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Sample records for t2 weighted magnetic

  1. Reactive Sclerosis: Hyperintense Appearance on T2-Weighted Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Kanberoglu, K.; Kantarci, F.; Yilmaz, M.H.

    2005-01-01

    Osteosclerosis is defined as increased density of bone on X-ray imaging studies. It is known that osteosclerosis appears hypointense on both T1- and T2-weighted magnetic resonance imaging sequences. In this review, we present our experience in various sclerotic skeletal pathologies that appear hyperintense on T2-weighted magnetic resonance imaging. We emphasize the possible pathophysiological mechanisms that may cause this appearance, such as bone marrow edema and/or composition of newly formed bone

  2. Reactive Sclerosis: Hyperintense Appearance on T2-Weighted Magnetic Resonance Imaging

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    Kanberoglu, K.; Kantarci, F.; Yilmaz, M.H. [Istanbul Univ., Cerrahpasa Medical Faculty (Turkey). Dept. of Radiology

    2005-11-01

    Osteosclerosis is defined as increased density of bone on X-ray imaging studies. It is known that osteosclerosis appears hypointense on both T1- and T2-weighted magnetic resonance imaging sequences. In this review, we present our experience in various sclerotic skeletal pathologies that appear hyperintense on T2-weighted magnetic resonance imaging. We emphasize the possible pathophysiological mechanisms that may cause this appearance, such as bone marrow edema and/or composition of newly formed bone.

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

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    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.)

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

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    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

  5. Texture features on T2-weighted magnetic resonance imaging: new potential biomarkers for prostate cancer aggressiveness

    Science.gov (United States)

    Vignati, A.; Mazzetti, S.; Giannini, V.; Russo, F.; Bollito, E.; Porpiglia, F.; Stasi, M.; Regge, D.

    2015-04-01

    To explore contrast (C) and homogeneity (H) gray-level co-occurrence matrix texture features on T2-weighted (T2w) Magnetic Resonance (MR) images and apparent diffusion coefficient (ADC) maps for predicting prostate cancer (PCa) aggressiveness, and to compare them with traditional ADC metrics for differentiating low- from intermediate/high-grade PCas. The local Ethics Committee approved this prospective study of 93 patients (median age, 65 years), who underwent 1.5 T multiparametric endorectal MR imaging before prostatectomy. Clinically significant (volume ≥0.5 ml) peripheral tumours were outlined on histological sections, contoured on T2w and ADC images, and their pathological Gleason Score (pGS) was recorded. C, H, and traditional ADC metrics (mean, median, 10th and 25th percentile) were calculated on the largest lesion slice, and correlated with the pGS through the Spearman correlation coefficient. The area under the receiver operating characteristic curve (AUC) assessed how parameters differentiate pGS = 6 from pGS ≥ 7. The dataset included 49 clinically significant PCas with a balanced distribution of pGS. The Spearman ρ and AUC values on ADC were: -0.489, 0.823 (mean) -0.522, 0.821 (median) -0.569, 0.854 (10th percentile) -0.556, 0.854 (25th percentile) -0.386, 0.871 (C); 0.533, 0.923 (H); while on T2w they were: -0.654, 0.945 (C); 0.645, 0.962 (H). AUC of H on ADC and T2w, and C on T2w were significantly higher than that of the mean ADC (p = 0.05). H and C calculated on T2w images outperform ADC parameters in correlating with pGS and differentiating low- from intermediate/high-risk PCas, supporting the role of T2w MR imaging in assessing PCa biological aggressiveness.

  6. 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

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

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    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.

  8. Clinical utility of optimized three-dimensional T1-, T2-, and T2*-weighted sequences in spinal magnetic resonance imaging.

    Science.gov (United States)

    Tanitame, Nobuko; Tanitame, Keizo; Awai, Kazuo

    2017-04-01

    This article reviews the clinical utility of 3D magnetic resonance imaging (MRI) sequences optimized for the evaluation of various intraspinal lesions. First, intraspinal tumors with hypervascular components and arteriovenous malformations (AVM) are clearly shown on contrast-enhanced (CE)-3D T1-weighted gradient-echo (GE) sequences with high spatial resolution. Second, dynamic CE-3D time-resolved magnetic resonance angiography (MRA) shows delineated feeding arteries of intraspinal AVM or arteriovenous fistula (AVF), greatly aiding subsequent digital subtraction angiography (DSA). Third, 3D multiecho T2*-weighted GE sequences are used to visualize intraspinal structures and spinal cord lesions and are sensitive to the magnetic susceptibility of intraspinal hemorrhages. Three-dimensional balanced steady-state free precession (SSFP) and multishot 3D balanced non-SSFP sequences produce contiguous thin images with high signal-to-noise ratio (SNR) in short scanning times. Intraspinal cystic lesions and small nerve-root tumors in subarachnoid space can be viewed using 3D balanced SSFP. Spinal cord myelomalacia and cord compression can be evaluated on fat-suppressed multishot 3D balanced non-SSFP. Finally, a 3D T2-weighted fast spin-echo (FSE) sequence with variable flip angle (FA) refocusing pulse improves through-plane spatial resolution over conventional 2D T2-weighted FSE sequences while matching image contrast.

  9. Atlas-Free Cervical Spinal Cord Segmentation on Midsagittal T2-Weighted Magnetic Resonance Images

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    Chun-Chih Liao

    2017-01-01

    Full Text Available An automatic atlas-free method for segmenting the cervical spinal cord on midsagittal T2-weighted magnetic resonance images (MRI is presented. Pertinent anatomical knowledge is transformed into constraints employed at different stages of the algorithm. After picking up the midsagittal image, the spinal cord is detected using expectation maximization and dynamic programming (DP. Using DP, the anterior and posterior edges of the spinal canal and the vertebral column are detected. The vertebral bodies and the intervertebral disks are then segmented using region growing. Then, the anterior and posterior edges of the spinal cord are detected using median filtering followed by DP. We applied this method to 79 noncontrast MRI studies over a 3-month period. The spinal cords were detected in all cases, and the vertebral bodies were successfully labeled in 67 (85% of them. Our algorithm had very good performance. Compared to manual segmentation results, the Jaccard indices ranged from 0.937 to 1, with a mean of 0.980 ± 0.014. The Hausdorff distances between the automatically detected and manually delineated anterior and posterior spinal cord edges were both 1.0 ± 0.5 mm. Used alone or in combination, our method lays a foundation for computer-aided diagnosis of spinal diseases, particularly cervical spondylotic myelopathy.

  10. Hemosiderin detected by T2*-weighted magnetic resonance imaging in patients with unruptured cerebral aneurysms: indication of previous bleeding?

    Science.gov (United States)

    Takada, Shihomi; Inoue, Takashi; Niizuma, Kuniyasu; Shimizu, Hiroaki; Tominaga, Teiji

    2011-01-01

    Previous bleeding from a cerebral aneurysm indicates a higher risk of rupture. Hemosiderin may be detected during aneurysm surgery or by preoperative imaging sensitive to hemosiderin. The detection of hemosiderin deposits by T(2)*-weighted magnetic resonance (MR) imaging was evaluated in 49 patients with unruptured cerebral aneurysms who underwent open surgery. MR imaging was performed using 3.0 tesla MR scanner. Two sequences of T(2)*-weighted imaging, and proton density images were obtained. Preliminary study in patients with old subarachnoid hemorrhage provided the definitions of likely pathological findings during surgery and on T(2)*-weighted imaging due to previous hemorrhage. Hemosiderin deposits in the subarachnoid space were observed during surgery in 9 of the 49 patients, although no obvious rupture site was detected around the aneurysm wall. Size, presence of bleb, location, and number of aneurysms showed no significant difference between patients with and without hemosiderin deposition. Hypointense areas on T(2)*-weighted imaging were recognized in four patients. The mean size of the aneurysms in these patients was 9.8 mm, significantly larger than those in other patients (p = 0.029). Hemosiderin deposits were observed during surgery in sites close to the lesions on T(2)*-weighted imaging in two of these four patients. Hemosiderin deposits are not rare in patients with unruptured aneurysms, and preoperative T(2)*-weighted imaging can detect such deposits.

  11. 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.

  12. 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)

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

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    Antonio C. Westphalen

    2009-04-01

    Full Text Available 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. MATERIAL 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.

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

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    Westphalen, Antonio C.; Kurhanewicz, John; Cunha, Rui M.G.; Hsu, I-Chow; Kornak, John; Zhao, Shoujun; Coakley, Fergus V. [University of California San Francisco, San Francisco, CA (United States). Dept. of Radiology. Abdominal Imaging Section], e-mail: antonio.westphalen@radiology.ucsf.edu

    2009-01-15

    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)

  15. Cortical pathology in multiple sclerosis detected by the T1/T2-weighted ratio from routine magnetic resonance imaging.

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    Righart, Ruthger; Biberacher, Viola; Jonkman, Laura E; Klaver, Roel; Schmidt, Paul; Buck, Dorothea; Berthele, Achim; Kirschke, Jan S; Zimmer, Claus; Hemmer, Bernhard; Geurts, Jeroen J G; Mühlau, Mark

    2017-10-01

    In multiple sclerosis, neuropathological studies have shown widespread changes in the cerebral cortex. In vivo imaging is critical, because the histopathological substrate of most measurements is unknown. Using a novel magnetic resonance imaging analysis technique, based on the ratio of T1- and T2-weighted signal intensities, we studied the cerebral cortex of a large cohort of patients in early stages of multiple sclerosis. A total of 168 patients with clinically isolated syndrome or relapsing-remitting multiple sclerosis (Expanded Disability Status Scale: median = 1, range = 0-3.5) and 80 age- and sex-matched healthy controls were investigated. We also searched for the histopathological substrate of the T1/T2-weighted ratio by combining postmortem imaging and histopathology in 9 multiple sclerosis brain donors. Patients showed lower T1/T2-weighted ratio values in parietal and occipital areas. The 4 most significant clusters appeared in the medial occipital and posterior cingulate cortex (each left and right). The decrease of the T1/T2-weighted ratio in the posterior cingulate was related to performance in attention. Analysis of the T1/T2-weighted ratio values of postmortem imaging yielded a strong correlation with dendrite density but none of the other parameters including myelin. The T1/T2-weighted ratio decreases in early stages of multiple sclerosis in a widespread manner, with a preponderance of posterior areas and with a contribution to attentional performance; it seems to reflect dendrite pathology. As the method is broadly available and applicable to available clinical scans, we believe that it is a promising candidate for studying and monitoring cortical pathology or therapeutic effects in multiple sclerosis. Ann Neurol 2017;82:519-529. © 2017 The Authors Annals of Neurology published by Wiley Periodicals, Inc. on behalf of American Neurological Association.

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

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    Du, D; Mutic, S; Hu, Y [Washington University School of Medicine, Saint Louis, MO (United States); Caruthers, S [Philips Healthcare, Cleveland, OH (United States); Glide-Hurst, C [Henry Ford Health System, Detroit, MI (United States); Low, D [UCLA, Los Angeles, CA (United States)

    2014-06-01

    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.

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

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    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.

  18. Diagnostic workup of primary sclerosing cholangitis: The benefit of adding gadoxetic acid-enhanced T1-weighted magnetic resonance cholangiography to conventional T2-weighted magnetic resonance cholangiography

    International Nuclear Information System (INIS)

    Nolz, R.; Asenbaum, U.; Schoder, M.; Wibmer, A.; Einspieler, H.; Prusa, A.M.; Peck-Radosavljevic, M.; Ba-Ssalamah, A.

    2014-01-01

    Aim: To evaluate the value of gadoxetic acid-enhanced T1-weighted (T1W) magnetic resonance cholangiography (MRC) versus conventional T2-weighted (T2W) MRC compared to endoscopic retrograde cholangiopancreatography (ERCP) in patients with primary sclerosing cholangitis (PSC). Materials and methods: Based on T1W MRC, PSC patients were classified into a regular (RG) and a delayed (DG) excreting group, with an absence of gadoxetic acid in the common bile duct at 20 min. Beading, pruning, and gradation of central bile duct stenosis, evaluated by T1W and T2W MRC, were compared to ERCP. Liver parenchymal enhancement was measured in both study groups and compared to a reference group (n = 20) without a history of liver disease. Two readers performed all measurements. Results: Based on beading and pruning of the peripheral bile ducts, sensitivities, specificities, and accuracies for reader 1 were 0.17/0.43, 0/0.17, and 0.15/0.31 for T1W MRC, and 0.83/0.86, 1/0.83, and 0.85/0.85 for T2W MRC (p = 0.004). For reader 2 sensitivities, specificities, and accuracies were 0.25/0.57, 0/0.33, and 0.23/0.46 for T1W MRC, and 0.92/1, 1/0.83, and 0.92/0.92 for T2W MRC (p = 0.012). Compared to ERCP, central bile duct stenoses were significantly overestimated (p < 0.001) by T2W MRC. A significantly lower parenchymal enhancement was found in the DG (n = 7) compared to the RG (n = 13), and compared to the reference group (p < 0.001). Conclusion: The combined performance of T2W and T1W MRC may provide a comprehensive imaging workup of PSC, including morphological and functional information resulting in optimal management

  19. 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.)

  20. 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.)

  1. High-Resolution T2-Weighted Abdominal Magnetic Resonance Imaging Using Respiratory Triggering: Impact of Butylscopolamine on Image Quality

    International Nuclear Information System (INIS)

    Wagner, M.; Klessen, C.; Rief, M.; Elgeti, T.; Taupitz, M.; Hamm, B.; Asbach, P.

    2008-01-01

    Background: Respiratory triggering allows the acquisition of high-resolution magnetic resonance (MR) images of the upper abdomen. However, the depiction of organs close to the gastrointestinal tract can be considerably impaired by ghosting artifacts and blurring caused by bowel peristalsis. Purpose: To evaluate the effect of gastrointestinal motion suppression by intramuscular butylscopolamine administration on the image quality of a respiratory-triggered T2-weighted turbo spin-echo (T2w TSE) sequence of the upper abdomen. Material and Methods: Images of 46 patients were retrospectively analyzed. Twenty-four patients had received intramuscular injection of 40 mg butylscopolamine immediately before MR imaging. Fourteen of the 24 patients in the butylscopolamine group underwent repeat imaging after a mean of 29 min. Quantitative analysis of the ghosting artifacts was done by measuring signal intensities in regions of interest placed in air anterior to the patient. In addition, image quality was assessed qualitatively by two radiologists by consensus. Results: Spasmolytic medication with butylscopolamine reduced ghosting artifacts and significantly improved image quality of the respiratory-triggered T2w TSE sequence. The most pronounced effect of butylscopolamine administration on image quality was found for the pancreas and the left hepatic lobe. The rate of examinations with excellent or good depiction of the pancreas and the left hepatic lobe in the group without premedication and in the butylscopolamine group was 55% vs. 96% (pancreatic head), 35% vs. 88% (pancreatic body), 43% vs. 96% (pancreatic tail), and 45% vs. 83% (left hepatic lobe), respectively. Regarding the duration of the effect of intramuscular butylscopolamine, repeat imaging after a mean of 29 min did not result in a significant deterioration of image quality. Conclusion: Intramuscular butylscopolamine administration significantly improves image quality of respiratory-triggered T2-weighted abdominal

  2. High-Resolution T2-Weighted Abdominal Magnetic Resonance Imaging Using Respiratory Triggering: Impact of Butylscopolamine on Image Quality

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, M.; Klessen, C.; Rief, M.; Elgeti, T.; Taupitz, M.; Hamm, B.; Asbach, P. (Dept. of Radiology, Charite - Universitaetsmedizin Berlin, Berlin (DE))

    2008-05-15

    Background: Respiratory triggering allows the acquisition of high-resolution magnetic resonance (MR) images of the upper abdomen. However, the depiction of organs close to the gastrointestinal tract can be considerably impaired by ghosting artifacts and blurring caused by bowel peristalsis. Purpose: To evaluate the effect of gastrointestinal motion suppression by intramuscular butylscopolamine administration on the image quality of a respiratory-triggered T2-weighted turbo spin-echo (T2w TSE) sequence of the upper abdomen. Material and Methods: Images of 46 patients were retrospectively analyzed. Twenty-four patients had received intramuscular injection of 40 mg butylscopolamine immediately before MR imaging. Fourteen of the 24 patients in the butylscopolamine group underwent repeat imaging after a mean of 29 min. Quantitative analysis of the ghosting artifacts was done by measuring signal intensities in regions of interest placed in air anterior to the patient. In addition, image quality was assessed qualitatively by two radiologists by consensus. Results: Spasmolytic medication with butylscopolamine reduced ghosting artifacts and significantly improved image quality of the respiratory-triggered T2w TSE sequence. The most pronounced effect of butylscopolamine administration on image quality was found for the pancreas and the left hepatic lobe. The rate of examinations with excellent or good depiction of the pancreas and the left hepatic lobe in the group without premedication and in the butylscopolamine group was 55% vs. 96% (pancreatic head), 35% vs. 88% (pancreatic body), 43% vs. 96% (pancreatic tail), and 45% vs. 83% (left hepatic lobe), respectively. Regarding the duration of the effect of intramuscular butylscopolamine, repeat imaging after a mean of 29 min did not result in a significant deterioration of image quality. Conclusion: Intramuscular butylscopolamine administration significantly improves image quality of respiratory-triggered T2-weighted abdominal

  3. 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)

  4. 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)

  5. Multifocal hemosiderin depositions on T2*-weighted magnetic resonance imaging in a patient with pathology-proven systemic diffuse large B-cell lymphoma.

    Science.gov (United States)

    Yang, Xun-zhe; Ni, Jun; Cui, Li-ying

    2014-09-25

    Intracranial hemorrhage in central nervous system lymphoma is extremely rare. T2*-weighted gradient-echo magnetic resonance imaging is of particularly use in detecting silent hemorrhage as hypointense signals due to the deposition of paramagnetic hemosiderin or mineralization. Multifocal hemosiderin depositions caused by chronic silent hemorrhage have not yet been identified in patients with central nervous system involvement of systemic lymphoma. We present an unexpected radiographic feature on T2*-weighted gradient-echo magnetic resonance imaging in a patient with central nervous system involvement of pathologically confirmed systemic diffuse large B-cell lymphoma. A 56-year-old woman presented with lower extremities weakness and progressive cognitive decline for four months. Conventional brain magnetic resonance imaging demonstrated multiple lesions with hypointensities on T1-weighted images and hyperintensities on T2-weighted images and fluid attenuated inversion recovery in both hemispheres. She was then transferred to our hospital. This is the first report of pathologically confirmed case of CNS involvement of systemic diffuse large B-cell lymphoma with multifocal silent hemosiderin depositions detected by T2*-weighted gradient-echo magnetic resonance imaging. Even though uncommon, our report offers an insight that CNS lymphoma could present with multifocal silent hemosiderin depositions on T2*-weighted gradient-echo magnetic resonance imaging. Further studies were expected for exploring the association between this radiologic feature and systemic lymphoma and their underlying mechanisms.

  6. 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

  7. 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)

  8. 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

  9. Dotlike hemosiderin spots on T2*-weighted magnetic resonance imaging as a predictor of stroke recurrence: a prospective study.

    Science.gov (United States)

    Imaizumi, Toshio; Horita, Yoshifumi; Hashimoto, Yuji; Niwa, Jun

    2004-12-01

    Microangiopathy associated with hypertension is a notable cause of cerebral small vessel disease (SVD), including deep intracerebral hemorrhage (ICH) and lacunar infarct. Dotlike low-intensity spots (dotlike hemosiderin spots: dotHSs) on T2*-weighted magnetic resonance (MR) images have been histologically diagnosed as old cerebral microbleeds associated with lipohyalinosis, amyloid angiopathy, or other microangiopathies and located in deep or subcortical regions. The aim of this study was to determine whether dotHSs indicate the severity of microangiopathy, and if so, whether large numbers of deep dotHSs are associated with SVD recurrence. The authors prospectively analyzed the number of dotHSs in 337 patients-191 men and 146 women with a mean age of 66 +/- 10.4 years (range 37-94 years)-with SVD (199 ICHs and 138 lacunar infarcts) who had been consecutively admitted to Hakodate Municipal Hospital. The follow-up period was 3.5 to 42 months (22.5 +/- 13.1 months). Patients were divided into two groups based on the recurrence. The hazard ratio (HR) for recurrence was estimated based on the Cox proportional hazard model by using the number of deep and subcortical dotHSs as well as other factors. Of 337 patients, 20 were readmitted with recurrence. Results of a multivariate analysis revealed an elevated rate of recurrence in patients with many subcortical dotHSs (> or = 5, HR 4.36, p = 0.0019) or a history of ICH (HR 3.82, p = 0.014). A trend toward a positive correlation (Pearson correlation coefficient 0.548, p < 0.0001) was found between the number of deep and subcortical dotHSs. Although a small sample size limited the power of analyses, the findings indicate that a large number of subcortical dotHSs may predict SVD recurrence.

  10. Detection of the index tumour and tumour volume in prostate cancer using T2-weighted and diffusion-weighted magnetic resonance imaging (MRI) alone.

    Science.gov (United States)

    Rud, Erik; Klotz, Dagmar; Rennesund, Kristin; Baco, Eduard; Berge, Viktor; Lien, Diep; Svindland, Aud; Lundeby, Eskild; Berg, Rolf E; Eri, Lars M; Eggesbø, Heidi B

    2014-12-01

    To examine the performance of T2-weighted (T2W) and diffusion-weighted (DW) magnetic resonance imaging (MRI) for detecting the index tumour in patients with prostate cancer and to examine the agreement between MRI and histology when assessing tumour volume (TV) and overall tumour burden. The study included 199 consecutive patients with biopsy confirmed prostate cancer randomised to MRI before radical prostatectomy from December 2009 to July 2012. MRI-detected tumours (MRTs) were ranked from 1 to 3 according to decreasing volume and were compared with histologically detected tumours (HTs) ranked from 1 to 3, with HT 1 = index tumour. Whole-mount section histology was used as a reference standard. The TVs of true-positive MRTs (MRTVs 1-3) were compared with the TVs found by histology (HTVs 1-3). All tumours were registered on a 30-sector map and by classifying each sector as positive/negative, the rate of true-positive and -negative sectors was calculated. The detection rate for the HT 1 (index tumour) was 92%; HT 2, 45%; and HT 3, 37%. The MRTV 1-3 vs the HTV 1-3 were 2.8 mL vs 4.0 mL (index tumour, P MRI detects the index tumour in 92% of cases, although MRI underestimates both TV and tumour burden compared with histology. © 2014 The Authors. BJU International © 2014 BJU International.

  11. 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

  12. 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.

  13. Diffusion-weighted whole-body magnetic resonance imaging with background body signal suppression/T2 image fusion for the diagnosis of acute cholecystitis

    Science.gov (United States)

    Tomizawa, Minoru; Shinozaki, Fuminobu; Tanaka, Satomi; Sunaoshi, Takafumi; Kano, Daisuke; Sugiyama, Eriko; Shite, Misaki; Haga, Ryouta; Fukamizu, Yoshiya; Fujita, Toshiyuki; Kagayama, Satoshi; Hasegawa, Rumiko; Shirai, Yoshinori; Motoyoshi, Yasufumi; Sugiyama, Takao; Yamamoto, Shigenori; Ishige, Naoki

    2017-01-01

    Prompt and accurate diagnosis is critical in the treatment of acute cholecystitis. Diffusion-weighted whole-body magnetic resonance imaging with background body signal suppression/T2 image fusion (DWIBS/T2) identifies areas with high signal intensity, corresponding to inflammation. In the present study, the records and images of patients with acute cholecystitis who underwent DWIBS/T2 between January 2013 and March 2014 were retrospectively analyzed. A total of 11 patients with acute cholecystitis were enrolled. In one patient, DWIBS/T2 identified a thickened wall and high signal intensity, with high signal intensity in the pericholecystic space that suggested localized peritonitis. Positive DWIBS/T2 results indicating acute cholecystitis were obtained in 10/11 patients, with a sensitivity of 90.9%. In addition, wall thickening and high signal intensity were absent in DWIBS/T2 images when wall thickening was not detected by computed tomography. Wall thickening and high signal intensity was attenuated when patients with acute cholecystitis were clinically treated. These data suggest that a thickened gallbladder wall and high signal intensity are indicative of acute cholecystitis and that DWIBS/T2 may be a useful technique in evaluating the severity of acute cholecystitis. PMID:28672991

  14. High Signal Intensity on T2-Weighted Cardiovascular Magnetic Resonance Imaging Predicts Life-Threatening Arrhythmic Events in Hypertrophic Cardiomyopathy Patients.

    Science.gov (United States)

    Hen, Yasuki; Takara, Ayako; Iguchi, Nobuo; Utanohara, Yuko; Teraoka, Kunihiko; Takada, Kaori; Machida, Haruhiko; Takamisawa, Itaru; Takayama, Morimasa; Yoshikawa, Tsutomu

    2018-02-21

    The prognostic value of high signal intensity on T2-weighted cardiovascular magnetic resonance imaging (T2 high signal) in hypertrophic cardiomyopathy (HCM) patients in a single-center cohort was investigated.Methods and Results:A total of 237 HCM patients (median age, 62 years; 143 male) underwent T2-weighted, cine and late gadolinium enhancement (LGE) imaging, and were followed (median duration, 3.4 years) for life-threatening arrhythmic events. The clinical and magnetic resonance imaging characteristics were extracted, and predictors of life-threatening arrhythmic events were assessed on multivariate analysis. LGE was present in 180 patients (75.9%). Median LGE score was 3 in a left ventricle 17-segment model. T2 high signal was present in 49 patients (20.7%). The annual events rate was significantly higher in patients with extensive LGE (score ≥4) than in those without (3.0%/year vs. 0.5%/year, P=0.011). On multivariate analysis, extensive LGE (hazard ratio, 5.650; 95% CI: 1.263-25.000, P=0.024) as an independent predictor for life-threatening arrhythmic events. In patients with extensive LGE, the annual events rate was significantly higher in patients with T2 high signal than in those without (5.8%/year vs. 0.9%/year, P=0.008). Extensive LGE was an independent predictor of life-threatening arrhythmic events in HCM patients. Furthermore, T2 high signal is useful for the risk stratification of serious arrhythmic events in patients with extensive LGE.

  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

    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.

  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

    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.

  17. 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

  18. Is the Susceptibility Vessel Sign on 3-Tesla Magnetic Resonance T2*-Weighted Imaging a Useful Tool to Predict Recanalization in Intravenous Tissue Plasminogen Activator?

    Science.gov (United States)

    Yamamoto, N; Satomi, J; Harada, M; Izumi, Y; Nagahiro, S; Kaji, R

    2016-09-01

    The aim of this study was to investigate the independent factors associated with the absence of recanalization approximately 24 h after intravenous administration of tissue-type plasminogen activator (IV TPA). The previous studies have been conducted using 1.5-Tesla (T) magnetic resonance imaging (MRI). We studied whether the characteristics of 3-T MRI findings were useful to predict outcome and recanalization after IV tPA. Patients with internal carotid artery (ICA) or middle cerebral artery (MCA) (horizontal portion, M1; Sylvian portion, M2) occlusion and treated by IV tPA were enrolled. We studied whether the presence of susceptibility vessel sign (SVS) at M1 and low clot burden score on T2*-weighted imaging (T2*-CBS) on 3-T MRI were associated with the absence of recanalization. A total of 49 patients were enrolled (27 men; mean age, 73.9 years). MR angiography obtained approximately 24 h after IV tPA revealed recanalization in 21 (42.9 %) patients. Independent factors associated with the absence of recanalization included ICA or proximal M1 occlusion (odds ratio, 69.6; 95 % confidence interval, 5.05-958.8, p = 0.002). In this study, an independent factor associated with the absence of recanalization may be proximal occlusion of the cerebral arteries rather than SVS in the MCA or low T2*-CBS on 3-T MRI.

  19. 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

  20. 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.

  1. Mucocele-like lesions of the sphenoid sinus with hypointense foci on T2-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ishibashi, T. [Dept. of Otolaryngology, Social Insurance Central General Hospital, Tokyo (Japan); Kikuchi, S. [Dept. of Otolaryngology, Tokyo Univ. Branch Hospital, Tokyo (Japan)

    2001-12-01

    Lesions limited to the sphenoid sinus are relatively rare, and are obscure with respect to symptoms and physical findings. The differential diagnosis of isolated sphenoid sinus disease includes bacterial sinusitis, fungal infection, granulomatous inflammation, mucocele, and tumors. Magnetic resonance imaging (MRI) can provide information that closely reflects the composition of the tissues, sometimes permitting differentiation between pathologically distinct lesions showing similar density by computed tomography. We describe two cases involving mucocele-like lesions of the sphenoid sinus where preoperative MRI revealed a focus of hypointensity within the lesions. In both patients the sphenoid sinus was opened by a transnasal endoscopic approach, and diseased tissue corresponding to the hypointense area was removed under direct endoscopic vision. Histopathological diagnosis revealed colonies of Aspergillus in one case and necrotic granulation tissue without fungus in the other. We concluded that MRI is a crucial part of preoperative evaluation and that the transnasal endoscopic approach represents a safe and effective method for treating nonmalignant isolated sphenoid sinus disease. (orig.)

  2. 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.)

  3. 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.

  4. High-resolution 3-dimensional T2*-weighted angiography (HR 3-D SWAN): an optimized 3-T magnetic resonance imaging sequence for targeting the subthalamic nucleus.

    Science.gov (United States)

    Lefranc, Michel; Derrey, Stéphane; Merle, Philippe; Tir, Mélissa; Constans, Jean-Marc; Montpellier, Dominique; Macron, Jean Michel; Le Gars, Daniel; Peltier, Johan; Baledentt, Olivier; Krystkowiak, Pierre

    2014-06-01

    Subthalamic nucleus deep brain stimulation (STN-DBS) is an established treatment for Parkinson's disease. To characterize an optimized magnetic resonance imaging (MRI) sequence (high-resolution 3-dimensional T2*-weighted angiography [HR 3-D SWAN]) for direct STN targeting. Sequence distortions were measured using the Leksell stereotactic phantom. Eight consecutive candidates for STN-DBS underwent HR 3-D SWAN MRI for direct identification of the 16 STN. Two senior neurosurgeons independently determined the boundaries of STN on a semiquantitative scale (ranging from 1 [identification very easy] to 4 [identification very difficult]) and the anatomic target within the nucleus. The anatomic data were compared with electrophysiological recordings (48 microrecordings). We examined the anatomic location of the active contacts on MRI. The mean distortion error over the phantom was 0.16 mm. For the 16 STNs, identification of the upper, internal, anterior, and external edges was considered to be easy (scores of 1 or 2). The distinction between the substantia nigra and the STN was rated 1 or 2 for all but 6 nuclei. In the mediolateral axis, electrophysiological recordings covered perfectly anatomic data. In the craniocaudal axis, the mean differences between the electrophysiological data and the anatomic data were 0.8 mm and 0.19 mm for the "entry" and "exit" of the STN, respectively. All active contacts were located within the STN on MRI. HR 3-D SWAN allows easy visualization of the STN. Adapted to stereotactic requirement, the sequence simplifies direct targeting in STN-DBS surgery.

  5. Targeting Accuracy of the Subthalamic Nucleus in Deep Brain Stimulation Surgery: Comparison Between 3 T T2-Weighted Magnetic Resonance Imaging and Microelectrode Recording Results.

    Science.gov (United States)

    Nowacki, Andreas; Debove, Ines; Fiechter, Michael; Rossi, Frédéric; Oertel, Markus Florian; Wiest, Roland; Schüpbach, Michael; Pollo, Claudio

    2017-08-02

    Targeting accuracy in deep brain stimulation (DBS) surgery can be defined as the level of accordance between selected and anatomic real target reflected by characteristic electrophysiological results of microelectrode recording (MER). To determine the correspondence between the preoperative predicted target based on modern 3-T magnetic resonance imaging (MRI) and intraoperative MER results separately on the initial and consecutive second side of surgery. Retrospective cohort study of 86 trajectories of DBS electrodes implanted into the subthalamic nucleus (STN) of patients with Parkinson's disease. The entrance point of the electrode into the STN and the length of the electrode trajectory crossing the STN were determined by intraoperative MER findings and 3 T T2-weighted magnetic resonance images with 1-mm slice thickness. Average difference between MRI- and MER-based trajectory lengths crossing the STN was 0.28 ± 1.02 mm (95% CI: -0.51 to -0.05 mm). There was a statistically significant difference between the MRI- and MER-based entry points on the initial and second side of surgery ( P = .04). Forty-three percent of the patients had a difference of more than ±1 mm of the MRI-based-predicted and the MER-based-determined entry points into the STN with values ranging from -3.0 to + 4.5 mm. STN MRI-based targeting is accurate in the majority of cases on the first and second side of surgery. In 43% of implanted electrodes, we found a relevant deviation of more than 1 mm, supporting the concept of MER as an important tool to guide and optimize targeting and electrode placement. Copyright © 2017 by the Congress of Neurological Surgeons

  6. 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...... superior image quality and practical advantages. Therefore, the aim was to describe the main coronary perfusion territories using CE-SSFP and T2-STIR cardiovascular magnetic resonance data in patients after acute ST-segment-elevation myocardial infarction. Methods and Results - CE-SSFP and T2-STIR data...

  7. 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)

  8. 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.)

  9. Cardiovascular magnetic resonance of the myocardium at risk in acute reperfused myocardial infarction: comparison of T2-weighted imaging versus the circumferential endocardial extent of late gadolinium enhancement with transmural projection.

    Science.gov (United States)

    Ubachs, Joey F A; Engblom, Henrik; Erlinge, David; Jovinge, Stefan; Hedström, Erik; Carlsson, Marcus; Arheden, Håkan

    2010-03-29

    In the situation of acute coronary occlusion, the myocardium supplied by the occluded vessel is subject to ischemia and is referred to as the myocardium at risk (MaR). Single photon emission computed tomography has previously been used for quantitative assessment of the MaR. It is, however, associated with considerable logistic challenges for employment in clinical routine. Recently, T2-weighted cardiovascular magnetic resonance (CMR) has been introduced as a new method for assessing MaR several days after the acute event. Furthermore, it has been suggested that the endocardial extent of infarction as assessed by late gadolinium enhanced (LGE) CMR can also be used to quantify the MaR. Hence, we sought to assess the ability of endocardial extent of infarction by LGE CMR to predict MaR as compared to T2-weighted imaging. Thirty-seven patients with early reperfused first-time ST-segment elevation myocardial infarction underwent CMR imaging within the first week after percutaneous coronary intervention. The ability of endocardial extent of infarction by LGE CMR to assess MaR was evaluated using T2-weighted imaging as the reference method. MaR determined with T2-weighted imaging (34 +/- 10%) was significantly higher (p infarction (23 +/- 12%). There was a weak correlation between the two methods (r2 = 0.17, p = 0.002) with a bias of -11 +/- 12%. Myocardial salvage determined with T2-weighted imaging (58 +/- 22%) was significantly higher (p myocardial salvage determined with endocardial extent of infarction (45 +/- 23%). No MaR could be determined by endocardial extent of infarction in two patients with aborted myocardial infarction. This study demonstrated that the endocardial extent of infarction as assessed by LGE CMR underestimates MaR in comparison to T2-weighted imaging, especially in patients with early reperfusion and aborted myocardial infarction.

  10. Comparison of two fat-suppressed magnetic resonance imaging pulse sequences to standard t2-weighted images for brain parenchymal contrast and lesion detection in dogs with inflammatory intracranial disease.

    Science.gov (United States)

    Young, Benjamin D; Mankin, Joseph M; Griffin, John F; Fosgate, Geoffrey T; Fowler, Jennifer L; Levine, Jonathan M

    2015-01-01

    T2-weighted (T2w) sequences are commonly relied upon in magnetic resonance imaging protocols for the detection of brain lesions in dogs. Previously, the effect of fluid suppression via fluid-attenuated inversion recovery (FLAIR) has been compared to T2-weighting with mixed results. Short tau inversion recovery (STIR) has been reported to increase the detection of some CNS lesions in people. The purpose of the current study was to evaluate the effect of fat suppression on brain parenchymal contrast resolution and lesion detection in dogs. We compared three sequences: T2w images, STIR, and T2w FLAIR with chemical fat suppression (T2-FLAIR-FS) in dogs with meningoencephalitis. Dogs with meningoencephalitis and dogs with idiopathic epilepsy were retrospectively identified and anonymized. Evaluators recorded the presence or absence of lesions within 12 predetermined brain regions on randomized sequences, viewing and scoring each sequence individually. Additionally, signal-to-noise ratios, contrast-to-noise ratios, and relative contrast (RC) were measured in a reference population. Short tau inversion recovery sequences had the highest RC between gray and white matter. While descriptively more lesions were identified by evaluators on T2-FLAIR-FS images, there was no statistical difference in the relative sensitivity of lesion detection between the sequences. Nor was there a statistical difference in false lesion detection within our reference population. Short tau inversion recovery may be favored for enhanced anatomic contrast depiction in brain imaging. No benefit of the inclusion of a fat-suppressed T2-FLAIR sequence was found. © 2014 American College of Veterinary Radiology.

