonance imaging scan of his head showed subcortical T2 and T2* hypointensity in his left occipital lobe. Single-photon emission computed tomography with I123-N-isopropyl-iodoamphetamine revealed hyperperfusion in the left dominant occipital lobe. These magnetic resonance imaging abnormalities resolved during clinical recovery and treatment to control his blood sugar level. Therefore, a diagnosis of occipital lobe seizures associated with nonketotic hyperglycemia was made. To the best of our knowledge, this is the first case of occipital lobe seizures associated with nonketotic hyperglycemia supporting the role of iron accumulation as a mechanism for subcortical T2 hypointensity using T2*-magnetic resonance imaging.

  14. “Hot cross bun” sign in multiple system atrophy with predominant cerebellar ataxia: A comparison between proton density-weighted imaging and T2-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kasahara, Seiko, E-mail: nuun077@kuhp.kyoto-u.ac.jp [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan); Miki, Yukio, E-mail: yukio.miki@med.osaka-cu.ac.jp [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan); Department of Radiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545–8585 (Japan); Kanagaki, Mitsunori, E-mail: mitsuk@kuhp.kyoto-u.ac.jp [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan); Kondo, Takayuki, E-mail: kondotak@kuhp.kyoto-u.ac.jp [Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan); Yamamoto, Akira, E-mail: yakira@kuhp.kyoto-u.ac.jp [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan); Morimoto, Emiko, E-mail: foresta@kuhp.kyoto-u.ac.jp [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan); Okada, Tomohisa, E-mail: tomokada@kuhp.kyoto-u.ac.jp [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan); Ito, Hidefumi, E-mail: itohid@kuhp.kyoto-u.ac.jp [Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan); Takahashi, Ryosuke, E-mail: ryosuket@kuhp.kyoto-u.ac.jp [Department of Neurology, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507 (Japan); and others

    2012-10-15

    Objective: To investigate whether proton density-weighted imaging can detect the “hot cross bun” sign in the pons in multiple system atrophy with predominant cerebellar ataxia significantly better than T2-weighted imaging at 3 T. Methods: Sixteen consecutive patients with multiple system atrophy with predominant cerebellar ataxia according to the Consensus Criteria were reviewed. Axial unenhanced proton density-weighted imaging and T2-weighted imaging were obtained using a dual-echo fast spin-echo sequence at 3 T. Two neuroradiologists independently evaluated visualisation of the abnormal pontine signal using a 4-point visual grade from Grade 0 (no “hot cross bun” sign) to Grade 3 (prominent “hot cross bun” sign on two or more sequential slices). Differences in grade between proton density-weighted imaging and T2-weighted imaging were statistically analysed using the Wilcoxon signed-rank test. Results: In 11 patients (69%), a higher grade was given for proton density-weighted imaging than T2-weighted imaging. In 1 patient (6%), grades were the same (Grade 3) on both images. In the remaining 4 patients (25%), signal abnormalities were not detected on either image (Grade 0). The “hot cross bun” sign was thus observed significantly better on proton density-weighted imaging than on T2-weighted imaging (P = 0.001). Conclusions: The “hot cross bun” sign considered diagnostic for multiple system atrophy with predominant cerebellar ataxia is significantly better visualised on proton density-weighted imaging than on T2-weighted imaging at 3 T.

  15. High intensity focused ultrasound treatment of adenomyosis: The relationship between the features of magnetic resonance imaging on T2 weighted images and the therapeutic efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Chunmei [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, Chongqing Haifu Hospital, College of Biomedical Engineering, Chongqing Medical University, Chongqing (China); Setzen, Raymond [Department of Obstetrics and Gynecology, Chris Hani Baragwanath Academic Hospital, Johannesburg (South Africa); Liu, Zhongqiong; Liu, Yunchang [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, Chongqing Haifu Hospital, College of Biomedical Engineering, Chongqing Medical University, Chongqing (China); Xie, Bin [Department of Ultrasound, Huanggang Central Hospital, Huanggang City, Hubei 438000 (China); Aili, Aixingzi, E-mail: 1819483078@qq.com [Shanghai First Maternity and Infant Health Hospital, Shanghai (China); Zhang, Lian, E-mail: lianwzhang@yahoo.com [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, Chongqing Haifu Hospital, College of Biomedical Engineering, Chongqing Medical University, Chongqing (China)

    2017-04-15

    Objectives: To investigate the relationship between the features of magnetic resonance imaging (MRI) on T2 weighted images (T2WI) and the therapeutic efficacy of high intensity focused ultrasound (HIFU) on adenomyosis. Materials and methods: From January 2011 to November 2015, four hundred and twenty-eight patients with symptomatic adenomyosis were treated with HIFU. Based on the signal intensity and the number of hyperintense foci in the adenomyotic lesions on T2WI, the patients were classified into groups. The day after HIFU ablation patients underwent contrast-enhanced MRI and a comparison was made of non-perfused volume (NPV) ratio, energy efficiency factor (EEF), treatment time, sonication time, and adverse effects. Results: No significant difference in terms of HIFU treatment settings and results was observed between the group of patients with hypointense adenomyotic lesions and the group with isointense adenomyotic lesions (P > 0.05). However, the sonication time and EEF were significantly higher in the group with multiple hyperintense foci compared to the group with few hyperintense foci. The NPV ratio achieved in the lesions with multiple hyperintenese foci was significantly lower than that in the lesions with few hyperintense foci (P < 0.05). No significant difference was observed in the rate of adverse effects between the two groups. Conclusions: Based on our results, the response of the adenomyotic lesions to HIFU treatment is not related to the signal intensity of adenomyotic lesions on T2WI. However, the number of the high signal intensity foci in the adenomyotic lesions on T2WI can be considered as a predictive factor to help select patients for HIFU treatment.

  16. High intensity focused ultrasound treatment of adenomyosis: The relationship between the features of magnetic resonance imaging on T2 weighted images and the therapeutic efficacy

    International Nuclear Information System (INIS)

    Gong, Chunmei; Setzen, Raymond; Liu, Zhongqiong; Liu, Yunchang; Xie, Bin; Aili, Aixingzi; Zhang, Lian

    2017-01-01

    Objectives: To investigate the relationship between the features of magnetic resonance imaging (MRI) on T2 weighted images (T2WI) and the therapeutic efficacy of high intensity focused ultrasound (HIFU) on adenomyosis. Materials and methods: From January 2011 to November 2015, four hundred and twenty-eight patients with symptomatic adenomyosis were treated with HIFU. Based on the signal intensity and the number of hyperintense foci in the adenomyotic lesions on T2WI, the patients were classified into groups. The day after HIFU ablation patients underwent contrast-enhanced MRI and a comparison was made of non-perfused volume (NPV) ratio, energy efficiency factor (EEF), treatment time, sonication time, and adverse effects. Results: No significant difference in terms of HIFU treatment settings and results was observed between the group of patients with hypointense adenomyotic lesions and the group with isointense adenomyotic lesions (P > 0.05). However, the sonication time and EEF were significantly higher in the group with multiple hyperintense foci compared to the group with few hyperintense foci. The NPV ratio achieved in the lesions with multiple hyperintenese foci was significantly lower than that in the lesions with few hyperintense foci (P < 0.05). No significant difference was observed in the rate of adverse effects between the two groups. Conclusions: Based on our results, the response of the adenomyotic lesions to HIFU treatment is not related to the signal intensity of adenomyotic lesions on T2WI. However, the number of the high signal intensity foci in the adenomyotic lesions on T2WI can be considered as a predictive factor to help select patients for HIFU treatment.

  17. Focal liver lesions segmentation and classification in nonenhanced T2-weighted MRI.

    Science.gov (United States)

    Gatos, Ilias; Tsantis, Stavros; Karamesini, Maria; Spiliopoulos, Stavros; Karnabatidis, Dimitris; Hazle, John D; Kagadis, George C

    2017-07-01

    To automatically segment and classify focal liver lesions (FLLs) on nonenhanced T2-weighted magnetic resonance imaging (MRI) scans using a computer-aided diagnosis (CAD) algorithm. 71 FLLs (30 benign lesions, 19 hepatocellular carcinomas, and 22 metastases) on T2-weighted MRI scans were delineated by the proposed CAD scheme. The FLL segmentation procedure involved wavelet multiscale analysis to extract accurate edge information and mean intensity values for consecutive edges computed using horizontal and vertical analysis that were fed into the subsequent fuzzy C-means algorithm for final FLL border extraction. Texture information for each extracted lesion was derived using 42 first- and second-order textural features from grayscale value histogram, co-occurrence, and run-length matrices. Twelve morphological features were also extracted to capture any shape differentiation between classes. Feature selection was performed with stepwise multilinear regression analysis that led to a reduced feature subset. A multiclass Probabilistic Neural Network (PNN) classifier was then designed and used for lesion classification. PNN model evaluation was performed using the leave-one-out (LOO) method and receiver operating characteristic (ROC) curve analysis. The mean overlap between the automatically segmented FLLs and the manual segmentations performed by radiologists was 0.91 ± 0.12. The highest classification accuracies in the PNN model for the benign, hepatocellular carcinoma, and metastatic FLLs were 94.1%, 91.4%, and 94.1%, respectively, with sensitivity/specificity values of 90%/97.3%, 89.5%/92.2%, and 90.9%/95.6% respectively. The overall classification accuracy for the proposed system was 90.1%. Our diagnostic system using sophisticated FLL segmentation and classification algorithms is a powerful tool for routine clinical MRI-based liver evaluation and can be a supplement to contrast-enhanced MRI to prevent unnecessary invasive procedures. © 2017 American

  18. Analysis of high signal intensities of nontumorous conditions of corpus callosum on magnetic resonance T2-weighted images

    International Nuclear Information System (INIS)

    Kang, Moo Song; Kim, Chul Min; Chung, Chun Phil

    1995-01-01

    To evaluate high signal intensity of nontumorous conditions of corpus callosum on T2-weighted MR images. Forty nine patients with nontumorous high signal intensities involving corpus callosum on sagittal T2-weighted image were retrospectively analyzed. Nontumorous condition of corpus callosum were diffuse axonal injury (DAI, 19 cases), cerebral infarctions (16 cases), multiple sclerosis (MS, 5 cases), Wilson's disease (2 cases) and hydrocephalus (7 cases) that were diagnosed by clinical and MR findings. Numbers, configuration, involved thickness and sites of high signal intensities of corpus callosum were analyzed. DAI and infarctions showed either single or multiple lesions. MS and hydrocephalus showed multiple lesions, but Wilson's diseases showed single lesion. In DAI, infarctions and MS the lesions involved any part of corpus callosum, splenium in Wilson's disease, and all parts of corpus callosum in hydrocephalus. Wilson's disease showed only partial thickness involvement, and others involved partial or full thickness of corpus callosum. Configuration of high signal intensity was linear in most cases of hydrocephalus, and oval in Wilson's disease, and oval and confluent in MS, and variable in DAI and infarctions. High signal intensities of nontumorous conditions of corpus callosum revealed variable findings, and therefore, analysis of nontumorous high signal intensities of corpus callosum is not made by only MR findings but by conjuction with clinical aspects

  19. Evaluation of T2-weighted versus short-tau inversion recovery sagittal sequences in the identification and localization of canine intervertebral disc extrusion with low-field magnetic resonance imaging.

    Science.gov (United States)

    Housley, Daniel; Caine, Abby; Cherubini, Giunio; Taeymans, Olivier

    2017-07-01

    Sagittal T2-weighted sequences (T2-SAG) are the foundation of spinal protocols when screening for the presence of intervertebral disc extrusion. We often utilize sagittal short-tau inversion recovery sequences (STIR-SAG) as an adjunctive screening series, and experience suggests that this combined approach provides superior detection rates. We hypothesized that STIR-SAG would provide higher sensitivity than T2-SAG in the identification and localization of intervertebral disc extrusion. We further hypothesized that the parallel evaluation of paired T2-SAG and STIR-SAG series would provide a higher sensitivity than could be achieved with either independent sagittal series when viewed in isolation. This retrospective diagnostic accuracy study blindly reviewed T2-SAG and STIR-SAG sequences from dogs (n = 110) with surgically confirmed intervertebral disc extrusion. A consensus between two radiologists found no significant difference in sensitivity between T2-SAG and STIR-SAG during the identification of intervertebral disc extrusion (T2-SAG: 92.7%, STIR-SAG: 94.5%, P = 0.752). Nevertheless, STIR-SAG accurately identified intervertebral disc extrusion in 66.7% of cases where the evaluation of T2-SAG in isolation had provided a false negative diagnosis. Additionally, one radiologist found that the parallel evaluation of paired T2-SAG and STIR-SAG series provided a significantly higher sensitivity than T2-SAG in isolation, during the identification of intervertebral disc extrusion (T2-SAG: 78.2%, paired T2-SAG, and STIR-SAG: 90.9%, P = 0.017). A similar nonsignificant trend was observed when the consensus of both radiologists was taken into consideration (T2-SAG: 92.7%, paired T2-SAG, and STIR-SAG = 97.3%, P = 0.392). We therefore conclude that STIR-SAG is capable of identifying intervertebral disc extrusion that is inconspicuous in T2-SAG, and that STIR-SAG should be considered a useful adjunctive sequence during preliminary sagittal screening for intervertebral disc

  20. A method for quantifying intervertebral disc signal intensity on T2-weighted imaging

    International Nuclear Information System (INIS)

    Nagashima, Masaki; Abe, Hitoshi; Amaya, Kenji; Matsumoto, Hideo; Yanaihara, Hisashi; Nishiwaki, Yuji; Toyama, Yoshiaki; Matsumoto, Morio

    2012-01-01

    Background Quantification of intervertebral disc degeneration based on intensity of the nucleus pulposus in magnetic resonance imaging (MRI) often uses the mean intensity of the region of interest (ROI) within the nucleus pulposus. However, the location and size of ROI have varied in different reports, and none of the reported methods can be considered fully objective. Purpose To develop a more objective method of establishing ROIs for quantitative evaluation of signal intensity in the nucleus pulposus using T2-weighted MRI. Material and Methods A 1.5-T scanner was used to obtain T2-weighted mid-sagittal images. A total of 288 intervertebral discs from 48 patients (25 men, 23 women) were analyzed. Mean age was 47.4 years (range, 17-69 years). All discs were classified into five grades according to Pfirrmann et al. Discs in grades I and II were defined as bright discs, and discs in grades IV and V were defined as dark discs. Eight candidate methods of ROI determination were devised. The method offering the highest degree of discrimination between bright and dark discs was investigated among these eight methods. Results The method with the greatest degree of discrimination was as follows. The quadrangle formed by anterior and posterior edges of the upper and lower end plates in contact with the intervertebral disc to be measured was defined as the intervertebral area. A shape similar to the intervertebral area but with one-quarter the area was drawn. The geometrical center of the shape was matched to the center of intensity, and this shape was then used as the ROI. Satisfactory validity and reproducibility were obtained using this method. Conclusion The present method offers adequate discrimination and could be useful for longitudinal tracking of intervertebral disc degeneration with sufficient reproducibility

  1. A method for quantifying intervertebral disc signal intensity on T2-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nagashima, Masaki [Dept. of Orthopaedic Surgery, Keio Univ. School of Medicine, Tokyo (Japan); Dept. of Orthopaedic Surgery, Kitasato Univ. Kitasato Inst. Hospital, Tokyo (Japan); Abe, Hitoshi [Dept. of Orthopaedic Surgery, Kitasato Univ. Kitasato Inst. Hospital, Tokyo (Japan)], E-mail: hit-abe@insti.kitasato-u.ac.jp; Amaya, Kenji [Graduate School of Information Science and Engineering, Tokyo Inst. of Technology, Tokyo (Japan); Matsumoto, Hideo [Inst. for Integrated Sports Medicine, Keio Univ. School of Medicine, Tokyo (Japan); Yanaihara, Hisashi [Dept. of Diagnostic Radiology, Kitasato Univ. Kitasato Inst. Hospital, Tokyo (Japan); Nishiwaki, Yuji [Dept. of Environmental and Occupational Health, Toho Univ. School of Medicine, Tokyo (Japan); Toyama, Yoshiaki; Matsumoto, Morio [Dept. of Orthopaedic Surgery, Keio Univ. School of Medicine, Tokyo (Japan)

    2012-11-15

    Background Quantification of intervertebral disc degeneration based on intensity of the nucleus pulposus in magnetic resonance imaging (MRI) often uses the mean intensity of the region of interest (ROI) within the nucleus pulposus. However, the location and size of ROI have varied in different reports, and none of the reported methods can be considered fully objective. Purpose To develop a more objective method of establishing ROIs for quantitative evaluation of signal intensity in the nucleus pulposus using T2-weighted MRI. Material and Methods A 1.5-T scanner was used to obtain T2-weighted mid-sagittal images. A total of 288 intervertebral discs from 48 patients (25 men, 23 women) were analyzed. Mean age was 47.4 years (range, 17-69 years). All discs were classified into five grades according to Pfirrmann et al. Discs in grades I and II were defined as bright discs, and discs in grades IV and V were defined as dark discs. Eight candidate methods of ROI determination were devised. The method offering the highest degree of discrimination between bright and dark discs was investigated among these eight methods. Results The method with the greatest degree of discrimination was as follows. The quadrangle formed by anterior and posterior edges of the upper and lower end plates in contact with the intervertebral disc to be measured was defined as the intervertebral area. A shape similar to the intervertebral area but with one-quarter the area was drawn. The geometrical center of the shape was matched to the center of intensity, and this shape was then used as the ROI. Satisfactory validity and reproducibility were obtained using this method. Conclusion The present method offers adequate discrimination and could be useful for longitudinal tracking of intervertebral disc degeneration with sufficient reproducibility.

  2. High-intensity facial nerve lesions on T2-weighted images in chronic persistent facial nerve palsy

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, T. [Dept. of Radiology, Sendai City Hospital, Sendai (Japan); Dept. of Radiology, Tottori Univ. (Japan); Ishii, K. [Dept. of Radiology, Sendai City Hospital, Sendai (Japan); Okitsu, T. [Dept. of Otolaryngology, Sendai City Hospital (Japan); Ogawa, T. [Dept. of Radiology, Tottori Univ. (Japan); Okudera, T. [Dept. of Radiology, Research Inst. of Brain and Blood Vessels-Akita, Akita (Japan)

    2001-05-01

    Our aim was to estimate the value of MRI in detecting irreversibly paralysed facial nerves. We examined 95 consecutive patients with a facial nerve palsy (14 with a persistent palsy, and 81 with good recovery), using a 1.0 T unit, with T2-weighted and contrast-enhanced T1-weighted images. The geniculate ganglion and tympanic segment had gave high signal on T2-weighted images in the chronic stage of persistent palsy, but not in acute palsy. The enhancement pattern of the facial nerve in the chronic persistent facial nerve palsy is similar to that in the acute palsy with good recovery. These findings suggest that T2-weighted MRI can be used to show severely damaged facial nerves. (orig.)

  3. T2-enhanced tensor diffusion trace-weighted image in the detection of hyper-acute cerebral infarction: Comparison with isotropic diffusion-weighted image

    International Nuclear Information System (INIS)

    Chou, M.-C.; Tzeng, W.-S.; Chung, H.-W.; Wang, C.-Y.; Liu, H.-S.; Juan, C.-J.; Lo, C.-P.; Hsueh, C.-J.; Chen, C.-Y.

    2010-01-01

    Background and purpose: Although isotropic diffusion-weighted imaging (isoDWI) is very sensitive to the detection of acute ischemic stroke, it may occasionally show diffusion negative result in hyper-acute stroke. We hypothesize that high diffusion contrast diffusion trace-weighted image with enhanced T2 may improve stroke lesion conspicuity. Methods: Five hyper acute stroke patients (M:F = 0:5, average age = 61.8 ± 20.5 y/o) and 16 acute stroke patients (M:F = 11:5, average age = 67.7 ± 12 y/o) were examined six-direction tensor DWIs at b = 707 s/mm 2 . Three different diffusion-weighted images, including isotropic (isoDWI), diffusion trace-weighted image (trDWI) and T2-enhanced diffusion trace-weighted image (T2E t rDWI), were generated. Normalized lesion-to-normal ratio (nLNR) and contrast-to-noise ratio (CNR) of three diffusion images were calculated from each patient and statistically compared. Results: The trDWI shows better nLNR than isoDWI on both hyper-acute and acute stroke lesions, whereas no significant improvement in CNR. Nevertheless, the T2E t rDWI has statistically superior CNR and nLNR than those of isoDWI and trDWI in both hyper-acute and acute stroke. Conclusions: We concluded that tensor diffusion trace-weighted image with T2 enhancement is more sensitive to stroke lesion detection, and can provide higher lesion conspicuity than the conventional isotropic DWI for early stroke lesion delineation without the need of high-b-value technique.

  4. Radiation necrosis of the optic chiasm, optic tract, hypothalamus, and upper pons after radiotherapy for pituitary adenoma, detected by gadolinium-enhanced, T1-weighted magnetic resonance imaging: Case report

    International Nuclear Information System (INIS)

    Tachibana, O.; Yamaguchi, N.; Yamashima, T.; Yamashita, J.

    1990-01-01

    A 26-year-old woman was treated for a prolactin secreting pituitary adenoma by surgery and radiotherapy (5860 rads). Fourteen months later, she developed right hemiparesis and dysarthria. A T1-weighted magnetic resonance imaging scan using gadolinium contrast showed a small, enhanced lesion in the upper pons. Seven months later, she had a sudden onset of loss of vision, and radiation optic neuropathy was diagnosed. A T1-weighted magnetic resonance imaging scan showed widespread gadolinium-enhanced lesions in the optic chiasm, optic tract, and hypothalamus. Magnetic resonance imaging is indispensable for the early diagnosis of radiation necrosis, which is not visualized by radiography or computed tomography

  5. MR urography (MRU) of non-dilated ureter with diuretic administration: Static fluid 2D FSE T2-weighted versus 3D gadolinium T1-weighted GE excretory MR

    International Nuclear Information System (INIS)

    Roy, C.; Ohana, M.; Host, Ph.; Alemann, G.; Labani, A.; Wattiez, A.; Lang, H.

    2014-01-01

    T2w-MRU with multiple orientations and diuretic is sufficient to identify non-dilated ureter.•T2w-MRU offers information on ureteral contractions and could be proposed to detect initial obstruction before hydronephrosis occurs (for instance in cases of endometriosis).•T2w-MRU could also be used to evaluate potential renal donors or in patients unable to receive gadolinium.•CE-MRU rapidly produces an overdistended bladder with a risk of false positive diagnosis of mild obstruction.•CE-MRU is less convenient for patients. T2w-MRU with multiple orientations and diuretic is sufficient to identify non-dilated ureter. T2w-MRU offers information on ureteral contractions and could be proposed to detect initial obstruction before hydronephrosis occurs (for instance in cases of endometriosis). T2w-MRU could also be used to evaluate potential renal donors or in patients unable to receive gadolinium. CE-MRU rapidly produces an overdistended bladder with a risk of false positive diagnosis of mild obstruction. CE-MRU is less convenient for patients. The goal of this prospective study was to compare the efficiency of two types of MRU after diuretic administration to identify the non-dilated ureter. MR pelvic examinations were performed in 126 patients after receiving furosemide. Each patient underwent in addition to their protocol for context, two types of MRU: 2D T2-weighted FSE (T2w-MRU) and 3D Gd T1-weighted GE (CE-MRU). Four segments were checked for each ureter. For the first part of the analysis, readers evaluated the whole image quality using a four points subjective scale and for the second part, they were asked to score separately each ureteral segment as present or absent. 1008 ureteral segments were checked. For the image quality, readers did not find any significant difference (3.8 ± 0.5 vs 3.6 ± 0.7, p value: 0.13) between MRU methods. The interobserver agreement was excellent with a κ correlation coefficient as high as 0.89 for T2w-MRU and 0.92 for CE

  6. Liver acquisition with acceleration volume acquisition gadolinium-enhanced magnetic resonance combined with T2 sequences in the diagnosis of local recurrence of rectal cancer.

    Science.gov (United States)

    Cao, Wuteng; Li, Fangqian; Gong, Jiaying; Liu, Dechao; Deng, Yanhong; Kang, Liang; Zhou, Zhiyang

    2016-11-22

    To investigate the efficacy of liver acquisition with acceleration volume acquisition (LAVA) gadolinium-enhanced magnetic resonance (MR) sequences and to assess its added accuracy in diagnosing local recurrence (LR) of rectal cancer with conventional T2-weighted fast spin echo (FSE) sequences. Pelvic MRI, including T2-weighted FSE sequences, gadolinium-enhanced sequences of LAVA and T1-weighted FSE with fat suppression, was performed on 225 patients with postoperative rectal cancer. Two readers evaluated the presence of LR according to "T2" (T2 sequences only), "T2 + LAVA-Gad" (LAVA and T2 imaging), and "T2 + T1-fs-Gad" (T1 fat suppression-enhanced sequence with T2 images). To evaluate diagnostic efficiency, imaging quality with LAVA and T1-fs-Gad by subjective scores and the signal intensity (SI) ratio. In the result, the SI ratio of LAVA was significantly higher than that of T1-fs-Gad (p = 0.0001). The diagnostic efficiency of "T2 + LAVA-Gad" was better than that of "T2 + T1-fs-Gad" (p = 0.0016 for Reader 1, p = 0.0001 for Reader 2) and T2 imaging only (p = 0.0001 for Reader 1; p = 0.0001 for Reader 2). Therefore, LAVA gadolinium-enhanced MR increases the accuracy of diagnosis of LR from rectal cancer and could replace conventional T1 gadolinium-enhanced sequences in the postoperative pelvic follow-up of rectal cancer.

  7. Mapping pathological changes in brain structure by combining T1- and T2-weighted MR imaging data

    International Nuclear Information System (INIS)

    Ganzetti, Marco; Mantini, Dante; Wenderoth, Nicole

    2015-01-01

    A workflow based on the ratio between standardized T1-weighted (T1-w) and T2-weighted (T2-w) MR images has been proposed as a new tool to study brain structure. This approach was previously used to map structural properties in the healthy brain. Here, we evaluate whether the T1-w/T2-w approach can support the assessment of structural impairments in the diseased brain. We use schizophrenia data to demonstrate the potential clinical utility of the technique. We analyzed T1-w and T2-w images of 36 schizophrenic patients and 35 age-matched controls. These were collected for the Function Biomedical Informatics Research Network (fBIRN) collaborative project, which had an IRB approval and followed the HIPAA guidelines. We computed T1-w/T2-w images for each individual and compared intensities in schizophrenic and control groups on a voxel-wise basis, as well as in regions of interest (ROIs). Our results revealed that the T1-w/T2-w image permits to discriminate brain regions showing group-level differences between patients and controls with greater accuracy than conventional T1-w and T2-w images. Both the ROIs and the voxel-wise analysis showed globally reduced gray and white matter values in patients compared to controls. Significantly reduced values were found in regions such as insula, primary auditory cortex, hippocampus, inferior longitudinal fasciculus, and inferior fronto-occipital fasciculus. Our findings were consistent with previous meta-analyses in schizophrenia corroborating the hypothesis of a potential ''disconnection'' syndrome in conjunction with structural alterations in local gray matter regions. Overall, our study suggested that the T1-w/T2-w technique permits to reliably map structural differences between the brains of patients and healthy individuals. (orig.)

  8. Mapping pathological changes in brain structure by combining T1- and T2-weighted MR imaging data

    Energy Technology Data Exchange (ETDEWEB)

    Ganzetti, Marco; Mantini, Dante [ETH Zurich, Neural Control of Movement Laboratory, Department of Health Sciences and Technology, Zurich (Switzerland); University of Oxford, Department of Experimental Psychology, Oxford (United Kingdom); Wenderoth, Nicole [ETH Zurich, Neural Control of Movement Laboratory, Department of Health Sciences and Technology, Zurich (Switzerland); KU Leuven, Laboratory of Movement Control and Neuroplasticity, Faculty of Kinesiology and Rehabilitation Sciences, Leuven (Belgium)

    2015-09-15

    A workflow based on the ratio between standardized T1-weighted (T1-w) and T2-weighted (T2-w) MR images has been proposed as a new tool to study brain structure. This approach was previously used to map structural properties in the healthy brain. Here, we evaluate whether the T1-w/T2-w approach can support the assessment of structural impairments in the diseased brain. We use schizophrenia data to demonstrate the potential clinical utility of the technique. We analyzed T1-w and T2-w images of 36 schizophrenic patients and 35 age-matched controls. These were collected for the Function Biomedical Informatics Research Network (fBIRN) collaborative project, which had an IRB approval and followed the HIPAA guidelines. We computed T1-w/T2-w images for each individual and compared intensities in schizophrenic and control groups on a voxel-wise basis, as well as in regions of interest (ROIs). Our results revealed that the T1-w/T2-w image permits to discriminate brain regions showing group-level differences between patients and controls with greater accuracy than conventional T1-w and T2-w images. Both the ROIs and the voxel-wise analysis showed globally reduced gray and white matter values in patients compared to controls. Significantly reduced values were found in regions such as insula, primary auditory cortex, hippocampus, inferior longitudinal fasciculus, and inferior fronto-occipital fasciculus. Our findings were consistent with previous meta-analyses in schizophrenia corroborating the hypothesis of a potential ''disconnection'' syndrome in conjunction with structural alterations in local gray matter regions. Overall, our study suggested that the T1-w/T2-w technique permits to reliably map structural differences between the brains of patients and healthy individuals. (orig.)

  9. MR imaging of skeletal muscle injury in rabbit : comparison between diffusion and T2-weighted MR images

    International Nuclear Information System (INIS)

    Kim, Ki Jun; Lee, Sung Yong; Lee, Jae Hee; Kwon Oh Han; Lee, Jae Mun; Lim, Yeon Soo

    2000-01-01

    The purpose of this study was to apply the diffusion-weighted MR imaging technique to the early detection of skeletal muscle injury and to evaluate the usefulness of this imaging sequence. Thirty rabbits, divided into two groups, were included in this study . Skeletal muscle injury was experimentally induced in the right thigh muscles of each rabbit by clamping with a hemostat for one minute. Four-stage clamping was applied to the rabbits in group I, but for group II there was only one stage. Diffusion and T2-weighted MR images were obtained using a 1.5T MR unit. Serial 5-and 30-minute, and 2-, 24-, and 48- hour delayed images were obtained after injury. The initial time of signal intensity change was recorded and the signal intensities of the injured sites and corresponding normal sites were measured and compared. On 5-minute delayed images in group I, diffusion-weighted MR images showed signal intensity changes in injured muscle in all 15 cases, but on T2-weighted images, change was not detected in three cases. In group II, 5-minute delayed T2-weighted images failed to depict the lesion in six cases, but on diffusion-weighted images, all lesions were detected. In addition, one lesion was not detected on 30-minute delayed T2-weighted images. In group II, the sensitivity of lesion detection was significantly higher on diffusion-weighted than on T2-weighted images (p=3D0.0169). Diffusion-weighted MR imaging was shown to be more sensitive than T2-weighted imaging for the detection of signal intensity changes immediately after artificial injury, especially when this was of a lesser degree. These results suggest that diffusion-weighted MR imaging may be useful for the detection of early stage skeletal muscle injury. (author)

  10. Myometrial invasion in endometrial cancer: diagnostic performance of diffusion-weighted MR imaging at 1.5-T

    International Nuclear Information System (INIS)

    Rechichi, Gilda; Sironi, Sandro; Galimberti, Stefania; Valsecchi, Maria Grazia; Signorelli, Mauro; Perego, Patrizia

    2010-01-01

    To determine the diagnostic accuracy of diffusion-weighted (DW) magnetic resonance (MR) imaging in the preoperative assessment of myometrial invasion by endometrial cancer. In this prospective study, 47 patients with histologically confirmed endometrial cancer underwent preoperative MR imaging and total hysterectomy. The MR protocol included spin-echo multishot T2-weighted, dynamic T1-weighted and DW images acquired with b-values of 0 and 500 s/mm 2 . Myometrial tumour spread was classified as superficial (<50%) or deep (≥50% myometrial thickness). Postoperative histopathological findings served as a reference standard. Indices of diagnostic performance were assessed for each sequence. At histopathological examination, superficial myometrial invasion was found in 34 patients and deep myometrial invasion in 13. In the assessment of tumour invasion, sensitivity, specificity, positive and negative predictive values of T2-weighted images were 92.3%, 76.5%, 60.0% and 96.3%, respectively. The corresponding values for dynamic images were 69.2%, 61.8%, 40.9% and 84.0%, and for DW images 84.6%, 70.6%, 52.4% and 92.3%. T2-weighted and DW imaging proved to be the most accurate techniques for tumour spread determination. DW imaging proved to be accurate in assessing myometrial invasion, and it could replace dynamic imaging as an adjunct to routine T2-weighted imaging for preoperative evaluation of endometrial cancer. (orig.)

  11. The image evaluation of iterative motion correction reconstruction algorithm PROPELLER T2-weighted imaging compared with MultiVane T2-weighted imaging

    Science.gov (United States)

    Lee, Suk-Jun; Yu, Seung-Man

    2017-08-01

    The purpose of this study was to evaluate the usefulness and clinical applications of MultiVaneXD which was applying iterative motion correction reconstruction algorithm T2-weighted images compared with MultiVane images taken with a 3T MRI. A total of 20 patients with suspected pathologies of the liver and pancreatic-biliary system based on clinical and laboratory findings underwent upper abdominal MRI, acquired using the MultiVane and MultiVaneXD techniques. Two reviewers analyzed the MultiVane and MultiVaneXD T2-weighted images qualitatively and quantitatively. Each reviewer evaluated vessel conspicuity by observing motion artifacts and the sharpness of the portal vein, hepatic vein, and upper organs. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated by one reviewer for quantitative analysis. The interclass correlation coefficient was evaluated to measure inter-observer reliability. There were significant differences between MultiVane and MultiVaneXD in motion artifact evaluation. Furthermore, MultiVane was given a better score than MultiVaneXD in abdominal organ sharpness and vessel conspicuity, but the difference was insignificant. The reliability coefficient values were over 0.8 in every evaluation. MultiVaneXD (2.12) showed a higher value than did MultiVane (1.98), but the difference was insignificant ( p = 0.135). MultiVaneXD is a motion correction method that is more advanced than MultiVane, and it produced an increased SNR, resulting in a greater ability to detect focal abdominal lesions.

  12. Signal-to-noise ratio, T2 , and T2* for hyperpolarized helium-3 MRI of the human lung at three magnetic field strengths.

    Science.gov (United States)

    Komlosi, Peter; Altes, Talissa A; Qing, Kun; Mooney, Karen E; Miller, G Wilson; Mata, Jaime F; de Lange, Eduard E; Tobias, William A; Cates, Gordon D; Mugler, John P

    2017-10-01

    To evaluate T 2 , T2*, and signal-to-noise ratio (SNR) for hyperpolarized helium-3 ( 3 He) MRI of the human lung at three magnetic field strengths ranging from 0.43T to 1.5T. Sixteen healthy volunteers were imaged using a commercial whole body scanner at 0.43T, 0.79T, and 1.5T. Whole-lung T 2 values were calculated from a Carr-Purcell-Meiboom-Gill spin-echo-train acquisition. T2* maps and SNR were determined from dual-echo and single-echo gradient-echo images, respectively. Mean whole-lung SNR values were normalized by ventilated lung volume and administered 3 He dose. As expected, T 2 and T2* values demonstrated a significant inverse relationship to field strength. Hyperpolarized 3 He images acquired at all three field strengths had comparable SNR values and thus appeared visually very similar. Nonetheless, the relatively small SNR differences among field strengths were statistically significant. Hyperpolarized 3 He images of the human lung with similar image quality were obtained at three field strengths ranging from 0.43T and 1.5T. The decrease in susceptibility effects at lower fields that are reflected in longer T 2 and T2* values may be advantageous for optimizing pulse sequences inherently sensitive to such effects. The three-fold increase in T2* at lower field strength would allow lower receiver bandwidths, providing a concomitant decrease in noise and relative increase in SNR. Magn Reson Med 78:1458-1463, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  13. Magnetism and superconductivity in CeFe2-xTxAs2 (T = Co and Ni) single crystals

    International Nuclear Information System (INIS)

    Thamizhavel, A.

    2010-01-01

    Single crystals of pure and transition metal doped CaFe 2- x T x As 2 (T = Co and Ni) have been grown by flux method using molten Sn as solvent. The magnetic and superconducting properties of the grown crystals were studied by measuring the electrical resistivity, magnetic susceptibility and neutron diffraction measurements. A spin density wave (SDW)/structural transition is observed at 170 K for the pure CaFe 2 As 2 single crystal and it gets suppressed with T (Co and Ni) doping. For an optimum dopant concentration of x = 0.06, the sample becomes superconducting. From the detailed studies on CaFe 2- x Ni x As 2 single crystals we have constructed a magnetic phase diagram. (author)

  14. Gadoxate-enhanced T1-weighted MR cholangiography: comparison of 1.5 T and 3.0 T

    Energy Technology Data Exchange (ETDEWEB)

    Koelblinger, C.; Schima, W.; Weber, M.; Mang, T.; Nemec, S.; Kulinna-Cosentini, C.; Bastati, N.; Ba-Ssalamah, A. [Universitaetsklinik fuer Radiodiagnostik, Medizinische Univ. Wien (Austria)

    2009-06-15

    Purpose: to qualitatively and quantitatively compare gadoxate-enhanced T1-weighted MR cholangiography at magnetic field strengths of 1.5 T and 3.0 T. Materials and methods: a total of 40 patients with a non-dilated biliary system were retrospectively included in the study. T1-weighted MR cholangiography 20 min after IV administration of 0.025 mmol/kg gadoxate (Primovist trademark) was performed in 20 patients at 1.5 T and in another 20 patients at 3.0 T. Contrast-to-noise ratios (CNR) of the biliary system (common bile duct - CBD, right hepatic duct - RHD, left hepatic duct - LHD) compared to the periductal tissue were measured. Two radiologists also qualitatively assessed the visibility of the intrahepatic and extrahepatic biliary system using a six-point rating scale. The Mann-Whitney U-test and Pearson's correlation coefficient were used for statistical analysis. Results: the CNRs of the intrahepatic and extrahepatic hepatic bile ducts were significantly higher at 3.0 T. Qualitative analysis showed a significant superiority for 3.0 T in the delineation of the intrahepatic biliary system (RHD, LHD, segmental ducts). (orig.)

  15. Magnetic resonance imaging of epidermoid, including diffusion weighted images and an atypical case

    International Nuclear Information System (INIS)

    Takahashi, Shoki; Higano, Shuichi; Kurihara, Noriko

    1994-01-01

    In order to study the role of magnetic resonance imaging (MRI) in diagnosing intracranial epidermoid, we evaluated the MRI findings on five cases with such tumor, all of which were surgically verified. In addition to standard spin-echo (SE) images obtained in all cases, diffusion-weighted images were acquired in two patients. In four patients, the tumor revealed to be almost isointense relative to cerebrospinal fluid (CSF) on both T 1 -and T 2 -weighted images, while it tended to show slightly hyperintense to CSF on proton-density-weighted images; thus, based on the signal intensity on standard SE images the distinction between epidermoid and arachnoid cyst may be difficult. Furthermore, the presence of the tumor which has a tendency to grow in and along the subarachnoid space causing relatively minimal mass effect may be overlooked. Diffusion-weighted images were shown to have advantages in such cases by demonstrating the tumor unequivocally as a mass of high signal, and differentiating it from arachnoid cysts. In the remaining patient, its appearance was atypical, showing bright signal on both T 1 -and T 2 -weighted images. In conclusion free of bone artifacts, multiplanar MRI with additional diffusion-weighted images provides a clear demonstration of epidermoid, and its differentiation from arachnoid cyst, thus obviating the need for CT cisternography. (author)

  16. Effect of endorsed body weight on specific absorption rate during magnetic resonance imaging

    International Nuclear Information System (INIS)

    Singh, Harish K.; Gupta, R.K.; Gujral, R.B.; Shukla, A.K.

    2001-01-01

    As a routine safety of the patients undergoing magnetic resonance imaging (MRI), the limits of radiofrequency (RF) specific absorption rate (SAR) are set by the manufacturers of all MRI systems because RF causes thermo genesis of the RF exposed tissue. It has been mandatory practice to endorse body weight and age of the patients required by the MRI systems for the SAR check. The problems arise on those patients who are critically ill, and consequently body weight could not be measured. In such cases, approximate body weight has to be endorsed. In case of underweight and overweight patients, sometimes SAR check does not permit to run the MRI pulse sequences. Also, in such cases, body weight remains the parameter which is being changed to get the MRI done. The purpose of this study is to assess the change of SAR with endorsed body weight. The change of SAR was recorded with the endorsed weight using phantoms and most commonly used T1 and T2 weighted pulse sequence on clinical MRI system. At true endorsed weight, using respective coils and the head and spine coil phantoms, the body averaged and localised SAR were found to be within limits while this was not the case with body coil phantom. Unrealistic endorsed weights are permissible for the adult age cases in all coils while using the routine T1 and T2 weighted pulse sequences. This finding is absolutely new in the field and certainly, will be of great applicability to develop a uniform and standard system of SAR checks in the patient interest. (author)

  17. Liquid helium-free 15 T superconducting magnet at 4 K

    International Nuclear Information System (INIS)

    Sakuraba, J.; Mikami, Y.; Watazawa, K.; Watanabe, K.; Awaji, S.

    2000-01-01

    We have successfully demonstrated a 15.1 T liquid helium-free superconducting magnet with a room-temperature bore of 52 mm using a Nb 3 Sn/NbTi hybrid coil, Bi2223 current leads and two Gifford-McMahon cryocoolers. The magnet has 830 mm outside diameter, 1221 mm height and 720 kg weight. The magnet was cooled to 3.6 K in 114 h. A central magnetic field of 15.1 T was achieved in 38 min. The temperature of the coil increased to 5.7 K due to ac losses during the excitation, but it decreased to 4.0 K before reaching 15.1 T. The temperature of the coil remained at a constant value of 3.8 K over the 24 h of operation. The demonstration indicated the usefulness of a liquid helium-free superconducting magnet to generate high magnetic fields up to 15 T. (author)

  18. Signal void dots on T2-weighted brain MR images in patients with hypertensive intracerebral hemorrhage : Its nature and clinical significance

    International Nuclear Information System (INIS)

    Kim, Sang Joon; Yoo, Dong Soo; Kim, Seung Chul; Kim, Tae Hoon; Kim, Jae Seung; Kim, Jae Il

    1997-01-01

    To describe the signal void dots found on T2-weighted magnetic resonance (MR) images of the brain in hypertensive patients. Conventional T2-weighted MR images of 11 patients with hypertensive intracerebral hemorrhage (ICH), 14 with lacunar infarction and 11 comprising a normal control group aged over 60 were analyzed with regard to the presence, location, number and size of signal void dots. We also evaluated their relationship to hypertension. We performed time-of-flight or phase contrast MR angiography, gradient echo pulse sequences, or conventional cerebral angiography in some hypertensive ICH patients and compared them with corresponding T2-weighted images. Signal void dots were found in all patients with hypertensive ICH. Six of 14 patients with lacunar infarction showed these dots;all six suffered from hypertension. The dots were located in the thalami, pons and basal ganglia, and were measured as 1 to 4mm in diameter, mostly 2mm;they looked larger on gradient echo images. In the normal control group there were no signal void dots, and on MR or conventional angiography, no vascular ectasia was noted at the site corresponding to the signal void dots. Signal void dots were not considered to be part of the normal aging process, but appeared to be closely related to hypertension and ICH. The dots were thought to be due to the susceptibility effect of blood degradation product rather than to flow artifact or enlarged vessels. The thrombosed microaneurysm with or without surrounding microleakage of blood may explain the nature of signal void dots on T2-weighted images of hypertensive brain

  19. Utility of single shot fast spin echo technique in evaluating pancreaticobiliary diseases: T2-weighted image and magnetic resonance cholangiopancreatography

    International Nuclear Information System (INIS)

    Choi, Byoung Wook; Kim, Myeong Jin; Chung, Jae Bok; Ko, Heung Kyu; Kim, Dong Joon; Kim, Joo Hee; Chung, Jae Joon; Yoo, Hyung Sik; Lee, Jong Tae

    1999-01-01

    To evaluate the accuracy of T2-weighted imaging an MR cholangiopancreatography using the single shot fast spin-echo technique for evaluating pancreaticobiliary disease. Between March and July 1997, axial and coronal T2-weighted images(TE: 80-200 msec) and MR cholangiopancreatograms (TE: 800-1200 msec) were obtained in two ways [single slab (thickness: 30-50 mm) and multislice acquisition under chemical fat saturation] using SSFSE pulse sequencing in 131 cases of suspected pancreati-cobiliary disease. The accuracy of SSFSE MR imaging was assessed in 89 lesions of 74 patients [male, 48; female, 26; age range, 30-86 (mean, 59) years] confirmed surgicopathologically (50 lesions in 39 patients) and clinically (39 lesions in 35 patients). Two radiologists reviewed the MR images and diagnosis was determined by consensus. Correct diagnosis was confirmed in 84 of 89 lesions (94%). Seven lesions were falsely interpreted, false positive and false negative results accounting for two and five cases, respectively. Two pancreatic cancers were misdiagnosed as pancreatitis and a cancer of the proximal common bile duct(CBD) was interpreted as a distal CBD cancer. The sensitivity of SSFSE MR imaging for malignancy was 93 %. One CBD stone revealed by endoscopic retrograde cholangiopancreatography (ERCP) was not detected on MR images. In contrast, a stone in the CBD seen on MR images was not apparent on subsequent ERCP. Sensitivity and specificity for calculous disease were 96% and 99.7%, respectively. A benign stricture of the ampulla of Vater was falsely interpreted as normal, and correct diagnosis was possible in two falsely diagnosed cases when MR images were reviewed retrospectively. The combination of T2-weighted and cholangiographic images using SSFSE is an accurate method for diagnosing pancreatcobiliary diseases

  20. Magnetic resonance fingerprinting using echo-planar imaging: Joint quantification of T1 and T2∗ relaxation times.

    Science.gov (United States)

    Rieger, Benedikt; Zimmer, Fabian; Zapp, Jascha; Weingärtner, Sebastian; Schad, Lothar R

    2017-11-01

    To develop an implementation of the magnetic resonance fingerprinting (MRF) paradigm for quantitative imaging using echo-planar imaging (EPI) for simultaneous assessment of T 1 and T2∗. The proposed MRF method (MRF-EPI) is based on the acquisition of 160 gradient-spoiled EPI images with rapid, parallel-imaging accelerated, Cartesian readout and a measurement time of 10 s per slice. Contrast variation is induced using an initial inversion pulse, and varying the flip angles, echo times, and repetition times throughout the sequence. Joint quantification of T 1 and T2∗ is performed using dictionary matching with integrated B1+ correction. The quantification accuracy of the method was validated in phantom scans and in vivo in 6 healthy subjects. Joint T 1 and T2∗ parameter maps acquired with MRF-EPI in phantoms are in good agreement with reference measurements, showing deviations under 5% and 4% for T 1 and T2∗, respectively. In vivo baseline images were visually free of artifacts. In vivo relaxation times are in good agreement with gold-standard techniques (deviation T 1 : 4 ± 2%, T2∗: 4 ± 5%). The visual quality was comparable to the in vivo gold standard, despite substantially shortened scan times. The proposed MRF-EPI method provides fast and accurate T 1 and T2∗ quantification. This approach offers a rapid supplement to the non-Cartesian MRF portfolio, with potentially increased usability and robustness. Magn Reson Med 78:1724-1733, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  1. Cerebral Fat Embolism: Diffusion-weighted Magnetic Resonance Imaging Findings

    International Nuclear Information System (INIS)

    Ryu, C.W.

    2005-01-01

    PURPOSE: To demonstrate the diffusion-weighted (DWI) magnetic resonance imaging (MRI) findings, and the follow-up MRI findings, of cerebral fat embolism in the acute stage. MATERIAL AND METHODS: The initial DWI and clinical findings of six patients with cerebral fat embolism were retrospectively evaluated. The finding of DWI with a b-value of 1000 s/mm 2 (b=1000) was compared with that of DWI with a b-value of 0 s/mm 2 (b=0). In three patients who underwent follow-up MRI, the interval change of the lesion on T2-weighted images was investigated. RESULTS: The characteristic DWI finding of cerebral fat embolism in the acute stage was multiple, hyperintense, dot-like lesions disseminated in the brain. These lesions were distributed dominantly in the bilateral border-zone areas. Some lesions had an ancillary location including the cortex, deep white matter, basal ganglia, and cerebellum. The lesions were more intense and numerous in DWI (b=1000) than in DWI (b=0). The findings on the follow-up T2-weighted images were multiple confluent hyperintense lesions in the white matter with progression since the initial MRI. CONCLUSION: DWI could be a sensitive tool for detecting cerebral fat embolism in the acute phase. It is recommended that DWI be included in the initial evaluation of cerebral fat embolism with MRI

  2. Scaled signal intensity of uterine fibroids based on T2-weighted MR images: a potential objective method to determine the suitability for magnetic resonance-guided focused ultrasound surgery of uterine fibroids

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyun [CHA University, Comprehensive Gynecologic Cancer Center, CHA Bundang Medical Center, Gyunggi-do (Korea, Republic of); Yoon, Sang-Wook [CHA University, Department of Diagnostic Radiology, CHA Bundang Medical Center, Sungnam-si, Gyunggi-do (Korea, Republic of); Sokolov, Amit [InSightec Ltd., Haifa (Israel)

    2015-12-15

    Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS) is a non-invasive method to treat uterine fibroids. To help determine the patient suitability for MRgFUS, we propose a new objective measure: the scaled signal intensity (SSI) of uterine fibroids in T2 weighted MR images (T2WI). Forty three uterine fibroids in 40 premenopausal women were included in this retrospective study. SSI of each fibroid was measured from the screening T2WI by standardizing its mean signal intensity to a 0-100 scale, using reference intensities of rectus abdominis muscle (0) and subcutaneous fat (100). Correlation between the SSI and the non-perfused volume (NPV) ratio (a measure for treatment success) was calculated. Pre-treatment SSI showed a significant inverse-correlation with post treatment NPV ratio (p < 0.05). When dichotomizing NPV ratio at 45 %, the optimal cut off value of the SSI was found to be 16.0. A fibroid with SSI value 16.0 or less can be expected to have optimal responses. The SSI of uterine fibroids in T2WI can be suggested as an objective parameter to help in patient selection for MRgFUS. (orig.)

  3. Evaluation of renal function with dynamic MRI-T2-weighted gradient echo technique

    International Nuclear Information System (INIS)

    Kato, Katsuya

    1995-01-01

    To evaluate the usefulness of dynamic MRI of kidneys in healthy volunteers and patients with different 24-hour creatinine clearance (Ccr) levels, a dynamic study that employed the T2 weighted gradient echo technique (FLASH: TR/TE=34/25 msec, flip angle= 20 degrees) with single images during breathhold was performed on 10 healthy volunteers and 35 patients, all examined for the Ccr and suspected of having renal parenchymal disease after a phantom study. T1-weighted and dynamic MR imagings were obtained with a 1.5T imager. I analyzed the time-intensity curve of renal cortex and medulla, and defined a cortex decreased ratio (CDR) and medulla decreased ratio (MDR) in comparison with the Ccr. The cortico-medullary difference ratio (CMDR) of T1WI was also compared with the Ccr. The parameters of the T2 dynamic MRI study (CDR, MDR) better correlated with the Ccr than CMDR. Renal function can be quantitatively evaluated with the T2 dynamic MRI and there is a possibility that we can qualitatively evaluate the renal dysfunction and estimate its cause. (author)

  4. Fat-suppressed T2-weighted MRI appearance of subchondral insufficiency fracture of the femoral head

    Energy Technology Data Exchange (ETDEWEB)

    Sonoda, Kazuhiko; Yamamoto, Takuaki; Motomura, Goro; Karasuyama, Kazuyuki; Kubo, Yusuke; Iwamoto, Yukihide [Kyushu University, Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Higashi-ku, Fukuoka (Japan)

    2016-11-15

    Our aims were to investigate the imaging appearance of subchondral insufficiency fracture (SIF) of the femoral head based on fat-suppressed T2-weighted MRI, and evaluate its correlation with the clinical outcomes following conservative treatment. We retrospectively evaluated 40 hips in 37 patients with SIF of the femoral head (12 males and 25 females; mean age 55.8 years, range 22-78 years). MRI examinations were performed within 3 months after the onset of hip pain. Using fat-suppressed T2-weighted imaging, we evaluated the hips for the intensity of the subchondral bone (corresponding to the area superior to the low intensity band on T1-weighted images) as well as bone marrow edema, joint effusion, and presence of the band lesion. We then correlated the intensity of the subchondral bone with clinical outcomes. The hips were classified into three types based on subchondral intensity on fat-suppressed T2-weighted images: type 1 (21 hips) showed high intensity, type 2 (eight hips) showed heterogeneous intensity, and type 3 (11 hips) showed low intensity. The mean period between pain onset and MRI examination was significantly longer for type 2 hips than for type 1. Healing rates were 86 % for type 1, 75 % for type 2, and 18 % for type 3. SIF cases were classified into three types based on subchondral intensity on fat-suppressed T2-weighted imaging performed within 3 months after pain onset. Type 3 SIF tended to be intractable to conservative treatment compared to type 1 and type 2. (orig.)

  5. Operator analysis of physical states on magnetized T{sup 2}/Z{sub N} orbifolds

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Tomo-hiro, E-mail: t-abe@scphys.kyoto-u.ac.jp [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Fujimoto, Yukihiro, E-mail: Fujimoto@het.phys.sci.osaka-u.ac.jp [Department of Physics, Osaka University, Toyonaka 560-0043 (Japan); Kobayashi, Tatsuo, E-mail: kobayashi@particle.sci.hokudai.ac.jp [Department of Physics, Hokkaido University, Sapporo 060-0810 (Japan); Miura, Takashi, E-mail: takashi.miura@people.kobe-u.ac.jp [Department of Physics, Kobe University, Kobe 657-8501 (Japan); Nishiwaki, Kenji, E-mail: nishiken@kias.re.kr [Regional Centre for Accelerator-based Particle Physics, Harish-Chandra Research Institute, Allahabad 211 019 (India); School of Physics, Korea Institute for Advanced Study, Seoul 130 722 (Korea, Republic of); Sakamoto, Makoto, E-mail: dragon@kobe-u.ac.jp [Department of Physics, Kobe University, Kobe 657-8501 (Japan)

    2015-01-15

    We discuss an effective way for analyzing the system on the magnetized twisted orbifolds in operator formalism, especially in the complicated cases T{sup 2}/Z{sub 3}, T{sup 2}/Z{sub 4} and T{sup 2}/Z{sub 6}. We can obtain the exact and analytical results which can be applicable for any larger values of the quantized magnetic flux M, and show that the (non-diagonalized) kinetic terms are generated via our formalism and the number of the surviving physical states are calculable in a rigorous manner by simply following usual procedures in linear algebra in any case. Our approach is very powerful when we try to examine properties of the physical states on (complicated) magnetized orbifolds T{sup 2}/Z{sub 3}, T{sup 2}/Z{sub 4}, T{sup 2}/Z{sub 6} (and would be in other cases on higher-dimensional torus) and could be an essential tool for actual realistic model construction based on these geometries. (Note: This article is registered under preprint number: (arXiv:1409.5421).)

  6. Value of black blood T2* cardiovascular magnetic resonance

    Directory of Open Access Journals (Sweden)

    Carpenter John Paul

    2011-03-01

    Full Text Available Abstract Purpose To assess whether black blood T2* cardiovascular magnetic resonance is superior to conventional white blood imaging of cardiac iron in patients with thalassaemia major (TM. Materials and methods We performed both conventional white blood and black blood T2* CMR sequences in 100 TM patients to determine intra and inter-observer variability and presence of artefacts. In 23 patients, 2 separate studies of both techniques were performed to assess interstudy reproducibility. Results Cardiac T2* values ranged from 4.5 to 43.8 ms. The mean T2* values were not different between black blood and white blood acquisitions (20.5 vs 21.6 ms, p = 0.26. Compared with the conventional white blood diastolic acquisition, the coefficient of variance of the black blood CMR technique was superior for intra-observer reproducibility (1.47% vs 4.23%, p Conclusions Black blood T2* CMR has superior reproducibility and reduced imaging artefacts for the assessment of cardiac iron, in comparison with the conventional white blood technique, which make it the preferred technique for clinical practice.

  7. Magnetic resonance characteristics and susceptibility weighted imaging of the brain in gadolinium encephalopathy.

    Science.gov (United States)

    Samardzic, Dejan; Thamburaj, Krishnamoorthy

    2015-01-01

    To report the brain imaging features on magnetic resonance imaging (MRI) in inadvertent intrathecal gadolinium administration. A 67-year-old female with gadolinium encephalopathy from inadvertent high dose intrathecal gadolinium administration during an epidural steroid injection was studied with multisequence 3T MRI. T1-weighted imaging shows pseudo-T2 appearance with diffusion of gadolinium into the brain parenchyma, olivary bodies, and membranous labyrinth. Nulling of cerebrospinal fluid (CSF) signal is absent on fluid attenuation recovery (FLAIR). Susceptibility-weighted imaging (SWI) demonstrates features similar to subarachnoid hemorrhage. CT may demonstrate a pseudo-cerebral edema pattern given the high attenuation characteristics of gadolinium. Intrathecal gadolinium demonstrates characteristic imaging features on MRI of the brain and may mimic subarachnoid hemorrhage on susceptibility-weighted imaging. Identifying high dose gadolinium within the CSF spaces on MRI is essential to avoid diagnostic and therapeutic errors. Copyright © 2013 by the American Society of Neuroimaging.

  8. Magnetic resonance tomography (MR) of intracranial tumours: Contrast versus T2-weighted tomograms

    International Nuclear Information System (INIS)

    Schoerner, W.; Laniado, M.; Claussen, C.; Kazner, E.; Niendorf, H.P.; Felix, R.

    1986-01-01

    Nuclear magnetic resonance tomography was performed on 38 patients with intracranial tumours, before and after the administration of contrast, using a 0.35 T Magnetom. The MR examinations included various plain spin-echo sequences (SE 400/35, 800/35, 1600/35, 1600/70, 1600/105, 1600/120) as well as examinations after the iv-administration of gadolinium-DTPA (SE 800/35). On all occasions, the abnormalities were visible without contrast. Differentiation of tumour and its surroundings was possible in 19 out of 38 cases without contrast. Delineation of expansively growing tumours (eg. meningiomas) was possible in twelve out of 14 cases, but in only seven out of 24 cases with infiltrating tumours (eg. glioblastomas). On the other hand, clear differentiation between tumour and adjacent edema and normal brain, respectively, was possible in 35 out of 38 cases after Gadolinium-DTPA. (orig.) [de

  9. Clinical Study White Matter Atrophy in Patients with Mesial Temporal Lobe Epilepsy: Voxel-Based Morphometry Analysis of T1- and T2-Weighted MR Images

    International Nuclear Information System (INIS)

    Braga, B.; Yasuda, C.L.; Cendes, F.

    2012-01-01

    Introduction. Mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis is highly refractory to clinical treatment. MRI voxel-based morphometry (VBM) of T1-weighted images has revealed a widespread pattern of gray matter (GM) and white matter (WM) atrophy in MTLE. Few studies have investigated the role of T2-weighted images in revealing WM atrophy using VBM. Objectives. To compare the results of WM atrophy between T1- and T2-weighted images through VBM. Methods. We selected 28 patients with left and 27 with right MTLE and 60 normal controls. We analyzed T1- and T2- weighted images with SPM8, using VBM/DARTEL algorithm to extract maps of GM and WM. The second level of SPM was used to investigate areas of WM atrophy among groups. Results. Both acquisitions showed bilateral widespread WM atrophy. T1-weighted images showed higher sensibility to detect areas of WM atrophy in both groups of MTLE. T2-weighted images also showed areas of WM atrophy in a more restricted pattern, but still bilateral and with a large area of superposition with T1-weighted images. Conclusions. In MTLE, T1-weighted images are more sensitive to detect subtle WM abnormalities using VBM, compared to T2 images, although both present a good superposition of statistical maps. 1. Introduction The mesial temporal lobe epilepsy (MTLE) is highly refractory to pharmacological treatment [1], and it is the main group of epilepsy referred to the tertiary care hospitals for surgical treatment [2]. MTLE shows a good surgical prognosis, with satisfactory seizures control in 60-80% of the patients [3]. In approximately 65%

  10. Apparent Diffusion Coefficient Maps of Pediatric Mass Lesions with Free-Breathing Diffusion-Weighted Magnetic Resonance: Feasibility Study

    International Nuclear Information System (INIS)

    Olsen, Oe.E.; Sebire, N.J.

    2006-01-01

    Purpose: To assess the technical feasibility of apparent diffusion coefficient (ADC) mapping based on free-breathing diffusion-weighted magnetic resonance (DW-MR) outside the CNS in children. Material and Methods: Twelve children with mass lesions of varied histopathology were scanned with short-tau inversion recovery (STIR), contrast-enhanced T1-weighted (CE-T1W), and diffusion-weighted (b = 0, 500 and 1,000 s/mm 2 ) sequences. ADC maps were calculated. Lesion-to-background signal intensity ratios were measured and compared between STIR/CE-T1W/ADC overall (Friedman test) and between viable embryonal tumors and other lesions (Kruskal-Wallis test). Results: ADC maps clearly depicted all lesions. Lesion-to-background signal intensity ratios of STIR (median 3.7), CE-T1W (median 1.4), and ADC (median 1.6) showed no overall difference (chi-square = 3.846; P = 0.146), and there was no difference between viable embryonal tumors and other lesions within STIR/CE-T1W/ADC (chi-square 1.118/0.669/<0.001; P = 0.290/0.414/1.000, respectively). Conclusion: ADC mapping is feasible in free-breathing imaging of pediatric mass lesions outside the CNS using standard clinical equipment. Keywords: Diffusion-weighted magnetic resonance imaging; infants and children; neoplasms

  11. Comparison between FLAIR images and T2-weighted fast spin-echo images of cerebral territory and lacunar infarction

    International Nuclear Information System (INIS)

    Paeng, Mi Hye; Choi, Hye-Young; Lim, Soo Mee; Lee, Jung Sik

    2003-01-01

    To assess the significance of fluid-attenuated inversion recovery (FLAIR) magnetic resonance (MR) imaging in the diagnosis of intracranial infarctions and to find out differential points between central lacunar infarctions and perivascular spaces. We consecutively selected 25 cases of territorial infarction in 20 patients, 37 cases of central infarction in 40 patients, and 30 patients with perivascular space. Signal intensity and lesion conspicuity were analyzed and compared between FLAIR and FSE T2-weighted images, and differences in signal intensity between central infarction and perivascular spaces were determined. Lesion conspicuity for FLAIR was better than for T2-weighted images in 12 and 15, worse in 4 and 24, and similar in 9 and 16 of territorial and central infarctions, respectively. In nine cases of territorial and one case of central infarction, there was associated hemorrhage. At FLAIR imaging, perivascular spaces showed a fine round low signal without a peripheral high signal rim in 17 patients but no demonstrable signals in 15. Differential diagnosis of perivascular spaces and central infarction was thus not difficult. FLAIR MRI was useful in the diagnosis of infarctions and in differentiating between central small lacular infarctions and perivascular spaces

  12. Uterine Artery Embolization for Symptomatic Fibroids with High Signal Intensity on T2-Weighted MR Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Suyon; Kim, Man Deuk; Lee, Myung Su; Lee, Mu Sook; Park, Sung Il; Won, Jong Yun; Lee, Do Yun; Lee, Kwang Hun [Dept. of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Severance Hospital, Seoul (Korea, Republic of)

    2012-09-15

    To evaluate the effectiveness of uterine artery embolization (UAE) for treating symptomatic fibroids with high signal intensity (SI) on magnetic resonance (MR) T2-weighted imaging (T2WI). A total of 537 cases, consisting of 14 patients with high SI fibroids on T2WI (T2 high group), were retrospectively included and compared with 28 randomly selected patients with low SI fibroids on T2WI (control group). High SI of a predominant fibroid on T2WI was defined as having the same or higher SI than the myometrium. Patient ages ranged from 28 to 52 years (mean, 38.1 years). All patients underwent MRI before and after UAE. Predominant fibroid and uterine volumes were calculated with MR images. Symptom status in terms of menorrhagia and dysmenorrhea was scored on a scale of 0-10, with 0 being no symptoms and 10 being the baseline, or initial symptoms. Of the patients in the T2 high group, 13 out of 14 (92.9%) patients demonstrated complete necrosis of the predominant fibroids. The mean volume reduction rates of the predominant fibroids in the T2 high group was 61.7% at three months after UAE, which was significantly higher than the volume reduction rates of 42.1% noted in the control group (p < 0.05). Changes in symptom scores for menorrhagia and dysmenorrhea after UAE (baseline score minus follow-up score) were 4.9 and 7.5 in T2 high group and they were 5.0 and 7.7 in control group, suggesting a significant resolution of symptoms (p < 0.01) in both groups but no significant difference between the two groups. UAE is effective for uttering fibroids showing high SI on T2WI. The mean volume reduction rate of the predominant fibroids three months after UAE was greater in the T2 high group than in the control group.

  13. Uterine Artery Embolization for Symptomatic Fibroids with High Signal Intensity on T2-Weighted MR Imaging

    International Nuclear Information System (INIS)

    Chang, Suyon; Kim, Man Deuk; Lee, Myung Su; Lee, Mu Sook; Park, Sung Il; Won, Jong Yun; Lee, Do Yun; Lee, Kwang Hun

    2012-01-01

    To evaluate the effectiveness of uterine artery embolization (UAE) for treating symptomatic fibroids with high signal intensity (SI) on magnetic resonance (MR) T2-weighted imaging (T2WI). A total of 537 cases, consisting of 14 patients with high SI fibroids on T2WI (T2 high group), were retrospectively included and compared with 28 randomly selected patients with low SI fibroids on T2WI (control group). High SI of a predominant fibroid on T2WI was defined as having the same or higher SI than the myometrium. Patient ages ranged from 28 to 52 years (mean, 38.1 years). All patients underwent MRI before and after UAE. Predominant fibroid and uterine volumes were calculated with MR images. Symptom status in terms of menorrhagia and dysmenorrhea was scored on a scale of 0-10, with 0 being no symptoms and 10 being the baseline, or initial symptoms. Of the patients in the T2 high group, 13 out of 14 (92.9%) patients demonstrated complete necrosis of the predominant fibroids. The mean volume reduction rates of the predominant fibroids in the T2 high group was 61.7% at three months after UAE, which was significantly higher than the volume reduction rates of 42.1% noted in the control group (p < 0.05). Changes in symptom scores for menorrhagia and dysmenorrhea after UAE (baseline score minus follow-up score) were 4.9 and 7.5 in T2 high group and they were 5.0 and 7.7 in control group, suggesting a significant resolution of symptoms (p < 0.01) in both groups but no significant difference between the two groups. UAE is effective for uttering fibroids showing high SI on T2WI. The mean volume reduction rate of the predominant fibroids three months after UAE was greater in the T2 high group than in the control group.

  14. 7T T₂*-weighted magnetic resonance imaging reveals cortical phase differences between early- and late-onset Alzheimer's disease.

    Science.gov (United States)

    van Rooden, Sanneke; Doan, Nhat Trung; Versluis, Maarten J; Goos, Jeroen D C; Webb, Andrew G; Oleksik, Ania M; van der Flier, Wiesje M; Scheltens, Philip; Barkhof, Frederik; Weverling-Rynsburger, Annelies W E; Blauw, Gerard Jan; Reiber, Johan H C; van Buchem, Mark A; Milles, Julien; van der Grond, Jeroen

    2015-01-01

    The aim of this study is to explore regional iron-related differences in the cerebral cortex, indicative of Alzheimer's disease pathology, between early- and late-onset Alzheimer's disease (EOAD, LOAD, respectively) patients using 7T magnetic resonance phase images. High-resolution T2(∗)-weighted scans were acquired in 12 EOAD patients and 17 LOAD patients with mild to moderate disease and 27 healthy elderly control subjects. Lobar peak-to-peak phase shifts and regional mean phase contrasts were computed. An increased peak-to-peak phase shift was found for all lobar regions in EOAD patients compared with LOAD patients (p < 0.05). Regional mean phase contrast in EOAD patients was higher than in LOAD patients in the superior medial and middle frontal gyrus, anterior and middle cingulate gyrus, postcentral gyrus, superior and inferior parietal gyrus, and precuneus (p ≤ 0.042). These data suggest that EOAD patients have an increased iron accumulation, possibly related to an increased amyloid deposition, in specific cortical regions as compared with LOAD patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Design of universal parallel-transmit refocusing kT -point pulses and application to 3D T2 -weighted imaging at 7T.

    Science.gov (United States)

    Gras, Vincent; Mauconduit, Franck; Vignaud, Alexandre; Amadon, Alexis; Le Bihan, Denis; Stöcker, Tony; Boulant, Nicolas

    2018-07-01

    T 2 -weighted sequences are particularly sensitive to the radiofrequency (RF) field inhomogeneity problem at ultra-high-field because of the errors accumulated by the imperfections of the train of refocusing pulses. As parallel transmission (pTx) has proved particularly useful to counteract RF heterogeneities, universal pulses were recently demonstrated to save precious time and computational efforts by skipping B 1 calibration and online RF pulse tailoring. Here, we report a universal RF pulse design for non-selective refocusing pulses to mitigate the RF inhomogeneity problem at 7T in turbo spin-echo sequences with variable flip angles. Average Hamiltonian theory was used to synthetize a single non-selective refocusing pulse with pTx while optimizing its scaling properties in the presence of static field offsets. The design was performed under explicit power and specific absorption rate constraints on a database of 10 subjects using a 8Tx-32Rx commercial coil at 7T. To validate the proposed design, the RF pulses were tested in simulation and applied in vivo on 5 additional test subjects. The root-mean-square rotation angle error (RA-NRMSE) evaluation and experimental data demonstrated great improvement with the proposed universal pulses (RA-NRMSE ∼8%) compared to the standard circularly polarized mode of excitation (RA-NRMSE ∼26%). This work further completes the spectrum of 3D universal pulses to mitigate RF field inhomogeneity throughout all 3D MRI sequences without any pTx calibration. The approach returns a single pulse that can be scaled to match the desired flip angle train, thereby increasing the modularity of the proposed plug and play approach. Magn Reson Med 80:53-65, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  16. Repeatability of magnetic resonance fingerprinting T1 and T2 estimates assessed using the ISMRM/NIST MRI system phantom.

    Science.gov (United States)

    Jiang, Yun; Ma, Dan; Keenan, Kathryn E; Stupic, Karl F; Gulani, Vikas; Griswold, Mark A

    2017-10-01

    The purpose of this study was to evaluate accuracy and repeatability of T 1 and T 2 estimates of a MR fingerprinting (MRF) method using the ISMRM/NIST MRI system phantom. The ISMRM/NIST MRI system phantom contains multiple compartments with standardized T 1 , T 2 , and proton density values. Conventional inversion-recovery spin echo and spin echo methods were used to characterize the T 1 and T 2 values in the phantom. The phantom was scanned using the MRF-FISP method over 34 consecutive days. The mean T 1 and T 2 values were compared with the values from the spin echo methods. The repeatability was characterized as the coefficient of variation of the measurements over 34 days. T 1 and T 2 values from MRF-FISP over 34 days showed a strong linear correlation with the measurements from the spin echo methods (R 2  = 0.999 for T 1 ; R 2  = 0.996 for T 2 ). The MRF estimates over the wide ranges of T 1 and T 2 values have less than 5% variation, except for the shortest T 2 relaxation times where the method still maintains less than 8% variation. MRF measurements of T 1 and T 2 are highly repeatable over time and across wide ranges of T 1 and T 2 values. Magn Reson Med 78:1452-1457, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  17. The Impact of Gd-Eob-Dtpa-Enhanced MR Cholangiography in Biliary Diseases: Comparison with T2-Weighted MR Cholangiopancreatography

    Directory of Open Access Journals (Sweden)

    Evrim Özmen

    2016-06-01

    Full Text Available Background: Contrast enhanced magnetic resonance cholangiography is a novel technique and promising method in demonstrating biliary tree anatomy and evaluating biliary disorders. However, to date, there are a limited number of studies that have focused on the impact of this technique. Aims: We aimed to evaluate the additional role of contrast enhanced MR cholangiography (MRC and compare contrast enhanced MRC with T2-weighted (w magnetic resonance cholangiopancreatography (MRCP in the diagnosis of biliary disorders. Study Design: Diagnostic accuracy study. Methods: The T2w-MRCP and contrast enhanced MRC sequences of 31 patients whose gold standard test results were available were scored visually for the existence of pathological findings with regard to any of the biliary diseases. Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA was used as the contrast agent. The correlation values were determined according to the statistical analysis made from those scores and the sensitivity, specificity and accuracy values of each sequence were detected as well. Results: We detected that the correlation values with gold standard methods of contrast enhanced MRC sequences were significantly higher than the ones of T2w-MRCP sequences. The correlation ratios of T2w-MRCP sequences were between 26 and 34%, while those for contrast enhanced MRC sequences were between 81 and 83% for the first reader and the correlation ratios of T2w-MRCP sequences were between 10 and 61%, whereas those of contrast enhanced MRC were between 79 and 81% for the second reader The mean sensitivity, specificity and accuracy values of T2w-MRCP sequences were 14.3-42.5%, 85-89.2% and 59.3-72.5%, respectively, while the mean sensitivity, specificity and accuracy values of contrast enhanced MRC sequences were 100%, 86.7% and 93.2-93.3%, respectively. Conclusion: We suggest that obtaining of contrast enhanced MRC sequences in addition to the T2w-MRCP can be useful in

  18. T2-weighted MRI-derived textural features reflect prostate cancer aggressiveness: preliminary results.

    Science.gov (United States)

    Nketiah, Gabriel; Elschot, Mattijs; Kim, Eugene; Teruel, Jose R; Scheenen, Tom W; Bathen, Tone F; Selnæs, Kirsten M

    2017-07-01

    To evaluate the diagnostic relevance of T2-weighted (T2W) MRI-derived textural features relative to quantitative physiological parameters derived from diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) MRI in Gleason score (GS) 3+4 and 4+3 prostate cancers. 3T multiparametric-MRI was performed on 23 prostate cancer patients prior to prostatectomy. Textural features [angular second moment (ASM), contrast, correlation, entropy], apparent diffusion coefficient (ADC), and DCE pharmacokinetic parameters (K trans and V e ) were calculated from index tumours delineated on the T2W, DW, and DCE images, respectively. The association between the textural features and prostatectomy GS and the MRI-derived parameters, and the utility of the parameters in differentiating between GS 3+4 and 4+3 prostate cancers were assessed statistically. ASM and entropy correlated significantly (p textural features correlated insignificantly with K trans and V e . GS 4+3 cancers had significantly lower ASM and higher entropy than 3+4 cancers, but insignificant differences in median ADC, K trans , and V e . The combined texture-MRI parameters yielded higher classification accuracy (91%) than the individual parameter sets. T2W MRI-derived textural features could serve as potential diagnostic markers, sensitive to the pathological differences in prostate cancers. • T2W MRI-derived textural features correlate significantly with Gleason score and ADC. • T2W MRI-derived textural features differentiate Gleason score 3+4 from 4+3 cancers. • T2W image textural features could augment tumour characterization.

  19. Contrast-enhanced MR imaging of metastatic brain tumor at 3 Tesla. Utility of T1-weighted SPACE compared with 2D spin echo and 3D gradient echo sequence

    International Nuclear Information System (INIS)

    Komada, Tomohiro; Naganawa, Shinji; Ogawa, Hiroshi

    2008-01-01

    We evaluated the newly developed whole-brain, isotropic, 3-dimensional turbo spin-echo imaging with variable flip angle echo train (SPACE) for contrast-enhanced T 1 -weighted imaging in detecting brain metastases at 3 tesla (T). Twenty-two patients with suspected brain metastases underwent postcontrast study with SPACE, magnetization-prepared rapid gradient-echo (MP-RAGE), and 2-dimensional T 1 -weighted spin echo (2D-SE) imaging at 3 T. We quantitatively compared SPACE, MP-RAGE, and 2D-SE images by using signal-to-noise ratios (SNRs) for gray matter (GM) and white matter (WM) and contrast-to-noise ratios (CNRs) for GM-to-WM, lesion-to-GM, and lesion-to-WM. Two blinded radiologists evaluated the detection of brain metastases by segment-by-segment analysis and continuously-distributed test. The CNR between GM and WM was significantly higher on MP-RAGE images than on SPACE images (P 1 -weighted imaging. (author)

  20. Characterization of D-maltose as a T2 -exchange contrast agent for dynamic contrast-enhanced MRI.

    Science.gov (United States)

    Goldenberg, Joshua M; Pagel, Mark D; Cárdenas-Rodríguez, Julio

    2018-09-01

    We sought to investigate the potential of D-maltose, D-sorbitol, and D-mannitol as T 2 exchange magnetic resonance imaging (MRI) contrast agents. We also sought to compare the in vivo pharmacokinetics of D-maltose with D-glucose with dynamic contrast enhancement (DCE) MRI. T 1 and T 2 relaxation time constants of the saccharides were measured using eight pH values and nine concentrations. The effect of echo spacing in a multiecho acquisition sequence used for the T 2 measurement was evaluated for all samples. Finally, performances of D-maltose and D-glucose during T 2 -weighted DCE-MRI were compared in vivo. Estimated T 2 relaxivities (r 2 ) of D-glucose and D-maltose were highly and nonlinearly dependent on pH and echo spacing, reaching their maximum at pH = 7.0 (∼0.08 mM -1 s -1 ). The r 2 values of D-sorbitol and D-mannitol were estimated to be ∼0.02 mM -1 s -1 and were invariant to pH and echo spacing for pH ≤7.0. The change in T 2 in tumor and muscle tissues remained constant after administration of D-maltose, whereas the change in T 2 decreased in tumor and muscle after administration of D-glucose. Therefore, D-maltose has a longer time window for T 2 -weighted DCE-MRI in tumors. We have demonstrated that D-maltose can be used as a T 2 exchange MRI contrast agent. The larger, sustained T 2 -weighted contrast from D-maltose relative to D-glucose has practical advantages for tumor diagnoses during T 2 -weighted DCE-MRI. Magn Reson Med 80:1158-1164, 2018. © 2018 International Society for Magnetic Resonance in Medicine. © 2018 International Society for Magnetic Resonance in Medicine.

  1. Prospects for 10T accelerator dipole magnets

    International Nuclear Information System (INIS)

    Taylor, C.E.; Meuser, R.B.

    1981-03-01

    A next-generation major accelerator will require the highest possible field to minimize the circumference; however, there have been no proven designs for suitable magnets with fields substantially higher than 5T. A number of successful 4 to 5T dipole magnets have been built in recent years; these have involved long and difficult development projects. The 3'' bore 4.25T magnets for the Doubler are being produced by the hundreds at Fermilab, and a number of prototypes of the 5.2'' bore 5T ISABELLE magnets have been built. Successful short, approx. 5T models have been made at SACLAY, KEK, and Serpukhov, and a number of model magnets with lower fields have been built at many laboratories. Field uniformity achieved in these magnets is about ΔB/B approx. = 10 -3 . 10T magnets with higher field uniformity will be a challenging development task. The general problems of high-field (10T) magnets are discussed in terms of superconductor performance and mechanical limitations

  2. Magnetotransport properties in the magnetic phase of BaFe2 -xTxAs2 (T =Co ,Ni ) : A magnetic excitations approach

    Science.gov (United States)

    Peña, J. P.; Piva, M. M.; Rosa, P. F. S.; Pagliuso, P. G.; Adriano, C.; Grant, T.; Fisk, Z.; Baggio-Saitovitch, E.; Pureur, P.

    2018-03-01

    Because of their complex Fermi surfaces, the identification of the physical phenomena contributing to electronic scattering in the Fe-based superconductors is a difficult task. Here, we report on the electrical resistivity, magnetoresistance, and Hall effect in two series of BaFe2 -xTxAs2 (T =Co ,Ni ) crystals with different values of x . The T contents were chosen so that the majority of the investigated samples present an intermediate magnetically ordered state and a superconducting ground state. We interpret the obtained results in terms of scattering of charge carriers by magnetic excitations instead of describing them as resulting uniquely from effects related to multiple-band conduction. Our samples are single crystals from the structural point of view and their overall magnetotransport properties are dominated by a single magnetic state.

  3. Reduction of superoxide dismutase activity correlates with visualization of edema by T2-weighted MR imaging in focal ischemic rat brain

    International Nuclear Information System (INIS)

    Imaizumi, Shigeki; Chang, LeeHong; Cohen, Yoram; Chan, P.H.; Weinstein, P.R.; James, T.L.; Yoshimoto, Takashi.

    1994-01-01

    This study investigated the correlation between in vivo serial T 2 -weighted magnetic resonance (MR) imaging and changes in superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, and water, sodium ion (Na + ), and potassium ion (K + ) contents measured in vitro using rat brain following right middle cerebral artery occlusion in conjunction with bilateral common carotid artery (CCA) occlusion. One hour later the left CCA was released. Serial MR images showed edema developed from the outer cortex towards the center. The T 2 signal intensity of the injured right cortex increased with time compared to that of the contralateral cortex. Increased Na + and water and decreased K + contents occurred in the injured cortex, indicating that serial T 2 -weighted MR imaging reflects the changes in water content and Na + and K + concentrations determined by biochemical techniques. GSH-Px activity was little changed. Total SOD in the injured cortex decreased 1 hour after ischemia and remained low throughout the experiment. In contrast, SOD activity in the noninfarcted left cortex also decreased after 1 hour but returned to normal after 2 hours of ischemia. Our results suggest that oxygen free radicals are important in developing ischemic brain edema and cerebral infarction. (author)

  4. MR urography (MRU of non-dilated ureter with diuretic administration: Static fluid 2D FSE T2-weighted versus 3D gadolinium T1-weighted GE excretory MR

    Directory of Open Access Journals (Sweden)

    C. Roy

    2014-01-01

    Conclusion: T2-weighted MRU with multiple orientations and diuretic is sufficient to identify the non-dilated ureter. It offers information on ureteral peristaltism. It can be suggested that this sequence is able to detect an initial obstruction before hydronephrosis occurs.

  5. Visualization of cranial nerves I-XII: value of 3D CISS and T2-weighted FSE sequences

    Energy Technology Data Exchange (ETDEWEB)

    Yousry, I.; Camelio, S.; Wiesmann, M.; Brueckmann, H.; Yousry, T.A. [Department of Neuroradiology, Klinikum Grosshadern, Ludwig-Maximilians University, Marchioninistrasse 15, D-81377 Munich (Germany); Schmid, U.D. [Neurosurgical Unit, Klinik im Park, 8000 Zurich (Switzerland); Horsfield, M.A. [Department of Medical Physics, University of Leicester, Leicester LE1 5WW (United Kingdom)

    2000-07-01

    The aim of this study was to evaluate the sensitivity of the three-dimensional constructive interference of steady state (3D CISS) sequence (slice thickness 0.7 mm) and that of the T2-weighted fast spin echo (T2-weighted FSE) sequence (slice thickness 3 mm) for the visualization of all cranial nerves in their cisternal course. Twenty healthy volunteers were examined using the T2-weighted FSE and the 3D CISS sequences. Three observers evaluated independently the cranial nerves NI-NXII in their cisternal course. The rates for successful visualization of each nerve for 3D CISS (and for T2-weighted FSE in parentheses) were as follows: NI, NII, NV, NVII, NVIII 40 of 40 (40 of 40), NIII 40 of 40 (18 of 40), NIV 19 of 40 (3 of 40), NVI 39 of 40 (5 of 40), NIX, X, XI 40 of 40 (29 of 40), and NXII 40 of 40 (4 of 40). Most of the cranial nerves can be reliably assessed when using the 3D CISS and the T2-weighted FSE sequences. Increasing the spatial resolution when using the 3D CISS sequence increases the reliability of the identification of the cranial nerves NIII-NXII. (orig.)

  6. Visualization of cranial nerves I-XII: value of 3D CISS and T2-weighted FSE sequences

    International Nuclear Information System (INIS)

    Yousry, I.; Camelio, S.; Wiesmann, M.; Brueckmann, H.; Yousry, T.A.; Schmid, U.D.; Horsfield, M.A.

    2000-01-01

    The aim of this study was to evaluate the sensitivity of the three-dimensional constructive interference of steady state (3D CISS) sequence (slice thickness 0.7 mm) and that of the T2-weighted fast spin echo (T2-weighted FSE) sequence (slice thickness 3 mm) for the visualization of all cranial nerves in their cisternal course. Twenty healthy volunteers were examined using the T2-weighted FSE and the 3D CISS sequences. Three observers evaluated independently the cranial nerves NI-NXII in their cisternal course. The rates for successful visualization of each nerve for 3D CISS (and for T2-weighted FSE in parentheses) were as follows: NI, NII, NV, NVII, NVIII 40 of 40 (40 of 40), NIII 40 of 40 (18 of 40), NIV 19 of 40 (3 of 40), NVI 39 of 40 (5 of 40), NIX, X, XI 40 of 40 (29 of 40), and NXII 40 of 40 (4 of 40). Most of the cranial nerves can be reliably assessed when using the 3D CISS and the T2-weighted FSE sequences. Increasing the spatial resolution when using the 3D CISS sequence increases the reliability of the identification of the cranial nerves NIII-NXII. (orig.)

  7. Fast T1- and T2-weighted pulmonary MR-imaging in patients with bronchial carcinoma

    International Nuclear Information System (INIS)

    Both, M.; Schultze, J.; Reuter, M.; Bewig, B.; Hubner, R.; Bobis, I.; Noth, R.; Heller, M.; Biederer, J.

    2005-01-01

    Purpose: A prospective study to evaluate the diagnostic potential and limitations of three fast MRI sequences in patients with bronchial carcinoma based on the comparison with spiral CT. Material and methods: Three fast chest MRI sequences from 20 patients with central or peripheral bronchial carcinoma were evaluated by two observers for relation of tumour to adjacent structures, lymph node enlargement, additional pulmonary lesions and artefacts. The information from MR-imaging was compared with the results from spiral CT. MRI comprised a T1-3D-GRE breath-hold examination ('VIBE', TR/TE 4.5/1.9 ms, flip-angle 12 deg., matrix 502 x 512, 2.5 mm coronal slices), a breath-hold, T2-HASTE sequence (TR/TE 2000/43 ms, matrix 192 x 256, 10 mm coronal slices) and a respiration-triggered T2-TSE sequence (TR/TE 3000-6000/120 ms, matrix 270 x 512, 6 mm transverse slices). The FOV was adapted individually (380-480 mm). Results: The presence of the primary bronchial carcinoma and infiltration of thoracic structures by tumour tissue could be demonstrated by all sequences. VIBE sequence was more suitable for detecting small pulmonary nodules than the other MRI examinations, but compared to CT still 20% of these lesions were missed. Contrary to VIBE and T2-weighted TSE scans, HASTE sequence was limited in imaging mediastinal lymph nodes due to missing relevant findings in 2/20 patients. HASTE images significantly provided the lowest rate of artefacts in imaging lung parenchyma (P < 0.001 in peripheral parenchyma), but spatial resolution was limited in this sequence. Concerning the differentiation between tumour and adjacent atelectasis (n = 8), T2-weighted TSE imaging was superior to CT and VIBE in all cases and to HASTE sequence in 4/8 patients. Conclusion: The combination of VIBE and HASTE sequence allows for an adequate imaging of thoracic processes in patients with bronchial carcinoma, limited only in visualizing small pulmonary nodules. To obtain more detail resolution and to

  8. Temporal and spatial characteristics of the area at risk investigated using computed tomography and T1-weighted magnetic resonance imaging

    DEFF Research Database (Denmark)

    van der Pals, Jesper; Hammer-Hansen, Sophia; Nielles-Vallespin, Sonia

    2015-01-01

    AIMS: Cardiovascular magnetic resonance (CMR) imaging can measure the myocardial area at risk (AAR), but the technique has received criticism for inadequate validation. CMR commonly depicts an AAR that is wider than the infarct, which in turn would require a lateral perfusion gradient within...... and fluorescent microparticle pathology were used to investigate the AAR in a canine model (n = 10) of ischaemia and reperfusion. AAR size by CMR correlated well with CT (R(2) = 0.80), microsphere blood flow (R(2) = 0.80), and pathology (R(2) = 0.74) with good limits of agreement [-0.79 ± 4.02% of the left.......05 ± 0.02 mL/g/min, lateral vs. core, P = 0.001). The transmural extent of MI was lower in the lateral portion of the AAR than the core (28.2 ± 10.2 vs. 17.4 ± 8.4% of the wall, P = 0.001). CONCLUSION: T1-weighted CMR accurately quantifies size of the AAR with excellent agreement compared with three...

  9. High signal in the spinal cord on T2-weighted images in rapidly progressive tropical spastic paraparesis

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, M.; Hara, A.; Murakami, T.; Ando, Y.; Uyama, E.; Mita, S.; Uchino, M. [Kumamoto Univ. (Japan). School of Medicine; Yamashita, T. [Kumamoto Univ. (Japan). School of Medicine; Dept. of Neurology, Kumamoto Univ. (Japan)

    2001-03-01

    We report a 59-year-old woman with human T-cell lymphotrophic virus type-I (HTLV-I) associated myelopathy/tropical spastic paraparesis who showed high signal in the cervical and thoracic spinal cord on T2-weighted and contrast enhancement on T1-weighted images. (orig.)

  10. Focal Pancreatitis Mimicking Pancreatic Mass: Magnetic Resonance Imaging (MRI)/Magnetic Resonance Cholangiopancreatography (MRCP) Findings Including Diffusion-Weighted MRI

    International Nuclear Information System (INIS)

    Momtahen, A.J.; Balci, N.C.; Alkaade, S.; Akduman, E.I.; Burton, F.R.

    2008-01-01

    Background: Focal pancreatitis (FP) is a confined inflammation that mimics a pancreatic mass. Its imaging diagnosis is important to avoid unnecessary procedures. Purpose: To describe the spectrum of magnetic resonance imaging (MRI)/magnetic resonance cholangiopancreatography (MRCP) and diffusion-weighted MRI (DWI) findings of focal pancreatitis mimicking pancreatic masses. Material and Methods: Findings of MRI/MRCP including DWI with a b value of 0 and 600 s/mm2 in 14 patients with pancreatic masses on MRI were retrospectively reviewed and compared to normal pancreas in 14 patients as a control group. Results: FP revealed hypointense signal intensity (SI) (3/14), hypo- to isointense SI (7/14), or isointense SI (4/14) on T1-weighted images, and hypointense SI (1/14), isointense SI (5/14), iso- to hyperintense SI (7/14), or hyperintense SI (1/14) on T2-weighted images compared to remaining pancreas (RP). MRCP images revealed dilatation of the common bile duct (CBD) and main pancreatic duct (MPD) (5/14), dilatation of the MPD only (3/14), dilatation of the CBD only (3/14), and normal MPD and CBD (3/14). Both FP and RP revealed three types of time-signal intensity curves: 1) rapid rise to a peak, with a rapid decline (FP=2, RP=4), 2) slow rise to a peak, followed by a slow decline (FP=5, RP=4), and 3) slower rise to a peak, with a slow decline or plateau (FP=7, RP=6). Mean apparent diffusion coefficient (ADC) values for FP and RP were 2.09±0.18 and 2.03±0.2x10 -3 mm 2 /s, respectively. ADC values of FP and RP revealed no significant difference. Conclusion: The spectrum of imaging findings of focal pancreatitis on MRI/MRCP including DWI was described. Findings of FP were not distinctive as compared to the remaining pancreas

  11. A 2-Tesla active shield magnet for whole body imaging and spectroscopy

    International Nuclear Information System (INIS)

    Davies, F.J.; Elliott, R.T.; Hawksworth, D.G.

    1991-01-01

    This paper reports on the development and testing of a 2T superconducting Active Shield magnet, with a 0.99m diameter warm bore for whole-body Magnetic Resonance Imaging (MRI) and spectroscopy. The magnet and cryostat were designed to meet the same performance standards as existing MRI magnets, but with the volume of the stray field region reduced to less than 4% of that for an unshielded magnet. The 0.5 mT stray field contour is within 5m axially and 3m radially of the magnet center. The system weight is only 14 tonnes

  12. MR imaging of intracerebral hemorrhage lesions: Comparison of 2.0 T and 0.5 T images

    International Nuclear Information System (INIS)

    Han, Moon Hee; Chang, Kee Hyun

    1990-01-01

    Seventeen patients with intracerebral hemorrhage lesions were examined with magnetic resonance imaging at both 2.0 T and 0.5 T, in order to evaluate the capability of detecting and characterizing the hemorrhagic lesions at each field strength and to compare the signal intensities of the hemorrhages between both field strengths. The intervals between two imagings were within 2 hours in all patients except for 4 patients with subacute hematoma and occult cerebrovascular malformations in whom the intervals were 1 to 4 days. At each field strength, both T1 and T2-weighted spin echo(SE) images were obtained in all patients. All the hemorrhagic lesions were readily detected and characterized as hemorrhagic lesions at 2.0 T, whereas one lesion of chronic hemorrhage was not detected, and three lesions(one acute hemorrhage, one chronic hemorrhage and one occult cerebrovascular malformation) could not be characterized as hemorrhagic lesions at 0.5 T. There were statistically significant differences in signal intensity of the hematomas between 2.0 T and 0.5 T on proton density-weighted and T2-weighted images in cases of acute intracerebral hematomas: the hematomas seen as low intensity at 2.0 T appeared iso-or slightly high at 0.5 T. In conclusion, the intracerebral hematomas may be difficult to detect and to characterize with SE technique at 0.5 T, and then the gradient echo technique may be useful at 0.5 T

  13. Cerebral abnormalities: use of calculated T1 and T2 magnetic resonance images for diagnosis

    International Nuclear Information System (INIS)

    Mills, C.M.; Crooks, L.E.; Kaufman, L.; Brant-Zawadzki, M.

    1984-01-01

    The potential clinical importance of T1 and T2 relaxation times in distinguishing normal and pathologic tissue with magnetic resonance (MR) is discussed and clinical examples of cerebral abnormalities are given. Five patients with cerebral infarction, 15 with multiple sclerosis, two with Wilson disease, and four with tumors were imaged. Hemorrhagic and ischemic cerebrovascular accidents were distinguished using the spin echo technique. In the patients with multiple sclerosis, lesions had prolonged T1 and T2 times, but the definition of plaque was limited by spatial resolution. No abnormalities in signal intensity were seen in the patient with Wilson disease who was no longer severly disabled; abnormal increased signal intensity in the basal ganglia was found in the second patient with Wilson disease. Four tumors produced abnormal T1 and T2 relaxation times but these values alone were not sufficient for tumor characterization

  14. Improved supercapacitor performance of MnO2-electrospun carbon nanofibers electrodes by mT magnetic field

    Science.gov (United States)

    Zeng, Zheng; Liu, Yiyang; Zhang, Wendi; Chevva, Harish; Wei, Jianjun

    2017-08-01

    This work reports on a finding of mT magnetic field induced energy storage enhancement of MnO2-based supercapacitance electrodes (magneto-supercapacitor). Electrodes with MnO2 electrochemically deposited at electrospun carbon nanofibers (ECNFs) film are studied by cyclic voltammetry (CV), galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), and life cycle stability tests in the presence/absence of milli-Tesla (mT) magnetic fields derived by Helmholtz coils. In the presence of a 1.34 mT magnetic field, MnO2/ECNFs shows a magneto-enhanced capacitance of 141.7 F g-1 vs. 119.2 F g-1 (∼19% increase) with absence of magnetic field at a voltage sweeping rate of 5 mV s-1. The mechanism of the magneto-supercapacitance is discussed and found that the magnetic susceptibility of the MnO2 significantly improves the electron transfer of a pseudo-redox reaction of Mn(IV)/Mn(III) at the electrode, along with the magnetic field induced impedance effect, which may greatly enhance the interface charge density, facilitate electrolyte transportation, and improve the efficiency of cation intercalation/de-intercalation of the pseudocapacitor under mT-magnetic field exposure, resulting in enhancement of energy storage capacitance and longer charge/discharge time of the MnO2/ECNFs electrode without sacrificing its life cycle stability.

  15. Developmental patterns of fetal fat and corresponding signal on T1-weighted magnetic resonance imaging

    International Nuclear Information System (INIS)

    Blondiaux, Eleonore; Chougar, Lydia; Ducou le Pointe, Hubert; Garel, Catherine; Gelot, Antoinette; Valence, Stephanie; Audureau, Etienne; Jouannic, Jean-Marie; Dhombres, Ferdinand

    2018-01-01

    Evaluation of subcutaneous fetal fat layer thickness on T1-weighted sequences can be used to predict birth weight. Little is known about normal MR signal patterns of subcutaneous tissue throughout pregnancy. To establish developmental patterns of subcutaneous fetal fat signal on T1-weighted sequences during the 2nd and 3rd trimesters. We retrospectively examined T1-weighted images of 110 fetal MRI scans. We measured signal intensity of subcutaneous fat on thighs, buttocks, trunk, nuchal region, chin and scalp. We then calculated the ratios of the obtained values with fetal muscle, amnios and maternal fat signal, and compared the results with those of immunohistochemical examination of adipose tissue extracted from the abdominal wall of fetuses as part of standard autopsy protocol. We included 60 MRI scans in fetuses without intra-uterine growth restriction or macrosomia of non-diabetic mothers (range 23-37 weeks of gestation). Fat T1 intensity of all anatomical regions was low in all fetuses before 26 weeks of gestation. It became more hyperintense with increasing gestational age, in the following order: chin and nuchal region, then buttocks, thighs and trunk, and eventually the scalp at 33 weeks of gestation. After 33 weeks of gestation, all fetal subcutaneous tissues demonstrated overall hyperintense signal. This progression followed the conversion at immunohistochemistry of fetal adipose tissue composition from predominant brown to white adipose cells in 19 fetuses (19-41 weeks of gestation). Between 26 weeks and 33 weeks of gestation, subcutaneous fetal fat signal changed in an orderly pattern from chin to buttocks and scalp. This may reflect the conversion from predominant brown to white adipose tissues in subcutaneous fetal fat. (orig.)

  16. Feasibility of ultrasound-guided high intensity focused ultrasound ablating uterine fibroids with hyperintense on T2-weighted MR imaging

    International Nuclear Information System (INIS)

    Zhao, Wen-Peng; Chen, Jin-Yun; Zhang, Lian; Li, Quan; Qin, Juan

    2013-01-01

    Purpose: To retrospectively investigate whether uterine fibroids with hyperintense on pretreatment T2-weighted magnetic resonance imaging (MRI) could be treated with ultrasound-guided high intensity focused ultrasound (USgHIFU). Materials and methods: 282 patients with 282 symptomatic uterine fibroids who underwent USgHIFU treatment were retrospectively analyzed. Based on the signal intensity of T2-weighted MRI, uterine fibroids were classified as hypointense, isointense and hyperintense. Hyperintense fibroids were subjectively further subdivided into heterogeneous hyperintense, slightly homogeneous hyperintense and markedly homogeneous hyperintense based on the signal intensity of fibroid relative to myometrium and endometrium on T2-weighted MRI. Enhanced MRI was performed within one month after HIFU treatment. Non-perfused volume (NPV, indicative of successful ablation) ratio, treatment time, treatment efficiency, energy effect ratio and adverse events were recorded. Results: The median volume of uterine fibroids was 70.3 cm 3 (interquartile range, 41.1–132.5 cm 3 ). The average NPV ratio, defined as non-perfused volume divided by the fibroid volume after HIFU treatment, was 76.8 ± 19.0% (range, 0–100%) in the 282 patients. It was 86.3 ± 11.9% (range, 40.9–100.0%) in the group with hypointense fibroids, 77.1 ± 16.5% (range, 32.2–100.0%) in isointense fibroids, and 67.6 ± 23.9% (range, 0–100.0%) in hyperintense fibroids. The lowest NPV ratio, lowest treatment efficiency, more treatment time, more sonication energy and pain scores were observed in the slightly homogeneous hyperintense fibroids, and the NPV ratio was 55.8 ± 26.7% (range, 0–83.9%) in this subgroup. Conclusion: Based on our results, the heterogeneous and markedly homogeneous hyperintense fibroids were suitable for USgHIFU, and only the slightly homogeneous hyperintense fibroids should be excluded

  17. Liver Lobe Based Multi-Echo Gradient Recalled Echo T2*-Weighted Imaging in Chronic Hepatitis B-Related Cirrhosis: Association with the Presence and Child-Pugh Class of Cirrhosis.

    Directory of Open Access Journals (Sweden)

    Dan Wang

    Full Text Available To investigate whether liver lobe based T2* values measured on gradient recalled echo T2*-weighted imaging are associated with the presence and Child-Pugh class of hepatitis B-related cirrhosis.Fifty-six patients with hepatitis B-related cirrhosis and 23 healthy control individuals were enrolled in this study and underwent upper abdominal T2*-weighted magnetic resonance imaging. T2* values of the left lateral lobe (LLL, left medial lobe (LML, right lobe (RL and caudate lobe (CL were measured on T2*-weighted imaging. Statistical analyses were performed to determine the association between liver lobe based T2* values and the presence and Child-Pugh class of cirrhosis.The T2* values of the LLL, LML and RL decreased with the progression of cirrhosis from Child-Pugh class A to C (r = -0.231, -0.223, and -0.395, respectively; all P 0.05. To a certain extent, Mann-Whitney U tests with Bonferroni correction for multigroup comparisons showed that the T2* values of the LLL, LML and RL could distinguish cirrhotic liver from healthy liver (all P 0.05. Receiver operating characteristic analysis demonstrated that the T2* value of the RL could best distinguish cirrhosis from healthy liver, with an area under the receiver operating characteristic curve (AUC of 0.713 among T2* values of the liver lobes, and that only the T2* value of the RL could distinguish Child-Pugh class C from A-B, with an AUC of 0.697 (all P < 0.05.The T2* value of the RL can be associated with the presence and Child-Pugh class of hepatitis B-related cirrhosis.

  18. Rapid Evaluation of Platelet Function With T2 Magnetic Resonance

    Science.gov (United States)

    Cuker, Adam; Husseinzadeh, Holleh; Lebedeva, Tatiana; Marturano, Joseph E.; Massefski, Walter; Lowery, Thomas J.; Lambert, Michele P.; Abrams, Charles S.; Weisel, John W.

    2016-01-01

    Objectives: The clinical diagnosis of qualitative platelet disorders (QPDs) based on light transmission aggregometry (LTA) requires significant blood volume, time, and expertise, all of which can be barriers to utilization in some populations and settings. Our objective was to develop a more rapid assay of platelet function by measuring platelet-mediated clot contraction in small volumes (35 µL) of whole blood using T2 magnetic resonance (T2MR). Methods: We established normal ranges for platelet-mediated clot contraction using T2MR, used these ranges to study patients with known platelet dysfunction, and then evaluated agreement between T2MR and LTA with arachidonic acid, adenosine diphosphate, epinephrine, and thrombin receptor activator peptide. Results: Blood from 21 healthy donors was studied. T2MR showed 100% agreement with LTA with each of the four agonists and their cognate inhibitors tested. T2MR successfully detected abnormalities in each of seven patients with known QPDs, with the exception of one patient with a novel mutation leading to Hermansky-Pudlak syndrome. T2MR appeared to detect platelet function at similar or lower platelet counts than LTA. Conclusions: T2MR may provide a clinically useful approach to diagnose QPDs using small volumes of whole blood, while also providing new insight into platelet biology not evident using plasma-based platelet aggregation tests. PMID:28028118

  19. Feasibility of diffusion-weighted magnetic resonance imaging in patients with juvenile idiopathic arthritis on 1.0-T open-bore MRI

    Energy Technology Data Exchange (ETDEWEB)

    Barendregt, Anouk M.; Nusman, Charlotte M. [University of Amsterdam, Department of Radiology, Academic Medical Center, Amsterdam (Netherlands); University of Amsterdam, Department of Pediatric Hematology, Immunology, Rheumatology and Infectious Disease, Emma Children' s Hospital AMC, Amsterdam (Netherlands); Hemke, Robert; Lavini, Cristina; Maas, Mario [University of Amsterdam, Department of Radiology, Academic Medical Center, Amsterdam (Netherlands); Amiras, Dimitri [Imperial College Healthcare NHS Trust, Radiology Department, St. Mary' s Hospital, Paddington, London (United Kingdom); Kuijpers, Taco W. [University of Amsterdam, Department of Pediatric Hematology, Immunology, Rheumatology and Infectious Disease, Emma Children' s Hospital AMC, Amsterdam (Netherlands)

    2015-12-15

    To evaluate the feasibility of non-invasive diffusion-weighted imaging (DWI) of the knee of children with juvenile idiopathic arthritis (JIA) and, further, to analyze the apparent diffusion coefficient (ADC) levels to distinguish synovium from effusion. Standard magnetic resonance imaging of the knee including post-contrast imaging was obtained in eight patients (mean age, 12 years 8 months, five females) using an open-bore magnetic resonance imaging system (1.0 T). In addition, axially acquired echo-planar DWI datasets (b-values 0, 50, and 600) were prospectively obtained and the diffusion images were post-processed into ADC{sub 50-600} maps. Two independent observers selected a region of interest (ROI) for both synovium and effusion using aligned post-contrast images as landmarks. Mann-Whitney U test was performed to compare ADC synovium and ADC effusion. DWI was successfully obtained in all patients. When data of both observers was combined, ADC synovium was lower than ADC effusion in the ROI in seven out of eight patients (median, 1.92 x 10{sup -3} mm{sup 2}/s vs. 2.40 x 10{sup -3} mm{sup 2}/s, p = 0.006, respectively). Similar results were obtained when the two observers were analyzed separately (observer 1: p = 0.006, observer 2: p = 0.04). In this pilot study, on a patient-friendly 1.0-T open-bore MRI, we demonstrated that DWI may potentially be a feasible non-invasive imaging technique in children with JIA. We could differentiate synovium from effusion in seven out of eight patients based on the ADC of synovium and effusion. However, to select synovium and effusion on DWI, post-contrast images were still a necessity. (orig.)

  20. A study on magnetic relaxation times of various organs and body fluids using superconducting magnetic resonance imaging system part I: measurement of relative signal intensity and T2 relaxation time in various portions of brain and cerebrospinal fluid

    International Nuclear Information System (INIS)

    Chang, Kee Hyun; Lee, Ghi Jai; Han, Moon Hee; Kim, Jae Ho; Han, Man Chang; Kim, Chu Wan

    1988-01-01

    This study was undertake to determine if routine clinical magnetic resonance imaging sequences using only two different repetition times (TRs) and with only two sequential echo times (TEs) can be used to measure reproducible relative signal intensity and T2 relaxation time for normal brain tissues and cerebrospinal fluid using a 2.0T superconducting system. In 47 patients 6 different anatomic sites were measured. For each anatomic location, the mean and standard deviation of these values were determined. On T1-weighted (SE 500msec/30msec) images, in globus pallidus and thalamus, of the CSF, cortical gray matter and retrobulbar fat tissue varied more, with a standard deviation of 11-14% on T1-weighted images. On T2-weighted (SE 3000msec/30msec and 3000msec/80msec) images, the relative signal intensity of all anatomic regions varied more than on T1-weighted images. The standard deviation of T2 relaxation times also varied from 10% (fat tissue) to 18% (CSF). These variations might be due to partial volume averaging, signal alteration of CSF secondary to CSF pulsatile motion, etc. Knowing that relative signal intensity and T2 relaxation times calculated from routine imaging sequences are reproducible in only limited area, these normal ranges can be used to investigate changes occurring in disease states of the limited regions.

  1. Evaluation of patellar chondromalacia with MR: comparison between T2-weighted FSE SPIR and GE MTC.

    Science.gov (United States)

    Macarini, Luca; Perrone, Alessandra; Murrone, Mario; Marini, Stefania; Stefanelli, Michele

    2004-09-01

    To compare two different MR sequences to tissue signal suppression in the study of patellar cartilage abnormalities. We examined 26 patients with magnetic resonance (MR) imaging: sequences included spectral presaturation with inversion recovery (SPIR), with fat suppression and T2-weighted images, magnetization transfer contrast (MTC) sequences, T1-weighted and T2-weighted spin-echo sequences. All patients underwent conventional knee arthroscopy and in all patients a hyaline cartilage lesion was assessed in three articular zones: the patellar medial facet, the lateral facet and the patellar crista. Was assessed 78 articular facets. The lesions were classified using a standard arthroscopic grading system adapted to MR imaging: normal cartilage that corresponds to the grade 0 according to the Noyes grading system, low grade lesions that correspond to the grade I e IIa and high grade lesions that correspond to grades IIb and III. The arthroscopic results were compared with MR images. We assessed the MR diagnostic accuracy, sensitivity, specificity and MR positive predictive value and negative predictive value of the two sequences taking into consideration total lesions, and high-grade and low grade lesions separately. Twenty-four low grade lesions (16 grade I e 8 grade IIa) and 18 high grade lesions (10 grade IIb e 8 grade III) were diagnosed by arthroscopy. Regarding low grade and high-grade lesions together, the accuracy was 77% for MTC sequences and 90% for SPIR sequences. In identifying low-grade lesions, the sensitivity was 88% for SPIR sequence and 42% for MTC sequences. Specificity for the detection of all lesions was 89% for the SPIR sequences and 94% for the MTC sequences. The SPIR sequence visualised water content abnormalities in degenerating cartilage, which are representative of low-grade lesions. The sensitivity of the sequence enabled us to obtain improved contrast for detecting cartilage surface irregularities. The MTC sequences allowed us to grade high

  2. Magnetic-Field-Enhanced Incommensurate Magnetic Order in the Underdoped High-Temperature Superconductor YBa2Cu3O6.45

    DEFF Research Database (Denmark)

    Haug, D.; Hinkov, V.; Suchaneck, A.

    2009-01-01

    We present a neutron-scattering study of the static and dynamic spin correlations in the underdoped high-temperature superconductor YBa2Cu3O6.45 in magnetic fields up to 15 T. The field strongly enhances static incommensurate magnetic order at low temperatures and induces a spectral-weight shift...

  3. Observation of exchange of micropore water in cement pastes by two-dimensional T(2)-T(2) nuclear magnetic resonance relaxometry.

    Science.gov (United States)

    Monteilhet, L; Korb, J-P; Mitchell, J; McDonald, P J

    2006-12-01

    The first detailed analysis of the two-dimensional (2D) NMR T(2)-T(2) exchange experiment with a period of magnetization storage between the two T(2) relaxation encoding periods (T(2)-store-T(2)) is presented. It is shown that this experiment has certain advantages over the T(1)-T(2) variant for the quantization of chemical exchange. New T(2)-store-T(2) 2D 1H NMR spectra of the pore water within white cement paste are presented. Based on these spectra, the exchange rate of water between the two smallest porosity reservoirs is estimated for the first time. It is found to be of the order of 5 ms{-1}. Further, a careful estimate of the pore sizes of these reservoirs is made. They are found to be of the order of 1.4 nm and 10-30 nm , respectively. A discussion of the results is developed in terms of possible calcium silicate hydrate products. A water diffusion coefficient inferred from the exchange rate and the cement particle size is found to compare favorably with the results of molecular-dynamics simulations to be found in the literature.

  4. T2-weighted MRI-derived textural features reflect prostate cancer aggressiveness: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Nketiah, Gabriel; Elschot, Mattijs; Kim, Eugene; Teruel, Jose R. [NTNU, Norwegian University of Science and Technology, Department of Circulation and Medical Imaging, Faculty of Medicine, Trondheim (Norway); Scheenen, Tom W. [Radboud University Medical Center, Department of Radiology and Nuclear Medicine, Nijmegen (Netherlands); Bathen, Tone F.; Selnaes, Kirsten M. [NTNU, Norwegian University of Science and Technology, Department of Circulation and Medical Imaging, Faculty of Medicine, Trondheim (Norway); St. Olavs Hospital, Trondheim University Hospital, Trondheim (Norway)

    2017-07-15

    To evaluate the diagnostic relevance of T2-weighted (T2W) MRI-derived textural features relative to quantitative physiological parameters derived from diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) MRI in Gleason score (GS) 3+4 and 4+3 prostate cancers. 3T multiparametric-MRI was performed on 23 prostate cancer patients prior to prostatectomy. Textural features [angular second moment (ASM), contrast, correlation, entropy], apparent diffusion coefficient (ADC), and DCE pharmacokinetic parameters (K{sup trans} and V{sub e}) were calculated from index tumours delineated on the T2W, DW, and DCE images, respectively. The association between the textural features and prostatectomy GS and the MRI-derived parameters, and the utility of the parameters in differentiating between GS 3+4 and 4+3 prostate cancers were assessed statistically. ASM and entropy correlated significantly (p < 0.05) with both GS and median ADC. Contrast correlated moderately with median ADC. The textural features correlated insignificantly with K{sup trans} and V{sub e}. GS 4+3 cancers had significantly lower ASM and higher entropy than 3+4 cancers, but insignificant differences in median ADC, K{sup trans}, and V{sub e}. The combined texture-MRI parameters yielded higher classification accuracy (91%) than the individual parameter sets. T2W MRI-derived textural features could serve as potential diagnostic markers, sensitive to the pathological differences in prostate cancers. (orig.)

  5. Reduction of superoxide dismutase activity correlates with visualization of edema by T[sub 2]-weighted MR imaging in focal ischemic rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Imaizumi, Shigeki; Chang, LeeHong; Cohen, Yoram; Chan, P H; Weinstein, P R; James, T L [California Univ., San Francisco, CA (United States); Yoshimoto, Takashi

    1994-01-01

    This study investigated the correlation between in vivo serial T[sub 2]-weighted magnetic resonance (MR) imaging and changes in superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, and water, sodium ion (Na[sup +]), and potassium ion (K[sup +]) contents measured in vitro using rat brain following right middle cerebral artery occlusion in conjunction with bilateral common carotid artery (CCA) occlusion. One hour later the left CCA was released. Serial MR images showed edema developed from the outer cortex towards the center. The T[sub 2] signal intensity of the injured right cortex increased with time compared to that of the contralateral cortex. Increased Na[sup +] and water and decreased K[sup +] contents occurred in the injured cortex, indicating that serial T[sub 2]-weighted MR imaging reflects the changes in water content and Na[sup +] and K[sup +] concentrations determined by biochemical techniques. GSH-Px activity was little changed. Total SOD in the injured cortex decreased 1 hour after ischemia and remained low throughout the experiment. In contrast, SOD activity in the noninfarcted left cortex also decreased after 1 hour but returned to normal after 2 hours of ischemia. Our results suggest that oxygen free radicals are important in developing ischemic brain edema and cerebral infarction. (author).

  6. Assessment of Silent T1-weighted head imaging at 7 T

    Energy Technology Data Exchange (ETDEWEB)

    Costagli, Mauro; Tiberi, Gianluigi; Tosetti, Michela [Imago7 Foundation, Pisa (Italy); IRCCS Stella Maris, Laboratory of Medical Physics and Biotechnologies for Magnetic Resonance, Pisa (Italy); Symms, Mark R. [GE Applied Science Laboratory, Pisa (Italy); Angeli, Lorenzo [University of Pisa, Department of Translational Research and New Technologies in Medicine and Surgery, Pisa (Italy); Kelley, Douglas A.C. [GE Healthcare Technologies, San Francisco, CA (United States); Biagi, Laura [IRCCS Stella Maris, Laboratory of Medical Physics and Biotechnologies for Magnetic Resonance, Pisa (Italy); Farnetani, Andrea [University of Ferrara, Engineering Department, Ferrara (Italy); Materiacustica s.r.l., Ferrara (Italy); Rua, Catarina [University of Pisa, Department of Physics, Pisa (Italy); Donatelli, Graziella [Azienda Ospedaliero-Universitaria Pisana (AOUP), Neuroradiology Unit, Department of Diagnostic and Interventional Radiology, Pisa (Italy); Cosottini, Mirco [Imago7 Foundation, Pisa (Italy); University of Pisa, Department of Translational Research and New Technologies in Medicine and Surgery, Pisa (Italy)

    2016-06-15

    This study aimed to assess the performance of a ''Silent'' zero time of echo (ZTE) sequence for T1-weighted brain imaging using a 7 T MRI system. The Silent sequence was evaluated qualitatively by two neuroradiologists, as well as quantitatively in terms of tissue contrast, homogeneity, signal-to-noise ratio (SNR) and acoustic noise. It was compared to conventional T1-weighted imaging (FSPGR). Adequacy for automated segmentation was evaluated in comparison with FSPGR acquired at 7 T and 1.5 T. Specific absorption rate (SAR) was also measured. Tissue contrast and homogeneity in Silent were remarkable in deep brain structures and in the occipital and temporal lobes. Mean tissue contrast was significantly (p < 0.002) higher in Silent (0.25) than in FSPGR (0.11), which favoured automated tissue segmentation. On the other hand, Silent images had lower SNR with respect to conventional imaging: average SNR of FSPGR was 2.66 times that of Silent. Silent images were affected by artefacts related to projection reconstruction, which nevertheless did not compromise the depiction of brain tissues. Silent acquisition was 35 dB(A) quieter than FSPGR and less than 2.5 dB(A) louder than ambient noise. Six-minute average SAR was <2 W/kg. The ZTE Silent sequence provides high-contrast T1-weighted imaging with low acoustic noise at 7 T. (orig.)

  7. Cerebral signal intensity abnormalities on T2-weighted MR images in HIV patients with highly active antiretroviral therapy: relationship with clinical parameters and interval changes.

    Science.gov (United States)

    Hanning, Uta; Husstedt, Ingo W; Niederstadt, Thomas-Ulrich; Evers, Stefan; Heindel, Walter; Kloska, Stephan P

    2011-09-01

    The aim of this study was to assess the relationship between immune state and cerebral signal intensity abnormalities (SIAs) on T2-weighted magnetic resonance images in subjects with human immunodeficiency virus type 1 infection and highly active antiretroviral therapy. Thirty-two subjects underwent a total of 109 magnetic resonance studies. The presence of human immunodeficiency virus-associated neurocognitive disorder, categorized CD4(+) T lymphocyte count, and plasma viral load were assessed for relationship with the severity and interval change of SIAs for different anatomic locations of the brain. Subjects with multifocal patterns of SIAs had CD4(+) cell counts < 200 cells/μL in 66.0%, whereas subjects with diffuse patterns of SIAs had CD4(+) cell counts < 200 cells/μL in only 31.4% (P < .001). Subjects without SIAs in the basal ganglia had CD4(+) cell counts < 200 cells/μL in 37.0%, whereas subjects with minor and moderate SIAs in the basal ganglia had CD4(+) cell counts < 200 cells/μL in 78.3% and 80.0%, respectively (P < .005). The percentage of subjects with CD4(+) cell counts < 200 cells/μL was 85.7% when there were progressive periventricular SIA changes and 45.5% when periventricular SIA changes were stable in follow-up (P < .05). The presence and progression of cerebral SIAs on T2-weighted magnetic resonance images reflecting cerebral infection with human immunodeficiency virus are significantly related to impaired immune state as measured by CD4(+) cell count. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

  8. The hand: MR imaging with a 4.7-T magnet

    International Nuclear Information System (INIS)

    Wang, P.C.; Archer, A.; Rajan, S.; Carvlin, M.J.; Mun, S.K.; Nelson, M.C.

    1987-01-01

    MR images of normal and pathologic human hands were obtained using a 4.7-T magnet Varian system. Standard spin-echo techniques and inversion-recovery sequences were used to produce both T1- and T2-weighted images. The higher gradient (2 gauss/cm) of the 4.7-T system allows submillimeter resolution. A specially designed surface coil is used to improve the signal-to-noise ratio. The coil is elliptical and measures 3 inches by 4.5 inches. Axial, coronal, and sagittal images were obtained, revealing fine, detailed structures of the human hand. The joint capsule, ligaments and tendons, and vascular structures were clearly visible. The authors will show images of the normal anatomy of the hand, as well as pathologic lesions of inflammatory and crystalline arthropathy. Techniques and special problems of imaging the human hand with a 4.7-T system are discussed

  9. Subjective and objective image qualities: a comparison of sagittal T2 weighted spin-echo and turbo-spin-eco sequences in magnetic resonance imaging of the spine by use of a subjective ranking system

    Energy Technology Data Exchange (ETDEWEB)

    Goerres, G. [Institut fuer diagnostische Radiologie, Departement Radiologie, Universitaetskliniken, Kantonsspital Basel (Switzerland); Mader, I. [Radiologische Gemeinschaftspraxis Dres. Siems, Grossmann, Bayreuth (Germany); Proske, M. [Klinikum Rosenheim (Germany). Inst. fuer Diagnostische Radiologie

    1998-12-31

    We evaluated the subjective image impression of two different magnetic resonance (MR) sequences by using a subjective ranking system. This ranking system was based on 20 criteria describing several tissue characteristics such as the signal intensity of normal anatomical structures and the changes of signal intensities and shape of lesions as well as artefacts. MR of the vertebral spine was performed in 48 female and 52 male patients (mean age 44.8 years) referred consecutively for investigation of a back problem. Ninety-six pathologies were found in 82 patients. Sagittal and axial T1 weighted spin-echo before and after administration of Gadolinium (Gd-DOTA), and sagittal T2 weighted spin-echo (T2wSE) and Turbo-spin-echo (TSE) sequences were performed by means of surface coils. Using the subjective ranking system the sagittal T2wSE and sagittal TSE were compared. Both sequences were suitable for identification of normal anatomy and pathologic changes and there was no trend for increased detection of disease by one imaging sequence over the other. We found that sagittal TSE sequences can replace sagittal T2wSE sequences in spinal MR and that artefacts at the cervical and lumbar spine are less frequent using TSE, thus confirming previous studies. In this study, our ranking system reveiled, that there are differences between the subjective judgement of image qualities and objective measurement of SNR. However, this approach may not be helpful to compare two different MR sequences as it is limited to the anatomical area investigated and is time consuming. The subjective image impression, i.e. the quality of images, may not always be represented by physical parameters such as a signal-to-noise ratio (SNR), radiologists should try to define influences of image quality also by subjective parameters. (orig.)

  10. Electronic and magnetic properties of 1T-HfS{sub 2} by doping transition-metal atoms

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xu, E-mail: zhaoxu@htu.cn [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Wang, Tianxing; Wang, Guangtao [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Dai, Xianqi [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Department of Physics, Zhengzhou Normal University, Zhengzhou, Henan 450044 (China); Xia, Congxin [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Yang, Lin [School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007 (China)

    2016-10-15

    Highlights: • Pristine 1T-HfS{sub 2} is a semiconductor with indirect gaps of 1.250 eV • Magnetism can be observed for V, Cr, Mn, Fe, Co, and Cu doping. • Strong p–d hybridization was found between TM 3d orbitals and S 3p orbitals. • V-doped 1T-HfS{sub 2} is ideal for spin injection. - Abstract: We explored the electronic and magnetic properties of 1T-HfS{sub 2} doped by transition metal (TM) atom using the first-principles calculation. We doped the transition metal atoms from the IIIB to VIB groups in nonmagnetic 1T-HfS{sub 2}. Numerical results show that the pristine 1T-HfS{sub 2} is a semiconductor with indirect gaps of 1.250 eV. Magnetism can be observed for V, Cr, Mn, Fe, Co, and Cu doping. The polarized charges mainly arise from the localized 3d electrons of the TM atom. The strong p–d hybridization was found between the 3d orbitals of TM and 3p orbitals of S. The substituted 1T-HfS{sub 2} can be a metal, semiconductor or half-metal. Analysis of the band structure and magnetic properties indicates that TM-doped HfS{sub 2} (TM = V, Fe, Cu) are promising systems to explore two-dimensional diluted magnetic semiconductors. The formation energy calculations also indicate that it is energetically favorable and relatively easier to incorporate transition metal atom into the HfS{sub 2} under S-rich experimental conditions. In contrast, V-doped HfS{sub 2} has relatively wide half-metallic gap and low formation energy. So V-doped 1T-HfS{sub 2} is ideal for spin injection, which is important for application in semiconductor spintronics.

  11. Heavily T2-weighted MR myelography vs CT myelography in spontaneous intracranial hypotension.

    Science.gov (United States)

    Wang, Y-F; Lirng, J-F; Fuh, J-L; Hseu, S-S; Wang, S-J

    2009-12-01

    To assess the diagnostic accuracy of heavily T2-weighted magnetic resonance myelography (MRM) in patients with spontaneous intracranial hypotension (SIH). Patients with SIH were recruited prospectively, and first underwent MRM and then computed tomographic myelography (CTM). The results of MRM were validated with the gold standard, CTM, focusing on 1) CSF leaks along the nerve roots, 2) epidural CSF collections, and 3) high-cervical (C1-3) retrospinal CSF collections. Comparisons of these 3 findings between the 2 studies were made by kappa statistics and agreement rates. Targeted epidural blood patches (EBPs) were placed at the levels of CSF leaks if supportive treatment failed. Nineteen patients (6 men and 13 women, mean age 37.9 +/- 8.6 years) with SIH completed the study. MRM did not differ from CTM in the detection rates of CSF leaks along the nerve roots (84% vs 74%, p = 0.23), high-cervical retrospinal CSF collections (32% vs 16%, p = 0.13), and epidural CSF collections (89% vs 79%, p = 0.20). MRM demonstrated more spinal levels of CSF leaks (2.2 +/- 1.7 vs 1.5 +/- 1.5, p = 0.011) and epidural collections (12.2 +/- 5.9 vs 7.1 +/- 5.8, p localizing CSF leaks for patients with spontaneous intracranial hypotension. This noninvasive technique may be an alternative to computed tomographic myelography before targeted epidural blood patches.

  12. T2 black lesions on routine knee MRI: differential considerations

    International Nuclear Information System (INIS)

    Wadhwa, Vibhor; Cho, Gina; Moore, Daniel; Pezeshk, Parham; Coyner, Katherine; Chhabra, Avneesh

    2016-01-01

    The majority of abnormal findings or lesions on T2-weighted fast spin-echo (FSE) magnetic resonance imaging (MRI) are hyperintense due to increased perfusion or fluid content, such as infections, tumours or synovitis. Hypointense lesions on T2-weighted images (both fat-suppressed and non-fat-suppressed) are less common and can sometimes be overlooked. Such lesions have limited differential diagnostic possibilities, and include vacuum phenomenon, loose body, tenosynovial giant cell tumour, rheumatoid arthritis, haemochromatosis, gout, amyloid, chondrocalcinosis, hydroxyapetite deposition disease, lipoma arborescens, arthrofibrosis and iatrogenic lesions. These lesions often show characteristic appearances and predilections in the knee. In this article, the authors describe the MRI features of hypointense T2 lesions on routine knee MRI and outline a systematic diagnostic approach towards their evaluation. (orig.)

  13. Evaluation of the liver in normal subjects and cases of hepatic diseases by ultra-low field (0.02 T) magnetic resonance imaging

    International Nuclear Information System (INIS)

    Iwasaki, Yoshie

    1988-01-01

    A total of 123 cases (45 controls, 14 liver cirrhoses, 6 fatty livers, 22 cavernous hemangiomas, 14 hepatomas, 9 metastases, 10 cysts, and 3 hemorrhagic cysts) were studied by ultra-low field magnetic resonance imaging. On T1-weighted images, the means of the intesity ratio in controls were 0.703±0.074 (liver to spleen), 0.658±0.073 (liver to kidney) and 0.932±0.058 (spleen to kidney). On T2-weighted images, the means of the intensity ratios in controls were 0.449±0.083 (liver to spleen), 0.363±0.069 (liver to kidney) and 0.822±0.115 (spleen to kidney). In liver cirrhosis, on T2-weighted images, the intensity ratio of liver to kidney and spleen to kidney. In liver cirrhosis were significantly higher than those in controls. In fatty liver, the intensity ratio of liver to spleen on T1-weighted image, and those of liver to spleen and liver to kidney on T2-weighted image were higher than those in controls. On T2-weighted images, the intensity ratio of tumor to liver in hepatic cavernous hemangioma were significantly higher than those in hepatocellular carcinoma and metastatic liver tumor. Ultra-low field magnetic resonance imaging with the intensity ratio of tumor to liver was valuable in distinguishing between hepatic cavernous hemangioma and hepatic malignancies and it was also possible to distinguish hemorrhagic liver cyst from non-hemorrhagic liver cyst. (author)

  14. Evaluation of sclerosis in Modic changes of the spine using susceptibility-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Böker, Sarah M., E-mail: Sarah-maria.boeker@charite.de [Department of Radiology, Charité, Charitéplatz 1, 10117 Berlin (Germany); Bender, Yvonne Y., E-mail: Yi-na.bender@charite.de [Department of Radiology, Charité, Charitéplatz 1, 10117 Berlin (Germany); Adams, Lisa C., E-mail: Lisa.adams@charite.de [Department of Radiology, Charité, Charitéplatz 1, 10117 Berlin (Germany); Fallenberg, Eva M., E-mail: Eva.fallenberg@charite.de [Department of Radiology, Charité, Augustenburger Platz 1, 13353 Berlin (Germany); Wagner, Moritz, E-mail: Moritz.wagner@charite.de [Department of Radiology, Charité, Charitéplatz 1, 10117 Berlin (Germany); Hamm, Bernd, E-mail: Bernd.hamm@charite.de [Department of Radiology, Charité, Charitéplatz 1, 10117 Berlin (Germany); Makowski, Marcus R., E-mail: Marcus.makowski@charite.de [Department of Radiology, Charité, Charitéplatz 1, 10117 Berlin (Germany)

    2017-03-15

    Highlights: • SWMR allows a reliable detection of sclerosis in Modic changes. • SWI has a better accuracy for detection of sclerosis in Modic changes than T1/T2w MR. • By applying SWMR the use of additional CT/radiography can be minimized. - Abstract: Purpose: To evaluate the diagnostic performance of susceptibility-weighted magnetic resonance imaging (SWMR) for the differentiation of sclerotic and non-sclerotic Modic changes (MC) of the spine compared to computed tomography (CT) and radiographs. Materials and methods: The Institutional Ethics-Review-Board approved this prospective study in advance. Written consent was obtained from all subjects. SWMR and standard T1/T2 MR of the cervical (n = 21) and/or lumbar spine (n = 34) were performed in 54 patients. 21 patients served as control. 18 patients were evaluated with CT; in all other patients radiographs were available. 67 Modic changes were identified on T1/T2 MR. On SWMR changes were classified as sclerotic and non-sclerotic based on signal intensity measurements. The sensitivity and specificity of SWMR and T1/T2 MR for differentiating between sclerotic and non-sclerotic Modic changes were determined with CT and radiographs as reference standard. Results: On SWMR, signal measurements between sclerotic and non-sclerotic Modic changes differed significantly (p < 0.01). On T1- and T2-weighted MR no significant difference (p > 0.05) was measured. On SWMR, a reliable differentiation between sclerotic and non-sclerotic Modic changes could be achieved, with a sensitivity of 100% and specificity of 95%. In contrast, the combination of T1-/T2-weighted MR yielded a significantly lower sensitivity to detect sclerosis (20%). Conclusion: SWMR allows a reliable detection of sclerosis in Modic changes with a higher accuracy compared to standard spine MR sequences, using radiographs and CT as reference standard.

  15. Primary biliary cirrhosis: Evaluation with T2-weighted MR imaging and MR cholangiopancreatography

    Energy Technology Data Exchange (ETDEWEB)

    Haliloglu, Nuray [Ankara University, Faculty of Medicine, Department of Radiology, Ibni Sina Hospital, 06100 Ankara (Turkey)], E-mail: nurayunsal2@hotmail.com; Erden, Ayse; Erden, Ilhan [Ankara University, Faculty of Medicine, Department of Radiology, Ibni Sina Hospital, 06100 Ankara (Turkey)

    2009-03-15

    Purpose: The aim of this retrospective study is to evaluate the role of T2-weighted MR imaging (MRI) and MR cholangiopancreatography (MRCP) findings in the diagnosis of primary biliary cirrhosis (PBC). Materials and methods: The following T2-weighted MRI and MRCP findings: segmental hepatic atrophy/hypertrophy, irregular liver surface, parenchymal lace-like fibrosis, rounded low signal intensity lesions centering portal vein branches (periportal halo sign), periportal hyperintensity (cuffing), splenomegaly, ascites, lymphadenopathy, venous collaterals, and the configuration of intrahepatic biliary ducts were reviewed for their diagnostic significance by two observers in 13 female patients (mean age: 49 years) with PBC. Discordant readings of the observers were resolved at consensus. Results: When parenchymal lace-like fibrosis and periportal halo sign were seen together the sensitivity of T2-weighted MR images was 69%. In six cases periportal hyperintensity (cuffing) and periportal halo sign were seen together. Segmental hypertrophy was present in nine patients and hepatic surface irregularity due to regenerative nodules were present in 10 patients. Lymphadenopathy was seen in 10, splenomegaly was seen in 5, collateral vascular structures were seen in 2 and minimal perihepatic free fluid was seen in 2 patients. MRCP images revealed various mild irregularity in the intrahepatic bile ducts in 8 patients and focal narrowing at the common bile duct level in 1 patient. Conclusion: MRI and MRCP may support the clinical and laboratory findings of PBC even in the early stages of the disease. MRI can also be a choice of method for the recommended prolonged follow up.