  11. 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

  12. A novel five-category multimodal T1-weighted and T2-weighted magnetic resonance imaging-based stratification system for the selection of spinal arachnoid cyst treatment: a 15-year experience of 81 cases

    Directory of Open Access Journals (Sweden)

    Qi J

    2014-03-01

    Full Text Available Ji Qi, Jun Yang, Guihuai Wang Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China Background: Idiopathic spinal arachnoid cysts are rare cystic masses of the spinal canal generally classified as intra- or extradural, based on anatomical presentation. However, this system may not effectively indicate treatment. Objective: To investigate the incidence, resection modality, and prognosis of spinal arachnoid cyst in a 15-year case series. Patients and methods: A retrospective study was conducted in 81 spinal arachnoid cyst patients (male:female 34:47, mean age 36.5 years, age range 6–66 years classified using a novel five-category T1-weighted and T2-weighted magnetic resonance imaging (MRI classification system (intramedullary, subdural extramedullary, subdural/epidural, intraspinal epidural, or intraspinal/extraspinal. Conservative treatment failed in all patients. They underwent spinal surgery between January 1995 and December 2010 and were followed up for 69 (range 3–187 months. Performance outcomes were assessed using the Fugl-Meyer (FM scale 90 days after operation. Recurrences and deaths were recorded. Results: Subdural/epidural and intraspinal epidural cysts accounted for 66.7% (54 of 81 of patients, but exhibited relatively lower rates of postsurgical improvement using FM, with only 66.7% (36 of 54 of patients showing improvements. Excellent outcomes using the FM scale were reached in 100% (eight of eight of intramedullary, intraspinal/extraspinal, and subdural extramedullary cyst patients, 86.7% (13 of 15 of subdural extramedullary cyst patients, and 66.7% (36 of 54 of epidural intraspinal cyst patients. Conclusion: The proposed five-category multimodal MRI-based stratification system for spinal arachnoid cyst patients may more effectively allow clinicians to select the appropriate surgical intervention, and may help to predict outcomes. Keywords: spinal arachnoid cyst

  13. 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.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Mirakhur, Anirudh, E-mail: ani.mirakhur@gmail.com [Department of Diagnostic Imaging, Foothills Medical Centre, University of Calgary, Calgary (Canada); Anca, Nicoleta, E-mail: nicoletanca@gmail.com [Department of Diagnostic Imaging, Foothills Medical Centre, University of Calgary, Calgary (Canada); Mikami, Yoko, E-mail: yokomikami@gmail.com [Stephenson Cardiovascular MR Centre, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary (Canada); Merchant, Naeem, E-mail: n.merchant22@gmail.com [Department of Diagnostic Imaging, Foothills Medical Centre, University of Calgary, Calgary (Canada); Stephenson Cardiovascular MR Centre, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary (Canada)

    2013-10-01

    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.

  15. 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

  16. The value of magnetic resonance imaging for the detection of focal liver lesions using different T-2 weighted techniques: is there a consensus?

    OpenAIRE

    Palácio, Glaucia Andrade e Silva; Abbehusen, Cristiane Lima; Tiferes, Dario Ariel; D'Ippolito, Giuseppe; Szejnfeld, Jacob

    2002-01-01

    Desde o início da década de 80 a ressonância magnética vem sendo utilizada para o estudo do abdome e principalmente na detecção de nódulos hepáticos. As imagens ponderadas em T2 são as que trouxeram maior benefício quando comparadas à tomografia computadorizada com contraste. Inúmeras técnicas e seqüências de ressonância magnética ponderadas em T2 surgiram desde então, na tentativa de aumentar a eficácia diagnóstica, com menores tempos de exame. Neste sentido, foram publicados inúmeros trabal...

  17. 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.)

  18. O valor da ressonância magnética na detecção de nódulos hepáticos utilizando-se diversas técnicas ponderadas em T2: existe consenso? The value of magnetic resonance imaging for the detection of focal liver lesions using different T-2 weighted techniques: is there a consensus?

    Directory of Open Access Journals (Sweden)

    Glaucia Andrade e Silva Palácio

    2002-11-01

    Full Text Available Desde o início da década de 80 a ressonância magnética vem sendo utilizada para o estudo do abdome e principalmente na detecção de nódulos hepáticos. As imagens ponderadas em T2 são as que trouxeram maior benefício quando comparadas à tomografia computadorizada com contraste. Inúmeras técnicas e seqüências de ressonância magnética ponderadas em T2 surgiram desde então, na tentativa de aumentar a eficácia diagnóstica, com menores tempos de exame. Neste sentido, foram publicados inúmeros trabalhos demonstrando a utilidade de seqüências rápidas e ultra-rápidas, com e sem supressão de gordura, em apnéia, com sincronizador respiratório e com bobinas de sinergia, entre outros avanços tecnológicos. No entanto, não há um consenso sobre qual a técnica mais apropriada e sensível para a detecção de lesões hepáticas focais. Neste artigo fazemos uma revisão bibliográfica e análise crítica das diversas técnicas de imagens ponderadas em T2, no que diz respeito às suas sensibilidades na detecção de nódulos hepáticos.Since the early 1980's several magnetic resonance imaging pulse sequences have been developed in order to determine the optimum imaging technique for the detection and characterization of hepatic lesions. T2-weighted images play an important role in the evaluation of the liver and present equal or greater sensitivity than enhanced computed tomography for the detection of liver lesions. New techniques for obtaining T-2 weighted images have been developed in the attempt to optimize the method. These techniques have improved the image quality by shortening examination time, reducing motion artifacts, and improving contrast-to-noise ratio. The effectiveness of the different techniques (fat suppression, breath-hold, respiratory-triggered and phased-array coils has been tested in many comparative studies, although the results are controversial. In this article we review the literature and discuss the several

  19. 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.

  20. 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...

  1. Changes in susceptibility signs on serial T2*-weighted single-shot echo-planar gradient-echo images in acute embolic infarction: comparison with recanalization status on 3D time-of-flight magnetic resonance angiography

    International Nuclear Information System (INIS)

    Shinohara, Yuki; Kinoshita, Toshibumi; Kinoshita, Fumiko

    2012-01-01

    The present study compares changes in susceptibility signs on follow-up single-shot echo-planar gradient-echo T2*-weighted images (GRE-EPI) with vascular status on follow-up magnetic resonance angiography (MRA) in acute embolic infarction. Twenty consecutive patients with acute embolic infarction repeatedly underwent MR imaging including GRE-EPI and MRA using a 1.5-T MR superconducting system. All patients underwent initial MR examination within 24 h of onset and follow-up MR imaging within 1 month after onset. Changes in susceptibility signs on follow-up GRE-EPI were compatible with vascular status on follow-up MRA in 19 of the 20 patients. Susceptibility signs disappeared with complete recanalization in 13 patients, migrated with partial recanalization in 3, did not change together with the absence of recanalization in 2, and became extended together with the absence of recanalization in 1. Cerebral hemorrhage obscured susceptibility signs in the one remaining patient. Susceptibility signs on follow-up GRE-EPI can reflect changes in an acute embolus, such as recanalization or migration, in this study. Serial GRE-EPI in acute embolism complements the diagnostic certainty of MRA by directly detecting an embolus as a susceptibility sign. (orig.)

  2. Understanding the Morphological Mismatch between Magnetic Susceptibility Source and T2 Image

    Directory of Open Access Journals (Sweden)

    Zikuan Chen

    2013-01-01

    Full Text Available Background and Purpose Recent research has shown that a T2 * image (either magnitude or phase is not identical to the internal spatial distribution of a magnetic susceptibility (χ source. In this paper, we examine the reasons behind these differences by looking into the insights of T2 * -weighted magnetic resonance imaging (T2 * MRI and provide numerical characterizations of the source/image mismatches by numerical simulations. Methods For numerical simulations of T2 * MRI, we predefine a 3D χ source and calculate the complex-valued T2 * image by intravoxel dephasing in presence and absence of diffusion. We propose an empirical α-power model to describe the overall source/image transformation. For a Gaussian-shaped χ source, we numerically characterize the source/image morphological mismatch in terms of spatial correlation and FWHM (full width at half maximum. Results In theory, we show that the χ-induced fieldmap is morphologically different from the χ source due to dipole effect, and the T2 * magnitude image is related to the fieldmap by a quadratic transformation in the small phase angle regime, which imposes an additional morphological change. The numerical simulations with a Gaussian-shaped χ source show that a T2 * magnitude image may suffer an overall source/image morphological shrinkage of 20% to 25% and that the T2 * phase image is almost identical to the fieldmap thus maintaining a morphological mismatch from the χ source due to dipole effect. Conclusion The morphological mismatch between a bulk χ source and its T2 * image is caused by the 3D convolution during tissue magnetization (dipole effect, the nonlinearity of the T2 * magnitude and phase calculation, and the spin diffusion effect. In the small phase angle regime, the T2 * magnitude exhibits an overall morphological shrinkage, and the T2 * phase image suffers a dipole effect but maintains the χ-induced fieldmap morphology.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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; Estudo comparativo das sequencias rapidas ponderadas em T2, utilizando-se sincronizacao respiratoria, apneia, supressao de gordura, bobina de corpo e bobina de sinergia para a avaliacao do figado pela ressonancia magnetica

    Energy Technology Data Exchange (ETDEWEB)

    Abbehusen, Cristiane L.; D' Ippolito, Giuseppe; Palacio, Glaucia A.S.; Szejnfeld, Jacob [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Escola Paulista de Medicina (EPM). Dept. de Diagnostico por Imagem]. E-mail: cabbehusen@hotmail.com

    2003-10-01

    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)

  8. 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

  9. Detecting Acute Myocardial Infarction by Diffusion-Weighted versus T2-Weighted Imaging and Myocardial Necrosis Markers.

    Science.gov (United States)

    Jin, Jiyang; Chen, Min; Li, Yongjun; Wang, YaLing; Zhang, Shijun; Wang, Zhen; Wang, Lin; Ju, Shenghong

    2016-10-01

    We used a porcine model of acute myocardial infarction to study the signal evolution of ischemic myocardium on diffusion-weighted magnetic resonance images (DWI). Eight Chinese miniature pigs underwent percutaneous left anterior descending or left circumflex coronary artery occlusion for 90 minutes followed by reperfusion, which induced acute myocardial infarction. We used DWI preprocedurally and hourly for 4 hours postprocedurally. We acquired turbo inversion recovery magnitude T2-weighted images (TIRM T2WI) and late gadolinium enhancement images from the DWI slices. We measured the serum myocardial necrosis markers myoglobin, creatine kinase-MB isoenzyme, and cardiac troponin I at the same time points as the magnetic resonance scanning. We used histochemical staining to confirm injury. All images were analyzed qualitatively. Contrast-to-noise ratio (the contrast between infarcted and healthy myocardium) and relative signal index were used in quantitative image analysis. We found that DWI identified myocardial signal abnormity early (acute myocardial infarction and identified the infarct-related high signal more often than did TIRM T2WI: 7 of 8 pigs (87.5%) versus 3 of 8 (37.5%) ( P =0.046). Quantitative image analysis yielded a significant difference in contrast-to-noise ratio and relative signal index between infarcted and normal myocardium on DWI. However, within 4 hours after infarction, the serologic myocardial injury markers were not significantly positive. We conclude that DWI can be used to detect myocardial signal abnormalities early after acute myocardial infarction-identifying the infarction earlier than TIRM T2WI and widely used clinical serologic biomarkers.

  10. 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

  11. MR-guided sclerotherapy of low-flow vascular malformations using T2 -weighted interrupted bSSFP (T2 W-iSSFP): comparison of pulse sequences for visualization and needle guidance.

    Science.gov (United States)

    Xu, Di; Herzka, Daniel A; Gilson, Wesley D; McVeigh, Elliot R; Lewin, Jonathan S; Weiss, Clifford R

    2015-02-01

    Image-guided treatment of low-flow vascular (venous or lymphatic) malformations presents a challenging visualization problem, regardless of the imaging modality being used for guidance. The purpose of this study was to employ a new magnetic resonance imaging (MRI) sequence, T2 -weighted interrupted balanced steady-state free precession (T2 W-iSSFP), for real-time image guidance of needle insertion. T2 W-iSSFP uses variable flip angle balanced steady-state free precession (bSSFP, a.k.a. SSFP) to establish T2 -weighting and fat suppression. Swine (n = 3) and patients (n = 4, three female, all with venous malformations) were enrolled in the assessment. T2 -weighted turbo spin echo (T2 -TSE) with spectral adiabatic inversion recovery (SPAIR), SPAIR-T2 -TSE or T2 -TSE for short, was used as the reference. T2 -weighted half Fourier acquired single shot turbo spin echo (T2 -HASTE) with SPAIR (SPAIR-T2 -HASTE, T2 -HASTE for short), fat saturated bSSFP (FS-SSFP), and T2 W-iSSFP were imaged. Numeric metrics, namely, contrast-to-noise ratio (CNR) efficiency (CNR divided by the square root of acquisition time) and local sharpness (the reciprocal of edge width), were used to assess image quality. MR-guided sclerotherapy was performed on the same patients using real-time T2 W-iSSFP to guide needle insertion. Comparing the visualization of needles in the images of swine, the local sharpness (mm(-1) ) was: 0.21 ± 0.06 (T2 -HASTE), 0.48 ± 0.02 (FS-SSFP), and 0.49 ± 0.03 (T2 W-iSSFP). T2 W-iSSFP is higher than T2 -HASTE (P W-iSSFP). T2 W-iSSFP is higher than FS-SSFP (P W-iSSFP was 2.5-3.5 frames per second. All MR-guided sclerotherapy procedures were successful, with all needles (six punctures) placed in the targets. T2 W-iSSFP provides effective lesion identification and needle visualization. This new pulse sequence can be used for MR-guided sclerotherapy of low-flow vascular malformations. It may have potential use in other MR-guided procedures where heavily T2 -weighted real

  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. 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

  14. Texture-based quantification of lumbar intervertebral disc degeneration from conventional T2-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Michopoulou, Sofia; Speller, Robert; Todd-Pokropek, Andrew (Dept. of Medical Physics and Bioengineering, University College London (United Kingdom)), e-mail: s.michopoulou@ucl.ac.uk; Costaridou, Lena (Dept. of Medical Physics, School of Medicine, Univ. of Patras (Greece)); Vlychou, Marianna (Dept. of Radiology, Univ. Hospital of Larissa, Univ. of Thessaly (Greece))

    2011-02-15

    Background: Disc degeneration quantification is important for monitoring the effects of new therapeutic methods, such as cell and growth factor therapy. Magnetic resonance (MR) image texture reflects biochemical and structural tissue properties and has been used for differentiating between normal and pathological status in a variety of medical applications. Purpose: To investigate the suitability of textural descriptors for the quantification of intervertebral disc degeneration using conventional T2-weighted magnetic resonance images of the lumbar spine. Material and Methods:: A 3 Tesla scanner was used, and conventional T2- weighted MR images were obtained, and a total of 255 lumbar discs were analyzed. An atlas-based method was used for segmenting the disc regions from the images. A set of first and second order statistics describing texture of each region were calculated. The validity and reliability of these descriptors for disc degeneration severity quantification was tested through their correlation with patient age and qualitative clinical grading of degeneration severity. Texture quantification results were compared to a widely accepted method for disc degeneration quantification based on the measurement of disc's mean signal intensity. Results: Out of the set of texture descriptors tested, two descriptors quantifying image intensity inhomogeneity, i.e. the grey level standard deviation and co-occurrence derived sum of squares displayed the strongest association to patient age and clinical grading of disc degeneration severity (P < 0.001). This is attributed to these inhomogeneity descriptors' capability to capture the progressive loss of nucleus-annulus distinction in the degenerative progress. Statistical analysis indicates that these descriptors can effectively separate between early stages of degeneration. Quantitative measurements are highly repeatable (intraclass correlation >0.98). Conclusion: Inhomogeneity descriptors could be a valuable

  15. Dynamics of dot-like hemosiderin spots on T2*-weighted MRIs associated with stroke recurrence.

    Science.gov (United States)

    Imaizumi, Toshio; Honma, Toshimi; Horita, Yoshifumi; Chiba, Masahiko; Kawamura, Maiko; Miyata, Kei; Kohama, Ikuhide; Niwa, Jun

    2007-07-01

    Dot-like low-intensity spots (dot-like hemosiderin spots: dotHSs) on gradient echo T2*-weighted (-w) brain magnetic resonance imaging (MRIs) are frequently associated with cerebral small vessel disease (SVD), including deep intracerebral hemorrhages and lacunar infarctions. This study investigated how numbers of newly appeared dotHSs contribute to recurrent SVD. We prospectively analyzed numbers of newly appeared dotHSs in 12 patients with prior SVD (8 males, 4 females; mean 67.6 +/- 10.7 years old) readmitted with recurring SVD between October 2001 and March 2003. Numbers of appeared dotHSs per year were counted on T2*-w MRI scans after SVD recurrence and compared to previous MRIs. Seventy-one outpatients (35 males, 36 females; mean 64.3 +/- 9.6 years old) with histories of intracerebral hemorrhages (ICH) that came to the hospital during the study period served as controls. The hazard ratio (HR) for recurrence was estimated from a multivariate logistic regression model, using the number of appeared dotHSs (per year) and other risk factors. Multivariate analyses revealed that an elevated rate of recurrence was found in patients with substantial numbers of appeared dotHSs (>or=5/year) (HR, 7.34; P= 0.0008). We also analyzed factors associated with the numbers of appeared dotHSs. A number of appeared dotHSs (>or=5/year) was significantly and independently associated with the initial number of dotHSs (>or=10) on T2*-w MRIs following the first SVD (HR, 18.6; P= 0.0001). Though a small sample size limited the power of our analyses, our findings suggest that a number of newly appeared dotHSs may be associated with SVD recurrence.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. Diagnosis of pituitary microadenoma : significance of T2-weighted MR image

    Energy Technology Data Exchange (ETDEWEB)

    Ra, Won Kyun; Lee, Yul; Ko, Eun Young; Lee, Kyung Won; Yang, Ik; Chung, Soo Young; Shim, Jeong Won [Kangnam Sacred Heart Hospital, Hallym Univ., Seoul (Korea, Republic of)

    1999-04-01

    To evaluate the significance of T2-weighted MR imaging(T2WI) in the diagnosis of pituitary microadenoma. We retrospectively evaluated the MR imaging findings of 30 cases of pituitary microadenoma. Diagnosis was made on the basis of surgery, serum hormonal level, and the presence of mass lesion on MR (T1WI and T2WI), and conventional as well as dynamic contrast enhanced T1WI images were obtained. In each MR sequence, signal intensity and detectability of the tumor were evaluated. We also determined whether diagnosis was possible on both T1WI and T2WI. In eight cases, histopathologic findings (cellularity, fibrosis, and cystic change) were correlated with T2 signal intensity of the tumor. T2WI, T1WI, and dynamic and conventional enhanced T1WI detected the tumor in 21 cases (70%), 21 cases (70%), 28 cases (93.3%), and 22 cases (73.3%), respectively. On T2WI, pituitary microadenomas showed a high signal in 18 cases (60%), an iso-signal in nine (30%), and a low signal in three (10%) compared with normal pituitary gland. In 20 cases (66.7%), diagnosis of pituitary microadenoma was possible on both T1WI and T2WI, but in one case, the tumor was detected only on T2WI. Three cases with fibrosis, as seen on histopathologic examination showed an iso or low signal on T2WI. T2WI is useful in the diagnosis of pituitary microadenoma Decreased signal intensity on T2WI may suggest fibrosis.

  1. 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

  2. 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.

  3. 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.)

  4. Diagnosis of ectopic pregnancy with MRI. Efficacy of T2*-weighted imaging

    International Nuclear Information System (INIS)

    Yoshigi, Jun; Kitagaki, Hajime; Yashiro, Naobumi; Kinoshita, Takahiro; O'uchi, Toshihiro

    2006-01-01

    The purpose of this study was to assess MRI in diagnosing ectopic pregnancy (EP), emphasizing T 2 * -weighted imaging (WI) efficacy. This is a prospective study of 24 female patients (16 to 41 years, average 29.9) clinically suspected of EP from April 1999 to June 2001. Eighteen had minimal vaginal bleeding and slight abdominal pain. All had positive pregnancy tests, and sonography showed no intrauterine pregnancy despite estimated gestational age of embryos and/or high concentrations of human chorionic gonadotrophin. MRI was performed with a 1.5T imager (Siemens, Vision VB33A) with a body-array coil. T 2 -WI (HASTE), T 1 -WI (2D FLASH), and T 2 * -WI (2D FLASH) were obtained without contrast. T 2 -WI was routinely obtained in 3 directions. T 2 * -WI orientation was determined based on the T 2 -WI. One of 4 radiologists with experience interpreting abdominal MR images interpreted images based on transvaginal ultrasonography (TVUS) and laboratory results. Abnormal adnexal mass with remarkable low signal area on T 2 * -WI was diagnosed as EP. We diagnosed 19 cases as EP. Tubectomy in eighteen and abdominal total hysterectomy in one confirmed diagnosis. In one undergoing diagnostic laparoscopy, EP was denied. In 5 cases diagnosed negative based on the above criterion, no mass was detected in three, and no area of low signal was recognized on T 2 * -WI in the masses in two. EP was denied in four of five, and in one of the five, who underwent tubectomy, EP without bleeding was diagnosed. All EP were tubal pregnancies at final diagnosis, 19 were ampullar pregnancies and one, interstitial. Using MRI to diagnose EP, with T 2 * -WI as a key diagnostic factor, sensitivity was 95%, specificity 100%, and accuracy 96%. MRI using T 2 * -WI is a sensitive, specific, and accurate method to evaluate EP. T 2 * -WI is highly accurate for detecting and diagnosing EP because of its sensitivity to fresh hematoma. (author)

  5. Intracellular lipid in papillary renal cell carcinoma (pRCC): T2 weighted (T2W) MRI and pathologic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Schieda, Nicola; Van der Pol, Christian B.; Moosavi, Bardia; McInnes, Matthew D.F. [The Ottawa Hospital, The University of Ottawa, Department of Medical Imaging, Ottawa, Ontario (Canada); Mai, Kien T.; Flood, Trevor A. [The Ottawa Hospital, The University of Ottawa, Department of Anatomical Pathology, Ottawa, Ontario (Canada)

    2015-07-15

    To evaluate if pRCCs demonstrate intracellular lipid (i-lipid) at chemical-shift (CS) MRI, and assess T2W-MRI and pathologic characteristics. Sixty-two patients with a pRCC diagnosis underwent MRI over 11 years (IRB-approved). Two radiologists independently assessed for presence of i-lipid on CS-MRI and homogeneity on T2W-MRI. Inter-observer agreement was assessed via an intraclass correlation and results were compared using the Chi-square test. Discordant cases were reviewed to establish consensus. T2W SI-ratios (SI.tumor/SI.kidney) and CS-SI index were compared using independent t-tests and Spearman correlation. Two pathologists re-evaluated the histopathology. Nine of the 62 pRCCs (14.5 %) demonstrated i-lipid; agreement was moderate (ICC = 0.63). Pathology review depicted clear cells in four tumours and foamy histiocytes in five tumours. 25.8-35.4 % (ICC = 0.65) of tumours were homogeneous on T2W-MRI. No pRCC with i-lipid was considered homogeneous (p = 0.01-0.04). Overall, T2W SI-ratio and CS-SI index were 0.89 (±0.29) and -3.63 % (-7.27 to 11.42). pRCC with i-lipid had significantly higher T2W SI-ratio (p = 0.003). There was a correlation between the CS-SI index and T2W SI-ratio, (r = 0.44, p < 0.001). Intracellular lipid is uncommonly detected in pRCCs due to clear cell changes and foamy histiocytes. These tumours are associated with heterogeneously-increased SI in T2W-MRI. (orig.)

  6. Intramedullary high intensity lesion on T2-weighted MR images in compressive cervical myelopathy

    Energy Technology Data Exchange (ETDEWEB)

    Kameyama, Takashi; Mizuno, Tetsuya; Yanagi, Tsutomu; Yasuda, Takeshi; Hirose, Yoshikiyo (Nagoya Daini Red Hospital (Japan))

    1991-11-01

    Magnetic resonance (MR) imaging was performed in 147 patients with compressive lesion of the cervical spinal canal. Intramedullary high intensity lesions were observed on T2-weighted or proton density spin-echo images in patients with cervical spondylotic myelopathy (20.0%) and ossification of the posterior longitudinal ligament of the cervical spine (25.7%), while such signal abnormality was not found in patients with cervical spondylotic radiculopathy. Frequency of this finding was proportional to clinical severity of myelopathy and degree of spinal cord compression. The pathophysiological basis of such signal abnormality was presumed to vary from acute edema to chronic myelomalacia. In most cases showing intramedullary high intensity lesion, the spinal cord was compressed at multiple levels, but the high intensity was usually found at a signal level where the compression was maximum. There was a good correlation between the neurological level and the high intensity level on MR images. Thus, the intramedullary lesion on MR images is considered to be the main site of lesion responsible for the neurological symptoms. (author).

  7. Intramedullary high intensity lesion on T2-weighted MR images in compressive cervical myelopathy

    International Nuclear Information System (INIS)

    Kameyama, Takashi; Mizuno, Tetsuya; Yanagi, Tsutomu; Yasuda, Takeshi; Hirose, Yoshikiyo

    1991-01-01

    Magnetic resonance (MR) imaging was performed in 147 patients with compressive lesion of the cervical spinal canal. Intramedullary high intensity lesions were observed on T2-weighted or proton density spin-echo images in patients with cervical spondylotic myelopathy (20.0%) and ossification of the posterior longitudinal ligament of the cervical spine (25.7%), while such signal abnormality was not found in patients with cervical spondylotic radiculopathy. Frequency of this finding was proportional to clinical severity of myelopathy and degree of spinal cord compression. The pathophysiological basis of such signal abnormality was presumed to vary from acute edema to chronic myelomalacia. In most cases showing intramedullary high intensity lesion, the spinal cord was compressed at multiple levels, but the high intensity was usually found at a signal level where the compression was maximum. There was a good correlation between the neurological level and the high intensity level on MR images. Thus, the intramedullary lesion on MR images is considered to be the main site of lesion responsible for the neurological symptoms. (author)

  8. Dynamic characteristics of T2*-weighted signal in calf muscles of peripheral artery disease during low-intensity exercise.

    Science.gov (United States)

    Li, Zhijun; Muller, Matthew D; Wang, Jianli; Sica, Christopher T; Karunanayaka, Prasanna; Sinoway, Lawrence I; Yang, Qing X

    2017-07-01

    To evaluate the dynamic characteristics of T2* -weighted signal change in exercising skeletal muscle of healthy subjects and peripheral artery disease (PAD) patients under a low-intensity exercise paradigm. Nine PAD patients and nine age- and sex-matched healthy volunteers underwent a low-intensity exercise paradigm while magnetic resonance imaging (MRI) (3.0T) was obtained. T2*-weighted signal time-courses in lateral gastrocnemius, medial gastrocnemius, soleus, and tibialis anterior were acquired and analyzed. Correlations were performed between dynamic T2*-weighted signal and changes in heart rate, mean arterial pressure, leg pain, and perceived exertion. A significant signal decrease was observed during exercise in soleus and tibialis anterior of healthy participants (P = 0.0007-0.04 and 0.001-0.009, respectively). In PAD, negative signals were observed (P = 0.008-0.02 and 0.003-0.01, respectively) in soleus and lateral gastrocnemius during the early exercise stage. Then the signal gradually increased above the baseline in the lateral gastrocnemius during and after exercise in six of the eight patients who completed the study. This signal increase in patients' lateral gastrocnemius was significantly greater than in healthy subjects' during the later exercise stage (two-sample t-tests, P = 0.001-0.03). Heart rate and mean arterial pressure responses to exercise were significantly higher in PAD than healthy subjects (P = 0.036 and 0.008, respectively) and the patients experienced greater leg pain and exertion (P = 0.006 and P = 0.0014, respectively). During low-intensity exercise, there were different dynamic T2*-weighted signal behavior in the healthy and PAD exercising muscles. 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:40-48. © 2016 International Society for Magnetic Resonance in Medicine.

  9. Detection of hemosiderin deposition by T2*-weighted MRI after subarachnoid hemorrhage.

    Science.gov (United States)

    Imaizumi, Toshio; Chiba, Masahiko; Honma, Toshimi; Niwa, Jun

    2003-07-01

    Subarachnoid hemorrhage (SAH) is very difficult to diagnose several months after its onset. We thus investigated subarachnoid hemosiderin deposition well after SAH by T2*-weighted MRI, a sensitive method for hemosiderin detection. To investigate how hemosiderin deposition as confirmed by T2*-weighted MRI contributes to the determination of prior SAH and how the extent of hemosiderin deposition is associated with a number of clinical factors, we retrospectively analyzed 58 patients >3 months after SAH associated with ruptured aneurysms. We also investigated 209 healthy volunteers as controls. T2*-weighted MRI demonstrated subarachnoid hemosiderin deposition in 72.4% of the SAH patients, whereas no deposition was seen in the healthy volunteer group. The hemosiderin was preferentially deposited in the subarachnoid space near a ruptured aneurysm. Odds ratios (ORs) were estimated from logistic regression analyses correlating hemosiderin deposition with other factors. Age (>or=54 years) (OR, 5.1; 95% CI, 1.03 to 25.0; P=0.046), Fisher grade 3 on initial CT (OR, 8.0; 95% CI, 1.26 to 50.4; P=0.027), and Karnofsky Scale score hemosiderin deposition levels. T2*-weighted MRI is an effective means of diagnosing prior SAH and may also reveal the location of a ruptured aneurysm. The extent of hemosiderin deposition was significantly associated with several factors, including age, CT findings, and poor prognosis.

  10. 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)

  11. 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)

  12. 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.)

  13. Signal intensity in T2' magnetic resonance imaging is related to brain glioma grade

    Energy Technology Data Exchange (ETDEWEB)

    Saitta, Laura; Castellan, Lucio [San Martino Hospital, Department of Diagnostic and Interventional Neuroradiology, Genoa (Italy); Heese, Oliver; Westphal, Manfred [UKE, Department of Neurosurgery, Hamburg (Germany); Foerster, Ann-Freya; Siemonsen, Susanne; Fiehler, Jens; Goebell, Einar [University Medical Center Hamburg-Eppendorf (UKE), Department of Diagnostic and Interventional Neuroradiology, Hamburg (Germany); Matschke, Jakob [UKE, Department of Neuropathology, Hamburg (Germany)

    2011-05-15

    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.)

  14. 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)

  15. 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.

  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-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.)

  18. 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.)

  19. 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

  20. Whole brain myelin mapping using T1- and T2-weighted MR imaging data.

    Science.gov (United States)

    Ganzetti, Marco; Wenderoth, Nicole; Mantini, Dante

    2014-01-01

    Despite recent advancements in MR imaging, non-invasive mapping of myelin in the brain still remains an open issue. Here we attempted to provide a potential solution. Specifically, we developed a processing workflow based on T1-w and T2-w MR data to generate an optimized myelin enhanced contrast image. The workflow allows whole brain mapping using the T1-w/T2-w technique, which was originally introduced as a non-invasive method for assessing cortical myelin content. The hallmark of our approach is a retrospective calibration algorithm, applied to bias-corrected T1-w and T2-w images, that relies on image intensities outside the brain. This permits standardizing the intensity histogram of the ratio image, thereby allowing for across-subject statistical analyses. Quantitative comparisons of image histograms within and across different datasets confirmed the effectiveness of our normalization procedure. Not only did the calibrated T1-w/T2-w images exhibit a comparable intensity range, but also the shape of the intensity histograms was largely corresponding. We also assessed the reliability and specificity of the ratio image compared to other MR-based techniques, such as magnetization transfer ratio (MTR), fractional anisotropy (FA), and fluid-attenuated inversion recovery (FLAIR). With respect to these other techniques, T1-w/T2-w had consistently high values, as well as low inter-subject variability, in brain structures where myelin is most abundant. Overall, our results suggested that the T1-w/T2-w technique may be a valid tool supporting the non-invasive mapping of myelin in the brain. Therefore, it might find important applications in the study of brain development, aging and disease.

  1. Dynamic T2-mapping during magnetic resonance guided high intensity focused ultrasound ablation of bone marrow

    Science.gov (United States)

    Waspe, Adam C.; Looi, Thomas; Mougenot, Charles; Amaral, Joao; Temple, Michael; Sivaloganathan, Siv; Drake, James M.

    2012-11-01

    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 (<1°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 T2, since T2 increases linearly in fat during heating. T2-mapping using dual echo times during a dynamic turbo spin-echo pulse sequence enabled rapid measurement of T2. Calibration of T2-based thermal maps involved heating the marrow in a bovine femur and simultaneously measuring T2 and temperature with a thermocouple. A positive T2 temperature dependence in bone marrow of 20 ms/°C was observed. Dynamic T2-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. Acute versus Chronic Myocardial Infarction: Diagnostic Accuracy of Quantitative Native T1 and T2 Mapping versus Assessment of Edema on Standard T2-weighted Cardiovascular MR Images for Differentiation.

    Science.gov (United States)

    Tahir, Enver; Sinn, Martin; Bohnen, Sebastian; Avanesov, Maxim; Säring, Dennis; Stehning, Christian; Schnackenburg, Bernhard; Eulenburg, Christine; Wien, Joshua; Radunski, Ulf K; Blankenberg, Stefan; Adam, Gerhard; Higgins, Charles B; Saeed, Maythem; Muellerleile, Kai; Lund, Gunnar K

    2017-10-01

    Purpose To analyze the diagnostic accuracy of native T1 and T2 mapping compared with visual and quantitative assessment of edema on T2-weighted cardiac magnetic resonance (MR) images to differentiate between acute and chronic myocardial infarction. Materials and Methods This study had institutional ethics committee approval. Written informed consent was obtained from 67 consecutive patients (57 years ± 12; 78% men) with a first acute myocardial infarction, who were prospectively enrolled between April 2011 and June 2015. Four serial 1.5-T MR imaging examinations were performed at 8 days ± 5, 7 weeks ± 2, 3 months ± 0.5, and 6 months ± 1.4 after infarction and included T2-weighted, native T1/T2 mapping, and late gadolinium enhancement MR imaging. Complete follow-up data were obtained in 42 patients. Regional native T1/T2 relaxation time, T2-weighted ratio, and extracellular volume were serially measured in infarcted and remote myocardium. Receiver operating characteristic (ROC) analysis was used to determine the diagnostic accuracy of the MR imaging parameters for discriminating between acute and chronic myocardial infarction. Results Native T1 of infarcted myocardium decreased from 1286 msec ± 99 at baseline to 1077 msec ± 50 at 6 months (P acute and chronic myocardial infarction. Visual analysis of the presence of edema at standard T2-weighted cardiac MR imaging resulted in an inferior AUC of 0.863 (P infarcted myocardium are excellent discriminators between acute and chronic myocardial infarction and are superior to all other MR imaging parameters. Online supplemental material is available for this article.

  3. MR fetography using heavily T2-weighted sequences: Comparison of thin- and thick-slab acquisitions

    Energy Technology Data Exchange (ETDEWEB)

    Huisman, Thierry A.G.M. [Department of Diagnostic Imaging, University Children' s Hospital Zurich (Switzerland); Division Pediatric Radiology, Johns Hopkins Hospital, Baltimore (United States)], E-mail: thuisma1@jhmi.edu; Solopova, Alina [Department of Diagnostic Imaging, University Children' s Hospital Zurich (Switzerland)

    2009-09-15

    Purpose: To evaluate the use of MR-fetography sequences in identifying the major fetal structures and to compare thick- and thin-slab acquisitions for their diagnostic value. Materials and methods: Twenty-one consecutive, pregnant women with suspected fetal pathology underwent fetal magnetic resonance imaging (MRI) using a 1.5 T MRI unit. Heavily T2-weighted, single-shot fast spin-echo (SSFSE) sequences with a long echo train (MR-fetography) were acquired in a thick- and thin-slab modus. Thick- and thin-slab acquisitions were reviewed by two experienced radiologists with regard to the overall image quality and landmark anatomical structures (spinal canal, spinal cord, posterior fossa, cerebellum, brainstem, basal cisterns, stomach, urinary bladder and umbilical cord according to a three-scale grading system (good, moderate and poor). Visibility scores were calculated and compared between both sequences. Results: Overall image quality was graded good in 76.2%, moderate in 19.0% and poor in 4.8% for thick-slab images and good in 81%, moderate in 14.3% and poor in 4.8% for thin-slab images. The visibility scores of the thick/thin-slab images for evaluation of the main fetal structures were as follows: for the spinal canal 2.8 {+-} 0.4/2.9 {+-} 0.54 (p > 0.05), spinal cord 2.4 {+-} 0.75/2.7 {+-} 0.66 (p > 0.05), posterior fossa components (cerebellum, brainstem and basal cisterns) 2.4 {+-} 0.68/2.8 {+-} 0.54; 2.4 {+-} 0.67/2.7 {+-} 0.66; 2.5 {+-} 0.51/2.7 {+-} 0.56 (p < 0.05), stomach 2.8 {+-} 0.44/2.9 {+-} 0.48 (p > 0.05), urinary bladder 2.8 {+-} 0.51/2.8 {+-} 0.54 (p > 0.05) and umbilical cord 2.9 {+-} 0.30/2.6 {+-} 0.60 (p < 0.05). Conclusion: Heavily T2-weighted MR-fetography renders a quick overview of fetal contours, fetal position, amount of amniotic fluid and integrity and presence of several major fluid containing structures. Thick- and thin-slab acquisitions render complementary information. Thick-slab images display the entire fetus in one projection while

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

    Science.gov (United States)

    Özmen, Evrim; Algın, Oktay; Evrimler, Şehnaz; Arslan, Halil

    2016-05-01

    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. 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. Diagnostic accuracy study. 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. 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. We suggest that obtaining of contrast enhanced MRC sequences in addition to the T2w-MRCP can be useful in the diagnosis of many diseases in relation with biliary tree.