  16. Primary biliary cirrhosis: Evaluation with T2-weighted MR imaging and MR cholangiopancreatography

    International Nuclear Information System (INIS)

    Haliloglu, Nuray; Erden, Ayse; Erden, Ilhan

    2009-01-01

    Purpose: The aim of this retrospective study is to evaluate the role of T2-weighted MR imaging (MRI) and MR cholangiopancreatography (MRCP) findings in the diagnosis of primary biliary cirrhosis (PBC). Materials and methods: The following T2-weighted MRI and MRCP findings: segmental hepatic atrophy/hypertrophy, irregular liver surface, parenchymal lace-like fibrosis, rounded low signal intensity lesions centering portal vein branches (periportal halo sign), periportal hyperintensity (cuffing), splenomegaly, ascites, lymphadenopathy, venous collaterals, and the configuration of intrahepatic biliary ducts were reviewed for their diagnostic significance by two observers in 13 female patients (mean age: 49 years) with PBC. Discordant readings of the observers were resolved at consensus. Results: When parenchymal lace-like fibrosis and periportal halo sign were seen together the sensitivity of T2-weighted MR images was 69%. In six cases periportal hyperintensity (cuffing) and periportal halo sign were seen together. Segmental hypertrophy was present in nine patients and hepatic surface irregularity due to regenerative nodules were present in 10 patients. Lymphadenopathy was seen in 10, splenomegaly was seen in 5, collateral vascular structures were seen in 2 and minimal perihepatic free fluid was seen in 2 patients. MRCP images revealed various mild irregularity in the intrahepatic bile ducts in 8 patients and focal narrowing at the common bile duct level in 1 patient. Conclusion: MRI and MRCP may support the clinical and laboratory findings of PBC even in the early stages of the disease. MRI can also be a choice of method for the recommended prolonged follow up.

  17. White Matter Hyperintensities on T2-Weighted MRI Images among DNA-Verified Older Familial Hypercholesterolemia Patients

    Energy Technology Data Exchange (ETDEWEB)

    Hyttinen, L. (Dept. of Internal Medicine, North Karelia Central Hospital, Joensuu (Finland)); Autti, T.; Soljanlahti, S. (Medical Imaging Center, Helsinki Univ. Central Hospital, Helsinki (Finland)); Rauma, S. (Dept. of Radiology, North Karelia Central Hospital, Joensuu (Finland)); Vuorio, A.F. (Dept. of Medicine, Univ. of Helsinki, Helsinki (Finland)); Strandberg, T.E. (Dept. of Health Sciences/Geriatrics, Univ. of Oulu, Oulu (Finland))

    2009-04-15

    Background: Familial hypercholesterolemia (FH) is a genetic disorder, causing an increased risk of coronary heart disease (CHD) if untreated. Silent brain infarctions and white matter hyperintensities (WMHIs) observed on T2-weighted magnetic resonance images (MRI) are associated with increased risk for stroke and myocardial infarction. Age is a strong predictor of WMHIs. Purpose: To use MRI to assess the presence of clinically silent brain lesions in older FH patients, and to compare the occurrence and size of these lesions in older FH patients with middle-aged FH patients and healthy controls. Material and Methods: A total of 43 older (age = 65 years) FH patients with the same FH North Karelia mutation, living in Finland, were identified. In this comprehensive cohort, 1.5T brain MRI was available for 33 individuals (age 65-84 years, M/F 9/24, mean duration of statin treatment 15.3 years). This group was divided into two age categories: 65-74 years (FHe1 group, n=23) and 75-84 years (FHe2 group, n=10). Infarcts, including lacunas, and WMHIs on T2-weighted images were recorded. Data from brain MRI were compared to those of a group of middle-aged FH patients with CHD (n=19, age 48-64 years) and with middle-aged healthy controls (n=29, age 49-63 years). Results: Only two (6%) of the older FH patients had clinically silent brain infarcts detected by MRI. The amount of large WMHIs (>5 mm in diameter) was similar in the FHe1 group compared with the groups of middle-aged FH patients and healthy controls, even though the FHe1 group was 13 years older. The total amount of WMHIs and the amount of large WMHIs were greatest in the FHe2 group. Conclusion: FH patients aged 65 to 74 years receiving long-term statin treatment (15 years) did not have more WMHIs on brain MRI compared to middle-aged FH patients and healthy controls.

  18. White Matter Hyperintensities on T2-Weighted MRI Images among DNA-Verified Older Familial Hypercholesterolemia Patients

    International Nuclear Information System (INIS)

    Hyttinen, L.; Autti, T.; Soljanlahti, S.; Rauma, S.; Vuorio, A.F.; Strandberg, T.E.

    2009-01-01

    Background: Familial hypercholesterolemia (FH) is a genetic disorder, causing an increased risk of coronary heart disease (CHD) if untreated. Silent brain infarctions and white matter hyperintensities (WMHIs) observed on T2-weighted magnetic resonance images (MRI) are associated with increased risk for stroke and myocardial infarction. Age is a strong predictor of WMHIs. Purpose: To use MRI to assess the presence of clinically silent brain lesions in older FH patients, and to compare the occurrence and size of these lesions in older FH patients with middle-aged FH patients and healthy controls. Material and Methods: A total of 43 older (age = 65 years) FH patients with the same FH North Karelia mutation, living in Finland, were identified. In this comprehensive cohort, 1.5T brain MRI was available for 33 individuals (age 65-84 years, M/F 9/24, mean duration of statin treatment 15.3 years). This group was divided into two age categories: 65-74 years (FHe1 group, n=23) and 75-84 years (FHe2 group, n=10). Infarcts, including lacunas, and WMHIs on T2-weighted images were recorded. Data from brain MRI were compared to those of a group of middle-aged FH patients with CHD (n=19, age 48-64 years) and with middle-aged healthy controls (n=29, age 49-63 years). Results: Only two (6%) of the older FH patients had clinically silent brain infarcts detected by MRI. The amount of large WMHIs (>5 mm in diameter) was similar in the FHe1 group compared with the groups of middle-aged FH patients and healthy controls, even though the FHe1 group was 13 years older. The total amount of WMHIs and the amount of large WMHIs were greatest in the FHe2 group. Conclusion: FH patients aged 65 to 74 years receiving long-term statin treatment (15 years) did not have more WMHIs on brain MRI compared to middle-aged FH patients and healthy controls

  19. Differentiating laryngeal carcinomas from precursor lesions by diffusion-weighted magnetic resonance imaging at 3.0 T: a preliminary study.

    Directory of Open Access Journals (Sweden)

    De-Sheng Shang

    Full Text Available BACKGROUND: Diffusion-weighted magnetic resonance imaging (DWI has been introduced in head and neck cancers. Due to limitations in the performance of laryngeal DWI, including the complex anatomical structure of the larynx leading to susceptibility effects, the value of DWI in differentiating benign from malignant laryngeal lesions has largely been ignored. We assessed whether a threshold for the apparent diffusion coefficient (ADC was useful in differentiating preoperative laryngeal carcinomas from precursor lesions by turbo spin-echo (TSE DWI and 3.0-T magnetic resonance. METHODS: We evaluated DWI and the ADC value in 33 pathologically proven laryngeal carcinomas and 17 precancerous lesions. RESULTS: The sensitivity, specificity, and accuracy were 81.8%, 64.7%, 76.0% by laryngostroboscopy, respectively. The sensitivity, specificity, and accuracy of conventional magnetic resonance imaging were 90.9%, 76.5%, 86.0%, respectively. Qualitative DWI analysis produced sensitivity, specificity, and accuracy values of 100.0, 88.2, and 96.0%, respectively. The ADC values were lower for patients with laryngeal carcinoma (mean 1.195±0.32×10(-3 mm(2/s versus those with laryngeal precancerous lesions (mean 1.780±0.32×10(-3 mm(2/s; P<0.001. ROC analysis showed that the area under the curve was 0.956 and the optimum threshold for the ADC was 1.455×10(-3 mm(2/s, resulting in a sensitivity of 94.1%, a specificity of 90.9%, and an accuracy of 92.9%. CONCLUSIONS: Despite some limitations, including the small number of laryngeal carcinomas included, DWI may detect changes in tumor size and shape before they are visible by laryngostroboscopy. The ADC values were lower for patients with laryngeal carcinoma than for those with laryngeal precancerous lesions. The proposed cutoff for the ADC may help distinguish laryngeal carcinomas from laryngeal precancerous lesions.

  20. Bone marrow response in treated patients with Gaucher disease: evaluation by T1-weighted magnetic resonance images and correlation with reduction in liver and spleen volume

    International Nuclear Information System (INIS)

    Terk, M.R.; Dardashti, S.; Liebman, H.A.

    2000-01-01

    Purpose. To determine whether T1-weighted magnetic resonance (MR) images can demonstrate response in the marrow of patients with type 1 Gaucher disease treated with enzyme replacement therapy (ERT) and to determine whether a relationship exists between liver and spleen volume reductions and visible marrow changes.Patients. Forty-two patients with type 1 Gaucher disease were evaluated on at least two occasions. Thirty-two patients received ERT. Of these patients, 15 had a baseline examination prior to the initiation of ERT. The remaining 10 patients did not receive ERT.Design. T1-weighted and gradient recalled echo (GRE) coronal images of the femurs and hips were obtained. Concurrently, liver and spleen volumes were determined using contiguous breath-hold axial gradient-echo images. T1-weighted images of the hips and femurs were evaluated to determine change or lack of change in the yellow marrow.Results. Of the 32 patients receiving ERT, 14 (44%) demonstrated increased signal on T1-weighted images suggesting an increase in the amount of yellow marrow. If only the 15 patients with a baseline examination were considered, the response rate to ERT was 67%. Using Student's t-test a highly significant correlation (P<0.005) was found between marrow response and reduction in liver and spleen volume.Conclusions. Marrow changes in patients receiving ERT can be detected by T1-weighted images. This response correlated with reductions in visceral volumes (P<0.0005). (orig.)

  1. Characteristic signal changes in the pontine base on T2- and multishot diffusion-weighted images in spinocerebellar ataxia type 1

    International Nuclear Information System (INIS)

    Adachi, M.; Kawanami, T.; Ohshima, H.; Hosoya, T.

    2006-01-01

    The aim of the present study was to demonstrate characteristic signal changes of the pontine base on T2-weighted images of patients with SCA 1, and to elucidate the relationship between abnormal high-intensities of the pontine base on T2-weighted images and the findings on multishot diffusion-weighted images. We assessed abnormal signals of the pontine base on T2-weighted images from 50 controls and six patients with SCA 1 diagnosed by genetic analysis. At the same time, we evaluated the degeneration of the transverse pontine fibers in the pontine base by multishot diffusion-weighted imaging. A midline high-intensity was seen in the pontine base on T2-weighted images in two of the 50 controls and five of the six patients with SCA 1. The midline high-intensity had a sensitivity of 83.3% for patients and a specificity of 96.0% for controls. Multishot diffusion-weighted imaging demonstrated the degeneration - the amorphous-pattern signal - of the transverse pontine fibers in four (66.7%) of the six patients. In the other two patients, the zebra-pattern signal was seen in the pontine base. The midline high-intensity on T2-weighted images appears to be one of characteristic MRI findings of SCA 1. Multishot diffusion-weighted imaging suggested that the midline high-intensity should reflect the degeneration of the transverse pontine fibers. (orig.)

  2. Simultaneous Measurement of T2 and Apparent Diffusion Coefficient (T2+ADC) in the Heart With Motion-Compensated Spin Echo Diffusion-Weighted Imaging

    Science.gov (United States)

    Aliotta, Eric; Moulin, Kévin; Zhang, Zhaohuan; Ennis, Daniel B.

    2018-01-01

    Purpose To evaluate a technique for simultaneous quantitative T2 and apparent diffusion coefficient (ADC) mapping in the heart (T2+ADC) using spin echo (SE) diffusion-weighted imaging (DWI). Theory and Methods T2 maps from T2+ADC were compared with single-echo SE in phantoms and with T2-prepared (T2-prep) balanced steady-state free precession (bSSFP) in healthy volunteers. ADC maps from T2+ADC were compared with conventional DWI in phantoms and in vivo. T2+ADC was also demonstrated in a patient with acute myocardial infarction (MI). Results Phantom T2 values from T2+ADC were closer to a single-echo SE reference than T2-prep bSSFP (−2.3 ± 6.0% vs 22.2 ± 16.3%; P T2 values from T2+ADC were significantly shorter than T2-prep bSSFP (35.8 ± 3.1 vs 46.8 ± 3.8 ms; P T2+ADC and conventional motion-compensated DWI (1.39 ± 0.18 vs 1.38 ± 0.18 mm2/ms; P = N.S.). In the patient, T2 and ADC were both significantly elevated in the infarct compared with remote myocardium (T2: 40.4 ± 7.6 vs 56.8 ± 22.0; P T2+ADC generated coregistered, free-breathing T2 and ADC maps in healthy volunteers and a patient with acute MI with no cost in accuracy, precision, or scan time compared with DWI. PMID:28516485

  3. Comparison of two-dimensional fast spin echo T2 weighted sequences and three-dimensional volume isotropic T2 weighted fast spin echo (VISTA) MRI in the evaluation of triangular fibrocartilage of the wrist.

    Science.gov (United States)

    Park, Hee Jin; Lee, So Yeon; Kang, Kyung A; Kim, Eun Young; Shin, Hun Kyu; Park, Se Jin; Park, Jai Hyung; Kim, Eugene

    2018-04-01

    To compare image quality of three-dimensional volume isotropic T 2 weighted fast spin echo (3D VISTA) and two-dimensional (2D) T 2 weighted images (T2WI) for evaluation of triangular fibrocartilage (TFC) and to investigate whether 3D VISTA can replace 2D T 2 WI in evaluating TFC injury. This retrospective study included 69 patients who received wrist MRIs using both 2D T 2 WI and 3D VISTA techniques for assessment of wrist pathology, including TFC injury. Two radiologists measured the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) of the two sequences. The anatomical identification score and diagnostic performance were independently assessed by two interpreters. The diagnostic abilities of 3D VISTA and 2D T 2 WI were analysed by sensitivity, specificity and accuracy for diagnosing TFC injury using surgically or clinically confirmed diagnostic reference standards. 17 cases (25%) were classified as having TFC injury. 2 cases (12%) were diagnosed surgically, and 15 cases (88%) were diagnosed by physical examination. 52 cases (75%) were diagnosed as having intact TFC. 8 of these cases (15%) were surgically confirmed, while the others were diagnosed by physical examination and clinical findings. The 3D VISTA images had significantly higher SNR and CNR values for the TFC than 2D T 2 WI images. The scores of 3D VISTA's total length, full width and sharpness were similar to those of 2D T 2 WI. We were unable to find a significant difference between 3D VISTA and 2D T 2 WI in the ability to diagnose TFC injury. 3D VISTA image quality is similar to that of 2D T 2 WI for TFC evaluation and is also excellent for tissue contrast. 3D VISTA can replace 2D images in TFC injury assessment. Advances in knowledge: 3D VISTA image quality is similar to that of 2D T 2 WI for TFC evaluation and is also excellent for tissue contrast. 3D VISTA can replace 2D images in TFC injury assessment.

  4. Utility of echo-planar gradient-echo T2*-weighted MR images in patients with primary intracerebral hemorrhage

    International Nuclear Information System (INIS)

    Yokoe, Toshio; Yoshida, Tazuka; Kobayashi, Nozomu; Nakamura, Yukihiro; Kubota, Kazuyuki

    2005-01-01

    Magnetic resonance imaging (MRI) has the potential to reveal residues of intracerabral hemorrhage (ICH) throughout life because of the high sensitivity for iron-containing compounds. Gradient-echo T2 * -weighted MR imaging (T2 * MRI) requiring short times for complete acquisition is known to detect small areas of signal loss without surrounding edema representing microbleeds (MBs). MBs in the basal ganglia including the thalami are suggested to be closely related to intracerebral atherosclerotic microangiopathy. We looked for more than 3 MBs in basal ganglia or thalamus of patients with and without episodes of previous ICH. Twelve patients with previous hemorrhagic stroke and 82 without were studied. Multiple MBs in those regions were significantly more frequent in patients with recurrent ICH. In addition, a 76-year-old woman with a history of hypertension was transferred to our hospital for treatment of head injury. She had multiple incidental old basal ganglionic and thalamic MBs. The patient had an asymptomatic primary ICH on computed tomography (CT) 3 months later. In conclusion, MR evidence of multiple MBs in the basal ganglia and thalamus might identify patients at a risk for new and recurrent ICH. Therefore, patients with multiple MBs in those regions should be treated for cerebrovascular risk factors, especially hypertension. Our results appear to confirm the utility of T2 * MRI in hemorrhagic stroke. (author)

  5. Nuclear magnetic resonance metabonomic profiling using tO2PLS

    Energy Technology Data Exchange (ETDEWEB)

    Kirwan, Gemma M., E-mail: gemma.kirwan@gmail.com [Department of Chemistry, School of Applied Sciences, RMIT University, City Campus, Vic 3001 (Australia); Bioinformatics Center, Institute for Chemical Research, Kyoto University, Gokasho Uji, Kyoto (Japan); Hancock, Timothy [Bioinformatics Center, Institute for Chemical Research, Kyoto University, Gokasho Uji, Kyoto (Japan); Hassell, Kathryn [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Vic 3083 (Australia); Niere, Julie O. [Department of Chemistry, School of Applied Sciences, RMIT University, City Campus, Vic 3001 (Australia); Nugegoda, Dayanthi [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Vic 3083 (Australia); Goto, Susumu [Bioinformatics Center, Institute for Chemical Research, Kyoto University, Gokasho Uji, Kyoto (Japan); Adams, Michael J. [Department of Chemistry, School of Applied Sciences, RMIT University, City Campus, Vic 3001 (Australia)

    2013-06-05

    Graphical abstract: -- Highlights: •Transposition of O2PLS input matrix (tO2PLS) to analyze metabonomics data. •tO2PLS specific components describe features that separate and define sample groups. •Application of tO2PLS to a {sup 1}H NMR metabonomics study of black bream fish. -- Abstract: Blood plasma collected from adult fish (black bream, Sparidae) exposed to a dose of 5 mg kg{sup −1} 17β-estradiol underwent metabonomic profiling using nuclear magnetic resonance (NMR). An extension of the orthogonal 2 projection to latent structure (O2PLS) analysis, tO2PLS, was proposed and utilized to classify changes between the control and experimental metabolic profiles. As a bidirectional modeling tool, O2PLS examines the (variable) commonality between two different data blocks, and extracts the joint correlations as well as the unique variations present within each data block. tO2PLS is a proposed matrix transposition of O2PLS to allow for commonality between experiments (spectral profiles) to be observed, rather than between sample variables. tO2PLS analysis highlighted two potential biomarkers, trimethylamine-N-oxide (TMAO) and choline, that distinguish between control and 17β-estradiol exposed fish. This study presents an alternative way of examining spectroscopic (metabolite) data, providing a method for the visual assessment of similarities and differences between control and experimental spectral features in large data sets.

  6. Nuclear magnetic resonance metabonomic profiling using tO2PLS

    International Nuclear Information System (INIS)

    Kirwan, Gemma M.; Hancock, Timothy; Hassell, Kathryn; Niere, Julie O.; Nugegoda, Dayanthi; Goto, Susumu; Adams, Michael J.

    2013-01-01

    Graphical abstract: -- Highlights: •Transposition of O2PLS input matrix (tO2PLS) to analyze metabonomics data. •tO2PLS specific components describe features that separate and define sample groups. •Application of tO2PLS to a 1 H NMR metabonomics study of black bream fish. -- Abstract: Blood plasma collected from adult fish (black bream, Sparidae) exposed to a dose of 5 mg kg −1 17β-estradiol underwent metabonomic profiling using nuclear magnetic resonance (NMR). An extension of the orthogonal 2 projection to latent structure (O2PLS) analysis, tO2PLS, was proposed and utilized to classify changes between the control and experimental metabolic profiles. As a bidirectional modeling tool, O2PLS examines the (variable) commonality between two different data blocks, and extracts the joint correlations as well as the unique variations present within each data block. tO2PLS is a proposed matrix transposition of O2PLS to allow for commonality between experiments (spectral profiles) to be observed, rather than between sample variables. tO2PLS analysis highlighted two potential biomarkers, trimethylamine-N-oxide (TMAO) and choline, that distinguish between control and 17β-estradiol exposed fish. This study presents an alternative way of examining spectroscopic (metabolite) data, providing a method for the visual assessment of similarities and differences between control and experimental spectral features in large data sets

  7. Scaled signal intensity of uterine fibroids based on T2-weighted MR images: a potential objective method to determine the suitability for magnetic resonance-guided focused ultrasound surgery of uterine fibroids.

    Science.gov (United States)

    Park, Hyun; Yoon, Sang-Wook; Sokolov, Amit

    2015-12-01

    Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS) is a non-invasive method to treat uterine fibroids. To help determine the patient suitability for MRgFUS, we propose a new objective measure: the scaled signal intensity (SSI) of uterine fibroids in T2 weighted MR images (T2WI). Forty three uterine fibroids in 40 premenopausal women were included in this retrospective study. SSI of each fibroid was measured from the screening T2WI by standardizing its mean signal intensity to a 0-100 scale, using reference intensities of rectus abdominis muscle (0) and subcutaneous fat (100). Correlation between the SSI and the non-perfused volume (NPV) ratio (a measure for treatment success) was calculated. Pre-treatment SSI showed a significant inverse-correlation with post treatment NPV ratio (p < 0.05). When dichotomizing NPV ratio at 45 %, the optimal cut off value of the SSI was found to be 16.0. A fibroid with SSI value 16.0 or less can be expected to have optimal responses. The SSI of uterine fibroids in T2WI can be suggested as an objective parameter to help in patient selection for MRgFUS. • Signal intensity of fibroid in MR images predicts treatment response to MRgFUS. • Signal intensity is standardized into scaled form using adjacent tissues as references. • Fibroids with SSI less than 16.0 are expected to have optimal responses.

  8. Diffusion-weighted magnetic resonance imaging in monitoring rectal cancer response to neoadjuvant chemoradiotherapy.

    Science.gov (United States)

    Barbaro, Brunella; Vitale, Renata; Valentini, Vincenzo; Illuminati, Sonia; Vecchio, Fabio M; Rizzo, Gianluca; Gambacorta, Maria Antonietta; Coco, Claudio; Crucitti, Antonio; Persiani, Roberto; Sofo, Luigi; Bonomo, Lorenzo

    2012-06-01

    To prospectively monitor the response in patients with locally advanced nonmucinous rectal cancer after chemoradiotherapy (CRT) using diffusion-weighted magnetic resonance imaging. The histopathologic finding was the reference standard. The institutional review board approved the present study. A total of 62 patients (43 men and 19 women; mean age, 64 years; range, 28-83) provided informed consent. T(2)- and diffusion-weighted magnetic resonance imaging scans (b value, 0 and 1,000 mm(2)/s) were acquired before, during (mean 12 days), and 6-8 weeks after CRT. We compared the median apparent diffusion coefficients (ADCs) between responders and nonresponders and examined the associations with the Mandard tumor regression grade (TRG). The postoperative nodal status (ypN) was evaluated. The Mann-Whitney/Wilcoxon two-sample test was used to evaluate the relationships among the pretherapy ADCs, extramural vascular invasion, early percentage of increases in ADCs, and preoperative ADCs. Low pretreatment ADCs (23% ADC increase had a 96.3% negative predictive value for TRG 4. In 9 of 16 complete responders, CRT-related tumor downsizing prevented ADC evaluations. The preoperative ADCs were significantly different (p = .0012) between the patients with and without downstaging (preoperative ADC ≥1.4 × 10(-3)mm(2)/s showed a positive and negative predictive value of 78.9% and 61.8%, respectively, for response assessment). The TRG 1 and TRG 2-4 groups were not significantly different. Diffusion-weighted magnetic resonance imaging seems to be a promising tool for monitoring the response to CRT. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Confirmation of T1-Bright Vein of Galen Aneurysm Spontaneous Thrombosis by Subtraction Magnetic Resonance Venography: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Irfan, M.; Lohman, B.; McKinney, A.M. (Dept. of Radiology/Neuroradiology, Univ. of Minnesota, Minneapolis, Minnesota (United States))

    2009-08-15

    Spontaneous thrombosis of a vein of Galen aneurysmal malformation (VOGM) is rare. We describe a 2-month-old patient with a patent VOGM and hydrocephalus, also confirmed patent at 6 months, but with subsequent lack of filling on pre-embolization catheter digital subtraction angiography (DSA) at 9 months' age. Due to the presence of T1- and T2-bright signal, noncontrast T1-weighted images (T1WI), T2-weighted images (T2WI), two-dimensional (2D) time-of-flight (TOF) magnetic resonance venography (MRV), and postcontrast T1WI were ambiguous for patency. However, subtracting the pre- from the postcontrast MRV images confirmed closure compared to subtracted images at 6 months' age. The factors contributing to thrombosis were likely a combination of a disproportionately small straight sinus, ventriculostomy, and contrast medium from DSA.

  10. Transient Splenial Lesion of Corpus Callosum Associated with Antiepileptic Drug: Conventional and Diffusion-weighted Magnetic Resonance Images

    Energy Technology Data Exchange (ETDEWEB)

    Hakyemez, B.; Erdogan, C.; Yildirim, N.; Gokalp, G.; Parlak, M. [Uludag Univ. Medical School, Bursa (Turkey). Dept. of Radiology

    2005-11-01

    Transient focal lesions of splenium of corpus callosum can be seen as a component of many central nervous system diseases, including antiepileptic drug toxicity. The conventional magnetic resonance (MR) findings of the disease are characteristic and include ovoid lesions with high signal intensity at T2-weighted MRI. Limited information exists about the diffusion-weighted MRI characteristics of these lesions vanishing completely after a period of time. We examined the conventional, FLAIR, and diffusion-weighted MR images of a patient complaining of depressive mood and anxiety disorder after 1 year receiving antiepileptic medication.

  11. Cholangiopancreatography for magnetic resonance (CPRM), using T2 - TSE technique and reconstructions 3D - Experience with 38 patients

    International Nuclear Information System (INIS)

    Esguerra Espinosa, Monica

    1997-01-01

    Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive diagnostic method for the study of the biliary system that does not require contrast media or exposure to ionising radiation. Thirty-eight patients were studied; five apparently healthy ones only with MRCP; and 33 with possible biliary tract pathology, most of which had both endoscopes retrograde cholangiopancreatogaphy (ERCP) and MRCP: All MRCP's were performed with a 3D - TSE sequence with T2 - weighting, using coronal thin contiguous slices and reconstructions with maximal intensity projections (MIP) on different planes. MRCP allows an excellent anatomic depiction of the biliary tree and pancreatic duct

  12. The Standardized Histogram Shift of T2 Magnetic Resonance Image (MRI) Signal Intensities of Nephroblastoma Does Not Predict Histopathological Diagnostic Information

    OpenAIRE

    M?ller, Sabine; David, Ruslan; Marias, Kostas; Graf, Norbert

    2015-01-01

    The objective of this study is to assess standardized histograms of signal intensities of T2-weighted magnetic resonance image (MRI) modality before and after preoperative chemotherapy for nephroblastoma (Wilms? tumor). All analyzed patients are enrolled in the International Society of Paediatric Oncology (SIOP) 2001/GPOH trial.1 The question to be answered is whether the comparison of the histograms can add new knowledge by comparing them with the histology of the tumor after preoperative ch...

  13. Magnetic resonance imaging of lateral epicondylitis of the elbow with a 0.2-T dedicated system

    Energy Technology Data Exchange (ETDEWEB)

    Steinborn, M.; Heuck, A.; Bonel, H.; Reiser, M. [Department of Radiology, Ludwig Maximilians Univ., Muenchen (Germany); Jessel, C. [Department of Orthopedics, Ludwig Maximilians Univ., Muenchen (Germany)

    1999-09-01

    The purpose of this study was to evaluate MR imaging findings of the common extensor tendon in patients with lateral epicondylitis and asymptomatic volunteers studied on a 0.2-T dedicated system. In 23 patients (age range 29-58 years, mean age 47 years) with clinical symptoms of lateral epicondylitis MR imaging was performed using T1-, T2- and contrast-enhanced T1-weighted spin-echo sequences. In addition, the elbows of seven healthy volunteers (age range 22-29 years, mean age 25 years) and the symptom-free contralateral elbow of 11 of the 23 patients (age range 29-58 years, mean age 47 years) were studied as controls. Five patients were surgically treated after the MR examination and the results of histopathology were correlated with MR findings. Of the patients, 95.6 % showed intratendinous signal intensity changes on T1-weighted images on the symptomatic side. In 69.6 % signal alterations were observed on T2-weighted sequences and in 56.5 % an intratendinous contrast enhancement was present. Histopathology showed fibrovascular proliferation and fatty degeneration in patients with distinct signal intensity changes and contrast enhancement. Patients with only minor signal intensity changes on T1- and T2-weighted sequences and no contrast enhancement demonstrated fibrosclerotic degeneration and intratendinous cartilage formation in histopathology. The contralateral elbow showed signal intensity changes in 6 of 11 (54.5 %) cases on T1-weighted images and in 3 of 11 (27.3 %) on T2-weighted images. In the group of healthy volunteers minor signal intensity changes of the common extensor tendon could be seen in only 1 case. In patients with lateral epicondylitis of the elbow the type and extent of pathologic changes within the common extensor tendon can be evaluated using a dedicated low-field MR system. On the basis of MR imaging findings a more specified therapy planning among the variety of treatment modalities can be achieved. (orig.) With 3 figs., 5 tabs., 15 refs.

  14. Magnetic resonance imaging of lateral epicondylitis of the elbow with a 0.2-T dedicated system

    International Nuclear Information System (INIS)

    Steinborn, M.; Heuck, A.; Bonel, H.; Reiser, M.; Jessel, C.

    1999-01-01

    The purpose of this study was to evaluate MR imaging findings of the common extensor tendon in patients with lateral epicondylitis and asymptomatic volunteers studied on a 0.2-T dedicated system. In 23 patients (age range 29-58 years, mean age 47 years) with clinical symptoms of lateral epicondylitis MR imaging was performed using T1-, T2- and contrast-enhanced T1-weighted spin-echo sequences. In addition, the elbows of seven healthy volunteers (age range 22-29 years, mean age 25 years) and the symptom-free contralateral elbow of 11 of the 23 patients (age range 29-58 years, mean age 47 years) were studied as controls. Five patients were surgically treated after the MR examination and the results of histopathology were correlated with MR findings. Of the patients, 95.6 % showed intratendinous signal intensity changes on T1-weighted images on the symptomatic side. In 69.6 % signal alterations were observed on T2-weighted sequences and in 56.5 % an intratendinous contrast enhancement was present. Histopathology showed fibrovascular proliferation and fatty degeneration in patients with distinct signal intensity changes and contrast enhancement. Patients with only minor signal intensity changes on T1- and T2-weighted sequences and no contrast enhancement demonstrated fibrosclerotic degeneration and intratendinous cartilage formation in histopathology. The contralateral elbow showed signal intensity changes in 6 of 11 (54.5 %) cases on T1-weighted images and in 3 of 11 (27.3 %) on T2-weighted images. In the group of healthy volunteers minor signal intensity changes of the common extensor tendon could be seen in only 1 case. In patients with lateral epicondylitis of the elbow the type and extent of pathologic changes within the common extensor tendon can be evaluated using a dedicated low-field MR system. On the basis of MR imaging findings a more specified therapy planning among the variety of treatment modalities can be achieved. (orig.)

  15. Assessment of magnetic resonance imaging of the breast using 0.5 T equipment

    International Nuclear Information System (INIS)

    Vilanova, J. C.; Barcelo, J.; Ferrer, J.; Castaner, F.; Miro, J.; Bassaganyas, R.; Viejo, N.; Albanell, J.; Villalon, M.

    2002-01-01

    To evaluate the efficacy of a magnetic resonance imaging technique of the breast using half-field equipment (0.5 T). We evaluated 191 magnetic resonance (MRI) studies made at our center from March 1998 to March 2001 using Signa Contour 0.5 T MRI equipment of General Electric. A dedicated bilateral breast made at fat saturation in the coronal plane before administering intravenous gadolinium, then 6 consecutive times after contrast administration. The sequence acquisition time was 70-90 seconds Image post processing included subtraction and analysis of the intensity/time curves in the region of interest (ROI) together with morphological evaluation of the lesion. Additional T2 weighted fast-spin-echo sequences (FSE T2), T1-weighted spin-echo (SE T1), FSE T2 with fat suppression, and STIR with water saturation were made for studies of breast implants. The clinical indications for MRI study of the breast were masses (n=79), microcalcifications (n=7), asymmetry (n=17), cases of indeterminate risk (n=7), postoperative control (n=51), and breast implants (n=25). The histological diagnosis was benign in 31 lesions and malignant in 73 lesions. The sensitivity specificity, and reliability of breast MRI were 93%, 81% and 89% respectively. Multicenter/multifocal neoplasms were found in 8% of patients and bilateral neoplasms in 2%. The therapeutic attitude was modified in 18% of the patients with breast cancer as a result of MRI findings. The results confirm the usefulness of MRI in the management of patients with breast cancer. Likewise, the present study demonstrated that breast MRI can be carried out with half-field equipment with the same reliability as with full-field equipment as long as specific breast cots are used rapid 3D sequences, and image processing with suitable software. (Author) 28 refs

  16. Detailed T1-Weighted Profiles from the Human Cortex Measured in Vivo at 3 Tesla MRI.

    Science.gov (United States)

    Ferguson, Bart; Petridou, Natalia; Fracasso, Alessio; van den Heuvel, Martijn P; Brouwer, Rachel M; Hulshoff Pol, Hilleke E; Kahn, René S; Mandl, René C W

    2018-04-01

    Studies into cortical thickness in psychiatric diseases based on T1-weighted MRI frequently report on aberrations in the cerebral cortex. Due to limitations in image resolution for studies conducted at conventional MRI field strengths (e.g. 3 Tesla (T)) this information cannot be used to establish which of the cortical layers may be implicated. Here we propose a new analysis method that computes one high-resolution average cortical profile per brain region extracting myeloarchitectural information from T1-weighted MRI scans that are routinely acquired at a conventional field strength. To assess this new method, we acquired standard T1-weighted scans at 3 T and compared them with state-of-the-art ultra-high resolution T1-weighted scans optimised for intracortical myelin contrast acquired at 7 T. Average cortical profiles were computed for seven different brain regions. Besides a qualitative comparison between the 3 T scans, 7 T scans, and results from literature, we tested if the results from dynamic time warping-based clustering are similar for the cortical profiles computed from 7 T and 3 T data. In addition, we quantitatively compared cortical profiles computed for V1, V2 and V7 for both 7 T and 3 T data using a priori information on their relative myelin concentration. Although qualitative comparisons show that at an individual level average profiles computed for 7 T have more pronounced features than 3 T profiles the results from the quantitative analyses suggest that average cortical profiles computed from T1-weighted scans acquired at 3 T indeed contain myeloarchitectural information similar to profiles computed from the scans acquired at 7 T. The proposed method therefore provides a step forward to study cortical myeloarchitecture in vivo at conventional magnetic field strength both in health and disease.

  17. Dynamic contrast-enhanced quantitative perfusion measurement of the brain using T-1-weighted MRI at 3T

    DEFF Research Database (Denmark)

    Larsson, H.B.W.; Hansen, A.E.; Berg, H.K.

    2008-01-01

    Purpose: To develop a method for the measurement of brain perfusion based on dynamic contrast-enhanced T-1-weighted MR imaging. Materials and Methods: Dynamic imaging of the first pass of a bolus of a paramagnetic contrast agent was performed using a 3T whole-body magnet and a T-1-weighted fast...... field echo sequence. The input function was obtained from the internal carotid artery. An initial T-1 measurement was performed in order to convert the MR signal to concentration of the contrast agent. Pixelwise and region of interest (ROI)based calculation of cerebral perfusion (CBF) was performed...... inside the infarct core was, 9 mL/100g/min in one of the stroke patients. The other stroke patient had postischemic hyperperfusion and CBF was 140 mL/100g/min. Conclusion: Absolute values of brain perfusion can be obtained using dynamic contrast-enhanced MRI. These values correspond,to expected values...

  18. Impact of the Parameter Variation on the Image Blurring in 3 T Magnetic Resonance Imaging: A Phantom Study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Woo; Lee, Sang Hoon; Kim, Nam Kug; Cho, Kyung Sik; Lee, Jin Seong [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    2013-04-15

    To evaluate the effects of the key imaging-parameter alterations on the four MR sequences in a phantom study. Magnetic resonance (MR) imaging was performed on a MR phantom with an 8-channel head coil by using a 3 T MR system. The images were obtained in the axial plane on four MR sequences [T1-weighted, T2-weighted, Proton-density, and 3 dimensional (3D) fast spin echo (FSE)] with controlled variations in the following key parameters: 1) echo train length (ETL), 2) repetition time (TR), and 3) echo time (TE). The image blurring was determined by the degree of the gradient angle; i.e., the blurring increased as the gradient angle decreases. The increasing ETL was observed to cause an increase in the image blurring on all pulse sequences with a statistical significance (p = 0.004) on the 3D FSE. Increasing the TR appeared to have no effect except a statistically significant decrease on the T1-weighted images (p = 0.011). Increasing TE showed no effect on the T1-weighted images (p = 0.932); however, it caused an increase of blurring on the proton density images (p = 0.016) as well as the T2-weighted images (p < 0.001), and a decrease on the 3D FSE (p = 0.001). To reduce the image blurring, short ETL and long TE for 3D FSE, long TR for T1-weighted images and short TE for proton-density and T2-weighted images should be applied.

  19. Fast FLAIR MR imaging finidngs of cerebral infarction : comparison with T2-weighted spin echo imaging

    International Nuclear Information System (INIS)

    Kong, Keun Young; Choi, Woo Suk; Kim, Eui Jong

    1997-01-01

    To evaluate the utility of FLAIR(Fluid Attenuated Inversion Recovery) MR imaging in cerebral infarction by comparing its results with those of T2-weighted spin-echo imaging. We retrospectively evaluated fast FLAIR images and conventional spin echo images of 82 patients (47 men and 20 women ; median age 60.9 years) with cerebral infarction. MR imaging used a 1.5T MR unit with conventional T2(TR 3900, TE 90) and fast FLAIR sequence (TR 8000, TE 105, TI 2400). We analysed the size of the main lesion and number of lesions, and discrimination between old and new lesions and between small infarction and perivascular space. When T2-weighted and FLAIR imaging were compared, the latter showed that the main lesion was larger in 38 cases (46%), similar in 38 (46%), and smaller in six (7%). The number of lesions was greater in 23 cases(28%), similar in 52 (63%), and fewer in seven (9%). FLAIR images discriminated between old and new lesions in 31 cases ; perivascular space and small infarotion were differentiated in eight cases, and CSF inflowing artifact was observed in 66 (80%). In the diagnosis of cerebral infaretion, fast FLAIR provides images that are equal or superior to T2-weighted images. The fast FLAIR sequence may therefore be used as a part of routine MR brain study in the diagnosis of cerebral infarction

  20. Artifact free T2*-weighted imaging at high spatial resolution using segmented EPI sequences

    International Nuclear Information System (INIS)

    Heiler, Patrick Michael; Schad, Lothar Rudi; Schmitter, Sebastian

    2010-01-01

    The aim of this work was the development of novel measurement techniques that acquire high resolution T2 * -weighted datasets in measurement times as short as possible without suffering from noticeable blurring and ghosting artifacts. Therefore, two new measurement techniques were developed that acquire a smoother k-space than generic multi shot echo planar imaging sequences. One is based on the principle of echo train shifting, the other on the reversed gradient method. Simulations and phantom measurements demonstrate that echo train shifting works properly and reduces artifacts in multi shot echo planar imaging. For maximum SNR-efficiency this technique was further improved by adding a second contrast. Both contrasts can be acquired within a prolongation in measurement time by a factor of 1.5, leading to an SNR increase by approximately √2. Furthermore it is demonstrated that the reversed gradient method remarkably reduces artifacts caused by a discontinuous k-space weighting. Assuming sequence parameters as feasible for fMRI experiments, artifact free T2 * -weighted images with a matrix size of 256 x 256 leading to an in-plane resolution in the submillimeter range can be obtained in about 2 s per slice. (orig.)

  1. Usefulness of fluid attenuated inversion recovery(FLAIR) image in mesial temporal sclerosis : comparison with turbo spin-echo T2-weighted image

    Energy Technology Data Exchange (ETDEWEB)

    Son, Seok Hyun; Chang, Seung Kuk; Eun, Choong Ki [Pusan Paik Hospital, Inje Univ. College of Medicine, Kimhae (Korea, Republic of)

    1999-12-01

    To determine the usefulness of fluid attenuated inversion recovery(FLAIR) imaging for the in detection of high signal intensity of hippocampus or amygdala in mesial temporal sclerosis (MTS), compared with that of turbo spin-echo T2-weighted imaging. Two neuroradiologists independently analyzed randomly mixed MR images of 20 lesions of 17 patients in whom MTS had been diagnosed, and ten normal controls. All subjects underwent both who performed both FLAIR and turbo spin-echo T2-weighted imaging, in a blind fashion. In order to determine hippocampal morphology, oblique coronal images perpendicular to the long axis of the hippocampus were obtained. The detection rate of high signal intensity in hippocampus or amygdala, the radiologists' preferred imaging sequence, and intersubject consistency of detection were evaluated. Signal intensity in hippocampus or amygdala was considered high if substantially higher than signal intensity in the cortex of adjacent temporo-parietal lobe. In all normal controls, FLAIR and spin-echo T2-weighted images showed normal signal intensity in hippocampus or amygdala. In MTS, the mean detection rate of high signal intensity in hippocampus or amygdala, as seen on FLAIR images was 93%, compared with 43% on spin-echo T2-weighted images. In all cases in which signal intensity on FLAIR images was normal, signal intensity on spin-echo T2-weighted images was also normal. The radiologists preferred the contrast properties of FLAIR to those of spin-echo T2-weighted images. In the diagnosis of MTS using MRI, FLAIR images are more useful for the detection of high signal intensity of hippocampus or amygdala than are spin-echo T2-weighted images. In the diagnosis of MTS, FLAIR imaging is therefore a suitable alternative to spin-echo T2-weighted imaging.

  2. Usefulness of fluid attenuated inversion recovery(FLAIR) image in mesial temporal sclerosis : comparison with turbo spin-echo T2-weighted image

    International Nuclear Information System (INIS)

    Son, Seok Hyun; Chang, Seung Kuk; Eun, Choong Ki

    1999-01-01

    To determine the usefulness of fluid attenuated inversion recovery(FLAIR) imaging for the in detection of high signal intensity of hippocampus or amygdala in mesial temporal sclerosis (MTS), compared with that of turbo spin-echo T2-weighted imaging. Two neuroradiologists independently analyzed randomly mixed MR images of 20 lesions of 17 patients in whom MTS had been diagnosed, and ten normal controls. All subjects underwent both who performed both FLAIR and turbo spin-echo T2-weighted imaging, in a blind fashion. In order to determine hippocampal morphology, oblique coronal images perpendicular to the long axis of the hippocampus were obtained. The detection rate of high signal intensity in hippocampus or amygdala, the radiologists' preferred imaging sequence, and intersubject consistency of detection were evaluated. Signal intensity in hippocampus or amygdala was considered high if substantially higher than signal intensity in the cortex of adjacent temporo-parietal lobe. In all normal controls, FLAIR and spin-echo T2-weighted images showed normal signal intensity in hippocampus or amygdala. In MTS, the mean detection rate of high signal intensity in hippocampus or amygdala, as seen on FLAIR images was 93%, compared with 43% on spin-echo T2-weighted images. In all cases in which signal intensity on FLAIR images was normal, signal intensity on spin-echo T2-weighted images was also normal. The radiologists preferred the contrast properties of FLAIR to those of spin-echo T2-weighted images. In the diagnosis of MTS using MRI, FLAIR images are more useful for the detection of high signal intensity of hippocampus or amygdala than are spin-echo T2-weighted images. In the diagnosis of MTS, FLAIR imaging is therefore a suitable alternative to spin-echo T2-weighted imaging

  3. Mn-DPDP enhanced T1-weighted magnetic resonance cholangiography: usefulness in the diagnosis and roadmap for the treatment of intrahepatic choIedochoIithiasis

    International Nuclear Information System (INIS)

    Park, Mi Suk; Kim, Ki Whang; Yu, Jeong Sik; Kim, Myeong Jin; Lee, Jong Tae; Yoo, Hyung Sik; Kim, Kyoung Won; Kim, Tae Kyoung; Ha, Hyun Kwon

    2004-01-01

    To assess the preliminary findings of Mn-enhanced T1-weighted MR cholangiography for the evaluation of intrahepatic choledocholithiasis. Seven patients with recurrent pyogenic cholangitis underwent conventional heavily T2-weighted and manganese-enhanced T1-weighted MR cholangiography. For the former, the two reviewers focused on intrahepatic ductal dilatation, calculi, and stricture; and for the latter, ductal enhancement. In seven patients, 13 diseased segments were depicted and intrahepatic bile ductal dilatation was present in all 13 of these in all seven patients. Calculi were present in eight segments in six patients, and stricture in four segments in three patients. Of the 13 diseased segmental ducts, six were seen at manganese-enhanced imaging to be filled with contrast material, suggesting a functioning bile duct. Combined T2-weighted and mangafodipir trisodium-enhanced T1-weighted MR cholangiography provides both anatomic detail and functional detail of the biliary system. Combined MR cholangiography is useful for the evaluation of intrahepatic choledocholithiasis, demonstrating the stricture and function of the segmental ducts involved

  4. Value of T2-weighted MR imaging in differentiating low-fat renal angiomyolipomas from other renal tumors

    International Nuclear Information System (INIS)

    Choi, Hyuck Jae; Kim, Jeong Kon; Kim, Mi-Hyun; Cho, Kyoung-Sik; Ahn, Hanjong; Kim, Choung-Soo

    2011-01-01

    Background: Accurate preoperative diagnosis of fat scanty angiomyolipomas is an important clinical issue. By evaluating the low signal intensity of angiomyolipomas in MR T2-weighted images the diagnostic accuracy can be elevated. Purpose: To retrospectively assess the usefulness of T2-weighted MR imaging for differentiating low-fat angiomyolipomas (AMLs) from other renal tumors. Material and Methods: We retrospectively evaluated 71 patients with surgically proven renal masses (10 AMLs, 57 renal cell carcinomas [RCCs], and four oncocytomas), all of which showed no visible fat as well as gradual enhancement patterns on contrast-enhanced CT. Signal intensity was measured in each renal mass and in the spleen on T2-weighted images, and each signal intensity ratio (SIR) was calculated; SIR values were then compared in the AML and non-AML groups. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic performance of the two parameters for differentiating the two groups. Results: The SIR values (77 ± 24% vs. 162 ± 79%, p = 0.002) were significantly lower in the AML than in the non-AML group. The area under the ROC curve was 0.926 for SIR. The sensitivity and specificity in the diagnosis of AMLs were 90% and 90.2%, using SIR cut-off of 92.5%. Conclusion: Signal intensity measurements on T2-weighted MR images can differentiate AML from non-AML in the kidney

  5. SPAMM, cine phase contrast imaging and fast spin-echo T2-weighted imaging in the study of intracranial cerebrospinal fluid (CSF) flow

    International Nuclear Information System (INIS)

    Connor, S.E.J.; O'Gorman, R.; Summers, P.; Simmons, A.; Moore, E.M.; Chandler, C.; Jarosz, J.M.

    2001-01-01

    AIM: To compare the qualitative assessment of cerebrospinal fluid (CSF) flow using a SPAMM (spatial modulation of magnetization) technique with cine phase contrast images (cine PC) and fast spin echo (FSE) T2-weighted images. MATERIALS AND METHODS: SPAMM, PC and T2-weighted sequences were performed on 22 occasions in 19 patients. Eleven of the studies were performed following a neuroendoscopic third ventriculostomy (NTV), and in these cases, the success of the NTV was determined by clinical follow-up. Two observers used consensus to grade the presence of CSF flow at nine different sites for each study. RESULTS: At 14 of the 178 matched sites, which could be assessed by both SPAMM and cine PC, SPAMM CSF flow grade was higher than that of cine PC. At a further 14/178 matched sites, the cine PC grade was higher than that of SPAMM. There was definite CSF flow at 113/182 (62%) of all the cine PC sites assessed, and 110/181 (61%) of all SPAMM sites assessed whilst 108/198 (54%) of FSE T2-weighted image sites demonstrated flow voids. Cine PC grades were higher than SPAMM at the cerebral aqueduct (P < 0.05, Wilcoxon sign rank test). Definite CSF flow within the anterior third ventricle was present in 4/5 (SPAMM) and 3/5 (cine PC) successful NTVs, 0/2 (SPAMM and cine PC) unsuccessful NTVs and 1/10 (SPAMM and cine PC) patients without NTV. CONCLUSION: SPAMM provides a comparable assessment of intracranial CSF flow to that of cine phase contrast imaging at all CSF sites except the cerebral aqueduct. Connor, S.E.J. et al. (2001)

  6. In vivo T2* weighted MRI visualizes cardiac lesions in murine models of acute and chronic viral myocarditis.

    Directory of Open Access Journals (Sweden)

    Xavier Helluy

    Full Text Available Acute and chronic forms of myocarditis are mainly induced by virus infections. As a consequence of myocardial damage and inflammation dilated cardiomyopathy and chronic heart failure may develop. The gold standard for the diagnosis of myocarditis is endomyocardial biopsies which are required to determine the etiopathogenesis of cardiac inflammatory processes. However, new non-invasive MRI techniques hold great potential in visualizing cardiac non-ischemic inflammatory lesions at high spatial resolution, which could improve the investigation of the pathophysiology of viral myocarditis.Here we present the discovery of a novel endogenous T2* MRI contrast of myocardial lesions in murine models of acute and chronic CVB3 myocarditis. The evaluation of infected hearts ex vivo and in vivo by 3D T2w and T2*w MRI allowed direct localization of virus-induced myocardial lesions without any MRI tracer or contrast agent. T2*w weighted MRI is able to detect both small cardiac lesions of acute myocarditis and larger necrotic areas at later stages of chronic myocarditis, which was confirmed by spatial correlation of MRI hypointensity in myocardium with myocardial lesions histologically. Additional in vivo and ex vivo MRI analysis proved that the contrast mechanism was due to a strong paramagnetic tissue alteration in the vicinity of myocardial lesions, effectively pointing towards iron deposits as the primary contributor of contrast. The evaluation of the biological origin of the MR contrast by specific histological staining and transmission electron microscopy revealed that impaired iron metabolism primarily in mitochondria caused iron deposits within necrotic myocytes, which induces strong magnetic susceptibility in myocardial lesions and results in strong T2* contrast.This T2*w MRI technique provides a fast and sensitive diagnostic tool to determine the patterns and the severity of acute and chronic enteroviral myocarditis and the precise localization of

  7. Whole-brain intracranial vessel wall imaging at 3 Tesla using cerebrospinal fluid-attenuated T1-weighted 3D turbo spin echo.

    Science.gov (United States)

    Fan, Zhaoyang; Yang, Qi; Deng, Zixin; Li, Yuxia; Bi, Xiaoming; Song, Shlee; Li, Debiao

    2017-03-01

    Although three-dimensional (3D) turbo spin echo (TSE) with variable flip angles has proven to be useful for intracranial vessel wall imaging, it is associated with inadequate suppression of cerebrospinal fluid (CSF) signals and limited spatial coverage at 3 Tesla (T). This work aimed to modify the sequence and develop a protocol to achieve whole-brain, CSF-attenuated T 1 -weighted vessel wall imaging. Nonselective excitation and a flip-down radiofrequency pulse module were incorporated into a commercial 3D TSE sequence. A protocol based on the sequence was designed to achieve T 1 -weighted vessel wall imaging with whole-brain spatial coverage, enhanced CSF-signal suppression, and isotropic 0.5-mm resolution. Human volunteer and pilot patient studies were performed to qualitatively and quantitatively demonstrate the advantages of the sequence. Compared with the original sequence, the modified sequence significantly improved the T 1 -weighted image contrast score (2.07 ± 0.19 versus 3.00 ± 0.00, P = 0.011), vessel wall-to-CSF contrast ratio (0.14 ± 0.16 versus 0.52 ± 0.30, P = 0.007) and contrast-to-noise ratio (1.69 ± 2.18 versus 4.26 ± 2.30, P = 0.022). Significant improvement in vessel wall outer boundary sharpness was observed in several major arterial segments. The new 3D TSE sequence allows for high-quality T 1 -weighted intracranial vessel wall imaging at 3 T. It may potentially aid in depicting small arteries and revealing T 1 -mediated high-signal wall abnormalities. Magn Reson Med 77:1142-1150, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  8. Prediction of low birth weight: the placental T2* estimated by MRI versus the uterine artery pulsatility index

    DEFF Research Database (Denmark)

    Sinding, Marianne Munk; Peters, David Alberg; Frøkjær, Jens Brøndum

    (MRI) variable T2* reflects the placental oxygenation and thereby placental function. Therefore, we aimed to evaluate the performance of placental T2* in the prediction of low birth weight using the uterine artery (UtA) pulsatility index (PI) as gold standard. Methods: The study population......CONTROL ID: 2516296 ABSTRACT FINAL ID: P22.05 TITLE: Prediction of low birth weight: the placental T2* estimated by MRI versus the uterine artery pulsatility index AUTHORS (FIRST NAME, LAST NAME): Marianne Sinding1, David Peters2, Jens B. Frøkjær3, 4, Ole B. Christiansen1, 4, Astrid Petersen5...... had an EFW T2* was measured by MRI at 1.5T. A gradient recalled echo MRI sequence with readout at 16 echo times was used, and the placental T2* value was obtained by fitting the signal intensity as a function of the echo times...

  9. Dual-mode T_1 and T_2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application

    International Nuclear Information System (INIS)

    Tegafaw, Tirusew; Xu, Wenlong; Ahmad, Md Wasi; Lee, Gang Ho; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong

    2015-01-01

    A new type of dual-mode T_1 and T_2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd"3"+ ("8S_7_/_2) plays an important role in T_1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy"3"+ ("6H_1_5_/_2) has the potential to be used in T_2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy_2O_3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd"3"+ and Dy"3"+ and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T_1 and T_2 MRI contrast agent was investigated in vitro and in vivo. The D-glucuronic acid coated GDO nanoparticles (d_a_v_g = 1.0 nm) showed large r_1 and r_2 values (r_2/r_1 ≈ 6.6) and as a result clear dose-dependent contrast enhancements in R_1 and R_2 map images. Finally, the dual-mode imaging capability of the nanoparticles was confirmed by obtaining in vivo T_1 and T_2 MR images. (paper)

  10. Improved longitudinal length accuracy of gross tumor volume delineation with diffusion weighted magnetic resonance imaging for esophageal squamous cell carcinoma

    International Nuclear Information System (INIS)

    Hou, Dong-Liang; Shi, Gao-Feng; Gao, Xian-Shu; Asaumi, Junichi; Li, Xue-Ying; Liu, Hui; Yao, Chen; Chang, Joe Y

    2013-01-01

    To analyze the longitudinal length accuracy of gross tumor volume (GTV) delineation with diffusion weighted magnetic resonance imaging for esophageal squamous cell carcinoma (SCC). Forty-two patients from December 2011 to June 2012 with esophageal SCC who underwent radical surgery were analyzed. Routine computed tomography (CT) scan, T2-weighted MRI and diffusion weighted magnetic resonance imaging (DWI) were employed before surgery. Diffusion-sensitive gradient b-values were taken at 400, 600, and 800 s/mm 2 . Gross tumor volumes (GTV) were delineated using CT, T2-weighted MRI and DWI on different b-value images. GTV longitude length measured using the imaging modalities listed above was compared with pathologic lesion length to determine the most accurate imaging modality. CMS Xio radiotherapy planning system was used to fuse DWI scans and CT images to investigate the possibility of delineating GTV on fused images. The differences between the GTV length according to CT, T2-weighted MRI and pathology were 3.63 ± 12.06 mm and 3.46 ± 11.41 mm, respectively. When the diffusion-sensitive gradient b-value was 400, 600, and 800 s/mm 2 , the differences between the GTV length using DWI and pathology were 0.73 ± 6.09 mm, -0.54 ± 6.03 mm and −1.58 ± 5.71 mm, respectively. DWI scans and CT images were fused accurately using the radiotherapy planning system. GTV margins were depicted clearly on fused images. DWI displays esophageal SCC lengths most precisely when compared with CT or regular MRI. DWI scans fused with CT images can be used to improve accuracy to delineate GTV in esophageal SCC

  11. The magnet system of the Tokamak T-15 upgrade

    International Nuclear Information System (INIS)

    Khvostenko, P.P.; Azizov, E.A.; Alfimov, D.E.; Belyakov, V.A.; Bondarchuk, E.N.; Chudnovsky, A.N.; Dokuka, V.N.; Kavin, A.A.; Khayrutdinov, R.R.; Khokhlov, M.V.; Kitaev, B.A.; Krasnov, S.V.; Maximova, I.I.; Labusov, A.N.; Lukash, V.E.; Mineev, A.B.; Muratov, V.P.

    2015-01-01

    Highlights: • T-15U project is the initial technical base for creating fusion neutron sources. • Magnet system of T-15U will confine the hot plasma in the divertor configuration. • Toroidal magnetic field at the plasma axis is 2 T. • T-15U should begin operations in 2016. - Abstract: Presently, the Tokamak T-15 is being upgraded. The magnet system of the Tokamak T-15 upgrade will obtain and confine the hot plasma in the divertor configuration. Plasma parameters are a major radius of 1.48 m, a minor radius of 0.67 m, an elongation of 1.7–1.9 and a triangularity of 0.3–0.4. The magnet system includes the toroidal winding and the poloidal magnet system. The poloidal magnet system generates the divertor with single null and double null magnetic configurations. The power supply system provides the necessary current scenarios in the windings of the magnet system. All elements of the magnet system will be manufactured by the end of 2015. The Tokamak T-15 upgrade should begin operations in 2016.

  12. The magnet system of the Tokamak T-15 upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Khvostenko, P.P., E-mail: ppkhvost@rambler.ru [National Research Centre ‘Kurchatov Institute’, Institute of Tokamak Physics, Kurchatov sq. 1, 123182 Moscow (Russian Federation); Azizov, E.A.; Alfimov, D.E. [National Research Centre ‘Kurchatov Institute’, Institute of Tokamak Physics, Kurchatov sq. 1, 123182 Moscow (Russian Federation); Belyakov, V.A.; Bondarchuk, E.N. [Joint Stock Company “D.V. Efremov Institute of Electrophysical Apparatus”, Metallostroy, 196641 St. Petersburg (Russian Federation); Chudnovsky, A.N.; Dokuka, V.N. [National Research Centre ‘Kurchatov Institute’, Institute of Tokamak Physics, Kurchatov sq. 1, 123182 Moscow (Russian Federation); Kavin, A.A. [Joint Stock Company “D.V. Efremov Institute of Electrophysical Apparatus”, Metallostroy, 196641 St. Petersburg (Russian Federation); Khayrutdinov, R.R. [National Research Centre ‘Kurchatov Institute’, Institute of Tokamak Physics, Kurchatov sq. 1, 123182 Moscow (Russian Federation); Khokhlov, M.V.; Kitaev, B.A.; Krasnov, S.V.; Maximova, I.I.; Labusov, A.N. [Joint Stock Company “D.V. Efremov Institute of Electrophysical Apparatus”, Metallostroy, 196641 St. Petersburg (Russian Federation); Lukash, V.E. [National Research Centre ‘Kurchatov Institute’, Institute of Tokamak Physics, Kurchatov sq. 1, 123182 Moscow (Russian Federation); Mineev, A.B.; Muratov, V.P. [Joint Stock Company “D.V. Efremov Institute of Electrophysical Apparatus”, Metallostroy, 196641 St. Petersburg (Russian Federation); and others

    2015-10-15

    Highlights: • T-15U project is the initial technical base for creating fusion neutron sources. • Magnet system of T-15U will confine the hot plasma in the divertor configuration. • Toroidal magnetic field at the plasma axis is 2 T. • T-15U should begin operations in 2016. - Abstract: Presently, the Tokamak T-15 is being upgraded. The magnet system of the Tokamak T-15 upgrade will obtain and confine the hot plasma in the divertor configuration. Plasma parameters are a major radius of 1.48 m, a minor radius of 0.67 m, an elongation of 1.7–1.9 and a triangularity of 0.3–0.4. The magnet system includes the toroidal winding and the poloidal magnet system. The poloidal magnet system generates the divertor with single null and double null magnetic configurations. The power supply system provides the necessary current scenarios in the windings of the magnet system. All elements of the magnet system will be manufactured by the end of 2015. The Tokamak T-15 upgrade should begin operations in 2016.

  13. Assessment of brain maturation in the preterm infants using diffusion tensor imaging (DTI) and enhanced T2 star weighted angiography (ESWAN)

    International Nuclear Information System (INIS)

    Ling, Xueying; Tang, Wen; Liu, Guosheng; Huang, Li; Li, Bingxiao; Li, Xiaofei; Liu, Sirun; Xu, Jing

    2013-01-01

    Purpose: To assess the brain maturation of preterm infants using diffusion tensor imaging (DTI) and enhanced T2 star weighted angiography (ESWAN). Materials and methods: Conventional magnetic resonance imaging (MRI), DTI and ESWAN were performed in 60 preterm infants and 21 term controls. 60 preterm infants were subgrouped to two groups according to the age at imaging: before and at term-equivalent age (TEA). Fractional anisotropy (FA), apparent diffusion coefficient (ADC) map from DTI, T 2 * and R 2 * maps from ESWAN were post-processed at an off-line workstation. The values of FA, ADC, T 2 * and R 2 * from the posterior limb of internal capsule (PLIC), frontal white matter (FWM), occipital white matter (OWM) and lentiform nuclei (LN) were determined. These parameters were compared between preterm and term infants. Correlations of DTI and ESWAN parameters with the gestational age, postmenstrual age and postnatal age were analyzed. Results: ADCs of FWM, OWM and LN, and T 2 * values of the PLIC and LN were higher in the preterm infants at TEA compared with the term controls. The correlations were existed between the postmenstrual age and the values of FA, ADC, T 2 *, R 2 * from the PLIC, values of ADC, T 2 *, R 2 * from the LN, T 2 * value from the OWM. The correlations were also found between the postnatal age and the values of FA, ADC, T 2 * from the PLIC, and T 2 * value from the LN. Conclusion: The maturity of preterm brain around TEA was different from that of term controls and appeared to be independent of the prematurity at birth. T 2 * was one of valuable indices to evaluate brain maturation in preterm infants

  14. Assessment of brain maturation in the preterm infants using diffusion tensor imaging (DTI) and enhanced T2 star weighted angiography (ESWAN)

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Xueying, E-mail: lingxuey@163.com [Department of Medical Imaging Center, the First Affiliated Hospital, Jinan University, Guangzhou (China); Tang, Wen [Department of Medical Imaging Center, the First Affiliated Hospital, Jinan University, Guangzhou (China); Liu, Guosheng [Neonatal Intensive Care Unit, the First Affiliated Hospital, Jinan University, Guangzhou (China); Huang, Li [Department of Medical Imaging Center, the First Affiliated Hospital, Jinan University, Guangzhou (China); Li, Bingxiao [Neonatal Intensive Care Unit, the First Affiliated Hospital, Jinan University, Guangzhou (China); Li, Xiaofei; Liu, Sirun [Department of Medical Imaging Center, the First Affiliated Hospital, Jinan University, Guangzhou (China); Xu, Jing [Neonatal Intensive Care Unit, the First Affiliated Hospital, Jinan University, Guangzhou (China)

    2013-09-15

    Purpose: To assess the brain maturation of preterm infants using diffusion tensor imaging (DTI) and enhanced T2 star weighted angiography (ESWAN). Materials and methods: Conventional magnetic resonance imaging (MRI), DTI and ESWAN were performed in 60 preterm infants and 21 term controls. 60 preterm infants were subgrouped to two groups according to the age at imaging: before and at term-equivalent age (TEA). Fractional anisotropy (FA), apparent diffusion coefficient (ADC) map from DTI, T{sub 2}* and R{sub 2}* maps from ESWAN were post-processed at an off-line workstation. The values of FA, ADC, T{sub 2}* and R{sub 2}* from the posterior limb of internal capsule (PLIC), frontal white matter (FWM), occipital white matter (OWM) and lentiform nuclei (LN) were determined. These parameters were compared between preterm and term infants. Correlations of DTI and ESWAN parameters with the gestational age, postmenstrual age and postnatal age were analyzed. Results: ADCs of FWM, OWM and LN, and T{sub 2}* values of the PLIC and LN were higher in the preterm infants at TEA compared with the term controls. The correlations were existed between the postmenstrual age and the values of FA, ADC, T{sub 2}*, R{sub 2}* from the PLIC, values of ADC, T{sub 2}*, R{sub 2}* from the LN, T{sub 2}* value from the OWM. The correlations were also found between the postnatal age and the values of FA, ADC, T{sub 2}* from the PLIC, and T{sub 2}* value from the LN. Conclusion: The maturity of preterm brain around TEA was different from that of term controls and appeared to be independent of the prematurity at birth. T{sub 2}* was one of valuable indices to evaluate brain maturation in preterm infants.

  15. The Usefulness of Fast-Spin-Echo T2-Weighted MR Imaging in Nutcracker Syndrome: a Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Heong Leng; Chen, Matt Chiung Yu; Wu, Cgek Siung; Fu, Kuo An; Lin, Cheng Hao [Yuan' s General Hospital, Kaohsiung (China); Weng, Mei Jui; Liang, Huei Lung; Pan, Huay Ben [National Yang-Ming University, Taipei (Korea, Republic of)

    2010-06-15

    Nutcracker syndrome occurs when the left renal vein (LRV) is compressed between the superior mesenteric artery and the aorta, and this syndrome is often characterized by venous hypertension and related pathologies. However, invasive studies such as phlebography and measuring the reno-caval pressure gradient should be performed to identify venous hypertension. Here we present a case of Nutcracker syndrome where the LRV and intra-renal varicosities appeared homogeneously hyperintense on magnetic resonance (MR) fast-spin-echo T2- weighted imaging, which suggested markedly stagnant intravenous blood flow and the presence of venous hypertension. The patient was diagnosed and treated without obtaining the reno-caval pressure gradient. The discomfort of the patient lessened after treatment. Furthermore, on follow-up evaluation, the LRV displayed a signal void, and this was suggestive of a restoration of the normal LRV flow and a decrease in LRV pressure.

  16. Hyperintense globus pallidus on T1-weighted MR imaging in acute kernicterus: is it common or rare?

    Energy Technology Data Exchange (ETDEWEB)

    Coskun, Abdulhakim; Yikilmaz, Ali; Karahan, Okkes Ibrahim; Manav, Ali [Erciyes University Medical School, Department of Radiology, Kayseri (Turkey); Kumandas, Sefer [Erciyes University Medical School, Department of Neuropediatry, Kayseri (Turkey); Akcakus, Mustafa [Erciyes University Medical School, Department of Neonatalogy, Kayseri (Turkey)

    2005-06-01

    Globus pallidus involvement is a well-known magnetic resonance (MR) imaging finding of acute kernicterus. However, it is not clear how early the involvement of globus pallidus occurs and whether or not it is seen in every case. Therefore, we aimed to investigate the globus pallidus involvement in 13 neonates with acute kernicterus by MR imaging. Thirteen neonates who were admitted with jaundice, encephalopathy and indirect hyperbilirubinemia (mean, 37.0 mg/dl) were prospectively evaluated with cranial MR imaging. Pathological signal changes were noted concerning the globus pallidus. Eight of the 13 patients demonstrated bilateral, symmetric increased signal intensity in the globus pallidus on T1-weighted MR imaging. These lesions were not apparent on T2-weighted images. Multiple parenchymal punctuate T1 hyperintense lesions were detected in one patient without globus pallidus involvement. This appearance was consistent with hemorrhage. The MR imaging findings of the other four patients showed no evidence of abnormality. The symmetric involvement of globus pallidus seen as hyperintense on T1-weighted MR imaging is a common and characteristic finding of acute kernicterus. (orig.)

  17. Hyperintense globus pallidus on T1-weighted MR imaging in acute kernicterus: is it common or rare?

    International Nuclear Information System (INIS)

    Coskun, Abdulhakim; Yikilmaz, Ali; Karahan, Okkes Ibrahim; Manav, Ali; Kumandas, Sefer; Akcakus, Mustafa

    2005-01-01

    Globus pallidus involvement is a well-known magnetic resonance (MR) imaging finding of acute kernicterus. However, it is not clear how early the involvement of globus pallidus occurs and whether or not it is seen in every case. Therefore, we aimed to investigate the globus pallidus involvement in 13 neonates with acute kernicterus by MR imaging. Thirteen neonates who were admitted with jaundice, encephalopathy and indirect hyperbilirubinemia (mean, 37.0 mg/dl) were prospectively evaluated with cranial MR imaging. Pathological signal changes were noted concerning the globus pallidus. Eight of the 13 patients demonstrated bilateral, symmetric increased signal intensity in the globus pallidus on T1-weighted MR imaging. These lesions were not apparent on T2-weighted images. Multiple parenchymal punctuate T1 hyperintense lesions were detected in one patient without globus pallidus involvement. This appearance was consistent with hemorrhage. The MR imaging findings of the other four patients showed no evidence of abnormality. The symmetric involvement of globus pallidus seen as hyperintense on T1-weighted MR imaging is a common and characteristic finding of acute kernicterus. (orig.)

  18. Effect of biological characteristics of different types of uterine fibroids, as assessed with T2-weighted magnetic resonance imaging, on ultrasound-guided high-intensity focused ultrasound ablation.

    Science.gov (United States)

    Zhao, Wen-Peng; Chen, Jin-Yun; Chen, Wen-Zhi

    2015-02-01

    The aims of this study were to assess the effects of the biological characteristics of different types of uterine fibroids, as assessed with T2-weighted magnetic resonance imaging (MRI), on ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation. Thirty-five patients with 39 symptomatic uterine fibroids who underwent myomectomy or hysterectomy were enrolled. Before surgery, the uterine fibroids were subdivided into hypo-intense, iso-intense, heterogeneous hyper-intense and homogeneous hyper-intense categories based on signal intensity on T2-weighted MRI. Tissue density and moisture content were determined in post-operative samples and normal uterine tissue, the isolated uterine fibroids were subjected to USgHIFU, and the extent of ablation was measured using triphenyltetrazolium chloride. Hematoxylin and eosin staining and sirius red staining were undertaken to investigate the organizational structure of the uterine fibroids. Estrogen and progesterone receptor expression was assayed via immunohistochemical staining. The mean diameter of uterine fibroids was 6.9 ± 2.8 cm. For all uterine fibroids, the average density and moisture content were 10.7 ± 0.7 mg/mL and 75.7 ± 2.4%, respectively; and for the homogeneous hyper-intense fibroids, 10.3 ± 0.5 mg/mL and 76.6 ± 2.3%. The latter subgroup had lower density and higher moisture content compared with the other subgroups. After USgHIFU treatment, the extent of ablation of the hyper-intense fibroids was 102.7 ± 42.1 mm(2), which was significantly less than those of the hypo-intense and heterogeneous hyper-intense fibroids. Hematoxylin and eosin staining and sirius red staining revealed that the homogeneous hyper-intense fibroids had sparse collagen fibers and abundant cells. Immunohistochemistry results revealed that estrogen and progesterone receptors were highly expressed in the homogeneous hyper-intense fibroids. This study revealed that lower density, higher moisture content, sparse collagen

  19. Topographical Variation of Human Femoral Articular Cartilage Thickness, T1rho and T2 Relaxation Times Is Related to Local Loading during Walking.

    Science.gov (United States)

    Van Rossom, Sam; Wesseling, Mariska; Van Assche, Dieter; Jonkers, Ilse

    2018-01-01

    Objective Early detection of degenerative changes in the cartilage matrix composition is essential for evaluating early interventions that slow down osteoarthritis (OA) initiation. T1rho and T2 relaxation times were found to be effective for detecting early changes in proteoglycan and collagen content. To use these magnetic resonance imaging (MRI) methods, it is important to document the topographical variation in cartilage thickness, T1rho and T2 relaxation times in a healthy population. As OA is partially mechanically driven, the relation between these MRI-based parameters and localized mechanical loading during walking was investigated. Design MR images were acquired in 14 healthy adults and cartilage thickness and T1rho and T2 relaxation times were determined. Experimental gait data was collected and processed using musculoskeletal modeling to identify weight-bearing zones and estimate the contact force impulse during gait. Variation of the cartilage properties (i.e., thickness, T1rho, and T2) over the femoral cartilage was analyzed and compared between the weight-bearing and non-weight-bearing zone of the medial and lateral condyle as well as the trochlea. Results Medial condyle cartilage thickness was correlated to the contact force impulse ( r = 0.78). Lower T1rho, indicating increased proteoglycan content, was found in the medial weight-bearing zone. T2 was higher in all weight-bearing zones compared with the non-weight-bearing zones, indicating lower relative collagen content. Conclusions The current results suggest that medial condyle cartilage is adapted as a long-term protective response to localized loading during a frequently performed task and that the weight-bearing zone of the medial condyle has superior weight bearing capacities compared with the non-weight-bearing zones.

  20. Low-Molecular-Weight Iron Chelates May Be an Alternative to Gadolinium-based Contrast Agents for T1-weighted Contrast-enhanced MR Imaging.

    Science.gov (United States)

    Boehm-Sturm, Philipp; Haeckel, Akvile; Hauptmann, Ralf; Mueller, Susanne; Kuhl, Christiane K; Schellenberger, Eyk A

    2018-02-01

    Purpose To synthesize two low-molecular-weight iron chelates and compare their T1 contrast effects with those of a commercial gadolinium-based contrast agent for their applicability in dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging. Materials and Methods The animal experiments were approved by the local ethics committee. Two previously described iron (Fe) chelates of pentetic acid (Fe-DTPA) and of trans-cyclohexane diamine tetraacetic acid (Fe-tCDTA) were synthesized with stability constants several orders of magnitude higher than those of gadolinium-based contrast agents. The T1 contrast effects of the two chelates were compared with those of gadopentetate dimeglumine in blood serum phantoms at 1.5 T, 3 T, and 7 T. For in vivo studies, a human breast cancer cell line (MDA-231) was implanted in five mice per group. The dynamic contrast effects of the chelates were compared by performing DCE MR imaging with intravenous application of Fe-DTPA or Fe-tCDTA on day 1 and DCE MR imaging in the same tumors with gadopentetate dimeglumine on day 2. Quantitative DCE maps were generated with software and were compared by means of a one-tailed Pearson correlation test. Results Relaxivities in serum (0.94 T at room temperature) of Fe-tCDTA (r1 = 2.2 mmol -1 · sec -1 , r2 = 2.5 mmol -1 · sec -1 ) and Fe-DTPA (r1 = 0.9 mmol -1 · sec -1 , r2 = 0.9 mmol -1 · sec -1 ) were approximately twofold and fivefold lower, respectively, compared with those of gadopentetate dimeglumine (r1 = 4.1 mmol -1 · sec -1 , r2 = 4.8 mmol -1 · sec -1 ). Used at moderately higher concentrations, however, iron chelates generated similar contrast effects at T1-weighted MR imaging in vitro in serum, in vivo in blood, and for DCE MR imaging of breast cancer xenografts. The volume transfer constant values for Fe-DTPA and Fe-tCDTA in the same tumors correlated well with those observed for gadopentetate dimeglumine (Fe-tCDTA Pearson R, 0.99; P = .0003; Fe-DTPA Pearson R, 0.97; P

  1. Uterine cervical carcinoma: a comparison of two- and three-dimensional T2-weighted turbo spin-echo MR imaging at 3.0 T for image quality and local-regional staging

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Y.R. [The Catholic University of Korea, Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, 222, Banpo-daero, Seocho-gu, Seoul (Korea, Republic of); The Catholic University of Korea, Department of Radiology, Incheon St. Mary' s Hospital, College of Medicine, Bupyeong 6-dong, Bupyeong-gu, Incheon (Korea, Republic of); Rha, S.E.; Choi, B.G.; Oh, S.N.; Park, M.Y.; Byun, J.Y. [The Catholic University of Korea, Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, 222, Banpo-daero, Seocho-gu, Seoul (Korea, Republic of)

    2013-04-15

    To compare three-dimensional (3D) T2-weighted turbo spin-echo (TSE) with multiplanar two-dimensional (2D) T2-weighted TSE for the evaluation of invasive cervical carcinoma. Seventy-five patients with cervical carcinoma underwent MRI of the pelvis at 3.0 T, using both 5-mm-thick multiplanar 2D (total acquisition time = 12 min 25 s) and 1-mm-thick coronal 3D T2-weighted TSE sequences (7 min 20 s). Quantitative analysis of signal-to-noise ratio (SNR) and qualitative analysis of image quality were performed. Local-regional staging was performed in 45 patients who underwent radical hysterectomy. The estimated SNR of cervical carcinoma and the relative tumour contrast were significantly higher on 3D imaging (P < 0.0001). Tumour conspicuity was better with the 3D sequence, but the sharpness of tumour margin was better with the 2D sequence. No significant difference in overall image quality was noted between the two sequences (P = 0.38). There were no significant differences in terms of the diagnostic accuracy, sensitivity, and specificity of parametrial invasion, vaginal invasion, and lymph node metastases. Multiplanar reconstruction 3D T2-weighted imaging is largely equivalent to 2D T2-weighted imaging for overall image quality and staging accuracy of cervical carcinoma with a shorter MR data acquisition, but has limitations with regard to the sharpness of the tumour margin. circle 3D T2-weighted MR sequence is equivalent to 2D for cervical carcinoma staging. (orig.)

  2. Efficacy of gadoxetic acid-enhanced magnetic resonance cholangiography compared with T2-weighted magnetic resonance cholangiography in patients with liver cirrhosis

    Directory of Open Access Journals (Sweden)

    Wen-Pei Wu

    2015-12-01

    Conclusion: CE-MRC is not superior to conventional T2W-MRC with respect to biliary visualization in patients with liver cirrhosis. However, a combination of T2W-MRC and CE-MRC provides significantly better visualization of biliary structures than T2W-MRC alone.

  3. T1ρ-weighted Dynamic Glucose-enhanced MR Imaging in the Human Brain.

    Science.gov (United States)

    Paech, Daniel; Schuenke, Patrick; Koehler, Christina; Windschuh, Johannes; Mundiyanapurath, Sibu; Bickelhaupt, Sebastian; Bonekamp, David; Bäumer, Philipp; Bachert, Peter; Ladd, Mark E; Bendszus, Martin; Wick, Wolfgang; Unterberg, Andreas; Schlemmer, Heinz-Peter; Zaiss, Moritz; Radbruch, Alexander

    2017-12-01

    Purpose To evaluate the ability to detect intracerebral regions of increased glucose concentration at T1ρ-weighted dynamic glucose-enhanced (DGE) magnetic resonance (MR) imaging at 7.0 T. Materials and Methods This prospective study was approved by the institutional review board. Nine patients with newly diagnosed glioblastoma and four healthy volunteers were included in this study from October 2015 to July 2016. Adiabatically prepared chemical exchange-sensitive spin-lock imaging was performed with a 7.0-T whole-body unit with a temporal resolution of approximately 7 seconds, yielding the time-resolved DGE contrast. T1ρ-weighted DGE MR imaging was performed with injection of 100 mL of 20% d-glucose via the cubital vein. Glucose enhancement, given by the relative signal intensity change at T1ρ-weighted MR imaging (DGEρ), was quantitatively investigated in brain gray matter versus white matter of healthy volunteers and in tumor tissue versus normal-appearing white matter of patients with glioblastoma. The median signal intensities of the assessed brain regions were compared by using the Wilcoxon rank-sum test. Results In healthy volunteers, the median signal intensity in basal ganglia gray matter (DGEρ = 4.59%) was significantly increased compared with that in white matter tissue (DGEρ = 0.65%) (P = .028). In patients, the median signal intensity in the glucose-enhanced tumor region as displayed on T1ρ-weighted DGE images (DGEρ = 2.02%) was significantly higher than that in contralateral normal-appearing white matter (DGEρ = 0.08%) (P brain glucose physiology and pathophysiologically increased glucose uptake and may have the potential to provide information about glucose metabolism in tumor tissue. © RSNA, 2017 Online supplemental material is available for this article.

  4. Multicontrast-weighted magnetic resonance imaging of atherosclerotic plaques at 3.0 and 1.5 Tesla: ex-vivo comparison with histopathologic correlation

    International Nuclear Information System (INIS)

    Koops, Andreas; Ittrich, Harald; Priest, Andrew; Stork, Alexander; Adam, Gerhard; Weber, Christoph; Petri, Susan; Lockemann, Ute

    2007-01-01

    The purpose was to analyze magnetic resonance (MR) plaque imaging at 3.0 Tesla and 1.5 Tesla in correlation with histopathology. MR imaging (MRI) of the abdominal aorta and femoral artery was performed on seven corpses using T1-weighted, T2-weighted, and PD-weighted sequences at 3.0 and 1.5 Tesla. Cross-sectional images at the branching of the inferior mesenteric artery and the profunda femoris were rated with respect to image quality. Corresponding cross sections of the imaged vessels were obtained at autopsy. The atherosclerotic plaques in the histological slides and MR images were classified according to the American Heart Association (AHA) and analyzed for differences. MRI at 3.0 Tesla offered superior depiction of arterial wall composition in all contrast weightings, rated best for T2-weighted images. Comparing for field strength, the highest differences were observed in T1-weighted and T2-weighted techniques (both P≤0.001), with still significant differences in PD-weighted sequence (P≤0.005). The majority of plaques were histologically classified as calcified plaques. In up to 21% of the cases, MRI at both field strengths detected signal loss characteristic of calcification although calcified plaque was absent in histology. MRI at 3.0 Tesla offers superior plaque imaging quality compared with 1.5 Tesla, but further work is necessary to determine whether this translates in superior diagnostic accuracy. (orig.)

  5. Utility of dual echo T2-weighted turbo spin echo MR imaging for differentiation of solid, malignant hepatic lesions from nonsolid, benign hepatic lesions

    International Nuclear Information System (INIS)

    Yang, Dal Mo; Yoon, Myung Hwan; Kim, Hak Soo; Lee, Eun Joo; Kim, Jong Ho; Kim, Hyung Sik; Chung, Jin Woo

    1999-01-01

    To evaluate the additive value of multiphasic contrast-enhanced dynamic MR imaging as a supplement to dual-echo T2-weighted TSE MR imaging for the differentiation of solid, malignant hepatic lesions from nonsolid, benign hepatic lesions. Two radiologists retrospectively reviewed dual-echo T2-weighted TSE MR images and gadolinium-enhanced MR images in 51 patients with hepatic lesions (28 malignant, 69 benign). For the differentiation of malignant from benign lesions, as seen on dual-echo T2-weighted TSE MR images, we evaluated sensitivity, specificity, and accuracy, and compared with the results with those for dual echo T2-weighted MR images plus multiphasic contrast-enhanced dynamic MR images. In addition, Az values for dual echo T2-weighted MR images were compared with those for dual echo T2-weighted MR images plus multiphasic contrast-enhanced dynamic MR images. For the differentiation of malignant from benign hepatic lesions, as seen on dual-echo T2-weighted TSE images, sensitivity, specificity, and accuracy were 80.0%, 97.5%, and 93.9%, respectively, for lesions less than 3cm in diameter, and 92.3%, 95.0%, and 93.5%, respectively, for those that were 3cm or larger. The results for dual-echo T2-weighted MR imaging plus multiphasic contrast-enhanced dynamic MR imaging were 86.7%, 100.0%, and 97.3%, respectively, for lesions less than 3cm, and 92.3%, 100.0%, and 95.7%, respectively for those that were 3cm or larger. There were no significant differences in sensitivity, specificity, or accuracy between the results obtained using dual-echo T2-weighted MR imaging and those obtained with dual-echo T2-weighted MR imaging plus multiphasic contrast-enhanced dynamic MR imaging. Nor were these statistically significant differences in Az values between the two groups. For the differentiation of solid, malignant hepatic lesions from nonsolid, benign hepatic lesions, there is no difference in accuracy between dual-echo T2-weighted TSE MR imaging and the additional use of

  6. 3 T MRI of hepatocellular carcinomas in patients with cirrhosis: Does T2-weighted imaging provide added value?

    International Nuclear Information System (INIS)

    Guo, L.; Liang, C.; Yu, T.; Wang, G.; Li, N.; Sun, H.; Gao, F.; Liu, C.

    2012-01-01

    Aim: To assess whether T2-weighted imaging (T2WI) provides any added value for the detection of hepatocellular carcinoma (HCC) in patients with cirrhosis, especially for lesions smaller than 2 cm. Materials and methods: Sixty-five patients with cirrhosis underwent liver 3 T MRI. Images were qualitatively analysed independently by two observers in two separate sessions, including a dynamic enhanced session and a combination of dynamic and T2WI. The diagnostic accuracy was evaluated using the alternating free-response receiver operating characteristic. Sensitivity and positive predictive values were calculated for all HCCs and for the subgroup of HCCs that were smaller than 2 cm. Additionally, artefacts on T2WI were evaluated by two observers in consensus. Results: Ninety HCCs (>2 cm n = 36; ≤2 cm n = 54) were detected in 46 patients. For all HCCs and for lesions smaller than 2 cm, the sensitivities were significantly higher for the combined session than the dynamic session alone (p < 0.05). Conversely, for the Az and positive predictive values, there was no significant difference between the two sessions. For smaller HCC, 9% (5/54) and 7% (4/54) of the 54 HCCs were correctly interpreted by observers 1 and 2, respectively, only when T2WI was included. Three false-positive lesions (≤2 cm) were correctly diagnosed by one of the observers after combining T2WI. Conspicuity of only one large HCC was severely reduced by the artefacts from massive ascites. Conclusion: At 3 T liver imaging, combining with T2WI can improve the sensitivity of detection of HCC compared with dynamic MRI alone by increasing observer confidence, especially for lesions smaller than 2 cm. Additionally, T2 image quality was not significantly affected by artefacts.

  7. 3 T MRI of hepatocellular carcinomas in patients with cirrhosis: Does T2-weighted imaging provide added value?

    Energy Technology Data Exchange (ETDEWEB)

    Guo, L.; Liang, C.; Yu, T.; Wang, G.; Li, N.; Sun, H.; Gao, F. [Shandong Medical Imaging Research Institute, Shandong University, Jinan (China); Liu, C., E-mail: liucheng1025@163.com [Shandong Medical Imaging Research Institute, Shandong University, Jinan (China)

    2012-04-15

    Aim: To assess whether T2-weighted imaging (T2WI) provides any added value for the detection of hepatocellular carcinoma (HCC) in patients with cirrhosis, especially for lesions smaller than 2 cm. Materials and methods: Sixty-five patients with cirrhosis underwent liver 3 T MRI. Images were qualitatively analysed independently by two observers in two separate sessions, including a dynamic enhanced session and a combination of dynamic and T2WI. The diagnostic accuracy was evaluated using the alternating free-response receiver operating characteristic. Sensitivity and positive predictive values were calculated for all HCCs and for the subgroup of HCCs that were smaller than 2 cm. Additionally, artefacts on T2WI were evaluated by two observers in consensus. Results: Ninety HCCs (>2 cm n = 36; {<=}2 cm n = 54) were detected in 46 patients. For all HCCs and for lesions smaller than 2 cm, the sensitivities were significantly higher for the combined session than the dynamic session alone (p < 0.05). Conversely, for the Az and positive predictive values, there was no significant difference between the two sessions. For smaller HCC, 9% (5/54) and 7% (4/54) of the 54 HCCs were correctly interpreted by observers 1 and 2, respectively, only when T2WI was included. Three false-positive lesions ({<=}2 cm) were correctly diagnosed by one of the observers after combining T2WI. Conspicuity of only one large HCC was severely reduced by the artefacts from massive ascites. Conclusion: At 3 T liver imaging, combining with T2WI can improve the sensitivity of detection of HCC compared with dynamic MRI alone by increasing observer confidence, especially for lesions smaller than 2 cm. Additionally, T2 image quality was not significantly affected by artefacts.

  8. Diffusion-Weighted Magnetic Resonance Imaging in Monitoring Rectal Cancer Response to Neoadjuvant Chemoradiotherapy

    International Nuclear Information System (INIS)

    Barbaro, Brunella; Vitale, Renata; Valentini, Vincenzo; Illuminati, Sonia; Vecchio, Fabio M.; Rizzo, Gianluca; Gambacorta, Maria Antonietta; Coco, Claudio; Crucitti, Antonio; Persiani, Roberto; Sofo, Luigi; Bonomo, Lorenzo

    2012-01-01

    Purpose: To prospectively monitor the response in patients with locally advanced nonmucinous rectal cancer after chemoradiotherapy (CRT) using diffusion-weighted magnetic resonance imaging. The histopathologic finding was the reference standard. Methods and Materials: The institutional review board approved the present study. A total of 62 patients (43 men and 19 women; mean age, 64 years; range, 28–83) provided informed consent. T 2 - and diffusion-weighted magnetic resonance imaging scans (b value, 0 and 1,000 mm 2 /s) were acquired before, during (mean 12 days), and 6–8 weeks after CRT. We compared the median apparent diffusion coefficients (ADCs) between responders and nonresponders and examined the associations with the Mandard tumor regression grade (TRG). The postoperative nodal status (ypN) was evaluated. The Mann-Whitney/Wilcoxon two-sample test was used to evaluate the relationships among the pretherapy ADCs, extramural vascular invasion, early percentage of increases in ADCs, and preoperative ADCs. Results: Low pretreatment ADCs ( −3 mm 2 /s) were correlated with TRG 4 scores (p = .0011) and associated to extramural vascular invasion with ypN+ (85.7% positive predictive value for ypN+). During treatment, the mean percentage of increase in tumor ADC was significantly greater in the responders than in the nonresponders (p 23% ADC increase had a 96.3% negative predictive value for TRG 4. In 9 of 16 complete responders, CRT-related tumor downsizing prevented ADC evaluations. The preoperative ADCs were significantly different (p = .0012) between the patients with and without downstaging (preoperative ADC ≥1.4 × 10 −3 mm 2 /s showed a positive and negative predictive value of 78.9% and 61.8%, respectively, for response assessment). The TRG 1 and TRG 2–4 groups were not significantly different. Conclusion: Diffusion-weighted magnetic resonance imaging seems to be a promising tool for monitoring the response to CRT.

  9. Three-dimensional susceptibility-weighted imaging and two-dimensional T2*-weighted gradient-echo imaging of intratumoral hemorrhages in pediatric diffuse intrinsic pontine glioma

    International Nuclear Information System (INIS)

    Loebel, Ulrike; Sedlacik, Jan; Sabin, Noah D.; Hillenbrand, Claudia M.; Patay, Zoltan; Kocak, Mehmet; Broniscer, Alberto

    2010-01-01

    We compared the sensitivity and specificity of T2*-weighted gradient-echo imaging (T2*-GRE) and susceptibility-weighted imaging (SWI) in determining prevalence and cumulative incidence of intratumoral hemorrhages in children with diffuse intrinsic pontine glioma (DIPG) undergoing antiangiogenic and radiation therapy. Patients were recruited from an institutional review board-approved prospective phase I trial of vandetanib administered in combination with radiation therapy. Patient consent was obtained before enrollment. Consecutive T2*-GRE and SWI exams of 17 patients (F/M: 9/8; age 3-17 years) were evaluated. Two reviewers (R1 and R2) determined the number and size of hemorrhages at baseline and multiple follow-ups (92 scans, mean 5.4/patient). Statistical analyses were performed using descriptive statistics, graphical tools, and mixed-effects Poisson regression models. Prevalence of hemorrhages at diagnosis was 41% and 47%; the cumulative incidences of hemorrhages at 6 months by T2*-GRE and SWI were 82% and 88%, respectively. Hemorrhages were mostly petechial; 9.7% of lesions on T2*-GRE and 5.2% on SWI were hematomas (>5 mm). SWI identified significantly more hemorrhages than T2*-GRE did. Lesions were missed or misinterpreted in 36/39 (R1/R2) scans by T2*-GRE and 9/3 scans (R1/R2) by SWI. Hemorrhages had no clinically significant neurological correlates in patients. SWI is more sensitive than T2*-GRE in detecting hemorrhages and differentiating them from calcification, necrosis, and artifacts. Also, petechial hemorrhages are more common in DIPG at diagnosis than previously believed and their number increases during the course of treatment; hematomas are rare. (orig.)

  10. Everyman's prostate phantom: kiwi-fruit substitute for human prostates at magnetic resonance imaging, diffusion-weighted imaging and magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mueller-Lisse, Ullrich G.; Murer, Sophie; Kuhn, Marissa [University of Munich (' ' Ludwig-Maximilians-Universitaet' ' , LMU), Department of Radiology, Faculty of Medicine, Muenchen (Germany); Mueller-Lisse, Ulrike L. [University of Munich (' ' Ludwig-Maximilians-Universitaet' ' , LMU), Department of Urology, Faculty of Medicine, Muenchen (Germany); Interdisciplinary Oncology Centre Munich (IOZ), Department of Urology, Munich (Germany); Scheidler, Juergen [University of Munich (' ' Ludwig-Maximilians-Universitaet' ' , LMU), Department of Radiology, Faculty of Medicine, Muenchen (Germany); Radiology Centre Munich (RZM), Muenchen (Germany); Scherr, Michael [University of Munich (' ' Ludwig-Maximilians-Universitaet' ' , LMU), Department of Radiology, Faculty of Medicine, Muenchen (Germany); BG Unfallklinik Murnau, Department of Radiology, Murnau am Staffelsee (Germany)

    2017-08-15

    To apply an easy-to-assemble phantom substitute for human prostates in T2-weighted magnetic resonance imaging (T2WI), diffusion-weighted imaging (DWI) and 3D magnetic resonance spectroscopy (MRS). Kiwi fruit were fixed with gel hot and cold compress packs on two plastic nursery pots, separated by a plastic plate, and submerged in tap water inside a 1-L open-spout plastic watering can for T2WI (TR/TE 7500/101 ms), DWI (5500/61 ms, ADC b50-800 s/mm{sup 2} map) and MRS (940/145 ms) at 3.0 T, with phased array surface coils. One green kiwi fruit was additionally examined with an endorectal coil. Retrospective comparison with benign peripheral zone (PZ) and transitional zone (TZ) of prostate (n = 5), Gleason 6-7a prostate cancer (n = 8) and Gleason 7b-9 prostate cancer (n = 7) validated the phantom. Mean contrast between central placenta (CP) and outer pericarp (OP, 0.346-0.349) or peripheral placenta (PP, 0.364-0.393) of kiwi fruit was similar to Gleason 7b-9 prostate cancer and PZ (0.308) in T2WI. ADC values of OP and PP (1.27 ± 0.07-1.37 ± 0.08 mm{sup 2}/s x 10{sup -3}) resembled PZ and TZ (1.39 ± 0.17-1.60 ± 0.24 mm{sup 2}/s x 10{sup -3}), while CP (0.91 ± 0.14-0.99 ± 0.10 mm{sup 2}/s x 10{sup -3}) resembled Gleason 7b-9 prostate cancer (1.00 ± 0.25 mm{sup 2}/s x 10{sup -3}). MR spectra showed peaks of citrate and myo-inositol in kiwi fruit, and citrate and ''choline+creatine'' in prostates. The phantom worked with an endorectal coil, too. The kiwi fruit phantom reproducibly showed zones similar to PZ, TZ and cancer in human prostates in T2WI and DWI and two metabolite peaks in MRS and appears suitable to compare different MR protocols, coil systems and scanners. (orig.)

  11. Fast spin-echo T2-weighted MR imaging of tongue cancer; the value of fat-suppression

    International Nuclear Information System (INIS)

    Kim, Zu Byoung; Na, Dong Gyu; Ryoo, Jae Wook; Kim, Kyeong Ah; Byun, Hong Sik; Baek, Chung Whan; Son, Yong Ik

    2000-01-01

    To compare the diagnostic efficacy of fast spin-echo (FSE) T2-weighted MR imaging with and without fat suppression. Twelve patients (7 men and 5 women; mean age, 48 years) with pathologically proven cancer of the tongue were included in this study. In all of these, FSE T2-weighted MR images with and without fat suppression were obtained in the same imaging planes before surgery or biopsy. Two radiologists visually compared the images thus obtained in terms of detection, extent, and conspicuity of the tumor, and the contrast-to-noise ratio (CNR) of each tumor was also calculated. In all patients, both imaging modalities were equal in terms of tumor detection. In 4 of 12(33%), the extent of the tumor was greater with fat suppression, while in eight (67%), it was almost the same both with and without. In ten patients (83%), the tumor was more conspicuous with fat suppression, and percentage CNRs were significantly higher with fat suppression than without (180±70% and 113±61%, respectively; p=0.02). For the evaluation of patients with tongue cancer, fat-suppressed FSE T2-weighted MR imaging is superior to its conventional equivalent

  12. Usefulness of IDEAL T2-weighted FSE and SPGR imaging in reducing metallic artifacts in the postoperative ankles with metallic hardware

    International Nuclear Information System (INIS)

    Lee, Jung Bin; Cha, Jang Gyu; Lee, Min Hee; Lee, Eun Hye; Lee, Young Koo; Jeon, Chan Hong

    2013-01-01

    The aim of this work is to prospectively compare the effectiveness of iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL), T2-weighted fast spin-echo (FSE), and spoiled gradient-echo (SPGR) MR imaging to frequency selective fat suppression (FSFS) protocols for minimizing metallic artifacts in postoperative ankles with metallic hardware. The T2-weighted and SPGR imaging with IDEAL and FSFS were performed on 21 ankles of 21 patients with metallic hardware. Two musculoskeletal radiologists independently analyzed techniques for visualization of ankle ligaments and articular cartilage, uniformity of fat saturation, and relative size of the metallic artifacts. A paired t test was used for statistical comparisons of MR images between IDEAL and FSFS groups. IDEAL T2-weighted FSE and SPGR images enabled significantly improved visualization of articular cartilage (p < 0.05), the size of metallic artifact (p < 0.05), and the uniformity of fat saturation (p < 0.05). However, no significant improvement was found in the visibility of ligaments. IDEAL T2-weighted FSE and SPGR imaging effectively reduces the degree of tissue-obscuring artifacts produced by fixation hardware in ankle joints and improves image quality compared to FSFS T2-weighted FSE and SPGR imaging. However, visibility of ligaments was not improved using IDEAL imaging. (orig.)

  13. Diffusion-weighted magnetic resonance imaging for the initial characterization of non-fatty soft tissue tumors: correlation between T2 signal intensity and ADC values

    Energy Technology Data Exchange (ETDEWEB)

    Gondim Teixeira, Pedro Augusto [Service d' Imagerie Guilloz, CHU Nancy, Nancy (France); Universite de Lorraine, IADI, UMR S 947, Vandoeuvre-les-Nancy (France); Gay, Frederique; Blum, Alain [Service d' Imagerie Guilloz, CHU Nancy, Nancy (France); Chen, Bailiang; Felblinger, Jacques [Universite de Lorraine, IADI, UMR S 947, Vandoeuvre-les-Nancy (France); Zins, Marie [University Versailles St-Quentin, Versailles (France); Inserm, Centre for research in Epidemiology and Population Health (CESP), U1018, Villejuif (France); Sirveaux, Francois [Centre Chirurgical Emile Galle, Service de Chirurgie Traumatologique et Orthopedique, Nancy (France)

    2016-02-15

    To evaluate the performance of quantitative diffusion-weighted imaging (DWI) correlated with T2 signal in differentiating non-fatty benign from malignant tumors. A total of 76 patients with a histologically confirmed non-fatty soft tissue tumors (46 benign and 30 malignant) were prospectively included in this ethics committee approved study. All patients signed an informed consent and underwent MRI with DWI with two b values (0 and 600). ADC values from the solid components of these tumors were obtained and were correlated with the lesion's signal intensity on T2-weighted fat-saturated sequences. ADC values were obtained from adjacent normal muscle to allow calculation of tumor/muscle ADC ratios. There were 58 hyperintense and 18 iso or hypointense lesions. All hypointense lesions were benign. The mean ADC values for benign and malignant tumors were 1.47 ± 0.54 x 10{sup -3} and 1.17 ± 0.38 x 10{sup -3} mm{sup 2}/s respectively (p < 0.005). The mean ADC ratio in benign iso or hypointense tumors was significantly lower than that of hyperintense ones (0.76 ± 0.21 versus 1.58 ± 0.82 - p < 0.0001). An ADC ratio lower than 0.915 was highly specific for malignancy (96.4 %), whereas an ADC ratio higher than 1.32 was highly sensitive for benign lesions (90 %). ADC analysis can be useful in the initial characterization of T2 hyperintense non-fatty soft tissue masses, although this technique alone is not likely to change patient management. (orig.)

  14. Artifact free T2{sup *}-weighted imaging at high spatial resolution using segmented EPI sequences

    Energy Technology Data Exchange (ETDEWEB)

    Heiler, Patrick Michael; Schad, Lothar Rudi [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Schmitter, Sebastian [German Cancer Research Center, Heidelberg (Germany). Dept. of Medical Physics in Radiology

    2010-07-01

    The aim of this work was the development of novel measurement techniques that acquire high resolution T2{sup *}-weighted datasets in measurement times as short as possible without suffering from noticeable blurring and ghosting artifacts. Therefore, two new measurement techniques were developed that acquire a smoother k-space than generic multi shot echo planar imaging sequences. One is based on the principle of echo train shifting, the other on the reversed gradient method. Simulations and phantom measurements demonstrate that echo train shifting works properly and reduces artifacts in multi shot echo planar imaging. For maximum SNR-efficiency this technique was further improved by adding a second contrast. Both contrasts can be acquired within a prolongation in measurement time by a factor of 1.5, leading to an SNR increase by approximately {radical}2. Furthermore it is demonstrated that the reversed gradient method remarkably reduces artifacts caused by a discontinuous k-space weighting. Assuming sequence parameters as feasible for fMRI experiments, artifact free T2{sup *}-weighted images with a matrix size of 256 x 256 leading to an in-plane resolution in the submillimeter range can be obtained in about 2 s per slice. (orig.)

  15. Magnetic moment and magnetocrystalline anisotropy of 3d-ion subsystem in R2T14B

    International Nuclear Information System (INIS)

    Bartashevich, M.I.; Kudrevatykh, N.V.; Andreev, A.V.; Rejmer, V.A.

    1990-01-01

    The effect of substituting cobalt for iron on the magnetic moment, magneto-crystalline anisotropy and thermal expansion of R 2 (Fe 1-x Co x ) 14 B single crystals (R=Y, Gd, 0≤x≤0.3) is investigated. The uniaxial magnetic anisotropy constant K 1 for the 3d-subsystem passes through a maximum at T=4.2 K with increasing Co concentration. For T c the temperature dependence of K 1 does not possess a positive slope. The magnetic moment of the 3d-subsystem at 4.2 K does not exhibit the maximum at intermediate concentrations observed for most R(Fe, Co)-intermetallics. An explanation is presented of the changes in the magnetic properties. It is shown that the variation of the interatomic distances on thermal expansion should not affect the magnitude of the anisotropy constant of the 3d- and R-subsystems

  16. MR Imaging of the Spine at 3.0T with T2-Weighted IDEAL Fast Recovery Fast Spin-Echo Technique

    International Nuclear Information System (INIS)

    Ren, Ai Jun; Guo, Yong; Tian, Shu Ping; Shi, Li Jing; Huang, Min Hua

    2012-01-01

    To compare the iterative decomposition of water and fat with echo asymmetry and the least-squares estimation (IDEAL) method with a fat-saturated T2-weighted (T2W) fast recovery fast spin-echo (FRFSE) imaging of the spine. Images acquired at 3.0 Tesla (T) in 35 patients with different spine lesions using fat-saturated T2W FRFSE imaging were compared with T2W IDEAL FRFSE images. Signal-to-noise ratio (SNR)-efficiencies measurements were made in the vertebral bodies and spinal cord in the mid-sagittal plane or nearest to the mid-sagittal plane. Images were scored with the consensus of two experienced radiologists on a four-point grading scale for fat suppression and overall image quality. Statistical analysis of SNR-efficiency, fat suppression and image quality scores was performed with a paired Student's t test and Wilcoxon's signed rank test. Signal-to-noise ratio-efficiency for both vertebral body and spinal cord was higher with T2W IDEAL FRFSE imaging (p < 0.05) than with T2W FRFSE imaging. T2W IDEAL FRFSE demonstrated superior fat suppression (p < 0.01) and image quality (p < 0.01) compared to fat-saturated T2W FRFSE. As compared with fat-saturated T2W FRFSE, IDEAL can provide a higher image quality, higher SNR-efficiency, and consistent, robust and uniform fat suppression. T2W IDEAL FRFSE is a promising technique for MR imaging of the spine at 3.0T.

  17. Structural and magnetic properties of UCo1/3T2/3Al solid solutions (T = Ru, Pt, Rh)

    International Nuclear Information System (INIS)

    Andreev, A. V.; Bordallo, H. N.; Chang, S.; Nakotte, H.; Schultz, A. J.; Sechovsky, V.; Torikachvili, M. S.

    1999-01-01

    We report on neutron diffraction studies of UCo 1/3 T 2/3 Al (T = Ru, Pt, Rh). All three solid solutions form in the hexagonal ZrNiAl structure. The Ru-containing compound is found to be chemically ordered, while the Pt-containing compound is nearly disordered and the Rh-containing compound is purely disordered. All three compounds exhibit long-range magnetic order with rather small U moments

  18. Performance of PROPELLER relative to standard FSE T2-weighted imaging in pediatric brain MRI

    Energy Technology Data Exchange (ETDEWEB)

    Vertinsky, A.T. [Vancouver General Hospital, Department of Radiology, Vancouver (Canada); University of British Columbia, Department of Radiology, Vancouver (Canada); Rubesova, Erika; Bammer, Sabine; White, Allan; Barnes, Patrick D. [Stanford University Medical Center, Lucile Salter Packard Children' s Hospital, Palo Alto, CA (United States); Krasnokutsky, Michael V. [Madigan Army Medical Center, Department of Radiology, Tacoma, WA (United States); Uniformed Services University of Health Sciences, Department of Radiology, Bethesda, MD (United States); Rosenberg, Jarrett; Bammer, Roland [Lucas Center, Stanford University, Department of Radiology, Palo Alto, CA (United States)

    2009-10-15

    T2-weighted fast spin-echo imaging (T2-W FSE) is frequently degraded by motion in pediatric patients. MR imaging with periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) employs alternate sampling of k-space to achieve motion reduction. To compare T2-W PROPELLER FSE (T2-W PROP) with conventional T2-W FSE for: (1) image quality; (2) presence of artefacts; and (3) ability to detect lesions. Ninety-five pediatric patients undergoing brain MRI (1.5 T) were evaluated with T2-W FSE and T2-W PROP. Three independent radiologists rated T2-W FSE and T2-W PROP, assessing image quality, presence of artefacts, and diagnostic confidence. Chi-square analysis and Wilcoxon signed rank test were used to assess the radiologists' responses. Compared with T2-W FSE, T2-W PROP demonstrated better image quality and reduced motion artefacts, with the greatest benefit in children younger than 6 months. Although detection rates were comparable for the two sequences, blood products were more conspicuous on T2-W FSE. Diagnostic confidence was higher using T2-W PROP in children younger than 6 months. Average inter-rater agreement was 87%. T2-W PROP showed reduced motion artefacts and improved diagnostic confidence in children younger than 6 months. Thus, use of T2-W PROP rather than T2-W FSE should be considered in routine imaging of this age group, with caution required in identifying blood products. (orig.)

  19. Performance of PROPELLER relative to standard FSE T2-weighted imaging in pediatric brain MRI

    International Nuclear Information System (INIS)

    Vertinsky, A.T.; Rubesova, Erika; Bammer, Sabine; White, Allan; Barnes, Patrick D.; Krasnokutsky, Michael V.; Rosenberg, Jarrett; Bammer, Roland

    2009-01-01

    T2-weighted fast spin-echo imaging (T2-W FSE) is frequently degraded by motion in pediatric patients. MR imaging with periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) employs alternate sampling of k-space to achieve motion reduction. To compare T2-W PROPELLER FSE (T2-W PROP) with conventional T2-W FSE for: (1) image quality; (2) presence of artefacts; and (3) ability to detect lesions. Ninety-five pediatric patients undergoing brain MRI (1.5 T) were evaluated with T2-W FSE and T2-W PROP. Three independent radiologists rated T2-W FSE and T2-W PROP, assessing image quality, presence of artefacts, and diagnostic confidence. Chi-square analysis and Wilcoxon signed rank test were used to assess the radiologists' responses. Compared with T2-W FSE, T2-W PROP demonstrated better image quality and reduced motion artefacts, with the greatest benefit in children younger than 6 months. Although detection rates were comparable for the two sequences, blood products were more conspicuous on T2-W FSE. Diagnostic confidence was higher using T2-W PROP in children younger than 6 months. Average inter-rater agreement was 87%. T2-W PROP showed reduced motion artefacts and improved diagnostic confidence in children younger than 6 months. Thus, use of T2-W PROP rather than T2-W FSE should be considered in routine imaging of this age group, with caution required in identifying blood products. (orig.)

  20. Magnetic phase diagram of UNi2Si2 under magnetic field and high-pressure

    International Nuclear Information System (INIS)

    Honda, F.; Oomi, G.; Svoboda, P.; Syshchenko, A.; Sechovsky, V.; Khmelevski, S.; Divis, M.; Andreev, A.V.; Takeshita, N.; Mori, N.; Menovsky, A.A.

    2001-01-01

    Measurements of electrical resistance under high pressure and neutron diffraction in high-magnetic field of single crystalline UNi 2 Si 2 have been performed. We have found the analogy between the p-T and B-T magnetic phase diagrams. It is also found that the propagation vector q Z of incommensurate antiferromagnetic phase decreases with increasing magnetic field. A new pronounced pressure-induced incommensurate-commensurate magnetic phase transition has been detected

  1. Experimentally stabilized superconducting magnet with inner diameter of 700 mm

    Energy Technology Data Exchange (ETDEWEB)

    Vetlitskii, I A; Belonogov, A V; Dobrov, V M; Krylov, V L; Lebedev, A V; Lomkatsi, G S; Nilov, A F; Smolyankin, V T

    1974-05-01

    An experimental magnet, SPM-70, with the following characteristics was constructed. The inner diameter of the winding was 730 mm; outer diameter of the winding 1000 mm; height of winding 310 mm; magnetic induction at the center of the magnet 1.45 T; maximum magnetic induction 2.4 T; operation current 820 A; ampere-turns 1.07 x 10/sup 6/; design current density 2560 A/cm/sup 2/; stored energy 500 kJ; superconducting alloy Nb+50% Zr; weight of superconductor 23 kg; weight of copper 210 kg; resistivity of the copper in the strips at T = 4.2 K, B = 2.5 T, 2.6 x 10/sup -8/ ..cap omega.. cm.

  2. MR relaxometry in chronic liver diseases: Comparison of T1 mapping, T2 mapping, and diffusion-weighted imaging for assessing cirrhosis diagnosis and severity

    Energy Technology Data Exchange (ETDEWEB)

    Cassinotto, Christophe, E-mail: christophe.cassinotto@chu-bordeaux.fr [Department of Diagnostic and Interventional Imaging, Hôpital Haut-Lévêque, Centre Hospitalier Universitaire et Université de Bordeaux, 1 Avenue de Magellan, 33604 Pessac (France); INSERM U1053, Université Bordeaux, Bordeaux (France); Feldis, Matthieu, E-mail: matthieu.feldis@chu-bordeaux.fr [Department of Diagnostic and Interventional Imaging, Hôpital Haut-Lévêque, Centre Hospitalier Universitaire et Université de Bordeaux, 1 Avenue de Magellan, 33604 Pessac (France); Vergniol, Julien, E-mail: julien.vergniol@chu-bordeaux.fr [Centre D’investigation de la Fibrose Hépatique, Hôpital Haut-Lévêque, Centre Hospitalier Universitaire de Bordeaux, 1 Avenue de Magellan, 33604 Pessac (France); Mouries, Amaury, E-mail: amaury.mouries@chu-bordeaux.fr [Department of Diagnostic and Interventional Imaging, Hôpital Haut-Lévêque, Centre Hospitalier Universitaire et Université de Bordeaux, 1 Avenue de Magellan, 33604 Pessac (France); Cochet, Hubert, E-mail: hubert.cochet@chu-bordeaux.fr [Department of Diagnostic and Interventional Imaging, Hôpital Haut-Lévêque, Centre Hospitalier Universitaire et Université de Bordeaux, 1 Avenue de Magellan, 33604 Pessac (France); and others

    2015-08-15

    Highlights: • The use of MR to classify cirrhosis in different stages is a new interesting field. • We compared liver and spleen T1 mapping, T2 mapping and diffusion-weighted imaging. • MR relaxometry using liver T1 mapping is accurate for the diagnosis of cirrhosis. • Liver T1 mapping shows that values increase with the severity of cirrhosis. • Diffusion-weighted imaging is less accurate than T1 mapping while T2 mapping is not reliable. - Abstract: Background: MR relaxometry has been extensively studied in the field of cardiac diseases, but its contribution to liver imaging is unclear. We aimed to compare liver and spleen T1 mapping, T2 mapping, and diffusion-weighted MR imaging (DWI) for assessing the diagnosis and severity of cirrhosis. Methods: We prospectively included 129 patients with normal (n = 40) and cirrhotic livers (n = 89) from May to September 2014. Non-enhanced liver T1 mapping, splenic T2 mapping, and liver and splenic DWI were measured and compared for assessing cirrhosis severity using Child-Pugh score, MELD score, and presence or not of large esophageal varices (EVs) and liver stiffness measurements using Fibroscan{sup ®} as reference. Results: Liver T1 mapping was the only variable demonstrating significant differences between normal patients (500 ± 79 ms), Child-Pugh A patients (574 ± 84 ms) and Child-Pugh B/C patients (690 ± 147 ms; all p-values <0.00001). Liver T1 mapping had a significant correlation with Child-Pugh score (Pearson's correlation coefficient of 0.46), MEDL score (0.30), and liver stiffness measurement (0.52). Areas under the receiver operating characteristic curves of liver T1 mapping for the diagnosis of cirrhosis (O.85; 95% confidence intervals (CI), 0.77–0.91), Child-Pugh B/C cirrhosis (0.87; 95%CI, 0.76–0.93), and large EVs (0.75; 95%CI, 0.63–0.83) were greater than that of spleen T2 mapping, liver and spleen DWI (all p-values < 0.01). Conclusion: Liver T1 mapping is a promising new diagnostic

  3. MR relaxometry in chronic liver diseases: Comparison of T1 mapping, T2 mapping, and diffusion-weighted imaging for assessing cirrhosis diagnosis and severity

    International Nuclear Information System (INIS)

    Cassinotto, Christophe; Feldis, Matthieu; Vergniol, Julien; Mouries, Amaury; Cochet, Hubert

    2015-01-01

    Highlights: • The use of MR to classify cirrhosis in different stages is a new interesting field. • We compared liver and spleen T1 mapping, T2 mapping and diffusion-weighted imaging. • MR relaxometry using liver T1 mapping is accurate for the diagnosis of cirrhosis. • Liver T1 mapping shows that values increase with the severity of cirrhosis. • Diffusion-weighted imaging is less accurate than T1 mapping while T2 mapping is not reliable. - Abstract: Background: MR relaxometry has been extensively studied in the field of cardiac diseases, but its contribution to liver imaging is unclear. We aimed to compare liver and spleen T1 mapping, T2 mapping, and diffusion-weighted MR imaging (DWI) for assessing the diagnosis and severity of cirrhosis. Methods: We prospectively included 129 patients with normal (n = 40) and cirrhotic livers (n = 89) from May to September 2014. Non-enhanced liver T1 mapping, splenic T2 mapping, and liver and splenic DWI were measured and compared for assessing cirrhosis severity using Child-Pugh score, MELD score, and presence or not of large esophageal varices (EVs) and liver stiffness measurements using Fibroscan ® as reference. Results: Liver T1 mapping was the only variable demonstrating significant differences between normal patients (500 ± 79 ms), Child-Pugh A patients (574 ± 84 ms) and Child-Pugh B/C patients (690 ± 147 ms; all p-values <0.00001). Liver T1 mapping had a significant correlation with Child-Pugh score (Pearson's correlation coefficient of 0.46), MEDL score (0.30), and liver stiffness measurement (0.52). Areas under the receiver operating characteristic curves of liver T1 mapping for the diagnosis of cirrhosis (O.85; 95% confidence intervals (CI), 0.77–0.91), Child-Pugh B/C cirrhosis (0.87; 95%CI, 0.76–0.93), and large EVs (0.75; 95%CI, 0.63–0.83) were greater than that of spleen T2 mapping, liver and spleen DWI (all p-values < 0.01). Conclusion: Liver T1 mapping is a promising new diagnostic tool for

  4. In vivo T2* weighted MRI visualizes cardiac lesions in murine models of acute and chronic viral myocarditis

    Science.gov (United States)

    Helluy, Xavier; Sauter, Martina; Ye, Yu-Xiang; Lykowsky, Gunthard; Kreutner, Jakob; Yilmaz, Ali; Jahns, Roland; Boivin, Valerie; Kandolf, Reinhard; Jakob, Peter M.; Hiller, Karl-Heinz; Klingel, Karin

    2017-01-01

    Objective Acute and chronic forms of myocarditis are mainly induced by virus infections. As a consequence of myocardial damage and inflammation dilated cardiomyopathy and chronic heart failure may develop. The gold standard for the diagnosis of myocarditis is endomyocardial biopsies which are required to determine the etiopathogenesis of cardiac inflammatory processes. However, new non-invasive MRI techniques hold great potential in visualizing cardiac non-ischemic inflammatory lesions at high spatial resolution, which could improve the investigation of the pathophysiology of viral myocarditis. Results Here we present the discovery of a novel endogenous T2* MRI contrast of myocardial lesions in murine models of acute and chronic CVB3 myocarditis. The evaluation of infected hearts ex vivo and in vivo by 3D T2w and T2*w MRI allowed direct localization of virus-induced myocardial lesions without any MRI tracer or contrast agent. T2*w weighted MRI is able to detect both small cardiac lesions of acute myocarditis and larger necrotic areas at later stages of chronic myocarditis, which was confirmed by spatial correlation of MRI hypointensity in myocardium with myocardial lesions histologically. Additional in vivo and ex vivo MRI analysis proved that the contrast mechanism was due to a strong paramagnetic tissue alteration in the vicinity of myocardial lesions, effectively pointing towards iron deposits as the primary contributor of contrast. The evaluation of the biological origin of the MR contrast by specific histological staining and transmission electron microscopy revealed that impaired iron metabolism primarily in mitochondria caused iron deposits within necrotic myocytes, which induces strong magnetic susceptibility in myocardial lesions and results in strong T2* contrast. Conclusion This T2*w MRI technique provides a fast and sensitive diagnostic tool to determine the patterns and the severity of acute and chronic enteroviral myocarditis and the precise

  5. Correlation between T2 relaxation time and intervertebral disk degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Takashima, Hiroyuki; Takebayashi, Tsuneo; Yoshimoto, Mitsunori; Terashima, Yoshinori; Tsuda, Hajime; Ida, Kazunori; Yamashita, Toshihiko [Sapporo Medical University, Department of Orthopedic Surgery, School of Medicine, Sapporo, Hokkaido (Japan)

    2012-02-15

    Magnetic resonance T2 mapping allows for the quantification of water and proteoglycan content within tissues and can be used to detect early cartilage abnormalities as well as to track the response to therapy. The goal of the present study was to use T2 mapping to quantify intervertebral disk water content according to the Pfirrmann classification. This study involved 60 subjects who underwent lumbar magnetic resonance imaging (a total of 300 lumbar disks). The degree of disk degeneration was assessed in the midsagittal section on T2-weighted images according to the Pfirrmann classification (grades I to V). Receiver operating characteristic (ROC) analysis was performed among grades to determine the cut-off values. In the nucleus pulposus, T2 values tended to decrease with increasing grade, and there was a significant difference in T2 values between each grade from grades I to IV. However, there was no significant difference in T2 values in the anterior or posterior annulus fibrosus. T2 values according to disk degeneration level classification were as follows: grade I (>116.8 ms), grade II (92.7-116.7 ms), grade III (72.1-92.6 ms), grade IV (<72.0 ms). T2 values decreased with increasing Pfirrmann classification grade in the nucleus pulposus, likely reflecting a decrease in proteoglycan and water content. Thus, T2 value-based measurements of intervertebral disk water content may be useful for future clinical research on degenerative disk diseases. (orig.)

  6. D-T axicell magnet system for MFTF-α+T

    International Nuclear Information System (INIS)

    Srivastava, V.C.

    1983-01-01

    The configuration and design of the deuterium-tritium (D-T) axicell superconducting magnets for the Mirror Fusion Test Facility (MFTF-α+T) are described. The MFTF-α+T is an upgrade of the MFTF-B, with new end-plug magnets and a neutron-producing central D-T axicell section. The 4-m long axicell - its length defined by the 12-T peaks in the mirror field - is beam fueled and heated by two beam lines, each with four neutral beam injection ports. Two large superconducting coils (means diameter approx. 3.8 m) located at Z = +-2.40 m, in conjunction with a small copper coil located outside the test volume region, produce the 4.5-T mirror midplane field. This background field is augmented by two copper coils to create the 12-T peak mirror fields at Z = +-2 m. The central region of the axicell accommodates a 1-m-long, replaceable blanket test module. The length (4 m) of the axicell was chosen to provide relatively uniform neutron wall loading over the test module. In many respects, this axicell is less than full scale, but it could be viewed as a short section of a reactor, complete with the support systems and technologies associated with a mirror reactor. The peak field at the superconducting coils is 10.8 T. The coils employ hybrid superconducting winding - Nb 3 Sn conductor in the 8- to 12-T region and NbTi in the 0- to 8-T region. The winding is cryostable and is cooled by a 4.2 K liquid helium bath. The conductor design, the winding design, and the performance analyses for these superconducting coils are described

  7. Histological grade of differentiation of hepatocellular carcinoma: comparison of the efficacy of diffusion-weighted MRI with T2-weighted imaging and angiography-assisted CT

    International Nuclear Information System (INIS)

    Saito, Kazuhiro; Nishio, Ryota; Saguchi, Toru; Akata, Soichi; Tokuuye, Koichi; Moriyasu, Fuminori; Sugimoto, Katsutoshi

    2012-01-01

    The purpose of this study is to determine the usefulness of diffusion-weighted imaging (DWI) for evaluating the histological grade of differentiation of hepatocellular carcinoma (HCC) compared with T2-weighted imaging (T2WI) and tumour haemodynamics. We retrospectively evaluated 32 patients with 42 pathologically confirmed HCC nodules. These patients underwent MRI, CT during arterial portography and CT hepatic arteriography. We evaluated the relationship between the histological grade of differentiation and the apparent diffusion coefficient (ADC) values, conspicuity of tumour on DWI, DWI and T2WI contrast-to-noise (C/N) ratios and tumour haemodynamics. There was no correlation between the histological grade of differentiation and the ADC values. The DWI C/N ratio was significantly different among all histological grades, but the T2WI C/N ratio was not. Tumour conspicuity on DWI correlated well with the histological grade of differentiation, but tumour haemodynamics only partially correlated with the histological grade of differentiation. DWI was useful for evaluating the histological grade of differentiation of HCC.

  8. Evaluation of water content around airway in obstructive sleep apnea patients using peripharyngeal mucosal T2 magnetic resonance imaging.

    Science.gov (United States)

    Rahmawati, Anita; Chishaki, Akiko; Ohkusa, Tomoko; Hashimoto, Sonomi; Adachi, Kazuo; Nagao, Michinobu; Konishi Nishizaka, Mari; Ando, Shin-Ichi

    2017-11-01

    Obstructive sleep apnea (OSA) is common sleep disorder characterized by repetitive episodes of airway closure which usually occurs in the retropalatal region of the oropharynx. It has been known that upper airway mucosa in OSA patients is described as edematous, but not fully clarified. This study aimed to investigate and establish magnetic resonance imaging (MRI) parameter to estimate tissue water content at retropalatal level and its relationship with sleep parameters in OSA patients. Forty-eight subjects with OSA underwent overnight polysomnography and cervical MRI with 1.5-tesla [mean (SD) age 55 (14) years and apnea-hypopnea index (AHI) 45.2 (26.1) events/hour, 79.2% male]. On the axial T2-weighted images from epipharynx to oropharynx, the signal intensities of masseter muscle and peripharyngeal mucosa [T2 mucous-to-masseter intensity ratio (T2MMIR)], was used as water content estimation in the retropalatal region. Partial correlation analysis was performed to examine the correlation between T2MMIR and polysomnography parameters. We found that there were strong and positive correlations between the T2MMIR and AHI (r = 0.545, P < 0.05), supine AHI (r = 0.553, P < 0.05) and REM AHI (r = 0.640, P < 0.01) by partial correlation analysis. Besides, in patients with less efficient sleep who had more stage 1 sleep, significantly higher T2MMIR was noted (r = 0.357, P < 0.05). This study confirmed that peripharyngeal T2MMIR can be a simple parameter representing peripharyngeal tissue water contents related to severe OSA. © 2015 John Wiley & Sons Ltd.

  9. NMR spectroscopy up to 35.2T using a series-connected hybrid magnet.

    Science.gov (United States)

    Gan, Zhehong; Hung, Ivan; Wang, Xiaoling; Paulino, Joana; Wu, Gang; Litvak, Ilya M; Gor'kov, Peter L; Brey, William W; Lendi, Pietro; Schiano, Jeffrey L; Bird, Mark D; Dixon, Iain R; Toth, Jack; Boebinger, Gregory S; Cross, Timothy A

    2017-11-01

    The National High Magnetic Field Laboratory has brought to field a Series-Connected Hybrid magnet for NMR spectroscopy. As a DC powered magnet it can be operated at fields up to 36.1T. The series connection between a superconducting outsert and a resistive insert dramatically minimizes the high frequency fluctuations of the magnetic field typically observed in purely resistive magnets. Current-density-grading among various resistive coils was used for improved field homogeneity. The 48mm magnet bore and 42mm outer diameter of the probes leaves limited space for conventional shims and consequently a combination of resistive and ferromagnetic shims are used. Field maps corrected for field instabilities were obtained and shimming achieved better than 1ppm homogeneity over a cylindrical volume of 1cm diameter and height. The magnetic field is regulated within 0.2ppm using an external 7 Li lock sample doped with paramagnetic MnCl 2 . The improved field homogeneity and field regulation using a modified AVANCE NEO console enables NMR spectroscopy at 1 H frequencies of 1.0, 1.2 and 1.5GHz. NMR at 1.5GHz reflects a 50% increase in field strength above the highest superconducting magnets currently available. Three NMR probes have been constructed each equipped with an external lock rf coil for field regulation. Initial NMR results obtained from the SCH magnet using these probes illustrate the very exciting potential of ultra-high magnetic fields. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Role of MR imaging in the differentiation of benign and nonbenign intracranial meningiomas. The utility of contrast-enhanced T1-weighted images

    International Nuclear Information System (INIS)

    Tanaka, Yasunori; Matsuo, Michimasa

    1996-01-01

    The purpose of this study was to develop useful criteria for distinguishing nonbenign (atypical and malignant) primary intracranial meningiomas from their benign counterparts by using magnetic resonance imaging (MRI). To determine useful MRI findings for this purpose, 12 benign and five nonbenign meningiomas were retrospectively evaluated according to the following items: tumor signal intensity on plain T1-, T2- and proton density-weighted images, degree of perifocal edema on T2-weighted images, morphology of the tumor margin on contrast-enhanced T1-weighted images, presence of irregular nodule and/or mushrooming pattern on contrast-enhanced T1-weighted images, homogeneity of the tumor on contrast-enhanced T1-weighted images, and presence of marked skull destruction. Markedly irregular tumor margin, presence of irregular nodule and/or mushrooming pattern and markedly inhomogeneous enhancing pattern were significantly more frequent in nonbenign meningiomas. We defined these three MRI findings as nonbenign findings, and tried to categorize meningiomas by the number of nonbenign findings. It was found that 10 meningiomas with no or one nonbenign finding were benign lesions, of four meningiomas with two nonbenign findings two were benign lesions and two were nonbenign lesions, and three meningiomas with three nonbenign findings were nonbenign lesions. The two benign meningiomas with two nonbenign findings were accompanied by increased mitotic activity or brain invasion. Contrast-enhanced T1-weighted images were considered very useful in distinguishing benign and nonbenign meningiomas. (author)

  11. Magnetic Resonance Imaging for Patellofemoral Chondromalacia: Is There a Role for T2 Mapping?

    OpenAIRE

    van Eck, Carola F.; Kingston, R. Scott; Crues, John V.; Kharrazi, F. Daniel

    2017-01-01

    Background: Patellofemoral pain is common, and treatment is guided by the presence and grade of chondromalacia. Purpose: To evaluate and compare the sensitivity and specificity in detecting and grading chondral abnormalities of the patella between proton density fat suppression (PDFS) and T2 mapping magnetic resonance imaging (MRI). Study Design: Cohort study; Level of evidence, 2. Methods: A total of 25 patients who underwent MRI of the knee with both a PDFS sequence and T2 mapping and subse...

  12. Complex microwave conductivity of YBa2Cu3O7 in magnetic fields up to 500T

    International Nuclear Information System (INIS)

    Goettee, J.D.; Zerwekh, W.D.; Kudasov, Y.B.

    1994-01-01

    We have measured the complex conductivity of thin films of YBa 2 cu 3 O 7 (YBCO) superconductor down to temperatures of 4K and magnetic fields up to 500T. The highly oriented films were probed by 94 GHz radiation, with the external magnetic field applied perpendicular to the c-axis. These measurements allowed us to assign a value of 340 ± 40 for the upper critical field at T=O. The measurements were recently carried out at the pulsed field facility of the National High Magnetic Field Laboratory at Los Alamos using both Russian and American magnetic flux compression generators

  13. Preoperative prediction of sentinel lymph node metastasis in breast cancer based on radiomics of T2-weighted fat-suppression and diffusion-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yuhao; Mo, Xiaokai [Guangdong General Hospital/Guangdong Academy of Medical Sciences, Department of Radiology, Guangzhou, Guangdong Province (China); Shantou University Medical College, Graduate College, Shantou, Guangdong (China); Feng, Qianjin; Yang, Wei; Lu, Zixiao; Deng, Chunyan [Southern Medical University, The Guangdong Provincial Key Laboratory of Medical Image Processing, School of Biomedical Engineering, Guangzhou, Guangdong (China); Zhang, Lu; Lian, Zhouyang; Liu, Jing; Luo, Xiaoning; Pei, Shufang; Huang, Wenhui; Liang, Changhong; Zhang, Bin; Zhang, Shuixing [Guangdong General Hospital/Guangdong Academy of Medical Sciences, Department of Radiology, Guangzhou, Guangdong Province (China)

    2018-02-15

    To predict sentinel lymph node (SLN) metastasis in breast cancer patients using radiomics based on T{sub 2}-weighted fat suppression (T{sub 2}-FS) and diffusion-weighted MRI (DWI). We enrolled 146 patients with histologically proven breast cancer. All underwent pretreatment T{sub 2}-FS and DWI MRI scan. In all, 10,962 texture and four non-texture features were extracted for each patient. The 0.623 + bootstrap method and the area under the curve (AUC) were used to select the features. We constructed ten logistic regression models (orders of 1-10) based on different combination of image features using stepwise forward method. For T{sub 2}-FS, model 10 with ten features yielded the highest AUC of 0.847 in the training set and 0.770 in the validation set. For DWI, model 8 with eight features reached the highest AUC of 0.847 in the training set and 0.787 in the validation set. For joint T{sub 2}-FS and DWI, model 10 with ten features yielded an AUC of 0.863 in the training set and 0.805 in the validation set. Full utilisation of breast cancer-specific textural features extracted from anatomical and functional MRI images improves the performance of radiomics in predicting SLN metastasis, providing a non-invasive approach in clinical practice. (orig.)