  5. 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)

  6. MR fetography using heavily T2-weighted sequences: comparison of thin- and thick-slab acquisitions.

    Science.gov (United States)

    Huisman, Thierry A G M; Solopova, Alina

    2009-09-01

    To evaluate the use of MR-fetography sequences in identifying the major fetal structures and to compare thick- and thin-slab acquisitions for their diagnostic value. Twenty-one consecutive, pregnant women with suspected fetal pathology underwent fetal magnetic resonance imaging (MRI) using a 1.5 T MRI unit. Heavily T2-weighted, single-shot fast spin-echo (SSFSE) sequences with a long echo train (MR-fetography) were acquired in a thick- and thin-slab modus. Thick- and thin-slab acquisitions were reviewed by two experienced radiologists with regard to the overall image quality and landmark anatomical structures (spinal canal, spinal cord, posterior fossa, cerebellum, brainstem, basal cisterns, stomach, urinary bladder and umbilical cord according to a three-scale grading system (good, moderate and poor). Visibility scores were calculated and compared between both sequences. Overall image quality was graded good in 76.2%, moderate in 19.0% and poor in 4.8% for thick-slab images and good in 81%, moderate in 14.3% and poor in 4.8% for thin-slab images. The visibility scores of the thick/thin-slab images for evaluation of the main fetal structures were as follows: for the spinal canal 2.8+/-0.4/2.9+/-0.54 (p>0.05), spinal cord 2.4+/-0.75/2.7+/-0.66 (p>0.05), posterior fossa components (cerebellum, brainstem and basal cisterns) 2.4+/-0.68/2.8+/-0.54; 2.4+/-0.67/2.7+/-0.66; 2.5+/-0.51/2.7+/-0.56 (p0.05), urinary bladder 2.8+/-0.51/2.8+/-0.54 (p>0.05) and umbilical cord 2.9+/-0.30/2.6+/-0.60 (pslab acquisitions render complementary information. Thick-slab images display the entire fetus in one projection while thin-slab images provide more detailed anatomical information. The short imaging time usually allows measuring both thick- and thin-slab images. MR-fetography is as a helpful addition to conventional fetal MRI. MR-fetography should not be viewed as a single, stand alone sequence but as a supporting fast MR sequence in a well-designed multisequence fetal MRI protocol

  7. 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)

  8. An intracranial aspergilloma with low signal on T2-weighted images corresponding to iron accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, K. [Dept. of Radiology, Kyoto Prefectural Univ. of Medicine (Japan); Dept. of Radiology, Univ. of Maryland Medical Center, Baltimore MD (United States); Zoarski, G.H.; Rothman, M.I.; Zagardo, M.T. [Dept. of Radiology, Univ. of Maryland Medical Center, Baltimore MD (United States); Nishimura, T. [Dept. of Radiology, Kyoto Prefectural Univ. of Medicine (Japan); Sun, C.C.J. [Dept. of Pathology, Univ. of Maryland Medical Center, Baltimore MD (United States)

    2001-07-01

    We present a case of cerebral aspergillosis in an immunocompetent patient. The MRI signal characteristics were compared with the histologic findings. Irregular low-signal zones were demonstrated between the wall of the abscess and the central necrosis on T2-weighted images; the pathology specimen revealed concentrated iron in these transitional zones but no hemosiderin. Iron is an essential element for the growth of fungal hyphae. The low-signal zones may represent the areas where there was active proliferation of aspergillus, and the unique location of the low signal may be a helpful imaging characteristic for the diagnosis of an aspergillus abscess. (orig.)

  9. 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

  10. 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.

  11. 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

  12. 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.)

  13. Signal void dots on T2-weighted brain MR imaging: correlation with hypertensive brain lesions

    International Nuclear Information System (INIS)

    Yoo, Dong Soo; Jeong, Chun Keun; Kim, Sang Joon; Lee, Young Seok; Kim, Jae Il; Kwon, Ho Jang

    1998-01-01

    To evaluate the relationship of signal void dots seen on T2-weighted images with hypertension, hypertensive intracerebral hemorrhage and infarction. MR images of 73 consecutive patients with signal void dots on T2-weighted images were reviewed. Seventy-three randomly selected age-matched patients without signal void dot lesion were also reviewed. We evaluated 1) the location and number of signal void dots;2) the frequency of hypertension among patients and controls; 3) the frequency of associated brain parenchymal abnormalities (hypertensive intracerebra hemorrhage, microangiopathy and infarction) in both groups; 4) the relationship between the number of signal void dots and associated brain lesions in the patient group. Signal void dots numbered 1-50(average, 12), and were found mostly in the thalamus, basal ganglis, and the pons. Hypertension(97.1%), hypertensive ICH(43.8%) and microangiopathy(96%) were frequent in patients with signal void dots, the number of which correlated with the severity of microangiopathy. Infarction(13.7%), however, did not correlate with dots. Signal void dots correlate closely with hypertension, hypertensive ICH, and microangiopathy. They may indicate hypertensive brain change.=20

  14. 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% .

  15. MR imaging finding of synovial sarcoma: emphasis on signal characteristics on T2-weighted images

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyoung Won; Jung, Hye Weon; Cho, So Yeon; Han, Moon Hee; Im, Jung Gi; Chang, Kee Hyun; Kang, Heung Sik [Seoul National University, Seoul (Korea, Republic of). Coll. of Medicine

    1998-01-01

    To determine the MR imaging findings of synovial sarcoma, with emphasis on the signal characteristics of pathologically correlated T2-weighted images. Necrosis, cystic change or hemorrhage was suggested in 11 cases, ten of which showed triple signal intensity, and in all cases, was pathologically confirmed. Fluid-fluid levels were found in three cases and internal septa in ten. In four cases, maximum diameter was less than 5 cm, and in nine, was greater than this. No mass was detected in one case. The tumor was located in the low extremity(n=9), pelvic girdle and hip joint area(n=2), scapular (n=1), shoulder joint area(n=1), and scalp(n=1). Eleven cases showed a relatively well-defined margin and nine showed lobulation. Except in the area of necrosis and cystic change, the pattern of contrast enhancement was diffuse and inhomogeneous. Bony invasion was detected in two cases, neurovascular encasement in four, calcification in four, and joint capsule invasion in four. On T2-weighted images, synovial sarcoma frequently showed triple signal intensity and internal septa with fluid-fluid levels: this was induced by cystic changes due to necrosis and hemorrhage. (author). 13 refs., 2 figs.

  16. Volumetric T1 and T2 magnetic resonance brain toolkit for relaxometry mapping simulation

    Directory of Open Access Journals (Sweden)

    Antonio Carlos da Silva Senra Filho

    Full Text Available Abstract Introduction Relaxometry images are an important magnetic resonance imaging (MRI technique in the clinical routine. Many diagnoses are based on the relaxometry maps to infer abnormal state in the tissue characteristic relaxation constant. In order to study the performance of these image processing approaches, a controlled simulated environment is necessary. However, a simulated relaxometry image tool is still lacking. This study proposes a computational anatomical brain phantom for MRI relaxometry images, which aims to offer an easy and flexible toolkit to test different image processing techniques, applied to MRI relaxometry maps in a controlled simulated environment. Methods A pipeline of image processing techniques such as brain extraction, image segmentation, normalization to a common space and signal relaxation decay simulation, were applied to a brain structural ICBM brain template, on both T1 and T2 weighted images, in order to simulate a volumetric brain relaxometry phantom. The FMRIB Software Library (FSL toolkits were used here as the base image processing needed to all the relaxometry reconstruction. Results All the image processing procedures are performed using automatic algorithms. In addition, different artefact levels can be set from different sources such as Rician noise and radio-frequency inhomogeneity noises. Conclusion The main goal of this project is to help researchers in their future image processing analysis involving MRI relaxometry images, offering reliable and robust brain relaxometry simulation modelling. Furthermore, the entire pipeline is open-source, which provides a wide collaboration between researchers who may want to improve the software and its functionality.

  17. 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.

  18. Assessment of the diagnostic accuracy of T2*-weighted MR imaging for identifying hepatocellular carcinoma with liver explant correlation

    International Nuclear Information System (INIS)

    Hardie, Andrew D.; Nance, John W.; Boulter, Daniel J.; Kizziah, Michael K.

    2011-01-01

    Background: T2*-weighted MRI may represent a novel method for identifying hepatocellular carcinoma (HCC). The goal of this study was to assess the diagnostic accuracy of T2*-weighted MRI for HCC with liver explant correlation. Materials and methods: A retrospective review identified 25 patients who had undergone liver transplantation with pre-operative T2*-weighted MRI. All patients had Child's-Pugh A (9), B (9), or C (7) liver disease with 13 transplanted for liver dysfunction and 12 for HCC. The T2*-weighted images were interpreted by 2 blinded, independent observers and the results compared with the explanted specimens. Sensitivity and specificity of T2*-weighted MRI for the identification of HCC was assessed. Results: By pathology, 16 HCC (mean largest diameter 2.1 cm; range 0.9–3.6 cm) were identified in 14 patients. Reader 1 had a sensitivity of 69% (95% confidence interval 41–88%) and a specificity of 100% (68–100%). Reader 2 had a sensitivity of 56% (31–79%) and a specificity of 100% (68–100%). There was a very good inter-observer agreement (kappa = 0.84). Conclusion: T2*-weighted MRI had a moderate sensitivity for identifying HCC but had an excellent specificity. A T2*-weighted MR sequence may be a useful component of a liver MRI protocol due to its high specificity for HCC, and may be particularly useful in patients unable to undergo gadolinium enhanced MRI.

  19. 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.

  20. Quantitative analyses of T2-weighted MRI as a potential marker for response to somatostatin analogs in newly diagnosed acromegaly.

    Science.gov (United States)

    Heck, Ansgar; Emblem, Kyrre E; Casar-Borota, Olivera; Bollerslev, Jens; Ringstad, Geir

    2016-05-01

    In growth hormone (GH)-producing adenomas, T2-weighted MRI signal intensity is a marker for granulation pattern and response to somatostatin analogs (SSA). Prediction of treatment response is necessary for individualized treatment, and T2 intensity assessment might improve preoperative classification of somatotropinomas. The objectives of this study are (I) to explore the feasibility of quantitative T2-weighted MRI histogram analyses in newly diagnosed somatotroph adenomas and their relation to clinical and histological parameters and (II) to compare the quantitative method to conventional, visual assessment of T2 intensity. The study was a retrospective cohort study of 58 newly diagnosed patients. In 34 of these, response to primary SSA treatment after median 6 months was evaluated. Parameters from the T2 histogram analyses (T2 intensity ratio and T2 homogeneity ratio) were correlated to visually assessed T2 intensity (hypo-, iso-, hyperintense), baseline characteristics, response to SSA treatment, and histological granulation pattern (anti-Cam5.2). T2 intensity ratio was lowest in the hypointense tumors and highest in the hyperintense tumors (0.66 ± 0.10 vs. 1.07 ± 0.11; p ratio correlated with adenoma size reduction (r = -0.45; p = 0.008). Sparsely granulated adenomas had a higher T2 intensity than densely or intermediately granulated adenomas. T2 histogram analyses are an applicable tool to assess T2 intensity in somatotroph adenomas. Quantitatively assessed T2 intensity ratio in GH-producing adenomas correlates with conventional assessment of T2 intensity, baseline characteristics, response to SSA treatment, and histological granulation pattern.

  1. Subarachnoid hemosiderin deposition after subarachnoid hemorrhage on T2*-weighted MRI correlates with the location of disturbed cerebrospinal fluid flow on computed tomography cisternography.

    Science.gov (United States)

    Horita, Yoshifumi; Imaizumi, Toshio; Hashimoto, Yuji; Niwa, Jun

    2008-01-01

    A 72-year-old male was admitted with subarachnoid hemorrhage associated with a ruptured cerebral aneurysm. The aneurysm was treated with clipping soon after radiological examination. Eight weeks after the treatment, the patient suffered from secondary hydrocephalus resulting from blockage of the subarachnoid space due to subarachnoid granulation. Previous pathological examination revealed the granulation was associated with hemosiderin deposition. We investigated subarachnoid hemosiderin deposition in this patient using T2*-weighted (T2*-w) magnetic resonance image (MRI), a sensitive method for hemosiderin detection. computed tomography (CT) cisternography demonstrated that cerebrospinal fluid (CSF) flow was disturbed adjacent to sites of subarachnoid hemosiderin deposition on T2*-w MRI. Placement of a ventriculo-peritoneal shunt contributed to neurological improvement. In this case, T2*-w MRI was an effective means of diagnosing the location of disturbed CSF flow associated with subarachnoid hemosiderin deposition.

  2. Significance of periventricular hyperintensity in T2 weighted MRI on memory dysfunction and depression after stroke

    International Nuclear Information System (INIS)

    Bokura, Hirokazu; Kobayashi, Shotai; Yamaguchi, Shuhei; Yamashita, Kazuya; Koide, Hiromi

    1994-01-01

    We studied the effect of periventricular hyperintensity (PVH) in T2 weighted MRI on memory function and post-stroke depression in 159 patients with cerebrovacular disease. Memory function was assessed with Hasegawa's scale, and depressive state was estimated with Zung's self-rating depression scale. Patients showing diffusely distributed PVH had significantly low scores in memory function tests. Localized PVH around the anterior horns of the laterals ventricle was also associated with impaired memory function when the area of PVH was large. The incidence of post-stroke depression was high in patients with large PVH around the anterior horn in comparison with patients with PVH around the posterior horn. The severity of PVH around the posterior horn did not affect memory function and post-stroke depression. These findings suggest that memory dysfunction and post-stroke depression were accelerated by the diffusely or anteriorly distributed PVH. (author)

  3. Relationship between levels of serum creatinine and perirenal hyperintensity on heavily T2-weighted MR images

    Energy Technology Data Exchange (ETDEWEB)

    Erden, Ayse, E-mail: ayse.erden@medicine.ankara.edu.tr [Ankara University, School of Medicine, Department of Radiology, Talatpasa Bulvari, Sihhiye, 06100 Ankara (Turkey); Sahin, Burcu Savran, E-mail: bsavrans@hotmail.com [Ankara University, School of Medicine, Department of Radiology, Talatpasa Bulvari, Sihhiye, 06100 Ankara (Turkey); Orgodol, Horolsuren, E-mail: hoogii99@yahoo.com [Ankara University, School of Medicine, Department of Radiology, Talatpasa Bulvari, Sihhiye, 06100 Ankara (Turkey); Erden, Ilhan, E-mail: erden@medicine.ankara.edu.tr [Ankara University, School of Medicine, Department of Radiology, Talatpasa Bulvari, Sihhiye, 06100 Ankara (Turkey); Biyikli, Zeynep, E-mail: zeynep.biyikli@gmail.com [Ankara University, School of Medicine, Department of Biostatistics, Talatpasa Bulvari, Sihhiye, 06100 Ankara (Turkey)

    2011-11-15

    Objective: To determine the frequency of perirenal hyperintensity on heavily T2-weighted images and to evaluate its relationship with serum creatinine levels. Subjects and methods: Axial and coronal single-shot fast spin-echo images which have been originally obtained for MR cholangiopancreatography in 150 subjects were examined by two observers individually for the presence of perirenal hyperintensity. The morphologic properties of perirenal hyperintensity (peripheral rim-like, discontinuous, polar) were recorded. Chi square test was used to test whether the frequencies of bilateral perirenal hyperintensity differ significantly in subjects with high serum creatinine levels and those with normal creatinine levels. This test was also used to compare the frequencies of perirenal hyperintensity in patients with and without renal cysts and in patients with and without corticomedullary differentiation. A p value of less than 0.05 was considered to be statistically significant. Results: The perirenal hyperintensity was identified in 40 of 150 cases (26.6%) on heavily T2-weighted image. Serum creatinine levels were high in 18 of 150 cases (12%). The perirenal hyperintensity was present in 11 of 18 subjects (61%) with high serum creatinine levels and 26 of 132 subjects (19.7%) with normal creatinine levels. The difference of rates in two groups was statistically significant. Odds ratio was 6407 (95% confidence interval 2264-18,129). The frequency of perirenal hyperintensity was also significantly higher in subjects with renal cyst or cysts in whom serum creatinine levels were normal (p < 0.05) (37.5% vs. 11.8%). Conclusion: Perirenal hyperintensities are more frequent in patients with high serum creatinine levels. They are also more common in patients with simple renal cysts.

  4. Relationship between levels of serum creatinine and perirenal hyperintensity on heavily T2-weighted MR images

    International Nuclear Information System (INIS)

    Erden, Ayse; Sahin, Burcu Savran; Orgodol, Horolsuren; Erden, Ilhan; Biyikli, Zeynep

    2011-01-01

    Objective: To determine the frequency of perirenal hyperintensity on heavily T2-weighted images and to evaluate its relationship with serum creatinine levels. Subjects and methods: Axial and coronal single-shot fast spin-echo images which have been originally obtained for MR cholangiopancreatography in 150 subjects were examined by two observers individually for the presence of perirenal hyperintensity. The morphologic properties of perirenal hyperintensity (peripheral rim-like, discontinuous, polar) were recorded. Chi square test was used to test whether the frequencies of bilateral perirenal hyperintensity differ significantly in subjects with high serum creatinine levels and those with normal creatinine levels. This test was also used to compare the frequencies of perirenal hyperintensity in patients with and without renal cysts and in patients with and without corticomedullary differentiation. A p value of less than 0.05 was considered to be statistically significant. Results: The perirenal hyperintensity was identified in 40 of 150 cases (26.6%) on heavily T2-weighted image. Serum creatinine levels were high in 18 of 150 cases (12%). The perirenal hyperintensity was present in 11 of 18 subjects (61%) with high serum creatinine levels and 26 of 132 subjects (19.7%) with normal creatinine levels. The difference of rates in two groups was statistically significant. Odds ratio was 6407 (95% confidence interval 2264-18,129). The frequency of perirenal hyperintensity was also significantly higher in subjects with renal cyst or cysts in whom serum creatinine levels were normal (p < 0.05) (37.5% vs. 11.8%). Conclusion: Perirenal hyperintensities are more frequent in patients with high serum creatinine levels. They are also more common in patients with simple renal cysts.

  5. MR imaging of advanced gastric cancer: comparison between T1-weighted FLASH, T2-weighted TSE, and TrueFISP

    International Nuclear Information System (INIS)

    Seong, Chang Kyu; Kim, Ah Young; Kim, Tae Kyoung; Han, Joon Koo; Choi, Byung Ihn; Song, Chi Sung

    1998-01-01

    To compare the usefulness of three MR sequences for the depiction and staging of advanced gastric cancer (AGC). MR imaging was performed in 20 patients in whom AGC was proven by endoscopy. Axial scans with T1-weighted fast low-angle shot (FLASH), T2-weighted turbo spin-echo (TSE), and true fast imaging with steady state precession (TrueFISP) MR sequences were obtained. We measured the signal-to-noise ratio (S/N) of gastric cancer and signal difference-to-noise ratio (SD/N) between cancer and intraluminal fluid, cancer and the pancreas, and cancer and perigastric fat in each MR sequence. We also graded lesion conspicuity (poor, fair, or good), and the degree of serosal invasion in each sequence. All results were correlated with histopathologic findings. TrueFISP was superior to FLASH or TSE in lesion conspicuity, and showed the highest value of SD/N between cancer and intraluminal fluid. FLASH showed the highest value of SD/N between cancer and the pancreas, and cancer and perigastric fat. The accuracy of T-staging of AGC with MRI was 75% using FLASH, 70% using TrueFISP, and 60% using TSE. FLASH sequence understaged in three cases(15%) and overstaged in two (10%). In Using the TrueFISP sequence, six cases(30%) were overstaged. TrueFISP showed the best lesion conspicuity, but tended to overstage the lesion. T1-weighted FLASH sequence showed the highest value of SD/N on the extraluminal side of the gastric wall, and was better than T2-weighted TSE or TrueFISP for T-staging of AGC

  6. Improved focal liver lesion detection: comparison of single-shot diffusion-weighted echoplanar and single-shot T-2 weighted turbo spin echo techniques

    NARCIS (Netherlands)

    Coenegrachts, K.; Delanote, J.; ter Beek, L.; Haspeslagh, M.; Bipat, S.; Stoker, J.; van Kerkhove, F.; Steyaert, L.; Rigauts, H.; Casselman, J. W.

    2007-01-01

    The purpose of this study was to compare diffusion-weighted respiratory-triggered single-shot spin echo echoplanar imaging (SS SE-EPI) sequence using four b-values (b=0, b=20, b=300, b=800 s mm(-2)) and single-shot T-2 weighted turbo spin echo (T2W SS TSE) in patients with focal liver lesions, with

  7. T2 relaxation time analysis in patients with multiple sclerosis: correlation with magnetization transfer ratio

    International Nuclear Information System (INIS)

    Papanikolaou, Nickolas; Papadaki, Eufrosini; Karampekios, Spyros; Maris, Thomas; Prassopoulos, Panos; Gourtsoyiannis, Nicholas; Spilioti, Martha

    2004-01-01

    The aim of the current study was to perform T2 relaxation time measurements in multiple sclerosis (MS) patients and correlate them with magnetization transfer ratio (MTR) measurements, in order to investigate in more detail the various histopathological changes that occur in lesions and normal-appearing white matter (NAWM). A total number of 291 measurements of MTR and T2 relaxation times were performed in 13 MS patients and 10 age-matched healthy volunteers. Measurements concerned MS plaques (105), NAWM (80), and ''dirty'' white matter (DWM; 30), evenly divided between the MS patients, and normal white matter (NWM; 76) in the healthy volunteers. Biexponential T2 relaxation-time analysis was performed, and also possible linearity between MTR and mean T2 relaxation times was evaluated using linear regression analysis in all subgroups. Biexponential relaxation was more pronounced in ''black-hole'' lesions (16.6%) and homogeneous enhancing plaques (10%), whereas DWM, NAWM, and mildly hypointense lesions presented biexponential behavior with a lower frequency(6.6, 5, and 3.1%, respectively). Non-enhancing isointense lesions and normal white matter did not reveal any biexponentional behavior. Linear regression analysis between monoexponential T2 relaxation time and MTR measurements demonstrated excellent correlation for DWM(r=-0.78, p<0.0001), very good correlation for black-hole lesions(r=-0.71, p=0.002), good correlation for isointense lesions(r=-0.60, p=0.005), moderate correlation for mildly hypointense lesions(r=-0.34, p=0.007), and non-significant correlation for homogeneous enhancing plaques, NAWM, and NWM. Biexponential T2 relaxation-time behavior is seen in only very few lesions (mainly on plaques with high degree of demyelination and axonal loss). A strong correlation between MTR and monoexponential T2 values was found in regions where either inflammation or demyelination predominates; however, when both pathological conditions coexist, this linear

  8. Non-invasive detection of biliary leaks using Gd-EOB-DTPA-enhanced MR cholangiography: comparison with T2-weighted MR cholangiography

    International Nuclear Information System (INIS)

    Kantarci, Mecit; Pirimoglu, Berhan; Bayraktutan, Ummugulsum; Ogul, Hayri; Kizrak, Yesim; Eren, Suat; Karabulut, Nevzat; Ozturk, Gurkan; Aydinli, Bulent; Yilmaz, Sinan

    2013-01-01

    To evaluate the added role of T1-weighted (T1w) gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance cholangiography (MRC) compared with T2-weighted MRC (T2w-MRC) in the detection of biliary leaks. Ninety-nine patients with suspected biliary complications underwent routine T2w-MRC and T1w contrast-enhanced (CE) MRC using Gd-EOB-DTPA to identify biliary leaks. Two observers reviewed the image sets separately and together. MRC findings were compared with those of surgery and percutaneous transhepatic cholangiopancreatography. The sensitivity, specificity and accuracy of the techniques in identifying biliary leaks were calculated. Accuracy of locating biliary leaks was superior with the combination of Gd-EOB-DTPA-enhanced MRC and T2w-MRC (P < 0.05).The mean sensitivities were 79 % vs 59 %, and the mean accuracy rates were 84 % vs 58 % for combined CE-MRC and T2w-MRC vs sole T2w-MRC. Nineteen out of 21 patients with biliary-cyst communication, 90.4 %, and 12/15 patients with post-traumatic biliary extravasations, 80 %, were detected by the combination of Gd-EOB-DTPA-enhanced MRC and T2w-MRC images, P < 0.05. Gd-EOB-DTPA-enhanced MRC yields information that complements T2w-MRC findings and improves the identification and localisation of the bile extravasations (84 % accuracy, 100 % specificity, P < 0.05). We recommend Gd-EOB-DTPA-enhanced MRC in addition to T2w-MRC to increase the preoperative accuracy of identifying and locating extravasations of bile. (orig.)

  9. The effects of particle shape and size on T2 relaxation in magnetic resonance imaging.

    Science.gov (United States)

    York, Joseph N; Albanese, Christopher; Rodriguez, Olga; Le, Yi-Chien; Ackun-Farmmer, Marian; Van Keuren, Edward

    2014-11-01

    Superparamagnetic iron oxide nanoparticles have recently been developed as T2 contrast agents for magnetic resonance imaging. Here we report the dependence of the phase relaxivity, r2, on the particle shape. We show that the size dependence of the relaxivity for spherical particles can be generalized to spheroidal particles. In addition, we show that the saturation of relaxivity above a certain size observed in spherical particles does not occur in the spheroidal particles investigated.

  10. 7T MRI-Histologic Correlation Study of Low Specific Absorption Rate T2-Weighted GRASE Sequences in the Detection of White Matter Involvement in Multiple Sclerosis.

    Science.gov (United States)

    Bagnato, Francesca; Hametner, Simon; Pennell, David; Dortch, Richard; Dula, Adrienne N; Pawate, Siddharama; Smith, Seth A; Lassmann, Hans; Gore, John C; Welch, Edward B

    2015-01-01

    The high value of the specific absorption rate (SAR) of radio-frequency (RF) energy arising from the series of RF refocusing pulses in T2-weighted (T2-w) turbo spin echo (TSE) MRI hampers its clinical application at 7.0 Tesla (7T). T2-w gradient and spin echo (GRASE) uses the speed from gradient refocusing in combination with the chemical-shift/static magnetic field (B0) inhomogeneity insensitivity from spin-echo refocusing to acquire T2-w images with a limited number of refocusing RF pulses, thus reducing SAR. To investigate whether low SAR T2-w GRASE could replace T2-w TSE in detecting white matter (WM) disease in MS patients imaged at 7T. The .7 mm3 isotropic T2-w TSE and T2-w GRASE images with variable echo times (TEs) and echo planar imaging (EPI) factors were obtained on a 7T scanner from postmortem samples of MS brains. These samples were derived from brains of 3 female MS patients. WM lesions (WM-Ls) and normal-appearing WM (NAWM) signal intensity, WM-Ls/NAWM contrast-to-noise ratio (CNR) and MRI/myelin staining sections comparisons were obtained. GRASE sequences with EPI factor/TE = 3/50 and 3/75 ms were comparable to the SE technique for measures of CNR in WM-Ls and NAWM and for detection of WM-Ls. In all sequences, however, identification of areas with remyelination, Wallerian degeneration, and gray matter demyelination, as depicted by myelin staining, was not possible. T2-w GRASE images may replace T2-w TSE for clinical use. However, even at 7T, both sequences fail in detecting and characterizing MS disease beyond visible WM-Ls. Copyright © 2015 by the American Society of Neuroimaging.

  11. 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

  12. High-SNR multiple T2(*)-contrast magnetic resonance imaging using a robust denoising method based on tissue characteristics.

    Science.gov (United States)

    Eo, Taejoon; Kim, Taeseong; Jun, Yohan; Lee, Hongpyo; Ahn, Sung Soo; Kim, Dong-Hyun; Hwang, Dosik

    2017-06-01

    To develop an effective method that can suppress noise in successive multiecho T 2 (*)-weighted magnetic resonance (MR) brain images while preventing filtering artifacts. For the simulation experiments, we used multiple T 2 -weighted images of an anatomical brain phantom. For in vivo experiments, successive multiecho MR brain images were acquired from five healthy subjects using a multiecho gradient-recalled-echo (MGRE) sequence with a 3T MRI system. Our denoising method is a nonlinear filter whose filtering weights are determined by tissue characteristics among pixels. The similarity of the tissue characteristics is measured based on the l 2 -difference between two temporal decay signals. Both numerical and subjective evaluations were performed in order to compare the effectiveness of our denoising method with those of conventional filters, including Gaussian low-pass filter (LPF), anisotropic diffusion filter (ADF), and bilateral filter. Root-mean-square error (RMSE), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were used in the numerical evaluation. Five observers, including one radiologist, assessed the image quality and rated subjective scores in the subjective evaluation. Our denoising method significantly improves RMSE, SNR, and CNR of numerical phantom images, and CNR of in vivo brain images in comparison with conventional filters (P structure conspicuity (8.2 to 9.4 out of 10) and naturalness (9.2 to 9.8 out of 10) among the conventional filters in the subjective evaluation. This study demonstrates that high-SNR multiple T 2 (*)-contrast MR images can be obtained using our denoising method based on tissue characteristics without noticeable artifacts. Evidence level: 2 J. MAGN. RESON. IMAGING 2017;45:1835-1845. © 2016 International Society for Magnetic Resonance in Medicine.

  13. 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

  14. Combining T2-weighted with dynamic MR images for computerized classification of prostate lesions

    Science.gov (United States)

    Vos, Pieter C.; Hambrock, Thomas; Barentsz, Jelle O.; Huisman, Henkjan J.

    2008-03-01

    In this study, we investigate the diagnostic performance of our CAD system when discriminating prostate cancer from benign lesions and normal peripheral zone using registered multi-modal images. We have developed a method that automatically extracts quantitative T2 values out of acquired T2-w images and evaluated its additional value to the discriminating performance of our CAD system. This study addresses 2 issues when using both T2-w and dynamic MR images for the characterization of prostate lesions. Firstly, T2-w images do not provide quantitative values, and secondly, images can be misaligned due to patient movements. To compensate, a mutual information registration strategy is performed after which T2 values are estimated using the acquired proton density images. From the resulted quantitative T2 maps as well as the dynamic images relevant features were extracted for training a support vector machine as classfier. The output of the classifier was used as a measure of likelihood of malignancy. General performance of the scheme was evaluated using the area under the ROC curve. We conclude that it is feasible to automatically extract diagnostic T2 values out of acquired T2-w images. Furthermore, a discriminating performance of 0.75 (0.66-0.85) was obtained when only using T2-values as feature. Combining the T2 values with pharmacokinetic parameters did not increase diagnostic performance in a pilot study.

  15. MR imaging with fluid attenuated inversion recovery sequence of childhood adrenoleukodystrophy : comparison with T2 weighted spin echo imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Asiry; Seo, Jeong-Jin; Jeong, Gwang Woo; Chung, Tae Woong; Jeong, Yong Yeon; Kang, Heoung Keun; Kook, Hoon; Woo, Young Jong; Hwang, Tai Joo [Chonnam Univ. Medical School, Seoul (Korea, Republic of)

    1999-03-01

    The purpose of this study was to evaluate the usefulness of FLAIR(Fluid Attenuated Inversion Recovery) MR imaging in childhood adrenoleukodystrophy by comparing with those of T2-weighted FSE imaging, and to correlate MRI findings with clinical manifestations. Axial FLAIR images(TR/TE/TI=10004/123/2200) and T2-weighted FSE images(TR/TE=4000/104) of brain in six male patients(age range : 6-17 years, mean age : 10.2 years) with biochemically confirmed adrenoleukodystrophy were compared visually by two radiologists for detection, conspicuity, and the extent of lesion. Quantitatively, we compared lesion/CSF contrast, lesion/CSF contrast to noise ratio(CNR), lesion/white matter(WM) contrast, and lesion/WM CNR between FLAIR and T2 weighted image. We correlated MR findings with clinical manifestations of neurologic symptoms and evaluated whether MRI could detect white matter lesions in neurologically asymptomatic patients. Visual detection of lesions was better with FLAIR images in 2 of the 6 cases and it was equal in the remainders. Visual conspicuity and detection of the extent of lesion were superior on FLAIR images than T2-weighted images in all 6 cases. In the quantitative assessment of lesions, FLAIR was superior to T2-weighted image for lesion/CSF contrast and lesion/CSF CNR, but was inferior to T2 weighted image for lesion/WM contrast and lesion/WM CNR. In one case, FLAIR images distinguished the portion of encephalomalacic change from lesions. MR findings of adrenoleukodystrophy were correlated with clinical manifestations in symptomatic 4 cases, and also detected white matter lesions in asymptomatic 2 cases. MR imaging with FLAIR sequence provided images that were equal or superior to T2-weighted images in the evaluation of childhood adrenoleukodystrophy. MRI findings were well correlated with clinical manifestations and could detect white matter lesions in neurologically asymptomatic adrenoleukodystrophy patients.

  16. 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

  17. 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.

  18. 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.)

  19. 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.

  20. Dot-like hemosiderin deposition on T2*-weighted MR imaging associated with nonhypertensive intracerebral hemorrhage.

    Science.gov (United States)

    Imaizumi, Toshio; Horita, Yoshifumi; Chiba, Masahiko; Miyata, Kei; Toyama, Kentaro; Yoshifuji, Kazuhisa; Hashimoto, Yuji; Niwa, Jun

    2006-01-01

    Microangiopathy, a disorder often related to hypertension, is an important cause of deep intracerebral hematoma (ICH). The microangiopathy is associated with dot-like low-intensity spots (a dot-like hemosiderin spot: dotHS) on gradient-echo T2*-weighted MR images that have been histologically diagnosed as old microbleeds. The locations of dotHS are consistent with deep ICH. To investigate how dotHS or other risk factors contribute to nonhypertensive deep ICH, the number and location of dotHSs, as well as other risk factors were examined in 213 deep ICH patients (106 males, 107 females, age: 37-94 (65.8 +/- 11.2) years) consecutively admitted to Hakodate Municipal Hospital. Patients were divided into two subgroups according to the presence or absence of hypertension. DotHSs were also divided into deep and subcortical dotHS and investigated independently. Odds ratios (ORs) were estimated from logistic regression analyses. Furthermore, nonhypertensive ICH patients were compared with nonhypertensive healthy volunteers matched for age and sex. No risk factors were identified in the 31 nonhypertensive deep ICH patients that differed from those found in the 182 hypertensive deep ICH patients. Deep dotHS > or = 1 (OR: 25.5; 95% CI: 4.76-137; P = .0002), subcortical dotHS > or = 1 (OR: 9.0; 95% CI: 1.79-44.9; P = .046), diabetes mellitus (OR: 9.0; 95% CI: 1.53-52.3; P = .015), and smoking (OR, 9.6; 95% CI; 1.8-49.8, P = .007) significantly elevated the risk of nonhypertensive ICH, compared to the healthy volunteers. Our findings suggest that deep and subcortical dotHSs may be risk factors for the development of non-hypertensive deep ICH.

  1. MRI of acute post-ischemic cerebral hemorrhage in stroke patients: diagnosis with T2*-weighted gradient-echo sequences

    International Nuclear Information System (INIS)

    Hermier, M.; Nighoghossian, N.; Derex, L.; Blanc-Lasserre, K.; Trouillas, P.; Berthezene, Y.; Froment, J.C.

    2001-01-01

    The use of T2 * -weighted sequences has been advocated for early differentiation between hematoma and ischemia in patients with acute stroke. Early hemorrhagic transformation of ischemic stroke is an adverse event which may occur under treatment and may impair the prognosis: our aim is to evaluate the ability of T2*-weighted gradient-echo sequence (T2 * GRE) to detect post-ischemic cerebral hemorrhage. The imaging procedure included: (1) baseline CT scan at admission. (2) MRI performed within 24 h of therapy onset including: (a) dual fast spin echo T2 sequence, (b) axial isotropic echoplanar diffusion-weighted imaging sequence, (c) conventional T2* GRE, and (d) 3D TOF turbo MRA. Post-ischemic cerebral hemorrhage was diagnosed if T2 * GRE detected a focal intraparenchymal area of signal loss. The diameter of this lesion had to be more than 5 mm in order to eliminate past microbleeds. (3) Patients who showed an early suspicion of bleeding on MRI promptly had a second CT scan, and, if this one was negative for bleeding, another CT scan was performed 1 day later. All the other patients had a control CT scan during the first week. Forty-five consecutive patients have been included. T2* GRE showed intracranial bleeding in seven. The diagnosis of post-ischemic cerebral bleeding was confirmed by CT in all patients. Control CT scans did not reveal any post-ischemic cerebral hemorrhage in patients with negative MRI. In one case, hemorrhage was seen earlier on MRI than on CT scan. In conclusion, T2 * GRE appeared to be at least as efficient as CT scan in the detection of early post-ischemic cerebral hemorrhage. (orig.)

  2. 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.