  14. Can T1 w/T2 w ratio be used as a myelin-specific measure in subcortical structures? Comparisons between FSE-based T1 w/T2 w ratios, GRASE-based T1 w/T2 w ratios and multi-echo GRASE-based myelin water fractions.

    Science.gov (United States)

    Uddin, Md Nasir; Figley, Teresa D; Marrie, Ruth Ann; Figley, Chase R

    2018-03-01

    Given the growing popularity of T 1 -weighted/T 2 -weighted (T 1 w/T 2 w) ratio measurements, the objective of the current study was to evaluate the concordance between T 1 w/T 2 w ratios obtained using conventional fast spin echo (FSE) versus combined gradient and spin echo (GRASE) sequences for T 2 w image acquisition, and to compare the resulting T 1 w/T 2 w ratios with histologically validated myelin water fraction (MWF) measurements in several subcortical brain structures. In order to compare these measurements across a relatively wide range of myelin concentrations, whole-brain T 1 w magnetization prepared rapid acquisition gradient echo (MPRAGE), T 2 w FSE and three-dimensional multi-echo GRASE data were acquired from 10 participants with multiple sclerosis at 3 T. Then, after high-dimensional, non-linear warping, region of interest (ROI) analyses were performed to compare T 1 w/T 2 w ratios and MWF estimates (across participants and brain regions) in 11 bilateral white matter (WM) and four bilateral subcortical grey matter (SGM) structures extracted from the JHU_MNI_SS 'Eve' atlas. Although the GRASE sequence systematically underestimated T 1 w/T 2 w values compared to the FSE sequence (revealed by Bland-Altman and mountain plots), linear regressions across participants and ROIs revealed consistently high correlations between the two methods (r 2 = 0.62 for all ROIs, r 2 = 0.62 for WM structures and r 2 = 0.73 for SGM structures). However, correlations between either FSE-based or GRASE-based T 1 w/T 2 w ratios and MWFs were extremely low in WM structures (FSE-based, r 2 = 0.000020; GRASE-based, r 2 = 0.0014), low across all ROIs (FSE-based, r 2 = 0.053; GRASE-based, r 2 = 0.029) and moderate in SGM structures (FSE-based, r 2 = 0.20; GRASE-based, r 2 = 0.17). Overall, our findings indicated a high degree of correlation (but not equivalence) between FSE-based and GRASE-based T 1 w/T 2 w ratios, and low correlations between T 1 w/T 2 w ratios and MWFs. This

  15. Thermal properties of a large-bore cryocooled 10 T superconducting magnet for a hybrid magnet

    International Nuclear Information System (INIS)

    Ishizuka, M.; Hamajima, T.; Itou, T.; Sakuraba, J.; Nishijima, G.; Awaji, S.; Watanabe, K.

    2010-01-01

    A cryocooled 10 T superconducting magnet with a 360 mm room temperature bore has been developed for a hybrid magnet. The superconducting magnet cooled by four Gifford-McMahon cryocoolers has been designed to generate a magnetic field of 10 T. Since superconducting wires composed of coils were subjected to large hoop stress over 150 MPa and Nb 3 Sn superconducting wires particularly showed a low mechanical strength due to those brittle property, Nb 3 Sn wires strengthened by NbTi-filaments were developed for the cryocooled superconducting magnet. We have already reported that the hybrid magnet could generate the resultant magnetic field of 27.5 T by adding 8.5 T from the superconducting magnet and 19 T from a water-cooled Bitter resistive magnet, after the water-cooled resistive magnet was inserted into the 360 mm room temperature bore of the cryocooled superconducting magnet. When the hybrid magnet generated the field of 27.5 T, it achieved the high magnetic-force field (B x ∂Bz/∂z) of 4500 T 2 /m, which was useful for magneto-science in high fields such as materials levitation research. In this paper, we particularly focus on the cause that the cryocooled superconducting magnet was limited to generate the designed magnetic field of 10 T in the hybrid magnet operation. As a result, it was found that there existed mainly two causes as the limitation of the magnetic field generation. One was a decrease of thermal conductive passes due to exfoliation from the coil bobbin of the cooling flange. The other was large AC loss due to both a thick Nb 3 Sn layer and its large diameter formed on Nb-barrier component in Nb 3 Sn wires.

  16. Accuracy of magnetic resonance imaging in planning the osseous resection margins of bony tumours in the proximal femur: based on coronal T1-weighted versus STIR images

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Sarfraz; Stevenson, Jonathan; Mangham, Charles; Cribb, Gillian; Cool, Paul [Robert Jones and Agnes Hunt Orthopaedic Hospital, Department of Musculoskeletal Oncology, Oswestry, Shropshire (United Kingdom)

    2014-12-15

    Assessment of the extent of tumours using magnetic resonance imaging (MRI) is the basis for bone resection in limb-salvage surgery. We aimed to compare the accuracy of T1-weighted MRI and STIR sequences in measuring the extent of proximal femoral tumours, using the macroscopic specimens as the gold standard for comparison. We compared single coronal T1-weighted with STIR sequences in 34 proximal femoral tumours, using bivalved resected macroscopic tumours for comparison. After randomisation, four observers measured longitudinal osseous tumour extent using MRI and specimen photographs on two separate occasions, 3 weeks apart. There were 25 metastatic tumours, 8 chondrosarcomas and 1 myeloma. Eight patients presented with pathological fractures. The Pearson's correlation coefficient for comparison of T1 with macroscopic tumours was 0.91 (95 % confidence interval [CI]: 0.83 to 0.96) for all observers and 0.90 (95 % CI: 0.81 to 0.95) for STIR images. This difference was not statistically significant, and T1 and STIR sequence measurements had similar precision and accuracy. Bland-Altman plots showed T1-weighted imaging to be unbiased, whereas STIR sequences were biased and had systematic error. Moreover, STIR measurements overestimated tumour size by 6.4 mm (95 % CI: -26.9 to 39.7 mm) and 2 patients were outliers. T1 measurements were closer to the macroscopic measurements with a mean difference of 1.3 mm (95 % CI: -28.9 mm to 31.5 mm), with 3 patients falling outside of this. The variance was greater for STIR measurements. This difference between T1 and STIR measurements was statistically significant (p = 0.000003). The intra-observer reliability between separate measurements for MRI and specimen photographs achieved interclass correlation coefficients of 0.97, 0.96 and 0.95 (T1, STIR and macroscopic tumour respectively). T1 had greater interobserver correlation than for STIR and macroscopic tumour measurements (0.88 vs 0.85 and 0.85 respectively). These

  17. Altered carotid plaque signal among different repetition times on T1-weighted magnetic resonance plaque imaging with self-navigated radial-scan technique

    Energy Technology Data Exchange (ETDEWEB)

    Narumi, Shinsuke; Ohba, Hideki; Mori, Kiyofumi; Ohura, Kazumasa; Ono, Ayumi; Terayama, Yasuo [Iwate Medical University, Department of Neurology and Gerontology, Morioka (Japan); Sasaki, Makoto [Iwate Medical University, Advanced Medical Research Center, Morioka (Japan); Ogasawara, Kuniaki [Iwate Medical University, Department of Neurosurgery, Morioka (Japan); Hitomi, Jiro [Iwate Medical University, Department of Anatomy, Morioka (Japan)

    2010-04-15

    Magnetic resonance (MR) plaque imaging for carotid arteries is usually performed by using an electrocardiograph (ECG)-gating technique to eliminate pulsation-related artifacts, which can affect the plaque signals because of varied repetition time (TR) among patients. Hence, we investigated whether differences in TR causes signal alterations of the carotid plaque by using a non-gated plaque imaging technique. We prospectively examined 19 patients with carotid stenosis by using a T1-weighted self-navigated radial-scan technique with TRs of 500, 700, and 900 ms. The signal intensity of the carotid plaque was measured, and the contrast ratio (CR) relative to the adjacent muscle was calculated. CRs of the carotid plaques were 1.39 {+-} 0.39, 1.29 {+-} 0.29, and 1.23 {+-} 0.24 with TRs of 500, 700, and 900 ms, respectively, and were significantly different. Among the plaques, those with a hyperintensity signal (CR > 1.5) and moderate-intensity signal (CR 1.2-1.5) at 500 ms showed a TR-dependent signal decrease (hyperintensity plaques, 1.82 {+-} 0.26; 1.61 {+-} 0.19; and 1.48 {+-} 0.17; moderate-intensity plaques, 1.33 {+-} 0.08; 1.26 {+-} 0.08; and 1.19 {+-} 0.07), while those with an isointensity signal (CR < 1.2) remained unchanged regardless of TR (0.96 {+-} 0.12, 0.96 {+-} 0.11, and 0.97 {+-} 0.13). The signal intensity of the carotid plaque on T1-weighted imaging significantly varies among different TRs and tends to decrease with longer TR. MR plaque imaging with short and constant TR settings that the ECG-gating method cannot realize would be preferable for evaluating plaque characteristics. (orig.)

  18. Development of the 1.2T~1.5 T Permanent Magnetic Resonance Imaging Device and Its Application for Mouse Imaging

    Directory of Open Access Journals (Sweden)

    Guangxin Wang

    2015-01-01

    Full Text Available By improving the main magnet, gradient, and RF coils design technology, manufacturing methods, and inventing new magnetic resonance imaging (MRI special alloy, a cost-effective and small animal specific permanent magnet-type three-dimensional magnetic resonance imager was developed. The main magnetic field strength of magnetic resonance imager with independent intellectual property rights is 1.2~1.5 T. To demonstrate its effectiveness and validate the mouse imaging experiments in different directions, we compared the images obtained by small animal specific permanent magnet-type three-dimensional magnetic resonance imager with that obtained by using superconductor magnetic resonance imager for clinical diagnosis.

  19. Implementation of advanced feedback control algorithms for controlled resonant magnetic perturbation physics studies on EXTRAP T2R

    International Nuclear Information System (INIS)

    Frassinetti, L.; Olofsson, K.E.J.; Brunsell, P.R.; Drake, J.R.

    2011-01-01

    The EXTRAP T2R feedback system (active coils, sensor coils and controller) is used to study and develop new tools for advanced control of the MHD instabilities in fusion plasmas. New feedback algorithms developed in EXTRAP T2R reversed-field pinch allow flexible and independent control of each magnetic harmonic. Methods developed in control theory and applied to EXTRAP T2R allow a closed-loop identification of the machine plant and of the resistive wall modes growth rates. The plant identification is the starting point for the development of output-tracking algorithms which enable the generation of external magnetic perturbations. These algorithms will then be used to study the effect of a resonant magnetic perturbation (RMP) on the tearing mode (TM) dynamics. It will be shown that the stationary RMP can induce oscillations in the amplitude and jumps in the phase of the rotating TM. It will be shown that the RMP strongly affects the magnetic island position.

  20. Implementation of advanced feedback control algorithms for controlled resonant magnetic perturbation physics studies on EXTRAP T2R

    Science.gov (United States)

    Frassinetti, L.; Olofsson, K. E. J.; Brunsell, P. R.; Drake, J. R.

    2011-06-01

    The EXTRAP T2R feedback system (active coils, sensor coils and controller) is used to study and develop new tools for advanced control of the MHD instabilities in fusion plasmas. New feedback algorithms developed in EXTRAP T2R reversed-field pinch allow flexible and independent control of each magnetic harmonic. Methods developed in control theory and applied to EXTRAP T2R allow a closed-loop identification of the machine plant and of the resistive wall modes growth rates. The plant identification is the starting point for the development of output-tracking algorithms which enable the generation of external magnetic perturbations. These algorithms will then be used to study the effect of a resonant magnetic perturbation (RMP) on the tearing mode (TM) dynamics. It will be shown that the stationary RMP can induce oscillations in the amplitude and jumps in the phase of the rotating TM. It will be shown that the RMP strongly affects the magnetic island position.

  1. Abnormalities on diffusion-weighted magnetic resonance imaging in patients with transient ischemic attack

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Tomomi; Shibagaki, Yasuro [Ushiku Aiwa General Hospital, Ibaraki (Japan); Uchiyama, Shinichiro; Iwata, Makoto [Tokyo Women' s Medical Coll. (Japan)

    2003-03-01

    We studied abnormalities on diffusion-weighted magnetic resonance imaging (DWI) in patients with transient ischemic attack (TIA). Out of 18 consecutive TIA patients, 9 patients had relevant focal abnormalities on DWI. Among TIA patients, six patients were associated with atrial fibrillation (Af), and all of these patients had focal abnormalities on DWI as well. TIA patients with Af had significantly more frequent focal abnormalities on DWI than those without Af (p=0.009; Fisher's exact probability test). In addition, the duration of TIA symptoms was not related to the presence of focal abnormalities on DWI. These results indicate that embolic mechanism may cause focal abnormalities on DWI. DWI was more sensitive to detect responsible ischemic lesions in these patients than T2-weighted image or fluid-attenuated inversion recovery image. (author)

  2. Abnormalities on diffusion-weighted magnetic resonance imaging in patients with transient ischemic attack

    International Nuclear Information System (INIS)

    Nakamura, Tomomi; Shibagaki, Yasuro; Uchiyama, Shinichiro; Iwata, Makoto

    2003-01-01

    We studied abnormalities on diffusion-weighted magnetic resonance imaging (DWI) in patients with transient ischemic attack (TIA). Out of 18 consecutive TIA patients, 9 patients had relevant focal abnormalities on DWI. Among TIA patients, six patients were associated with atrial fibrillation (Af), and all of these patients had focal abnormalities on DWI as well. TIA patients with Af had significantly more frequent focal abnormalities on DWI than those without Af (p=0.009; Fisher's exact probability test). In addition, the duration of TIA symptoms was not related to the presence of focal abnormalities on DWI. These results indicate that embolic mechanism may cause focal abnormalities on DWI. DWI was more sensitive to detect responsible ischemic lesions in these patients than T2-weighted image or fluid-attenuated inversion recovery image. (author)

  3. Comparison between gadolinium-enhanced 2D T1-weighted gradient-echo and spin-echo sequences in the detection of active multiple sclerosis lesions on 3.0T MRI

    Energy Technology Data Exchange (ETDEWEB)

    Aymerich, F.X. [Hospital Universitari Vall d' Hebron, Universitat Autonoma de Barcelona, MR Unit. Department of Radiology (IDI), Barcelona (Spain); Universitat Politecnica de Catalunya - Barcelona Tech (UPC), Department of Automatic Control (ESAII), Barcelona (Spain); Auger, C.; Alcaide-Leon, P.; Pareto, D.; Huerga, E.; Corral, J.F.; Mitjana, R.; Rovira, A. [Hospital Universitari Vall d' Hebron, Universitat Autonoma de Barcelona, MR Unit. Department of Radiology (IDI), Barcelona (Spain); Sastre-Garriga, J.; Montalban, X. [Hospital Universitari Vall d' Hebron, Universitat Autonoma de Barcelona, Centre d' Esclerosi Multiple de Catalunya (Cemcat), Department of Neurology/Neuroimmunology, Barcelona (Spain)

    2017-04-15

    To compare the sensitivity of enhancing multiple sclerosis (MS) lesions in gadolinium-enhanced 2D T1-weighted gradient-echo (GRE) and spin-echo (SE) sequences, and to assess the influence of visual conspicuity and laterality on detection of these lesions. One hundred MS patients underwent 3.0T brain MRI including gadolinium-enhanced 2D T1-weighted GRE and SE sequences. The two sets of contrast-enhanced scans were evaluated in random fashion by three experienced readers. Lesion conspicuity was assessed by the image contrast ratio (CR) and contrast-to-noise ratio (CNR). The intracranial region was divided into four quadrants and the impact of lesion location on detection was assessed in each slice. Six hundred and seven gadolinium-enhancing MS lesions were identified. GRE images were more sensitive for lesion detection (0.828) than SE images (0.767). Lesions showed a higher CR in SE than in GRE images, whereas the CNR was higher in GRE than SE. Most misclassifications occurred in the right posterior quadrant. The gadolinium-enhanced 2D T1-weighted GRE sequence at 3.0T MRI enables detection of enhancing MS lesions with higher sensitivity and better lesion conspicuity than 2D T1-weighted SE. Hence, we propose the use of gadolinium-enhanced GRE sequences rather than SE sequences for routine scanning of MS patients at 3.0T. (orig.)

  4. Comparison of axial T1 spin-echo and T1 fat-saturation magnetic resonance imaging techniques in the diagnosis of chondromalacia patellae.

    Science.gov (United States)

    Vanarthos, W J; Pope, T L; Monu, J U

    1994-12-01

    To test the diagnostic value of T1 spin-echo and T1 fat-saturated magnetic resonance images (MRIs), we reviewed axial T1-weighted images with and without fat saturation in 20 patients with clinically suspected chondromalacia of the patella. All scans were obtained on 1.5-MR units. The scans were randomly ordered and reviewed independently at different times by two radiologists without knowledge of the arthroscopy results. The sensitivity of the individual techniques for detecting grade 3 or 4 chondromalacia patellae was 92% for fat-saturated axial T1-weighted images alone, and 67% for axial T1-weighted images without fat saturation. The sensitivity of the combined techniques was 100% for grades 3 and 4 and 90% for all grades (0 to 4). Chondromalacia patellae is diagnosed more accurately by using T1 fat saturation than by using T1 spin-echo images. With a combination of the two techniques, accuracy is 90% to 100%.

  5. T2-weighted images are superior to other MR image types for the determination of diffuse intrinsic pontine glioma intratumoral heterogeneity.

    Science.gov (United States)

    Harward, Stephen; Harrison Farber, S; Malinzak, Michael; Becher, Oren; Thompson, Eric M

    2018-03-01

    Diffuse intrinsic pontine glioma (DIPG) remains the main cause of death in children with brain tumors. Given the inefficacy of numerous peripherally delivered agents to treat DIPG, convection enhanced delivery (CED) of therapeutic agents is a promising treatment modality. The purpose of this study was to determine which MR imaging type provides the best discrimination of intratumoral heterogeneity to guide future stereotactic implantation of CED catheters into the most cellular tumor regions. Patients ages 18 years or younger with a diagnosis of DIPG from 2000 to 2015 were included. Radiographic heterogeneity index (HI) of the tumor was calculated by measuring the standard deviation of signal intensity of the tumor (SD Tumor ) normalized to the genu of the corpus callosum (SD Corpus Callosum ). Four MR image types (T2-weighted, contrast-enhanced T1-weighted, FLAIR, and ADC) were analyzed at several time points both before and after radiotherapy and chemotherapy. HI values across these MR image types were compared and correlated with patient survival. MR images from 18 patients with DIPG were evaluated. The mean survival ± standard deviation was 13.8 ± 13.7 months. T2-weighted images had the highest HI (mean ± SD, 5.1 ± 2.5) followed by contrast-enhanced T1-weighted images (3.7 ± 1.5), FLAIR images (3.0 ± 1.1), and ADC maps (1.6 ± 0.4). ANOVA demonstrated that HI values were significantly higher for T2-weighted images than FLAIR (p image HI values increased, while FLAIR and ADC HI values decreased. Univariate and multivariate analyses did not reveal a relationship between HI values and patient survival (p > 0.05). For children with DIPG, T2-weighted MRI demonstrates the greatest signal intensity variance suggesting tumor heterogeneity. Within this heterogeneity, T2-weighted signal hypointensity is known to correlate with increased cellularity and thus may represent a putative target for CED catheter placement in future clinical

  6. Simultaneous T1 and T2 Brain Relaxometry in Asymptomatic Volunteers using Magnetic Resonance Fingerprinting.

    Science.gov (United States)

    Badve, Chaitra; Yu, Alice; Rogers, Matthew; Ma, Dan; Liu, Yiying; Schluchter, Mark; Sunshine, Jeffrey; Griswold, Mark; Gulani, Vikas

    2015-12-01

    Magnetic resonance fingerprinting (MRF) is a method of image acquisition that produces multiple MR parametric maps from a single scan. Here, we describe the normal range and progression of MRF-derived relaxometry values with age in healthy individuals. 56 normal volunteers (ages 11-71 years, M:F 24:32) were scanned. Regions of interest were drawn on T 1 and T 2 maps in 38 areas, including lobar and deep white matter, deep gray nuclei, thalami and posterior fossa structures. Relaxometry differences were assessed using a forward stepwise selection of a baseline model including either gender, age, or both, where variables were included if they contributed significantly (p<0.05). Additionally, differences in regional anatomy, including comparisons between hemispheres and between anatomical subcomponents, were assessed by paired t-tests. Using this protocol, MRF-derived T 1 and T 2 in frontal WM regions were found to increase in with age, while occipital and temporal regions remained relatively stable. Deep gray nuclei, including substantia nigra, were found to have age-related decreases in relaxometry. Gender differences were observed in T 1 and T 2 of temporal regions, cerebellum and pons. Males were also found to have more rapid age-related changes in frontal and parietal WM. Regional differences were identified between hemispheres, between genu and splenium of corpus callosum, and between posteromedial and anterolateral thalami. In conclusion, MRF quantification can measure relaxometry trends in healthy individuals that are in agreement with current understanding of neuroanatomy and neurobiology, and has the ability to uncover additional patterns that have not yet been explored.

  7. Fast T1-weighted imaging using GRASE sequence for the female pelvis

    International Nuclear Information System (INIS)

    Dohke, Masako; Watanabe, Yuji; Kumashiro, Masayuki; Amoh, Yoshiki; Ishimori, Takayoshi; Oda, Kazushige; Okumura, Akira; Koike, Shinji; Dodo, Yoshihiro

    1998-01-01

    GRASE sequence, a combination of TSE and gradient echo, has been developed as a fast T 2 -weighted imaging technique. We have modified the GRASE sequence to be used for fast T 1 -weighted imaging of the female pelvis. In this article, we compared image quality and incidence of artifacts between T 1 -weighted GRASE images and conventional T 1 -weighted SE images. In a phantom study, signal-to-noise ratio was inferior in the GRASE images relative to corresponding on SE images. Susceptibility and chemical shift artifacts seen in GRASE images were seen with almost equal incidence in SE and TSE images. In a clinical study, we compared GRASE images with SE images in six patients with endometrial cysts and four patients with dermoid cysts. The overall image quality obtained with GRASE sequence was satisfactory in all patients and was almost identical with that obtained with SE sequence. GRASE images demonstrated endometrial cysts and dermoid cysts as clearly as did SE images. T 1 -weighted GRASE imaging, however, has a relatively long TE (35 ms) for T 1 -weighted images, which makes the signal intensity of urine and uterine endometrium with long T 2 values higher than in SE images. In conclusion, GRASE sequence can be used for fast T 1 -weighted imaging of the female pelvis because of short imaging time. (author)

  8. Computer-aided detection of prostate cancer in T2-weighted MRI within the peripheral zone

    Science.gov (United States)

    Rampun, Andrik; Zheng, Ling; Malcolm, Paul; Tiddeman, Bernie; Zwiggelaar, Reyer

    2016-07-01

    In this paper we propose a prostate cancer computer-aided diagnosis (CAD) system and suggest a set of discriminant texture descriptors extracted from T2-weighted MRI data which can be used as a good basis for a multimodality system. For this purpose, 215 texture descriptors were extracted and eleven different classifiers were employed to achieve the best possible results. The proposed method was tested based on 418 T2-weighted MR images taken from 45 patients and evaluated using 9-fold cross validation with five patients in each fold. The results demonstrated comparable results to existing CAD systems using multimodality MRI. We achieved an area under the receiver operating curve (A z ) values equal to 90.0%+/- 7.6% , 89.5%+/- 8.9% , 87.9%+/- 9.3% and 87.4%+/- 9.2% for Bayesian networks, ADTree, random forest and multilayer perceptron classifiers, respectively, while a meta-voting classifier using average probability as a combination rule achieved 92.7%+/- 7.4% .

  9. Complex microwave conductivity of YBa2Cu3O7 in magnetic fields up to 500 T

    International Nuclear Information System (INIS)

    Bykov, A.I.; Dolotenko, M.I.; Fowler, C.M.; Freeman, B.L.; Goettee, J.D.; King, J.C.; Kolokolchikov, N.P.; Kudasov, Yu.B.; Lewis, W.; Marshall, B.R.; Papatheofanis, B.J.; Platonov, V.V.; Rodriguez, P.J.; Tatsenko, O.M.; Veeser, L.R.; Zerwekh, W.D.

    1995-01-01

    The complex microwave conductivity of thin, oriented YBa 2 Cu 3 O 7 films was measured at 94 GHz in pulsed, ultrahigh-magnetic fields up to 500 T. The c-axis of the film was perpendicular to the magnetic field. We estimate the upper critical field of the film at absolute zero as B c2 (0)=340±40 T. Dynamics of the transition into a normal state and connection with previous measurements of the reversibility line are discussed. (orig.)

  10. T1 weighted brain images at 7 Tesla unbiased for Proton Density, T2* contrast and RF coil receive B1 sensitivity with simultaneous vessel visualization.

    Science.gov (United States)

    Van de Moortele, Pierre-François; Auerbach, Edwards J; Olman, Cheryl; Yacoub, Essa; Uğurbil, Kâmil; Moeller, Steen

    2009-06-01

    At high magnetic field, MR images exhibit large, undesirable signal intensity variations commonly referred to as "intensity field bias". Such inhomogeneities mostly originate from heterogeneous RF coil B(1) profiles and, with no appropriate correction, are further pronounced when utilizing rooted sum of square reconstruction with receive coil arrays. These artifacts can significantly alter whole brain high resolution T(1)-weighted (T(1)w) images that are extensively utilized for clinical diagnosis, for gray/white matter segmentation as well as for coregistration with functional time series. In T(1) weighted 3D-MPRAGE sequences, it is possible to preserve a bulk amount of T(1) contrast through space by using adiabatic inversion RF pulses that are insensitive to transmit B(1) variations above a minimum threshold. However, large intensity variations persist in the images, which are significantly more difficult to address at very high field where RF coil B(1) profiles become more heterogeneous. Another characteristic of T(1)w MPRAGE sequences is their intrinsic sensitivity to Proton Density and T(2)(*) contrast, which cannot be removed with post-processing algorithms utilized to correct for receive coil sensitivity. In this paper, we demonstrate a simple technique capable of producing normalized, high resolution T(1)w 3D-MPRAGE images that are devoid of receive coil sensitivity, Proton Density and T(2)(*) contrast. These images, which are suitable for routinely obtaining whole brain tissue segmentation at 7 T, provide higher T(1) contrast specificity than standard MPRAGE acquisitions. Our results show that removing the Proton Density component can help in identifying small brain structures and that T(2)(*) induced artifacts can be removed from the images. The resulting unbiased T(1)w images can also be used to generate Maximum Intensity Projection angiograms, without additional data acquisition, that are inherently registered with T(1)w structural images. In addition

  11. Development and Evaluation of a Semi-automated Segmentation Tool and a Modified Ellipsoid Formula for Volumetric Analysis of the Kidney in Non-contrast T2-Weighted MR Images.

    Science.gov (United States)

    Seuss, Hannes; Janka, Rolf; Prümmer, Marcus; Cavallaro, Alexander; Hammon, Rebecca; Theis, Ragnar; Sandmair, Martin; Amann, Kerstin; Bäuerle, Tobias; Uder, Michael; Hammon, Matthias

    2017-04-01

    Volumetric analysis of the kidney parenchyma provides additional information for the detection and monitoring of various renal diseases. Therefore the purposes of the study were to develop and evaluate a semi-automated segmentation tool and a modified ellipsoid formula for volumetric analysis of the kidney in non-contrast T2-weighted magnetic resonance (MR)-images. Three readers performed semi-automated segmentation of the total kidney volume (TKV) in axial, non-contrast-enhanced T2-weighted MR-images of 24 healthy volunteers (48 kidneys) twice. A semi-automated threshold-based segmentation tool was developed to segment the kidney parenchyma. Furthermore, the three readers measured renal dimensions (length, width, depth) and applied different formulas to calculate the TKV. Manual segmentation served as a reference volume. Volumes of the different methods were compared and time required was recorded. There was no significant difference between the semi-automatically and manually segmented TKV (p = 0.31). The difference in mean volumes was 0.3 ml (95% confidence interval (CI), -10.1 to 10.7 ml). Semi-automated segmentation was significantly faster than manual segmentation, with a mean difference = 188 s (220 vs. 408 s); p T2-weighted MR data delivers accurate and reproducible results and was significantly faster than manual segmentation. Applying a modified ellipsoid formula quickly provides an accurate kidney volume.

  12. Efficacy of T2*-Weighted Gradient-Echo MRI in Early Diagnosis of Cerebral Venous Thrombosis with Unilateral Thalamic Lesion

    Directory of Open Access Journals (Sweden)

    Shingo Mitaki

    2013-01-01

    Full Text Available Cerebral venous thrombosis (CVT is an uncommon cause of stroke with diverse etiologies and varied clinical presentations. Because of variability in clinical presentation and neuroimaging, CVT remains a diagnostic challenge. Recently, some studies have highlighted the value of T2*-weighted gradient-echo MRI (T2*WI in the diagnosis of CVT. We report the case of a 79-year-old woman with CVT due to a hypercoagulable state associated with cancer. On the initial T2-weighted image (T2WI, there was a diffuse high-intensity lesion in the right thalamus, extending into the posterior limb of the internal capsule and midbrain. T2*WI showed diminished signal and enlargement of the right basilar vein and the vein of Galen. Even though there is a wide range of differential diagnoses in unilateral thalamic lesions, and a single thalamus lesion is a rare entity of CVT, based on T2*WI findings we could make an early diagnosis and perform treatment. Our case report suggests that T2*WI could detect thrombosed veins and be a useful method of early diagnosis in CVT.

  13. Evaluation of Renal Oxygenation Level Changes after Water Loading Using Susceptibility-Weighted Imaging and T2* Mapping.

    Science.gov (United States)

    Ding, Jiule; Xing, Wei; Wu, Dongmei; Chen, Jie; Pan, Liang; Sun, Jun; Xing, Shijun; Dai, Yongming

    2015-01-01

    To assess the feasibility of susceptibility-weighted imaging (SWI) while monitoring changes in renal oxygenation level after water loading. Thirty-two volunteers (age, 28.0 ± 2.2 years) were enrolled in this study. SWI and multi-echo gradient echo sequence-based T2(*) mapping were used to cover the kidney before and after water loading. Cortical and medullary parameters were measured using small regions of interest, and their relative changes due to water loading were calculated based on baseline and post-water loading data. An intraclass correlation coefficient analysis was used to assess inter-observer reliability of each parameter. A receiver operating characteristic curve analysis was conducted to compare the performance of the two methods for detecting renal oxygenation changes due to water loading. Both medullary phase and medullary T2(*) values increased after water loading (p T2(*) changes (p > 0.05). Interobserver reliability was excellent for the T2(*) values, good for SWI cortical phase values, and moderate for the SWI medullary phase values. The area under receiver operating characteristic curve of the SWI medullary phase values was 0.85 and was not different from the medullary T2(*) value (0.84). Susceptibility-weighted imaging enabled monitoring changes in the oxygenation level in the medulla after water loading, and may allow comparable feasibility to detect renal oxygenation level changes due to water loading compared with that of T2(*) mapping.

  14. Pelvic endometriosis: a comparison between low-field (0.2 T) and high-field (1.5 T) magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Minaif, Karine; Ajzen, Sergio [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. of Imaging Diagnosis]. E-mail: kminaif@uol.com.br; Shigueoka, David Carlos; Minami, Cintia Cristina Satie; Sales, Danilo Moulin; Szejnfeld, Jacob [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. of Imaging Diagnosis. Unit of Abdomen; Ruano, Jose Maria Cordeiro [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. of General Gynecology. Sector of Videlaparoscopy; Noguti, Alberto Sinhiti [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. of General Gynecology

    2008-11-15

    Objective: to compare low-field (0.2 T) with high-field (1.5 T) magnetic resonance imaging in the assessment of pelvic endometriosis and adenomyosis. Materials and methods: twenty-seven female patients with clinically suspected endometriosis were prospectively evaluated by means of high-field and low-field magnetic resonance imaging. The reading of the images was performed by a single radiologist, initiating by the low-field, followed by the high-field images. High-field magnetic resonance imaging was utilized as the golden-standard. Results: among the 27 patients included in the present study, 18 (66.7%) had some type of lesion suggesting the presence of endometriosis demonstrated at high-field images. In 14 of these patients the diagnosis was correctly established by low-field magnetic resonance imaging. Endometriomas, tubal lesions, and endometriotic foci > 7 mm identified at the high-field images were also identified at low-field images with 100% accuracy, sensitivity and specificity. Among the nine patients diagnosed with adenomyosis by high-field images, eight were correctly diagnosed by low-field images with 88.9% accuracy, specificity and sensitivity. Conclusion: low-field magnetic resonance imaging demonstrated a low sensitivity in the detection of small endometriotic foci, high sensitivity in the detection of endometriomas and large endometriotic foci, and high accuracy in the detection of adenomyosis when compared with high-field magnetic resonance imaging. (author)

  15. Pelvic endometriosis: a comparison between low-field (0.2 T) and high-field (1.5 T) magnetic resonance imaging

    International Nuclear Information System (INIS)

    Minaif, Karine; Ajzen, Sergio; Shigueoka, David Carlos; Minami, Cintia Cristina Satie; Sales, Danilo Moulin; Szejnfeld, Jacob; Ruano, Jose Maria Cordeiro; Noguti, Alberto Sinhiti

    2008-01-01

    Objective: to compare low-field (0.2 T) with high-field (1.5 T) magnetic resonance imaging in the assessment of pelvic endometriosis and adenomyosis. Materials and methods: twenty-seven female patients with clinically suspected endometriosis were prospectively evaluated by means of high-field and low-field magnetic resonance imaging. The reading of the images was performed by a single radiologist, initiating by the low-field, followed by the high-field images. High-field magnetic resonance imaging was utilized as the golden-standard. Results: among the 27 patients included in the present study, 18 (66.7%) had some type of lesion suggesting the presence of endometriosis demonstrated at high-field images. In 14 of these patients the diagnosis was correctly established by low-field magnetic resonance imaging. Endometriomas, tubal lesions, and endometriotic foci > 7 mm identified at the high-field images were also identified at low-field images with 100% accuracy, sensitivity and specificity. Among the nine patients diagnosed with adenomyosis by high-field images, eight were correctly diagnosed by low-field images with 88.9% accuracy, specificity and sensitivity. Conclusion: low-field magnetic resonance imaging demonstrated a low sensitivity in the detection of small endometriotic foci, high sensitivity in the detection of endometriomas and large endometriotic foci, and high accuracy in the detection of adenomyosis when compared with high-field magnetic resonance imaging. (author)

  16. Unusual Presentation of Popliteal Cyst on Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Ohishi

    2016-01-01

    Full Text Available Popliteal cyst commonly presents as an ellipsoid mass with uniform low signal intensity on T1-weighted magnetic resonance images and high signal intensity on T2-weighted images. Here, we describe a popliteal cyst with unusual appearance on magnetic resonance imaging, including heterogeneous intermediate signal intensity on T2-weighted images. Arthroscopic cyst decompression revealed that the cyst was filled with necrotic synovial villi, indicative of rheumatoid arthritis. Arthroscopic enlargement of unidirectional valvular slits with synovectomy was useful for the final diagnosis and treatment.

  17. Serial contrast-enhanced magnetic resonance and magnetization transfer in the study of patients with multiple sclerosis

    International Nuclear Information System (INIS)

    Rovira, A.; Alonso, J.; Cucurella, G.; Nos, C.; Tintore, M.; Pedraza, S.; Rio, J.; Montalban, X.

    1997-01-01

    To demonstrate the changes in the magnetization transfer ratio (MTR) of different demyelinating plaques, correlating them with the baseline values in T1-weighted contrast-enhanced magnetic resonance (MR) sequences in order to relate them more closely to the underlying disease. The study was based on 33 demyelinating plaques obtained from six patients clinically diagnosed as having remitting-recurring multiple sclerosis (MS). All the patients underwent two MR studies at a 3 to 5-month interval, including contrast-enhanced T1 and T2- weighted sequences and magnetization transfer images. The latter were used to calculate the MTR for each of the demyelinating plaques included in the study. The statistical analysis of the results obtained revealed statistically significant between initial MTR values and those of subsequent T1-weighted sequences. The MTR demonstrate significant differences between plaques according to contrast-enhanced T1-weigh tes sequences, probably indicating variable degrees of edema, demyelination and tissue destruction. These differences should be taken into account to enable the use of T1-weighted sequences to quantify the lesion load in MS patients. (Author) 35 refs

  18. T2 Magnetic Resonance Assay: Overview of Available Data and Clinical Implications

    Directory of Open Access Journals (Sweden)

    Ioannis M. Zacharioudakis

    2018-04-01

    Full Text Available Invasive candidiasis is a common healthcare-associated infection with a high mortality rate that can exceed 60% in cases of septic shock. Blood culture performance is far from ideal, due to the long time to positivity and suppression by antifungal agents. The T2 Magnetic Resonance (T2MR assay is an FDA-approved qualitative molecular diagnostic method that can detect and speciate the 5 most common Candida spp.; namely, Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis, and Candida krusei, in approximately 5 h. In a multicenter clinical trial that included both a prospective and a contrived arm to represent the full range of clinically relevant concentrations of Candida spp., T2MR demonstrated a sensitivity and specificity of 91.1% and 98.1%, respectively. The utility of T2MR in candidemia depends on the prevalence of disease in each clinical setting. In intensive care units and other high-prevalence settings, the incorporation of T2MR in diagnostic algorithms is very appealing. T2MR is expected to allow timely initiation of antifungal therapy and help with anti-fungal stewardship. In low-prevalence settings, the positive predictive value of T2MR might not be enough to justify initiation of antifungal treatment in itself. The performance of T2MR has not been studied in cases of deep-seated candidiasis. Despite some promising evidence in published clinical trials, further studies are needed to determine the performance of T2MR in invasive candidiasis without candidemia. Overall, experience with T2MR in everyday clinical practice is evolving but, in the right setting, this technology is expected to provide “actionable information” for the management of patients evaluated for candidemia.

  19. T1 weighted Brain Images at 7 Tesla Unbiased for Proton Density, T2* contrast and RF Coil Receive B1 Sensitivity with Simultaneous Vessel Visualization

    Science.gov (United States)

    Van de Moortele, Pierre-François; Auerbach, Edwards J.; Olman, Cheryl; Yacoub, Essa; Uğurbil, Kâmil; Moeller, Steen

    2009-01-01

    At high magnetic field, MR images exhibit large, undesirable signal intensity variations commonly referred to as “intensity field bias”. Such inhomogeneities mostly originate from heterogeneous RF coil B1 profiles and, with no appropriate correction, are further pronounced when utilizing rooted sum of square reconstruction with receive coil arrays. These artifacts can significantly alter whole brain high resolution T1-weighted (T1w) images that are extensively utilized for clinical diagnosis, for gray/white matter segmentation as well as for coregistration with functional time series. In T1 weighted 3D-MPRAGE sequences, it is possible to preserve a bulk amount of T1 contrast through space by using adiabatic inversion RF pulses that are insensitive to transmit B1 variations above a minimum threshold. However, large intensity variations persist in the images, which are significantly more difficult to address at very high field where RF coil B1 profiles become more heterogeneous. Another characteristic of T1w MPRAGE sequences is their intrinsic sensitivity to Proton Density and T2* contrast, which cannot be removed with post-processing algorithms utilized to correct for receive coil sensitivity. In this paper, we demonstrate a simple technique capable of producing normalized, high resolution T1w 3D-MPRAGE images that are devoid of receive coil sensitivity, Proton Density and T2* contrast. These images, which are suitable for routinely obtaining whole brain tissue segmentation at 7 Tesla, provide higher T1 contrast specificity than standard MPRAGE acquisitions. Our results show that removing the Proton Density component can help identifying small brain structures and that T2* induced artifacts can be removed from the images. The resulting unbiased T1w images can also be used to generate Maximum Intensity Projection angiograms, without additional data acquisition, that are inherently registered with T1w structural images. In addition, we introduce a simple technique

  20. MFTF-α+T end plug magnet design

    International Nuclear Information System (INIS)

    Srivastava, V.C.; O'Toole, J.A.

    1983-01-01

    The conceptual design of the end-plug magnets for MFTF-α+T is described. MFTF-α+ T is a near-term upgrade of MFTF-B, which features new end plugs to improve performance. The Fusion Engineering Design Center has performed the engineering design of MFTF-α+T under the overall direction of Lawrence Livermore National Laboratory. Each end plug consists of two Yin-Yang pairs, each with approx.2.5:1 mirror ratio and approx.5-T peak field on axis; two transition coils; and a recircularizing solenoid. This paper describes the end-plug magnet system functional requirements and presents a conceptual design that meets them. The peak field at the windings of the end-plug coils is approx.6-T. These coils are designed using the NbTi MFTF-B conductor and cooled by a 4.2K liquid helium bath. All the end-plug magnets are designed to operate in the cryostable mode with adequate quench protection for safety. Shielding requirements are stated and a summary of heat loads is provided. Field and force calculations are discussed. The field on axis is shown to meet the functional requirements. Force resultants are reported in terms of winding running loads and resultant coil forces are also given. The magnet structural support is described. A trade study to determine the optimum end-cell coil internal nuclear shield thickness and the resulting coil size based on minimizing the end-cell life cycle cost is summarized

  1. Diffusion-Weighted Magnetic Resonance Imaging in Monitoring Rectal Cancer Response to Neoadjuvant Chemoradiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Barbaro, Brunella, E-mail: bbarbaro@rm.unicatt.it [Department of Bioimaging and Radiological Sciences, Catholic University School of Medicine, Rome (Italy); Vitale, Renata; Valentini, Vincenzo; Illuminati, Sonia [Department of Bioimaging and Radiological Sciences, Catholic University School of Medicine, Rome (Italy); Vecchio, Fabio M. [Department of Pathology, Catholic University School of Medicine, Rome (Italy); Rizzo, Gianluca [Department of Surgery, Catholic University School of Medicine, Rome (Italy); Gambacorta, Maria Antonietta [Department of Bioimaging and Radiological Sciences, Catholic University School of Medicine, Rome (Italy); Coco, Claudio; Crucitti, Antonio; Persiani, Roberto; Sofo, Luigi [Department of Surgery, Catholic University School of Medicine, Rome (Italy); Bonomo, Lorenzo [Department of Bioimaging and Radiological Sciences, Catholic University School of Medicine, Rome (Italy)

    2012-06-01

    Purpose: To prospectively monitor the response in patients with locally advanced nonmucinous rectal cancer after chemoradiotherapy (CRT) using diffusion-weighted magnetic resonance imaging. The histopathologic finding was the reference standard. Methods and Materials: The institutional review board approved the present study. A total of 62 patients (43 men and 19 women; mean age, 64 years; range, 28-83) provided informed consent. T{sub 2}- and diffusion-weighted magnetic resonance imaging scans (b value, 0 and 1,000 mm{sup 2}/s) were acquired before, during (mean 12 days), and 6-8 weeks after CRT. We compared the median apparent diffusion coefficients (ADCs) between responders and nonresponders and examined the associations with the Mandard tumor regression grade (TRG). The postoperative nodal status (ypN) was evaluated. The Mann-Whitney/Wilcoxon two-sample test was used to evaluate the relationships among the pretherapy ADCs, extramural vascular invasion, early percentage of increases in ADCs, and preoperative ADCs. Results: Low pretreatment ADCs (<1.0 Multiplication-Sign 10{sup -3}mm{sup 2}/s) were correlated with TRG 4 scores (p = .0011) and associated to extramural vascular invasion with ypN+ (85.7% positive predictive value for ypN+). During treatment, the mean percentage of increase in tumor ADC was significantly greater in the responders than in the nonresponders (p < .0001) and a >23% ADC increase had a 96.3% negative predictive value for TRG 4. In 9 of 16 complete responders, CRT-related tumor downsizing prevented ADC evaluations. The preoperative ADCs were significantly different (p = .0012) between the patients with and without downstaging (preoperative ADC {>=}1.4 Multiplication-Sign 10{sup -3}mm{sup 2}/s showed a positive and negative predictive value of 78.9% and 61.8%, respectively, for response assessment). The TRG 1 and TRG 2-4 groups were not significantly different. Conclusion: Diffusion-weighted magnetic resonance imaging seems to be a promising

  2. Decrease in the cortical intensity on T2-weighted magnetic resonance imaging with aging in normal subjects

    International Nuclear Information System (INIS)

    Imon, Yukari; Murata, Yoshio; Kajima, Toshio; Nakamura, Shigenobu; Yamaguchi, Shinya

    1997-01-01

    We reported previously that Low T 2 intensity areas (LIAs) are more common in patients with central nervous system (CNS) diseases than in those with no such diseases, and that the occurrence of LIAs increases with aging. To determine a relationship between the intensity changes and aging, we investigated the intensity of the cerebral cortex in 26 normal Japanese individuals. Measurements of brain MRIs were performed with a Signa Advantage apparatus at 1.5 tesla. T 2 -weighted images were obtained using the spin-echo pulse sequences. On our laboratory console, we measured signal intensities in the regions of interest in the prefrontal, motor, sensory, parietal, temporal, or occipital cortex, and in the frontal white matter. To remove the effect of the system gain settings on signal intensity, that of cerebrospinal fluid was used as reference according to the method of Pujol et al. The average intensity in the temporal and prefrontal cortices was the highest, followed in order by the parietal, sensory, motor, and occipital cortices. The intensity in the temporal and parietal cortices decreased significantly with aging, and that in the motor and sensory cortices had a tendency to decrease with aging. The intensity in the motor and sensory cortices of the elderly subjects and that in the occipital cortex throughout all ages were lower than that in the prefrontal white matter, which would result in the appearance of LIAs. The average intensity of each cerebral cortex was inversely related to the non-heme iron content previously reported. It is likely that the difference in intensity among the cortices reflects variations of the non-heme iron content, and that the change in intensity with aging could be due to the increase in such cortical senile changes as that of microglia, astroglia, and senile plaques, which contain iron or iron-related proteins. The temporal cortex is most susceptible to senile changes. (K.H.)

  3. Orthodontic springs and auxiliary appliances: assessment of magnetic field interactions associated with 1.5 T and 3 T magnetic resonance systems

    International Nuclear Information System (INIS)

    Kemper, J.; Priest, A.N.; Adam, G.; Schulze, D.; Kahl-Nieke, B.; Klocke, A.

    2007-01-01

    The objective of this paper is to evaluate magnetic field interactions at 1.5 and 3 T for 20 orthodontic devices used for fixed orthodontic therapy. Twenty springs and auxiliary parts made from varying ferromagnetic alloys were tested for magnetic field interactions in the static magnetic field at 1.5 and 3 T. Magnetic translational force F z (in millinewtons) was evaluated by determining the deflection angle β [American Society for Testing and Materials (ASTM standard test method)]. Magnetic-field-induced rotational force F rot was qualitatively determined using a five-point scale. β was found to be >45 in 13(15) devices at 1.5(3) T and translational force F z exceeded gravitational force F g on the particular object [F z 10.17-261.4 mN (10.72-566.4 mN) at 1.5(3) T]. F z was found to be up to 24.1(47.5)-fold higher than F g at 1.5(3) T. Corresponding to this, F rot on the objects was shown to be high at both field strengths (≥ +3). Three objects (at 1.5 T) and one object (at 3 T) showed deflection angles rot was found to be ≥ +3 at both field strengths. For the remaining objects, β was below 45 and torque measurements ranged from 0 to +2. Of 20 objects investigated for magnetic field interactions at 1.5(3) T, 13(15) were unsafe in magnetic resonance (MR), based on the ASTM criteria of F z . The implications of these results for orthodontic patients undergoing MRI are discussed. (orig.)

  4. Orthodontic springs and auxiliary appliances: assessment of magnetic field interactions associated with 1.5 T and 3 T magnetic resonance systems

    Energy Technology Data Exchange (ETDEWEB)

    Kemper, J.; Priest, A.N.; Adam, G. [University Medical Center of Hamburg-Eppendorf, Clinic of Diagnostic and Interventional Radiology, Hamburg (Germany); Schulze, D. [University Hospital of Freiburg, Department of Oral and Maxillofacial Surgery, Freiburg (Germany); Kahl-Nieke, B.; Klocke, A. [University Medical Center of Hamburg-Eppendorf, Department of Orthodontics, Hamburg (Germany)

    2007-02-15

    The objective of this paper is to evaluate magnetic field interactions at 1.5 and 3 T for 20 orthodontic devices used for fixed orthodontic therapy. Twenty springs and auxiliary parts made from varying ferromagnetic alloys were tested for magnetic field interactions in the static magnetic field at 1.5 and 3 T. Magnetic translational force F{sub z} (in millinewtons) was evaluated by determining the deflection angle {beta} [American Society for Testing and Materials (ASTM standard test method)]. Magnetic-field-induced rotational force F{sub rot} was qualitatively determined using a five-point scale. {beta} was found to be >45 in 13(15) devices at 1.5(3) T and translational force F{sub z} exceeded gravitational force F{sub g} on the particular object [F{sub z} 10.17-261.4 mN (10.72-566.4 mN) at 1.5(3) T]. F{sub z} was found to be up to 24.1(47.5)-fold higher than F{sub g} at 1.5(3) T. Corresponding to this, F{sub rot} on the objects was shown to be high at both field strengths ({>=} +3). Three objects (at 1.5 T) and one object (at 3 T) showed deflection angles <45 , but F{sub rot} was found to be {>=} +3 at both field strengths. For the remaining objects, {beta} was below 45 and torque measurements ranged from 0 to +2. Of 20 objects investigated for magnetic field interactions at 1.5(3) T, 13(15) were unsafe in magnetic resonance (MR), based on the ASTM criteria of F{sub z}. The implications of these results for orthodontic patients undergoing MRI are discussed. (orig.)

  5. SU-E-T-227: Could the Alpha/Beta Ratio Change in a Strong Magnetic Field?

    Energy Technology Data Exchange (ETDEWEB)

    Pang, G [Odette Cancer Centre, 2075 Bayview Avenue, Toronto M4N 3M5, Canada and Sunnybrook Research Institute and Departments of Radiation Oncology and Medical Biophysics, University of Toronto, Toronto (Canada)

    2015-06-15

    Purpose: Magnetic resonance imaging (MRI) is being integrated into radiotherapy delivery for MRI-guided radiotherapy. The presence of a strong magnetic field from a MRI machine during radiotherapy delivery presents a new challenge since the trajectories of electrons liberated by ionizing radiation in patients are strongly dependent on the applied magnetic field. The purpose of this work is to explore the potential effect of a strong magnetic field on the α/β ratio, an important radiobiological parameter in radiotherapy. Methods: Based on the theory of dual radiation action, the α/β ratio can be expressed by an integral of the product of two microdosimetry quantities γ(x) and t(x), where γ(x) is the probability that two energy transfers, a distance x apart, results in a lesion, and t(x) is the proximity function, which is the energy-weighted point-pair distribution of distances between energy transfer points in a track. The quantity t(x) depends on the applied magnetic field. An analytical approach has been used to derive a formula that can be used to calculate the α/β ratio in an extremely strong magnetic field. Results: The α/β ratio has been evaluated in the special case when the applied magnetic field approaches infinity, which gives the upper limit of the potential change of the α/β ratio due to the presence of a strong magnetic field. For V79 Chinese hamster cells it has been shown that the α/β ratio could be increased by 2.90 times for Pd-103, 2.97 times for I-125 and about 2.3 times for Co-60 sources when the applied magnetic field approaches infinity. Conclusion: It has been shown theoretically that the α/β ratio can change in a strong magnetic field, and there could be up to a nearly three-fold increase in the α/β ratio, depending on the strength of the applied magnetic field, the cell type and the radiation used.

  6. Magnetic anisotropy study of UGe2in a static high magnetic field

    International Nuclear Information System (INIS)

    Sakon, T; Saito, S; Koyama, K; Awaji, S; Sato, I; Nojima, T; Watanabe, K; Motokawa, M; Sato, N K

    2006-01-01

    UGe 2 has orthorhombic C mmm crystalline symmetry and shows ferromagnetic Heavy-Fermion (HF) Superconductor, which provides superconductivity under pressure in the range from 1.0 GPa to 1.5 GPa. Magnetic field dependence of magnetization shows strong magnetic anisotropy. When a magnetic field is applied parallel to easy axis (a-axis), magnetization presents ferromagnetic behavior. At 4.2 K, which is much lower than the Curie temperature T c = 54 K. Spontaneous magnetization is 1.4 μ B /U, and the magnetization gradually increase with increasing field. On the contrary, when a field is applied parallel to hard axis (b-axis or c-axis), magnetization increases linearly with increasing magnetic field. As for H//b-axis, magnetization is 0.23 μ B /U even at 27 T. Magnetocrystalline anisotropy constant is obtained as 230 [T μ B ] 3.4[kJ/kg] at 4.2 K. This value is comparable with rare-earth magnet Nd 2 Fe 17 , which is typical strongly correlated ferromagnet

  7. Comparison of spin echo T1-weighted sequences versus fast spin-echo proton density-weighted sequences for evaluation of meniscal tears at 1.5 T

    International Nuclear Information System (INIS)

    Wolff, Andrew B.; Pesce, Lorenzo L.; Wu, Jim S.; Smart, L.R.; Medvecky, Michael J.; Haims, Andrew H.

    2009-01-01

    At our institution, fast spin-echo (FSE) proton density (PD) imaging is used to evaluate articular cartilage, while conventional spin-echo (CSE) T1-weighted sequences have been traditionally used to characterize meniscal pathology. We sought to determine if FSE PD-weighted sequences are equivalent to CSE T1-weighted sequences in the detection of meniscal tears, obviating the need to perform both sequences. We retrospectively reviewed the records of knee arthroscopies performed by two arthroscopy-focused surgeons from an academic medical center over a 2-year period. The preoperative MRI images were interpreted independently by two fellowship-trained musculoskeletal radiologists who graded the sagittal CSE T1 and FSE PD sequences at different sittings with grades 1-5, where 1 = normal meniscus, 2 = probable normal meniscus, 3 indeterminate, 4 = probable torn meniscus, and 5 = torn meniscus. Each meniscus was divided into an anterior and posterior half, and these halves were graded separately. Operative findings provided the gold standard. Receiver operating characteristic (ROC) analysis was performed to compare the two sequences. There were 131 tears in 504 meniscal halves. Using ROC analysis, the reader 1 area under curve for FSE PD was significantly better than CSE T1 (0.939 vs. 0.902, >95% confidence). For reader 2, the difference met good criteria for statistical non-inferiority but not superiority (0.913 for FSE PD and 0.908 for CSE T1; >95% non-inferiority for difference at most of -0.027). FSE PD-weighted sequences, using our institutional protocol, are not inferior to CSE T1-weighted sequences for the detection of meniscal tears and may be superior. (orig.)

  8. Comparison of T1-weighted fast spin-echo and T1-weighted fluid-attenuated inversion recovery images of the lumbar spine at 3.0 Tesla

    International Nuclear Information System (INIS)

    Lavdas, Eleftherios; Vlychou, Marianna; Arikidis, Nikos; Kapsalaki, Eftychia; Roka, Violetta; Fezoulidis, Ioannis V.

    2010-01-01

    Background: T1-weighted fluid-attenuated inversion recovery (FLAIR) sequence has been reported to provide improved contrast between lesions and normal anatomical structures compared to T1-weighted fast spin-echo (FSE) imaging at 1.5T regarding imaging of the lumbar spine. Purpose: To compare T1-weighted FSE and fast T1-weighted FLAIR imaging in normal anatomic structures and degenerative and metastatic lesions of the lumbar spine at 3.0T. Material and Methods: Thirty-two consecutive patients (19 females, 13 males; mean age 44 years, range 30-67 years) with lesions of the lumbar spine were prospectively evaluated. Sagittal images of the lumbar spine were obtained using T1-weighted FSE and fast T1-weighted FLAIR sequences. Both qualitative and quantitative analyses measuring the signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and relative contrast (ReCon) between degenerative and metastatic lesions and normal anatomic structures were conducted, comparing these sequences. Results: On quantitative evaluation, SNRs of cerebrospinal fluid (CSF), nerve root, and fat around the root of fast T1-weighted FLAIR imaging were significantly lower than those of T1-weighted FSE images (P<0.001). CNRs of normal spinal cord/CSF and disc herniation/ CSF for fast T1-weighted FLAIR images were significantly higher than those for T1-weighted FSE images (P<0.001). ReCon of normal spinal cord/CSF, disc herniation/CSF, and vertebral lesions/CSF for fast T1-weighted FLAIR images were significantly higher than those for T1-weighted FSE images (P<0.001). On qualitative evaluation, it was found that CSF nulling and contrast at the spinal cord (cauda equina)/CSF interface for T1-weighted FLAIR images were significantly superior compared to those for T1-weighted FSE images (P<0.001), and the disc/spinal cord (cauda equina) interface was better for T1-weighted FLAIR images (P<0.05). Conclusion: The T1-weighted FLAIR sequence may be considered as the preferred lumbar spine imaging

  9. An age estimation method using brain local features for T1-weighted images.

    Science.gov (United States)

    Kondo, Chihiro; Ito, Koichi; Kai Wu; Sato, Kazunori; Taki, Yasuyuki; Fukuda, Hiroshi; Aoki, Takafumi

    2015-08-01

    Previous statistical analysis studies using large-scale brain magnetic resonance (MR) image databases have examined that brain tissues have age-related morphological changes. This fact indicates that one can estimate the age of a subject from his/her brain MR image by evaluating morphological changes with healthy aging. This paper proposes an age estimation method using local features extracted from T1-weighted MR images. The brain local features are defined by volumes of brain tissues parcellated into local regions defined by the automated anatomical labeling atlas. The proposed method selects optimal local regions to improve the performance of age estimation. We evaluate performance of the proposed method using 1,146 T1-weighted images from a Japanese MR image database. We also discuss the medical implication of selected optimal local regions.

  10. [3T magnetic resonance T2 mapping for evaluation of cartilage repair after matrix-associated autologous chondrocyte transplantation].

    Science.gov (United States)

    Zhang, Jun; Xu, Xian; Li, Xue; Chen, Min; Dong, Tian-Ming; Zuo, Pan-Li; An, Ning-Yu

    2015-01-01

    To assess the value of magnetic resonance imaging (MRI) T2 mapping in quantitative evaluation of cartilage repair following matrix-associated autologous chondrocyte transplantation (MACT). Six patients (with 9 plug cartilages) following MACT underwent MRI on a 3.0 Tesla MR scan system at 3, 6 and 12 months after the surgery. The full-thickness and zonal areas (deep and superficial layers) T2 values were calculated for the repaired cartilage and control cartilage. The mean T2 values of the repaired cartilage after MACT were significantly higher than that of the control cartilages at 3 and 6 months (PT2 values of the superficial layers were significantly higher than those of the deep layers in the repaired cartilages (PT2 values of the repaired cartilages decreased significantly over time at 6 and 12 months as compared to those at 3 months after the surgery (PT2 mapping can serve as an important modality for assessing the repair of the articular cartilage following MACT.

  11. Signal intensity in T2' magnetic resonance imaging is related to brain glioma grade

    International Nuclear Information System (INIS)

    Saitta, Laura; Castellan, Lucio; Heese, Oliver; Westphal, Manfred; Foerster, Ann-Freya; Siemonsen, Susanne; Fiehler, Jens; Goebell, Einar; Matschke, Jakob

    2011-01-01

    T2' values reflect the presence of deoxyhaemoglobin related to high local oxygen extraction. We assessed the feasibility of T2' imaging to display regions with high metabolic activity in brain gliomas. MRI was performed in 25 patients (12 female; median age 46 years; range 2-69) with brain gliomas with additional T2 and T2* sequences. T2' maps were derived from T2 and T2*. Dynamic susceptibility weighted contrast (DSC) perfusion was performed in 12/25 patients. Images were visually assessed by two readers and five ROIs were evaluated for each patient. Pearson correlation, Mann-Whitney and Kruskal-Wallis tests were applied for statistical analysis. Three patients were not further evaluated because of artefacts. Mean values of high-grade (III-IV) gliomas showed significantly lower T2' values than low-grade (II) gliomas (p < 0.001). An inverse relationship was observed between rCBV and sqr (T2') (r = -0.463, p < 0.001). No correlation was observed between T2' and rCBV for grade II tumours (r = 0.038; p = 0.875). High-grade tumours revealed lower T2' values, presumably because of higher oxygen consumption in proliferating tissue. Our results indicate that T2' imaging can be used as an alternative to DSC perfusion in the detection of subtle deviations in tumour metabolism. (orig.)

  12. Studies on improvement of diagnosis of neurosurgical lesions by magnetic resonance imaging (MRI), 2

    International Nuclear Information System (INIS)

    Shimizu, Kotoyuki

    1989-01-01

    Findings of magnetic resonance (MRI) imaging in 46 patients with sellar or parasellar mass were reviewed and compared with those of concurrently available X-ray CT. Intrasellar contents, the hypothalamic pituitary region, adjacent brain stem, optic nerves, and the surrounding cerebrospinal fluid were clearly depicted on T1-weighted images. The cavernous sinus and blood vessels, including the Willis circle, were visualized on T2-weighted images. In detecting pituitary macroadenoma, MRI seemed to be the most userful modality, because it was superior to CT in identifying abnormal changes of the infundibulum, diaphragma sellae, cavernous sinus and optic chiasm. Macroadenoma of the pituitary gland was usually isointense to the normal cerebral cortex on T1- and T2-weighted images. T1- and T2-weighted relaxation times for pituitary adenoma were slightly prolonged. The normal pituitary gland was distinguishable from adenomatous tissues. For microadenoma, MRI failed to show lesions or erosion of the sellar floor. Craniopharyngioma, meningioma of the tuberculum sellae, hypothalamic tumor, such as glioma and germinoma, and the other parasellar masses were clearly visualized on MRI. MRI was superior to CT in detecting tumor and its involvement, but inferior in detecting presence of calcification. T1-weighted imaging was useful in identifing the presence of intratumoral hemorrhage. Cysts of craniopharyngioma had various appearances on T1-weighted images. High signal cyst intensity corresponded to a high cholesterol content or the presence of methemoglobin. MRI depicted empty sella. The intrasellar content had the same appearance as that of the cerebrospinal fluid space, and the flattened pituitary gland and pituitary stalk were detected on T1-weighted images. (N.K.)

  13. Parasellar meningiomas: magnetic resonance imaging findings

    International Nuclear Information System (INIS)

    Santos, Alair Augusto S.M.D. dos; Fontes, Cristina Asvolinsque P.

    2001-01-01

    We reviewed 22 cases of patients with parasellar meningiomas evaluated with magnetic resonance imaging (MRI) in private clinics of the cities of Niteroi and Rio de Janeiro, Rio de Janeiro State, Brazil. Our aim was to characterize the imaging findings in this type of tumor. MRI scanners with 0.5 and 1.0 Tesla magnets were used for the acquisition of multiplanar T1-weighted (pre-and post-gadolinium administration) and T2-weighted images. The main symptoms observed were headache and visual disturbances. Hyperprolactinaemia was observed in only one patient. The most frequent imaging finding was a parasellar mass which appeared hypointense on T1-weighted and hyperintense on T2-weighted images, and enhanced intensively after gadolinium administration. MRI is useful to demonstrate the lesion and to asses the damage to adjacent structures, particularly when the patient presents visual disturbances due to involvement of the cavernous sinuses. (author)

  14. Lumbosacral lipoma : gadolinium-enhanced fat saturation T1 weighted MR image is necessary?

    International Nuclear Information System (INIS)

    Yoon, Man Won; Kim, Hyun Chul; Chung, Tae Woong; Seo, Jeong Jin; Chung, Gwang Woo; Kim, Yun Hyeon; Kim, Jae Kyu; Park, Jin Gyoon; Kang, Heoung Keun

    1999-01-01

    To evaluate the usefulness of contrast-enhanced fat saturation T1-weighted imaging for the evaluation of spinal lipoma, compared with clinical symptoms and surgical findings. Ten patients with lipomyelomeningocele, confirmed by surgery, were included in this study. In all cases, conventional spin echo T1-and T2-weighted MR imaging, and contrast-enhanced fat saturation T1-weighted imaging was performed to evaluate clinical symptoms, the position of the conus medullaris, the presence of cord tethering, and associated anomalies, and to compare the relative usefulness of the techniques. All ten patients were suffering from lipomyelomeningocele without filum terminale fibrolipoma or intradural lipoma. All cases were associated with cord tethering. As associated anomalies, there were seven cases of syringomyelia without hydrocephalus or anorectal anomaly. To evaluate the position of the spinal conus and the presence of cord tethering, conventional T1-weighted imaging was more useful than the contrast-enhanced fat saturation equivalent. In patients with early-stage spinal lipoma, MRI is useful for evaluation of the causes and position of cord tethering and associated anomalies Our results suggest that contrast-enhanced fat saturation T1-weighted images do not provide additional information concerning spinal lipoma, and that for the diagnosis of this condition, conventional T1 and T2-weighted images are more useful than those obtained by contrast-enhanced fat saturation T1-weighted imaging

  15. Carcinoma of the uterine cervix. High-resolution turbo spin-echo MR imaging with contrast-enhanced dynamic scanning and T2-weighting

    International Nuclear Information System (INIS)

    Abe, Y.; Yamashita, Y.; Namimoto, T.; Takahashi, M.; Katabuchi, H.; Tanaka, N.; Okamura, H.

    1998-01-01

    Purpose: To compare high-resolution contrast-enhanced (Gd-DTPA) dynamic MR imaging with T2-weighted turbo spin-echo (TSE) imaging in the evaluation of uterine cervical carcinoma. Material and Methods: Thirty-two patients with cervical carcinoma underwent MR imaging on a 1.5 T superconductive unit to have the extension of the disease assessed before treatment. A phased-array coil was used in all patients. In 25 patients, surgical confirmation of the diagnosis was obtained after imaging. Radiation therapy was selected for the remaining 7 patients with advanced carcinoma. Qualitative and quantitative image analyses were also performed. Results: The cervical carcinomas showed maximum contrast in the cervical stroma and myometrium in the early dynamic phase. The tumor/cervical-stroma contrast in the early dynamic phase obtained with the T1-weighted TSE technique (contrast-to-noise ratio 22.6) was significantly higher than that obtained in T2-weighted TSE imaging (contrast-to-noise ratio 4.3). In the evaluation of parametrial invasion, the accuracy of T2-weighted imaging was 71.8% and contrast-enhanced dynamic imaging 81.2%. Conclusion: High-resolution contrast-enhanced (Gd-DTPA) dynamic MR imaging in cervical cancer offers improved tumor/cervical-stroma contrast and provides useful information on parametrial invasion. (orig.)

  16. Driven equilibrium (drive) MR imaging of the cranial nerves V-VIII: comparison with the T2-weighted 3D TSE sequence

    Energy Technology Data Exchange (ETDEWEB)

    Ciftci, E. E-mail: eciftcis7@hotmail.com; Anik, Yonca; Arslan, Arzu; Akansel, Gur; Sarisoy, Tahsin; Demirci, Ali

    2004-09-01

    Purpose: The aim of this study is to evaluate the efficacy of the driven equilibrium radio frequency reset pulse (DRIVE) on image quality and nerve detection when used in adjunction with T2-weighted 3D turbo spin-echo (TSE) sequence. Materials and methods: Forty-five patients with cranial nerve symptoms referable to the cerebellopontine angle (CPA) were examined using a T2-weighted 3D TSE pulse sequence with and without DRIVE. MR imaging was performed on a 1.5-T MRI scanner. In addition to the axial resource images, reformatted oblique sagittal, oblique coronal and maximum intensity projection (MIP) images of the inner ear were evaluated. The nerve identification and image quality were graded for the cranial nerves V-VIII as well as inner ear structures. These structures were chosen because fluid-solid interfaces existed due to the CSF around (the cranial nerves V-VIII) or the endolymph within (the inner ear structures). Statistical analysis was performed using the Wilcoxon test. P<0.05 was considered significant. Results: The addition of the DRIVE pulse shortens the scan time by 25%. T2-weighted 3D TSE sequence with DRIVE performed slightly better than the T2-weighted 3D TSE sequence without DRIVE in identifying the individual nerves. The image quality was also slightly better with DRIVE. Conclusion: The addition of the DRIVE pulse to the T2-weighted 3D TSE sequence is preferable when imaging the cranial nerves surrounded by the CSF, or fluid-filled structures because of shorter scan time and better image quality due to reduced flow artifacts.

  17. Driven equilibrium (drive) MR imaging of the cranial nerves V-VIII: comparison with the T2-weighted 3D TSE sequence

    International Nuclear Information System (INIS)

    Ciftci, E.; Anik, Yonca; Arslan, Arzu; Akansel, Gur; Sarisoy, Tahsin; Demirci, Ali

    2004-01-01

    Purpose: The aim of this study is to evaluate the efficacy of the driven equilibrium radio frequency reset pulse (DRIVE) on image quality and nerve detection when used in adjunction with T2-weighted 3D turbo spin-echo (TSE) sequence. Materials and methods: Forty-five patients with cranial nerve symptoms referable to the cerebellopontine angle (CPA) were examined using a T2-weighted 3D TSE pulse sequence with and without DRIVE. MR imaging was performed on a 1.5-T MRI scanner. In addition to the axial resource images, reformatted oblique sagittal, oblique coronal and maximum intensity projection (MIP) images of the inner ear were evaluated. The nerve identification and image quality were graded for the cranial nerves V-VIII as well as inner ear structures. These structures were chosen because fluid-solid interfaces existed due to the CSF around (the cranial nerves V-VIII) or the endolymph within (the inner ear structures). Statistical analysis was performed using the Wilcoxon test. P<0.05 was considered significant. Results: The addition of the DRIVE pulse shortens the scan time by 25%. T2-weighted 3D TSE sequence with DRIVE performed slightly better than the T2-weighted 3D TSE sequence without DRIVE in identifying the individual nerves. The image quality was also slightly better with DRIVE. Conclusion: The addition of the DRIVE pulse to the T2-weighted 3D TSE sequence is preferable when imaging the cranial nerves surrounded by the CSF, or fluid-filled structures because of shorter scan time and better image quality due to reduced flow artifacts

  18. Interobserver and test-retest reproducibility of T1ρ and T2 mesurements of lumber intervertebral discs by 3t magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Yeon Hwa; Yoon, Choon Sik; Eun, Na Lae; Kim, Sung Jin; Chung, Tae Sub [Dept. of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); Hwang, Moon Jung [GE Health Care, Seoul (Korea, Republic of); Yoo, Hanna [Biostatistics Collaboration Lab, Yonsei University College of Medicine, Seoul (Korea, Republic of); Peter, Robert D. [GE Health Care, Milwaukee (United States); Lee, Young Han; Suh, Jin Suck [Dept. of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2016-11-15

    To investigate the interobserver and test-retest reproducibility of T1ρ and T2 measurements of lumbar intervertebral discs using 3T magnetic resonance imaging (MRI). This study included a total of 51 volunteers (female, 26; male, 25; mean age, 54 ± 16.3 years) who underwent lumbar spine MRI with a 3.0 T scanner. Amongst these subjects, 40 underwent repeat T1ρ and T2 measurement acquisitions with identical image protocol. Two observers independently performed the region of interest measurements in the nuclei pulposi of the discs from L1-2 through L5-S1 levels. Statistical analysis was performed using intraclass correlation coefficient (ICC) with a two-way random model of absolute agreement. Comparison of the ICC values was done after acquisition of ICC values using Z test. Statistical significance was defined as p value < 0.05. The ICCs of interobserver reproducibility were 0.951 and 0.672 for T1ρ and T2 mapping, respectively. The ICCs of test-retest reproducibility (40 subjects) for T1ρ and T2 measurements were 0.922 and 0.617 for observer A and 0.914 and 0.628 for observer B, respectively. In the comparison of the aforementioned ICCs, ICCs of interobserver and test-retest reproducibility for T1ρ mapping were significantly higher than T2 mapping (p < 0.001). The interobserver and test-retest reproducibility of T1ρ mapping were significantly higher than those of T2 mapping for the quantitative assessment of nuclei pulposi of lumbar intervertebral discs.

  19. Fogging on T2-weighted MR after acute ischaemic stroke: how often might this occur and what are the implications?

    International Nuclear Information System (INIS)

    O'Brien, P.; Sellar, R.J.; Wardlaw, J.M.

    2004-01-01

    ''Fogging'' is the temporary loss of visibility of an infarct on CT which occurs in the subacute phase at about 2 weeks after stroke. It occurs in up to 40% of medium to large infarcts on CT. It is unclear whether or how often fogging occurs on T2-weighted MR, but if it does occur, it can cause underestimation of true infarct size. This study examined the possible frequency and time scale of ''fogging'' on T2-weighted MR. We conducted a blinded, independent review of prospectively collected MR scans from patients with symptoms of cortical ischaemic stroke, scanned sequentially up to 7 weeks after stroke. On each scan maximum infarct area was measured, and the infarct extent and swelling were coded on a validated scale. ''Fogging'' was suggested by reduced infarct extent between initial and subsequent scans. In 30 patients (with 74 scans) there was some apparent ''fogging'' in 50% of patients between 6 and 36 days (median 10 days) after stroke. Reduction in infarct extent on T2-weighted MR which may be attributed to ''fogging'' occurs in a significant proportion of patients with cortical infarcts. This may lead to an underestimation of true final infarct extent. This suggests that true infarct extent on T2-weighted MR can probably only be assessed on scans obtained beyond 7 weeks after stroke. (orig.)

  20. Magnetic resonance imaging of infectious myositis

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Ji Young; Kim, Jee Young; Kim, Sang Heum; Jung, Youn Ju; Cha, Eun Suk; Park, Joung Mi; Park, Young Ha [The Catholic Univ., College of Medicine, Suwon (Korea, Republic of)

    1998-09-01

    To describe the findings of magnetic resonance imaging in infectious myositis and to determine their value for differentiation between ruberculous and bacterial myositis. Magnetic resonance images of ten proven cases of infectious myositis (five tuberculous and five bacterial) were retrospectively reviewed in the light of clinical and laboratory findings. On the basis of magnetic resonance images, signal intensity of the mass, the presence or absence of an abscess, signal intensity of the peripheral wall, patterns of contrast enhancement, and associated findings were evaluated. Compared with those of bacterial myositis, the symptoms of tuberculous myositis lasted longer but there were no difinite local inflammatory signs. In three of five cases of bacterial myositis there were specific medical records;trauma in two cases and systemic lupus erythematosus in one. All tuberculous myositis cases involved a single muscle, but bacterial myositis affected multipe muscles in three cases(60%). All but one case showed a mass in the involved muscles. In one bacterial case, there was diffuse swelling in the involved muscle. On T1-weighted images, eight infectious cases showed low signal intensity;two, of the bactrerial type, showed subtle increased signal intensity. all cases demonstrated high signal intensity on t2-weighted images. The signal intensity of peripheral wall was slightly increased on T1-weighted images, but low on T2-weighted. In four cases there was associated cellulitis, and in one case each, adjacent joint effusion and deep vein thrombosis were seen. After gadolinium infusion, peripheral rim enhancement was noted in nine cases and heterogeneous enhancement in one. After magnetic resonance imaging of infectious myositis, the characteristic finding was an abscessed lesion, with the peripheral wall showing high signal intensity on T1-weighted images and low signal intensity on T2 weighted. Although we found it difficult to differentiate bacterial from tuberculous

  1. Magnetic resonance imaging of infectious myositis

    International Nuclear Information System (INIS)

    Yun, Ji Young; Kim, Jee Young; Kim, Sang Heum; Jung, Youn Ju; Cha, Eun Suk; Park, Joung Mi; Park, Young Ha

    1998-01-01

    To describe the findings of magnetic resonance imaging in infectious myositis and to determine their value for differentiation between ruberculous and bacterial myositis. Magnetic resonance images of ten proven cases of infectious myositis (five tuberculous and five bacterial) were retrospectively reviewed in the light of clinical and laboratory findings. On the basis of magnetic resonance images, signal intensity of the mass, the presence or absence of an abscess, signal intensity of the peripheral wall, patterns of contrast enhancement, and associated findings were evaluated. Compared with those of bacterial myositis, the symptoms of tuberculous myositis lasted longer but there were no difinite local inflammatory signs. In three of five cases of bacterial myositis there were specific medical records;trauma in two cases and systemic lupus erythematosus in one. All tuberculous myositis cases involved a single muscle, but bacterial myositis affected multipe muscles in three cases(60%). All but one case showed a mass in the involved muscles. In one bacterial case, there was diffuse swelling in the involved muscle. On T1-weighted images, eight infectious cases showed low signal intensity;two, of the bactrerial type, showed subtle increased signal intensity. all cases demonstrated high signal intensity on t2-weighted images. The signal intensity of peripheral wall was slightly increased on T1-weighted images, but low on T2-weighted. In four cases there was associated cellulitis, and in one case each, adjacent joint effusion and deep vein thrombosis were seen. After gadolinium infusion, peripheral rim enhancement was noted in nine cases and heterogeneous enhancement in one. After magnetic resonance imaging of infectious myositis, the characteristic finding was an abscessed lesion, with the peripheral wall showing high signal intensity on T1-weighted images and low signal intensity on T2 weighted. Although we found it difficult to differentiate bacterial from tuberculous

  2. T2-weighted high-intensity signals in the basal ganglia as an interesting image finding in Unverricht-Lundborg disease.

    Science.gov (United States)

    Korja, Miikka; Ferlazzo, Edoardo; Soilu-Hänninen, Merja; Magaudda, Adriana; Marttila, Reijo; Genton, Pierre; Parkkola, Riitta

    2010-01-01

    We conducted a search for white matter changes (WMCs) in 13 Unverricht-Lundborg disease patients and compared the prevalence of WMCs in these patients to age-matched long-term epileptics and healthy controls. ULD patients had significantly more T2-weighted high-intensity signals on MRI than control subjects, due to the increased prevalence of these signals in the basal ganglia. Interestingly, ULD patients with the basal ganglia changes were overweight. Basal ganglia T2-weighted high-intensity signals are novel findings in ULD. 2009 Elsevier B.V. All rights reserved.

  3. Assessing the effect of weight and weight loss in obese persons with type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Bradley Curtis

    2008-10-01

    Full Text Available Bradley Curtis1, Risa P Hayes1, Sheri Fehnel2, Laurie Zografos21Global Health Outcomes, Eli Lilly and Co, Indianapolis, IN, USA; 2RTI Health Solutions, Research Triangle Park, NC, USAAbstract: The objective of this study was to assess specific areas of life in which obesity affects individuals with type 2 diabetes mellitus (T2DM, and changes that obese persons with T2DM experience with weight loss of varying degrees. Thirty in-depth interviews were conducted in persons identified as: age ≥40 years, diagnosed with T2DM for ≥2 years, on oral antihyperglycemic medications >3 months, BMI 30–35 kg/m2, having attempted to lose weight in the last 2 years. Participants (60% female, mean age 53 years, 53% Caucasian, mean BMI 32.2 kg/m2 agreed that 5% weight loss, while not reflective of an ultimate goal, would be meaningful and important; benefits were expected to accrue in physical functioning, self-confidence, blood glucose levels, and motivation to keep losing weight. Participants reported the greatest effect of weight loss on energy, physical activity, mobility, pain, and clothes/appearance. Participants reported weight affecting mood, with feelings of depression and frustration most commonly described. This research indicates that weight loss is likely to affect health-related quality of life in obese individuals with T2DM. Given the purported weight loss benefits of many emerging diabetic medications, it will be important to include measures of weight-related quality of life in future clinical trials of these agents.Keywords: health-related quality of life, obesity, type 2 diabetes, weight loss, patient-reported outcomes

  4. Endometrial cancer with cervical stromal invasion: diagnostic accuracy of diffusion-weighted and dynamic contrast enhanced MR imaging at 3T

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Gigin; Lu, Hsin-Ying [Chang Gung Memorial Hospital at Linkou and Chang Gung University, Department of Medical Imaging and Intervention, Institute for Radiological Research, Guishan, Taoyuan (China); Chang Gung Memorial Hospital at Linkou, Clinical Phenome Center, Guishan, Taoyuan (China); Huang, Yu-Ting; Lin, Yu-Chun; Ng, Shu-Hang; Ng, Koon-Kwan [Chang Gung Memorial Hospital at Linkou and Chang Gung University, Department of Medical Imaging and Intervention, Institute for Radiological Research, Guishan, Taoyuan (China); Chao, Angel; Lai, Chyong-Huey [Chang Gung Memorial Hospital at Linkou and Chang Gung University, Department of Obstetrics and Gynecology and Gynecologic Cancer Research Center, Guishan, Taoyuan (China); Yang, Lan-Yan [Chang Gung Memorial Hospital at Linkou and Chang Gung University, Clinical Trial Center, Guishan, Taoyuan (China); Wu, Ren-Chin [Chang Gung Memorial Hospital at Linkou and Chang Gung University, Department of Pathology, Guishan, Taoyuan (China)

    2017-05-15

    To compare the diagnostic accuracy of diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging for detecting cervical stromal invasion in endometrial cancer. Eighty-three consecutive women with endometrial cancer underwent preoperative evaluation in a 3-T unit, including T2-weighted, DW (b = 0 and 1000 s/mm{sup 2}), and DCE MR imaging. Two radiologists independently assessed presence of cervical stromal invasion, with histopathological reference as gold standard. For assessing cervical stromal invasion, the diagnostic accuracy, sensitivity, and specificity, respectively for Reader 1/Reader 2, were as follows: DW MR imaging - 95.2 %/91.6 %, 91.7 %/100 %, and 95.8 %/90.1 %; DCE MR imaging - 91.6 %/88 %, 58.3 %/50 %, and 97.2 %/94.4 %. The diagnostic performance of DW MR imaging (Reader 1: areas under the receiver operating characteristic curve (AUC) = 0.98; Reader 2: AUC = 0.97) was significantly higher than that of DCE MR imaging (p = 0.009 for Reader 2) or T2-weighted MR imaging (Reader 1: p = 0.006; Reader 2: p = 0.013). Patients with cervical stromal invasion showed a significantly greater canal width (p < 0.0001) and myometrial invasion extent (p = 0.006). DW MR imaging has superior diagnostic performance compared with DCE MR imaging in the detection of cervical stromal invasion. (orig.)

  5. Dynamic T{sub 2}-mapping during magnetic resonance guided high intensity focused ultrasound ablation of bone marrow

    Energy Technology Data Exchange (ETDEWEB)

    Waspe, Adam C.; Looi, Thomas; Mougenot, Charles; Amaral, Joao; Temple, Michael; Sivaloganathan, Siv; Drake, James M. [Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada); Philips Healthcare Canada, Markham, ON, L6C 2S3 (Canada); Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada); Department of Applied Mathematics, University of Waterloo, Waterloo, ON, N2L 3G1 (Canada); Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada)

    2012-11-28

    Focal bone tumor treatments include amputation, limb-sparing surgical excision with bone reconstruction, and high-dose external-beam radiation therapy. Magnetic resonance guided high intensity focused ultrasound (MR-HIFU) is an effective non-invasive thermotherapy for palliative management of bone metastases pain. MR thermometry (MRT) measures the proton resonance frequency shift (PRFS) of water molecules and produces accurate (<1 Degree-Sign C) and dynamic (<5s) thermal maps in soft tissues. PRFS-MRT is ineffective in fatty tissues such as yellow bone marrow and, since accurate temperature measurements are required in the bone to ensure adequate thermal dose, MR-HIFU is not indicated for primary bone tumor treatments. Magnetic relaxation times are sensitive to lipid temperature and we hypothesize that bone marrow temperature can be determined accurately by measuring changes in T{sub 2}, since T{sub 2} increases linearly in fat during heating. T{sub 2}-mapping using dual echo times during a dynamic turbo spin-echo pulse sequence enabled rapid measurement of T{sub 2}. Calibration of T{sub 2}-based thermal maps involved heating the marrow in a bovine femur and simultaneously measuring T{sub 2} and temperature with a thermocouple. A positive T{sub 2} temperature dependence in bone marrow of 20 ms/ Degree-Sign C was observed. Dynamic T{sub 2}-mapping should enable accurate temperature monitoring during MR-HIFU treatment of bone marrow and shows promise for improving the safety and reducing the invasiveness of pediatric bone tumor treatments.

  6. High signal of the striatum in sporadic Creutzfeldt-Jakob disease: sequential change on T2-weighted MRI

    International Nuclear Information System (INIS)

    Uemura, A.; O'uchi, T.; Sakamoto, T.; Yashiro, N.

    2002-01-01

    The object of this study is to describe the sequential change of high signal of the striatum on T2-weighted MRI in sporadic Creutzfeldt-Jakob disease (CJD). Three cases of autopsy-proven sporadic CJD and a total of 18 serial MR images are included in this study. The degree of high signal of the striatum on T2-weighted MRI was evaluated by two neuroradiologists and divided into four grades by mutual agreement. Initial MRI of all three cases showed a slightly high signal of the bilateral striatum, and the conspicuity of the high signal became more prominent as the disease progressed. In each case the pathological change of striatum and globus pallidus was compared with the high signal on the last MR image. (orig.)

  7. High signal of the striatum in sporadic Creutzfeldt-Jakob disease: sequential change on T2-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Uemura, A.; O' uchi, T.; Sakamoto, T.; Yashiro, N. [Department of Radiology, Kameda Medical Center, Kamogawa, Chiba (Japan)

    2002-04-01

    The object of this study is to describe the sequential change of high signal of the striatum on T2-weighted MRI in sporadic Creutzfeldt-Jakob disease (CJD). Three cases of autopsy-proven sporadic CJD and a total of 18 serial MR images are included in this study. The degree of high signal of the striatum on T2-weighted MRI was evaluated by two neuroradiologists and divided into four grades by mutual agreement. Initial MRI of all three cases showed a slightly high signal of the bilateral striatum, and the conspicuity of the high signal became more prominent as the disease progressed. In each case the pathological change of striatum and globus pallidus was compared with the high signal on the last MR image. (orig.)

  8. Myocardial T1 and T2 mapping: Techniques and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Pan Ki; Hong, Yoo Jin; Im, Dong Jin [Dept. of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); and others

    2017-01-15

    Cardiac magnetic resonance (CMR) imaging is widely used in various medical fields related to cardiovascular diseases. Rapid technological innovations in magnetic resonance imaging in recent times have resulted in the development of new techniques for CMR imaging. T1 and T2 image mapping sequences enable the direct quantification of T1, T2, and extracellular volume fraction (ECV) values of the myocardium, leading to the progressive integration of these sequences into routine CMR settings. Currently, T1, T2, and ECV values are being recognized as not only robust biomarkers for diagnosis of cardiomyopathies, but also predictive factors for treatment monitoring and prognosis. In this study, we have reviewed various T1 and T2 mapping sequence techniques and their clinical applications.

  9. Discrimination of benign and malignant lymph nodes at 7.0T compared to 1.5T magnetic resonance imaging using ultrasmall particles of iron oxide: a feasibility preclinical study.

    Science.gov (United States)

    Kinner, Sonja; Maderwald, Stefan; Albert, Juliane; Parohl, Nina; Corot, Claire; Robert, Philippe; Baba, Hideo A; Barkhausen, Jörg

    2013-12-01

    To investigate the feasibility and performance of 7T magnetic resonance imaging compared to 1.5T imaging to discriminate benign (normal and inflammatory changed) from tumor-bearing lymph nodes in rabbits using ultrasmall particles of iron oxide (USPIO)-based contrast agents. Six New Zealand White rabbits were inoculated with either complete Freund's adjuvant cell suspension (n = 3) to induce reactively enlarged lymph nodes or with VX2 tumor cells to produce metastatic lymph nodes (n = 3). Image acquisition was performed before and 24 hours after bolus injection of an USPIO contrast agent at 1.5T and afterward at 7T using T1-weighted and T2*-weighted sequences. Sensitivities, specificities, and negative and positive predictive values for the detection of lymph node metastases were calculated for both field strengths with histopathology serving as reference standard. Sizes of lymph nodes with no, inflammatory, and malignant changes were compared using a Mann-Whitney U-test. All 24 lymph nodes were detected at 1.5T as well as at 7T. At 1.5T, sensitivity amounted to 0.67, while specificity reached a value of 1. At the higher field strength (7T), imaging was able to reach sensitivity and specificity values of 1. No statistical differences were detected concerning lymph node sizes. Magnetic resonance lymphography with USPIO contrast agents allows for differentiation of normal and reactively enlarged lymph nodes compared to metastatic nodes. First experiments at 7T show promising results compared to 1.5T, which have to be evaluated in further trials. Copyright © 2013. Published by Elsevier Inc.

  10. Comparison of 7T and 3T MRI in patients with moyamoya disease.

    Science.gov (United States)

    Oh, Byeong Ho; Moon, Hyeong Cheol; Baek, Hyeon Man; Lee, Youn Joo; Kim, Sang Woo; Jeon, Young Jai; Lee, Gun Seok; Kim, Hong Rae; Choi, Jai Ho; Min, Kyung Soo; Lee, Mou Seop; Kim, Young Gyu; Kim, Dong Ho; Kim, Won Seop; Park, Young Seok

    2017-04-01

    Magnetic resonance imaging and magnetic resonance angiography (MRI/MRA) are widely used for evaluating the moyamoya disease (MMD). This study compared the diagnostic accuracy of 7Tesla (T) and 3T MRI/MRA in MMD. In this case control study, 12 patients [median age: 34years; range (10-66years)] with MMD and 12 healthy controls [median age: 25years; range (22-59years)] underwent both 7T and 3T MRI/MRA. To evaluate the accuracy of MRI/MRA in MMD, five criteria were compared between imaging systems of 7T and 3T: Suzuki grading system, internal carotid artery (ICA) diameter, ivy sign, flow void of the basal ganglia on T2-weighted images, and high signal intensity areas of the basal ganglia on time-of-flight (TOF) source images. No difference was observed between 7T and 3T MRI/MRA in Suzuki stage, ICA diameter, and ivy sign score; while, 7T MRI/MRA showed a higher detection rate in the flow void on T2-weighted images and TOF source images (p<0.001). Receiver operating characteristic curves of both T2 and TOF criteria showed that 7T MRI/MRA had higher sensitivity and specificity than 3T MRI/MRA. Our findings indicate that 7T MRI/MRA is superior to 3T MRI/MRA for the diagnosis of MMD in point of detecting the flow void in basal ganglia by T2-weighted and TOF images. Copyright © 2016. Published by Elsevier Inc.

  11. SU-E-P-33: Critical Role of T2-Weighted Imaging Combined with Diffusion-Weighted Imaging of MRI in Diagnosis of Loco-Regional Recurrent Esophageal Cancer After Radical Surgery

    Energy Technology Data Exchange (ETDEWEB)

    Deng, G; Qiao, L [Department of Oncology, Shandong University School of Medicine, Jinan, Shandong (China); Liang, N; Xie, J; Zhang, J [Department of Radiation Oncology, Qianfoshan Hospital Affiliated to Shandon, Jinan, Shandong (China); Luo, H; Zhang, J [Division of Oncology, Department of Graduate, Weifang Medical College, Weifang, Shandong (China)

    2015-06-15

    Purpose: We perform this study to investigate the diagnostic efficacy of T2-weighted MRI (T2WI) and diffusion-weighted MRI (DWI) in confirming local relapses of esophageal cancer in patients highly suspected of recurrence after eradicating surgery. Methods: Forty-two postoperative esophageal cancer patients with clinical suspicions of cancer recurrence underwent 3.0T MRI applying axial, coronal, sagittal T2WI and axial DWI sequences. Two experienced radiologists (R1 and R2) both used two methods (T2WI, T2WI+DWI) to observe the images, and graded the patients ranging from 1 to 5 to represent severity of the disease based on visual signal intensity (patients equal to or more than grade 3 was confirmed as recurrent disease) Results: 27/42patients were verified of recurrent disease by pathologic findings and/or imaging findings during follow-up. The sensitivity, specificity and accuracy of R1 applying T2WI+DWI are 96%, 87% and 93% versus 81%, 80% and 77% on T2WI, these figures by R2 were 96%, 93% and 95% versus 89%, 93% and 90%. The receiver operating curve (ROC) analyses suggest that both of the two readers can obtain better accuracy when adding DWI to T2WI compared with T2WI alone. Kappa test between R1 and R2 indicates excellent inter-observer agreement on T2WI+DWI. Conclusion: Standard T2WI in combination DWI can achieve better accuracy than T2WI alone in diagnosing local recurrence of esophageal cancer, and improve consistency between different readers.

  12. Comparative study of fast T 2-weighted images using respiratory triggered, breath-hold, fat suppression and phased array multi coil for liver evaluation by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Abbehusen, Cristiane L.; D'Ippolito, Giuseppe; Palacio, Glaucia A.S.; Szejnfeld, Jacob

    2003-01-01

    The objective of this study was to compare both qualitatively and quantitatively six T 2-weighted turbo spin-echo sequences varying the respiratory compensation technique, associating or not fat tissue suppression and using different types of coils. We performed a prospective study of 71 consecutive patients that were submitted to MRI of the liver using a 1.5 T magnet. The six following pulse sequences were used: fat-suppressed respiratory triggered with conventional body coil; breath-hold fat-suppressed with conventional body coil; non-suppressed respiratory triggered with conventional body coil; breath-hold non fat-suppressed with conventional body coil; fat-suppressed respiratory triggered with phased-array multi coil; breath-hold fat-suppressed with phased-array multi coil. Images were analyzed quantitatively by measuring the signal-to-noise ratios and qualitatively by evaluating the sharpness of hepatic contours, visibility of intrahepatic vessels and other segmental landmarks, and the presence of artifacts. Results: the qualitative analysis showed that the mean values obtained with the six sequences were 7.8, 4.6, 7.9, 5.2, 6.7 and 4.6 respectively. The respiratory-triggered sequences were better than the breath-hold sequences in both qualitative and quantitative analysis (p < 0.001). No significant differences in the values of signal-to-noise ratios and in overall image quality were found between the sequences with and without fat suppression (p . 0.05). The sequences using the body coil were similar in terms of image quality (p . 0.05) and better regarding signal-to-noise ratios than those obtained with the phased=array multi coil (p ,0.001). Our qualitative and quantitative results suggest that the best MRI sequences for the valuation of the liver are the sequences with respiratory triggering using a conventional body coil, with or without fat suppression. (author)

  13. Texture analysis of ultrahigh field T2*-weighted MR images of the brain: application to Huntington's disease.

    Science.gov (United States)

    Doan, Nhat Trung; van den Bogaard, Simon J A; Dumas, Eve M; Webb, Andrew G; van Buchem, Mark A; Roos, Raymund A C; van der Grond, Jeroen; Reiber, Johan H C; Milles, Julien

    2014-03-01

    To develop a framework for quantitative detection of between-group textural differences in ultrahigh field T2*-weighted MR images of the brain. MR images were acquired using a three-dimensional (3D) T2*-weighted gradient echo sequence on a 7 Tesla MRI system. The phase images were high-pass filtered to remove phase wraps. Thirteen textural features were computed for both the magnitude and phase images of a region of interest based on 3D Gray-Level Co-occurrence Matrix, and subsequently evaluated to detect between-group differences using a Mann-Whitney U-test. We applied the framework to study textural differences in subcortical structures between premanifest Huntington's disease (HD), manifest HD patients, and controls. In premanifest HD, four phase-based features showed a difference in the caudate nucleus. In manifest HD, 7 magnitude-based features showed a difference in the pallidum, 6 phase-based features in the caudate nucleus, and 10 phase-based features in the putamen. After multiple comparison correction, significant differences were shown in the putamen in manifest HD by two phase-based features (both adjusted P values=0.04). This study provides the first evidence of textural heterogeneity of subcortical structures in HD. Texture analysis of ultrahigh field T2*-weighted MR images can be useful for noninvasive monitoring of neurodegenerative diseases. Copyright © 2013 Wiley Periodicals, Inc.

  14. Effects of aging on T1, T∗2, and QSM MRI values in the subcortex

    NARCIS (Netherlands)

    Keuken, M.C.; Bazin, P.-L.; Backhouse, K.; Beekhuizen, S.; Himmer, L.; Kandola, A.; Lafeber, J.J.; Prochazkova, L.; Trutti, A.; Schäfer, A.; Turner, R.; Forstmann, B.U.

    The aging brain undergoes several anatomical changes that can be measured with Magnetic Resonance Imaging (MRI). Early studies using lower field strengths have assessed changes in tissue properties mainly qualitatively, using T1 - or T∗2 - weighted images to provide image contrast. With the

  15. Magnetic resonance imaging of muscle tears

    International Nuclear Information System (INIS)

    De Smet, A.A.; Fisher, D.R.; Heiner, J.P.; Keene, J.S.

    1990-01-01

    Magnetic resonance scans were obtained on 17 patients with acute, subacute, or chronic muscle tears. These patients presented with complaints of persistent pain or a palpable mass. Magnetic resonance findings were characterized according to alterations in muscle shape and the presence of abnormal high signal within the injured muscle. These areas of high signal were noted on both T1-weighted and T2-weighted scans and were presumed to represent areas of intramuscular hemorrhage. (orig.)

  16. Diferenciação entre cisto simples e hemangioma hepático utilizando seqüência de ressonância magnética ponderada em T2 com técnica gradiente-eco (B-FFE Differentiation between simple cyst and hepatic hemangioma utilizing T2-weighted magnetic resonance imaging with gradient-echo (b-FFE technique

    Directory of Open Access Journals (Sweden)

    Carolina Valente Burim

    2008-12-01

    Full Text Available OBJETIVO: Estabelecer o valor das seqüências ponderadas em T2 para diferenciar cistos simples de hemangiomas hepáticos. MATERIAIS E MÉTODOS: Estudo prospectivo, observacional, transversal e duplo-cego em 52 pacientes com 91 lesões hepáticas (34 cistos simples e 57 hemangiomas submetidos a ressonância magnética de abdome. A análise conjunta de todas as seqüências realizadas foi considerada o padrão-ouro. Dois observadores independentes avaliaram, subjetivamente, as seqüências TSE com TE longo e B-FFE, procurando diferenciar cistos de hemangiomas. Foram calculadas a eficácia das seqüências e a concordância interobservador e intra-observador por meio do teste kappa (κ (p OBJECTIVE: To establish the role of MRI T2-weighted sequences in the differentiation between simple cysts and hepatic hemangiomas. MATERIALS AND METHODS: A double-blinded, prospective, observational, cross-sectional study evaluated 52 patients with 91 hepatic lesions (34 simple cysts and 57 hemangiomas submitted to abdominal magnetic resonance imaging. The combined analysis of all sequences was considered as the golden-standard. TSE sequences with long echo trains and b-FFE sequences were subjectively analyzed by two independent observers for differentiating cysts from hemangiomas. The kappa test (κ was utilized in the analysis of the methods accuracy and inter- and intra-observer agreement (p < 0.05*. RESULTS: Cysts and hemangiomas dimensions ranged respectively between 0.5 and 6.5 cm (mean = 1.89 cm, and 0.8 and 11 cm (mean = 2.62 cm. The analysis of the sequences with long-TE and the golden-standard demonstrated a non-statistically significant agreement (κ: 0.00-0.10. The agreement between the evaluation of the b-FFE sequence and the golden-standard ranged from substantial (κ: 0.62-0.71 to almost perfect (κ: 0.86 for both observers. The inter- and intra-observer agreement for the b-FFE sequence ranged from substantial (κ: 0.62-0.70 to almost perfect (κ

  17. The role of T2*-weighted gradient echo in the diagnosis of tumefactive intrahepatic extramedullary hematopoiesis in myelodysplastic syndrome and diffuse hepatic iron overload: a case report and review of the literature.

    Science.gov (United States)

    Belay, Abel A; Bellizzi, Andrew M; Stolpen, Alan H

    2018-01-15

    Extramedullary hematopoiesis is the proliferation of hematopoietic cells outside bone marrow secondary to marrow hematopoiesis failure. Extramedullary hematopoiesis rarely presents as a mass-forming hepatic lesion; in this case, imaging-based differentiation from primary and metastatic hepatic neoplasms is difficult, often leading to biopsy for definitive diagnosis. We report a case of tumefactive hepatic extramedullary hematopoiesis in the setting of myelodysplastic syndrome with concurrent hepatic iron overload, and the role of T2*-weighted gradient-echo magnetic resonance imaging in differentiating extramedullary hematopoiesis from primary and metastatic hepatic lesions. To the best of our knowledge, T2*-weighted gradient-echo evaluation of extramedullary hematopoiesis in the setting of diffuse hepatic hemochromatosis has not been previously described. A 52-year-old white man with myelodysplastic syndrome and marrow fibrosis was found to have a 4 cm hepatic lesion on ultrasound during workup for bone marrow transplantation. Magnetic resonance imaging revealed diffuse hepatic iron overload and non-visualization of the lesion on T2* gradient-echo sequence suggesting the presence of iron deposition within the lesion similar to that in background hepatic parenchyma. Subsequent ultrasound-guided biopsy of the lesion revealed extramedullary hematopoiesis. Six months later, while still being evaluated for bone marrow transplant, our patient was found to have poor pulmonary function tests. Follow-up computed tomography angiogram showed a mass within his right main pulmonary artery. Bronchoscopic biopsy of this mass once again revealed extramedullary hematopoiesis. He received radiation therapy to his chest. However, 2 weeks later, he developed mediastinal hematoma and died shortly afterward, secondary to respiratory arrest. Mass-forming extramedullary hematopoiesis is rare; however, our report emphasizes that it needs to be considered in the initial differential

  18. Molecular Imaging of Tumors Using a Quantitative T1 Mapping Technique via Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Kelsey Herrmann

    2015-07-01

    Full Text Available Magnetic resonance imaging (MRI of glioblastoma multiforme (GBM with molecular imaging agents would allow for the specific localization of brain tumors. Prior studies using T1-weighted MR imaging demonstrated that the SBK2-Tris-(Gd-DOTA3 molecular imaging agent labeled heterotopic xenograft models of brain tumors more intensely than non-specific contrast agents using conventional T1-weighted imaging techniques. In this study, we used a dynamic quantitative T1 mapping strategy to more objectively compare intra-tumoral retention of the SBK2-Tris-(Gd-DOTA3 agent over time in comparison to non-targeted control agents. Our results demonstrate that the targeted SBK2-Tris-(Gd-DOTA3 agent, a scrambled-Tris-(Gd-DOTA3 control agent, and the non-specific clinical contrast agent Optimark™ all enhanced flank tumors of human glioma cells with similar maximal changes on T1 mapping. However, the retention of the agents differs. The non-specific agents show significant recovery within 20 min by an increase in T1 while the specific agent SBK2-Tris-(Gd-DOTA3 is retained in the tumors and shows little recovery over 60 min. The retention effect is demonstrated by percent change in T1 values and slope calculations as well as by calculations of gadolinium concentration in tumor compared to muscle. Quantitative T1 mapping demonstrates the superior binding and retention in tumors of the SBK2-Tris-(Gd-DOTA3 agent over time compared to the non-specific contrast agent currently in clinical use.

  19. High-T/sub c/ superconductor and its use in superconducting magnets

    International Nuclear Information System (INIS)

    Green, M.A.

    1988-02-01

    Many of the proposed uses for the high-T/sub c/ superconductor involve the creation of a magnetic field using superconducting coils. This report will assess what is known about the high-T/sub c/ superconductors and take a realistic look at their potential use in various kinds of superconducting magnets. Based on what is known about the high-T/sub c/ superconductors, one can make a ''wish list'' of things that will make such materials useful for magnets. Then, the following question is asked. If one had a high-T/sub c/ superconductor with the same properties as modern niobium-titanium superconductor, how would the superconductor work in a magnet environment? Finally, this report will show the potential impact of the ideal high-T/sub c/ superconductor on: 1) accelerator dipole and quadrupole magnets, 2) superconducting magnets for use in space, and 3) superconducting solenoids for magnetic resonance imaging. 78 refs., 11 tabs

  20. Evaluation of multimodal segmentation based on 3D T1-, T2- and FLAIR-weighted images - the difficulty of choosing.

    Science.gov (United States)

    Lindig, Tobias; Kotikalapudi, Raviteja; Schweikardt, Daniel; Martin, Pascal; Bender, Friedemann; Klose, Uwe; Ernemann, Ulrike; Focke, Niels K; Bender, Benjamin

    2018-04-15

    Voxel-based morphometry is still mainly based on T1-weighted MRI scans. Misclassification of vessels and dura mater as gray matter has been previously reported. Goal of the present work was to evaluate the effect of multimodal segmentation methods available in SPM12, and their influence on identification of age related atrophy and lesion detection in epilepsy patients. 3D T1-, T2- and FLAIR-images of 77 healthy adults (mean age 35.8 years, 19-66 years, 45 females), 7 patients with malformation of cortical development (MCD) (mean age 28.1 years,19-40 years, 3 females), and 5 patients with left hippocampal sclerosis (LHS) (mean age 49.0 years, 25-67 years, 3 females) from a 3T scanner were evaluated. Segmentation based on T1-only, T1+T2, T1+FLAIR, T2+FLAIR, and T1+T2+FLAIR were compared in the healthy subjects. Clinical VBM results based on the different segmentation approaches for MCD and for LHS were compared. T1-only segmentation overestimated total intracranial volume by about 80ml compared to the other segmentation methods. This was due to misclassification of dura mater and vessels as GM and CSF. Significant differences were found for several anatomical regions: the occipital lobe, the basal ganglia/thalamus, the pre- and postcentral gyrus, the cerebellum, and the brainstem. None of the segmentation methods yielded completely satisfying results for the basal ganglia/thalamus and the brainstem. The best correlation with age could be found for the multimodal T1+T2+FLAIR segmentation. Highest T-scores for identification of LHS were found for T1+T2 segmentation, while highest T-scores for MCD were dependent on lesion and anatomical location. Multimodal segmentation is superior to T1-only segmentation and reduces the misclassification of dura mater and vessels as GM and CSF. Depending on the anatomical region and the pathology of interest (atrophy, lesion detection, etc.), different combinations of T1, T2 and FLAIR yield optimal results. Copyright © 2017 Elsevier

  1. Dynamic T2-mapping during magnetic resonance guided high intensity focused ultrasound ablation of bone marrow

    International Nuclear Information System (INIS)

    Waspe, Adam C.; Looi, Thomas; Mougenot, Charles; Amaral, Joao; Temple, Michael; Sivaloganathan, Siv; Drake, James M.

    2012-01-01

    Focal bone tumor treatments include amputation, limb-sparing surgical excision with bone reconstruction, and high-dose external-beam radiation therapy. Magnetic resonance guided high intensity focused ultrasound (MR-HIFU) is an effective non-invasive thermotherapy for palliative management of bone metastases pain. MR thermometry (MRT) measures the proton resonance frequency shift (PRFS) of water molecules and produces accurate ( 2 , since T 2 increases linearly in fat during heating. T 2 -mapping using dual echo times during a dynamic turbo spin-echo pulse sequence enabled rapid measurement of T 2 . Calibration of T 2 -based thermal maps involved heating the marrow in a bovine femur and simultaneously measuring T 2 and temperature with a thermocouple. A positive T 2 temperature dependence in bone marrow of 20 ms/°C was observed. Dynamic T 2 -mapping should enable accurate temperature monitoring during MR-HIFU treatment of bone marrow and shows promise for improving the safety and reducing the invasiveness of pediatric bone tumor treatments.

  2. Weak ferrimagnetism, compensation point and magnetization reversal in Ni(HCOO)2x2H2O

    International Nuclear Information System (INIS)

    Kageyama, H.; Khomskii, D.I.; Levitin, R.Z.; Vasiliev, A.N.

    2003-01-01

    Nickel (II) format dihydrate Ni(HCOO) 2 x2H 2 O shows peculiar magnetic response at T N =15.5 K. The magnitude of weak magnetic moment increases initially below T N , equals zero at T*=8.5 K and increases again at lowering temperature. The sign of low field magnetization at any given temperature is determined by the sample's magnetic prehistory and the signs are opposite to each other at T N . This behavior suggests that Ni(HCOO) 2 x2H 2 O is a weak ferrimagnet and T* is a compensation point

  3. Optimization image of magnetic resonance imaging (MRI) T2 fast spin echo (FSE) with variation echo train length (ETL) on the rupture tendon achilles case

    International Nuclear Information System (INIS)

    Muzamil, Akhmad; Firmansyah, Achmad Haries

    2017-01-01

    The research was done the optimization image of Magnetic Resonance Imaging (MRI) T2 Fast Spin Echo (FSE) with variation Echo Train Length (ETL) on the Rupture Tendon Achilles case. This study aims to find the variations Echo Train Length (ETL) from the results of ankle’s MRI image and find out how the value of Echo Train Length (ETL) works on the MRI ankle to produce optimal image. In this research, the used ETL variations were 12 and 20 with the interval 2 on weighting T2 FSE sagittal. The study obtained the influence of Echo Train Length (ETL) on the quality of ankle MRI image sagittal using T2 FSE weighting and analyzed in 25 images of five patients. The data analysis has done quantitatively with the Region of Interest (ROI) directly on computer MRI image planes which conducted statistical tests Signal to Noise Ratio (SNR) and Contras to Noise Ratio (CNR). The Signal to Noise Ratio (SNR) was the highest finding on fat tissue, while the Contras to Noise Ratio (CNR) on the Tendon-Fat tissue with ETL 12 found in two patients. The statistics test showed the significant SNR value of the 0.007 (p<0.05) of Tendon tissue, 0.364 (p>0.05) of the Fat, 0.912 (p>0.05) of the Fibula, and 0.436 (p>0.05) of the Heel Bone. For the contrast to noise ratio (CNR) of the Tendon-FAT tissue was about 0.041 (p>0.05). The results of the study showed that ETL variation with T2 FSE sagittal weighting had difference at Tendon tissue and Tendon-Fat tissue for MRI imaging quality. SNR and CNR were an important aspect on imaging optimization process to give the diagnose information. (paper)

  4. Evaluation of renal oxygenation level changes after water loading using susceptibility-weighted imaging and T2{sup *} mapping

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Jiule; Xing, Wei; Chen, Jie; Pan, Liang; Sun, Jun; Xing, Shi Jun [Dept. of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou (China); Wu, Dong Mei [Shanghai Key Laboratory of Magnetic Resonance Imaging, East China Normal University, Shanghai (China); Dai, Yong Ming [Philips Healthcare, Shanghai (China)

    2015-08-15

    To assess the feasibility of susceptibility-weighted imaging (SWI) while monitoring changes in renal oxygenation level after water loading. Thirty-two volunteers (age, 28.0 ± 2.2 years) were enrolled in this study. SWI and multi-echo gradient echo sequence-based T2{sup *} mapping were used to cover the kidney before and after water loading. Cortical and medullary parameters were measured using small regions of interest, and their relative changes due to water loading were calculated based on baseline and post-water loading data. An intraclass correlation coefficient analysis was used to assess inter-observer reliability of each parameter. A receiver operating characteristic curve analysis was conducted to compare the performance of the two methods for detecting renal oxygenation changes due to water loading. Both medullary phase and medullary T2{sup *} values increased after water loading (p < 0.001), although poor correlations were found between the phase changes and the T2{sup *} changes (p > 0.05). Interobserver reliability was excellent for the T2{sup *} values, good for SWI cortical phase values, and moderate for the SWI medullary phase values. The area under receiver operating characteristic curve of the SWI medullary phase values was 0.85 and was not different from the medullary T2{sup *} value (0.84). Susceptibility-weighted imaging enabled monitoring changes in the oxygenation level in the medulla after water loading, and may allow comparable feasibility to detect renal oxygenation level changes due to water loading compared with that of T2{sup *} mapping.

  5. Added diagnostic value of T2-weighted MR imaging to gadolinium-enhanced three-dimensional dynamic MR imaging for the detection of small hepatocellular carcinomas

    International Nuclear Information System (INIS)

    Kim, Young Kon; Lee, Young Hwan; Kim, Chong Soo; Han, Young Min

    2008-01-01

    Purpose: To assess the added value of T2-weighted MRI to gadolinium-enhanced dynamic MRI for detection of HCCs. Materials and methods: Two readers retrospectively analyzed MRIs of 115 patients with 131 HCCs (size; 0.6-2.0 cm) that had been diagnosed by histology (n = 41) or imaging findings (n = 90). Two separate blind image analyses of the gadolinium set and the combined T2-weighted imaging and gadolinium sets were performed. Diagnostic accuracy was evaluated using the alternative-free response receiver operating characteristic method with four-point scale. Sensitivity and positive predictive value were also calculated. Results: For both observers, the Az values and sensitivities with the combined T2-weighed imaging and gadolinium set (mean Az 0.806, sensitivity 84.7) were significantly higher than those with the gadolinium set (mean Az 0.660, sensitivity 59.9) (p < 0.05). The addition of T2-weighted imaging led to a change in diagnosis for 27 lesions by both observers, which at gadolinium set were assigned a confidence level of 1 or 2 but at additional reading of T2-weighted imaging were assigned a confidence level of 3 or 4. For the positive predictive values, each image set showed a similar value for each observer. Conclusion: The addition of T2-weighted imaging to gadolinium-enhanced 3D dynamic imaging could be helpful in the detection of HCC by increasing reader confidence for HCCs with equivocal findings on gadolinium-enhanced MRIs

  6. In-plane optical spectral weight redistribution in the optimally doped Ba0.6 K0.4Fe2As2 superconductor

    International Nuclear Information System (INIS)

    Xu Bing; Dai Yao-Min; Xiao Hong; Qiu Xiang-Gang; Lobo, R. P. S. M.

    2014-01-01

    We performed detailed temperature-dependent optical measurements on optimally doped Ba 0.6 K 0.4 Fe 2 As 2 single crystal. We examine the changes of the in-plane optical conductivity spectral weight in the normal state and the evolution of the superconducting condensate in the superconducting state. In the normal state, the low-frequency spectral weight shows a metallic response with an arctan (T) dependence, indicating a T-linear scattering rate behavior for the carriers. A high energy spectral weight transfer associated with the Hund's coupling occurs from the low frequencies below 4000 cm −1 ∼ 5000 cm −1 to higher frequencies up to at least 10 cm −1 . Its temperature dependence analysis suggests that the Hund's coupling strength is continuously enhanced as the temperature is reduced. In the superconducting state, the FGT sum rule is conserved according to the spectral weight estimation within the conduction bands, only about 40% of the conduction bands participates in the superconducting condensate indicating that Ba 0.6 K 0.4 Fe 2 As 2 is in dirty limit. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  7. Unenhanced breast MRI (STIR, T2-weighted TSE, DWIBS): An accurate and alternative strategy for detecting and differentiating breast lesions.

    Science.gov (United States)

    Telegrafo, Michele; Rella, Leonarda; Stabile Ianora, Amato Antonio; Angelelli, Giuseppe; Moschetta, Marco

    2015-10-01

    To assess the role of STIR, T2-weighted TSE and DWIBS sequences for detecting and characterizing breast lesions and to compare unenhanced (UE)-MRI results with contrast-enhanced (CE)-MRI and histological findings, having the latter as the reference standard. Two hundred eighty consecutive patients (age range, 27-73 years; mean age±standard deviation (SD), 48.8±9.8years) underwent MR examination with a diagnostic protocol including STIR, T2-weighted TSE, THRIVE and DWIBS sequences. Two radiologists blinded to both dynamic sequences and histological findings evaluated in consensus STIR, T2-weighted TSE and DWIBS sequences and after two weeks CE-MRI images searching for breast lesions. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy for UE-MRI and CE-MRI were calculated. UE-MRI results were also compared with CE- MRI. UE-MRI sequences obtained sensitivity, specificity, diagnostic accuracy, PPV and NPV values of 94%, 79%, 86%, 79% and 94%, respectively. CE-MRI sequences obtained sensitivity, specificity, diagnostic accuracy, PPV and NPV values of 98%, 83%, 90%, 84% and 98%, respectively. No statistically significant difference between UE-MRI and CE-MRI was found. Breast UE-MRI could represent an accurate diagnostic tool and a valid alternative to CE-MRI for evaluating breast lesions. STIR and DWIBS sequences allow to detect breast lesions while T2-weighted TSE sequences and ADC values could be useful for lesion characterization. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Comparison between T2-weighted MR and contrast-enhanced MR cholangiography in the evaluation of biliary anatomy in liver transplant donor candidates

    International Nuclear Information System (INIS)

    Wang Hong; Mu Xuetao; Wu Chunnan; Dong Yuru; Dong Yue; Zhang Huiqing; Zang Yunjin

    2008-01-01

    Objective: To compare conventional T 2 -weighted MR cholangiography (T 2 WI-MRC) with gadobenate dimeglumine enhanced T 1 -weighted MR cholangiography(CE-MRC) for evalution of biliary anatomy in liver transplant donor candidates. Methods: Thirty-two healthy liver transplant donor candidates were examined with two MR cholangiographic methods. For T 2 WI-MRC, a three-dimensional turbo spin-echo sequence and oblique coronal heavily T 2 -weighted thick-slab turbo spin-echo imaging sequence were performed. For CE-MRC, three-dimensional fat-suppressed spoiled gradient-echo sequences were performed, with a time delay of 60 minutes following the administration of gadobenate dimeglumine. To compare the depiction of biliary duct anatomy and the artifact caused by intestinal liquid and breathing between the two methods. Intraoperative cholangiography was the reference-standard examination. Results: The both methods depicted the biliary anatomy correctly in all 9 cases. The both methods showed the third branches of intrahepatic biliary duct clearly. T 2 WI-MRC showed interhepatic biliary duct before the third branches in 28 cases (87.5%), CE-MRC showed the same finding in 14 eases (43.8%). T 2 WI-MRC showed common bile ducts intermitantly in 2 cases, which were normal in CE-MRC and intraoperative cholangiography. Intestinal liquid affected the image quality of biliary duct in 6 cases (18.8%) performed with T 2 WI-MRC, but none with CE-MRC. The artifacts caused by breathing were not obvious in the either method. Conclusion: T 2 WI-MRC and CE-MRC both can be used to evaluate biliary anatomy of liver transplant donor candidates, but CE-MRC appears to be more accurate than T 2 WI-MRC. (authors)

  9. Diffusion-weighted magnetic resonance imaging: a potential non-invasive marker of tumour aggressiveness in localized prostate cancer

    International Nuclear Information System (INIS)

    Souza, N.M. de; Riches, S.F.; Van As, N.J.; Morgan, V.A.; Ashley, S.A.; Fisher, C.; Payne, G.S.; Parker, C.

    2008-01-01

    Aim: To evaluate diffusion-weighted magnetic resonance imaging (DW-MRI) as a marker for disease aggressiveness by comparing tumour apparent diffusion coefficients (ADCs) between patients with low- versus higher-risk localized prostate cancer. Method: Forty-four consecutive patients classified as low- [n = 26, stageT1/T2a, Gleason score ≤ 6, prostate-specific antigen (PSA) 10 (group 2)] risk, who subsequently were monitored with active surveillance or started neoadjuvant hormone and radiotherapy, respectively, underwent endorectal MRI. T2-weighted (T2W) and DW images (5 b values, 0-800 s/mm 2 ) were acquired and isotropic ADC maps generated. Regions of interest (ROIs) on T2W axial images [around whole prostate, central gland (CG), and tumour] were transferred to ADC maps. Tumour, CG, and peripheral zone (PZ = whole prostate minus CG and tumour) ADCs (fast component from b = 0-100 s/mm 2 , slow component from b = 100-800 s/mm 2 ) were compared. Results: T2W-defined tumour volume medians, and quartiles were 1.2 cm 3 , 0.7 and 3.3 cm 3 (group 1); and 6 cm 3 , 1.3 and 16.5 cm 3 (group 2). There were significant differences in both ADC fast (1778 ± 264 x 10 -6 versus 1583 ± 283 x 10 -6 mm 2 /s, p = 0.03) and ADC slow (1379 ± 321 x 10 -6 versus 1196 ± 158 x 10 -6 mm 2 /s, p = 0.001) between groups. Tumour volume (p = 0.002) and ADC slow (p = 0.005) were significant differentiators of risk group. Conclusion: Significant differences in tumour ADCs exist between patients with low-risk, and those with higher-risk localized prostate cancer. DW-MRI merits further study with respect to clinical outcomes

  10. Acute vertebral fracture: differentiation of malignant and benign causes by diffusion weighted magnetic resonance imaging

    International Nuclear Information System (INIS)

    Mubarak, F.; Akhtar, W.

    2011-01-01

    Objective: To evaluate the sensitivity, specificity and accuracy of diffusion weighted (DWI) magnetic resonance imaging (MRI) in the diagnosis and differentiation between benign (osteoporotic/infectious) and malignant vertebral compression fractures in comparison with histology findings and clinical follow up. Methods: The study was conducted at the Radiology Department, Aga Khan University Hospital (AKUH) Karachi. It was a one year cross-sectional study from 01/01/2009 to 01/01/2010. Forty patients with sixty three vertebral compression fractures were included. Diffusion-weighted sequences and apparent diffusion coefficient (ADC) images on a 1.5 T MR scanner were obtained in all patients to identify the vertebral compression fracture along with benign and malignant causes. Imaging findings were compared with histopathologic results and clinical follow-up. Results: Diffusion-weighted MR imaging found to have, 92% sensitivity, 90% specificity and accuracy of 85% in differentiation of benign and malignant vertebral compression fracture while PPV and NPV were 78 % and 90% respectively. Conclusion: Diffusion weighted magnetic resonance imaging offers a safe, accurate and non invasive modality to differentiate between the benign and malignant vertebral compression fracture. (author)

  11. Application of three-dimensional fast spin-echo T2-weighted image in lesions of the inner ear

    International Nuclear Information System (INIS)

    Xian Junfang; Wang Zhenchang; Yan Fei; Niu Yantao; Zhu Ye; Wang Yan; Tian Qichang; Lan Baosen

    1999-01-01

    Objective: To investigate the advantage of three-dimensional fast spin-echo T 2 -weighted image (3D FSE T 2 WI) in depicting normal structures and lesions of the inner ear. Methods: 3D FSE T 2 WI and 2D FSE T 2 WI were performed in 10 healthy volunteers and 20 cases with inner ear diseases. Advantages and disadvantages of the two techniques were compared. CT was performed in 6 cases with enlarged endo-lymphatic sac and 1 cases of Mondini malformation. Results: 3D FSE T 2 WI enabled visualization of detailed anatomic structures. Enlarged endo-lymphatic sacs were clearly revealed in 9 cases on 16 sides by 3D FSE T 2 WI, while only a part but not the whole of the enlarged endo-lymphatic sac could be shown on 2D FSE T 2 WI. In 6 cases, 3D FSE T 2 WI displayed enlarged endo-lymphatic sac on 11 sides and normal on 1 side; however, CT revealed enlarged vestibular aqueduct on all 12 sides. One case with small acoustic neuroma (only 4 mm in diameter) was clearly demonstrated on 3D FSE T 2 WI but not well shown on 2D FSE T 2 WI. One case with cochlear Mondini malformation associated with dysplasia of vestibule and semicircular canals was displayed more clearly on 3D FSE T 2 WI than on 2D FSE T 2 WI. Conclusions: 3D FSE T 2 WI can clearly display normal structures and lesions of the inner ear

  12. Quantitative T1 and T2* carotid atherosclerotic plaque imaging using a three-dimensional multi-echo phase-sensitive inversion recovery sequence: a feasibility study.

    Science.gov (United States)

    Fujiwara, Yasuhiro; Maruyama, Hirotoshi; Toyomaru, Kanako; Nishizaka, Yuri; Fukamatsu, Masahiro

    2018-06-01

    Magnetic resonance imaging (MRI) is widely used to detect carotid atherosclerotic plaques. Although it is important to evaluate vulnerable carotid plaques containing lipids and intra-plaque hemorrhages (IPHs) using T 1 -weighted images, the image contrast changes depending on the imaging settings. Moreover, to distinguish between a thrombus and a hemorrhage, it is useful to evaluate the iron content of the plaque using both T 1 -weighted and T 2 *-weighted images. Therefore, a quantitative evaluation of carotid atherosclerotic plaques using T 1 and T 2 * values may be necessary for the accurate evaluation of plaque components. The purpose of this study was to determine whether the multi-echo phase-sensitive inversion recovery (mPSIR) sequence can improve T 1 contrast while simultaneously providing accurate T 1 and T 2 * values of an IPH. T 1 and T 2 * values measured using mPSIR were compared to values from conventional methods in phantom and in vivo studies. In the phantom study, the T 1 and T 2 * values estimated using mPSIR were linearly correlated with those of conventional methods. In the in vivo study, mPSIR demonstrated higher T 1 contrast between the IPH phantom and sternocleidomastoid muscle than the conventional method. Moreover, the T 1 and T 2 * values of the blood vessel wall and sternocleidomastoid muscle estimated using mPSIR were correlated with values measured by conventional methods and with values reported previously. The mPSIR sequence improved T 1 contrast while simultaneously providing accurate T 1 and T 2 * values of the neck region. Although further study is required to evaluate the clinical utility, mPSIR may improve carotid atherosclerotic plaque detection and provide detailed information about plaque components.

  13. Extrahepatic portal vein obstruction with parkinsonism and symmetric hyperintense basal ganglia on T1 weighted MRI

    Directory of Open Access Journals (Sweden)

    Jayalakshmi Sita

    2006-01-01

    Full Text Available Abnormal high signal in the globus pallidus on T1 weighted magnetic resonance imaging (MRI of the brain has been well described in patients with chronic liver disease. It may be related to liver dysfunction or portal-systemic shunting. We report a case of extra hepatic portal vein obstruction with portal hypertension and esophageal varices that presented with extra pyramidal features. T1 weighted MRI brain scans showed increased symmetrical signal intensities in the basal ganglia. Normal hepatic function in this patient emphasizes the role of portal- systemic communications in the development of these hyperintensities, which may be due to deposition of paramagnetic substances like manganese in the basal ganglia.

  14. Histogram analysis of T2*-based pharmacokinetic imaging in cerebral glioma grading.

    Science.gov (United States)

    Liu, Hua-Shan; Chiang, Shih-Wei; Chung, Hsiao-Wen; Tsai, Ping-Huei; Hsu, Fei-Ting; Cho, Nai-Yu; Wang, Chao-Ying; Chou, Ming-Chung; Chen, Cheng-Yu

    2018-03-01

    To investigate the feasibility of histogram analysis of the T2*-based permeability parameter volume transfer constant (K trans ) for glioma grading and to explore the diagnostic performance of the histogram analysis of K trans and blood plasma volume (v p ). We recruited 31 and 11 patients with high- and low-grade gliomas, respectively. The histogram parameters of K trans and v p , derived from the first-pass pharmacokinetic modeling based on the T2* dynamic susceptibility-weighted contrast-enhanced perfusion-weighted magnetic resonance imaging (T2* DSC-PW-MRI) from the entire tumor volume, were evaluated for differentiating glioma grades. Histogram parameters of K trans and v p showed significant differences between high- and low-grade gliomas and exhibited significant correlations with tumor grades. The mean K trans derived from the T2* DSC-PW-MRI had the highest sensitivity and specificity for differentiating high-grade gliomas from low-grade gliomas compared with other histogram parameters of K trans and v p . Histogram analysis of T2*-based pharmacokinetic imaging is useful for cerebral glioma grading. The histogram parameters of the entire tumor K trans measurement can provide increased accuracy with additional information regarding microvascular permeability changes for identifying high-grade brain tumors. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Performance of T2 Maps in the Detection of Prostate Cancer.

    Science.gov (United States)

    Chatterjee, Aritrick; Devaraj, Ajit; Mathew, Melvy; Szasz, Teodora; Antic, Tatjana; Karczmar, Gregory S; Oto, Aytekin

    2018-05-03

    This study compares the performance of T2 maps in the detection of prostate cancer (PCa) in comparison to T2-weighted (T2W) magnetic resonance images. The prospective study was institutional review board approved. Consenting patients (n = 45) with histologic confirmed PCa underwent preoperative 3-T magnetic resonance imaging with or without endorectal coil. Two radiologists, working independently, marked regions of interests (ROIs) on PCa lesions separately on T2W images and T2 maps. Each ROI was assigned a score of 1-5 based on the confidence in accurately detecting cancer, with 5 being the highest confidence. Subsequently, the histologically confirmed PCa lesions (n = 112) on whole-mount sections were matched with ROIs to calculate sensitivity, positive predictive value (PPV), and radiologist confidence score. Quantitative T2 values of PCa and benign tissue ROIs were measured. Sensitivity and confidence score for PCa detection were similar for T2W images (51%, 4.5 ± 0.8) and T2 maps (52%, 4.5 ± 0.6). However, PPV was significantly higher (P = .001) for T2 maps (88%) compared to T2W (72%) images. The use of endorectal coils nominally improved sensitivity (T2W: 55 vs 47%, T2 map: 54% vs 48%) compared to the use of no endorectal coils, but not the PPV and the confidence score. Quantitative T2 values for PCa (105 ± 28 milliseconds) were significantly (P = 9.3 × 10 -14 ) lower than benign peripheral zone tissue (211 ± 71 milliseconds), with moderate significant correlation with Gleason score (ρ = -0.284). Our study shows that review of T2 maps by radiologists has similar sensitivity but higher PPV compared to T2W images. Additional quantitative information obtained from T2 maps is helpful in differentiating cancer from normal prostate tissue and determining its aggressiveness. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  16. 3 T magnetic resonance diffusion tensor imaging and fibre tracking in cervical myelopathy

    International Nuclear Information System (INIS)

    Xiangshui, M.; Xiangjun, C.; Xiaoming, Z.; Qingshi, Z.; Yi, C.; Chuanqiang, Q.; Xiangxing, M.; Chuanfu, L.; Jinwen, H.

    2010-01-01

    Aim: To analyse the characterization of diffusion tensor imaging (DTI) with 3 T magnetic resonance imaging (MRI) in cervical myelopathy. Methods: A total of 21 healthy controls and 84 patients with cervical myelopathy underwent T2-weighted imaging and DTI. The patients were divided into four groups based on the degree of cord compression and MRI signal intensity of the compressed cord as seen on T2-weighted images. The values of apparent diffusion coefficient (ADC), fractional anisotropy (FA), and eigenvalues (λ i ) were analysed, and fibre tracking (FT) was performed. Results: For healthy controls, the mean values from the DTI of the cervical spinal cord were ADC = 0.784 ± 0.083 x 10 -3 mm 2 /s, FA = 0.721 ± 0.027, λ 1 , λ 2 , and λ 3 = 1.509 ± 0.145 x 10 -3 , 0.416 ± 0.094 x 10 -3 , and 0.411 ± 0.102 x 10 -3 mm 2 /s, respectively. Only values for λ 2 and λ 3 differed significantly between the control and A groups (p 2 and λ 3 of group A were 0.516 ± 0.105 x 10 -3 and 0.525 ± 0.129 x 10 -3 mm 2 /s, respectively. ADC, FA, λ 1 , λ 2 and λ 3 differed significantly between the control and B, C, D groups (p i obtained with DTI could assess subtle structural damage and changes of anisotropy in the cord of cervical myelopathy. Fibre tracking was useful in verifying changes in the compressed cord.

  17. Magnetic resonance imaging in the acute stage of cerebrovascular disease

    International Nuclear Information System (INIS)

    Tanaka, Tokutaro; Sakai, Tsuneo; Fujishima, Ichiro; Yamamoto, Takamichi; Uemura, Kenichi; Teramura, Atsushi.

    1988-01-01

    Thirty patients with acute cerebrovascular disease were evaluated by both computed tomography (CT) and magnetic resonance (MR) imaging. The 17 patients with cerebral infarction (CI) were evaluated within 24 hours and the 13 with intracerebral hemorrhage (ICH) within 6 hours of the onset of symptoms. All ICHs were detected in T2-weighted images and appeared as perifocal, ring-like areas of high signal intensity. T2-weighted images also demonstrated a ruptured aneurysm and an arteriovenous malformation. In T1-weighted images, all ICHs displayed high signal intensity, which paralleled the CT images and is characteristic of MR imaging with an ultra-low magnetic filed. These findings were obtained as early as 90 minutes from the onset of symptoms. In cases of CI, T2-weighted images obtained 3 - 7 hours after onset demonstrated the pathology more clearly than did CT. This study proved MR imaging useful in the evaluation of both ICH and CI in the acute stage. In addition, it was possible to differentiate ICH from CI in the acute stage by T2-weighted images alone. (author)

  18. Detailing the relation between renal T2* and renal tissue pO2 using an integrated approach of parametric magnetic resonance imaging and invasive physiological measurements.