  3. Three-dimensional isotropic T2-weighted fast spin-echo (VISTA) ankle MRI versus two-dimensional fast spin-echo T2-weighted sequences for the evaluation of anterior talofibular ligament injury.

    Science.gov (United States)

    Park, H J; Lee, S Y; Park, N H; Rho, M H; Chung, E C; Park, J H; Park, S J

    2016-04-01

    To compare the performance of axial images of the ankle joint on three-dimensional (3D) volume isotropic turbo spin echo acquisition (VISTA) with that of two-dimensional (2D) fast spin echo (FSE) T2-weighted images for the diagnosis of anterior talofibular ligament (ATFL) injury. This retrospective study included 101 patients who underwent both 2D FSE T2-weighted and 3D VISTA magnetic resonance imaging (MRI) of the ankle. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of both sequences were measured. The anatomical identification score and diagnostic performances of both sequences were evaluated by two radiologists. The diagnostic performances of 3D VISTA and 2D FSE images were analysed in terms of sensitivity, specificity, and accuracy for diagnosing ATFL injury. Surgically or clinically confirmed diagnoses were used as reference standards. The margin sharpness scores on 3D VISTA were significantly inferior to those of 2D FSE (p<0.001). Other scores (entire length, entire width) were not significantly different between the two imaging methods. The SNRs and CNRs of 3D VISTA were significantly higher than those of 2D FSE (p<0.001). When diagnoses were classified as normal and abnormal, the specificity of the 3D VISTA images for the diagnosis of ATFL injury was 95.7%, significantly superior to 2D FSE (84.3-85.7%). There were no significant differences between 3D VISTA and 2D FSE images in sensitivity or accuracy for diagnosis (p=0.227-1.000), with the exception of accuracy by reader 1 (p=0.039). 3D VISTA imaging has a diagnostic performance comparable to that of 2D FSE for the diagnosis of ATFL injury, although 3D VISTA is inferior to 2D FSE for the evaluation of margin sharpness. Replacing axial and coronal images with 3D VISTA can save imaging time without negatively impacting the diagnostic ability for ATFL injury. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  4. “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.

  5. 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.)

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

    Science.gov (United States)

    Ganzetti, Marco; Wenderoth, Nicole; Mantini, Dante

    2015-09-01

    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.

  7. 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.)

  8. 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.)

  9. 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

  10. 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

    : Intertwin placental T2* difference is strongly related to intertwin birthweight difference, even when performed several weeks before birth. Placental T2* might be a future method to predict intertwin birthweight difference in dichorionic twin pregnancies. Further studies should be performed in order......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......, Aalborg University Hospital, Aalborg , Denmark. 5. Department of Obstetrics and Gynecology, Aarhus University Hospital Skejby, Aarhus, Denmark. 6. Department of Pathology, Aalborg University Hospital, Aalborg, Denmark. ABSTRACT BODY: Objectives: Intertwin birth weight discordance is associated...

  11. 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

  12. 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

  13. 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

  14. 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.

  15. Cardiac MRI. T2-mapping versus T2-weighted dark-blood TSE imaging for myocardial edema visualization in acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Nassenstein, K.; Nensa, F.; Schlosser, T.; Umutlu, L.; Lauenstein, T. [University Hospital Essen (Germany). Dept. of Diagnostic and Interventional Radiology and Neuroradiology; Bruder, O. [Elisabeth Hospital, Essen (Germany). Dept. of Cardiology and Angiology; Maderwald, S.; Ladd, M.E. [Duisburg-Essen Univ., Essen (Germany). Erwin L. Hahn Institute for Magnetic Resonance Imaging

    2014-02-15

    Purpose: To assess the diagnostic accuracy of T2 mapping for the detection of myocardial edema in acute myocardial infarction (AMI), and to compare this diagnostic accuracy with that of the current standard for myocardial edema imaging, which is T2w dark-blood TSE imaging. Materials and Methods: 29 patients with AMI were examined at 1.5 T. For the visualization of myocardial edema, T2 maps, calculated from three T2w SSFP images, and T2w dark-blood TSE images were acquired in standard short- and long-axis views. Cine SSFP images were acquired for the analysis of left ventricular (LV) function and late gadolinium enhancement images (LGE) for the visualization of myocardial necrosis. The T2 maps as well as the T2w dark-blood TSE images were evaluated twice independently from the cine SSFP and LGE images. The presence or absence of myocardial edema was rated visually for each LV segment. As the standard of reference, the infarct zone was defined based on the cine SSFP and the LGE images. Results: In this segment-based analysis, T2 mapping showed a sensitivity of 82 % and a specificity of 94 % for the detection of edema in the infarct zone. T2w dark-blood TSE imaging revealed a sensitivity of 50 % and a specificity of 98 %. T2 mapping showed a higher intra-rater agreement compared to T2w dark-blood TSE imaging ({kappa}: 0.87 vs. 0.76). Conclusions: T2 mapping allows for the visualization of myocardial edema in AMI with a high sensitivity and specificity, and features better diagnostic accuracy in terms of a higher sensitivity compared to T2w dark-blood TSE imaging. (orig.)

  16. Diagnosis of spinal dural arteriovenous fistula using 3D T2-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kralik, Stephen F.; Murph, Daniel; Mehta, Peter; O' Neill, Darren P. [Indiana University School of Medicine, Department of Radiology and Imaging Sciences, Indianapolis, IN (United States)

    2017-10-15

    To evaluate spinal MRIs without and with 3D T2W imaging among patients without and with spinal dural arteriovenous fistula (SDAVF) confirmed by spinal digital subtraction angiography (DSA). A retrospective case-control study was performed among patients without and with SDAVF who had both spinal MRIs and gold standard spinal DSA. Two neuroradiologists independently reviewed spinal MRIs that were performed with either sagittal T2W turbo spin echo (2D group) or sagittal 3D T2W sampling perfection with application-optimized contrasts using different flip-angle evolutions (SPACE) (3D group) and documented the presence or absence of SDAVF. Using spinal DSA diagnosis as a gold standard, the sensitivity, specificity, and interobserver agreement for the 2D-group and 3D-group MRI diagnosis were calculated. The 2D group consisted of 21 patients and the 3D group consisted of 16 patients. For both radiologists, the 2D group demonstrated a sensitivity of 100% and specificity of 100%. Interobserver agreement in the 2D group was perfect (k = 1.0). For both radiologists, the 3D group demonstrated sensitivity of 100.0% and specificity of 92.3%. Interobserver agreement in the 3D group was perfect (k = 1.0). While flow voids were considered more conspicuous, spinal cord signal abnormality was considered less conspicuous with 3D T2W SPACE compared with conventional 2D STIR sequence. 3D T2W SPACE should be used in conjunction with 2D T2W sequences to more accurately detect abnormal cord signal and determine when perimedullary flow voids are pathologically abnormal for the radiologic diagnosis of SDAVF. (orig.)

  17. [Distinction between adrenal adenomas and metastases using 0.5 Telsa MR imaging: diagnosis with out-of-phase T2*-weighted gradient-field-echo image].

    Science.gov (United States)

    Ichikawa, T; Fujimoto, H; Uchiyama, G; Murakami, K; Ohtomo, K

    1994-03-25

    The purpose of this study was to investigate the ability of MR imaging with a 0.5-T apparatus to distinguish adrenal adenomas from adrenal metastases. The series included 23 adrenal adenomas (18 non-hyperfunctioning adenomas, 5 hyperfunctioning) and 23 adrenal metastases (14 from lung, 5 liver, 3 colon, and 1 stomach cancer). The signal intensity (SI) ratio (adrenal tumor/liver) on T1-, T2-, and T2*-weighted MR images was calculated for adrenal tissue characterization. Adrenal adenomas were more precisely distinguished from adrenal metastases on T2*-weighted images (21/23, 91%) than on T2-weighted images (15/23, 65%). In conclusion, T2*-weighted images were better than routine T2-weighted images in distinguishing adrenal adenomas from adrenal metastases. The reason could be that the total signal intensity of adrenal adenomas which contained some fat components decreased on T2*-weighted images due to an out-of-phase effect.

  18. 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.

  19. Role of EPI in diagnosing cavernous hemangioma and small HCC : comparison with fast T2-weighted MR Imaging

    International Nuclear Information System (INIS)

    Kim, Suk; Lee, Jun Woo; Kim, Chang Won; Jung, Hyun Woo; Choi, Sang Yoel; Lee, Suck Hong; Kim, Byung Soo

    1998-01-01

    The purpose of this study is to compare single-shot echo-planar MR imaging (EPI) with breath-hold fast T2-weighted imaging (HASTE or Turbo spin-echo T2WI) for evaluation of the role of EPI in distinguishing small hepatocellular carcinoma from cavernous hemangioma. We retrospectively evaluated MR images of 35 patients (21 cases of small HCC and 14 cases of cavernous hemangioma). EPI and breath-hold fast T2WI images were obtained and compared on the basis of lesion detection sensitivity, lesion-to-liver signal intensity ratio (SIR), contrast ratio (CR), and lesion-to-liver contrast to noise ratio (CNR). For the detection of small HCC, the sensitivity of EPI and breath-hold fast T2WI were equal in 14 of 21 cases (71.4%). The detection sensitivity of cavernous hemangioma with EPI and breath-hold fast T2WI was 100 % (14/14). Mean SIR on breath-hold fast T2WI was 2.02 ± 0.45 for small HCC and 3.65 ± 0.97 for cavernous hemangioma; on EPI, the corresponding figures were 2.91 ± 0.57 for cavernous hemangioma; On EPI, the figures obtained were 2.27 ± 0.52 and 6.26 ± 2.19, respectively. Mean CNR on breath-hold fast T2WI was 14.24 ± 4.098 for small HCC and 50.28 ± 10.96 for cavernous hemangioma, while on EPI, the corresponding figures were 13.84 ± 3.02 and 45.44 ± 11.21. In detecting focal hepatic mass, the sensitivity of EPI and breath-hold fast T2WI are comparable for the diagnosis of small HCC and cavernous hemangioma, EPI can provided additional information. (author). 20 refs., 2 tabs., 4 figs

  20. Breast cancer detection using double reading of unenhanced MRI including T1-weighted, T2-weighted STIR, and diffusion-weighted imaging: a proof of concept study.

    Science.gov (United States)

    Trimboli, Rubina M; Verardi, Nicola; Cartia, Francesco; Carbonaro, Luca A; Sardanelli, Francesco

    2014-09-01

    The purpose of this study was to investigate the diagnostic performance of unenhanced MRI in detecting breast cancer and to assess the impact of double reading. A total of 116 breasts of 67 women who were 36-89 years old were studied at 1.5 T using an unenhanced protocol including axial T1-weighted gradient-echo, T2-weighted STIR, and echo-planar diffusion-weighted imaging (DWI). Two blinded readers (R1 and R2) independently evaluated unenhanced images using the BIRADS scale. A combination of pathology and negative follow-up served as the reference standard. McNemar and kappa statistics were used. Per-breast cancer prevalence was 37 of 116 (32%): 30 of 37 (81%) invasive ductal carcinoma, five of 37 (13%) ductal carcinoma in situ, and two of 37 (6%) invasive lobular carcinoma. Per-breast sensitivity of unenhanced MRI was 29 of 37 (78%) for R1, 28 of 37 (76%) for R2, and 29 of 37 (78%) for double reading. Specificity was 71 of 79 (90%) for both R1 and R2 and 69 of 79 (87%) for double reading. Double reading did not provide a significant increase in sensitivity. Interobserver agreement was almost perfect (Cohen κ = 0.873). An unenhanced breast MRI protocol composed of T1-weighted gradient echo, T2-weighted STIR, and echo-planar DWI enabled breast cancer detection with sensitivity of 76-78% and specificity of 90% without a gain in sensitivity from double reading.

  1. 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

  2. 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

  3. High-resolution T2-weighted cervical cancer imaging : a feasibility study on ultra-high-field 7.0-T MRI with an endorectal monopole antenna

    OpenAIRE

    Hoogendam, Jaap; van Kalleveen, Irene; Arteaga de Castro, Catalina; Raaijmakers, AJE; Verheijen, René H M; van Den Bosch, Maurice A A J; Klomp, DWJ; Zweemer, RP; Veldhuis, Wouter B.

    2017-01-01

    Objectives We studied the feasibility of high-resolution T2-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. Methods 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 ...

  4. 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.)

  5. Predictive value of T2-weighted imaging and contrast-enhanced MR imaging in assessing myometrial invasion in endometrial cancer: a pooled analysis of prospective studies

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Lian-Ming [Shanghai Jiao Tong University School of Medicine, Department of Radiology, Renji Hospital, Shanghai (China); Wayne State University, Department of Radiology, Detroit, MI (United States); Xu, Jian-Rong; Gu, Hai-Yan; Hua, Jia [Shanghai Jiao Tong University School of Medicine, Department of Radiology, Renji Hospital, Shanghai (China); Haacke, E.M.; Hu, Jiani [Wayne State University, Department of Radiology, Detroit, MI (United States)

    2013-02-15

    To obtain diagnostic performance values of T2-weighted imaging (T2WI) and contrast-enhanced magnetic resonance imaging (CE-MRI) in the prediction of myometrial invasion in patients with endometrial cancer. Databases including MEDLINE and EMBASE were searched for relevant original articles published from January1995 to March 2012. Pooled estimation data were obtained by statistical analysis. Eleven articles (548 patients) were included. For assessing any myometrial involvement, the pooled sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for CE-MRI were 0.81 (95% CI, 0.72, 0.88), 0.72 (95% CI, 0.64, 0.79), 0.65 (95% CI, 0.56, 0.73) and 0.85 (95% CI, 0.78, 0.91); for T2WI, they were 0.87 (95% CI, 0.78, 0.94), 0.58 (95% CI, 0.47, 0.69), 0.64 (95% CI, 0.54, 0.73), 0.84 (95% CI, 0.73, 0.92) respectively. The pooled specificity of CE-MRI (0.72) was significantly higher than T2WI (0.58) (P < 0.05). For assessing deep myometrial involvement, there was no statistically significant difference between CE-MRI and T2WI, (P > 0.05). CE-MRI has a good diagnostic performance in the prediction of any myometrial invasion and is superior to T2WI. But its PPV is somewhat suboptimal. For assessing deep myometrial involvement, its NPV appears relative high and negative findings strongly suggest an absence of deep myometrial involvement, which can guide therapeutic decision-making. (orig.)

  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. 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.

  9. Dynamic ASL and T2-weighted MRI in exercising calf muscle at 7 T: a feasibility study.

    Science.gov (United States)

    Schewzow, Kiril; Fiedler, Georg Bernd; Meyerspeer, Martin; Goluch, Sigrun; Laistler, Elmar; Wolzt, Michael; Moser, Ewald; Schmid, Albrecht Ingo

    2015-03-01

    The aim of this study was to develop a measurement protocol for noninvasive simultaneous perfusion quantification and T2 *-weighted MRI acquisition in the exercising calf muscle at 7 Tesla. Using a nonmagnetic ergometer and a dedicated in-house built calf coil array, dynamic pulsed arterial spin labeling (PASL) measurements with a temporal resolution of 12 s were performed before, during, and after plantar flexion exercise in 16 healthy volunteers. Postexercise peak perfusion in gastrocnemius muscle (GAS) was 27 ± 16 ml/100g/min, whereas in soleus (SOL) and tibialis anterior (TA) muscles it remained at baseline levels. T2 *-weighted and ASL time courses in GAS showed comparable times to peak of 161 ± 72 s and 167 ± 115 s, respectively. The T2 *-weighted signal in the GAS showed a minimum during exercise (88 ± 6 % of the baseline signal) and a peak during the recovery (122 ± 9%), whereas in all other muscles only a signal decrease was observed (minimum 91 ± 6% in SOL; 87 ± 8% in TA). We demonstrate the feasibility of dynamic perfusion quantification in skeletal muscle at 7 Tesla using PASL. This may help to better investigate the physiological processes in the skeletal muscle and also in diseases such as diabetes mellitus and peripheral arterial disease. © 2014 Wiley Periodicals, Inc.

  10. Fast spin-echo T2-weighted MR imaging of tongue cancer; the value of fat-suppression

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Zu Byoung; Na, Dong Gyu; Ryoo, Jae Wook; Kim, Kyeong Ah; Byun, Hong Sik; Baek, Chung Whan; Son, Yong Ik [Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)

    2000-12-01

    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.

  11. 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.)

  12. 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.

  13. Repeatability of magnetic resonance fingerprinting T1and T2estimates 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.

  14. Adhesive capsulitis of the shoulder: value of inferior glenohumeral ligament signal changes on T2-weighted fat-saturated images.

    Science.gov (United States)

    Gondim Teixeira, Pedro A; Balaj, Clémence; Chanson, Anne; Lecocq, Sophie; Louis, Matthias; Blum, Alain

    2012-06-01

    The objective of our study was to evaluate the performance of MRI for the diagnosis of adhesive capsulitis using signal intensity changes of the inferior glenohumeral ligament on T2-weighted fat-saturated sequences. MR images of 34 shoulders with a final clinical diagnosis of adhesive capsulitis were compared with those of an age-matched control group (34 shoulders) with no clinical signs of adhesive capsulitis. MR images were acquired before and after IV injection of gadolinium and were evaluated by two readers. The T2 signal intensity at the inferior glenohumeral ligament, the thickness of the coracohumeral ligament, and whether there was obliteration of subcoracoid fat were evaluated on unenhanced images. Enhancement at the inferior glenohumeral ligament and enhancement at the rotator interval were evaluated on contrast-enhanced images. The sensitivity, specificity, and interobserver variability of these signs were calculated. T2 hyperintensity of the inferior glenohumeral ligament showed a high sensitivity (85.3-88.2%) and high specificity (88.2%) for the diagnosis of adhesive capsulitis with excellent interobserver variability (κ = 0.85). Signal analysis at the inferior glenohumeral ligament presented a higher sensitivity and a better interobserver agreement than the other signs of adhesive capsulitis evaluated. Gadolinium injection did not increase the performance of the inferior glenohumeral ligament signal analysis. An extracapsular hyperintense layer on T2-weighted images was identified as a new sign of adhesive capsulitis. T2 capsular signal intensity change offers a high performance for the diagnosis of adhesive capsulitis without the need for IV or intraarticular contrast injection.

  15. MR signal-fat-fraction analysis and T2* weighted imaging measure BAT reliably on humans without cold exposure.

    Science.gov (United States)

    Holstila, Milja; Pesola, Marko; Saari, Teemu; Koskensalo, Kalle; Raiko, Juho; Borra, Ronald J H; Nuutila, Pirjo; Parkkola, Riitta; Virtanen, Kirsi A

    2017-05-01

    Brown adipose tissue (BAT) is compositionally distinct from white adipose tissue (WAT) in terms of triglyceride and water content. In adult humans, the most significant BAT depot is localized in the supraclavicular area. Our aim is to differentiate brown adipose tissue from white adipose tissue using fat T2* relaxation time mapping and signal-fat-fraction (SFF) analysis based on a commercially available modified 2-point-Dixon (mDixon) water-fat separation method. We hypothesize that magnetic resonance (MR) imaging can reliably measure BAT regardless of the cold-induced metabolic activation, with BAT having a significantly higher water and iron content compared to WAT. The supraclavicular area of 13 volunteers was studied on 3T PET-MRI scanner using T2* relaxation time and SFF mapping both during cold exposure and at ambient temperature; and 18 F-FDG PET during cold exposure. Volumes of interest (VOIs) were defined semiautomatically in the supraclavicular fat depot, subcutaneous WAT and muscle. The supraclavicular fat depot (assumed to contain BAT) had a significantly lower SFF and fat T2* relaxation time compared to subcutaneous WAT. Cold exposure did not significantly affect MR-based measurements. SFF and T2* values measured during cold exposure and at ambient temperature correlated inversely with the glucose uptake measured by 18 F-FDG PET. Human BAT can be reliably and safely assessed using MRI without cold activation and PET-related radiation exposure. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. 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.

  17. Phenols as Diamagnetic T2-Exchange Magnetic Resonance Imaging Contrast Agents.

    Science.gov (United States)

    Zhang, Jia; Li, Yuguo; Slania, Stephanie; Yadav, Nirbhay N; Liu, Jing; Wang, Rongfu; Zhang, Jianhua; Pomper, Martin G; van Zijl, Peter C; Yang, Xing; Liu, Guanshu

    2018-01-26

    Although T 2 -exchange (T 2ex ) NMR phenomena have been known for decades, there has been a resurgence of interest to develop T 2ex MRI contrast agents. One indispensable advantage of T 2ex MR agents is the possibility of using non-toxic and/or bio-compatible diamagnetic compounds with intermediate exchangeable protons. Herein a library of phenol-based compounds is screened and their T 2ex contrast (exchange relaxivity, r 2ex ) at 9.4 T determined. The T 2ex contrast of phenol protons allows direct detection by MRI at a millimolar concentration level. The effect of chemical modification of the phenol on the T 2ex MRI contrast through modulation of exchange rate and chemical shift was also studied and provides a guideline for use of endogenous and exogenous phenols for T 2ex MRI contrast. As a proof-of-principle application, phenol T 2ex contrast can be used to detect enzyme activity in a tyrosinase-catalyzed catechol oxidation reaction. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. 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

  19. 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.

  20. 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

    , Niels Uldbjerg6, Anne Sørensen1, 4 INSTITUTIONS (ALL): 1. Department of Obstetrics and Gynecology, Aalborg University Hospital, Aalborg, Denmark. 2. Department of Clinical Engineering, Central Denmark Region, Aarhus, Denmark. 3. Department of Radiology, Aalborg University Hospital, Aalborg, Denmark. 4...... was a selected, mixed population regarding the risk of low birth weight. According to our national guidelines, pregnancies with ultrasound estimated fetal weight (EFW) pregnancies at 20-40 weeks' gestation, of which 68 had an EFW ≥ -15% and 28...... using a non-linear least squares fitting algorithm. Placental T2* Z-scores were calculated using a linear regression model based on normal pregnancies previously published by our group. We defined low birth weight by a Z-score

  1. Do spotty high intensity regions found in basal ganglia on MRI T2-weighted brain images of elderly subjects indicate gliosis? Comparison of brain MRI T2-weighted images of elderly subjects and necropsy brain

    International Nuclear Information System (INIS)

    Murai, Hiroshi; Hattori, Hideyuki; Matsumoto, Masayuki

    2001-01-01

    Spotty high intensity regions are frequently found on the MRI T2-weighted brain images (T2WI) of elderly people. High intensity regions with a diameter of 3 mm or less have been considered as expanded perivascular space with no pathological implications on radiological diagnosis. However, its morphometrical basis is not clear. We examined the character of the spotty regions using brain MRI of brain screening subjects, and studied morphometrically arteriolosclerosis and perivascular tissue damage using necropsy brains of subjects aged 65 years and over. The size, number and location of the spotty high intensity regions were examined using the brain MRI of 109 T2WI which is used for brain screening at Kanazawa Medical University Hospital. The frontal lobe, temporal lobe, parietal lobe, hippocampus, midbrain and basal ganglia were sampled from 15 subjects aged 65 years and over, and the tissue sections were processed for HE stain, Elastica van Gieson stain and immunostaining with GFAP. We took photographs of brain arterioli and surrounding parenchyma with a digital telescope camera and the degree of arterioscleosis and tissue damage were assessed by measurements with an image analyzer. Spotty high intensity regions on T2WI with a diameter of 3 mm or less were observed in 95.5% subjects aged 65 years and over. 69.4% spotty region was observed in basal ganglia. There was a significant correlation between age and size. In morphometrical examination, at the basal ganglia, the density of GFAP-positive astrocytes in the perivascular tissue had a significant positive correlation with the proportional thickness of the adventitia, which is an index of arteriosclerosis, and a significant negative correlation with the size of the perivascular space. The results suggested that the spotty regions in the brain MRI of elderly people do not represent dilatations of the perivascular space, but is mild brain damage caused by arteriosclerosis. (author)

  2. Magnetic Properties of the Ternary Compounds CeT2Si2 and UT2Si2

    NARCIS (Netherlands)

    Palstra, T.T.M.; Menovsky, A.A.; Nieuwenhuys, G.J.; Mydosh, J.A.

    1986-01-01

    We have investigated the magnetic properties of the intermetallic compounds CeT2Si2 and UT2Si2, with T a transition metal. From our measurements we have determined a trend from Pauli-paramagnetism via antiferromagnetism to canted antiferromagnetism with increasing number of d-electrons.

  3. Entropy of T2-weighted imaging combined with apparent diffusion coefficient in prediction of uterine leiomyoma volume response after uterine artery embolization.

    Science.gov (United States)

    Cao, Meng-Qiu; Suo, Shi-Teng; Zhang, Xue-Bin; Zhong, Yi-Cun; Zhuang, Zhi-Guo; Cheng, Jie-Jun; Chi, Jia-Chang; Xu, Jian-Rong

    2014-04-01

    To determine the potential value of entropy of T2-weighted imaging combined with apparent diffusion coefficient (ADC) before uterine artery embolization (UAE) for prediction of uterine leiomyoma volume reduction (VR) after UAE. In this prospective study, 11 patients with uterine leiomyomas who underwent pelvic magnetic resonance imaging including diffusion-weighted imaging before and 6 months after UAE were included. A total number of 16 leiomyomas larger than 2 cm in diameter were evaluated. The volume of each leiomyoma before and after UAE was determined, and the percentage change in volume was calculated. Entropy of T2-weighted imaging and ADC before UAE were assessed. Pearson correction coefficients were calculated between leiomyoma VR after UAE and age, leiomyoma volume, ADC, and entropy, respectively. Multiple regression analysis was performed to investigate the parameters that determine the VR after UAE. Receiver operating characteristic curve analysis was used to determine the sensitivity and specificity of ADC, entropy and the combination of ADC and entropy for predicting volume response. The mean leiomyoma VR was 58.9% (range 25.8%-95.0%) in the 6-month follow-up. The mean ADC of leiomyomas was 1.37 × 10(-3) mm(2)/s (range 1.05 × 10(-3)-2.32 × 10(-3) mm(2)/s) and the mean entropy of T2-weighted imaging was 5.36 (range 4.62-5.91) before UAE. ADC and entropy were significantly correlated with leiomyoma VR, respectively (r = 0.61, P = .012; r = 0.73, P = .001). On multiple regression analysis, a combination of ADC and entropy constituted the best model for determining leiomyoma VR using Akaike information criterion. For predicting ≥50% VR, the optimal cutoff value of ADC was 1.39 × 10(-3) mm(2)/s (sensitivity 45.5%, specificity 80.0%) and the optimal cutoff value of entropy was 5.15 (sensitivity 90.9%, specificity 60.0%). The combination of ADC and entropy (area under the curve [AUC] 0.86) provided better classification accuracy than ADC or entropy

  4. Heavily T2 weighted MR assessment of fornical injury after anterior interhemispheric approach for large suprasellar tumors

    International Nuclear Information System (INIS)

    Saeki, N.; Kubota, M.; Murai, H.; Yamaura, A.; Sunami, K.; Uozumi, A.

    2001-01-01

    Fornical injury in transforaminal approach is well known. Its injury in the anterior interhemispheric approach (AIA) has been rarely highlighted. We report 2 cases with a large suprasellar tumor who underwent AIA. Postoperative heavily T2 weighted reversed (T2R) MR images demonstrated its unilateral injury. The clinical significance of symptom-free fornical injury after AIA is discussed. Cases 1 and 2 were a 15 year-old girl with a meningioma and a 49-year-old woman with a craniopharyngioma, respectively. They underwent AIA. Postoperative T2R images revealed unilateral fornical crus atrophy. They did not present associated memory deficits. Case 1 had the injury of both fornical column and anterior commissure. They were speculatively torn by intra-operative lateral retraction of the frontal lobes. Case 2 had unilateral atrophy of the mammillary body and postcommissural fornix, which were probably caused by ischemic damage related to surgical manipulation, since case 2 had an associated anterior thalamic infarct. During the Operation for large suprasellar tumors, excessive laterally directed brain retraction should be avoided, since such manipulation may easily tear the overstretched anterior commissure and fornical column. Once we notice or suspect fornical injury an MR studies in cases of re-operation, we have to choose a surgical approach and operative manipulation to preserve an intact fornix. The MR evaluation of fornix should be included in the peri-operative radiological assessment, since patients with unilateral fornical injury were free of memory disturbance, and T2R imaging is a useful MR sequence for depicting the anatomy related to the fornix. (author)

  5. Single Breath-Hold Physiotherapy Technique; Effective tool for T2* magnetic resonance imaging in young patients with thalassaemia major

    Directory of Open Access Journals (Sweden)

    Surekha T. Mevada

    2016-02-01

    Full Text Available Magnetic resonance imaging using T2* (MRI T2* is a highly sensitive and non-invasive technique for the detection of tissue iron load. Although the single breath-hold multi-echo T2* technique has been available at the Sultan Qaboos University Hospital (SQUH, Muscat, Oman, since 2006, it could not be performed on younger patients due to their inability to hold their breath after expiration. This study was carried out between May 2007 and May 2015 and assessed 50 SQUH thalassaemic patients aged 7‒17 years old. Seven of these patients underwent baseline and one-year follow-up MRI T2* scans before receiving physiotherapy training. Subsequently, all patients were trained by a physiotherapist to hold their breath for approximately 15‒20 seconds at the end of expiration before undergoing baseline and one-year follow-up MRI T2* scans. Failure rates for the pre- and post-training groups were 6.0% and 42.8%, respectively. These results indicate that the training of thalassaemic patients in breathhold techniques is beneficial and increases rates of compliance for MRI T2* scans.

  6. Magnetic resonance fingerprinting using echo-planar imaging: Joint quantification of T1and 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.

  7. Synthesis of Ferromagnetic Fe0.6 Mn0.4 O Nanoflowers as a New Class of Magnetic Theranostic Platform for In Vivo T1 -T2 Dual-Mode Magnetic Resonance Imaging and Magnetic Hyperthermia Therapy.

    Science.gov (United States)

    Liu, Xiao Li; Ng, Cheng Teng; Chandrasekharan, Prashant; Yang, Hai Tao; Zhao, Ling Yun; Peng, Erwin; Lv, Yun Bo; Xiao, Wen; Fang, Jie; Yi, Jia Bao; Zhang, Huan; Chuang, Kai-Hsiang; Bay, Boon Huat; Ding, Jun; Fan, Hai Ming

    2016-08-01

    Uniform wüstite Fe0.6 Mn0.4 O nanoflowers have been successfully developed as an innovative theranostic agent with T1 -T2 dual-mode magnetic resonance imaging (MRI), for diagnostic applications and therapeutic interventions via magnetic hyperthermia. Unlike their antiferromagnetic bulk counterpart, the obtained Fe0.6 Mn0.4 O nanoflowers show unique room-temperature ferromagnetic behavior, probably due to the presence of an exchange coupling effect. Combined with the flower-like morphology, ferromagnetic Fe0.6 Mn0.4 O nanoflowers are demonstrated to possess dual-modal MRI sensitivity, with longitudinal relaxivity r1 and transverse relaxivity r2 as high as 4.9 and 61.2 mm(-1) s(-1) [Fe]+[Mn], respectively. Further in vivo MRI carried out on the mouse orthotopic glioma model revealed gliomas are clearly delineated in both T1 - and T2 -weighted MR images, after administration of the Fe0.6 Mn0.4 O nanoflowers. In addition, the Fe0.6 Mn0.4 O nanoflowers also exhibit excellent magnetic induction heating effects. Both in vitro and in vivo magnetic hyperthermia experimentation has demonstrated that magnetic hyperthermia by using the innovative Fe0.6 Mn0.4 O nanoflowers can induce MCF-7 breast cancer cell apoptosis and a complete tumor regression without appreciable side effects. The results have demonstrated that the innovative Fe0.6 Mn0.4 O nanoflowers can be a new magnetic theranostic platform for in vivo T1 -T2 dual-mode MRI and magnetic thermotherapy, thereby achieving a one-stop diagnosis cum effective therapeutic modality in cancer management. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. 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

  9. 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.

  10. MR imaging of compressive cervical myelopathy after surgery; High signal intensity of the spinal cord on T2 weighted images

    Energy Technology Data Exchange (ETDEWEB)

    Mimura, Fumitoshi; Fujiwara, Kazuhisa; Otake, Shoichiro (Tenri Hospital, Nara (Japan)) (and others)

    1990-06-01

    We reviewed the MR images of 32 patients with cervical myelopathy, showing lesions of high signal intensity in the spinal cord on the sagittal T2 weighted images (T2WI) after surgery: 16 with ossification of posterior longitudinal ligament (OPLL); 9 with spondylosis; 4 with disc herniation and 3 with trauma. All images were obtained on a superconducting 1.5 Tesla system. The lesions were classified into five groups, according to the shape and grade of signal intensity on the sagittal T2WI: (I) oval-shaped lesion of signal intensity less brighter than CSF with blurred margin, (II) longitudinal linear-shaped lesion of signal intensity similar to CSF, (III) spindle-shaped lesion of signal intensity similar to CSF, (IV) round-shaped lesion of signal intensity similar to CSF, and (V) mixed-types lesions which consisted of group I and II. The present study was summarized as follows: Oval-shaped lesions were seen in the cases of disc herniation and spondylosis with relatively short duration of the symptom, presumptively with relatively short duration of the symptom, presumptively indicative of edema. Most cases of OPLL and spondylosis showed linear-shaped lesions, suggesting necrosis and/or cavitations of the central gray matter. One case of spondylosis developed a spindle-shaped lesion, implicating syringomyelia. Round-shaped lesions were seen in the cases of spinal trauma, suggesting postraumatic cyst. In a case of mixed-typed lesion examined pre- and postoperatively, only an oval-shaped lesion decreased in size after surgery. (author).

  11. Dynamics of unloaded and green tea extract loaded lecithin based liposomal dispersions investigated by nuclear magnetic resonance T2relaxation.

    Science.gov (United States)

    Kirtil, Emrah; Dag, Damla; Guner, Selen; Unal, Kubra; Oztop, Mecit H

    2017-09-01

    Liposomes are lipid bilayer vesicles that can be used as encapsulation systems for bioactive agents to provide increased protection against environmental stresses (such as pH or temperature extremes). Time Domain Nuclear Magnetic Resonance (TD-NMR) that is based on differentiation of specimen contents with respect to magnetic relaxation rates provides detailed information on amount, state and distribution of water and oil and provide reproducible results on the samples. These make TD-NMR particularly suitable for time-dependent monitoring of emulsion system dynamics. In this study, spin-spin (T 2 ) relaxation times and relaxation spectra were used for characterizing green tea extract loaded and unloaded liposomes prepared with soy (S75) and egg lecithins (E80) by different preparation methods (such as homogenization type, pressure and solvent type). Mean particle sizes of liposomes were found to be the most influential factor in shaping mono-exponential T 2 relaxation times. The differences in particle sizes of E80 and S75 samples along with samples with different homogenization pressures could be monitored with T 2 relaxation times. Additionally, T 2 relaxation times were found to be correlated with particle shape irregularity, and chemical instability of samples due to lipid oxidation. With relaxation spectrum analysis, particular components in the sample could be distinguished (internal/external water and lipid bilayers), which gave more elaborate results on mechanisms of instability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Braking due to non-resonant magnetic perturbations and comparison with neoclassical toroidal viscosity torque in EXTRAP T2R

    Science.gov (United States)

    Frassinetti, L.; Sun, Y.; Fridström, R.; Menmuir, S.; Olofsson, K. E. J.; Brunsell, P. R.; Khan, M. W. M.; Liang, Y.; Drake, J. R.

    2015-09-01

    The non-resonant magnetic perturbation (MP) braking is studied in the EXTRAP T2R reversed-field pinch (RFP) and the experimental braking torque is compared with the torque expected by the neoclassical toroidal viscosity (NTV) theory. The EXTRAP T2R active coils can apply magnetic perturbations with a single harmonic, either resonant or non-resonant. The non-resonant MP produces velocity braking with an experimental torque that affects a large part of the core region. The experimental torque is clearly related to the plasma displacement, consistent with a quadratic dependence as expected by the NTV theory. The work show a good qualitative agreement between the experimental torque in a RFP machine and NTV torque concerning both the torque density radial profile and the dependence on the non-resonant MP harmonic.

  13. 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

  14. Optimization image of magnetic resonance imaging (MRI) T2 fast spin echo (FSE) with variation echo train length (ETL) on the rupture tendon achilles case

    Science.gov (United States)

    Muzamil, Akhmad; Haries Firmansyah, Achmad

    2017-05-01

    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 (pTendon 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.

  15. Foci of decreased signal on T2-weighted MR images in leiomyosarcomas of soft tissue: correlation between MR and histological findings

    Energy Technology Data Exchange (ETDEWEB)

    Pilavaki, M. E-mail: mayiapil@otenet.gr; Drevelegas, A.; Nenopoulou, H.; Scordalaki, A.; Chourmouzi, D.; Sofroniadis, I.; Dimitriadis, A.S

    2004-09-01

    Objective: Leiomyosarcomas are rare soft tissue sarcomas with varying MR signal characteristics and histologic pictures. The purpose of this study was to investigate the histological features of foci, which showed decreased signal on T2-weighted images in leiomyosarcomas of soft tissue. Material and methods: We reviewed the MR images of six histologically proved cases of leiomyosarcomas of soft tissue and correlated the foci, which showed decreased signal on T2-weighted images with the histologic findings. Result: Microscopic examination revealed that these foci were composed of hyalinization of neoplastic tissue, internal septations, deposition of hemosiderin, or corresponded to metaplastic bone. Conclusion: The authors explain that the foci of decreased signal on T2-weighted MR images correspond to tissue components of the lesion, particularly fibrous tissue, hemosiderin and metaplastic bone. So, the suggestion is that leiomyosarcoma should be considered in the differential diagnosis of soft-tissue tumors that show foci of decreased signal on T2-weighted MR images.

  16. Significance of T2 Hyperintensity on Magnetic Resonance Imaging After Cervical Cord Injury and Return to Play in Professional Athletes.

    Science.gov (United States)

    Tempel, Zachary J; Bost, Jeffrey W; Norwig, John A; Maroon, Joseph C

    2015-07-01

    Cervical cord magnetic resonance imaging (MRI) T2 hyperintensity is used as evidence of cord trauma in the evaluation and management of athletes in contact sports. The long-term pathophysiologic and prognostic value of this finding is poorly understood, especially in return to play (RTP). To examine the significance of T2 hyperintensity in the cervical spinal cord of professional athletes. Retrospective review of MRI T2 hyperintensity findings between 2007 and 2014 in 5 professional athletes. Pertinent examination and demographics, including mechanism of injury, surgical intervention, radiographs, MRI studies, long-term outcomes, and RTP recommendations were collected. Four National Football League players and 1 professional wrestler had prior traumatic neurapraxia that at the time of initial consultation had resolved. MRIs showed congenitally small cervical canal (1) and multilevel spondylosis/stenosis/disc herniation (4) along with focal cord T2 hyperintensity (5). The signal abnormalities were at C3/C4 (3), C4 mid-vertebral body (1), and C5/C6 (1). Four athletes had single-level anterior cervical discectomy and fusion, and 1 was nonoperative. Serial MRI imaging at 3 months after surgery showed hyperintensity partially resolved (4) and unchanged (1), and at 9-months 3 of the 5 completely resolved. Based on the author's RTP criteria, 4 of 5 were released to return to their sport. Clearance for RTP preceded complete resolution of MRI T2 hyperintensity in 3 of 4 athletes. The 2 athletes that have returned to profession sport have not had any additional episodes of neurapraxia or any cervical spine-related complications. MRI T2 hyperintensity in contact sport athletes who are symptom-free with normal examination and no evidence of spinal instability may not be a contraindication to RTP. Additional observations are needed to confirm this observation.

  17. 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.)

  18. 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.)

  19. Building a high-resolution T2-weighted MR-based probabilistic model of tumor occurrence in the prostate.

    Science.gov (United States)

    Nagarajan, Mahesh B; Raman, Steven S; Lo, Pechin; Lin, Wei-Chan; Khoshnoodi, Pooria; Sayre, James W; Ramakrishna, Bharath; Ahuja, Preeti; Huang, Jiaoti; Margolis, Daniel J A; Lu, David S K; Reiter, Robert E; Goldin, Jonathan G; Brown, Matthew S; Enzmann, Dieter R

    2018-02-19

    We present a method for generating a T2 MR-based probabilistic model of tumor occurrence in the prostate to guide the selection of anatomical sites for targeted biopsies and serve as a diagnostic tool to aid radiological evaluation of prostate cancer. In our study, the prostate and any radiological findings within were segmented retrospectively on 3D T2-weighted MR images of 266 subjects who underwent radical prostatectomy. Subsequent histopathological analysis determined both the ground truth and the Gleason grade of the tumors. A randomly chosen subset of 19 subjects was used to generate a multi-subject-derived prostate template. Subsequently, a cascading registration algorithm involving both affine and non-rigid B-spline transforms was used to register the prostate of every subject to the template. Corresponding transformation of radiological findings yielded a population-based probabilistic model of tumor occurrence. The quality of our probabilistic model building approach was statistically evaluated by measuring the proportion of correct placements of tumors in the prostate template, i.e., the number of tumors that maintained their anatomical location within the prostate after their transformation into the prostate template space. Probabilistic model built with tumors deemed clinically significant demonstrated a heterogeneous distribution of tumors, with higher likelihood of tumor occurrence at the mid-gland anterior transition zone and the base-to-mid-gland posterior peripheral zones. Of 250 MR lesions analyzed, 248 maintained their original anatomical location with respect to the prostate zones after transformation to the prostate. We present a robust method for generating a probabilistic model of tumor occurrence in the prostate that could aid clinical decision making, such as selection of anatomical sites for MR-guided prostate biopsies.

  20. Contrasting weight changes with LY2605541, a novel long-acting insulin, and insulin glargine despite similar improved glycaemic control in T1DM and T2DM.

    Science.gov (United States)

    Jacober, S J; Rosenstock, J; Bergenstal, R M; Prince, M J; Qu, Y; Beals, J M

    2014-04-01

    The basal insulin analogue LY2605541, a PEGylated insulin lispro with prolonged duration of action, was previously shown to be associated with modest weight loss in Phase 2, randomized, open-label trials in type 2 (N=288) and type 1 (N=137) diabetes mellitus (T2DM and T1DM), compared with modest weight gain with insulin glargine. Exploratory analyses were conducted to further characterize these findings. Pearson correlations between change in body weight and other variables were calculated. Continuous variables were analysed using a mixed linear model with repeated measurements. Proportions of subjects with weight loss were analysed using Fisher's exact test for T2DM and Nagelkerke's method for T1DM. Weight loss was more common in LY2605541-treated patients than in patients treated with insulin glargine (T2DM: 56.9 vs. 40.2%, p=0.011; T1DM: 66.1 vs. 40.3%, pT2DM: 4.8 vs. 0%, p=0.033; T1DM: 11.9 vs. 0.8%, pT2DM studies, weight change did not correlate with baseline body mass index (BMI), or change in HDL-cholesterol in either treatment group. No consistent correlations were found across both studies between weight change and any of the variables assessed; however, weight change was significantly correlated with hypoglycaemia rate in glargine-treated T2DM patients. In two Phase 2 trials, improved glycaemic control with long-acting basal insulin analogue LY2605541 is associated with weight loss in previously insulin-treated patients. This weight change is independent of baseline BMI or hypoglycaemia.

  1. Diagnosis of complications associated with acute cholecystitis using computed tomography and diffusion-weighted imaging with background body signal suppression/T2 image fusion

    Science.gov (United States)

    Tomizawa, Minoru; Shinozaki, Fuminobu; Tanaka, Satomi; Sunaoshi, Takafumi; Kano, Daisuke; Sugiyama, Eriko; Shite, Misaki; Haga, Ryouta; Fukamizu, Yoshiya; Fujita, Toshiyuki; Kagayama, Satoshi; Hasegawa, Rumiko; Shirai, Yoshinori; Motoyoshi, Yasufumi; Sugiyama, Takao; Yamamoto, Shigenori; Ishige, Naoki

    2017-01-01

    In a clinical setting, it is important to diagnose complications of acute cholecystitis accurately. Diffusion-weighted whole body imaging with background body signal suppression/T2-weighted image fusion (DWIBS/T2) provides high signal intensity with a strong contrast against surrounding tissues in anatomical settings. In the present study, patients who were being treated for acute cholecystitis and underwent DWIBS/T2 in the National Hospital Organization Shimoshizu Hospital between December 2012 and August 2015 were enrolled. A total of 10 men and 4 women underwent DWIBS/T2. Records, including DWIBS/T2 and computed tomography (CT) imaging, were retrospectively analyzed for patients with acute cholecystitis. CT images revealed thickened gallbladder walls in patients with acute cholecystitis, and high signal intensity was observed in DWIBS/T2 images for the thickened gallbladder wall. Inflammation of the pericholecystic space and the liver resulted in high intensity signals with DWIBS/T2 imaging, whereas CT imaging revealed a low-density area in the cholecystic space. Plain CT scanning identified a low-density area in the liver, which became more obvious with contrast-enhanced CT. DWIBS/T2 imaging showed the inflammation of the liver and pericholesyctic space as an area of high signal intensity. Detectability of inflammation of the pericholecystic space and the liver was the same for DWIBS/T2 and CT, which suggests that DWIBS/T2 has the same sensitivity as CT scanning for the diagnosis of complicated acute cholecystitis. However, the strong contrast shown by DWIBS/T2 allows for easier evaluation of acute cholecystitis than CT scanning. PMID:28672993

  2. Imaging of VSOP labeled stem cells in agarose phantoms with susceptibility weighted and T2* weighted MR Imaging at 3T: determination of the detection limit.

    Directory of Open Access Journals (Sweden)

    Donald Lobsien

    Full Text Available OBJECTIVES: This study aimed to evaluate the detectability of stem cells labeled with very small iron oxide particles (VSOP at 3T with susceptibility weighted (SWI and T2* weighted imaging as a methodological basis for subsequent examinations in a large animal stroke model (sheep. MATERIALS AND METHODS: We examined ovine mesenchymal stem cells labeled with VSOP in agarose layer phantoms. The experiments were performed in 2 different groups, with quantities of 0-100,000 labeled cells per layer. 15 different SWI- and T2*-weighted sequences and 3 RF coils were used. All measurements were carried out on a clinical 3T MRI. Images of Group A were analyzed by four radiologists blinded for the number of cells, and rated for detectability according to a four-step scale. Images of Group B were subject to a ROI-based analysis of signal intensities. Signal deviations of more than the 0.95 confidence interval in cell containing layers as compared to the mean of the signal intensity of non cell bearing layers were considered significant. RESULTS: GROUP A: 500 or more labeled cells were judged as confidently visible when examined with a SWI-sequence with 0.15 mm slice thickness. Group B: 500 or more labeled cells showed a significant signal reduction in SWI sequences with a slice thickness of 0.25 mm. Slice thickness and cell number per layer had a significant influence on the amount of detected signal reduction. CONCLUSION: 500 VSOP labeled stem cells could be detected with SWI imaging at 3 Tesla using an experimental design suitable for large animal models.

  3. Effect of magnetic boundary on edge plasma profiles studied using probe measurements in EXTRAP T2R

    OpenAIRE

    Moustaphawi, Hawra

    2012-01-01

    In this Master’s thesis project, several experiments are conducted under three different conditions in order to study their effect on the edge plasma profiles. In the first case, the standard case, there is no external interference and the plasma is studied under normal lab environments. In the second case, the plasma position inside the EXTRAP T2R device is changed by a few millimeters and in the third case a magnetic boundary is inserted into the experiment. For each set of the experiment, ...

  4. 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)

  5. Driven equilibrium (drive) MR imaging of the cranial nerves V-VIII: comparison with the T2-weighted 3D TSE sequence.

    Science.gov (United States)

    Ciftci, E; Anik, Yonca; Arslan, Arzu; Akansel, Gur; Sarisoy, Tahsin; Demirci, Ali

    2004-09-01

    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. 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 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. 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.

  6. 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.)

  7. T2 corrected quantification method of L-p-boronophenylalanine using proton magnetic resonance spectroscopy for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Yamamoto, Yohei; Isobe, Tomonori; Yamamoto, Tetsuya; Shibata, Yasushi; Anno, Izumi; Nakai, Kei; Shirakawa, Makoto; Matsushita, Akira; Sato, Eisuke; Matsumura, Akira

    2009-01-01

    In the present study, we aimed to evaluate a T2 corrected quantification method of L-p-boronophenylalanine (BPA) concentration using proton magnetic resonance spectroscopy (MRS). We used five phantoms containing BPA (1.5, 3.0, 5.0, 7.5, and 10 mmol/kg=15, 30, 50, 75, and 100 μg 10 B/g), N-acetyl-aspartic acid (NAA: 3.0 mmol/kg), creatine (Cr: 5.0 mmol/kg), and choline (Cho: 3.0 mmol/kg). The signal intensities of BPA and internal water were corrected by T2 relaxation time. The absolute concentrations of BPA were calculated by proton MRS using an internal water signal as a standard. The major BPA peaks were detected between 7.1 and 7.6 ppm. Mean T2 relaxation time was 314.3±10.8 ms in BPA, 885.1±39.7 ms in internal water. The calculated BPA concentrations were almost same as the actual concentration of BPA and the correlation coefficient was 0.99. Our BPA quantification method was very simple and non-invasive, also it had high accuracy. Therefore, our results indicate that proton MRS can be potentially useful technique for in vivo BPA quantification in boron neutron capture therapy (BNCT).

  8. Hepatic magnetic resonance imaging with T2* mapping of ovariectomized rats: correlation between iron overload and postmenopausal osteoporosis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lingshan; Peng, Xingui; Wang, Yuancheng; Wang, Yaling; Chen, Min; Wang, Qi; Jin, Jiyang [Zhongda Hospital of Southeast University, Department of Radiology, Nanjing (China); Zhu, Zhengqiu [Zhongda Hospital of Southeast University, Department of Endocrinology, Nanjing (China)

    2014-07-15

    To explore the correlation between liver iron overload and bone mineral density (BMD) in an ovariectomy (OVX) rat model, using liver magnetic resonance (MR)-T2* and dual-energy X-ray absorptiometry (DEXA). Sprague-Dawley rats received deferoxamine (DFO) or phosphate-buffered saline 3 months after bilateral OVX. MRI and DEXA were performed pre- and postoperatively. Five rats per group were killed every month for micro-CT, histopathology and biochemical examinations. Statistical analysis was performed with independent-samples t tests, box plots and Pearson's correlation analysis. At 2 months postoperatively, BMD was significantly lower in the OVX group than in the control group (P < 0.01), corresponding to the increased serum ferritin concentration (SFC; P < 0.01) and liver iron concentration (LIC; P < 0.01). Liver T2* values significantly differed between the two groups at 1 month postoperatively (P < 0.001) and improved 1 month after DFO injection (P < 0.05). These values were significantly and positively correlated with BMD in the control (r = 0.527, P < 0.001) and OVX (r = 0.456, P < 0.001) groups. Liver MRI T2* changed markedly earlier than BMD, LIC and SFC, and correlated well with osteoporosis; it may thus be a valuable early indicator of osteoporosis. (orig.)

  9. Measurement of the exchange rate of waters of hydration in elastin by 2D T2-T2 correlation nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Sun Cheng; Boutis, Gregory S

    2011-01-01

    We report on a direct measurement of the exchange rate of waters of hydration in elastin by T 2 -T 2 exchange spectroscopy. The exchange rates in bovine nuchal ligament elastin and aortic elastin at temperatures near, below and at the physiological temperature are reported here. Using an inverse Laplace transform (ILT) algorithm, we are able to identify four components in the relaxation times. While three of the components are in good agreement with previous measurements that used multi-exponential fitting, the ILT algorithm distinguishes a fourth component having relaxation times close to that of free water and is identified as water between fibers. With the aid of scanning electron microscopy, a model is proposed that allows for the application of a two-site exchange analysis between any two components for the determination of exchange rates between reservoirs. The results of the measurements support a model (described by Urry and Parker 2002 J. Muscle Res. Cell Motil. 23 543-59) wherein the net entropy of waters of hydration should increase with increasing temperature in the inverse temperature transition.

  10. 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

  11. Focal treatment or observation of prostate cancer: pretreatment accuracy of transrectal ultrasound biopsy and T2-weighted MRI.

    Science.gov (United States)

    Nogueira, Lucas; Wang, Liang; Fine, Samson W; Pinochet, Rodrigo; Kurta, Jordan M; Katz, Darren; Savage, Caroline J; Cronin, Angel M; Hricak, Hedvig; Scardino, Peter T; Akin, Oguz; Coleman, Jonathan A

    2010-02-01

    To test the hypothesis that men with prostate cancer (PCA) and preoperative disease features considered favorable for focal treatment would be accurately characterized with transrectal biopsy and prostate magnetic resonance imaging (MRI) by performing a retrospective analysis of a selected cohort of such patients treated with radical prostatectomy (RP). A total of 202 patients with PCA who had preoperative MRI and low-risk biopsy criteria (no Gleason grade 4/5, 1 involved core, < 2 mm, PSA density < or = 0.10, clinical stage < or = T2a) were included in the study. Indolent RP pathology was defined as no Gleason 4/5, organ confined, tumor volume < 0.5 mL, and negative surgical margins. MRI ability to locate and determine the tumor extent was assessed. After RP, 101 men (50%) had nonindolent cancer. Multifocal and bilateral tumors were present in 81% and 68% of patients, respectively. MRI indicated extensive disease in 16 (8%). MRI sensitivity to locate PCA ranged from 2% to 20%, and specificity from 91% to 95%. On univariate analysis, MRI evidence of extracapsular extension (P = .027) and extensive disease (P = .001) were associated with nonindolent cancer. On multivariate analysis, only the latter remained as significant predictor (P = .0018). Transrectal biopsy identified men with indolent tumors favorable for focal treatment in 50% of cases. MRI findings of extracapsular extension and extensive tumor involving more than half of the gland are associated with unfavorable features, and may be useful in excluding patients from focal treatment. According to these data, endorectal MRI is not sufficient to localize small tumors for focal treatment. 2010 Elsevier Inc. All rights reserved.

  12. Myocardium at risk in ST-segment elevation myocardial infarction comparison of T2-weighted edema imaging with the MR-assessed endocardial surface area and validation against angiographic scoring.

    Science.gov (United States)

    Fuernau, Georg; Eitel, Ingo; Franke, Vinzenz; Hildebrandt, Lysann; Meissner, Josefine; de Waha, Suzanne; Lurz, Philipp; Gutberlet, Matthias; Desch, Steffen; Schuler, Gerhard; Thiele, Holger

    2011-09-01

    The objective of this study was to assess the area at risk (AAR) in ST-segment elevation myocardial infarction with 2 different cardiac magnetic resonance (CMR) imaging methods and to compare them with the validated angiographic Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease Score (APPROACH-score) in a large consecutive patient cohort. Edema imaging with T(2)-weighted CMR and the endocardial surface area (ESA) assessed by late gadolinium enhancement have been introduced as relatively new methods for AAR assessment in ST-segment elevation myocardial infarction. However, data on the utility and validation of these techniques are limited. A total of 197 patients undergoing primary percutaneous coronary intervention in acute ST-segment elevation myocardial infarction were included. AAR (assessed with T(2)-weighted edema imaging and the ESA method), infarct size, and myocardial salvage (AAR minus infarct size) were determined by CMR 2 to 4 days after primary angioplasty. Angiographic AAR scoring was performed by use of the APPROACH-score. All measurements were done offline by blinded observers. The AAR assessed by T(2)-weighted imaging showed good correlation with the angiographic AAR (r = 0.87; p myocardial salvage index. In contrast, no dependence of T(2)-weighted edema imaging or the APPROACH-score on myocardial salvage index was seen. The AAR can be reliably assessed by T(2)-weighted CMR, whereas assessment of the AAR by ESA seems to be dependent on the degree of myocardial salvage, thereby underestimating the AAR in patients with high myocardial salvage such as aborted infarction. Thus, assessment of the AAR with the ESA method cannot be recommended. (Myocardial Salvage and Contrast Dye Induced Nephropathy Reduction by N-Acetylcystein [LIPSIA-N-ACC]; NCT00463749). Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  13. MRI of acute post-ischemic cerebral hemorrhage in stroke patients: diagnosis with T2{sup *}-weighted gradient-echo sequences

    Energy Technology Data Exchange (ETDEWEB)

    Hermier, M. [Dept. of Radiology, Univ. Claude-Bernard Lyon-I (France); Centre de Recherche et d' Application en Traitement de l' Image et du Signal (CREATIS), UMR CNRS Lyon (France); Service de Radiologie, Hopital Neurologique, Lyon (France); Nighoghossian, N. [Centre de Recherche et d' Application en Traitement de l' Image et du Signal (CREATIS), UMR CNRS Lyon (France); Cerebrovascular Disease and Ataxia Research Center, Univ. Claude-Bernard Lyon-I, Lyon (France); Derex, L.; Blanc-Lasserre, K.; Trouillas, P. [Cerebrovascular Disease and Ataxia Research Center, Univ. Claude-Bernard Lyon-I, Lyon (France); Berthezene, Y. [Centre de Recherche et d' Application en Traitement de l' Image et du Signal (CREATIS), UMR CNRS Lyon (France); Dept. of Radiology, Univ. Claude-Bernard Lyon-I, Lyon (France); Froment, J.C. [Dept. of Radiology, Univ. Claude-Bernard Lyon-I (France); Centre de Recherche et d' Application en Traitement de l' Image et du Signal (CREATIS), UMR CNRS Lyon (France)

    2001-10-01

    The use of T2{sup *}-weighted sequences has been advocated for early differentiation between hematoma and ischemia in patients with acute stroke. Early hemorrhagic transformation of ischemic stroke is an adverse event which may occur under treatment and may impair the prognosis: our aim is to evaluate the ability of T2*-weighted gradient-echo sequence (T2{sup *} GRE) to detect post-ischemic cerebral hemorrhage. The imaging procedure included: (1) baseline CT scan at admission. (2) MRI performed within 24 h of therapy onset including: (a) dual fast spin echo T2 sequence, (b) axial isotropic echoplanar diffusion-weighted imaging sequence, (c) conventional T2* GRE, and (d) 3D TOF turbo MRA. Post-ischemic cerebral hemorrhage was diagnosed if T2{sup *} GRE detected a focal intraparenchymal area of signal loss. The diameter of this lesion had to be more than 5 mm in order to eliminate past microbleeds. (3) Patients who showed an early suspicion of bleeding on MRI promptly had a second CT scan, and, if this one was negative for bleeding, another CT scan was performed 1 day later. All the other patients had a control CT scan during the first week. Forty-five consecutive patients have been included. T2* GRE showed intracranial bleeding in seven. The diagnosis of post-ischemic cerebral bleeding was confirmed by CT in all patients. Control CT scans did not reveal any post-ischemic cerebral hemorrhage in patients with negative MRI. In one case, hemorrhage was seen earlier on MRI than on CT scan. In conclusion, T2{sup *} GRE appeared to be at least as efficient as CT scan in the detection of early post-ischemic cerebral hemorrhage. (orig.)

  14. Dynamic contrast-enhanced imaging has limited added value over T2-weighted imaging and diffusion-weighted imaging when using PI-RADSv2 for diagnosis of clinically significant prostate cancer in patients with elevated PSA.

    Science.gov (United States)

    De Visschere, P; Lumen, N; Ost, P; Decaestecker, K; Pattyn, E; Villeirs, G

    2017-01-01

    To determine the added value of dynamic contrast-enhanced imaging (DCE) over T2-weighted imaging (T2-WI) and diffusion-weighted imaging (DWI) for detection of clinically significant prostate cancer (csPC) in patients with elevated prostate-specific antigen (PSA). Two hundred and forty-five patients with elevated PSA underwent multiparametric (mp) magnetic resonance imaging (MRI) of the prostate before biopsy. mpMRI was performed using a 3 T MRI system without an endorectal coil. Patients underwent transrectal ultrasound-guided systematic 12 core biopsy followed by radical prostatectomy (n=68), radiation therapy (n=91), or clinical follow-up for at least 2 years (n=86). csPC was defined as Gleason score ≥3+4 and/or tumour volume of ≥0.5 ml, and/or tumour stage ≥T3a. The MRI findings were scored according to the Prostate Imaging Reporting and Data System version 2 (PI-RADSv2) and an alternative overall assessment category (PI-RADSv2Alt) based on only T2-WI and DWI. In 144 patients (58.8%), csPC was found within 2 years after MRI. With scoring according to the PI-RADSv2 guidelines, DCE was not needed for determination of the overall assessment category in 80.8% (198/245) of patients. Receiver operating characteristic (ROC) analysis showed an area under the curve of 0.79 (95% confidence interval [CI]: 0.74-0.85) for PI-RADSv2 and 0.79 (95% CI: 0.73-0.85) for PI-RADSv2Alt. The added value of DCE over T2-WI and DWI is limited when using PI-RADSv2 for diagnosis of csPC in patients with elevated PSA before biopsy. An alternative overall assessment score using only T2-WI and DWI yielded similar performance to PI-RADSv2. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  15. Optimized T1- and T2-weighted volumetric brain imaging as a diagnostic tool in very preterm neonates

    Energy Technology Data Exchange (ETDEWEB)

    Nossin-Manor, Revital [Neurosciences and Mental Health, Research Institute, Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto (Canada); Chung, Andrew D.; Morris, Drew; Thomas, Bejoy; Shroff, Manohar M. [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Soares-Fernandes, Joao P. [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Hospital de S. Marcos, Neuroradiology Department, Braga (Portugal); Cheng, Hai-Ling M. [The Hospital for Sick Children, Department of Diagnostic Imaging, Physiology Experimental Medicine, Research Institute, Toronto (Canada); University of Toronto, Medical Biophysics Department, Toronto (Canada); Whyte, Hilary E.A. [Neurosciences and Mental Health, Research Institute, Neonatology Department, The Hospital for Sick Children, Toronto (Canada); Taylor, Margot J. [The Hospital for Sick Children, Neurosciences and Mental Health, Research Institute, Department of Diagnostic Imaging, Toronto (Canada); University of Toronto, Medical Imaging, Toronto (Canada); Sled, John G. [University of Toronto, Physiology Experimental Medicine, Research Institute, The Hospital for Sick Children, Medical Biophysics, Toronto (Canada)

    2011-06-15

    T1- and T2-W MR sequences used for obtaining diagnostic information and morphometric measurements in the neonatal brain are frequently acquired using different imaging protocols. Optimizing one protocol for obtaining both kinds of information is valuable. To determine whether high-resolution T1- and T2-W volumetric sequences optimized for preterm brain imaging could provide both diagnostic and morphometric value. Thirty preterm neonates born between 24 and 32 weeks' gestational age were scanned during the first 2 weeks after birth. T1- and T2-W high-resolution sequences were optimized in terms of signal-to-noise ratio, contrast-to-noise ratio and scan time and compared to conventional spin-echo-based sequences. No differences were found between conventional and high-resolution T1-W sequences for diagnostic confidence, image quality and motion artifacts. A preference for conventional over high-resolution T2-W sequences for image quality was observed. High-resolution T1 images provided better delineation of thalamic myelination and the superior temporal sulcus. No differences were found for detection of myelination and sulcation using conventional and high-resolution T2-W images. High-resolution T1- and T2-W volumetric sequences can be used in clinical MRI in the very preterm brain to provide both diagnostic and morphometric information. (orig.)

  16. Optimized T1- and T2-weighted volumetric brain imaging as a diagnostic tool in very preterm neonates

    International Nuclear Information System (INIS)

    Nossin-Manor, Revital; Chung, Andrew D.; Morris, Drew; Thomas, Bejoy; Shroff, Manohar M.; Soares-Fernandes, Joao P.; Cheng, Hai-Ling M.; Whyte, Hilary E.A.; Taylor, Margot J.; Sled, John G.

    2011-01-01

    T1- and T2-W MR sequences used for obtaining diagnostic information and morphometric measurements in the neonatal brain are frequently acquired using different imaging protocols. Optimizing one protocol for obtaining both kinds of information is valuable. To determine whether high-resolution T1- and T2-W volumetric sequences optimized for preterm brain imaging could provide both diagnostic and morphometric value. Thirty preterm neonates born between 24 and 32 weeks' gestational age were scanned during the first 2 weeks after birth. T1- and T2-W high-resolution sequences were optimized in terms of signal-to-noise ratio, contrast-to-noise ratio and scan time and compared to conventional spin-echo-based sequences. No differences were found between conventional and high-resolution T1-W sequences for diagnostic confidence, image quality and motion artifacts. A preference for conventional over high-resolution T2-W sequences for image quality was observed. High-resolution T1 images provided better delineation of thalamic myelination and the superior temporal sulcus. No differences were found for detection of myelination and sulcation using conventional and high-resolution T2-W images. High-resolution T1- and T2-W volumetric sequences can be used in clinical MRI in the very preterm brain to provide both diagnostic and morphometric information. (orig.)

  17. MRI of the normal brain from early childhood to middle age. Pt. 2. Age dependence of signal intensity changes on T2-weighted images

    International Nuclear Information System (INIS)

    Autti, T.; Raininko, R.; Vanhanen, S.L.; Kallio, M.; Santavuori, P.

    1994-01-01

    We examined 66 healthy volunteers aged 4 to 50 years by magnetic resonance imaging (MRI) and the signal intensity was measured on T2-weighted images in numerous sites and correlated with age and sex. Using distilled water and cerebrospinal fluid (CSF) as references on each slice, we calculated the signal intensities of the brain structures. Calculated ratios between structures did not change with age, except for those of the globus pallidus and thalamus, in which the signal intensities decreased more rapidly. The signal intensities of other brain structures changed equally but this could not be discerned visually and quantitative measurements were required. The signal intensities in the white and deep grey matter decreased rapidly in the first decade and then gradually to reach a plateau after the age of 18 years. Maturation of the brain thus seems to continue until near the end of the second decade of life. No sex differences were found. Quantitative analysis requires intensity references. The CSF in the tips of the frontal horns seems to be as reliable as an external fluid reference for intensity, and can be used in routine examinations provided the frontal horns are large enough to avoid partial volume effect. (orig.)

  18. Relationship between myocardial T2* values and cardiac volumetric and functional parameters in β-thalassemia patients evaluated by cardiac magnetic resonance in association with serum ferritin levels

    International Nuclear Information System (INIS)

    Liguori, Carlo; Pitocco, Francesca; Di Giampietro, Ilenia; Vivo, Aldo Eros de; Schena, Emiliano; Cianciulli, Paolo; Zobel, Bruno Beomonte

    2013-01-01

    Purpose: Myocardial T2* cardiovascular magnetic resonance provides a rapid and reproducible assessment of cardiac iron load in thalassemia patients. Although cardiac involvement is mainly characterized by left ventricular dysfunction caused by iron overload, little is known about right ventricular function. The aim of this study was to assess the relationship between T2* value in myocardium and left–right ventricular volumetric and functional parameters and to evaluate the existing associations between left–right ventricles volumetric and functional parameter, myocardial T2* values and blood ferritin levels. Materials and methods: A retrospective analysis of 208 patients with β-thalassemia major and thalassemia intermedia was performed (109 males and 99 females; mean age 37.7 ± 13 years; 143 thalassemia major, 65 thalassemia intermedia). Myocardial iron load was assessed by T2* measurements, and volumetric functions were analyzed using the steady state free precession sequence. Results: A significant correlation was observed between EFLV and T2* (p = 0.0001), EFRV and T2* (p = 0.0279). An inverse correlation was present between DVLV and T2* (p = 0.0468), SVLV and T2* (p = 0.0003), SVRV and T2* (p = 0.0001). There was no significant correlation between cardiac T2* and LV–RV mass indices. A significant correlation was observed between T2* and serum ferritin levels (p < 0.001) and between EFLV and serum ferritin (p < 0.05). Conclusion: Myocardial iron load assessed by T2* cardiac magnetic resonance is associated with deterioration in left–right ventricular function; this is more evident when T2* values fall below 14 ms. CMR appears to be a promising approach for cardiac risk evaluation in TM patients

  19. Relationship between myocardial T2* values and cardiac volumetric and functional parameters in β-thalassemia patients evaluated by cardiac magnetic resonance in association with serum ferritin levels

    Energy Technology Data Exchange (ETDEWEB)

    Liguori, Carlo, E-mail: c.liguori@unicampus.it [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Pitocco, Francesca, E-mail: f.pitocco@unicampus.it [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Di Giampietro, Ilenia, E-mail: i.digiampietro@unicampus.it [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Vivo, Aldo Eros de, E-mail: devivoeros@gmail.com [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Schena, Emiliano, E-mail: e.schena@unicampus.it [Unit of Measurements and Biomedical Instrumentation, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Cianciulli, Paolo, E-mail: CIANCIULLI.PAOLO@aslrmc.it [Thalassemia Unit, Ospedale Sant Eugenio, Piazzale dell’Umanesimo 10, 00143 Rome (Italy); Zobel, Bruno Beomonte, E-mail: b.zobel@unicampus.it [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy)

    2013-09-15

    Purpose: Myocardial T2* cardiovascular magnetic resonance provides a rapid and reproducible assessment of cardiac iron load in thalassemia patients. Although cardiac involvement is mainly characterized by left ventricular dysfunction caused by iron overload, little is known about right ventricular function. The aim of this study was to assess the relationship between T2* value in myocardium and left–right ventricular volumetric and functional parameters and to evaluate the existing associations between left–right ventricles volumetric and functional parameter, myocardial T2* values and blood ferritin levels. Materials and methods: A retrospective analysis of 208 patients with β-thalassemia major and thalassemia intermedia was performed (109 males and 99 females; mean age 37.7 ± 13 years; 143 thalassemia major, 65 thalassemia intermedia). Myocardial iron load was assessed by T2* measurements, and volumetric functions were analyzed using the steady state free precession sequence. Results: A significant correlation was observed between EFLV and T2* (p = 0.0001), EFRV and T2* (p = 0.0279). An inverse correlation was present between DVLV and T2* (p = 0.0468), SVLV and T2* (p = 0.0003), SVRV and T2* (p = 0.0001). There was no significant correlation between cardiac T2* and LV–RV mass indices. A significant correlation was observed between T2* and serum ferritin levels (p < 0.001) and between EFLV and serum ferritin (p < 0.05). Conclusion: Myocardial iron load assessed by T2* cardiac magnetic resonance is associated with deterioration in left–right ventricular function; this is more evident when T2* values fall below 14 ms. CMR appears to be a promising approach for cardiac risk evaluation in TM patients.

  20. T2*-based MR imaging (gradient echo or susceptibility-weighted imaging) in midline and off-midline intracranial germ cell tumors. A pilot study

    International Nuclear Information System (INIS)

    Morana, Giovanni; Tortora, Domenico; Severino, Mariasavina; Rossi, Andrea; Alves, Cesar Augusto; Finlay, Jonathan L.; Nozza, Paolo; Ravegnani, Marcello; Pavanello, Marco; Milanaccio, Claudia; Garre, Maria Luisa; Maghnie, Mohamad

    2018-01-01

    The role of T2*-based MR imaging in intracranial germ cell tumors (GCTs) has not been fully elucidated. The aim of this study was to evaluate the susceptibility-weighted imaging (SWI) or T2* gradient echo (GRE) features of germinomas and non-germinomatous germ cell tumors (NGGCTs) in midline and off-midline locations. We retrospectively evaluated all consecutive pediatric patients referred to our institution between 2005 and 2016, for newly diagnosed, treatment-naive intracranial GCT, who underwent MRI, including T2*-based MR imaging (T2* GRE sequences or SWI). Standard pre- and post-contrast T1- and T2-weighted imaging characteristics along with T2*-based MR imaging features of all lesions were evaluated. Diagnosis was performed in accordance with the SIOP CNS GCT protocol criteria. Twenty-four subjects met the inclusion criteria (17 males and 7 females). There were 17 patients with germinomas, including 5 basal ganglia primaries, and 7 patients with secreting NGGCT. All off-midline germinomas presented with SWI or GRE hypointensity; among midline GCT, all NGGCTs showed SWI or GRE hypointensity whereas all but one pure germinoma were isointense or hyperintense to normal parenchyma. A significant difference emerged on T2*-based MR imaging among midline germinomas, NGGCTs, and off-midline germinomas (p < 0.001). Assessment of the SWI or GRE characteristics of intracranial GCT may potentially assist in differentiating pure germinomas from NGGCT and in the characterization of basal ganglia involvement. T2*-based MR imaging is recommended in case of suspected intracranial GCT. (orig.)

  1. 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.

  2. 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.)

  3. 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.)

  4. Hysteresis in the tearing mode locking/unlocking due to resonant magnetic perturbations in EXTRAP T2R

    Science.gov (United States)

    Fridström, R.; Frassinetti, L.; Brunsell, P. R.

    2015-10-01

    The physical mechanisms behind the hysteresis in the tearing mode locking and unlocking to a resonant magnetic perturbation (RMP) are experimentally studied in EXTRAP T2R reversed-field pinch. The experiments show that the electromagnetic and the viscous torque increase with increasing perturbation amplitude until the mode locks to the wall. At the wall-locking, the plasma velocity reduction profile is peaked at the radius where the RMP is resonant. Thereafter, the viscous torque drops due to the relaxation of the velocity in the central plasma. This is the main reason for the hysteresis in the RMP locking and unlocking amplitude. The increased amplitude of the locked tearing mode produces further deepening of the hysteresis. Both experimental results are in qualitative agreement with the model in Fitzpatrick et al (2001 Phys. Plasmas 8 4489)

  5. The extent of myocardium at Risk for LAD, RCA and LCx using contrast enhanced SSFP and T2-weighted imaging

    DEFF Research Database (Denmark)

    Nordlund, D.; Heiberg, E.; Carlsson, Marcus

    2015-01-01

    (12 excluded due to missing data, 53 due to inability to detect MaR) were included. Late gadolinium enhancement (LGE) imaging was used to assess infarct size. Imaging was performed on systems from three different vendors (Siemens, Philips, GE) and data was analyzed by a core laboratory. Culprit vessel...... was determined using angiography. Results: Average size of MaR was greater for LAD (CE-SSFP: 44+/-10%, T2w: 44+/-9% of the left ventricle [LV], p-value LV) and RCA (CE-SSFP: 31+/-7%, T2w: 30+/-8% of the LV). A comparison of coronary perfusion...