    Science.gov (United States)

    Pohlmann, Andreas; Arakelyan, Karen; Hentschel, Jan; Cantow, Kathleen; Flemming, Bert; Ladwig, Mechthild; Waiczies, Sonia; Seeliger, Erdmann; Niendorf, Thoralf

    2014-08-01

    This study was designed to detail the relation between renal T2* and renal tissue pO2 using an integrated approach that combines parametric magnetic resonance imaging (MRI) and quantitative physiological measurements (MR-PHYSIOL). Experiments were performed in 21 male Wistar rats. In vivo modulation of renal hemodynamics and oxygenation was achieved by brief periods of aortic occlusion, hypoxia, and hyperoxia. Renal perfusion pressure (RPP), renal blood flow (RBF), local cortical and medullary tissue pO2, and blood flux were simultaneously recorded together with T2*, T2 mapping, and magnetic resonance-based kidney size measurements (MR-PHYSIOL). Magnetic resonance imaging was carried out on a 9.4-T small-animal magnetic resonance system. Relative changes in the invasive quantitative parameters were correlated with relative changes in the parameters derived from MRI using Spearman analysis and Pearson analysis. Changes in T2* qualitatively reflected tissue pO2 changes induced by the interventions. T2* versus pO2 Spearman rank correlations were significant for all interventions, yet quantitative translation of T2*/pO2 correlations obtained for one intervention to another intervention proved not appropriate. The closest T2*/pO2 correlation was found for hypoxia and recovery. The interlayer comparison revealed closest T2*/pO2 correlations for the outer medulla and showed that extrapolation of results obtained for one renal layer to other renal layers must be made with due caution. For T2* to RBF relation, significant Spearman correlations were deduced for all renal layers and for all interventions. T2*/RBF correlations for the cortex and outer medulla were even superior to those between T2* and tissue pO2. The closest T2*/RBF correlation occurred during hypoxia and recovery. Close correlations were observed between T2* and kidney size during hypoxia and recovery and for occlusion and recovery. In both cases, kidney size correlated well with renal vascular conductance

  19. Preclinical Magnetic Resonance Fingerprinting (MRF) at 7 T: Effective Quantitative Imaging for Rodent Disease Models

    Science.gov (United States)

    Gao, Ying; Chen, Yong; Ma, Dan; Jiang, Yun; Herrmann, Kelsey A.; Vincent, Jason A.; Dell, Katherine M.; Drumm, Mitchell L.; Brady-Kalnay, Susann M.; Griswold, Mark A.; Flask, Chris A.; Lu, Lan

    2015-01-01

    High field, preclinical magnetic resonance imaging (MRI) scanners are now commonly used to quantitatively assess disease status and efficacy of novel therapies in a wide variety of rodent models. Unfortunately, conventional MRI methods are highly susceptible to respiratory and cardiac motion artifacts resulting in potentially inaccurate and misleading data. We have developed an initial preclinical, 7.0 T MRI implementation of the highly novel Magnetic Resonance Fingerprinting (MRF) methodology that has been previously described for clinical imaging applications. The MRF technology combines a priori variation in the MRI acquisition parameters with dictionary-based matching of acquired signal evolution profiles to simultaneously generate quantitative maps of T1 and T2 relaxation times and proton density. This preclinical MRF acquisition was constructed from a Fast Imaging with Steady-state Free Precession (FISP) MRI pulse sequence to acquire 600 MRF images with both evolving T1 and T2 weighting in approximately 30 minutes. This initial high field preclinical MRF investigation demonstrated reproducible and differentiated estimates of in vitro phantoms with different relaxation times. In vivo preclinical MRF results in mouse kidneys and brain tumor models demonstrated an inherent resistance to respiratory motion artifacts as well as sensitivity to known pathology. These results suggest that MRF methodology may offer the opportunity for quantification of numerous MRI parameters for a wide variety of preclinical imaging applications. PMID:25639694

  20. Detection of hepatic VX2 carcinomas with ferucarbotran-enhanced magnetic resonance imaging in rabbits: Comparison of nine pulse sequences

    International Nuclear Information System (INIS)

    Kim, Seong Hyun; Choi, Dongil; Lim, Hyo K.; Kim, Min Ju; Jang, Kyung Mi; Kim, Seung Hoon; Lee, Won Jae; Lee, Jongmee; Jeon, Yong Hwan; Lim, Jae Hoon

    2006-01-01

    Objective: To compare the diagnostic performance of a variety of magnetic resonance imaging (MRI) sequences, in order to identify the most effective ferucarbotran-enhanced sequence for the detection of multiple small hepatic VX2 carcinomas in rabbits. Methods: Fifteen rabbits with experimentally induced 135 VX2 carcinomas in the liver underwent ferucarbotran-enhanced MRI using the following nine pulse sequences: a fat-suppressed fast spin-echo (FSE) sequence with two echo times (TE) (proton density- and T2-weighted images), four different T2*-weighted fast multiplanar GRASS (gradient-recalled acquisition in the steady state) (FMPGR) with the combination of three TEs (9, 12, 15 ms, respectively) and two flip angles (20 deg., 80 deg., respectively), T2*-weighted fast multiplanar spoiled GRASS (FMPSPGR), T1-weighted FMPSPGR, and dynamic T1-weighted FMPSPGR. All images were reviewed by three radiologists with quantitative and qualitative analysis. Results: Tumor-to-liver contrast-to-noise ratio of the proton density-weighted FSE sequence was significantly higher than those of the others (p o ) images were superior to those of the others and for the detection of very small hepatic tumors of less than 5 mm, the sensitivities of these sequences were less than 30%. Conclusion: Ferucarbotran-enhanced T2- and proton density-weighted FSE and T2*-weighed FMPGR (TE/flip angle, 12/20 o ) images were found to be the most effective pulse sequences for the detection of multiple small hepatic VX2 carcinomas but these sequences were limited in the detection of very small hepatic tumors of less than 5 mm in size

  1. Magnetic Resonance Imaging for Patellofemoral Chondromalacia: Is There a Role for T2 Mapping?

    Science.gov (United States)

    van Eck, Carola F; Kingston, R Scott; Crues, John V; Kharrazi, F Daniel

    2017-11-01

    Patellofemoral pain is common, and treatment is guided by the presence and grade of chondromalacia. To evaluate and compare the sensitivity and specificity in detecting and grading chondral abnormalities of the patella between proton density fat suppression (PDFS) and T2 mapping magnetic resonance imaging (MRI). Cohort study; Level of evidence, 2. A total of 25 patients who underwent MRI of the knee with both a PDFS sequence and T2 mapping and subsequently underwent arthroscopic knee surgery were included. The cartilage surface of the patella was graded on both MRI sequences by 2 independent, blinded radiologists. Cartilage was then graded during arthroscopic surgery by a sports medicine fellowship-trained orthopaedic surgeon. Reliability, sensitivity, specificity, and accuracy were determined for both MRI methods. The findings during arthroscopic surgery were considered the gold standard. Intraobserver and interobserver agreement for both PDFS (98.5% and 89.4%, respectively) and T2 mapping (99.4% and 91.3%, respectively) MRI were excellent. For T2 mapping, the sensitivity (61%) and specificity (64%) were comparable, whereas for PDFS there was a lower sensitivity (37%) but higher specificity (81%) in identifying cartilage abnormalities. This resulted in a similar accuracy for PDFS (59%) and T2 mapping (62%). Both PDFS and T2 mapping MRI were reliable but only moderately accurate in predicting patellar chondromalacia found during knee arthroscopic surgery.

  2. Inversion recovery RARE: Clinical application of T2-weighted CSF-suppressed rapid sequence

    International Nuclear Information System (INIS)

    Goetz, G.F.; Hennig, J.; Ziyeh, S.

    1995-01-01

    Inversion-Recovery RARE is a strongly T 2 -weighted fast sequence in which the CSF appears dark. This sequence was used in more than 100 patients. Retrospective analysis of 80 patients with cerebrovascular and inflammatory disease was carried out. The IR-RARE sequence proved to be particularly suitable for identifying small lesions in the neighbourhood of the subarachnoid space. We illustrate the typical contrast provided by this sequence, and describe its characteristics, exemplifying the advantages it offers for the diagnosis of multiple sclerosis, cerebral microangiopathy and brain infarction. (orig.) [de

  3. Scan-rescan and intra-observer variability of magnetic resonance imaging of carotid atherosclerosis at 1.5 T and 3.0 T

    International Nuclear Information System (INIS)

    Vidal, Arvin; Wade, Trevor; Rutt, Brian K; Fenster, Aaron; Parraga, Grace; Bureau, Yves; Spence, J David

    2008-01-01

    Carotid atherosclerosis measurements for eight subjects at baseline and 14 ± 2 days later were examined using 1.5 T and 3.0 T magnetic resonance imaging (MRI). A single observer blinded to field strength, subject and timepoint manually segmented carotid artery wall and lumen boundaries in randomized images in five measurement trials. Mean increases in the signal-to-noise ratios (SNR) for T1-weighted images acquired at 3.0 T compared to 1.5 T were 90% (scan) and 80% (rescan). Despite significantly improved SNR and contrast-to-noise ratios (CNR) for images acquired at 3.0 T, vessel wall volume (VWV) intra-observer variability was not significantly different using coefficients of variation (COV), and intraclass correlation coefficients (ICC). VWV interscan variability and consistency at both field strengths were not statistically different (1.5 T/3.0 T COV = 5.7%/7.8%, R 2 = 0.96 for 1.5 T and R 2 = 0.87 for 3.0 T). A two-way analysis of variance showed a VWV dependence on field strength but not scan timepoint. In addition, a paired t-test showed significant differences in VWV measured at 3.0 T as compared to 1.5 T. These results suggest that although images acquired at 1.5 T have lower SNR and CNR VWV, measurement variability was not significantly different from 3.0 T VWV and that VWV is field-strength dependent which may be an important consideration for longitudinal studies.

  4. Scan-rescan and intra-observer variability of magnetic resonance imaging of carotid atherosclerosis at 1.5 T and 3.0 T

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, Arvin; Wade, Trevor; Rutt, Brian K; Fenster, Aaron; Parraga, Grace [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, N6A 5K8 (Canada); Bureau, Yves [Graduate Program in Biomedical Engineering, University of Western Ontario, London, N6A 5B9 (Canada); Spence, J David [Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, 1400 Western Road, London, N6A 5K8 (Canada)], E-mail: avidal@imaging.robarts.ca, E-mail: ybureau@lawsonimaging.ca, E-mail: twade@imaging.robarts.ca, E-mail: DSpence@robarts.ca, E-mail: brutt@imaging.robarts.ca, E-mail: afenster@imaging.robarts.ca, E-mail: gep@imaging.robarts.ca

    2008-12-07

    Carotid atherosclerosis measurements for eight subjects at baseline and 14 {+-} 2 days later were examined using 1.5 T and 3.0 T magnetic resonance imaging (MRI). A single observer blinded to field strength, subject and timepoint manually segmented carotid artery wall and lumen boundaries in randomized images in five measurement trials. Mean increases in the signal-to-noise ratios (SNR) for T1-weighted images acquired at 3.0 T compared to 1.5 T were 90% (scan) and 80% (rescan). Despite significantly improved SNR and contrast-to-noise ratios (CNR) for images acquired at 3.0 T, vessel wall volume (VWV) intra-observer variability was not significantly different using coefficients of variation (COV), and intraclass correlation coefficients (ICC). VWV interscan variability and consistency at both field strengths were not statistically different (1.5 T/3.0 T COV = 5.7%/7.8%, R{sup 2} = 0.96 for 1.5 T and R{sup 2} = 0.87 for 3.0 T). A two-way analysis of variance showed a VWV dependence on field strength but not scan timepoint. In addition, a paired t-test showed significant differences in VWV measured at 3.0 T as compared to 1.5 T. These results suggest that although images acquired at 1.5 T have lower SNR and CNR VWV, measurement variability was not significantly different from 3.0 T VWV and that VWV is field-strength dependent which may be an important consideration for longitudinal studies.

  5. Anomalous magnetic aftereffect in Nd3(Fe,T)29 (T = Ti or Re) intermetallic compounds

    International Nuclear Information System (INIS)

    Collocott, S.J.; Dunlop, J.B.; Gwan, P.B.

    1999-01-01

    Full text: The intermetallic compounds Nd 3 (Fe,Ti) 29 and Nd 3 (Fe,Re) 29 order ferromagnetically with Curie Temperatures, T c , of 430 and 370 K respectively. They have a monoclinic crystal structure, space group A2/m (Nd 3 (Fe,Ti) 29 type) with two rare earth sites and eleven Fe(T) sites, which is an intermediate structure between the rhombohedral Th 2 Zn 17 and tetragonal ThMn 12 structures, and is closely related to hexagonal CaCu 5 . Ferromagnetic materials, depending on their magnetic prehistory, may exhibit a time dependent magnetisation. The term 'magnetic aftereffect' is used to describe this behaviour, which may fall into three categories: 1. Reversible or diffusion aftereffect which is associated with the diffusion of impurity atoms or holes within the ferromagnetic lattice. 2. The irreversible or fluctuation aftereffect, which results in a logarithmic time dependence of magnetisation, J(t)=J(0)+Sln(t+t 0 ), where S is the magnetic viscosity and t 0 a parameter to establish the origin of the time scale measurements. 3. Quantum tunnelling of magnetisation which is observed at very low temperatures. A range of magnetic aftereffects have been observed in both Nd 3 (Fe,Ti) 29 and Nd 3 (Fe,Re) 29 . Of particular interest is the case where the material is fully saturated by application of a field in the positive direction, the applied field is then reversed to trace out part of the major demagnetisation curve into the third quadrant, and thence along a recoil curve, such that in zero applied field the magnetisation is zero (H=0, J=0). (This corresponds to dc field magnetisation.) This magnetic prehistory results in two interesting effects; spontaneous remagnetisation e.g. remagnetisation without application of an external field, and thermal remagnetisation e.g. an increase in magnetisation as the temperature is increased. Additionally, the behaviour of the magnetic viscosity has been explored on the major demagnetisation curve as a function of temperature

  6. Radiographs and low field MRI (0.2T) as predictors of efficacy in a weight loss trial in obese women with knee osteoarthritis

    DEFF Research Database (Denmark)

    Gudbergsen, Henrik; Boesen, Mikael; Christensen, Robin

    2011-01-01

    To study the predictive value of baseline radiographs and low-field (0.2T) MRI scans for the symptomatic outcome of clinically significant weight loss in obese patients with knee osteoarthritis.......To study the predictive value of baseline radiographs and low-field (0.2T) MRI scans for the symptomatic outcome of clinically significant weight loss in obese patients with knee osteoarthritis....

  7. Diagnosis of acute ischemic stroke based on time-to-peak and diffusion-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Keisuke; Eguchi, Tsuneyoshi; Sora, Shigeo; Izumi, Masafumi; Hiyama, Hirofumi [Kameda General Hospital, Kamogawa, Chiba (Japan); Ueki, Keisuke [Tokyo Univ. (Japan). Hospital

    2002-07-01

    Rapid and accurate diagnosis of the hemodynamics of the brain is essential for the treatment of acute ischemic stroke. This study investigated whether time-to-peak and diffusion-weighted magnetic resonance (MR) imaging are useful for predicting the course of stroke. Fourteen patients with non-lacunar acute ischemic stroke underwent emergent MR imaging within 24 hours from the onset followed by cerebral angiography and xenon-enhanced computed tomography (CT). Serial CT was obtained to monitor changes in the size and nature of the infarct. Volumes of the abnormal lesions demonstrated on time-to-peak (V{sub T}) or diffusion-weighted (V{sub D}) images were measured, and the ratio of V{sub T} to V{sub D} was calculated. Based on this ratio, patients were classified into three groups: Group 1 (V{sub T}/V{sub D} 0.5-1.5, n=9), Group 2 (V{sub T}/V{sub D}>1.5, n=3), and Group 3 (V{sub T}/V{sub D}<0.5, n=2). The size of the infarct detected as a low-density area on serial CT scans did not change significantly throughout the course in Group 1 patients, but showed enlargement in all three patients in Group 2. Two patients in Group 3 had major trunk occlusion followed by spontaneous reperfusion, and both developed hemorrhagic transformation. Our study showed that classification of ischemic stroke based on the V{sub T}/V{sub D} ratio was predictive of the time course of the infarct, and may be useful in selecting the initial therapeutic procedure immediately after the onset of stroke. (author)

  8. Casein-Coated Fe5C2 Nanoparticles with Superior r2 Relaxivity for Liver-Specific Magnetic Resonance Imaging.

    Science.gov (United States)

    Cowger, Taku A; Tang, Wei; Zhen, Zipeng; Hu, Kai; Rink, David E; Todd, Trever J; Wang, Geoffrey D; Zhang, Weizhong; Chen, Hongmin; Xie, Jin

    2015-01-01

    Iron oxide nanoparticles have been extensively used as T2 contrast agents for liver-specific magnetic resonance imaging (MRI). The applications, however, have been limited by their mediocre magnetism and r2 relaxivity. Recent studies show that Fe5C2 nanoparticles can be prepared by high temperature thermal decomposition. The resulting nanoparticles possess strong and air stable magnetism, suggesting their potential as a novel type of T2 contrast agent. To this end, we improve the synthetic and surface modification methods of Fe5C2 nanoparticles, and investigated the impact of size and coating on their performances for liver MRI. Specifically, we prepared 5, 14, and 22 nm Fe5C2 nanoparticles and engineered their surface by: 1) ligand addition with phospholipids, 2) ligand exchange with zwitterion-dopamine-sulfonate (ZDS), and 3) protein adsorption with casein. It was found that the size and surface coating have varied levels of impact on the particles' hydrodynamic size, viability, uptake by macrophages, and r2 relaxivity. Interestingly, while phospholipid- and ZDS-coated Fe5C2 nanoparticles showed comparable r2, the casein coating led to an r2 enhancement by more than 2 fold. In particular, casein coated 22 nm Fe5C2 nanoparticle show a striking r2 of 973 mM(-1)s(-1), which is one of the highest among all of the T2 contrast agents reported to date. Small animal studies confirmed the advantage of Fe5C2 nanoparticles over iron oxide nanoparticles in inducing hypointensities on T2-weighted MR images, and the particles caused little toxicity to the host. The improvements are important for transforming Fe5C2 nanoparticles into a new class of MRI contrast agents. The observations also shed light on protein-based surface modification as a means to modulate contrast ability of magnetic nanoparticles.

  9. The Effect of the Degree of Luminal Contrast-Enhancement on CT Measurement of Plaque Size: A Comparison with T1-weighted Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Choi, Byoung Wook; Hur, Jin; Lee, Hye Jeong; Kim, Young Jin; Choe, Kyu Ok; Kim, Tae Hoon

    2010-01-01

    We studied early and delayed contrast-enhanced CT to determine the effects of the degree of luminal enhancement on the measurement of plaque size compared to T1-weighted MRI. T1-weighted MRI and a two-phase contrast-enhanced CT was performed in 5 New Zealand white rabbits with atherosclerosis. Early-phase images were acquired during an expected peak enhancement period of the lumen; delayed-phase images were acquired 240 sec after administration of the contrast media. Anteroposterior and lateral luminal diameters (APD, LD), luminal area (LA), total vessel area (TVA), and plaque area (PA) of the aorta were measured on MRI and CT, respectively and compared to each other. A total of 78 slices of the aorta were analyzed. PA, measured on T1-weighted MR images, was significantly greater than PA for both early-phase and delayed-phase CT (p 2 (p 2 (p 2 (p = 0.159) for MRI vs. early-phase CT, MRI vs. delayed-phase CT, and early-phase CT vs. delayed-phase CT, respectively. Different luminal densities by contrast enhancement do not affect the CT measurement of plaque area for the detection of obstructive coronary artery disease

  10. Trapping a magnetic field of 7.9 T using a bulk magnet fabricated from stack of coated conductors

    International Nuclear Information System (INIS)

    Tamegai, T.; Hirai, T.; Sun, Y.; Pyon, S.

    2016-01-01

    Highlight: • A bulk magnet is fabricated using double stack of coated conductors (CC). • Magneto-optical imaging of the CC confirmed its homogeneity. • The fabricated bulk magnet has successfully trapped a magnetic field of 7.9 T. • The trapped magnetic field is consistent with the magnetic induction calculated from J_c(B) characteristics of the CC. - Abstract: We have fabricated a bulk magnet using double stack, each 130 layers, of short segments of coated conductors (CCs). The bulk magnet is magnetized by field-cooling in a magnetic field of 9 T down to 4.2 K. After reducing the magnetic field down to zero, we have successfully trapped a magnetic field of 7.9 T at the centre of the double stack. The magnetic field profile of the bulk magnet is calculated by fully considering the J_c(B) characteristics of the short segment of the CC. The trapped magnetic field values measured by Hall probes at three locations near the centre of the double stacks agree reasonably well with the calculated magnetic induction.

  11. Breath-hold dark-blood T{sub 2}-weighted MR imaging of the heart. Estimation of optimum preset repetition time

    Energy Technology Data Exchange (ETDEWEB)

    Sakuma, Toshiharu; Yamada, Naoaki; Yamasaki, Hidetoshi; Kita, Yoshinobu; Fujii, Hiroshi [National Cardiovascular Center, Suita, Osaka (Japan)

    1999-03-01

    It has recently become possible to obtain T{sub 2}-weighted images using turbo spin echo with a preparation pulse to inhibit the signal from flowing blood (dark blood turbo spin echo: DB-TSE) during breath holding. In order to obtain higher-quality T{sub 2}-weighted images of the heart, we assessed the optimum preset repetition time (TR preset), the interval between the dark blood preparation pulse and the end of data acquisition on DB-TSE. DB-TSE left ventricular short-axis images were obtained with varying TR presets in eight volunteers. Signal intensity was measured for the myocardium and blood in the left ventricular cavity, and the signal intensity ratio of myocardium to blood was calculated. The optimum TR preset was determined so as to give the highest signal intensity ratio of myocardium to blood. A comparison was made of the myocardium-to-blood ratios between the eight volunteers and nine patients. The optimum TR preset changed according to the cardiac cycle. By using the optimum TR preset, we obtained the peak signal intensity ratios in the volunteers and the patients. By using DB-TSE with the optimum TR preset for the cardiac cycle, we can obtain better quality T{sub 2}-weighted images of the heart. (author)

  12. Quantitative and Qualitative Assessment of Pulmonary Emphysema with T2-Weighted PROPELLER MRI in a High-Risk Population Compared to Low-Dose CT.

    Science.gov (United States)

    Meier-Schroers, Michael; Sprinkart, Alois Martin; Becker, Manuel; Homsi, Rami; Thomas, Daniel

    2018-03-07

     To determine the suitability of T2-weighted PROPELLER MRI for the assessment of pulmonary emphysema.  60 participants in a lung cancer screening program (30 subjects with pulmonary emphysema, and 30 control subjects without emphysema) were included for this retrospective study. All subjects were examined with low-dose CT (LDCT) and MRI within the screening program. The use of a T2-weighted PROPELLER sequence for the assessment of emphysema was analyzed and correlated with the results of LDCT. The presence and the extent of pulmonary emphysema were first assessed qualitatively using a three-point score, and then quantitatively with a semi-automated software program to obtain emphysema indices.  All 30 cases with pulmonary emphysema were accurately detected by MRI. There were 3 cases with emphysema according to MRI without emphysematous changes on LDCT (false-positive results). The qualitative scores as well as the emphysema indices were significantly higher in the emphysema group compared to the control group for MRI and LDCT (p emphysema group and r = 0.668/p emphysema index: r = 0.960/p emphysema group and r = 0.746/p pulmonary emphysema may be assessed qualitatively and quantitatively by T2-weighted PROPELLER MRI with very good correlation to LDCT.   · T2-weighted PROPELLER MRI may be suitable for the assessment of pulmonary emphysema.. · There was significant correlation between MRI and LDCT regarding qualitative scores and quantitative emphysema indices in our study with correlation coefficients for different subgroups ranging from r = 0.668 to r = 0.960.. · T2-weighted PROPELLER MRI may have the potential to be used for follow-up examinations in patients with severe emphysema to avoid radiation exposure of repeated CTs.. · Meier-Schroers M, Sprinkart AM, Becker M et al. Quantitative and Qualitative Assessment of Pulmonary Emphysema with T2-Weighted PROPELLER MRI in a High-Risk Population Compared to Low-Dose CT

  13. Objective measurement of minimal fat in normal skeletal muscles of healthy children using T2 relaxation time mapping (T2 maps) and MR spectroscopy.

    Science.gov (United States)

    Kim, Hee Kyung; Serai, Suraj; Merrow, Arnold C; Wang, Lily; Horn, Paul S; Laor, Tal

    2014-02-01

    Various skeletal muscle diseases result in fatty infiltration, making it important to develop noninvasive biomarkers to objectively measure muscular fat. We compared T2 relaxation time mapping (T2 maps) and magnetic resonance spectroscopy (MRS) with physical characteristics previously correlated with intramuscular fat to validate T2 maps and MRS as objective measures of skeletal muscle fat. We evaluated gluteus maximus muscles in 30 healthy boys (ages 5-19 years) at 3 T with T1-weighted images, T2-W images with fat saturation, T2 maps with and without fat saturation, and MR spectroscopy. We calculated body surface area (BSA), body mass index (BMI) and BMI percentile (BMI %). We performed fat and inflammation grading on T1-W imaging and fat-saturated T2-W imaging, respectively. Mean T2 values from T2 maps with fat saturation were subtracted from T2 maps without fat saturation to determine T2 fat values. We obtained lipid-to-water ratios by MR spectroscopy. Pearson correlation was used to assess relationships between BSA, BMI, BMI %, T2 fat values, and lipid-to-water ratios for each boy. Twenty-four boys completed all exams; 21 showed minimal and 3 showed no fatty infiltration. None showed muscle inflammation. There was correlation between BSA, BMI, and BMI %, and T2 fat values (P values and lipid-to-water ratios (P skeletal muscles, even in microscopic amounts, and validate each other. Both techniques might enable detection of minimal pathological fatty infiltration in children with skeletal muscle disorders.

  14. Application of EPI diffusion-weighted and Gd-DTPA T2* perfusion imaging in the diagnosis of brain ischemia

    International Nuclear Information System (INIS)

    Han Hongbin; Xie Jingxia

    1998-01-01

    Purpose: To study the MR and CT appearances of brain ischemia on diffusion-weighted imaging (DWI) and evaluate the role of EPI ADC-map, DWI and T 2 * perfusion imaging in acute stroke. Methods: DWI or ADC-map and routine T 1 WI and T 2 WI were performed in 36 patients with stroke (the time after onset of stroke: 2 hours - 2 months). Among them, 12 cases had perfusion imaging simultaneously. Results: Gd-DTPA T 2 * perfusion imaging demonstrated decrease of rrCBV and rrCBF in 10 cases; identical in 1 case and increase in 1 case. The mean transit time in the diseased area was longer than that of the contralateral corresponding region (paired t test: P 2 * perfusion imaging can demonstrate the decrease and restoration of CBF in the brain ischemic regions. DWI and ADC-map are highly valuable in the early diagnosis and monitoring the development of brain ischemic disease

  15. The use of diffusion-weighted magnetic resonance imaging in the differentiation between benign and malignant breast lesions

    International Nuclear Information System (INIS)

    Pereira, Fernanda Philadelpho Arantes; Martins, Gabriela; Domingues, Marisa Nassar Aidar; Domingues, Romeu Cortes; Figueiredo, Eduardo; Fonseca, Lea Mirian Barbosa da

    2009-01-01

    Objective: to study the utility of diffusion-weighted magnetic resonance imaging in the differentiation between benign and malignant breast lesions. Materials and methods: forty-five women (mean age, 46.1 years) with 52 focal breast lesions underwent diffusion-weighted magnetic resonance imaging. The calculation of apparent diffusion coefficient (ADC) was based on the ADC map reflecting five b values (0, 250, 500, 750, and 1000 s/mm 2 ). The mean ADC value of each lesion was correlated with imaging findings and histopathologic results. Cutoff ADC, sensitivity and specificity of diffusion-weighted imaging in the differentiation between benign and malignant lesions were calculated. P -3 mm 2 /s) as compared with benign lesions (1.50 ± 0.34 x 10 -3 mm 2 /s) (P < 0.0001). Diffusion-weighted imaging showed high sensitivity and specificity (both, 92.3%) in the differentiation between benign and malignant lesions. Conclusion: diffusion-weighted imaging is a potential resource as an adjuvant to breast magnetic resonance imaging to differentiate benign from malignant lesions. Such sequence can be easily added to the standard breast magnetic resonance imaging protocol, without implying any significant increase in examination time. (author)

  16. Magnetic resonance imaging of the fetal gallbladder and bile

    International Nuclear Information System (INIS)

    Brugger, Peter C.; Weber, Michael; Prayer, Daniela

    2010-01-01

    To study the magnetic resonance imaging (MRI) appearance of the fetal gallbladder with special reference to fetal gallbladder sludge. In a retrospective study of 512 fetuses without gastrointestinal abnormalities, we classified the gallbladder MR appearances into patterns based on the signal intensity (SI) of bile on T1-weighted and T2-weighted sequences. We analysed the ratio of T1-weighted SI of bile. Maximum gallbladder width was correlated with gestational weeks (GW) using non-linear regression analysis and compared between various imaging patterns with one-way ANOVA. Five age-dependent patterns of the MRI appearance were found: (1) SI of bile was T2-weighted hyperintense and T1-weighted hypointense (78.5%); (2) presented with T2-weighted hyperintensity and T1-weighted signal isointense to liver (10.4%); (3) moderate hyperintense T2-weighted SI, T1-weighted SI hyperintense to liver (4.9%); (4) SI was T2-weighted isointense and T1-weighted hyperintense to liver (3.7%); (5) pronounced T2-weighted hypointensity and marked T1-weighted hyperintensity (2.5%). Pattern 1 was exclusively found before 27 GW, while patterns 2-5 increased in frequency after 30 GW. The MRI appearance of the fetal gallbladder is variable; fetal bile shows age-dependent SI changes that may cause non-visualisation of the gallbladder. This may be due to sludge and/or accumulation of paramagnetic substances suspended within gallbladder mucus. (orig.)

  17. Magnetic resonance imaging of the fetal gallbladder and bile

    Energy Technology Data Exchange (ETDEWEB)

    Brugger, Peter C. [Medical University of Vienna, Integrative Morphology Group, Center for Anatomy and Cell Biology, Vienna (Austria); Weber, Michael [Medical University of Vienna, Department of Radiology, Vienna (Austria); Prayer, Daniela [Medical University of Vienna, Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Vienna (Austria)

    2010-12-15

    To study the magnetic resonance imaging (MRI) appearance of the fetal gallbladder with special reference to fetal gallbladder sludge. In a retrospective study of 512 fetuses without gastrointestinal abnormalities, we classified the gallbladder MR appearances into patterns based on the signal intensity (SI) of bile on T1-weighted and T2-weighted sequences. We analysed the ratio of T1-weighted SI of bile. Maximum gallbladder width was correlated with gestational weeks (GW) using non-linear regression analysis and compared between various imaging patterns with one-way ANOVA. Five age-dependent patterns of the MRI appearance were found: (1) SI of bile was T2-weighted hyperintense and T1-weighted hypointense (78.5%); (2) presented with T2-weighted hyperintensity and T1-weighted signal isointense to liver (10.4%); (3) moderate hyperintense T2-weighted SI, T1-weighted SI hyperintense to liver (4.9%); (4) SI was T2-weighted isointense and T1-weighted hyperintense to liver (3.7%); (5) pronounced T2-weighted hypointensity and marked T1-weighted hyperintensity (2.5%). Pattern 1 was exclusively found before 27 GW, while patterns 2-5 increased in frequency after 30 GW. The MRI appearance of the fetal gallbladder is variable; fetal bile shows age-dependent SI changes that may cause non-visualisation of the gallbladder. This may be due to sludge and/or accumulation of paramagnetic substances suspended within gallbladder mucus. (orig.)

  18. Model-based T{sub 2} relaxometry using undersampled magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sumpf, Tilman

    2013-11-01

    T{sub 2} relaxometry refers to the quantitative determination of spin-spin relaxation times in magnetic resonance imaging (MRI). Particularly in clinical diagnostics, the method provides important information about tissue structures and respective pathologic alterations. Unfortunately, it also requires comparatively long measurement times which preclude widespread practical applications. To overcome such limitations, a so-called model-based reconstruction concept has recently been proposed. The method allows for the estimation of spin-density and T{sub 2} parameter maps from only a fraction of the usually required data. So far, promising results have been reported for a radial data acquisition scheme. However, due to technical reasons, radial imaging is only available on a very limited number of MRI systems. The present work deals with the realization and evaluation of different model-based T{sub 2} reconstruction methods that are applicable for the most widely available Cartesian (rectilinear) acquisition scheme. The initial implementation is based on the conventional assumption of a mono-exponential T{sub 2} signal decay. A suitable sampling scheme as well as an automatic scaling procedure are developed, which remove the necessity of manual parameter tuning. As demonstrated for human brain MRI data, the technique allows for a more than 5-fold acceleration of the underlying data acquisition. Furthermore, general limitations and specific error sources are identified and suitable simulation programs are developed for their detailed analysis. In addition to phase variations in image space, the simulations reveal truncation effects as a relevant cause of reconstruction artifacts. To reduce the latter, an alternative model formulation is developed and tested. For noise-free simulated data, the method yields an almost complete suppression of associated artifacts. Residual problems in the reconstruction of experimental MRI data point to the predominant influence of other

  19. Revised PROPELLER for T2-weighted imaging of the prostate at 3 Tesla: impact on lesion detection and PI-RADS classification

    International Nuclear Information System (INIS)

    Meier-Schroers, Michael; Marx, Christian; Schmeel, Frederic Carsten; Wolter, Karsten; Block, Wolfgang; Sprinkart, Alois Martin; Traeber, Frank; Schild, Hans Heinz; Kukuk, Guido Matthias; Gieseke, Juergen; Willinek, Winfried

    2018-01-01

    To evaluate revised PROPELLER (RevPROP) for T2-weighted imaging (T2WI) of the prostate as a substitute for turbo spin echo (TSE). Three-Tesla MR images of 50 patients with 55 cancer-suspicious lesions were prospectively evaluated. Findings were correlated with histopathology after MRI-guided biopsy. T2 RevPROP, T2 TSE, diffusion-weighted imaging, dynamic contrast enhancement, and MR-spectroscopy were acquired. RevPROP was compared to TSE concerning PI-RADS scores, lesion size, lesion signal-intensity, lesion contrast, artefacts, and image quality. There were 41 carcinomas in 55 cancer-suspicious lesions. RevPROP detected 41 of 41 carcinomas (100%) and 54 of 55 lesions (98.2%). TSE detected 39 of 41 carcinomas (95.1%) and 51 of 55 lesions (92.7%). RevPROP showed fewer artefacts and higher image quality (each p < 0.001). No differences were observed between single and overall PI-RADS scores based on RevPROP or TSE (p = 0.106 and p = 0.107). Lesion size was not different (p = 0.105). T2-signal intensity of lesions was higher and T2-contrast of lesions was lower on RevPROP (each p < 0.001). For prostate cancer detection RevPROP is superior to TSE with respect to motion robustness, image quality and detection rates of lesions. Therefore, RevPROP might be used as a substitute for T2WI. (orig.)

  20. Revised PROPELLER for T2-weighted imaging of the prostate at 3 Tesla: impact on lesion detection and PI-RADS classification

    Energy Technology Data Exchange (ETDEWEB)

    Meier-Schroers, Michael; Marx, Christian; Schmeel, Frederic Carsten; Wolter, Karsten; Block, Wolfgang; Sprinkart, Alois Martin; Traeber, Frank; Schild, Hans Heinz; Kukuk, Guido Matthias [University Hospital Bonn, Department of Radiology, Bonn (Germany); Gieseke, Juergen [Philips Healthcare Germany, Hamburg (Germany); Willinek, Winfried [Hospital of Barmherzige Brueder, Department of Radiology, Neuroradiology, Sonography and Nuclear Medicine, Trier (Germany)

    2018-01-15

    To evaluate revised PROPELLER (RevPROP) for T2-weighted imaging (T2WI) of the prostate as a substitute for turbo spin echo (TSE). Three-Tesla MR images of 50 patients with 55 cancer-suspicious lesions were prospectively evaluated. Findings were correlated with histopathology after MRI-guided biopsy. T2 RevPROP, T2 TSE, diffusion-weighted imaging, dynamic contrast enhancement, and MR-spectroscopy were acquired. RevPROP was compared to TSE concerning PI-RADS scores, lesion size, lesion signal-intensity, lesion contrast, artefacts, and image quality. There were 41 carcinomas in 55 cancer-suspicious lesions. RevPROP detected 41 of 41 carcinomas (100%) and 54 of 55 lesions (98.2%). TSE detected 39 of 41 carcinomas (95.1%) and 51 of 55 lesions (92.7%). RevPROP showed fewer artefacts and higher image quality (each p < 0.001). No differences were observed between single and overall PI-RADS scores based on RevPROP or TSE (p = 0.106 and p = 0.107). Lesion size was not different (p = 0.105). T2-signal intensity of lesions was higher and T2-contrast of lesions was lower on RevPROP (each p < 0.001). For prostate cancer detection RevPROP is superior to TSE with respect to motion robustness, image quality and detection rates of lesions. Therefore, RevPROP might be used as a substitute for T2WI. (orig.)

  1. Clinical utility of partial flip angle T2-weighted spin-echo imaging of the brain

    International Nuclear Information System (INIS)

    Chang, K.H.; Yi, J.G.; Han, M.H.; Han, M.C.; Kim, C.W.; Cho, M.H.; Cho, Z.H.

    1990-01-01

    To assess the clinical usefulness of partial flip angle (PFA) spin-echo (SE) brain imaging, a total of eighty patients were examined with both conventional double echo T2-weighted SE (2500/30, 80/90deg/one excitation) and PFA double echo SE (1200/30, 70/45deg/two excitations) on 2.0T system. Two comparative studies were performed: (1) In 65 patients PFA SE technique was compared with conventional SE without flow compensating gradients, and (2) in 15 patients the former was compared with the latter with flow compensating gradients. Imaging time was nearly identical in each sequence. In both studies we found that PFA T2-weighted SE images were almost identical to those obtained with the conventional SE technique in the contrast characteristics and the detection rate of the abnormalities (100%, 85/85 lesions), and more importantly, PFA SE revealed few flow artifacts in the brain stem, temporal lobes and basal ganglia which were frequently seen on conventional SE without flow compensating gradients. Additionally, PFA SE images demonstrated no suppression of CSF flow void in the aqueduct which was commonly seen on conventional SE with flow compensating gradients. In overall image quality, the PFA SE images, particularly the second echo images, were almost comparable with those of conventional SE with flow compensating gradients. A flip angle of 45deg seems to be close to Ernst angle, the angle at which maximum signal occurs, for a given TR of 1200 msec for CSF and most of the abnormalities containing higher water content. In conclusion, PFA SE sequence (i.e. 1200/30, 70/45deg/2) appears to be useful as a primary or an adjunctive technique in certain clinical circumstances, particularly in imaging of hydrocephalic patients for assessing aqueductal patency. (orig.)

  2. Highly stable silica-coated manganese ferrite nanoparticles as high-efficacy T2 contrast agents for magnetic resonance imaging

    Science.gov (United States)

    Ahmad, Ashfaq; Bae, Hongsub; Rhee, Ilsu

    2018-05-01

    Highly stable silica-coated manganese ferrite nanoparticles were fabricated for application as magnetic resonance imagining (MRI) contrast agents. The manganese ferrite nanoparticles were synthesized using a hydrothermal technique and coated with silica. The particle size was investigated using transmission electron microscopy and was found to be 40-60 nm. The presence of the silica coating on the particle surface was confirmed by Fourier transform infrared spectroscopy. The crystalline structure was investigated by X-ray diffraction, and the particles were revealed to have an inverse spinel structure. Superparamagnetism was confirmed by the magnetic hysteresis curves obtained using a vibrating sample magnetometer. The efficiency of the MRI contrast agents was investigated by using aqueous solutions of the particles in a 4.7 T MRI scanner. The T1 and T2 relaxivities of the particles were 1.42 and 60.65 s-1 mM-1, respectively, in water. The ratio r2/r1 was 48.91, confirming that the silica-coated manganese ferrite nanoparticles were suitable high-efficacy T2 contrast agents.

  3. Contrast-enhanced dynamic and diffusion-weighted magnetic resonance imaging at 3.0 T to assess early-stage nasopharyngeal carcinoma.

    Science.gov (United States)

    Ni, Liangping; Liu, Ying

    2018-04-01

    The present study aimed to assess early-stage nasopharyngeal carcinoma (NPC) with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) at 3.0 T. A total of 44 patients newly diagnosed with NPC were included in the present study. All patients underwent MR examination at 3.0 T using DCE-MRI and DWI. The volume transfer constant ( K trans ), flux rate constant between extravascular extracellular space and plasma ( K ep ), the volume of extravascular extracellular space per unit volume of tissue ( V e ) and the apparent diffusion coefficient (ADC) of tumours were investigated. Furthermore, the correlation between clinical stages and ADC value and K trans were analysed. The diagnostic accuracy of K trans and ADC were estimated using receiver operating characteristic curves. NPC stage correlated positively with K trans and negatively with ADC values. Additionally, tumour K trans negatively correlated with ADC value. The sensitivity and accuracy of combined K trans and ADC in distinguishing between stage II and stage III and stage III and IV were higher than the values of either measurement used separately. The present study suggested that K trans and ADC derived from DCE-MRI and DWI may be useful to detect stage early NPC accurately. K trans and ADC in combination were superior than either alone.

  4. Magnetic phase diagram of Ce2Fe17 under high pressures in high magnetic fields

    International Nuclear Information System (INIS)

    Ishikawa, Fumihiro; Goto, Tsuneaki; Fujii, Hironobu

    2003-01-01

    The magnetization of Ce 2 Fe 17 was precisely measured under high pressures up to 1.2 GPa in magnetic fields up to 18 T. The magnetic phase diagram in the B-T plane is determined at 0, 0.3, 0.4, 0.6, 0.9 and 1.2 GPa. At 0 GPa, five magnetic phases exist and the application of high pressure produces two additional magnetic phases. The shape of the phase diagram changes drastically with increasing pressure

  5. Degenerative disc disease of the lumbar spine: a prospective comparison of fast T1-weighted fluid-attenuated inversion recovery and T1-weighted turbo spin echo MR imaging

    International Nuclear Information System (INIS)

    Erdem, L. Oktay; Erdem, C. Zuhal; Acikgoz, Bektas; Gundogdu, Sadi

    2005-01-01

    Objective: To compare fast T1-weighted fluid-attenuated inversion recovery (FLAIR) and T1-weighted turbo spin-echo (TSE) imaging of the degenerative disc disease of the lumbar spine. Materials and methods: Thirty-five consecutive patients (19 females, 16 males; mean age 41 years, range 31-67 years) with suspected degenerative disc disease of the lumbar spine were prospectively evaluated. Sagittal images of the lumbar spine were obtained using T1-weighted TSE and fast T1-weighted FLAIR sequences. Two radiologists compared these sequences both qualitatively and quantitatively. Results: On qualitative evaluation, CSF nulling, contrast at the disc-CSF interface, the disc-spinal cord (cauda equina) interface, and the spinal cord (cauda equina)-CSF interface of fast T1-weighted FLAIR images were significantly higher than those for T1-weighted TSE images (P < 0.001). On quantitative evaluation of the first 15 patients, signal-to-noise ratios of cerebrospinal fluid of fast T1-weighted FLAIR imaging were significantly lower than those for T1-weighted TSE images (P < 0.05). Contrast-to-noise ratios of spinal cord/CSF and normal bone marrow/disc for fast T1-weighted FLAIR images were significantly higher than those for T1-weighted TSE images (P < 0.05). Conclusion: Results in our study have shown that fast T1-weighted FLAIR imaging may be a valuable imaging modality in the armamentarium of lumbar spinal T1-weighted MR imaging, because the former technique has definite superior advantages such as CSF nulling, conspicuousness of the normal anatomic structures and changes in the lumbar spinal discogenic disease and image contrast and also almost equally acquisition times

  6. Degenerative disc disease of the lumbar spine: a prospective comparison of fast T1-weighted fluid-attenuated inversion recovery and T1-weighted turbo spin echo MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Erdem, L. Oktay [Department of Radiology, Zonguldak Karaelmas University, School of Medicine, 6700 Kozlu, Zonguldak (Turkey)]. E-mail: sunarerdem@yahoo.com; Erdem, C. Zuhal [Department of Radiology, Zonguldak Karaelmas University, School of Medicine, 6700 Kozlu, Zonguldak (Turkey); Acikgoz, Bektas [Department of Neurosurgery, Zonguldak Karaelmas University, School of Medicine, Zonguldak (Turkey); Gundogdu, Sadi [Department of Radiology, Zonguldak Karaelmas University, School of Medicine, 6700 Kozlu, Zonguldak (Turkey)

    2005-08-01

    Objective: To compare fast T1-weighted fluid-attenuated inversion recovery (FLAIR) and T1-weighted turbo spin-echo (TSE) imaging of the degenerative disc disease of the lumbar spine. Materials and methods: Thirty-five consecutive patients (19 females, 16 males; mean age 41 years, range 31-67 years) with suspected degenerative disc disease of the lumbar spine were prospectively evaluated. Sagittal images of the lumbar spine were obtained using T1-weighted TSE and fast T1-weighted FLAIR sequences. Two radiologists compared these sequences both qualitatively and quantitatively. Results: On qualitative evaluation, CSF nulling, contrast at the disc-CSF interface, the disc-spinal cord (cauda equina) interface, and the spinal cord (cauda equina)-CSF interface of fast T1-weighted FLAIR images were significantly higher than those for T1-weighted TSE images (P < 0.001). On quantitative evaluation of the first 15 patients, signal-to-noise ratios of cerebrospinal fluid of fast T1-weighted FLAIR imaging were significantly lower than those for T1-weighted TSE images (P < 0.05). Contrast-to-noise ratios of spinal cord/CSF and normal bone marrow/disc for fast T1-weighted FLAIR images were significantly higher than those for T1-weighted TSE images (P < 0.05). Conclusion: Results in our study have shown that fast T1-weighted FLAIR imaging may be a valuable imaging modality in the armamentarium of lumbar spinal T1-weighted MR imaging, because the former technique has definite superior advantages such as CSF nulling, conspicuousness of the normal anatomic structures and changes in the lumbar spinal discogenic disease and image contrast and also almost equally acquisition times.

  7. Reticuloendothelial negative contrast media for hepatocellular carcinoma. Initial comparison of chondroitin sulfate iron colloid and Ferrixan in fast T2-weighted MR imaging

    International Nuclear Information System (INIS)

    Sugihara, Shuji; Suto, Yuji; Kamba, Masayuki; Yoshida, Kotaro

    1996-01-01

    Chondroitin sulfate iron colloid (CSIC), a paramagnetic substance, and Ferrixan (SHU555A), a superparamagnetic substance, were administered to 20 patients with 26 nodules of hepatocellular carcinoma, and the visualization of the lesions by fast T2-weighted magnetic resonance imaging (MRI) was quantitatively evaluated. Conventional spin-echo (CSE), turbo spin-echo (TSE), and turbo gradient spin-echo (TGSE) sequences were performed in all patients before and after the administration of the iron colloid preparations. The signal-to-noise ratio (SNR) in the liver decreased significantly after administration of iron colloid preparations by all sequences and at all doses. A reduction in SNR in the liver similar to that obtained with SHU555A could be obtained by increasing the dose of CSIC, which has a weaker T2-shortening effect. In the TSE sequence with a weaker susceptibility effect, the decrease in SNR in the liver tended to be equalized to those in the CSE or TGSE sequences by high dose administration of the iron colloid preparation. We think perhaps that the imaging ability for hepatocellular carcinoma, similar to that of superparamagnetic contrast media, can be obtained with paramagnetic CSIC by administering it at a higher dose. (author)

  8. Reticuloendothelial negative contrast media for hepatocellular carcinoma. Initial comparison of chondroitin sulfate iron colloid and Ferrixan in fast T2-weighted MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sugihara, Shuji; Suto, Yuji; Kamba, Masayuki; Yoshida, Kotaro [Tottori Univ., Yonago (Japan). Faculty of Medicine

    1996-11-01

    Chondroitin sulfate iron colloid (CSIC), a paramagnetic substance, and Ferrixan (SHU555A), a superparamagnetic substance, were administered to 20 patients with 26 nodules of hepatocellular carcinoma, and the visualization of the lesions by fast T2-weighted magnetic resonance imaging (MRI) was quantitatively evaluated. Conventional spin-echo (CSE), turbo spin-echo (TSE), and turbo gradient spin-echo (TGSE) sequences were performed in all patients before and after the administration of the iron colloid preparations. The signal-to-noise ratio (SNR) in the liver decreased significantly after administration of iron colloid preparations by all sequences and at all doses. A reduction in SNR in the liver similar to that obtained with SHU555A could be obtained by increasing the dose of CSIC, which has a weaker T2-shortening effect. In the TSE sequence with a weaker susceptibility effect, the decrease in SNR in the liver tended to be equalized to those in the CSE or TGSE sequences by high dose administration of the iron colloid preparation. We think perhaps that the imaging ability for hepatocellular carcinoma, similar to that of superparamagnetic contrast media, can be obtained with paramagnetic CSIC by administering it at a higher dose. (author)

  9. The application value of diffusion-weighted magnetic resonance imaging in gross tumor volume delineation of esophageal squamous cell carcinoma

    International Nuclear Information System (INIS)

    Hou Dongliang; Shi Gaofeng; Gao Xianshu

    2012-01-01

    Objective: To analyze the application value of diffusion-weighted magnetic resonance imaging (DWMRI) in gross tumor volume (GTV) delineation of esophageal squamous cell carcinoma (SCC). Methods: Twenty-nine patients with esophageal SCC treated with radical surgery were analyzed. Routine CT scan, MRI T 2 -weighted and DWMRI were employed before surgery; diffusion-sensitive gradient b-values were taken 400, 600 and 800 s/mm 2 . GTVs were delineated using CT, MRI T 2 -weighted images and DWMRI under different b-value images. The length of GTVs measured under different images was compared with the pathological length and confirm the most accurate imaging condition. Use radiotherapy planning system to fuse DWMRI images and CT images to investigate the possibility of delineate GTVs on fused images. Results: The difference of GTV length value between CT, T 2 WI images and specimen was 3.36 mm and 2.84 mm. When b =400,600 and 800 s/mm 2 , the difference between GTV length value on the DWMRI images and on specimen was 0.47 mm, -0.47 mm and - 1.53 mm; the correlation coefficient of the measuring esophageal lengths on DWMRI images and the pathological lengths was 0.928, 0.927 and 0.938. DWMRI images and CT images could fuse accurately on radiotherapy planning system. GTV margin could.show clearly on fused images. Conclusions: DWMRI images can display the esophageal carcinoma lengths and margin accurately. When DWMRI images fused with CT images, GTV margin could show clearly,it can be used to delineate GTV accurately. (authors)

  10. Magnetic resonance imaging of intervertebral disc degeneration

    International Nuclear Information System (INIS)

    Maeda, Hiroshi; Noguchi, Masao; Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi.

    1993-01-01

    The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.)

  11. Magnetic resonance imaging of intervertebral disc degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Hiroshi; Noguchi, Masao (Kitakyushu City Yahata Hospital, Fukuoka (Japan)); Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi

    1993-02-01

    The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.).

  12. Evaluation of iron colloid-enhanced T{sub 2}-weighted fast MR imaging of hepatocellular carcinoma. Comparison of SE, TSE and TGSE sequences

    Energy Technology Data Exchange (ETDEWEB)

    Sugihara, Shuji; Suto, Yuji; Kamba, Masayuki; Yoshida, Kotarou; Ohta, Yoshio [Tottori Univ., Yonago (Japan). Faculty of Medicine

    1996-06-01

    We have applied chondroitin sulfate iron colloid (CSIC) as a contrast agent for MRI in detecting hepatocellular carcinoma (HCC) on conventional spin-echo sequences (SE). In this report, we evaluated CSIC-enhanced T{sub 2}-weighted fast MR imaging of HCC. MR imaging were performed before and after i.v. administration of CSIC in 15 patients with 46 HCCs. T{sub 2}-weighted SE (1800/80/2, 210 x 256 matrix), T{sub 2}-weighted turbo spin-echo (TSE1800) (1800/90/5, echo train length=7, 252 x 256 matrix), TSE (3500/90/5, echo train length=7, 252 x 256 matrix) (TSE7), TSE (3500/99/5, echo train length=11, 242 x 256 matrix) (TSE11) and T{sub 2}-weighted turbo-gradient spine-echo (TGSE) (4500/108/4, echo train length=33, 252 x 256 matrix) images were compared quantitatively and qualitatively. In all sequences, liver signal-to-noise ratio (SNR) was significantly decreased and lesion-to-liver contrast-to-noise ratio (CNR) was significantly increased after CSIC administration. Although decreased ratio in liver and tumor SNR caused by CSIC was smaller on TSE sequences compared with SE and TGSE, increased ratio in lesion-to-liver CNR was largest on TSE7. Either before or after i.v. administration of CSIC, the number of detectable lesions was largest on TSE7. TSE with used longer TR, TE and decreased echo factor was useful method for CSIC-enhanced abdominal MR imaging. (author)

  13. Relative signal intensity changes of frontal and occipital white matters on T 2 weighted axial MR image : correlation with age

    International Nuclear Information System (INIS)

    Kim, You Me; Kim, Seung Cheol

    1998-01-01

    The purpose of this study is to assess relative signal intensity changes in frontal and occipital white matter with age, as seen on T 2 weighted axial MR images. Thirty eight normal adults (20-29 years old) and 114 children (0-11 years old) were investigated. All had nonspecific neurologic symptoms and their MR images, obtained using a 1.5 T system (Signa, GE Medical Systems, Milwaukee, U.S.A.), appeared to be normal. The signal intensities of frontal and occipital white matter were evaluated on T2 weighted axial images at the level of the foramen of Monro. When the signal intensity of white matter was higher than that of gray matter, grade 0 was assigned; when the opposite situation pertained, this was graded I - III. Grade I indicated that the signal intensity of occipital white matter was lower than that of frontal white matter; grade II, that the signal intensity of white matter of both lobes was similar. When the signal intensity of frontal white matter was lower than that of occipital age, and by one year after 2 years of age, and then determined grade according to age, age distribution according to grade, and the ages at which signal intensities were similar to those of adults. On T2-weighted MR images, the signal intensity of frontal white matter ultimately shows a lower signal intensity than that of occipital white matter. (author). 11 refs., 6 figs

  14. Post-contrast T1-weighted sequences in pediatric abdominal imaging: comparative analysis of three different sequences and imaging approach

    Energy Technology Data Exchange (ETDEWEB)

    Roque, Andreia; Ramalho, Miguel; AlObaidy, Mamdoh; Heredia, Vasco; Burke, Lauren M.; De Campos, Rafael O.P.; Semelka, Richard C. [University of North Carolina at Chapel Hill, Department of Radiology, Chapel Hill, NC (United States)

    2014-10-15

    Post-contrast T1-weighted imaging is an essential component of a comprehensive pediatric abdominopelvic MR examination. However, consistent good image quality is challenging, as respiratory motion in sedated children can substantially degrade the image quality. To compare the image quality of three different post-contrast T1-weighted imaging techniques - standard three-dimensional gradient-echo (3-D-GRE), magnetization-prepared gradient-recall echo (MP-GRE) and 3-D-GRE with radial data sampling (radial 3-D-GRE) - acquired in pediatric patients younger than 5 years of age. Sixty consecutive exams performed in 51 patients (23 females, 28 males; mean age 2.5 ± 1.4 years) constituted the final study population. Thirty-nine scans were performed at 3 T and 21 scans were performed at 1.5 T. Two different reviewers independently and blindly qualitatively evaluated all sequences to determine image quality and extent of artifacts. MP-GRE and radial 3-D-GRE sequences had the least respiratory motion (P < 0.0001). Standard 3-D-GRE sequences displayed the lowest average score ratings in hepatic and pancreatic edge definition, hepatic vessel clarity and overall image quality. Radial 3-D-GRE sequences showed the highest scores ratings in overall image quality. Our preliminary results support the preference of fat-suppressed radial 3-D-GRE as the best post-contrast T1-weighted imaging approach for patients under the age of 5 years, when dynamic imaging is not essential. (orig.)

  15. Characterizing the microstructural basis of “unidentified bright objects” in neurofibromatosis type 1 : A combined in vivo multicomponent T2 relaxation and multi-shell diffusion MRI analysis

    NARCIS (Netherlands)

    Billiet, T.; Mädler, B.; D'Arco, F.; Deprez, S.; Plasschaert, E.; Leemans, A.; Zhang, H.; Van Den Bergh, B.R.H.; Vandenbulcke, M.; Legius, E.; Sunaert, S.; Emsell, L.

    2014-01-01

    Introduction The histopathological basis of “unidentified bright objects” (UBOs) (hyperintense regions seen on T2-weighted magnetic resonance (MR) brain scans in neurofibromatosis-1 (NF1)) remains unclear. New in vivo MRI-based techniques (multi-exponential T2 relaxation (MET2) and diffusion MR

  16. Is There an Additional Value of 11C-Choline PET-CT to T2-weighted MRI Images in the Localization of Intraprostatic Tumor Nodules?

    International Nuclear Information System (INIS)

    Van den Bergh, Laura; Koole, Michel; Isebaert, Sofie; Joniau, Steven; Deroose, Christophe M.; Oyen, Raymond; Lerut, Evelyne; Budiharto, Tom; Mottaghy, Felix; Bormans, Guy; Van Poppel, Hendrik; Haustermans, Karin

    2012-01-01

    Purpose: To investigate the additional value of 11 C-choline positron emission tomography (PET)-computed tomography (CT) to T2-weighted (T2w) magnetic resonance imaging (MRI) for localization of intraprostatic tumor nodules. Methods and Materials: Forty-nine prostate cancer patients underwent T2w MRI and 11 C-choline PET-CT before radical prostatectomy and extended lymphadenectomy. Tumor regions were outlined on the whole-mount histopathology sections and on the T2w MR images. Tumor localization was recorded in the basal, middle, and apical part of the prostate by means of an octant grid. To analyze 11 C-choline PET-CT images, the same grid was used to calculate the standardized uptake values (SUV) per octant, after rigid registration with the T2w MR images for anatomic reference. Results: In total, 1,176 octants were analyzed. Sensitivity, specificity, and accuracy of T2w MRI were 33.5%, 94.6%, and 70.2%, respectively. For 11 C-choline PET-CT, the mean SUV max of malignant octants was significantly higher than the mean SUV max of benign octants (3.69 ± 1.29 vs. 3.06 ± 0.97, p mean values (2.39 ± 0.77 vs. 1.94 ± 0.61, p mean and absolute tumor volume (Spearman r = 0.3003, p = 0.0362). No correlation was found between SUVs and prostate-specific antigen, T-stage or Gleason score. The highest accuracy (61.1%) was obtained with a SUV max cutoff of 2.70, resulting in a sensitivity of 77.4% and a specificity of 44.9%. When both modalities were combined (PET-CT or MRI positive), sensitivity levels increased as a function of SUV max but at the cost of specificity. When only considering suspect octants on 11 C-choline PET-CT (SUV max ≥ 2.70) and T2w MRI, 84.7% of these segments were in agreement with the gold standard, compared with 80.5% for T2w MRI alone. Conclusions: The additional value of 11 C-choline PET-CT next to T2w MRI in detecting tumor nodules within the prostate is limited.

  17. Properties of a magnetic superconductor with weak magnetization-application to ErNi2B2C

    International Nuclear Information System (INIS)

    Ng, T.K.; Leung, W.T.

    2001-01-01

    Using a Ginsburg-Landau free-energy functional, we study the H-T phase diagram of a weak magnetic superconductor, where the magnetization from the magnetic component is marginal in supporting a spontaneous vortex phase. In particular, the competition between the spiral state and spontaneous vortex phase is analysed. Our theory is applied to understand the magnetic properties of ErNi 2 B 2 C. (orig.)

  18. The (x, T) magnetic phase diagram of Y2Co17-xCrx (1.17-bar x-bar 3) compounds by neutron diffraction

    International Nuclear Information System (INIS)

    Schobinger-Papamantellos, P.; Buschow, K.H.J.; Fuquan, B.; Tegus, O.; Brueck, E.; Boer, F.R. de; Ritter, C.

    2006-01-01

    We present the (x, T) phase diagram of the ferromagnetic Y 2 Co 17-x Cr x (x=1.17, 1.76, 2.34, 3) compounds with rhombohedral structure (space group R3-bar m, Th 2 Zn 17 -type), determined for the entire magnetically ordered regime from high-resolution neutron-diffraction data. Substitution of small amounts of Cr for Co was found to have drastic effects on the magnetic properties such as a decrease of the Curie (T C ) and spin reorientation (T SR ) temperatures as well as a decrease of the ordered-moment values. These effects could be brought into connection to the fact that Cr was found to have a preference for the four Co sites in the following order 6c>18f>9d>18h. The number of Cr atoms found occupying the latter two sites, however, is within experimental error negligible. The magnetic phase diagram comprises three distinct regions of magnetic order in addition to the paramagnetic state: (a) the HT range (easy axis) (b) the LT (easy plane) for 0 C and T SR . It also leads to the formation of varying portions of the hexagonal Th 2 Ni 17 -modification (with similar magnetic properties) in samples with x>=1.76. The crystal and magnetic structure of both modifications were refined simultaneously

  19. Electrostatic and magnetic measurements of turbulence and transport in Extrap T2

    International Nuclear Information System (INIS)

    Moeller, A.; Sallander, E.

    1999-01-01

    Langmuir probe and magnetic pick-up coil measurements are used to study edge turbulence in the Extrap T2 reversed field pinch. Magnetic fluctuations resonant outside the toroidal field reversal surface are observed where previously only fluctuations in the spectra of potential and electron density and temperature have been measured. Results are presented which imply that these fluctuations are coupled to and also correlated to the internally resonant tearing mode fluctuations. Evidence of coupling between low-frequency (<100 kHz) and high-frequency fluctuations is also presented. The normalized floating potential fluctuations are seen to increase with the edge electron temperature. This causes an increase of the potential and density fluctuation driven transport with the temperature which is faster than linear. These results, in combination, are consistent with a picture where internally resonant fluctuations couple to edge fluctuations through radial heat conduction from the stochastic core to the edge. (author)

  20. Electrostatic and magnetic measurements of turbulence and transport in Extrap T2

    Science.gov (United States)

    Möller, Anders; Sallander, Eva

    1999-10-01

    Langmuir probe and magnetic pick-up coil measurements are used to study edge turbulence in the Extrap T2 reversed field pinch. Magnetic fluctuations resonant outside the toroidal field reversal surface are observed where previously only fluctuations in the spectra of potential and electron density and temperature have been measured. Results are presented which imply that these fluctuations are coupled to and also correlated to the internally resonant tearing mode fluctuations. Evidence of coupling between low-frequency (<100 kHz) and high-frequency fluctuations is also presented. The normalized floating potential fluctuations are seen to increase with the edge electron temperature. This causes an increase of the potential and density fluctuation driven transport with the temperature which is faster than linear. These results, in combination, are consistent with a picture where internally resonant fluctuations couple to edge fluctuations through radial heat conduction from the stochastic core to the edge.