  6. 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

  7. 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.

  8. 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.)

  9. MRI differential diagnosis of complete and partial tears of the anterior cruciate ligament of the knee: the usefulness of oblique coronal T2-weighted image

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seo Young; Shim, Jae Chan; Lee, Ghi Jai; Bang, Sun Woo; Ryu, Seok Jong; Kim, Ho Kyun [College of Medicine, Inje Univ., Kimhae (Korea, Republic of); Kim, Jeong Seok [College of Medicine, Dongguk Univ., Seoul (Korea, Republic of)

    2002-04-01

    To assess the usefulness of T2-weighted oblique coronal MR imaging (T2OCI) in the differential diagnosis of complete and partial tears of the anterior cruciate ligament (ACL) of the knee. Thirty-three patients with ACL tear (16 complete and 17 partial tears), comfirmed by arthroscopy, were included in this study. Conventional MR imaging and T2OCI were performed, and the findings were retrospectively reviewed by two radiologists in terms of continuity, shape, axis and internal signal intensity of the ligament. Each finding was tested if there were stastistically significant differences in its prevalence between partial and complete tears. The diagnostic accuracy of T2OCI and conventional MR imaging in the detection of partial and complete tears of the ACL were compared. Conventional MR imaging revealed no statistically significant finding for differential diagnosis of complete and partial ACL tears. The reliable and statistically significant (p<0.001) findings of T2OCI were complete discontinuity of the ligament in cases involving complete ACL tears (14 of 16 complete tears and 2 of 17 partial tears) and the preservation of the band form for partial ACL tears (2 of 16 complete tears and 15 of 17 partial tears). The accuracy of T2OCI and conventional MR imaging was 88% and 70%, respectively. When ACL injury is vague on conventional MR images, a modality which is more useful in the differential diagnosis of partial and complete tears of the ACL, and in predicting the site of a tear, is T2-weighted oblique coronal imaging.

  10. Additional values of high-resolution gadoxetic acid-enhanced MR cholangiography for evaluating the biliary anatomy of living liver donors: Comparison with T2-weighted MR cholangiography and conventional gadoxetic acid-enhanced MR cholangiography.

    Science.gov (United States)

    Kang, Hyo-Jin; Lee, Jeong Min; Yoon, Jeong Hee; Joo, Ijin; Chang, Won; Suh, Kyung-Suk; Lee, Kwang-Woong; Yi, Nam-Joon; Han, Joon Koo

    2018-01-01

    To determine the incremental value of small field of view (sFOV) high-resolution (HR) gadoxetic acid-enhanced 3D T 1 -weighted (W) magnetic resonance cholangiography (MRC) for evaluating the biliary anatomy of potential living donors by comparing it to T 2 W-MRC. In all, 73 living donor candidates underwent gadoxetic acid-enhanced MRI (3.0T) including three kinds of MRCs: 3D multislice T 2 W-MRC, regular FOV (rFOV) (380 × 380mm, resolution 1.0 × 1.2 × 3.0 mm) 3D T 1 W-MRC, and sFOV (256 × 208 mm, resolution 1.0 × 1.0 × 1.0 mm) HR-T 1 W-MRC. Three radiologists reviewed the image sets for the visibility of segmental intrahepatic bile ducts (BDs), biliary anatomy with its confidence level, and expected number of BD openings at right hemihepatectomy. Compared to T 2 W-MRC alone, the combination of sFOV HR-T 1 W-MRC and T 2 W-MRC (sT 1 W-HR set) yielded significantly improved BD visibility scores (P W set (rFOV T 1 W-MRC with T 2 W MRC), the sFOV HR set showed significantly increased caudate duct visibility (P W-MRC presenting subdiagnostic image quality, the addition of sFOV HRT 1 W-MRC provided diagnostically acceptable image visibility (53.8∼90%) to all reviewers. The addition of sFOV HR-T 1 W-MRC resulted in a significantly higher consistency with the operative record and expected number of BD openings than did T 2 W-MRC alone (P W-MRC sets. The combination of sFOV HR-T 1 W-MRC and T 2 W-MRC significantly improved BD visibility and confidence levels for biliary anatomy compared to T 2 W-MRC alone, thereby allowing accurate biliary anatomy assessment in most patients with subdiagnostic T 2 W-MRC images. 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:152-159. © 2017 International Society for Magnetic Resonance in Medicine.

  11. Pulmonary nodule detection in oncological patients - Value of respiratory-triggered, periodically rotated overlapping parallel T2-weighted imaging evaluated with PET/CT-MR.

    Science.gov (United States)

    de Galiza Barbosa, Felipe; Geismar, Jan Henning; Delso, Gaspar; Messerli, Michael; Huellner, Martin; Stolzmann, Paul; Veit-Haibach, Patrick

    2018-01-01

    To prospectively evaluate the detection and conspicuity of pulmonary nodules in an oncological population, using a tri-modality PET/CT-MR protocol including a respiration-gated T2-PROPELLER sequence for possible integration into a simultaneous PET/MR protocol. 149 patients referred for staging of malignancy were prospectively enrolled in this single-center study. Imaging was performed on a tri-modality PET/CT-MR setup and was comprised of PET/CT and 3T-MR imaging with 3D dual-echo GRE pulse sequence (Dixon) and an axial respiration-gated T2-weighted PROPELLER (T2-P) sequence. Images were assessed for presence, conspicuity, size and interpretation of the pulmonary parenchymal nodules. McNemar's test was used to evaluate paired differences in nodule detection rates between MR and CT from PET/CT. The correlation of pulmonary nodule size in CT and MR imaging was assessed using Pearson correlation coefficient. 299 pulmonary nodules were detected on PET/CT. The detectability was significantly higher on T2-P (60%, p10mm were detected equally well with T2-P (92.2%) and CT (p >0.05). In a per-patient analysis, there was no significant change in the clinical interpretation of the nodules detected with T2-P and CT. Despite the overall lower detection rate compared with CT, the free-breathing respiratory gating T2-w sequence showed higher detectability in all evaluated categories compared to breath-hold T1-weighted MR sequences. Specifically, the T2-P was found to be not statistically different from CT in FDG-positive nodules, in detection of nodules >10mm and concerning conspicuity of pulmonary nodules. Overall, the additional time investment into T2-P seems to be justified since clinical relevant assessment of pulmonary lung nodules can mostly be done by T2-P in a whole body PET/MR staging of oncologic patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. 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 volumetric analysis of the kidney in native 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.

  13. Quantification of myocardial oxygenation in heart failure using blood-oxygen-level-dependent T2* magnetic resonance imaging: Comparison with cardiopulmonary exercise test.

    Science.gov (United States)

    Nagao, Michinobu; Yamasaki, Yuzo; Kawanami, Satoshi; Kamitani, Takeshi; Sagiyama, Koji; Higo, Taiki; Ide, Tomomi; Takemura, Atsushi; Ishizaki, Umiko; Fukushima, Kenji; Watanabe, Yuji; Honda, Hiroshi

    2017-06-01

    Quantification of myocardial oxygenation (MO) in heart failure (HF) has been less than satisfactory. This has necessitated the use of invasive techniques to measure MO directly or to determine the oxygen demand during exercise using the cardiopulmonary exercise (CPX) test. We propose a new quantification method for MO using blood-oxygen-level-dependent (BOLD) myocardial T2* magnetic resonance imaging (M-T2* MRI), and investigate its correlation with CPX results. Thirty patients with refractory HF who underwent cardiac MRI and CPX test for heart transplantation, and 24 healthy, age-matched volunteers as controls were enrolled. M-T2* imaging was performed using a 3-Tesla and multi-echo gradient-echo sequence. M-T2* was calculated by fitting the signal intensity data for the mid-left ventricular septum to a decay curve. M-T2* was measured under room-air (T2*-air) and after inhalation of oxygen for 10min at a flow rate of 10L/min (T2*-oxy). MO was defined as the difference between the two values (ΔT2*). Changes in M-T2* at the two conditions and ΔT2* between the two groups were compared. Correlation between ΔT2* and CPX results was analyzed using the Pearson coefficient. T2*-oxy was significantly greater than T2*-air in patients with HF (29.9±7.3ms vs. 26.7±6.0ms, p<0.001), whereas no such difference was observed in controls (25.5±4.0ms vs. 25.4±4.4ms). ΔT2* was significantly greater for patients with HF than for controls (3.2±4.5ms vs. -0.1±1.3ms, p<0.001). A significant correlation between ΔT2* and CPX results (peak VO 2 , r=-0.46, p<0.05; O 2 pulse, r=-0.54, p<0.005) was observed. ΔT2* is increased T2*-oxy is greater in patients with HF, and is correlated with oxygen metabolism during exercise as measured by the CPX test. Hence, ΔT2* can be used as a surrogate marker of MO instead of CPX test. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. 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

  15. Cerebral and meningeal manifestations of AIDS: comparison of plain T2-weighted images and Gd-DTPA enhanced T1-weighted images in 105 patients; Zerebrale und meningeale Manifestationen des AIDS: Vergleich von nativer T2-gewichteter und Gd-DTPA unterstuetzter T1-gewichteter MRT (105 Patienten)

    Energy Technology Data Exchange (ETDEWEB)

    Jochens, R. [Strahlenklinik und Poliklinik, Universitaetsklinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Henkes, H. [Klinik fuer Radiologische Diagnostik und Neuroradiologie, Alfried Krupp Krankenhaus, Essen (Germany); Steinkamp, H.J. [Strahlenklinik und Poliklinik, Universitaetsklinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Terstegge, K. [Strahlenklinik und Poliklinik, Universitaetsklinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Hosten, N. [Strahlenklinik und Poliklinik, Universitaetsklinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Ruf, B. [II. Medizinische Klinik, Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin, Standort Wedding (Germany); Schoerner, W. [Inst. fuer Roentgendiagnostik und Nuklearmedizin, Staedtisches Klinikum, Braunschweig (Germany)

    1994-12-31

    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%. 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) [Deutsch] Den Stellenwert der T1-gewichteten Gd-DTPA unterstuetzten MRT im

  16. 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 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. Fortschr R

  17. Sensitivity and specificity of unenhanced MR mammography (DWI combined with T2-weighted TSE imaging, ueMRM) for the differentiation of mass lesions

    Energy Technology Data Exchange (ETDEWEB)

    Baltzer, Pascal A.T.; Benndorf, Matthias; Dietzel, Matthias; Kaiser, Werner A. [Friedrich Schiller University Jena, Institute of Diagnostic and Interventional Radiology, Jena (Germany); Gajda, Mieczyslaw [Institute of Pathology, Friedrich Schiller University Jena, Jena (Germany); Camara, Oumar [Friedrich Schiller University Jena, Clinic of Gynecology, Jena (Germany)

    2010-05-15

    This study was performed to assess the sensitivity and specificity for malignant and benign mass lesions of a diagnostic approach combining DWI with T2-weighted images (unenhanced MR mammography, ueMRM) and compare the results with contrast-enhanced MR mammography (ceMRM). Consecutive patients undergoing histopathological verification of mass lesions after MR mammography without prior breast interventions (contrast-enhanced T1-weighted, T2-weighted and DWI sequences) were eligible for this retrospective investigation. Two blinded observers first rated ueMRM and then ceMRM according to the BIRADS scale. Lesion size, ADC values and T2-weighted TSE descriptors were assessed. This study examined 81 lesions (27 benign, 54 malignant). Sensitivity of ueMRM was 93% (observer 1) and 86% (observer 2), respectively. Sensitivity of ceMRM was 96.5% (observer 1) and 98.3% (observer 2). Specificity was 85.2% (ueMRM) and 92.6% (ceMRM) for both observers. The differences between both methods and observers were not significant (P {>=} 0.09). Lesion size measurements did not differ significantly among all sequences analyzed. Tumor visibility was worse using ueMRM for both benign (P < 0.001) and malignant lesions (P = 0.004). Sensitivity and specificity of ueMRM in mass lesions equal that of ceMRM. However, a reduced lesion visibility in ueMRM may lead to more false-negative findings. (orig.)

  18. 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.

  19. 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 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 trials.

  20. Automatic Brain Tumor Detection in T2-weighted Magnetic Resonance Images

    Czech Academy of Sciences Publication Activity Database

    Dvořák, Pavel; Kropatsch, W.G.; Bartušek, Karel

    2013-01-01

    Roč. 13, č. 5 (2013), s. 223-230 ISSN 1335-8871 R&D Projects: GA ČR GAP102/12/1104; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : Brain tumor * Brain tumor detection * Symmetry analysis Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.162, year: 2013

  1. Role of Diffusion-Weighted Magnetic Resonance Imaging in Diffuse Axonal Injury

    Energy Technology Data Exchange (ETDEWEB)

    Ezaki, Y.; Tsutsumi, K.; Morikawa, M.; Nagata, I. [Nagasaki Univ., Graduate School of Medicine (Japan). Depts. of Neurosurgery and Radiology

    2006-09-15

    Purpose: To determine whether the signal changes on magnetic resonance imaging (MRI), including fluid attenuated inversion recovery (FLAIR), T2*-weighted gradient echo (GE) imaging, and diffusion-weighted imaging (DWI) in diffuse axonal injury (DAI) patients correlate with the clinical outcome. Material and Methods: We diagnosed patients with DAI based on the following criteria: 1) a loss of consciousness from the time of injury that persisted beyond 6 h; 2) no apparent hemorrhagic contusion on computed tomography (CT); 3) the presence of white matter injury on MRI. Twenty-one DAI patients were analyzed (19 M, 2 F, mean age 34 years) with MRI (FLAIR, T2*-weighted GE imaging, and DWI). Results: 325 abnormalities were detected by MRI within a week after injury. The T2*-weighted GE imaging was significantly more sensitive than FLAIR and DWI in diagnosing DAI. DWI detected only 32% of all lesions, but could depict additional shearing injuries not visible on either T2*-weighted GE imaging or FLAIR. The mean number of lesions in brainstem detected by DWI in the favorable group (good recovery/moderately disabled) was significantly smaller than in the unfavorable group (severely disabled/vegetative survival/death). This trend was not observed on the T2*-weighted GE imaging and FLAIR findings. Conclusion: DWI cannot detect all DAI-related lesions, but is a potentially useful imaging modality for both diagnosing and assessing patients with DAI.

  2. Quantitative texture analysis of brain white matter lesions derived from T2-weighted MR images in MS patients with clinically isolated syndrome.

    Science.gov (United States)

    Loizou, C P; Petroudi, S; Seimenis, I; Pantziaris, M; Pattichis, C S

    2015-04-01

    This study investigates the application of texture analysis methods on brain T2-white matter lesions detected with magnetic resonance imaging (MRI) for the prognosis of future disability in subjects diagnosed with clinical isolated syndrome (CIS) of multiple sclerosis (MS). Brain lesions and normal appearing white matter (NAWM) from 38 symptomatic untreated subjects diagnosed with CIS as well as normal white matter (NWM) from 20 healthy volunteers, were manually segmented, by an experienced MS neurologist, on transverse T2-weighted images obtained from serial brain MR imaging scans (0 and 6-12 months). Additional clinical information in the form of the Expanded Disability Status Scale (EDSS), a scale from 0 to 10, which provides a way of quantifying disability in MS and monitoring the changes over time in the level of disability, were also provided. Shape and most importantly different texture features including GLCM and laws were then extracted for all above regions, after image intensity normalization. The findings showed that: (i) there were significant differences for the texture futures extracted between the NAWM and lesions at 0 month and between NAWM and lesions at 6-12 months. However, no significant differences were found for all texture features extracted when comparing lesions temporally at 0 and 6-12 months with the exception of contrast (gray level difference statistics-GLDS) and difference entropy (spatial gray level dependence matrix-SGLDM); (ii) significant differences were found between NWM and NAWM for most of the texture features investigated in this study; (iii) there were significant differences found for the lesion texture features at 0 month for those with EDSS≤2 versus those with EDSS>2 (mean, median, inverse difference moment and sum average) and for the lesion texture features at 6-12 months with EDSS>2 and EDSS≤2 for the texture features (mean, median, entropy and sum average). It should be noted that whilst there were no differences

  3. 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

  4. Apparent diffusion coefficient for prediction of parametrial invasion in cervical cancer: a critical evaluation based on stratification to a Likert scale using T2-weighted imaging.

    Science.gov (United States)

    Woo, Sungmin; Kim, Sang Youn; Cho, Jeong Yeon; Kim, Seung Hyup

    2018-03-01

    To evaluate the value of apparent diffusion coefficient (ADC) for determining parametrial invasion (PMI) in cervical cancer, by stratifying them into subgroups based on a Likert scale using T2-weighted imaging (T2WI). This retrospective study included 87 patients with FIGO stage IA2-IIB cervical cancer who underwent preoperative MRI followed by radical hysterectomy. Radiological PMI was assessed on T2WI using a six-point Likert scale and ADC values of the tumors were measured. MRI findings were compared between patients with and without PMI. Differences in ADC according to the Likert scale were also assessed. 19 (21.8%) patients had pathological PMI. The prevalence of PMI was significantly associated with Likert scale (P PMI had significantly lower ADC values than those without PMI (P = 0.034). However, no significant difference was seen between patients with and without PMI within each Likert score group (P = 0.180-0.857). T2WI-based Likert score for radiological PMI and ADC values of the tumor were significantly associated with pathological PMI. However, the apparent association seen between ADC values and PMI may be due to contribution of high ADC values of MRI-invisible tumors rather than reflecting their relationship.

  5. Linear signal hyperintensity adjacent to the subchondral bone plate at the knee on T2-weighted fat-saturated sequences: imaging aspects and association with structural lesions

    International Nuclear Information System (INIS)

    Gondim Teixeira, Pedro Augusto; Balaj, Clemence; Marie, Beatrice; Lecocq, Sophie; Louis, Matthias; Blum, Alain; Braun, Marc

    2014-01-01

    To describe the association between linear T2 signal abnormalities in the subchondral bone and structural knee lesions. MR studies of patients referred for the evaluation of knee pain were retrospectively evaluated and 133 of these patients presented bone marrow edema pattern (BMEP) (study group) and while 61 did not (control group). The presence of linear anomalies of the subchondral bone on T2-weighted fat-saturated sequences was evaluated. The findings were correlated to the presence of structural knee lesions and to the duration of the patient's symptoms. Histologic analysis of a cadaveric specimen was used for anatomic correlation. Linear T2 hyperintensities at the subchondral bone were present in 41 % of patients with BMEP. None of the patients in the control group presented this sign. When a subchondral linear hyperintensity was present, the prevalence of radial or root tears was high and that of horizontal tears was low (71.4 and 4.8 %, respectively). Sixty-nine percent of the patients with a subchondral insufficiency fracture presented a subchondral linear hyperintensity. It was significantly more prevalent in patients with acute or sub-acute symptoms (p < 0.0001). The studied linear T2 hyperintensity is located at the subchondral spongiosa and can be secondary to local or distant joint injuries. Its presence should evoke acute and sub-acute knee injuries. This sign is closely related to subchondral insufficiency fractures and meniscal tears with a compromise in meniscal function. (orig.)

  6. Linear signal hyperintensity adjacent to the subchondral bone plate at the knee on T2-weighted fat-saturated sequences: imaging aspects and association with structural lesions

    Energy Technology Data Exchange (ETDEWEB)

    Gondim Teixeira, Pedro Augusto; Balaj, Clemence [CHU Hopital Central, Service D' Imagerie Guilloz, Nancy (France); Universite de Lorraine, IADI, UMR S 947, Nancy (France); Marie, Beatrice [CHU Hopital Central, Service d' Anatomo-Pathologie, Nancy (France); Lecocq, Sophie; Louis, Matthias; Blum, Alain [CHU Hopital Central, Service D' Imagerie Guilloz, Nancy (France); Braun, Marc [CHU Hopital Central, Service de Neuroradiologie, Nancy (France)

    2014-11-15

    To describe the association between linear T2 signal abnormalities in the subchondral bone and structural knee lesions. MR studies of patients referred for the evaluation of knee pain were retrospectively evaluated and 133 of these patients presented bone marrow edema pattern (BMEP) (study group) and while 61 did not (control group). The presence of linear anomalies of the subchondral bone on T2-weighted fat-saturated sequences was evaluated. The findings were correlated to the presence of structural knee lesions and to the duration of the patient's symptoms. Histologic analysis of a cadaveric specimen was used for anatomic correlation. Linear T2 hyperintensities at the subchondral bone were present in 41 % of patients with BMEP. None of the patients in the control group presented this sign. When a subchondral linear hyperintensity was present, the prevalence of radial or root tears was high and that of horizontal tears was low (71.4 and 4.8 %, respectively). Sixty-nine percent of the patients with a subchondral insufficiency fracture presented a subchondral linear hyperintensity. It was significantly more prevalent in patients with acute or sub-acute symptoms (p < 0.0001). The studied linear T2 hyperintensity is located at the subchondral spongiosa and can be secondary to local or distant joint injuries. Its presence should evoke acute and sub-acute knee injuries. This sign is closely related to subchondral insufficiency fractures and meniscal tears with a compromise in meniscal function. (orig.)

  7. 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

  8. Does T2 mapping of the posterior annulus fibrosus indicate the presence of lumbar intervertebral disc herniation? A 3.0 Tesla magnetic resonance study.

    Science.gov (United States)

    Messner, Alina; Stelzeneder, David; Trattnig, Stefan; Welsch, Götz H; Schinhan, Martina; Apprich, Sebastian; Brix, Martin; Windhager, Reinhard; Trattnig, Siegfried

    2017-03-01

    Indicating lumbar disc herniation via magnetic resonance imaging (MRI) T2 mapping in the posterior annulus fibrosus (AF). Sagittal T2 maps of 313 lumbar discs of 64 patients with low back pain were acquired at 3.0 Tesla (3T). The discs were rated according to disc herniation and bulging. Region of interest (ROI) analysis was performed on median, sagittal T2 maps. T2 values of the AF, in the most posterior 10% (PAF-10) and 20% of the disc (PAF-20), were compared. A significant increase in the T2 values of discs with herniations affecting the imaged area, compared to bulging discs and discs with lateral herniation, was shown in the PAF-10, where no association to the NP was apparent. The PAF-20 exhibited a moderate correlation to the nucleus pulposus (NP). High T2 values in the PAF-10 suggest the presence of disc herniation (DH). The results indicate that T2 values in the PAF-20 correspond more to changes in the NP.

  9. Contrast-optimized composite image derived from multigradient echo cardiac magnetic resonance imaging improves reproducibility of myocardial contours and T2*measurement

    NARCIS (Netherlands)

    Triadyaksa, Pandji; Handayani, Astri; Dijkstra, Hildebrand; Aryanto, Kadek Y. E.; Pelgrim, Gert Jan; Xie, Xueqian; Willems, Tineke P.; Prakken, Niek H. J.; Oudkerk, Matthijs; Sijens, Paul E.

    Reproducibility of myocardial contour determination in cardiac magnetic resonance imaging is important, especially when determining T2* values per myocardial segment as a prognostic factor of heart failure or thalassemia. A method creating a composite image with contrasts optimized for drawing

  10. Anatomical and functional volume concordance between FDG PET, and T2 and diffusion-weighted MRI for cervical cancer: a hybrid PET/MR study.

    Science.gov (United States)

    Sun, Hongzan; Xin, Jun; Zhang, Shaomin; Guo, Qiyong; Lu, Yueyue; Zhai, Wei; Zhao, Long; Peng, Weiai; Wang, Baijun

    2014-05-01

    To evaluate the concordance among (18)F-FDG PET imaging, MR T2-weighted (T2-W) imaging and apparent diffusion coefficient (ADC) maps with diffusion-weighted (DW) imaging in cervical cancer using hybrid whole-body PET/MR. This study prospectively included 35 patients with cervical cancer who underwent pretreatment (18)F-FDG PET/MR imaging. (18)F-FDG PET and MR images were fused using standard software. The percent of the maximum standardized uptake values (SUV max) was used to contour tumours on PET images, and volumes were calculated automatically. Tumour volumes measured on T2-W and DW images were calculated with standard techniques of tumour area multiplied by the slice profile. Parametric statistics were used for data analysis. FDG PET tumour volumes calculated using SUV max (14.30 ± 4.70) and T2-W imaging volume (33.81 ± 27.32 cm(3)) were similar (P > 0.05) at 35 % and 40 % of SUV max (32.91 ± 18.90 cm(3) and 27.56 ± 17.19 cm(3) respectively) and significantly correlated (P W imaging volumes (P > 0.05). PET subvolumes with increasing SUV max cut-off percentage showed an inverse change in mean ADC values on DW imaging (P W and DW imaging in cervical cancer. Cut-off at 35 % or 40 % of SUV max is recommended for (18)F-FDG PET/MR SUV-based tumour volume estimation. The linear tumour subvolume concordance between FDG PET and DW imaging demonstrates individual regional concordance of metabolic activity and cell density.

  11. Anatomical and functional volume concordance between FDG PET, and T2 and diffusion-weighted MRI for cervical cancer: a hybrid PET/MR study

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Hongzan; Xin, Jun; Zhang, Shaomin; Guo, Qiyong; Lu, Yueyue; Zhai, Wei; Zhao, Long [Shengjing Hospital of China Medical University, Department of Radiology, Shenyang, Liaoning (China); Peng, Weiai [NM Marketing, Great China, Philips Healthcare, Guangzhou (China); Wang, Baijun [Philips China Investment Co. Ltd. Shenyang Office, Shenyang, Liaoning (China)

    2014-05-15

    To evaluate the concordance among {sup 18}F-FDG PET imaging, MR T2-weighted (T2-W) imaging and apparent diffusion coefficient (ADC) maps with diffusion-weighted (DW) imaging in cervical cancer using hybrid whole-body PET/MR. This study prospectively included 35 patients with cervical cancer who underwent pretreatment {sup 18}F-FDG PET/MR imaging. {sup 18}F-FDG PET and MR images were fused using standard software. The percent of the maximum standardized uptake values (SUV{sub max}) was used to contour tumours on PET images, and volumes were calculated automatically. Tumour volumes measured on T2-W and DW images were calculated with standard techniques of tumour area multiplied by the slice profile. Parametric statistics were used for data analysis. FDG PET tumour volumes calculated using SUV{sub max} (14.30 ± 4.70) and T2-W imaging volume (33.81 ± 27.32 cm{sup 3}) were similar (P > 0.05) at 35 % and 40 % of SUV{sub max} (32.91 ± 18.90 cm{sup 3} and 27.56 ± 17.19 cm{sup 3} respectively) and significantly correlated (P < 0.001; r = 0.735 and 0.766). The mean DW volume was 30.48 ± 22.41 cm{sup 3}. DW volumes were not significantly different from FDG PET volumes at either 35 % SUV{sub max} or 40 % SUV{sub max} or from T2-W imaging volumes (P > 0.05). PET subvolumes with increasing SUV{sub max} cut-off percentage showed an inverse change in mean ADC values on DW imaging (P < 0.001, ANOVA). Hybrid PET/MR showed strong volume concordance between FDG PET, and T2-W and DW imaging in cervical cancer. Cut-off at 35 % or 40 % of SUV{sub max} is recommended for {sup 18}F-FDG PET/MR SUV-based tumour volume estimation. The linear tumour subvolume concordance between FDG PET and DW imaging demonstrates individual regional concordance of metabolic activity and cell density. (orig.)

  12. Magnetic resonance T2 relaxation time at 7 Tesla associated with amyloid β pathology and age in a double-transgenic mouse model of Alzheimer's disease.

    Science.gov (United States)

    Li, Lang; Wang, Xiao-Yi; Gao, Fa-Bao; Wang, Lei; Xia, Rui; Li, Zhi-Xiao; Xing, Wu; Tang, Bei-Sha; Zeng, Yi; Zhou, Gao-Feng; Zhou, Hai-Yan; Liao, Wei-Hua

    2016-01-01

    The aim of this study was to better understand the effect of amyloid-β plaques on magnetic resonance T2 relaxation time. We investigated these changes associated with age in an APP/PS1 mouse model of AD at 7 Tesla, combined with histology. Ten double-transgenic AD and ten wild type (WT) female mice (aged 12-20 months) were used in a cross-sectional study. Mean T2 values and standard deviations were calculated for each Regions of interest (ROIs) on T2 map. Immunohistochemistry for amyloid plaques and fluorescence staining with thioflavine S were performed of brain sections after imaging. The results showed that mean T2 values of the hippocampus, cortex, corpus callosum, and thalamus of older mice were significantly lower than of the younger. Compared to WT mice, the T2 values of the hippocampus, corpus callosum, and thalamus in younger AD mice were significantly greater, while the T2 values of the hippocampus and cortex in older AD mice were significantly less. Aβ-40 immunohistochemistry and thioflavine S stainging were positive in the matched region both for younger and older AD mice, while neither Aβ-40 nor thioflavine S were observed in WT mice. These findings suggest that regional T2 values of AD mice may decrease with age, and changes in T2 values in AD mice may be influenced by many factors besides amyloid-β plaque accumulation. Furthermore, they support that the standard deviation of the mean T2 value should be considered as well as the mean. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. Focal Treatment or Observation of Prostate Cancer: Pretreatment Accuracy of TRUS Biopsy and T2-Weighted MRI

    Science.gov (United States)

    Nogueira, Lucas; Wang, Liang; Fine, Samson W.; Pinochet, Rodrigo; Kurta, Jordan M.; Katz, Darren; Savage, Caroline J.; Cronin, Angel M.; Hricak, Hedvig; Scardino, Peter T.; Akin, Oguz; Coleman, Jonathan A.

    2013-01-01

    Objectives Focal treatment is a curative option for localized prostate cancer (PCA), but appropriate selection of patients hasn’t been established. We analyzed patients who had undergone radical prostatectomy (RP), with preoperative disease features considered favorable for focal treatment, to test the hypothesis that they would be accurately characterized with transrectal biopsy and prostate MRI. Methods 202 patients with PCA who had preoperative MRI and low-risk biopsy criteria (no Gleason grade 4/5, one involved core, < 2 mm, PSA density ≤ 0.10, clinical stage ≤ T2a). Indolent RP pathology was defined as no Gleason 4/5, organ confined, tumor volume < 0.5cc, negative surgical margins. MRI ability to locate and determine the tumor extent was assessed. Results After RP, 101 men (50%) had non-indolent cancer. Multifocal and bilateral tumors were present in 81% and 68% of patients, respectively. MRI indicated extensive disease in 16 (8%). MRI sensitivity to locate PCA ranged from 2–20%, and specificity from 91–95%. On univariate analysis, MRI evidence of extracapsular extension (ECE) (P = 0.027) and extensive disease (P = 0.001) were associated with non-indolent cancer. On multivariate analysis, only the later remained as significant predictor (P = 0.0018). Conclusions Transrectal biopsy identified men with indolent tumors favorable for focal treatment in 50% of cases. MRI findings of ECE and extensive tumor involving more than half of the gland are associated with unfavorable features, and may be useful excluding patients from focal treatment. According to these data, endorectal MRI isn’t sufficient to localize small tumors for focal treatment. PMID:19643467

  14. 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

  15. Confidence in Assessment of Lumbar Spondylolysis Using Three-Dimensional Volumetric T2-Weighted MRI Compared With Limited Field of View, Decreased-Dose CT.

    Science.gov (United States)

    Delavan, Joshua Adam; Stence, Nicholas V; Mirsky, David M; Gralla, Jane; Fadell, Michael F

    2016-07-01

    spondylolysis, 2D MRI is still very good at detecting spondylolysis while remaining sensitive for detection of alternative diagnoses such as disc abnormalities and pars stress reaction. The data suggest that standard 2D MRI sequences should not be entirely replaced by a volumetric T2-weighted 3D sequence (despite promising features of rapid acquisition time, increased spatial resolution, and reconstruction capability). © 2016 The Author(s).

  16. 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.

  17. MRI of the normal brain from early childhood to middle age. Pt. 1. Appearances on T2- and proton density-weighted images and occurrence of incidental high-signal foci

    International Nuclear Information System (INIS)

    Autti, T.; Raininko, R.; Vanhanen, S.L.; Kallio, M.; Santavuori, P.

    1994-01-01

    The magnetic resonance images of 67 healthy subjects aged 4-50 years were studied for differences in general signal intensity between the different brain structures, the frequency of focal intensity changes in the brain, and variations in size of the cerebrospinal fluid (CSF) spaces. In adults over 25 years of age the thalamus gave lower signal than the putamen or caudate nucleus. Definite periventricular high signal was found in the white matter of one third of subjects of all ages. Small (< 5 mm in diameter) high signal foci were found in the cerebral white matter on T2-weighted images in 27 % of subjects (20 % of healthy children and adolescents and 34 % of adults). They gave high signal on both short and long echoes in 11 % of children and adolescents and in 22 % of adults; 51 % of all foci gave high signal with both echoes. This does not support the hypothesis that they are caused mainly by enlarged Virchow-Robin spaces. Of the high signal foci on T2-weighted images, 86 % were in watershead areas. Two foci were found in one subject in the periventricular watershed area (beside the tips of the frontal horns) and they were never seen in the other deep white matter regions. In healthy, relatively young subjects with no known risk factors, high signal foci other than Virchow-Robin spaces, were common; neither their prevalence nor their number correlated with age in this series. A few slightly large sulci were found in some adults. (orig.)

  18. Hepatic lesions: improved image quality and detection with the periodically rotated overlapping parallel lines with enhanced reconstruction technique--evaluation of SPIO-enhanced T2-weighted MR images.

    Science.gov (United States)

    Hirokawa, Yuusuke; Isoda, Hiroyoshi; Maetani, Yoji S; Arizono, Shigeki; Shimada, Kotaro; Okada, Tomohisa; Shibata, Toshiya; Togashi, Kaori

    2009-05-01

    To evaluate the effectiveness of the periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) technique for superparamagnetic iron oxide (SPIO)-enhanced T2-weighted magnetic resonance (MR) imaging with respiratory compensation with the prospective acquisition correction (PACE) technique in the detection of hepatic lesions. The institutional human research committee approved this prospective study, and all patients provided written informed consent. Eighty-one patients (mean age, 58 years) underwent hepatic 1.5-T MR imaging. Fat-saturated T2-weighted turbo spin-echo images were acquired with the PACE technique and with and without the PROPELLER method after administration of SPIO. Images were qualitatively evaluated for image artifacts, depiction of liver edge and intrahepatic vessels, overall image quality, and presence of lesions. Three radiologists independently assessed these characteristics with a five-point confidence scale. Diagnostic performance was assessed with receiver operating characteristic (ROC) curve analysis. Quantitative analysis was conducted by measuring the liver signal-to-noise ratio (SNR) and the lesion-to-liver contrast-to-noise ratio (CNR). The Wilcoxon signed rank test and two-tailed Student t test were used, and P techniques resulted in significantly improved image quality, higher sensitivity, and greater area under the ROC curve for hepatic lesion detection than did MR imaging with the PACE technique alone (P technique than without it (P technique and SPIO enhancement is a promising method with which to improve the detection of hepatic lesions. (c) RSNA, 2009.

  19. Liver T2-weighted MR imaging: assessment of a three-dimensional fast spin-echo with extended echo train acquisition sequence at 1.5 Tesla.

    Science.gov (United States)

    Denoiseux, Céline Cotereau; Boulay-Coletta, Isabelle; Nakache, Jean-Pierre; Claude, Isabelle Dufour; Zins, Marc

    2013-08-01

    To retrospectively compare image quality and lesion detectability with two T2-weighted sequences at 1.5 Tesla (T): respiratory-triggered three-dimensional fat sat fast-spin-echo with extended echo-train acquisition (3D FSE-XETA) and respiratory-triggered two-dimensional fat-sat fast recovery fast-spin-echo (2D FRFSE). MR was performed at 1.5T in 53 consecutive patients. Two radiologists blinded to the sequence details reviewed the studies to determine: (i) signal and contrast to noise ratios, (ii) overall image quality, (iii) sensitivity for focal lesion detection. Image assessment scores for the 2D FRFSE sequence were significantly higher than those for the 3D FSE-XETA sequence for overall image quality (P < 0.01) and artifacts (P < 0.001). Sensitivity for liver lesion detection was higher with the 3D FSE-XETA sequence (69.3% versus 57.3%; P < 0.05) compared with the 2D FRFSE sequence. The 3D FSE-XETA sequence improves the reader confidence score (P < 0.01) for liver lesions detection. Inter-observer correlation was higher with the 3D FSE-XETA sequence. For T2-weighted liver imaging at 1.5T, the 3D FSE-XETA sequence improves sensitivity, reader confidence score and interobserver correlation for focal liver lesion detection, but it suffers from a lower overall image quality and higher artifacts. Copyright © 2013 Wiley Periodicals, Inc.

  20. 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.)

  1. T2 Magnetic Resonance Assay-Based Direct Detection of Three Lyme Disease-Related Borrelia Species in Whole-Blood Samples.