  1. T2 Relaxation Time Mapping of Proximal Tibiofibular Cartilage by 3-Tesla Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Kwack, Kyu-Sung; Cho, Jae Hyun; Kim, Jun Man; Kim, Sun Yong; Min, Byoung-Hyun; Yoon, Seung-Hyun

    2009-01-01

    Background: The proximal tibiofibular joint (PTFJ) can be considered the fourth compartment of the knee joint. However, there have been no studies of the T2 values (T2 relaxation time) of PTFJ cartilage. Purpose: To assess the T2 values of PTFJ cartilage at 3T magnetic resonance imaging (MRI), and to show the clinical utility of T2 values of PTFJ cartilage for the diagnosis of osteoarthritis (OA). Material and Methods: 118 patients who had knee MR imaging and knee radiography were enrolled. MRI was performed using a 3T MRI scanner, and T2 maps were calculated from a sagittal multi-echo acquisition. Two regions of interest (ROIs) were positioned within PTFJ cartilage and medial femoral condyle (MFC) cartilage. The average T2 value and standard deviation (SD) of each ROI were recorded. Using PTFJ cartilage as a standard reference, the T2 index ((MFC/PTFJ)x100) and T2SD index ((MFCSD/PTFJSD)x100) were calculated. A paired t test was performed to compare the mean and SD of ROIs within PTFJ and MFC cartilage. Correlation analyses were performed among the parameters age, Kellgren-Lawrence (KL) score, means and SDs of ROIs within PTFJ and MFC cartilage, T2 index, and T2SD index. Results: PTFJ cartilage had a significantly shorter T2 value than did MFC cartilage (P<0.0001). ROIs within PTFJ cartilage showed significantly smaller SDs than did those within MFC cartilage (P<0.0001). The average T2 value and SD of MFC and the T2SD index showed a positive correlation to the KL score (P<0.05). The correlation coefficients for the average T2 value, SD, and T2SD index of MFC were R=0.203, 0.254, and 0.268, respectively. However, there was no significant correlation between T2 values of PTFJ cartilage and KL score (P=0.643). Conclusion: PTFJ cartilage showed shorter and more homogeneous T2 values with a small SD than did MFC cartilage, regardless of the degree of OA at femorotibial compartments. PTFJ cartilage may be a useful internal standard reference to diagnose OA and would be

  2. T2 Relaxation Time Mapping of Proximal Tibiofibular Cartilage by 3-Tesla Magnetic Resonance Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kwack, Kyu-Sung; Cho, Jae Hyun; Kim, Jun Man; Kim, Sun Yong (Dept. of Radiology, Ajou Univ. Medical Center, Suwon (Korea)); Min, Byoung-Hyun; Yoon, Seung-Hyun (Cartilage Regeneration Center, Ajou Univ. Medical Center, Suwon (Korea))

    2009-11-15

    Background: The proximal tibiofibular joint (PTFJ) can be considered the fourth compartment of the knee joint. However, there have been no studies of the T2 values (T2 relaxation time) of PTFJ cartilage. Purpose: To assess the T2 values of PTFJ cartilage at 3T magnetic resonance imaging (MRI), and to show the clinical utility of T2 values of PTFJ cartilage for the diagnosis of osteoarthritis (OA). Material and Methods: 118 patients who had knee MR imaging and knee radiography were enrolled. MRI was performed using a 3T MRI scanner, and T2 maps were calculated from a sagittal multi-echo acquisition. Two regions of interest (ROIs) were positioned within PTFJ cartilage and medial femoral condyle (MFC) cartilage. The average T2 value and standard deviation (SD) of each ROI were recorded. Using PTFJ cartilage as a standard reference, the T2 index ((MFC/PTFJ)x100) and T2SD index ((MFCSD/PTFJSD)x100) were calculated. A paired t test was performed to compare the mean and SD of ROIs within PTFJ and MFC cartilage. Correlation analyses were performed among the parameters age, Kellgren-Lawrence (KL) score, means and SDs of ROIs within PTFJ and MFC cartilage, T2 index, and T2SD index. Results: PTFJ cartilage had a significantly shorter T2 value than did MFC cartilage (P<0.0001). ROIs within PTFJ cartilage showed significantly smaller SDs than did those within MFC cartilage (P<0.0001). The average T2 value and SD of MFC and the T2SD index showed a positive correlation to the KL score (P<0.05). The correlation coefficients for the average T2 value, SD, and T2SD index of MFC were R=0.203, 0.254, and 0.268, respectively. However, there was no significant correlation between T2 values of PTFJ cartilage and KL score (P=0.643). Conclusion: PTFJ cartilage showed shorter and more homogeneous T2 values with a small SD than did MFC cartilage, regardless of the degree of OA at femorotibial compartments. PTFJ cartilage may be a useful internal standard reference to diagnose OA and would be

  3. Magnetic resonance imaging findings in patients with Hallervorden-Spatz syndrome

    International Nuclear Information System (INIS)

    Nomura, Cesar Higa; Lima, Eduardo Carneiro; Cerri, Giovanni Guido; Leite, Claudia da Costa; Rosemberg, Sergio

    2003-01-01

    The objective of this study was to review the magnetic resonance imaging findings in patients with Hallervorden-Spatz syndrome. We evaluated eight patients with Hallervorden-Spatz syndrome using magnetic resonance imaging. The protocol included at least sagittal and axial T1-weighted images and axial and coronal T2-weighted images. Intravenous gadolinium was administered in a dose of 0.1 mmol/kg. Post-enhanced images were obtained at least in the axial and coronal planes. The results were: all patients presented a bilateral and symmetrical 'tiger-eye signal' on T2-weighted images, corresponding to central hyperintensity and peripheral hypointensity in the globi pallidus. FLAIR and diffusion images showed similar abnormalities. There was no gadolinium enhancement in any of the cases. We concluded that magnetic resonance imaging findings in patients with Hallervorden-Spatz syndrome are very typical and allow the diagnosis of the disease. (author)

  4. Significance of high-intensity signals on cranial MRI T2 weighted image in diagnosis of age-associated dementia. From a viewpoint of reversibility of brain function

    International Nuclear Information System (INIS)

    Kishiro, Masaki

    1994-01-01

    This study was undertaken to determine whether changes of EEG band profile in patients showing high-intensity signal (HIS) on cranial magnetic resonance images (MRI), who had however no vascular lesions on cranial CT, were similar to those in multi-infarct dementia (MID) or senile dementia of Alzheimer type (SDAT) patients and to determine the significance of HIS in the diagnosis of SDAT. Forty-two patients with dementia diagnosed according to DSM-III-R were divided into HIS (n=21), MID (n=13), and SDAT (n=8) based on CT and MRI findings. Multi-infarcted lesions were seen on cranial CT and HIS was seen on cranial MRI in MID patients. There were no abnormal lesions except brain atrophy on cranial CT and MRI in SDAT patients. Appearance rates (%) of the 2-18 c/s frequency bands using computerized quantitative EEG before and after administration of protirelin tartrate (TRH-T) were analyzed in the frontal, central, parietal and occipital areas of the brain. There were no significant differences in appearance rates of EEG frequency bands before administration of TRH-T in HIS, MID, and SDAT patients. A significant decrease in appearance rates of slow waves and a significant increase in appearance rates of α waves were observed after administration of TRH-T in the four areas in MID patients compared with those before administration. No significant differences in appearance rates of EEG frequency bands were observed after administration of TRH-T in the four areas in HIS and SDAT patients compared with those before administration. Changes of the EEG band profile in HIS patients were similar to those in SDAT patients. In the presence of appearance of HSI on cranial MRI T 2 weighted images, the possibility of SDAT patients cannot be excluded. Therefore, SDAT should be diagnosed based on both clinical data and the absence of brain vascular lesions on cranial CT. Also, HIS on MRI T 2 -weighted images is considered to reflect non-vascular lesions. (J.N.P.)

  5. Prospective comparison of T2w-MRI and dynamic-contrast-enhanced MRI, 3D-MR spectroscopic imaging or diffusion-weighted MRI in repeat TRUS-guided biopsies

    Energy Technology Data Exchange (ETDEWEB)

    Portalez, Daniel [Clinique Pasteur, 45, Department of Radiology, Toulouse (France); Rollin, Gautier; Mouly, Patrick; Jonca, Frederic; Malavaud, Bernard [Hopital de Rangueil, Department of Urology, Toulouse Cedex 9 (France); Leandri, Pierre [Clinique Saint Jean, 20, Department of Urology, Toulouse (France); Elman, Benjamin [Clinique Pasteur, 45, Department of Urology, Toulouse (France)

    2010-12-15

    To compare T2-weighted MRI and functional MRI techniques in guiding repeat prostate biopsies. Sixty-eight patients with a history of negative biopsies, negative digital rectal examination and elevated PSA were imaged before repeat biopsies. Dichotomous criteria were used with visual validation of T2-weighted MRI, dynamic contrast-enhanced MRI and literature-derived cut-offs for 3D-spectroscopy MRI (choline-creatine-to-citrate ratio >0.86) and diffusion-weighted imaging (ADC x 10{sup 3} mm{sup 2}/s < 1.24). For each segment and MRI technique, results were rendered as being suspicious/non-suspicious for malignancy. Sextant biopsies, transition zone biopsies and at least two additional biopsies of suspicious areas were taken. In the peripheral zones, 105/408 segments and in the transition zones 19/136 segments were suspicious according to at least one MRI technique. A total of 28/68 (41.2%) patients were found to have cancer. Diffusion-weighted imaging exhibited the highest positive predictive value (0.52) compared with T2-weighted MRI (0.29), dynamic contrast-enhanced MRI (0.33) and 3D-spectroscopy MRI (0.25). Logistic regression showed the probability of cancer in a segment increasing 12-fold when T2-weighted and diffusion-weighted imaging MRI were both suspicious (63.4%) compared with both being non-suspicious (5.2%). The proposed system of analysis and reporting could prove clinically relevant in the decision whether to repeat targeted biopsies. (orig.)

  6. Magnetic resonance imaging of canine degenerative lumbar spine diseases

    International Nuclear Information System (INIS)

    Karkkainen, M.; Punto, L.U.; Tulamo, R.M.

    1993-01-01

    Degenerative lumbar spine diseases, i.e., sacrolumbar stenosis, intervertebral disk degeneration and protrusion and spondylosis deformans of the canine lumbar spine were studied in eleven canine patients and three healthy controls using radiography and 0.02 T and 0.04 T low field magnetic resonance imaging. The T1 and T2 weighted images were obtained in sagittal and transverse planes. The loss of hydration of nucleus pulposus, taken as a sign of degeneration in the intervertebral disks, could be evaluated in both T1 and T2 weighted images. As a noninvasive method magnetic resonance imaging gave more exact information about the condition of intervertebral disks than did radiography. Sacrolumbar stenosis and compression of the spinal cord or cauda equina and surrounding tissue could be evaluated without contrast medium

  7. Direct evidence of Ni magnetic moment in TbNi{sub 2}Mn—X-ray magnetic circular dichroism

    Energy Technology Data Exchange (ETDEWEB)

    Yu, D.H., E-mail: dyu@ansto.gov.au [Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, NSW 2234 (Australia); Huang, Meng-Jie [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Wang, J.L. [Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, NSW 2234 (Australia); School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Canberra at the Australian Defense Force Academy, Sydney, ACT 2600 (Australia); Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia); Su, Hui-Chia; Lin, Hong-Ji; Chen, Chien-Te [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Campbell, S.J. [School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Canberra at the Australian Defense Force Academy, Sydney, ACT 2600 (Australia)

    2014-12-15

    We have investigated the individual magnetic moments of Ni, Mn and Tb atoms in the intermetallic compound TbNi{sub 2}Mn in the Laves phase (magnetic phase transition temperature T{sub C} ∼131 K) by X-ray magnetic circular dichroism (XMCD) studies at 300 K, 80 K and 20 K. Analyses of the experimental results reveal that Ni atoms at 20 K in an applied magnetic field of 1 T carry an intrinsic magnetic moment of spin and orbital magnetic moment contributions 0.53±0.01 μ{sub B} and 0.05±0.01 μ{sub B}, respectively. These moment values are similar to those of the maximum saturated moment of Ni element. A very small magnetic moment of order <0.1 μ{sub B} has been measured for Mn. This suggests that Mn is antiferromagnetically ordered across the two nearly equally occupied sites of 16d and 8a. A magnetic moment of up to ∼0.3 μ{sub B} has been observed for the Tb atoms. Identification of a magnetic moment on the Ni atoms has provided further evidence for the mechanism of enhancement of the magnetic phase transition temperature in TbNi{sub 2}Mn compared with TbNi{sub 2} (T{sub C}∼37.5 K) and TbMn{sub 2} (T{sub C}∼54 K) due to rare earth–transition metal (R–T) and transition metal–transition metal (T–T) interactions. The behaviour of the X-ray magnetic circular dichroism spectra of TbNi{sub 2}Mn at 300 K, 80 K and 20 K – above and below the magnetic ordering temperature T{sub C} ∼131 K – is discussed. - Highlights: • We study the magnetic moment of TbNi{sub 2}Mn with XMCD. • We observe directly the Ni intrinsic magnetic moment in TbNi{sub 2}Mn. • We find that Mn ordered antiferromagnetically across the 16d and 8a sites. • We confirm the mechanism for increasing the magnetic phase transition temperature.

  8. Magnetic properties of PrMn2-xFexGe2-57Fe Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Wang, J L; Campbell, S J; Cadogan, J M; Tegus, O; Studer, A J; Hofmann, M

    2006-01-01

    We have investigated the magnetic behaviour of PrMn 2-x Fe x Ge 2 compounds with x = 0.4, 0.6 and 0.8 over the temperature range 4.2-350 K using ac magnetic susceptibility, dc magnetization and 57 Fe Moessbauer effect spectroscopy, as well as neutron diffraction for the PrMn 1.2 Fe 0.8 Ge 2 compound. Replacement of Mn with Fe leads to contraction of the unit cell and a shortening of the Mn-Mn spacing, resulting in modification of the magnetic structure. PrMn 1.6 Fe 0.4 Ge 2 is an intralayer antiferromagnet at room temperature and ferromagnetic below T C inter ∼230 K with additional ferromagnetic ordering of the Pr sublattice detected below T C Pr ∼30 K. Re-entrant ferromagnetism has been observed in PrMn 1.4 Fe 0.6 Ge 2 with four magnetic transitions (T N intra ∼333 K, T C inter ∼168 K, T N inter ∼152 K and T C Pr ∼40 K). Moreover, it was found that T C inter and T C Pr increase with applied field while T N inter decreases. PrMn 1.2 Fe 0.8 Ge 2 is antiferromagnetic with T N intra ∼242 K and T N inter ∼154 K. The magnetic transition temperatures for all compounds are also marked by changes in the 57 Fe magnetic hyperfine field and the electric quadrupole interaction parameters. The 57 Fe transferred hyperfine field at 4.5 K in PrMn 1.6 Fe 0.4 Ge 2 and PrMn 1.4 Fe 0.6 Ge 2 is reduced (below the ordering temperature of the Pr sublattice) compared with that at 80 K (above T C Pr ), indicating that the transferred hyperfine field from Pr acts in the opposite direction to that from the Mn atoms. The neutron data for PrMn 1.2 Fe 0.8 Ge 2 demonstrate that an anisotropic thermal expansion occurs within the interplanar antiferromagnetic range

  9. Diffusion weighted magnetic resonance imaging: ischemic and traumatic injury of the central nervous system

    International Nuclear Information System (INIS)

    Huisman, T.A.G.M.; Sorensen, A.G.; Hawighorst, H.; Benoit, C.H.

    2001-01-01

    Diffusion weighted magnetic resonance imaging (DWI) represents a recent development that extends imaging from the depiction of the neuroanatomy into the field of functional and physiologic processes. DWI measures a fundamentally different physiologic parameter than conventional MRI. Image contrast is related to differences in the microscopic motion (diffusion) of water molecules within brain tissue rather than a change in total tissue water. Consequently, DWI can reveal pathology where conventional T1- and T2-weighted MR images are negative. DWI has clinically proven its value in the assessment of acute cerebral stroke and trauma by showing cerebral injury early due to its ability to discriminate between lesions with cytotoxic edema (decreased diffusion) from lesions with vasogenic edema (increased diffusion). Full tensor DWI allows to calculate a variety of functional maps, the most widely used maps include maps of apparent diffusion coefficients and isotropic diffusion. In addition maps of anisotropic diffusion can be calculated which are believed to give information about the integrity and location of fiber tracts. This functional-anatomical information will most probably play an increasingly important role in the early detection of primary and secondary tissue injury from various reasons and could guide and validate current and future neuroprotective treatments. (orig.) [de

  10. Effectiveness of a Rapid Lumbar Spine MRI Protocol Using 3D T2-Weighted SPACE Imaging Versus a Standard Protocol for Evaluation of Degenerative Changes of the Lumbar Spine.

    Science.gov (United States)

    Sayah, Anousheh; Jay, Ann K; Toaff, Jacob S; Makariou, Erini V; Berkowitz, Frank

    2016-09-01

    Reducing lumbar spine MRI scanning time while retaining diagnostic accuracy can benefit patients and reduce health care costs. This study compares the effectiveness of a rapid lumbar MRI protocol using 3D T2-weighted sampling perfection with application-optimized contrast with different flip-angle evolutions (SPACE) sequences with a standard MRI protocol for evaluation of lumbar spondylosis. Two hundred fifty consecutive unenhanced lumbar MRI examinations performed at 1.5 T were retrospectively reviewed. Full, rapid, and complete versions of each examination were interpreted for spondylotic changes at each lumbar level, including herniations and neural compromise. The full examination consisted of sagittal T1-weighted, T2-weighted turbo spin-echo (TSE), and STIR sequences; and axial T1- and T2-weighted TSE sequences (time, 18 minutes 40 seconds). The rapid examination consisted of sagittal T1- and T2-weighted SPACE sequences, with axial SPACE reformations (time, 8 minutes 46 seconds). The complete examination consisted of the full examination plus the T2-weighted SPACE sequence. Sensitivities and specificities of the full and rapid examinations were calculated using the complete study as the reference standard. The rapid and full studies had sensitivities of 76.0% and 69.3%, with specificities of 97.2% and 97.9%, respectively, for all degenerative processes. Rapid and full sensitivities were 68.7% and 66.3% for disk herniation, 85.2% and 81.5% for canal compromise, 82.9% and 69.1% for lateral recess compromise, and 76.9% and 69.7% for foraminal compromise, respectively. Isotropic SPACE T2-weighted imaging provides high-quality imaging of lumbar spondylosis, with multiplanar reformatting capability. Our SPACE-based rapid protocol had sensitivities and specificities for herniations and neural compromise comparable to those of the protocol without SPACE. This protocol fits within a 15-minute slot, potentially reducing costs and discomfort for a large subgroup of

  11. Independent value of image fusion in unenhanced breast MRI using diffusion-weighted and morphological T2-weighted images for lesion characterization in patients with recently detected BI-RADS 4/5 X-ray mammography findings

    Energy Technology Data Exchange (ETDEWEB)

    Bickelhaupt, Sebastian; Tesdorff, Jana; Delorme, Stefan; Schlemmer, Heinz-Peter [German Cancer Research Center (dkfz), Department of Radiology, Heidelberg (Germany); Laun, Frederik Bernd; Kuder, Tristan Anselm [German Cancer Research Center (dkfz), Medical Physics in Radiology, Heidelberg (Germany); Lederer, Wolfgang; Teiner, Susanne [Radiological Practice at the ATOS Clinic Heidelberg, Heidelberg (Germany); Maier-Hein, Klaus [German Cancer Research Center (dkfz), Junior Group Medical Image Computing, Heidelberg (Germany); Daniel, Heidi [Radiology Center Mannheim (RZM), Mannheim (Germany); Stieber, Anne [University Hospital Heidelberg, Department of Clinical and Interventional Radiology, Heidelberg (Germany)

    2017-02-15

    The aim of this study was to evaluate the accuracy and applicability of solitarily reading fused image series of T2-weighted and high-b-value diffusion-weighted sequences for lesion characterization as compared to sequential or combined image analysis of these unenhanced sequences and to contrast- enhanced breast MRI. This IRB-approved study included 50 female participants with suspicious breast lesions detected in screening X-ray mammograms, all of which provided written informed consent. Prior to biopsy, all women underwent MRI including diffusion-weighted imaging (DWIBS, b = 1500s/mm{sup 2}). Images were analyzed as follows: prospective image fusion of DWIBS and T2-weighted images (FU), side-by-side analysis of DWIBS and T2-weighted series (CO), combination of the first two methods (CO+FU), and full contrast-enhanced diagnostic protocol (FDP). Diagnostic indices, confidence, and image quality of the protocols were compared by two blinded readers. Reading the CO+FU (accuracy 0.92; NPV 96.1 %; PPV 87.6 %) and the CO series (0.90; 96.1 %; 83.7 %) provided a diagnostic performance similar to the FDP (0.95; 96.1 %; 91.3 %; p > 0.05). FU reading alone significantly reduced the diagnostic accuracy (0.82; 93.3 %; 73.4 %; p = 0.023). MR evaluation of suspicious BI-RADS 4 and 5 lesions detected on mammography by using a non-contrast-enhanced T2-weighted and DWIBS sequence protocol is most accurate if MR images were read using the CO+FU protocol. (orig.)

  12. Phosphorus magnetic resonance spectroscopic imaging at 7 T in patients with prostate cancer.

    Science.gov (United States)

    Lagemaat, Miriam W; Vos, Eline K; Maas, Marnix C; Bitz, Andreas K; Orzada, Stephan; van Uden, Mark J; Kobus, Thiele; Heerschap, Arend; Scheenen, Tom W J

    2014-05-01

    The aim of this study was to identify characteristics of phosphorus (P) spectra of the human prostate and to investigate changes of individual phospholipid metabolites in prostate cancer through in vivo P magnetic resonance spectroscopic imaging (MRSI) at 7 T. In this institutional review board-approved study, 15 patients with biopsy-proven prostate cancer underwent T2-weighted magnetic resonance imaging and 3-dimensional P MRSI at 7 T. Voxels were selected at the tumor location, in normal-appearing peripheral zone tissue, normal-appearing transition zone tissue, and in the base of the prostate close to the seminal vesicles. Phosphorus metabolite ratios were determined and compared between tissue types. Signals of phosphoethanolamine (PE) and phosphocholine (PC) were present and well resolved in most P spectra in the prostate. Glycerophosphocholine signals were observable in 43% of the voxels in malignant tissue, but in only 10% of the voxels in normal-appearing tissue away from the seminal vesicles. In many spectra, independent of tissue type, 2 peaks resonated in the chemical shift range of inorganic phosphate, possibly representing 2 separate pH compartments. The PC/PE ratio in the seminal vesicles was highly elevated compared with the prostate in 5 patients. A considerable overlap of P metabolite ratios was found between prostate cancer and normal-appearing prostate tissue, preventing direct discrimination of these tissues. The only 2 patients with high Gleason scores tumors (≥4+5) presented with high PC and glycerophosphocholine levels in their cancer lesions. Phosphorus MRSI at 7 T shows distinct features of phospholipid metabolites in the prostate gland and its surrounding structures. In this exploratory study, no differences in P metabolite ratios were observed between prostate cancer and normal-appearing prostate tissue possibly because of the partial volume effects of small tumor foci in large MRSI voxels.

  13. Magnetic resonance spectroscopy of the canine brain at 3.0 T and 7.0 T.

    Science.gov (United States)

    Martin-Vaquero, Paula; da Costa, Ronaldo C; Echandi, Rita L; Sammet, Christina L; Knopp, Michael V; Sammet, Steffen

    2012-08-01

    The purpose of this study was to evaluate the feasibility of proton magnetic resonance spectroscopy (1H MRS) to study the concentration of metabolites in the brain of dogs at 3.0 and 7.0 T. Four healthy male beagles were scanned using 3.0 T and 7.0 T human magnetic resonance imaging (MRI) units. The results obtained showed that all dogs had excellent quality spectra for a small (1 cm3) and large (8 cm3) voxel at 3.0 T, whereas only 2 dogs had high quality spectra at 7.0 T due to insufficient water suppression. 1H MRS at 3.0 T appears to be a reliable method to study metabolite concentrations in the canine brain. The development of more advanced water suppression techniques is necessary to improve the results at 7.0 T. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Feasibility of similarity coefficient map for improving morphological evaluation of T2* weighted MRI for renal cancer

    International Nuclear Information System (INIS)

    Wang Hao-Yu; Bao Shang-Lian; Jiani Hu; Meng Li; Haacke, E. M.; Xie Yao-Qin; Chen Jie; Amy Yu; Wei Xin-Hua; Dai Yong-Ming

    2013-01-01

    The purpose of this paper is to investigate the feasibility of using a similarity coefficient map (SCM) in improving the morphological evaluation of T 2 * weighted (T 2 *W) magnatic resonance imaging (MRI) for renal cancer. Simulation studies and in vivo 12-echo T 2 *W experiments for renal cancers were performed for this purpose. The results of the first simulation study suggest that an SCM can reveal small structures which are hard to distinguish from the background tissue in T 2 *W images and the corresponding T 2 * map. The capability of improving the morphological evaluation is likely due to the improvement in the signal-to-noise ratio (SNR) and the carrier-to-noise ratio (CNR) by using the SCM technique. Compared with T 2 *W images, an SCM can improve the SNR by a factor ranging from 1.87 to 2.47. Compared with T 2 * maps, an SCM can improve the SNR by a factor ranging from 3.85 to 33.31. Compared with T 2 *W images, an SCM can improve the CNR by a factor ranging from 2.09 to 2.43. Compared with T 2 * maps, an SCM can improve the CNR by a factor ranging from 1.94 to 8.14. For a given noise level, the improvements of the SNR and the CNR depend mainly on the original SNRs and CNRs in T 2 *W images, respectively. In vivo experiments confirmed the results of the first simulation study. The results of the second simulation study suggest that more echoes are used to generate the SCM, and higher SNRs and CNRs can be achieved in SCMs. In conclusion, an SCM can provide improved morphological evaluation of T 2 *W MR images for renal cancer by unveiling fine structures which are ambiguous or invisible in the corresponding T 2 *W MR images and T 2 * maps. Furthermore, in practical applications, for a fixed total sampling time, one should increase the number of echoes as much as possible to achieve SCMs with better SNRs and CNRs

  15. Analysis of ischemic cerebral lesions using 3.0-T diffusion-weighted imaging and magnetic resonance angiography after revascularization surgery for ischemic disease.

    Science.gov (United States)

    Murai, Yasuo; Mizunari, Takayuki; Takagi, Ryo; Amano, Yasuo; Mizumura, Sunao; Komaba, Yuichi; Okubo, Seiji; Kobayashi, Shiro; Teramoto, Akira

    2013-07-01

    Cerebral revascularization surgery (CRS) is increasingly recognized as an important component in the treatment of complex cerebral vascular disease and tumors. CRS requires that the incidence of perioperative neurological complications should be minimized, because CRS for ischemic disease is often not the goal of treatment, but rather a prophylactic surgery. CRS carries the risk of focal postoperative neurological deficits. Little has been established concerning mechanisms of post-CRS ischemia. We used 3.0-T diffusion-weighted magnetic resonance imaging (DWI) and magnetic resonance angiography (MRA) to analyze the incidence and mechanism of ischemic lesions. We studied the anterior circulation territory after 20 CRS procedures involving 33 vascular anastomosis procedures (13 double anastomoses and 7 single anastomoses) in 12 men and 8 women between June 2007 and October 2011. The operations included single or double superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis to treat internal carotid artery/MCA occlusions or severe MCA stenosis. A combined STA-MCA anastomosis and indirect bypass were performed for moyamoya disease. Postoperative DWI and MRA were obtained in all patients between 24 and 96 h after surgery to detect thromboembolism, hypoperfusion, or procedural ischemic complications and vasospasms of the donor STA. Follow-up DWI and MRA were carried out 1.8±0.6 days after CRS (range, 1-4 days). Temporary occlusion time for anastomoses averaged 18.9 min (range, 16-32 min). Asymptomatic new hyperintensities occurred in the ipsilateral hemisphere of 2 patients on postoperative DWI (10% patients/6.0% anastomoses), and 1 moyamoya patient (5.0% patients/3.0% anastomoses) developed a symptomatic hyperintensity in the ipsilateral occipital lobe in response to the operation. Two abnormal small (3.0-T DWI study of CRS and related clinical events. The incidence of symptomatic postoperative DWI abnormalities was restricted to 1 moyamoya patient

  16. Conceptual designs of conduction cooled MgB2 magnets for 1.5 and 3.0T full body MRI systems

    Science.gov (United States)

    Baig, Tanvir; Al Amin, Abdullah; Deissler, Robert J; Sabri, Laith; Poole, Charles; Brown, Robert W; Tomsic, Michael; Doll, David; Rindfleisch, Matthew; Peng, Xuan; Mendris, Robert; Akkus, Ozan; Sumption, Michael; Martens, Michael

    2017-01-01

    Conceptual designs of 1.5 and 3.0 T full-body magnetic resonance imaging (MRI) magnets using conduction cooled MgB2 superconductor are presented. The sizes, locations, and number of turns in the eight coil bundles are determined using optimization methods that minimize the amount of superconducting wire and produce magnetic fields with an inhomogeneity of less than 10 ppm over a 45 cm diameter spherical volume. MgB2 superconducting wire is assessed in terms of the transport, thermal, and mechanical properties for these magnet designs. Careful calculations of the normal zone propagation velocity and minimum quench energies provide support for the necessity of active quench protection instead of passive protection for medium temperature superconductors such as MgB2. A new ‘active’ protection scheme for medium Tc based MRI magnets is presented and simulations demonstrate that the magnet can be protected. Recent progress on persistent joints for multifilamentary MgB2 wire is presented. Finite difference calculations of the quench propagation and temperature rise during a quench conclude that active intervention is needed to reduce the temperature rise in the coil bundles and prevent damage to the superconductor. Comprehensive multiphysics and multiscale analytical and finite element analysis of the mechanical stress and strain in the MgB2 wire and epoxy for these designs are presented for the first time. From mechanical and thermal analysis of our designs we conclude there would be no damage to such a magnet during the manufacturing or operating stages, and that the magnet would survive various quench scenarios. This comprehensive set of magnet design considerations and analyses demonstrate the overall viability of 1.5 and 3.0 T MgB2 magnet designs. PMID:29170604

  17. Identification of the primary motor cortex: value of T2 echo-planar imaging, diffusion-weighted imaging and quantitative apparent diffusion coefficient measurement at 3 T

    International Nuclear Information System (INIS)

    Dincer, Alp; Erzen, Canan; Oezyurt, Onur; Pamir, M.N.

    2010-01-01

    To investigate the primary motor cortex (PMC) concerning T2 shortening on T2 echo-planar imaging (EPI-T2) and the double-layer sign on diffusion-weighted imaging (DWI), and also to measure its apparent diffusion coefficient (ADC). 3-T MR DWI was performed in 134 adult volunteers and 64 patients. T2 shortening was graded as hypointense or isointense compared with the signal of the superior frontal cortex (SFC). The double-layer sign of the PMC was graded as present or absent. Both findings (T2 shortening and double-layer sign) were evaluated independently by two authors. ADC of the PMC and the SFC were calculated using manually selected ROIs. T2 shortening was found in 131 adults and 62 patients by author 1 and in 132 adults and 61 patients by author 2 (κ = 0.96 and 0.91). The double-layer sign was found in 131 adults and 61 patients by author 1 and in 127 adults and 58 patients by author 2 (κ = 0.94 and 0.91). ADC values of the PMC and the SFC were different for all subjects (p < 0.01). T2 shortening and/or the double-layer sign on 3-T MR can be used to locate the PMC. The difference in ADC values between PMC and SFC is a distinguishing feature. (orig.)

  18. High resolution T2 weighted liver MR imaging using functional residual capacity breath-hold with a 1.0-Tesla scanner

    International Nuclear Information System (INIS)

    Tabuchi, Akihiko; Katsuda, Toshizo; Gotanda, Rumi; Gotanda, Tatsuhiro; Mitani, Masahiko; Takeda, Yoshihiro

    2009-01-01

    Purpose: During acquisition of rapid high resolution (HR) T2 weighted (T2W) liver magnetic resonance (MR) images using a 1.0-Tesla (T) scanner, the liver is segmented into odd and even sections that are acquired at two different times using the multi-breath-hold (MBH) strategy. Misalignment between the two breath-hold (B-H) images may result in the occurrence of a blind area and a decrease in diagnostic accuracy. Here, a functional residual capacity (FRC) B-H method was developed to overcome this problem. Material and methods: Twenty-five volunteers were enrolled. The sagittal images were reconstructed from whole liver transverse images. When the B-H phases are different, misalignment may occur in the craniocaudal and anterior-posterior (AP) directions. In this study, misalignments of the abdominal wall were measured in the AP direction. The misalignment was compared between four B-H phases, maximum inspiration (MI), maximum expiration (ME), voluntary expiration (VE) and FRC using one-way repeated measures ANOVA. Differences between groups were compared using the t-test for multi-group comparisons. In addition, qualitative analysis of misalignment was performed between VE and FRC in 52 clinical patients and the χ 2 test was performed. Results: The misalignment widths of FRC, ME, MI and VE B-Hs were 2.7 ± 3.8, 6.4 ± 7.4, 9.1 ± 8.4 and 6.0 ± 6.7 mm, respectively. Misalignment of the liver position using FRC was significantly smaller than for the other B-H methods (p < 0.05). Significant differences between the VE B-H and FRC B-H were also observed in the qualitative analysis (p < 0.05). Conclusion: The liver positions obtained when using FRC B-H were significantly more reproducible than when using the other B-H methods. The FRC B-H method resulted in a reduction in the blind area and an extension of the diagnostic area to the whole liver.

  19. The application of T1 and T2 relaxation time and magnetization transfer ratios to the early diagnosis of patellar cartilage osteoarthritis

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Weiwu; Qu, Nan; Lu, Zhihua; Yang, Shixun [Shanghai Jiaotong University, Department of Radiology, Shanghai (China)

    2009-11-15

    We compare the T1 and T2 relaxation times and magnetization transfer ratios (MTRs) of normal subjects and patients with osteoarthritis (OA) to evaluate the ability of these techniques to aid in the early diagnosis and treatment of OA. The knee joints in 11 normal volunteers and 40 patients with OA were prospectively evaluated using T1 relaxation times as measured using delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), T2 relaxation times (multiple spin-echo sequence, T2 mapping), and MTRs. The OA patients were further categorized into mild, moderate, and severe OA. The mean T1 relaxation times of the four groups (normal, mild OA, moderate OA, and severe OA) were: 487.3{+-}27.7, 458.0{+-}55.9, 405.9{+-}57.3, and 357.9{+-}36.7 respectively (p<0.001). The mean T2 relaxation times of the four groups were: 37.8{+-}3.3, 44.0{+-}8.5, 50.9{+-}9.5, and 57.4{+-}4.8 respectively (p<0.001). T1 relaxation time decreased and T2 relaxation time increased with worsening degeneration of patellar cartilage. The result of the covariance analysis showed that the covariate age had a significant influence on T2 relaxation time (p<0.001). No significant differences between the normal and OA groups using MTR were noted. T1 and T2 relaxation times are relatively sensitive to early degenerative changes in the patellar cartilage, whereas the MTR may have some limitations with regard to early detection of OA. In addition, The T1 and T2 relaxation times negatively correlate with each other, which is a novel finding. (orig.)

  20. A simple method for detecting tumor in T2-weighted MRI brain images. An image-based analysis

    International Nuclear Information System (INIS)

    Lau, Phooi-Yee; Ozawa, Shinji

    2006-01-01

    The objective of this paper is to present a decision support system which uses a computer-based procedure to detect tumor blocks or lesions in digitized medical images. The authors developed a simple method with a low computation effort to detect tumors on T2-weighted Magnetic Resonance Imaging (MRI) brain images, focusing on the connection between the spatial pixel value and tumor properties from four different perspectives: cases having minuscule differences between two images using a fixed block-based method, tumor shape and size using the edge and binary images, tumor properties based on texture values using spatial pixel intensity distribution controlled by a global discriminate value, and the occurrence of content-specific tumor pixel for threshold images. Measurements of the following medical datasets were performed: different time interval images, and different brain disease images on single and multiple slice images. Experimental results have revealed that our proposed technique incurred an overall error smaller than those in other proposed methods. In particular, the proposed method allowed decrements of false alarm and missed alarm errors, which demonstrate the effectiveness of our proposed technique. In this paper, we also present a prototype system, known as PCB, to evaluate the performance of the proposed methods by actual experiments, comparing the detection accuracy and system performance. (author)

  1. Is there an added value of T1-weighted contrast-enhanced fat-suppressed spin-echo MR sequences compared to STIR sequences in MRI of the foot and ankle?

    Energy Technology Data Exchange (ETDEWEB)

    Zubler, Veronika; Zanetti, Marco; Dietrich, Tobias J.; Pfirrmann, Christian W.; Mamisch-Saupe, Nadja [University of Zurich, Faculty of Medicine, Zurich (Switzerland); Orthopedic University Hospital Balgrist, Department of Radiology, Zurich (Switzerland); Espinosa, Norman [University of Zurich, Faculty of Medicine, Zurich (Switzerland); Orthopedic University Hospital Balgrist, Orthopedic Surgery, Zurich (Switzerland)

    2017-08-15

    To prospectively compare T1-weighted fat-suppressed spin-echo magnetic resonance (MR) sequences after gadolinium application (T1wGdFS) to STIR sequences in patients with acute and chronic foot pain. In 51 patients referred for MRI of the foot and ankle, additional transverse and sagittal T1wGdFS sequences were obtained. Two sets of MR images (standard protocol with STIR or T1wGdFS) were analysed. Diagnosis, diagnostic confidence, and localization of the abnormality were noted. Standard of reference was established by an expert panel of two experienced MSK radiologists and one experienced foot surgeon based on MR images, clinical charts and surgical reports. Patients reported prospectively localization of pain. Descriptive statistics, McNemar test and Kappa test were used. Diagnostic accuracy with STIR protocol was 80% for reader 1, 67% for reader 2, with contrast-protocol 84%, both readers. Significance was found for reader 2. Diagnostic confidence for reader 1 was 1.7 with STIR, 1.3 with contrast-protocol; reader 2: 2.1/1.7. Significance was found for reader 1. Pain location correlated with STIR sequences in 64% and 52%, with gadolinium sequences in 70% and 71%. T1-weighted contrast material-enhanced fat-suppressed spin-echo magnetic resonance sequences improve diagnostic accuracy, diagnostic confidence and correlation of MR abnormalities with pain location in MRI of the foot and ankle. However, the additional value is small. (orig.)

  2. Is there an added value of T1-weighted contrast-enhanced fat-suppressed spin-echo MR sequences compared to STIR sequences in MRI of the foot and ankle?

    International Nuclear Information System (INIS)

    Zubler, Veronika; Zanetti, Marco; Dietrich, Tobias J.; Pfirrmann, Christian W.; Mamisch-Saupe, Nadja; Espinosa, Norman

    2017-01-01

    To prospectively compare T1-weighted fat-suppressed spin-echo magnetic resonance (MR) sequences after gadolinium application (T1wGdFS) to STIR sequences in patients with acute and chronic foot pain. In 51 patients referred for MRI of the foot and ankle, additional transverse and sagittal T1wGdFS sequences were obtained. Two sets of MR images (standard protocol with STIR or T1wGdFS) were analysed. Diagnosis, diagnostic confidence, and localization of the abnormality were noted. Standard of reference was established by an expert panel of two experienced MSK radiologists and one experienced foot surgeon based on MR images, clinical charts and surgical reports. Patients reported prospectively localization of pain. Descriptive statistics, McNemar test and Kappa test were used. Diagnostic accuracy with STIR protocol was 80% for reader 1, 67% for reader 2, with contrast-protocol 84%, both readers. Significance was found for reader 2. Diagnostic confidence for reader 1 was 1.7 with STIR, 1.3 with contrast-protocol; reader 2: 2.1/1.7. Significance was found for reader 1. Pain location correlated with STIR sequences in 64% and 52%, with gadolinium sequences in 70% and 71%. T1-weighted contrast material-enhanced fat-suppressed spin-echo magnetic resonance sequences improve diagnostic accuracy, diagnostic confidence and correlation of MR abnormalities with pain location in MRI of the foot and ankle. However, the additional value is small. (orig.)

  3. Gd-EOB-DTPA-Enhanced MR Imaging of the Liver: The Effect on T2 Relaxation Times and Apparent Diffusion Coefficient (ADC)

    International Nuclear Information System (INIS)

    Cieszanowski, Andrzej; Podgórska, Joanna; Rosiak, Grzegorz; Maj, Edyta; Grudziński, Ireneusz P.; Kaczyński, Bartosz; Szeszkowski, Wojciech; Milczarek, Krzysztof; Rowiński, Olgierd

    2016-01-01

    To investigate the effect of gadoxetic acid disodium (Gd-EOB-DTPA) on T2 relaxation times and apparent diffusion coefficient (ADC) values of the liver and focal liver lesions on a 1.5-T system. Magnetic resonance (MR) studies of 50 patients with 35 liver lesions were retrospectively analyzed. All examinations were performed at 1.5T and included T2-weighted turbo spin-echo (TSE) and diffusion-weighted (DW) images acquired before and after intravenous administration of Gd-EOB-DTPA. To assess the effect of this hepatobiliary contrast agent on T2-weighted TSE images and DW images T2 relaxation times and ADC values of the liver and FLLs were calculated and compared pre- and post-injection. The mean T2 relaxation times of the liver and focal hepatic lesions were lower on enhanced than on unenhanced T2-weighted TSE images (decrease of 2.7% and 3.6% respectively), although these differences were not statistically significant. The mean ADC values of the liver showed statistically significant decrease (of 4.6%) on contrast-enhanced DW images, compared to unenhanced images (P>0.05). The mean ADC value of liver lesions was lower on enhanced than on unenhanced DW images, but this difference (of 2.9%) did not reach statistical significance. The mean T2 relaxation times of the liver and focal liver lesions as well as the mean ADC values of liver lesions were not significantly different before and after administration of Gd-EOB-DTPA. Therefore, acquisition of T2-weighted and DW images between the dynamic contrast-enhanced examination and hepatobiliary phase is feasible and time-saving

  4. Initial experience of functional imaging of upper urinary tract neoplasm by diffusion-weighted magnetic resonance imaging

    International Nuclear Information System (INIS)

    Yoshida, Soichiro; Masuda, Hitoshi; Saito, Kazutaka; Kawakami, Satoru; Kihara, Kazunori; Ishii, Chikako

    2008-01-01

    Diffusion-weighted (DW) magnetic resonance imaging (MRI) provides functional information widely used in the diagnosis of acute cerebral stroke. We reported our initial experience of this imaging technique of upper urinary tract (UUT) urothelial carcinoma (UC). Diffusion-weighted magnetic resonance imaging was carried out in 10 consecutive patients with suspected UUT UC. With conventional imaging, seven were diagnosed as having renal pelvic tumors and two were highly suspected of having UUT UC. These nine patients were diagnosed histopathologically as having renal pelvic UC by subsequent operation. The last patient was confirmed as experiencing benign stenosis. DW MRI was obtained with a 1.5-T MR imager without a breath-holding sequence. The apparent diffusion coefficient (ADC) values of renal parenchyma, dilated collecting system, and tumor were calculated. The differences were analyzed using Wilcoxon t-test. On DW MRI, all nine tumors showed hyperintensity with negligible urinary intensity. Two cases of highly suspected UUT UC with unclear conventional MRI had high signal intensity and contrast. The case of benign stenosis had negative DW MRI. The median (range) ADC value of the tumor (0.803 [0.412-0.958] x 10 -3 mm 2 /s) was significantly lower than those of the dilated collecting system (2.19 [1.42-2.40] x 10 -3 ) and renal parenchyma (1.28 [0.922-1.45] x 10 -3 , respectively (P<0.01 and P<0.01). This is the first report on the application of DW MRI for a series of UUT UC. With this technique, a clear demonstration of UUT UC could be obtained. Moreover, this imaging technique is potentially useful to identify small lesions if they have a low diffusion coefficient. (author)

  5. [Relationship between body weight status in early adulthood and body weight change at middle age in adults and type 2 diabetes mellitus].

    Science.gov (United States)

    Zhou, Long; Zhao, Liancheng; Li, Ying; Guo, Min; Wu, Yangfeng

    2016-03-01

    To explore the relationship between weight status in early adulthood and body weight change at middle age in adults and type 2 diabetes mellitus (T2DM). The data of 14 population samples from China Multicenter Collaborative Study of Cardiovascular Epidemiology conducted in 1998 were used. Approximately 1 000 men and women in each sample were surveyed for cardiovascular disease risk factors, including body weight at age 25 years. The body mass index (BMI) at the age 25 years was calculated. The association between body weight in early adulthood and body weight change at middle age and T2DM was examined by using logistic regression model. The incidence of T2DM in low weight group (BMIweight group (BMI: 18.5-23.9 kg/m(2)), overweight group (BMI: 24.0-27.9 kg/m(2)) and obese group (BMI:≥28.0 kg/m(2)) at 25 years old were 2.4%(30/1263), 2.8%(266/9562), 4.0%(70/1739) and 6.4% (7/110), respectively (P value for trendincidence of T2DM for adults with weight change 12.5 kg at middle age were 2.5% (18/712), 1.3%(21/1629), 2.1%(48/2330), 2.3%(59/2585), 3.7%(94/2518), and 4.6% (133/2900) respectively. (P value for trend weight gain were positively correlated with T2DM after adjusted other risk factors (all P values for trend weight gain at middle age were both independently associated with the increased risk of T2DM in middle-aged men and women.

  6. Mechanical Design of HD2, a 15 T Nb3Sn Dipole Magnet with a 35 mm Bore

    Energy Technology Data Exchange (ETDEWEB)

    Ferracin, P.; Bartlett, S.E.; Caspi, S.; Dietderich, D.R.; Gourlay, S.A.; Hafalia, A.R.; Hannaford, C.R.; Lietzke, A.F.; Mattafirri, S.; McInturff, A.D.; Sabbi, G.L.

    2006-06-01

    After the fabrication and test of HD1, a 16 T Nb{sub 3}Sn dipole magnet based on flat racetrack coil configuration, the Superconducting Magnet Program at Lawrence Berkeley National Laboratory (LBNL) is developing the Nb{sub 3}Sn dipole HD2. With a dipole field above 15 T, a 35 mm clear bore, and nominal field harmonics within a fraction of one unit, HD2 represents a further step towards the application of block-type coils to high-field accelerator magnets. The design features tilted racetrack-type ends, to avoid obstructing the beam path, and a 4 mm thick stainless steel tube, to support the coil during the preloading operation. The mechanical structure, similar to the one used for HD1, is based on an external aluminum shell pretensioned with pressurized bladders. Axial rods and stainless steel plates provide longitudinal support to the coil ends during magnet excitation. A 3D finite element analysis has been performed to evaluate stresses and deformations from assembly to excitation, with particular emphasis on conductor displacements due to Lorentz forces. Numerical results are presented and discussed.

  7. Evaluation of Lumbar Intervertebral Disc Degeneration Using T1ρ and T2 Magnetic Resonance Imaging in a Rabbit Disc Injury Model.

    Science.gov (United States)

    Ishikawa, Tetsuhiro; Watanabe, Atsuya; Kamoda, Hiroto; Miyagi, Masayuki; Inoue, Gen; Takahashi, Kazuhisa; Ohtori, Seiji

    2018-04-01

    An in vivo histologic and magnetic resonance imaging (MRI) study of lumbar intervertebral disc (IVD) degeneration was conducted. To clarify the sensitivity and efficacy of T1ρ/T2 mapping for IVD degeneration, the correlation between T1ρ/T2 mapping and degenerative grades and histological findings in the lumbar IVD were investigated. The early signs of IVD degeneration are proteoglycan loss, dehydration, and collagen degradation. Recently, several quantitative MRI techniques have been developed; T2 mapping can be used to evaluate hydration and collagen fiber integrity within cartilaginous tissue, and T1ρ mapping can be used to evaluate hydration and proteoglycan content. Using New Zealand White rabbits, annular punctures of the IVD were made 10 times at L2/3, 5 times at L3/4, and one time at L4/5 using an 18-gauge needle (n=6) or a 21-gauge needle (n=6). At 4 and 8 weeks post-surgery, MRI was performed including T1ρ and T2 mapping. The degree of IVD degeneration was macroscopically assessed using the Thompson grading system. All specimens were cut for hematoxylin and eosin, safranin-O, and toluidine blue staining. Disc degeneration became more severe as the number of punctures increased and when the larger needle was used. T1ρ and T2 values were significantly different between grade 1 and grade 3 IVDs, grade 1 and grade 4 IVDs, grade 2 and grade 3 IVDs, and grade 2 and grade 4 IVDs ( p T2 quantitative MRI could detect these small differences. Our results suggest that T1ρ and T2 mapping are sensitive to degenerative changes of lumbar IVDs and that T1ρ mapping can be used as a clinical tool to identify early IVD degeneration.

  8. Pre-treatment functional MRI of breast cancer: T2* evaluation at 3 T and relationship to dynamic contrast-enhanced and diffusion-weighted imaging.

    Science.gov (United States)

    Kousi, Evanthia; O'Flynn, Elizabeth A M; Borri, Marco; Morgan, Veronica A; deSouza, Nandita M; Schmidt, Maria A

    2018-05-31

    Baseline T2* relaxation time has been proposed as an imaging biomarker in cancer, in addition to Dynamic Contrast-Enhanced (DCE) MRI and diffusion-weighted imaging (DWI) parameters. The purpose of the current work is to investigate sources of error in T2* measurements and the relationship between T2* and DCE and DWI functional parameters in breast cancer. Five female volunteers and thirty-two women with biopsy proven breast cancer were scanned at 3 T, with Research Ethics Committee approval. T2* values of the normal breast were acquired from high-resolution, low-resolution and fat-suppressed gradient-echo sequences in volunteers, and compared. In breast cancer patients, pre-treatment T2*, DCE MRI and DWI were performed at baseline. Pathologically complete responders at surgery and non-responders were identified and compared. Principal component analysis (PCA) and cluster analysis (CA) were performed. There were no significant differences between T2* values from high-resolution, low-resolution and fat-suppressed datasets (p > 0.05). There were not significant differences between baseline functional parameters in responders and non-responders (p > 0.05). However, there were differences in the relationship between T2* and contrast-agent uptake in responders and non-responders. Voxels of similar characteristics were grouped in 5 clusters, and large intra-tumoural variations of all parameters were demonstrated. Breast T2* measurements at 3 T are robust, but spatial resolution should be carefully considered. T2* of breast tumours at baseline is unrelated to DCE and DWI parameters and contribute towards describing functional heterogeneity of breast tumours. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Child dermoid cyst mimicking a craniopharyngioma: the benefit of MRI T2-weighted diffusion sequence.

    Science.gov (United States)

    Amelot, Aymeric; Borha, Alin; Calmon, Raphael; Barbet, Patrick; Puget, Stephanie

    2018-02-01

    Brain dermoid cysts are very rare lesions. Although benign, these cysts may be associated with devastating complications due to mass effect or meningitis. The discovery of completely asymptomatic dermoid cysts in the pediatric population is exceedingly rare. Despite the advances in imaging modalities, it sometimes remains difficult to exclude the differential diagnosis of craniopharyngioma. We describe a 12-year-old boy addressed for suspicion of craniopharyngioma diagnosed by decreased visual acuity, bitemporal hemianopia and a CT scan showing a large hypodense suprasellar lesion with intralesional calcifications. Despite the unusual localization and size of this lesion, the absence of dermal sinus commonly found, and before visualizing a hyperintense mass on MRI-diffusion, the diagnosis of craniopharyngioma was ruled out in favor of a dermoid cyst. Radical excision was performed. In the suprasellar area, craniopharyngioma and dermoid cyst may have very similar radiological aspects: low density masses on CT scan and a hyperintense signal on T1-weighted MRI sequences with a variable signal on T2-weighted sequences. Hitherto, only two cases in literature have described suprasellar dermoid cyst. Their initial diagnosis was facilitated by the presence of a dermal sinus.

  10. Diffusion-Weighted Magnetic Resonance Imaging in Renal Lesion Characterization

    Directory of Open Access Journals (Sweden)

    Elif Karadeli

    2012-03-01

    Conclusion: The technique has the advantage that it is non-invasive without need for gadolinium administration, takes about 2 minute. This method provides qualitative and quantitative infomation on tissue characterization. DA-MRI and ADC values are important for characterization of renal lesions. Especially, utility of diffusion-weighted magnetic resonance imaging in the patients with risk for nephrogenic systemic fibrosis (NSF could be beneficial. [Cukurova Med J 2012; 37(1: 27-36

  11. RNaseT2 knockout rats exhibit hippocampal neuropathology and deficits in memory.

    Science.gov (United States)

    Sinkevicius, Kerstin W; Morrison, Thomas R; Kulkarni, Praveen; Cagliostro, Martha K Caffrey; Iriah, Sade; Malmberg, Samantha; Sabrick, Julia; Honeycutt, Jennifer A; Askew, Kim L; Trivedi, Malav; Ferris, Craig F

    2018-05-10

    RNASET2 deficiency in humans is associated with infant cystic leukoencephalopathy, which causes psychomotor impairment, spasticity, and epilepsy. A zebrafish mutant model suggests that loss of RNASET2 function leads to neurodegeneration due to the accumulation of non-degraded RNA in the lysosomes. The goal of this study was to characterize the first rodent model of RNASET2 deficiency. The brains of 3- and 12-month-old RNaseT2 knockout rats were studied using multiple magnetic resonance imaging modalities and behavioral tests. While T1 and T2 weighted images of RNaseT2 knockout rats exhibited no evidence of cystic lesions, the prefrontal cortex and hippocampal complex were enlarged in knockout animals. Diffusion weighted imaging showed altered anisotropy and putative gray matter changes in the hippocampal complex of the RNaseT2 knockout rats. Immunohistochemistry for glial fibrillary acidic protein (GFAP) showed the presence of hippocampal neuroinflammation. Decreased levels of lysosome-associated membrane protein 2 (LAMP2) and elevated acid phosphatase and β-N-Acetylglucosaminidase (NAG) activities indicated that the RNASET2 knockout rats likely had altered lysosomal function and potential defects in autophagy. Object recognition tests confirmed the RNaseT2 knockout rats exhibited memory deficits. However, the Barnes maze, and balance beam and rotarod tests, indicated there were no differences in spatial memory or motor impairments, respectively. Overall, patients with RNASET2 deficiency exhibited a more severe neurodegeneration phenotype than was observed in the RNaseT2 knockout rats. However, the vulnerability of the knockout rat hippocampus as evidenced by neuroinflammation, altered lysosomal function, and cognitive defects indicates this is still a useful in vivo model to study RNASET2 function. © 2018. Published by The Company of Biologists Ltd.

  12. Estimation of T2 relaxation time of breast cancer: Correlation with clinical, imaging and pathological features

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Mirinae; Sohn, Yu Mee [Dept. of Radiology, Kyung Hee University Hospital, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Ryu, Jung Kyu; Jahng, Geon Ho; Rhee, Sun Jung; Oh, Jang Hoon; Won, Kyu Yeoun [Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of)

    2017-01-15

    The purpose of this study was to estimate the T2* relaxation time in breast cancer, and to evaluate the association between the T2* value with clinical-imaging-pathological features of breast cancer. Between January 2011 and July 2013, 107 consecutive women with 107 breast cancers underwent multi-echo T2*-weighted imaging on a 3T clinical magnetic resonance imaging system. The Student's t test and one-way analysis of variance were used to compare the T2* values of cancer for different groups, based on the clinical-imaging-pathological features. In addition, multiple linear regression analysis was performed to find independent predictive factors associated with the T2* values. Of the 107 breast cancers, 92 were invasive and 15 were ductal carcinoma in situ (DCIS). The mean T2* value of invasive cancers was significantly longer than that of DCIS (p = 0.029). Signal intensity on T2-weighted imaging (T2WI) and histologic grade of invasive breast cancers showed significant correlation with T2* relaxation time in univariate and multivariate analysis. Breast cancer groups with higher signal intensity on T2WI showed longer T2* relaxation time (p = 0.005). Cancer groups with higher histologic grade showed longer T2* relaxation time (p = 0.017). The T2* value is significantly longer in invasive cancer than in DCIS. In invasive cancers, T2* relaxation time is significantly longer in higher histologic grades and high signal intensity on T2WI. Based on these preliminary data, quantitative T2* mapping has the potential to be useful in the characterization of breast cancer.

  13. The use of diffusion-weighted magnetic resonance imaging in the differentiation between benign and malignant breast lesions

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Fernanda Philadelpho Arantes; Martins, Gabriela; Domingues, Marisa Nassar Aidar; Domingues, Romeu Cortes [Clinica de Diagnostico por Imagem (CDPI), Rio de Janeiro, RJ (Brazil)], e-mail: fephila@gmail.com; Figueiredo, Eduardo [GE Healthcare, Sao Paulo, SP (Brazil); Fonseca, Lea Mirian Barbosa da [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Faculdade de Medicina

    2009-09-15

    Objective: to study the utility of diffusion-weighted magnetic resonance imaging in the differentiation between benign and malignant breast lesions. Materials and methods: forty-five women (mean age, 46.1 years) with 52 focal breast lesions underwent diffusion-weighted magnetic resonance imaging. The calculation of apparent diffusion coefficient (ADC) was based on the ADC map reflecting five b values (0, 250, 500, 750, and 1000 s/mm{sup 2}). The mean ADC value of each lesion was correlated with imaging findings and histopathologic results. Cutoff ADC, sensitivity and specificity of diffusion-weighted imaging in the differentiation between benign and malignant lesions were calculated. P < 0.05 was considered as statistically significant. Results: the mean ADC was significantly lower for malignant lesions (0.92 {+-} 0.26 x 10{sup -3} mm{sup 2}/s) as compared with benign lesions (1.50 {+-} 0.34 x 10{sup -3} mm{sup 2}/s) (P < 0.0001). Diffusion-weighted imaging showed high sensitivity and specificity (both, 92.3%) in the differentiation between benign and malignant lesions. Conclusion: diffusion-weighted imaging is a potential resource as an adjuvant to breast magnetic resonance imaging to differentiate benign from malignant lesions. Such sequence can be easily added to the standard breast magnetic resonance imaging protocol, without implying any significant increase in examination time. (author)

  14. Significance of high-intensity signals on cranial MRI T{sub 2} weighted image in diagnosis of age-associated dementia. From a viewpoint of reversibility of brain function

    Energy Technology Data Exchange (ETDEWEB)

    Kishiro, Masaki [St. Marianna Univ., Kawasaki, Kanagawa (Japan). School of Medicine

    1994-08-01

    This study was undertaken to determine whether changes of EEG band profile in patients showing high-intensity signal (HIS) on cranial magnetic resonance images (MRI), who had however no vascular lesions on cranial CT, were similar to those in multi-infarct dementia (MID) or senile dementia of Alzheimer type (SDAT) patients and to determine the significance of HIS in the diagnosis of SDAT. Forty-two patients with dementia diagnosed according to DSM-III-R were divided into HIS (n=21), MID (n=13), and SDAT (n=8) based on CT and MRI findings. Multi-infarcted lesions were seen on cranial CT and HIS was seen on cranial MRI in MID patients. There were no abnormal lesions except brain atrophy on cranial CT and MRI in SDAT patients. Appearance rates (%) of the 2-18 c/s frequency bands using computerized quantitative EEG before and after administration of protirelin tartrate (TRH-T) were analyzed in the frontal, central, parietal and occipital areas of the brain. There were no significant differences in appearance rates of EEG frequency bands before administration of TRH-T in HIS, MID, and SDAT patients. A significant decrease in appearance rates of slow waves and a significant increase in appearance rates of {alpha} waves were observed after administration of TRH-T in the four areas in MID patients compared with those before administration. No significant differences in appearance rates of EEG frequency bands were observed after administration of TRH-T in the four areas in HIS and SDAT patients compared with those before administration. Changes of the EEG band profile in HIS patients were similar to those in SDAT patients. In the presence of appearance of HSI on cranial MRI T{sub 2} weighted images, the possibility of SDAT patients cannot be excluded. Therefore, SDAT should be diagnosed based on both clinical data and the absence of brain vascular lesions on cranial CT. Also, HIS on MRI T{sub 2}-weighted images is considered to reflect non-vascular lesions. (J.N.P.).

  15. Visual discrimination among patients with depression and schizophrenia and healthy individuals using semiquantitative color-coded fast spin-echo T1-weighted magnetic resonance imaging

    International Nuclear Information System (INIS)

    Sasaki, Makoto; Kudo, Kohsuke; Narumi, Shinsuke; Shibata, Eri; Ohtsuka, Kotaro; Endoh, Jin; Sakai, Akio

    2010-01-01

    Fast spin-echo (FSE) T1-weighted (T1W) magnetic resonance imaging (MRI) at 3T, which is sensitive to neuromelanin-related contrast, can quantitatively detect signal alterations in the locus ceruleus (LC) and the substantia nigra pars compacta (SNc) of depressive and schizophrenic patients; however, its qualitative diagnostic performance remains unknown. We investigated whether visual interpretation of semiquantitative color maps can be used for discriminating between depressive and schizophrenic patients and healthy individuals. We retrospectively examined 23 patients with major depression, 23 patients with schizophrenia, and 23 age-matched healthy controls by using a FSE-T1W MRI technique. Semiquantitative color maps of sections through the LC and SNc were visually interpreted by nine raters using a continuous confidence rating scale for receiver operating characteristic (ROC) analysis. The area under the ROC curve (Az), which reflects the performance in differentiating between depressive patients and controls, was 0.88, and the sensitivity and specificity at the maximum likelihood were 76% and 83%, respectively. In contrast, the Az value, sensitivity, and specificity values between schizophrenics and controls and between depressives and schizophrenics were 0.66 and 0.69, 42% and 48%, and 82% and 84%, respectively. Semiquantitative, color-coded FSE-T1W MRI at 3T can be used for visually differentiating depressive patients from healthy individuals with a substantially high likelihood, but this technique cannot be applied to distinguish schizophrenic patients from the other two groups. (orig.)

  16. Visual discrimination among patients with depression and schizophrenia and healthy individuals using semiquantitative color-coded fast spin-echo T1-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Makoto; Kudo, Kohsuke; Narumi, Shinsuke [Iwate Medical University, Advanced Medical Research Center, Morioka (Japan); Shibata, Eri; Ohtsuka, Kotaro; Endoh, Jin; Sakai, Akio [Iwate Medical University, Department of Neuropsychiatry, Morioka (Japan)

    2010-02-15

    Fast spin-echo (FSE) T1-weighted (T1W) magnetic resonance imaging (MRI) at 3T, which is sensitive to neuromelanin-related contrast, can quantitatively detect signal alterations in the locus ceruleus (LC) and the substantia nigra pars compacta (SNc) of depressive and schizophrenic patients; however, its qualitative diagnostic performance remains unknown. We investigated whether visual interpretation of semiquantitative color maps can be used for discriminating between depressive and schizophrenic patients and healthy individuals. We retrospectively examined 23 patients with major depression, 23 patients with schizophrenia, and 23 age-matched healthy controls by using a FSE-T1W MRI technique. Semiquantitative color maps of sections through the LC and SNc were visually interpreted by nine raters using a continuous confidence rating scale for receiver operating characteristic (ROC) analysis. The area under the ROC curve (Az), which reflects the performance in differentiating between depressive patients and controls, was 0.88, and the sensitivity and specificity at the maximum likelihood were 76% and 83%, respectively. In contrast, the Az value, sensitivity, and specificity values between schizophrenics and controls and between depressives and schizophrenics were 0.66 and 0.69, 42% and 48%, and 82% and 84%, respectively. Semiquantitative, color-coded FSE-T1W MRI at 3T can be used for visually differentiating depressive patients from healthy individuals with a substantially high likelihood, but this technique cannot be applied to distinguish schizophrenic patients from the other two groups. (orig.)

  17. Magnetization transfer imaging identifies basal ganglia abnormalities in adult ADHD that are invisible to conventional T1 weighted voxel-based morphometry

    Directory of Open Access Journals (Sweden)

    Arjun Sethi

    2017-01-01

    Full Text Available In childhood, Attention Deficit Hyperactivity Disorder (ADHD is reliably associated with reduced volume of the striatum. In contrast, striatal abnormalities are infrequently detected in voxel-based morphometry (VBM neuroimaging studies of adults with ADHD. This discrepancy has been suggested to reflect normalisation of striatal morphology with age and prolonged treatment of symptoms. If so, this would indicate that while striatal abnormalities are linked to symptom expression in childhood, they cannot explain the persistence of these symptoms in adulthood. However, this may not be case. Instead, we hypothesized that the lack of evidence for striatal abnormalities in adult ADHD may reflect poor sensitivity of typical (T1-weighted neuroimaging to detect subcortical differences. To address this, we acquired both magnetisation transfer (MT saturation maps optimised for subcortical contrast, and conventional T1-weighted images in 30 adults with ADHD and 30 age, IQ, gender and handedness-matched controls. Using VBM of both datasets, we demonstrate volumetric reductions within the left ventral striatum on MT that are not observed on identically pre-processed T1-weighted images from the same participants. Nevertheless, both techniques reported similar sensitivity to cortical abnormalities in the right inferior parietal lobe. Additionally, we show that differences in striatal iron may potentially explain this reduced sensitivity of T1-weighted images in adults. Together, these findings indicate that prior VBM studies reporting no abnormalities in striatal volume in adult ADHD might have been compromised by the methodological insensitivity of T1-weighted VBM to subcortical differences, and that structural abnormalities of the striatum in ADHD do indeed persist into adulthood.

  18. Magnetic and magnetoelastic properties of the random anisotropy amorphous magnets Tb2(FexNi1-x)

    International Nuclear Information System (INIS)

    De la Fuente, C.; Arnaudas, J.I.; Del Moral, A.; Ciria, M.

    1996-01-01

    Amorphous Tb 2 (Fe x Ni 1-x ) compounds show the strongest random anisotropy known: D/J≅5.2, between crystal field and exchange strengths, separately obtained. The magnetic phase diagram shows two speri-magnetic phases. The effective magnetic moment is reduced, μ eff. (5 K, 12 T)≅7.2 μ B /Tb 3+ . Magnetostriction is very large and constant, λ t (5 K, 12 T)≅4.1.10 -3 . The local distribution of Tb 3+ ions is aspherical. (orig.)

  19. Metallic artifacts in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Abe, Eiji; Okuyama, Koichiro; Ishikawa, Noriyuki; Hongo, Michio; Sato, Kozo; Sashi, Ryuji; Ishikawa, Eijiro.

    1995-01-01

    Seven metallic implants with different content of magnetic materials were compared in terms of the degree of MRI artifact. The degree of artifact well correlated with the total content of iron and cobalt than the total content of ferromagnets (iron, cobalt, nickel). No significant difference was observed regarding artifact among 4 titanium alloys containing very small amount of ferromagnet (0.058%-2.5%). Pedicle screws were made from different alloys in the same shape. Those screws were inserted into the swine vertebrae and artifact was evaluated by MRI. The degree of artifact was SUS316 (stainless steel)>MP-35N (cobalt alloy)>Ti-6AI-4V (titanium alloy), 1.5 Tesla>0.5 Tesla as for magnetic intensity, and T2 (gradient echo)>T2 (long SE)>proton density>T1 as for exposure condition. The condition of the site screw was inserted in the vertebral canal was detectable by T1-weighted images of titanium alloy and cobalt alloy in 0.5 Tesla and T1-weighted images of titanium alloy in 1.5 Tesla. (S.Y)

  20. Estimation of isotropic nuclear magnetic shieldings in the CCSD(T) and MP2 complete basis set limit using affordable correlation calculations

    DEFF Research Database (Denmark)

    Kupka, Teobald; Stachów, Michal; Kaminsky, Jakub

    2013-01-01

    , estimated from calculations with the family of polarizationconsistent pcS-n basis sets is reported. This dependence was also supported by inspection of profiles of deviation between CBS estimated nuclear shieldings and obtained with significantly smaller basis sets pcS-2 and aug-cc-pVTZ-J for the selected......A linear correlation between isotropic nuclear magnetic shielding constants for seven model molecules (CH2O, H2O, HF, F2, HCN, SiH4 and H2S) calculated with 37 methods (34 density functionals, RHF, MP2 and CCSD(T) ), with affordable pcS-2 basis set and corresponding complete basis set results...... set of 37 calculation methods. It was possible to formulate a practical approach of estimating the values of isotropic nuclear magnetic shielding constants at the CCSD(T)/CBS and MP2/CBS levels from affordable CCSD(T)/pcS-2, MP2/pcS-2 and DFT/CBS calculations with pcS-n basis sets. The proposed method...