    Science.gov (United States)

    Snyder, Jessica L; Giese, Heidi; Bandoski-Gralinski, Cheryl; Townsend, Jessica; Jacobson, Beck E; Shivers, Robert; Schotthoefer, Anna M; Fritsche, Thomas R; Green, Clayton; Callister, Steven M; Branda, John A; Lowery, Thomas J

    2017-08-01

    In early Lyme disease (LD), serologic testing is insensitive and seroreactivity may reflect active or past infection. In this study, we evaluated a novel assay for the direct detection of three species of Borrelia spirochetes in whole blood. The T2 magnetic resonance (T2MR) assay platform was used to amplify Borrelia DNA released from intact spirochetes and to detect amplicon. Analytical sensitivity was determined from blood spiked with known concentrations of spirochetes, and the assay's limit of detection was found to be in the single-cell-per-milliliter range: 5 cells/ml for B. afzelii and 8 cells/ml for Borrelia burgdorferi and Borrelia garinii Clinical samples ( n = 66) from confirmed or suspected early LD patients were also analyzed. B. burgdorferi was detected using T2MR in 2/2 (100%) of blood samples from patients with confirmed early LD, based on the presence of erythema migrans and documentation of seroconversion or a positive real-time blood PCR. T2MR detected B. burgdorferi in blood samples from 17/54 (31%) of patients with probable LD, based on the presence of erythema migrans without documented seroconversion or of documented seroconversion in patients with a compatible clinical syndrome but without erythema migrans. Out of 21 clinical samples tested by real-time PCR, only 1 was positive and 13 were negative with agreement with T2MR. An additional 7 samples that were negative by real-time PCR were positive with T2MR. Therefore, T2MR enables a low limit of detection (LoD) for Borrelia spp. in whole blood samples and is able to detect B. burgdorferi in clinical samples. Copyright © 2017 American Society for Microbiology.

  2. Different patterns of myocardial iron distribution by whole-heart T2* magnetic resonance as risk markers for heart complications in thalassemia major.

    Science.gov (United States)

    Meloni, Antonella; Restaino, Gennaro; Borsellino, Zelia; Caruso, Vincenzo; Spasiano, Anna; Zuccarelli, Angelo; Valeri, Gianluca; Toia, Patrizia; Salvatori, Cristina; Positano, Vincenzo; Midiri, Massimo; Pepe, Alessia

    2014-12-20

    The multislice multiecho T2* cardiovascular magnetic resonance (CMR) technique allows to detect different patterns of myocardial iron overload (MIO). The aim of this cross-sectional study was to verify the association between cardiac complications (heart failure and arrhythmias), biventricular dysfunction and myocardial fibrosis with different patterns of MIO in thalassemia major (TM) patients. We considered 812 TM patients enrolled in the Myocardial Iron Overload in Thalassemia (MIOT) Network. The T2* value in all the 16 cardiac segments was evaluated. We identified 4 groups of patients: 138 with homogeneous MIO (all segments with T2* heart iron (global heart T2* heart iron, and 339 with no MIO (all segments with T2* ≥ 20 ms). Compared to patients with no MIO, patients with homogeneous MIO were more likely to have cardiac complications (odds ratio-OR = 2.67), heart failure (OR = 2.54), LV dysfunction (OR = 5.59), and RV dysfunction (OR = 2.26); patients with heterogeneous MIO and significant global heart iron were more likely to have heart failure (OR = 2.38) and LV dysfunction (OR = 2.39). Cardiac complications, heart failure and dysfunction were correlated with MIO distribution with an increasing risk from the TM patients with no MIO to those with homogeneous MIO. Using a segmental approach, early iron deposit or homogeneous MIO patterns can be characterized to better tailor chelation therapy. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. Diagnostic performance and reproducibility of T2w based and diffusion weighted imaging (DWI) based PI-RADSv2 lexicon descriptors for prostate MRI.

    Science.gov (United States)

    Benndorf, Matthias; Hahn, Felix; Krönig, Malte; Jilg, Cordula Annette; Krauss, Tobias; Langer, Mathias; Dovi-Akué, Philippe

    2017-08-01

    To examine the diagnostic performance of PI-RADSv2 T2w and diffusion weighted imaging (DWI) based lexicon descriptors, inter-observer agreement for descriptor assignment and diagnostic accuracy of the PI-RADSv2 assessment categories for multiparametric prostate MRI. 176 lesions in 79 consecutive patients are analyzed, lesions are histopathologically verified by MRI-ultrasound fusion biopsy. All lesions are rated according to the PI-RADSv2 lexicon, descriptors for T2w and DWI sequences and resulting assessment categories are assigned by two independent blinded radiologists. We perform receiver-operating-characteristic analysis using the assessment categories. To analyze inter-observer agreement, we calculate weighted kappa values for assessment category assignment and unweighted kappa values for descriptor assignment. PI-RADSv2 assessment categories yield an area under the curve of 0.76/0.74 (radiologist 1/radiologist 2), P >0.05. Weighted kappa for agreement is 0.601 in the peripheral zone and 0.580 in the transition zone. We detect a difference in the cancer rate for PI-RADSv2 category 3 between peripheral zone (32%) and transition zone (12%), P PI-RADSv2 lexicon is at most moderate in our study. Typical descriptors for benign and malignant lesions are validated, whereas the discriminatory power of some descriptors is challenged. The difference in the cancer rate for PI-RADSv2 category 3 between peripheral zone and transition zone should be considered when management recommendations are linked to assessment categories in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Image Diagnostic Classification of Magnetic Resonance T2 Increased Signal Intensity in Cervical Spondylotic Myelopathy: Clinical Evaluation Using Quantitative and Objective Assessment.

    Science.gov (United States)

    Machino, Masaaki; Imagama, Shiro; Ando, Kei; Kobayashi, Kazuyoshi; Ito, Kenyu; Tsushima, Mikito; Matsumoto, Akiyuki; Morozumi, Masayoshi; Tanaka, Satoshi; Ito, Keigo; Kato, Fumihiko; Nishida, Yoshihiro; Ishiguro, Naoki

    2018-03-15

    A prospective imaging study. The study investigated whether the classification of increased signal intensity (ISI) using magnetic resonance imaging (MRI) reflects the severity of symptoms in patients with cervical spondylotic myelopathy (CSM). Although the ISI on MRI in patients with CSM is observed, the degree of ISI has not been examined. The association between ISI and the surgical outcomes in cervical myelopathy remains controversial. A total of 505 consecutive patients with CSM (311 males; 194 females) were enrolled. The mean age was 66.6 years (range, 41-91 yrs), with an average postoperative follow-up period of 26.5 ± 12.5 months. The ISI was classified into three groups based on sagittal T2-weighted MRI as follows: Grade 0, none; Grade 1, light (obscure); and Grade 2, intense (bright). Pre- and postoperative neurological status was evaluated using the Japanese Orthopedic Association scoring system for cervical myelopathy (JOA score) and quantifiable tests, including the 10-s grip and release test (10-s G&R test) and the 10-s step test. The preoperative MRI showed 168 patients in Grade 0, 169 patients in Grade 1, and 168 in Grade 2, with no age differences among three groups. Grade 2 patients had a longer duration of symptom compared with the other grades. Grade 0 patients had a better postoperative JOA score and recovery rate compared with the other grades. The preoperative and postoperative scores in the G&R test and steps were better in the Grade 0 patients compared with the other grades. Grade 1 and 2 patients had similar outcomes and recovery rates. ISI on MRI in patients with CSM was prospectively classified into three grades. The ISI grading was not associated with the preoperative severity of myelopathy and outcomes. 2.

  5. Boosting the SNR by adding a receive-only endorectal monopole to an external antenna array for high-resolution, T2-weighted imaging of early-stage cervical cancer with 7-T MRI.

    Science.gov (United States)

    van Kalleveen, I M L; Hoogendam, J P; Raaijmakers, A J E; Visser, F; Arteaga de Castro, C S; Verheijen, R H M; Luijten, P R; Zweemer, R P; Veldhuis, W B; Klomp, D W J

    2017-09-01

    The aim of this study was to investigate the signal-to-noise ratio (SNR) gain in early-stage cervical cancer at ultrahigh-field MRI (e.g. 7 T) using a combination of multiple external antennas and a single endorectal antenna. In particular, we used an endorectal monopole antenna to increase the SNR in cervical magnetic resonance imaging (MRI). This should allow high-resolution, T 2 -weighted imaging and magnetic resonance spectroscopy (MRS) for metabolic staging, which could facilitate the local tumor status assessment. In a prospective feasibility study, five healthy female volunteers and six patients with histologically proven stage IB1-IIB cervical cancer were scanned at 7 T. We used seven external fractionated dipole antennas for transmit-receive (transceive) and an endorectally placed monopole antenna for reception only. A region of interest, containing both normal cervix and tumor tissue, was selected for the SNR measurement. Separated signal and noise measurements were obtained in the region of the cervix for each element and in the near field of the monopole antenna (radius antenna in each patient. We obtained high-resolution, T 2 -weighted images with a voxel size of 0.7 × 0.8 × 3.0 mm 3 . In four cases with optimal placement of the endorectal antenna (verified on the T 2 -weighted images), a mean gain of 2.2 in SNR was obtained at the overall cervix and tumor tissue area. Within a radius of 30 mm from the monopole antenna, a mean SNR gain of 3.7 was achieved in the four optimal cases. Overlap between the two different regions of the SNR calculations was around 24%. We have demonstrated that the use of an endorectal monopole antenna substantially increases the SNR of 7-T MRI at the cervical anatomy. Combined with the intrinsically high SNR of ultrahigh-field MRI, this gain may be employed to obtain metabolic information using MRS and to enhance spatial resolutions to assess tumor invasion. Copyright © 2017 John Wiley & Sons, Ltd.

  6. 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.

  7. High-resolution T2-weighted MR imaging of the inner ear using a long echo-train-length 3D fast spin-echo sequence

    International Nuclear Information System (INIS)

    Naganawa, S.; Yamakawa, K.; Fukatsu, H.; Ishigaki, T.; Nakashima, T.; Sugimoto, H.; Aoki, I.; Miyazaki, M.; Takai, H.

    1996-01-01

    The purpose of this study was to assess the value of a long echo-train-length 3D fast spin-echo (3D-FSE) sequence in visualizing the inner ear structures. Ten normal ears and 50 patient ears were imaged on a 1.5T MR unit using a head coil. Axial high-resolution T2-weighted images of the inner ear and the internal auditory canal (IAC) were obtained in 15 min. In normal ears the reliability of the visualization for the inner ear structures was evaluated on original images and the targeted maximum intensity projection (MIP) images of the labyrinth. In ten normal ears, 3D surface display (3D) images were also created and compared with MIP images. On the original images the cochlear aqueduct, the vessels in the vicinity of the IAC, and more than three branches of the cranial nerves were visualized in the IAC in all the ears. The visibility of the endolympathic duct was 80%. On the MIP images the visibility of the three semicircular canals, anterior and posterior ampulla, and of more than two turns of the cochlea was 100%. The MIP images and 3D images were almost comparable. The visibility of the endolymphatic duct was 80% in normal ears and 0% in the affected ears of the patients with Meniere's disease (p<0.001). In one patient ear a small intracanalicular tumor was depicted clearly. In conclusion, the long echo train length T2-weighted 3D-FSE sequence enables the detailed visualization of the tiny structures of the inner ear and the IAC within a clinically acceptable scan time. Furthermore, obtaining a high contrast between the soft/bony tissue and the cerebrospinal/endolymph/perilymph fluid would be of significant value in the diagnosis of the pathologic conditions around the labyrinth and the IAC. (orig.)

  8. Multi-contrast brain magnetic resonance image super-resolution using the local weight similarity.

    Science.gov (United States)

    Zheng, Hong; Qu, Xiaobo; Bai, Zhengjian; Liu, Yunsong; Guo, Di; Dong, Jiyang; Peng, Xi; Chen, Zhong

    2017-01-17

    Low-resolution images may be acquired in magnetic resonance imaging (MRI) due to limited data acquisition time or other physical constraints, and their resolutions can be improved with super-resolution methods. Since MRI can offer images of an object with different contrasts, e.g., T1-weighted or T2-weighted, the shared information between inter-contrast images can be used to benefit super-resolution. In this study, an MRI image super-resolution approach to enhance in-plane resolution is proposed by exploring the statistical information estimated from another contrast MRI image that shares similar anatomical structures. We assume some edge structures are shown both in T1-weighted and T2-weighted MRI brain images acquired of the same subject, and the proposed approach aims to recover such kind of structures to generate a high-resolution image from its low-resolution counterpart. The statistical information produces a local weight of image that are found to be nearly invariant to the image contrast and thus this weight can be used to transfer the shared information from one contrast to another. We analyze this property with comprehensive mathematics as well as numerical experiments. Experimental results demonstrate that the image quality of low-resolution images can be remarkably improved with the proposed method if this weight is borrowed from a high resolution image with another contrast. Multi-contrast MRI Image Super-resolution with Contrast-invariant Regression Weights.

  9. 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.

  10. 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.)

  11. 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)

  12. 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)

  13. Anisotropic dependence of the magnetic transition on uniaxial pressure in the Kondo semiconductors Ce T2A l10 (T =Ru and Os)

    Science.gov (United States)

    Hayashi, K.; Umeo, K.; Takeuchi, T.; Kawabata, J.; Muro, Y.; Takabatake, T.

    2017-12-01

    We have measured the strain, magnetization, and specific heat of the antiferromagnetic (AFM) Kondo semiconductors Ce T2A l10 (T =Ru and Os) under uniaxial pressures applied along the orthorhombic axes. We found a linear dependence of TN on the b -axis parameter for both compounds under uniaxial pressure P ∥b and hydrostatic pressure. This relation indicates that the distance between the Ce-T layers along the b axis is the key structural parameter determining TN. Furthermore, the pressure dependence of the spin-flop transition field indicates that Ce-Ce interchain interactions stabilize the AFM state with the ordered moments pointing to the c axis.

  14. Studies on the response of resistive-wall modes to applied magnetic perturbations in the EXTRAP T2R reversed field pinch

    Science.gov (United States)

    Gregoratto, D.; Drake, J. R.; Yadikin, D.; Liu, Y. Q.; Paccagnella, R.; Brunsell, P. R.; Bolzonella, T.; Marchiori, G.; Cecconello, M.

    2005-09-01

    Arrays of magnetic coils and sensors in the EXTRAP T2R [P. R. Brunsell et al., Plasma Phys. Controlled Fusion 43 1457 (2001)] reversed-field pinch have been used to investigate the plasma response to an applied resonant magnetic perturbation in the range of the resistive-wall modes (RWMs). Measured RWM growth rates agree with predictions of a cylindrical ideal-plasma model. The linear growth of low-n marginally stable RWMs is related to the so-called resonant-field amplification due to a dominant ∣n∣=2 machine error field of about 2 G. The dynamics of the m =1 RWMs interacting with the applied field produced by the coils can be accurately described by a two-pole system. Estimated poles and residues are given with sufficient accuracy by the cylindrical model with a thin continuous wall.

  15. In vivo assessment of iron content of the cerebral cortex in healthy aging using 7-Tesla T2*-weighted phase imaging.

    Science.gov (United States)

    Buijs, Mathijs; Doan, Nhat Trung; van Rooden, Sanneke; Versluis, Maarten J; van Lew, Baldur; Milles, Julien; van der Grond, Jeroen; van Buchem, Mark A

    2017-05-01

    Accumulation of brain iron has been suggested as a biomarker of neurodegeneration. Increased iron has been seen in the cerebral cortex in postmortem studies of neurodegenerative diseases and healthy aging. Until recently, the diminutive thickness of the cortex and its relatively low iron content have hampered in vivo study of cortical iron accumulation. Using phase images of a T2*-weighted sequence at ultrahigh field strength (7 Tesla), we examined the iron content of 22 cortical regions in 70 healthy subjects aged 22-80 years. The cortex was automatically segmented and parcellated, and phase shift was analyzed using an in-house developed method. We found a significant increase in phase shift with age in 20 of 22 cortical regions, concurrent with current understanding of cortical iron accumulation. Our findings suggest that increased cortical iron content can be assessed in healthy aging in vivo. The high spatial resolution and sensitivity to iron of our method make it a potentially useful tool for studying cortical iron accumulation in healthy aging and neurodegenerative diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Derivation of a T2-weighted MRI total colonic inflammation score (TCIS) for assessment of patients with severe acute inflammatory colitis - a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Hafeez, Rehana; Boulos, Paul [University College London Hospitals NHS Trust, Department of Surgery, London (United Kingdom); Punwani, Shonit; Halligan, Steve [University College London, Centre for Medical Imaging, London (United Kingdom); University College London Hospitals NHS Trust, Department of Specialist X-ray, Level 2 podium, London (United Kingdom); Pendse, Doug [University College London, Centre for Medical Imaging, London (United Kingdom); Bloom, Stuart [University College London Hospitals NHS Trust, Department of Gastroenterology, London (United Kingdom); Taylor, Stuart A. [University College London, Centre for Medical Imaging, London (United Kingdom); University College London Hospitals NHS Trust, Department of Specialist X-ray, Level 2 podium, London (United Kingdom)

    2011-02-15

    To derive an MRI score for assessing severity, therapeutic response and prognosis in acute severe inflammatory colitis. Twenty-one patients with acute severe colitis underwent colonic MRI after admission and again (n = 16) after median 5 days of treatment. Using T2-weighted images, two radiologists in consensus graded segmental haustral loss, mesenteric and mural oedema, mural thickness, and small bowel and colonic dilatation producing a total colonic inflammatory score (TCIS, range 6-95). Pre- and post-treatment TCIS were compared, and correlated with CRP, stool frequency, and number of inpatient days (therapeutic response marker). Questionnaire assessment of patient worry, satisfaction and discomfort graded 1 (bad) to 7 (good) was administered Admission TCIS correlated significantly with CRP (Kendall's tau=0.45, 95% confidence interval [CI] 0.11-0.79, p = 0.006), and stool frequency (Kendall's tau 0.39, 95% CI 0.14-0.64, p = 0.02). TCIS fell after treatment (median [22 range 15-31]) to median 20 [range 8-25], p = 0.01. Admission TCIS but not CRP or stool frequency was correlated with length of inpatient stay (Kendall's tau 0.40, 95% CI 0.11-0.69, p = 0.02). Patients reported some discomfort (median score 4) during MRI. MRI TCIS falls after therapy, correlates with existing markers of disease severity, and in comparison may better predict therapeutic response. (orig.)

  17. T2*-weighted MR angiography substantially increases the detection of hemorrhage in the wall of brain abscess: implications in clinical interpretation

    International Nuclear Information System (INIS)

    Gupta, Rakesh Kumar; Tomar, Vaishali; Awasthi, Rishi; Yadav, Abhishek; Husain, Nuzhat; Bharadwaj, Vikas; Ojha, Bal K.; Behari, Sanjay; Prasad, Kashi N.; Singh Rathore, Ram Kishore

    2012-01-01

    The purpose of the present study was to identify the true prevalence of hemorrhage in the abscess using T2*-weighted angiography (SWAN) imaging and to study its influence on diffusion tensor imaging (DTI) metrics. Fifteen patients of brain abscess underwent conventional, SWAN, and DT imaging on a 3-T MRI followed by its confirmation with histology. DTI metrics were quantified by region-of-interest analysis on hemorrhagic and non-hemorrhagic regions of the abscess wall. Prussian blue staining was performed on excised abscess walls to confirm hemorrhage on histology. Eleven of 15 patients showed evidence of hemorrhage on both Prussian blue staining as well as SWAN imaging. Fractional anisotropy (FA) and linear anisotropy (CL) values were significantly higher, while spherical anisotropy was significantly lower in hemorrhagic compared to non-hemorrhagic regions of the abscess wall. Hemorrhage in the abscess wall is a common feature and may not always indicate neoplasm. The presence of intracellular iron in addition to concentrically laid collagen fibers may have synergistic effect on FA and CL values in the abscess wall. Inclusion of SWAN to MRI protocol will define the true prevalence of hemorrhage in brain abscess. (orig.)

  18. Hematoma size in deep intracerebral hemorrhage and its correlation with dot-like hemosiderin spots on gradient echo T2*-weighted MRI.

    Science.gov (United States)

    Imaizumi, Toshio; Honma, Toshimi; Horita, Yoshifumi; Kohama, Ikuhide; Miyata, Kei; Kawamura, Maiko; Niwa, Jun

    2006-07-01

    Dot-like low intensity spots (dot-like hemosiderin spots: dotHSs) on gradient echo T2*-weighted MRI have been histologically diagnosed to represent old cerebral microbleeds associated with microangiopathies. They have also been correlated to the fragility of small vessels and the tendency to bleed. Therefore, a substantial number of dotHSs might be associated with a large-sized, deep intracerebral hematoma (ICH). On the other hand, dotHSs may reflect old microbleeds that did not enlarge to symptomatic size. To investigate how dotHSs are related to the size (maximal diameter) of primary deep ICH, we analyzed the diameter and the number of dotHSs in 151 patients with deep ICH not associated with subarachnoid hemorrhage or intraventricular hemorrhage (75 males and 76 females, age ranged from 37 to 90 [65.7 +/- 11.3 years old] who were consecutively admitted to Hakodate Municipal Hospital. The hazard ratio (HR) for a maximal diameter of deep ICH or =2 cm (4.7 +/- 7.0, P= .012). Multivariate analysis revealed that a maximal diameter of deep ICH of < or =2 cm was found in patients with dotHS (HR, 3.7; 95% confidence interval [CI], 1.4-10.1; P= .009). Though small sample size limited the power of our analyses, these findings suggest that the number of dotHSs may be associated with a small diameter of deep ICH.

  19. In vivo proton magnetic resonance spectroscopy of liver metabolites in non-alcoholic fatty liver disease in rats: T2 relaxation times in methylene protons.

    Science.gov (United States)

    Song, Kyu-Ho; Baek, Hyeon-Man; Lee, Do-Wan; Choe, Bo-Young

    2015-10-01

    The aim of this study was to evaluate the transverse relaxation time of methylene resonance as compared to other lipid resonances. The examinations were performed using a 3.0 T scanner with a point-resolved spectroscopy (PRESS) sequence. Lipid relaxation time in a lipid phantom filled with canola oil was estimated with a repetition time (TR) of 6000ms and echo time (TE) of 40-550ms. For in vivo proton magnetic resonance spectroscopy ((1)H-MRS), eight male Sprague-Dawley rats were given free access to a normal-chow (NC) and another eight male Sprague-Dawley rats were given free access to a high-fat (HF) diet. Both groups drank water ad libitum. T2 measurements in the rats' livers were conducted at a fixed TR of 6000ms and TE of 40-220ms. Exponential curve fitting quality was calculated through the coefficients of determination (R(2)). Chemical analyses of the phantom and livers were not performed, but T2 decay curves were acquired. The T2 relaxation time of methylene resonance was estimated as follows: NC rats, 37.1±4.3ms; HF rats, 31.4±1.8ms (p<0.05). The extrapolated M0 values were higher in HF rats than in NC rats (p<0.005). This study of (1)H MRS led to sufficient spectral resolution and signal-to-noise ratio differences to characterize the T2 relaxation times of methylene resonance. (1)H MRS relaxation times may be useful for quantitative characterization of various liver diseases, including fatty liver disease. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Endorectal T2-weighted MRI does not differentiate between favorable and adverse pathologic features in men with prostate cancer who would qualify for active surveillance.

    Science.gov (United States)

    Guzzo, Thomas J; Resnick, Matthew J; Canter, Daniel J; Bivalacqua, Trinity J; Rosen, Mark A; Bergey, Meredith R; Magerfleisch, Laurie; Tomazewski, John E; Wein, Alan J; Malkowicz, S Bruce

    2012-01-01

    With the increased diagnosis of low grade, low volume, potentially non-lethal disease, active surveillance (AS) has become an increasingly popular alternative for select men with low-risk prostate cancer. The absence of precise clinical staging modalities currently makes it difficult to predict which patients are most appropriate for AS. The goal of our study was to evaluate the ability of endorectal MRI (eMRI) to predict adverse pathologic features in patients who would otherwise qualify for an AS program. We retrospectively reviewed our institution's radical prostatectomy (RP) database from 1991 to 2007 and identified 172 patients who would have qualified for AS and underwent preoperative staging eMRI with T2-weighted (T2W) sequences. MRI findings were correlated to final pathology in order to assess the ability of staging eMRI to predict adverse pathologic features in patients suitable for AS. The mean age of our cohort was 59.8 ± 6.2 years. The mean PSA at the time of diagnosis was 5.2 ± 2.2 ng/ml. In 51% of patients, no discrete tumor was visualized on eMRI and in 49% of patients a discrete tumor was detected. At the time of RP, Gleason score upgrading, extracapsular extension, and a positive surgical margin occurred in 17%, 6%, and 5% of cases, respectively. Patients with documented tumor on eMRI did not have an increased incidence of adverse pathologic findings with regard to tumor volume (P = 0.31), extra-capsular extension (P = 0.82), Gleason upgrading (P = 0.92), seminal vesicle invasion (P = 0.97), or positive surgical margin rate (P = 0.95) compared with those in whom no tumor was seen. Discrete tumor identification on eMRI is not predictive of adverse pathologic features in patients who would otherwise qualify for AS. eMRI likely does not provide additional information when prospectively evaluating patients for AS protocols. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Evaluation of Adhesive Capsulitis of the Shoulder With Fat-Suppressed T2-Weighted MRI: Association Between Clinical Features and MRI Findings.

    Science.gov (United States)

    Park, Sunghoon; Lee, Doo-Hyung; Yoon, Seung-Hyun; Lee, Hyun Young; Kwack, Kyu-Sung

    2016-07-01

    The purpose of this study was to examine the association between clinical features and MRI findings in adhesive capsulitis of the shoulder. This study included 103 patients (41 men, 62 women) with adhesive capsulitis. The MRI findings were correlated with pain intensity, range of motion, and clinical stage. Joint capsule edema in the axillary recess, extracapsular edema, obliteration of the subcoracoid fat triangle, and effusion in the long head biceps tendon sheath were assessed by two radiologists using fat-suppressed T2-weighted images. Joint capsule thickness in the axillary recess and degree of external rotation during MRI were also measured. Intraclass correlation coefficient and kappa values were obtained. Associations between MRI findings and clinical features were assessed by statistical analyses. Anterior extracapsular edema was associated with range of motion on external rotation and abduction (p capsule edema in the humeral portion of the axillary recess was associated with range of motion on external rotation (p = 0.01). Joint capsule thickness in the humeral portion of the axillary recess and height of the axillary recess were associated with pain intensity (p capsule edema in the humeral portion of the axillary recess and obliteration of the subcoracoid fat triangle were significantly more common in the early stages of adhesive capsulitis (p capsule thickness in the humeral portion of the axillary recess at stage 1 (4.67 ± 1.73 mm) was significantly different from the thickness at the later stages (stage 2, 3.73 ± 1.49 mm; stages 3 and 4, 3.67 ± 1.44 mm) (p adhesive capsulitis.

  2. Magnetic Resonance Image Texture Analysis of the Periaqueductal Gray Matter in Episodic Migraine Patients without T2-Visible Lesions

    Science.gov (United States)

    Chen, Zhiye; Chen, Xiaoyan; Liu, Mengqi; Liu, Shuangfeng; Yu, Shengyuan

    2018-01-01

    Objective The periaqueductal gray matter (PAG), a small midbrain structure, presents dysfunction in migraine. However, the precise neurological mechanism is still not well understood. Herein, the aim of this study was to investigate the texture characteristics of altered PAG in episodic migraine (EM) patients based on high resolution brain structural magnetic resonance (MR) images. Materials and Methods The brain structural MR images were obtained from 18 normal controls (NC), 18 EM patients and 16 chronic migraine (CM) patients using a 3T MR system. A PAG template was created using the International Consortium Brain Mapping 152 gray matter model, and the individual PAG segment was developed by applying the deformation field from the structural image segment to the PAG template. A grey level co-occurrence matrix was used to calculate the texture parameters including the angular second moment (ASM), contrast, correlation, inverse difference moment (IDM) and entropy. Results There was a significant difference for ASM, IDM and entropy in the EM group (998.629 ± 0.162 × 10−3, 999.311 ± 0.073 × 10−3, 916.354 ± 0.947 × 10−5) compared to that found in the NC group (998.760 ± 0.110 × 10−3, 999.358 ± 0.037 × 10−3 and 841.198 ± 0.575 × 10−5) (p < 0.05). The entropy was significantly lower among the patients with CM (864.116 ± 0.571 × 10−5) than that found among patients with EM (p < 0.05). The area under the receiver operating characteristic curve was 0.776 and 0.750 for ASM and entropy in the distinction of the EM from NC groups, respectively. ASM was negatively related to disease duration (DD) and the Migraine Disability Assessment Scale (MIDAS) scores in the EM group, and entropy was positively related to DD and MIDAS in the EM group (p < 0.05). Conclusion The present study identified altered MR image texture characteristics of the PAG in EM. The identified texture characteristics could be considered as imaging biomarkers for EM. PMID:29354004

  3. Fermi surface and effect of high magnetic fields on the metal-semimetal Peierls-like transition of (TSeT)2Cl

    International Nuclear Information System (INIS)

    Laukhin, V.; Audouard, Allan; Vignolles, David; Drigo, Lois; Alemany, Pere; Canadell, Enric

    2014-01-01

    Resistance measurements in pulsed magnetic fields up to 55 T as well as a first-principles DFT calculation of the Fermi surface for the organic metal (TSeT) 2 Cl have been performed to investigate its metal-semimetal phase transition. The results obtained are in line with the imperfect nesting that can be inferred from both the observed metallic behavior of the resistivity at low temperature and the previously reported Shubnikov-de Haas oscillations due to small carrier pockets. The DFT study points out the possibility that the LUMO bands of the TSeT donor may interact with the HOMO ones and modify the shape of the Fermi surface under pressure

  4. T2-weighted MR imaging of liver lesions: a prospective evaluation comparing turbo spin-echo, breath-hold turbo spin-echo and half-Fourier turbo spin-echo (HASTE) sequences

    International Nuclear Information System (INIS)

    Martin, J.; Villajos, M.; Oses, M. J.; Veintemillas, M.; Rue, M.; Puig, J.; Sentis, M.

    2000-01-01

    To compare turbo spin-echo (TSE), breath-hold TSE and half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences quantitatively and qualitatively in T2-weighted images of liver lesions. The authors evaluated prospectively 89 liver lesions in 73 patients using a 1.0-T magnetic resonance system to compare TSE, breath-hold TSE and HASTE sequences. The quantitative parameters were: lesion-to-liver contrast and lesion-to-liver contrast-to-noise ratio. The qualitative analysis was performed by two observers in consensus who examined four parameters: respiratory artifacts, lesion edge definition, intrahepatic vessel definition and image quality. Repeated measures analysis of variance was utilized to compare the quantitative variables and Friedman's nonparametric test for the qualitative parameters. In quantitative terms, the lesion-to-liver contrast was similar in TSE and breath-hold TSE sequences (2.45±1.44 versus 2.60±1.66), both of which were significantly better than the HASTE sequence (1.12±0.72; p<0.001). The lesion-to-liver contrast-to-noise ratio was significantly higher in the TSE sequence (62.60±46.40 versus 40.22±25.35 versus 50.90±32.10 for TSE, breath-hold TSE and HASTE sequences, respectively; p<0.001). In the qualitative comparisons, the HASTE sequence was significantly better than the TSE and breath-hold TSE sequences (p<0.001) in terms of artifacts and definition of lesion edge and intrahepatic vessels. Image quality was also significantly greater in the HASTE sequence (p<0.001). In quantitative terms, the TSE sequence is better than the breath-hold TSE and HASTE sequences, but there are no movement artifacts in the HASTE sequence, which is also significantly superior to TSE and breath-hold TSE sequences in qualitative terms and, thus, can be employed for T2-weighted images in liver studies. (Author) 17 refs

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

    International Nuclear Information System (INIS)

    Hakyemez, B.; Erdogan, C.; Yildirim, N.; Gokalp, G.; Parlak, M.

    2005-01-01

    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

  6. 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.

  7. Preparation and Characterization of Ferrofluid Stabilized with Biocompatible Chitosan and Dextran Sulfate Hybrid Biopolymer as a Potential Magnetic Resonance Imaging (MRI T2 Contrast Agent

    Directory of Open Access Journals (Sweden)

    Tzu-Chen Yen

    2012-10-01

    Full Text Available Chitosan is the deacetylated form of chitin and used in numerous applications. Because it is a good dispersant for metal and/or oxide nanoparticle synthesis, chitosan and its derivatives have been utilized as coating agents for magnetic nanoparticles synthesis, including superparamagnetic iron oxide nanoparticles (SPIONs. Herein, we demonstrate the water-soluble SPIONs encapsulated with a hybrid polymer composed of polyelectrolyte complexes (PECs from chitosan, the positively charged polymer, and dextran sulfate, the negatively charged polymer. The as-prepared hybrid ferrofluid, in which iron chloride salts (Fe3+ and Fe2+ were directly coprecipitated inside the hybrid polymeric matrices, was physic-chemically characterized. Its features include the z-average diameter of 114.3 nm, polydispersity index of 0.174, zeta potential of −41.5 mV and iron concentration of 8.44 mg Fe/mL. Moreover, based on the polymer chain persistence lengths, the anionic surface of the nanoparticles as well as the high R2/R1 ratio of 13.5, we depict the morphology of SPIONs as a cluster because chitosan chains are chemisorbed onto the anionic magnetite surfaces by tangling of the dextran sulfate. Finally, the cellular uptake and biocompatibility assays indicate that the hybrid polymer encapsulating the SPIONs exhibited great potential as a magnetic resonance imaging T2 contrast agent for cell tracking.

  8. Iron deposition in the gray matter in patients with relapse-remitting multiple sclerosis: A longitudinal study using three-dimensional (3D)-enhanced T2*-weighted angiography (ESWAN)

    Energy Technology Data Exchange (ETDEWEB)

    Du, Silin, E-mail: 182389558@qq.com; Sah, Shambhu K., E-mail: mrsks2007@hotmail.com; Zeng, Chun, E-mail: zengchun19840305@163.com; Wang, Jingjie, E-mail: 345151097@qq.com; Liu, Yi, E-mail: 993537544@qq.com; Xiong, Hua, E-mail: rjdfxyh@163.com; Li, Yongmei, E-mail: lymzhang70@aliyun.com

    2015-07-15

    Purpose: To investigate the relationship between the iron content by magnetic resonance imaging (MRI) and clinic correlation in patients with relapse-remitting multiple sclerosis (RRMS) over a two-year period. Methods: Thirty RRMS patients and 30 healthy control subjects were examined twice, two years apart, by undergoing brain conventional MRI and three-dimensional (3D)-enhanced T2*-weighted angiography (ESWAN) sequences at 3.0 T. Quantitative differences in iron content in deep gray matter (GM) nuclei and precentral gyrus GM between patients and control subjects with repeated-measures the mean phase values (MPVs) for ESWAN-filtered phase images. Spearman's rank correlation coefficient analysis was used to evaluate correlations of the MPVs, both 2-year-difference and single-time measurements, to disease duration, expanded disability status scale (EDSS) and times of recurrence. Results: The RRMS patients had higher GM iron concentration than that of the healthy control subjects in both single-time measurements, but only the substantia nigra (SN), and the precentral gyrus GM (PGM) showed a significant statistical difference (p < 0.05). Using the paired samples t test, we found that there were significant differences in two-year-difference measurements of the MPVs in the putamen (PUT), the globus pallidus (GP), the head of the caudate nucleus (HCN), the thalamus (THA), SN, the red nucleus (RN), the dentate nucleus (DN) and PGM, especially in SN (t = 2.92, p = 0.007) in RRMS patients. The MPVs of the PUT, GP, HCN, THA, SN, RN, DN and PGM for the subgroup with RRMS patients in times of recurrence less than twice were similar to the healthy controls. There was no significant difference in all regions of interests (ROIs). However, there were significant differences in all ROIs except THA and GP for the other subgroup with RRMS patients in times of recurrence more than and equal to twice. Spearman's rank correlation coefficient analysis showed there were

  9. Iron deposition in the gray matter in patients with relapse-remitting multiple sclerosis: A longitudinal study using three-dimensional (3D)-enhanced T2*-weighted angiography (ESWAN)

    International Nuclear Information System (INIS)

    Du, Silin; Sah, Shambhu K.; Zeng, Chun; Wang, Jingjie; Liu, Yi; Xiong, Hua; Li, Yongmei

    2015-01-01

    Purpose: To investigate the relationship between the iron content by magnetic resonance imaging (MRI) and clinic correlation in patients with relapse-remitting multiple sclerosis (RRMS) over a two-year period. Methods: Thirty RRMS patients and 30 healthy control subjects were examined twice, two years apart, by undergoing brain conventional MRI and three-dimensional (3D)-enhanced T2*-weighted angiography (ESWAN) sequences at 3.0 T. Quantitative differences in iron content in deep gray matter (GM) nuclei and precentral gyrus GM between patients and control subjects with repeated-measures the mean phase values (MPVs) for ESWAN-filtered phase images. Spearman's rank correlation coefficient analysis was used to evaluate correlations of the MPVs, both 2-year-difference and single-time measurements, to disease duration, expanded disability status scale (EDSS) and times of recurrence. Results: The RRMS patients had higher GM iron concentration than that of the healthy control subjects in both single-time measurements, but only the substantia nigra (SN), and the precentral gyrus GM (PGM) showed a significant statistical difference (p < 0.05). Using the paired samples t test, we found that there were significant differences in two-year-difference measurements of the MPVs in the putamen (PUT), the globus pallidus (GP), the head of the caudate nucleus (HCN), the thalamus (THA), SN, the red nucleus (RN), the dentate nucleus (DN) and PGM, especially in SN (t = 2.92, p = 0.007) in RRMS patients. The MPVs of the PUT, GP, HCN, THA, SN, RN, DN and PGM for the subgroup with RRMS patients in times of recurrence less than twice were similar to the healthy controls. There was no significant difference in all regions of interests (ROIs). However, there were significant differences in all ROIs except THA and GP for the other subgroup with RRMS patients in times of recurrence more than and equal to twice. Spearman's rank correlation coefficient analysis showed there were

  10. Prostate cancer evaluated with ferumoxtran-10-enhanced T2*-weighted MR Imaging at 1.5 and 3.0 T: early experience.

    NARCIS (Netherlands)

    Heesakkers, R.A.M.; Futterer, J.J.; Hovels, A.M.; Bosch, H.C. van den; Scheenen, T.W.J.; Hoogeveen, Y.L.; Barentsz, J.O.

    2006-01-01

    PURPOSE: To prospectively evaluate the feasibility of ferumoxtran-10-enhanced magnetic resonance (MR) imaging at high magnetic field strength (3.0 T) and to compare image quality between 1.5- and 3.0-T MR imaging in terms of lymph node detection in patients with prostate cancer. MATERIALS AND

  11. The value of diffusion tensor imaging in the differential diagnosis of subcortical ischemic vascular dementia and Alzheimer's disease in patients with only mild white matter alterations on T2-weighted images

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jian-Liang; Zhang, Ting (Dept. of Neurology, Shanghai Jiaotong Univ. Affiliated Sixth People' s Hospital, Shanghai (China)); Chang, Cheng; Zhang, Yu-Zhen; Li, Wen-Bin (Inst. of Diagnostic and Interventional Radiology, Shanghai Jiaotong Univ. Affiliated Sixth People' s Hospital, Shanghai (China)), Email: liwenbin@sh163.net

    2012-04-15

    Background: Diffusion tensor imaging (DTI) is a form of functional magnetic resonance imaging (MRI) that allows examination of the microstructural integrity of white matter in the brain. Dementia is a neurodegenerative disease, and DTI can provide indirect insights of the microstructural characteristics of brains in individuals with different forms of dementia. Purpose: To evaluate the value of DTI in the diagnosis and differential diagnosis of patients with subcortical ischemic vascular dementia (SIVD) and Alzheimer's disease (AD). Material and Methods: The study included 40 patients (20 AD patients and 20 SIVD patients) and 20 normal controls (NC). After routine MRI and DTI, fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were measured and compared in regions of interest (ROI). Results: Compared to NC and AD patients, SIVD patients had lower FA values and higher ADC values in the inferior-fronto-occipital fascicles (IFOF), genu of the corpus callosum (GCC), splenium of the corpus callosum (SCC), and superior longitudinal fasciculus (SLF). Compared to controls and SIVD patients, AD patients had lower FA values in the anterior frontal lobe, temporal lobe, hippocampus, IFOF, GCC, and CF; and higher ADC values in the temporal lobe and hippocampus. Conclusion: DTI can be used to estimate the white matter impairment in dementia patients. There were significant regional reductions of FA values and heightened ADC values in multiple regions in SIVD patients compared to AD patients. When compared with conventional MRI, DTI may provide a more objective method for the differential diagnosis of SIVD and AD disease patients who have only mild white matter alterations on T2-weighted imaging

  12. Role of magnetic susceptibility weighted imaging in evaluation of ...

    African Journals Online (AJOL)

    Introduction: Susceptibility-weighted imaging (SWI) is a new method in MR imaging. SWI detects the signal loss created by disturbance of a homogeneous magnetic field; these disturbances can be caused by paramagnetic, ferromagnetic, or diamagnetic substances. There are many neurologic conditions that can benefit ...

  13. Value of diffusion weighted magnetic resonance imaging in the ...

    African Journals Online (AJOL)

    Value of diffusion weighted magnetic resonance imaging in the prediction of cancer prostate. AHAA Afifi, AN Etaby, MAY Ahmad, YT Farghaly. Abstract. Introduction: Benign prostatic hyperplasia (BPH) and prostatic carcinoma (Pca) are the commonest diseases of the prostate with increased morbidities all over the world ...

  14. 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.

  15. Characterization of the collagen component of cartilage repair tissue of the talus with quantitative MRI: comparison of T2 relaxation time measurements with a diffusion-weighted double-echo steady-state sequence (dwDESS)

    Energy Technology Data Exchange (ETDEWEB)

    Kretzschmar, M.; Hainc, N.; Studler, U. [University Hospital Basel, Department of Radiology, Basel (Switzerland); Bieri, O. [University Hospital Basel, Division of Radiological Physics, Basel (Switzerland); Miska, M. [University Hospital, Department of Orthopedics, Heidelberg (Germany); Wiewiorski, M.; Valderrabano, V. [University Hospital Basel, Department of Orthopedic Surgery, Basel (Switzerland)

    2015-04-01

    The purpose of this study was to characterize the collagen component of repair tissue (RT) of the talus after autologous matrix-induced chondrogenesis (AMIC) using quantitative T2 and diffusion-weighted imaging. Mean T2 values and diffusion coefficients of AMIC-RT and normal cartilage of the talus of 25 patients with posttraumatic osteochondral lesions and AMIC repair were compared in a cross-sectional design using partially spoiled steady-state free precession (pSSFP) for T2 quantification, and diffusion-weighted double-echo steady-state (dwDESS) for diffusion measurement. RT and cartilage were graded with modified Noyes and MOCART scores on morphological sequences. An association between follow-up interval and quantitative MRI measures was assessed using multivariate regression, after stratifying the cohort according to time interval between surgery and MRI. Mean T2 of the AMIC-RT and cartilage were 43.1 ms and 39.1 ms, respectively (p = 0.26). Mean diffusivity of the RT (1.76 μm{sup 2}/ms) was significantly higher compared to normal cartilage (1.46 μm{sup 2}/ms) (p = 0.0092). No correlation was found between morphological and quantitative parameters. RT diffusivity was lowest in the subgroup with follow-up >28 months (p = 0.027). Compared to T2-mapping, dwDESS demonstrated greater sensitivity in detecting differences in the collagen matrix between AMIC-RT and cartilage. Decreased diffusivity in patients with longer follow-up times may indicate an increased matrix organization of RT. (orig.)

  16. 2D AMESING multi-echo (31)P-MRSI of the liver at 7T allows transverse relaxation assessment and T2-weighted averaging for improved SNR

    NARCIS (Netherlands)

    Runge, Jurgen Henk; van der Kemp, Wybe J M; Klomp, DWJ; Luijten, Peter R; Nederveen, Aart J; Stoker, Jaap

    PURPOSE: Liver diseases are a major global health concern often requiring invasive assessment by needle biopsy. (31)P magnetic resonance spectroscopic imaging (MRSI) allows non-invasive probing of important liver metabolites. Recently, the adiabatic multi-echo spectroscopic imaging sequence with

  17. 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

  18. Signal characteristics of focal bone marrow lesions in patients with multiple myeloma using whole body T1w-TSE, T2w-STIR and diffusion-weighted imaging with background suppression

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, Gregor; Bongartz, Georg; Winter, Leopold [University of Basel Hospital, Department of Radiology, Basel (Switzerland); Klarhoefer, Markus; Lenz, Claudia; Scheffler, Klaus [University of Basel Hospital, Department of Radiology, Division of Radiological Physics, Basel (Switzerland)

    2011-04-15

    This study analyses the diagnostic potential of Diffusion-Weighted Imaging with Background Suppression (DWIBS) in the detection of focal bone marrow lesions from multiple myeloma. The signal and contrast properties of DWIBS are evaluated in correlation with the serum concentration of M-component (MC) and compared with established T1- and T2-weighted sequences. Data from 103 consecutive studies in 81 patients are analysed retrospectively. Signal intensities and apparent Diffusion Coefficients (ADC) of 79 focal lesions in the lumbar spine or pelvis of 38 patients are determined and contrast-to-noise-ratio (CNR) is calculated. Data from patients with low (<20 g/L) and high (>20 g/dL) MC are evaluated separately. Signal intensities of focal myeloma lesions on T2w-STIR vary significantly depending on the MC, which leads to a loss in CNR in patients with high MC. No signal variation is observed for T1w-TSE and DWIBS. The CNR values provided by DWIBS in patients with high MC are slightly higher than those of T2w-STIR. ADC values in patients with low MC are significantly higher than in patients with high MC. Whole-body DWIBS has the potential to improve the conspicuity of focal myeloma lesions and provides additional biological information by ADC quantification. (orig.)

  19. 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 < 0.05), and between BMI and BMI %, and lipid-to-water ratios (P < 0.05). There was strong correlation between T2 fat values and lipid-to-water ratios (P < 0.0001, r = 0.83). T2 maps and MR spectroscopy correlate with physical characteristics associated with fatty infiltration of 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.

  20. Comparison of optimised endovaginal vs external array coil T2-weighted and diffusion-weighted imaging techniques for detecting suspected early stage (IA/IB1) uterine cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Downey, Kate; Morgan, Veronica A.; Giles, Sharon L.; MacDonald, A.; DeSouza, Nandita M. [The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, CRUK Cancer Imaging Centre, Surrey (United Kingdom); Attygalle, Ayoma D. [The Royal Marsden NHS Foundation Trust, Department of Histopathology, London (United Kingdom); Davis, M. [Kingston Hospital, Department of Gynaecology, Kingston-upon-Thames, Surrey (United Kingdom); Ind, Thomas E.J.; Shepherd, John H. [The Royal Marsden NHS Foundation Trust, Gynecology Unit, London (United Kingdom)

    2016-04-15

    To compare sensitivity and specificity of endovaginal versus external-array coil T2-W and T2-W + DWI for detecting and staging small cervical tumours. Optimised endovaginal and external array coil MRI at 3.0-T was done prospectively in 48 consecutive patients with stage Ia/Ib1 cervical cancer. Sensitivity/specificity for detecting tumour and parametrial extension against histopathology for a reading radiologist were determined on coronal T2-W and T2W + DW images. An independent radiologist also scored T2-W images without and with addition of DWI for the external-array and endovaginal coils on separate occasions >2 weeks apart. Cohen's kappa assessed inter- and intra-observer agreement. Median tumour volume in 19/38 cases positive on subsequent histology was 1.75 cm{sup 3}. Sensitivity, specificity, PPV, NPV were: reading radiologist 91.3 %, 89.5 %, 91.3 %, 89.5 %, respectively; independent radiologist T2-W 82.6 %, 73.7 %, 79.1 %, 77.8 % for endovaginal, 73.9 %, 89.5 %, 89.5 %, 73.9 % for external-array coil. Adding DWI improved sensitivity and specificity of endovaginal imaging (78.2 %, 89.5 %); adding DWI to external-array imaging improved specificity (94.7 %) but reduced sensitivity (66.7 %). Inter- and intra-observer agreement on T2-W + DWI was good (kappa = 0.67 and 0.62, respectively). Endovaginal coil T2-W MRI is more sensitive than external-array coil for detecting tumours <2 cm{sup 3}; adding DWI improves specificity of endovaginal imaging but reduces sensitivity of external-array imaging. (orig.)

  1. Field Balancing of Magnetically Levitated Rotors without Trial Weights

    Directory of Open Access Journals (Sweden)

    Jiancheng Fang

    2013-11-01

    Full Text Available Unbalance in magnetically levitated rotor (MLR can cause undesirable synchronous vibrations and lead to the saturation of the magnetic actuator. Dynamic balancing is an important way to solve these problems. However, the traditional balancing methods, using rotor displacement to estimate a rotor’s unbalance, requiring several trial-runs, are neither precise nor efficient. This paper presents a new balancing method for an MLR without trial weights. In this method, the rotor is forced to rotate around its geometric axis. The coil currents of magnetic bearing, rather than rotor displacement, are employed to calculate the correction masses. This method provides two benefits when the MLR’s rotation axis coincides with the geometric axis: one is that unbalanced centrifugal force/torque equals the synchronous magnetic force/torque, and the other is that the magnetic force is proportional to the control current. These make calculation of the correction masses by measuring coil current with only a single start-up precise. An unbalance compensation control (UCC method, using a general band-pass filter (GPF to make the MLR spin around its geometric axis is also discussed. Experimental results show that the novel balancing method can remove more than 92.7% of the rotor unbalance and a balancing accuracy of 0.024 g mm kg−1 is achieved.

  2. T2-weighted MR imaging of liver lesions: a prospective evaluation comparing turbo spin-echo, breath-hold turbo spin-echo and half-Fourier turbo spin-echo (HASTE) sequences; Estudio de lesiones hepaticas con imagenes de resonancia magnetica potenciadas en T2: evaluacion prospectiva comparando secuencias turbo eco del espin, turbo eco del espin con respiracion sostenida y half-Fourier turbo eco del espin (HASTE)

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J.; Villajos, M.; Oses, M. J.; Veintemillas, M.; Rue, M.; Puig, J.; Sentis, M. [Fundacion Parc Tauli. Sabadell (Spain)

    2000-07-01

    To compare turbo spin-echo (TSE), breath-hold TSE and half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences quantitatively and qualitatively in T2-weighted images of liver lesions. The authors evaluated prospectively 89 liver lesions in 73 patients using a 1.0-T magnetic resonance system to compare TSE, breath-hold TSE and HASTE sequences. The quantitative parameters were: lesion-to-liver contrast and lesion-to-liver contrast-to-noise ratio. The qualitative analysis was performed by two observers in consensus who examined four parameters: respiratory artifacts, lesion edge definition, intrahepatic vessel definition and image quality. Repeated measures analysis of variance was utilized to compare the quantitative variables and Friedman's nonparametric test for the qualitative parameters. In quantitative terms, the lesion-to-liver contrast was similar in TSE and breath-hold TSE sequences (2.45{+-}1.44 versus 2.60{+-}1.66), both of which were significantly better than the HASTE sequence (1.12{+-}0.72; p<0.001). The lesion-to-liver contrast-to-noise ratio was significantly higher in the TSE sequence (62.60{+-}46.40 versus 40.22{+-}25.35 versus 50.90{+-}32.10 for TSE, breath-hold TSE and HASTE sequences, respectively; p<0.001). In the qualitative comparisons, the HASTE sequence was significantly better than the TSE and breath-hold TSE sequences (p<0.001) in terms of artifacts and definition of lesion edge and intrahepatic vessels. Image quality was also significantly greater in the HASTE sequence (p<0.001). In quantitative terms, the TSE sequence is better than the breath-hold TSE and HASTE sequences, but there are no movement artifacts in the HASTE sequence, which is also significantly superior to TSE and breath-hold TSE sequences in qualitative terms and, thus, can be employed for T2-weighted images in liver studies. (Author) 17 refs.

  3. 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.

  4. MRI texture analysis (MRTA) of T2-weighted images in Crohn's disease may provide information on histological and MRI disease activity in patients undergoing ileal resection

    Energy Technology Data Exchange (ETDEWEB)

    Makanyanga, Jesica; Bhatnagar, Gauraang; Halligan, Steve; Taylor, Stuart A. [University College London and University College London Hospitals NIHR Biomedical Research Centre, Center for Medical Imaging, London (United Kingdom); Ganeshan, Balaji; Groves, Ashley; Miles, Ken [University College London, University College Hospital, Institute of Nuclear Medicine, London (United Kingdom); Rodriguez-Justo, Manuel [University College London, Department of Research Pathology, University College London Cancer Institute, London (United Kingdom)

    2017-02-15

    To associate MRI textural analysis (MRTA) with MRI and histological Crohn's disease (CD) activity. Sixteen patients (mean age 39.5 years, 9 male) undergoing MR enterography before ileal resection were retrospectively analysed. Thirty-six small (≤3 mm) ROIs were placed on T2-weighted images and location-matched histological acute inflammatory scores (AIS) measured. MRI activity (mural thickness, T2 signal, T1 enhancement) (CDA) was scored in large ROIs. MRTA features (mean, standard deviation, mean of positive pixels (MPP), entropy, kurtosis, skewness) were extracted using a filtration histogram technique. Spatial scale filtration (SSF) ranged from 2 to 5 mm. Regression (linear/logistic) tested associations between MRTA and AIS (small ROIs), and CDA/constituent parameters (large ROIs). Skewness (SSF = 2 mm) was associated with AIS [regression coefficient (rc) 4.27, p = 0.02]. Of 120 large ROI analyses (for each MRI, MRTA feature and SSF), 15 were significant. Entropy (SSF = 2, 3 mm) and kurtosis (SSF = 3 mm) were associated with CDA (rc 0.9, 1.0, -0.45, p = 0.006-0.01). Entropy and mean (SSF = 2-4 mm) were associated with T2 signal [odds ratio (OR) 2.32-3.16, p = 0.02-0.004], [OR 1.22-1.28, p = 0.03-0.04]. MPP (SSF = 2 mm) was associated with mural thickness (OR 0.91, p = 0.04). Kurtosis (SSF = 3 mm), standard deviation (SSF = 5 mm) were associated with decreased T1 enhancement (OR 0.59, 0.42, p = 0.004, 0.007). MRTA features may be associated with CD activity. (orig.)

  5. Interim heterogeneity changes measured using entropy texture features on T2-weighted MRI at 3.0 T are associated with pathological response to neoadjuvant chemotherapy in primary breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Shelley; Lerski, Richard [Ninewells Hospital and Medical School, Department of Medical Physics, Dundee (United Kingdom); Purdie, Colin [Ninewells Hospital and Medical School, Department of Pathology, Dundee (United Kingdom); Michie, Caroline [Ninewells Hospital and Medical School, Department of Oncology, Dundee (United Kingdom); Evans, Andrew; Vinnicombe, Sarah [University of Dundee, Division of Imaging and Technology, Ninewells Hospital and Medical School, Dundee (United Kingdom); Johnston, Marilyn [Ninewells Hospital and Medical School, Department of Clinical Radiology, Dundee (United Kingdom); Thompson, Alastair M. [University of Texas MD Anderson Cancer Centre, Department of Breast Surgical Oncology, Houston, TX (United States)

    2017-11-15

    To investigate whether interim changes in hetereogeneity (measured using entropy features) on MRI were associated with pathological residual cancer burden (RCB) at final surgery in patients receiving neoadjuvant chemotherapy (NAC) for primary breast cancer. This was a retrospective study of 88 consenting women (age: 30-79 years). Scanning was performed on a 3.0 T MRI scanner prior to NAC (baseline) and after 2-3 cycles of treatment (interim). Entropy was derived from the grey-level co-occurrence matrix, on slice-matched baseline/interim T2-weighted images. Response, assessed using RCB score on surgically resected specimens, was compared statistically with entropy/heterogeneity changes and ROC analysis performed. Association of pCR within each tumour immunophenotype was evaluated. Mean entropy percent differences between examinations, by response category, were: pCR: 32.8%, RCB-I: 10.5%, RCB-II: 9.7% and RCB-III: 3.0%. Association of ultimate pCR with coarse entropy changes between baseline/interim MRI across all lesions yielded 85.2% accuracy (area under ROC curve: 0.845). Excellent sensitivity/specificity was obtained for pCR prediction within each immunophenotype: ER+: 100%/100%; HER2+: 83.3%/95.7%, TNBC: 87.5%/80.0%. Lesion T2 heterogeneity changes are associated with response to NAC using RCB scores, particularly for pCR, and can be useful across all immunophenotypes with good diagnostic accuracy. (orig.)

  6. T2{sup *} mapping from multi-echo dixon sequence on gadoxetic acid-enhanced magnetic resonance imaging for the hepatic fat quantification: Can it be used for hepatic function assessment?

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hyun Suk; Lee, Jeong Min; Yoon, Jeong Hee; Kang, Hyo Jin; Lee, Sang Min; Yang, Hyun Kyung; Han, Joon Koo [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2017-08-01

    To evaluate the diagnostic value of T2{sup *} mapping using 3D multi-echo Dixon gradient echo acquisition on gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) as a tool to evaluate hepatic function. This retrospective study was approved by the IRB and the requirement of informed consent was waived. 242 patients who underwent liver MRIs, including 3D multi-echo Dixon fast gradient-recalled echo (GRE) sequence at 3T, before and after administration of gadoxetic acid, were included. Based on clinico-laboratory manifestation, the patients were classified as having normal liver function (NLF, n = 50), mild liver damage (MLD, n = 143), or severe liver damage (SLD, n = 30). The 3D multi-echo Dixon GRE sequence was obtained before, and 10 minutes after, gadoxetic acid administration. Pre- and post-contrast T2{sup *} values, as well as T2{sup *} reduction rates, were measured from T2{sup *} maps, and compared among the three groups. There was a significant difference in T2{sup *} reduction rates between the NLF and SLD groups (−0.2 ± 4.9% vs. 5.0 ± 6.9%, p = 0.002), and between the MLD and SLD groups (3.2 ± 6.0% vs. 5.0 ± 6.9%, p = 0.003). However, there was no significant difference in both the pre- and post-contrast T2{sup *} values among different liver function groups (p = 0.735 and 0.131, respectively). A receiver operating characteristic (ROC) curve analysis showed that the area under the ROC curve for using T2{sup *} reduction rates to differentiate the SLD group from the NLF group was 0.74 (95% confidence interval: 0.63–0.83). Incorporation of T2{sup *} mapping using 3D multi-echo Dixon GRE sequence in gadoxetic acid-enhanced liver MRI protocol may provide supplemental information for liver function deterioration in patients with SLD.

  7. Simple recipe for accurate T(2) quantification with multi spin-echo acquisitions.

    Science.gov (United States)

    Neumann, Daniel; Blaimer, Martin; Jakob, Peter M; Breuer, Felix A

    2014-12-01

    The quantification of magnetic resonance relaxation parameters T 1 and T 2 have the potential for improved disease detection and classification over standard clinical weighted imaging. Performing a mono-exponential fit on multi spin-echo (MSE) data provides quantitative T 2 values in a clinically acceptable scan-time. However, due to technical imperfections of refocusing pulses, stimulated echo contributions to the signals lead to significant deviations in the resulting T 2 values. In this work, a simple auto-calibrating correction procedure is presented, allowing the accurate estimation of T 2 from MSE acquisitions. Correction factors for T 2 values obtained from MSE acquisitions with a mono-exponential fit are derived from simulations following the extended phase graph formulation. A closed formula is given for the calculation of the required correction factors directly from the measured data itself. Simulations and phantom experiments show high accuracy of corrected T 2 values for a wide range of clinically relevant T 2 values and for different nominal refocusing flip angles. In addition, corrected T 2 maps of the human brain are presented. A simple recipe is provided to correct T 2 values obtained from MSE acquisitions via a mono-exponential fit for the influence of stimulated echoes. Since all required parameters are extracted from the data themselves, no additional acquisitions are required.

  8. 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.)

  9. Comparison of the T2-star Values of Placentas Obtained from Pre-eclamptic Patients with Those of a Control Group: an Ex-vivo Magnetic Resonance Imaging Study.

    Science.gov (United States)

    Yurttutan, Nursel; Bakacak, Murat; Kızıldağ, Betül

    2017-09-29

    Endotel dysfunction, vasoconstriction, and oxidative stress are described in the pathophysiology of pre-eclampsia, but its aetiology has not been revealed clearly. To examine whether there is a difference between the placentas of pre-eclamptic pregnant women and those of a control group in terms of their T2 star values. Case-control study. Twenty patients diagnosed with pre-eclampsia and 22 healthy controls were included in this study. The placentas obtained after births performed via Caesarean section were taken into the magnetic resonance imaging area in plastic bags within the first postnatal hour, and imaging was performed via modified DIXON-Quant sequence. Average values were obtained by performing T2 star measurements from four localisations on the placentas. T2 star values measured in the placentas of the control group were found to be significantly lower than those in the pre-eclampsia group (pvalue in the pre-eclamptic group was found to be 37.48 ms (standard deviation ± 11.3), this value was 28.74 (standard deviation ± 8.08) in the control group. The cut-off value for the T2 star value, maximising the accuracy of diagnosis, was 28.59 ms (area under curve: 0.741; 95% confidence interval: 0.592-0.890); sensitivity and specificity were 70% and 63.6%, respectively. This study, the T2 star value, which is an indicator of iron amount, was found to be significantly lower in the control group than in the pre-eclampsia group. This may be related to the reduction in blood flow to the placenta due to endothelial dysfunction and vasoconstriction, which are important in pre-eclampsia pathophysiology.

  10. Myocardial and liver iron overload, assessed using T2* magnetic resonance imaging with an excel spreadsheet for post processing in Tunisian thalassemia major patients.

    Science.gov (United States)

    Ouederni, Monia; Ben Khaled, Monia; Mellouli, Fethi; Ben Fraj, Elhem; Dhouib, Nawel; Yakoub, Ismehen Ben; Abbes, Selem; Mnif, Nejla; Bejaoui, Mohamed

    2017-01-01

    Thalassemia is a common genetic disorder in Tunisia. Early iron concentration assessment is a crucial and challenging issue. Most of annual deaths due to iron overload occurred in underdeveloped regions of the world. Limited access to liver and heart MRI monitoring might partially explain these poor prognostic results. Standard software programs are not available in Tunisia. This study is the first to evaluate iron overload in heart and liver using the MRI T2* with excel spreadsheet for post processing. Association of this MRI tool results to serum ferritin level, and echocardiography was also investigated. One hundred Tunisian-transfused thalassemia patients older than 10 years (16.1 ± 5.2) were enrolled in the study. The mean myocardial iron concentration (MIC) was 1.26 ± 1.65 mg/g dw (0.06-8.32). Cardiac T2* (CT2*) was under 20 ms in 30 % of patients and under 10 ms in 21 % of patients. Left ventricular ejection function was significantly lower in patients with CT2* 3 mg/g dw) was found in 95 % of patients. LIC was over 15 mg/g dw in 25 % of patients. MIC was more correlated than CT2* to LIC and serum ferritin. Among patients with SF excel spreadsheet for routine follow-up of iron overload might improve the prognosis of thalassemia major patients in developing countries, such as Tunisia, where standard MRI tools are not available or expensive.

  11. Quantitative T2 Combined with Texture Analysis of Nuclear Magnetic Resonance Images Identify Different Degrees of Muscle Involvement in Three Mouse Models of Muscle Dystrophy: mdx, Largemyd and mdx/Largemyd

    Science.gov (United States)

    Martins-Bach, Aurea B.; Malheiros, Jackeline; Matot, Béatrice; Martins, Poliana C. M.; Almeida, Camila F.; Caldeira, Waldir; Ribeiro, Alberto F.; Loureiro de Sousa, Paulo; Azzabou, Noura; Tannús, Alberto; Carlier, Pierre G.; Vainzof, Mariz

    2015-01-01

    Quantitative nuclear magnetic resonance imaging (MRI) has been considered a promising non-invasive tool for monitoring therapeutic essays in small size mouse models of muscular dystrophies. Here, we combined MRI (anatomical images and transverse relaxation time constant—T2—measurements) to texture analyses in the study of four mouse strains covering a wide range of dystrophic phenotypes. Two still unexplored mouse models of muscular dystrophies were analyzed: The severely affected Largemyd mouse and the recently generated and worst double mutant mdx/Largemyd mouse, as compared to the mildly affected mdx and normal mice. The results were compared to histopathological findings. MRI showed increased intermuscular fat and higher muscle T2 in the three dystrophic mouse models when compared to the wild-type mice (T2: mdx/Largemyd: 37.6±2.8 ms; mdx: 35.2±4.5 ms; Largemyd: 36.6±4.0 ms; wild-type: 29.1±1.8 ms, p<0.05), in addition to higher muscle T2 in the mdx/Largemyd mice when compared to mdx (p<0.05). The areas with increased muscle T2 in the MRI correlated spatially with the identified histopathological alterations such as necrosis, inflammation, degeneration and regeneration foci. Nevertheless, muscle T2 values were not correlated with the severity of the phenotype in the 3 dystrophic mouse strains, since the severely affected Largemyd showed similar values than both the mild mdx and worst mdx/Largemyd lineages. On the other hand, all studied mouse strains could be unambiguously identified with texture analysis, which reflected the observed differences in the distribution of signals in muscle MRI. Thus, combined T2 intensity maps and texture analysis is a powerful approach for the characterization and differentiation of dystrophic muscles with diverse genotypes and phenotypes. These new findings provide important noninvasive tools in the evaluation of the efficacy of new therapies, and most importantly, can be directly applied in human translational research

  12. Sclerosing perineurioma: tumor of the hand with a short T2

    International Nuclear Information System (INIS)

    Miyake, Mototaka; Tateishi, Ukihide; Maeda, Tetsuo; Arai, Yasuaki; Seki, Kunihiko; Hasegawa, Tadashi; Sugimura, Kazuro

    2006-01-01

    We present two cases of sclerosing perineurioma, a rare soft tissue tumor, in the palm and the ring finger respectively, presenting as a small, painless and subcutaneous mass. This tumor has a predilection for the digits and palms of young, predominantly male adults. In the present cases the tumors showed very low signal intensity on T2-weighted magnetic resonance (MR) images. Histologically they contained abundant collagen and hyalinized stroma, which would account for areas of low signal intensity on T2-weighted MR images. Immunohistochemically, the tumor cells were positive for vimentin, epithelial membrane antigen and human erythrocyte glucose transporter 1 and negative for S-100 protein. To the best of our knowledge, the appearance of sclerosing perineurioma on MR imaging has not been previously reported in the English-language literature. Sclerosing perineurioma should be considered in the differential diagnosis of hand tumors when the tumor shows low signal intensity on T2-weighted MR images. (orig.)

  13. Local T1-T2distribution measurements in porous media.

    Science.gov (United States)

    Vashaee, S; Li, M; Newling, B; MacMillan, B; Marica, F; Kwak, H T; Gao, J; Al-Harbi, A M; Balcom, B J

    2018-02-01

    A novel slice-selective T 1 -T 2 measurement is proposed to measure spatially resolved T 1 -T 2 distributions. An adiabatic inversion pulse is employed for slice-selection. The slice-selective pulse is able to select a quasi-rectangular slice, on the order of 1 mm, at an arbitrary position within the sample.The method does not employ conventional selective excitation in which selective excitation is often accomplished by rotation of the longitudinal magnetization in the slice of interest into the transverse plane, but rather a subtraction based on CPMG data acquired with and without adiabatic inversion slice selection. T 1 weighting is introduced during recovery from the inversion associated with slice selection. The local T 1 -T 2 distributions measured are of similar quality to bulk T 1 -T 2 measurements. The new method can be employed to characterize oil-water mixtures and other fluids in porous media. The method is beneficial when a coarse spatial distribution of the components is of interest. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Dark blood versus bright blood T2* acquisition in cardiovascular magnetic resonance (CMR) for thalassaemia major (TM) patients: Evaluation of feasibility, reproducibility and image quality

    International Nuclear Information System (INIS)

    Liguori, Carlo; Di Giampietro, Ilenia; Pitocco, Francesca; De Vivo, Aldo Eros; Schena, Emiliano; Mortato, Luca; Pirro, Federica; Cianciulli, Paolo; Zobel, Bruno Beomonte

    2014-01-01

    Objectives: To compare the effectiveness of dark blood (DB) versus bright blood (BB) sequences. To assess the intra and inter-observer variability and inter-study reproducibility between BB versus DB. To evaluate image quality level in the two sequences. Methods: In a setting of 138 patients we performed CMR using cardiac gated Gradient-multiecho single breath-hold BB and DB sequences in the middle ventricular septum. Each acquisition was repeated during the same exam. Truncation method was used to account for background noise. Image quality (IQ) was assessed using a 5 point grading scale and image analysis was conducted by 2 experienced observers. Results: Compared with the conventional BB acquisition, the coefficient of correlation and significance of the DB technique was superior for intra-observer reproducibility (p < 0.001), inter-observer reproducibility (p < 0.001) and inter-study reproducibility (p < 0.001). The variability is also lower for DB sequences for T2* values <14 ms. Assessment of artifacts showed a superior score for DB versus BB scans (4 versus 3, p < 0.001). Conclusions: Improvement in terms of inter observer and inter study variability using DB sequences was obtained. The greatest disparity between them was seen in inter-study reproducibility and higher IQ in DB was seen. Study demonstrates better performance of DB imaging compared to BB in presence of comparable effectiveness

  15. Dark blood versus bright blood T2* acquisition in cardiovascular magnetic resonance (CMR) for thalassaemia major (TM) patients: Evaluation of feasibility, reproducibility and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Liguori, Carlo, E-mail: c.liguori@unicampus.it [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Di Giampietro, Ilenia; Pitocco, Francesca; De Vivo, Aldo Eros [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Schena, Emiliano [Unit of Measurements and Biomedical Instrumentation, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Mortato, Luca [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy); Pirro, Federica [Department of Biomaging and Radiological Sciences, Catholic University of Sacred Herart, Largo A. Gemelli 1, 00135 Rome (Italy); Cianciulli, Paolo [Thalassemia Unit, Ospedale Sant Eugenio, Piazzale dell’Umanesimo 10, 00143 Rome (Italy); Zobel, Bruno Beomonte [Department of Diagnostic Imaging, Campus Bio Medico University, via Alvaro del Portillo 200, 00128 Rome (Italy)

    2014-01-15

    Objectives: To compare the effectiveness of dark blood (DB) versus bright blood (BB) sequences. To assess the intra and inter-observer variability and inter-study reproducibility between BB versus DB. To evaluate image quality level in the two sequences. Methods: In a setting of 138 patients we performed CMR using cardiac gated Gradient-multiecho single breath-hold BB and DB sequences in the middle ventricular septum. Each acquisition was repeated during the same exam. Truncation method was used to account for background noise. Image quality (IQ) was assessed using a 5 point grading scale and image analysis was conducted by 2 experienced observers. Results: Compared with the conventional BB acquisition, the coefficient of correlation and significance of the DB technique was superior for intra-observer reproducibility (p < 0.001), inter-observer reproducibility (p < 0.001) and inter-study reproducibility (p < 0.001). The variability is also lower for DB sequences for T2* values <14 ms. Assessment of artifacts showed a superior score for DB versus BB scans (4 versus 3, p < 0.001). Conclusions: Improvement in terms of inter observer and inter study variability using DB sequences was obtained. The greatest disparity between them was seen in inter-study reproducibility and higher IQ in DB was seen. Study demonstrates better performance of DB imaging compared to BB in presence of comparable effectiveness.

  16. Evaluation of the embolic effect of polyvinyl alcohol foam particles according to particle size on the cerebral artery of a cat, focusing on T2 weighted MR images and pathologic study after 24 hours

    International Nuclear Information System (INIS)

    Park, Man Soo; Woo, Don Hee; Chung, Haingsub R.; Kang Gil Hyun; Lee, Sang Youl; Ryu, Dae Sik; Lee, Yong Chul

    2000-01-01

    This study was designed to determine the embolic effect of PVA particles of various sizes on the cerebral artery of a cat and to determine the appropriate particle size for embolization. A total of 21 cats were divided into three groups according to the PVA particle size injected: group I (n=3D7), embolized with 45-150μm PVA; group II (n=3D7), with 150-250μm PVA; and group III (n=3D7), with 350-500μm PVA. PVA particles were slowly injected into the left common carotid artery of each cat, and T2-weighted coronal MR images were obtained 24 hours after injection. During histologic examination of brain sections we analyzed the size, number of occluded vessels, and the ischemic changes caused by the particles. On T2 weighted images, areas of high signal intensity (infarction) were observed in four of the seven cats (57%) in group I and in two of the seven (29%) II. High signal intensity was not found in group III. The mean percentage of areas of high signal intensity was 11.86 ± 1.37% in group I and 5.18 ± 1.77% in group II (P less than 0.05). During histologic examination, occlusion of the distal branches of the anterior cerebral (ACA) and/or the middle cerebral arteries (MCA) by PVA particles was observed in all seven cats (100%) in group I, and in four of the seven cats (57%) in group II, No group III cat showed occlusion of the distal branches of the ACA and/or MCA. The mean caliber of occluded vessels was 175μm in Group I and 258μm in Group II. The mean number of occluded vessels seen on all slide sections was 14 in Group I and 5 in Group II. Small PVA particles has a greater cerebral embolic effect than did those which were medium or large. For the induction of embolic infarction in cat brain, PVA particles 45-150μm in size are appropriate. (author)

  17. Diagnosis of nerve root compromise of the lumbar spine: Evaluation of the performance of three-dimensional isotropic T2-weighted turbo spin-echo SPACE sequence at 3T

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Jin Kyeong; Jee, Won Hee; Jung, Joon Yong; Jang, Jin Hee; Kim, Jin Sung; Kim, Young Hoon; Ha, Kee Yong [Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)

    2017-01-15

    To explore the performance of three-dimensional (3D) isotropic T2-weighted turbo spin-echo (TSE) sampling perfection with application optimized contrasts using different flip angle evolution (SPACE) sequence on a 3T system, for the evaluation of nerve root compromise by disc herniation or stenosis from central to extraforaminal location of the lumbar spine, when used alone or in combination with conventional two-dimensional (2D) TSE sequence. Thirty-seven patients who had undergone 3T spine MRI including 2D and 3D sequences, and had subsequent spine surgery for nerve root compromise at a total of 39 nerve levels, were analyzed. A total of 78 nerve roots (48 symptomatic and 30 asymptomatic sites) were graded (0 to 3) using different MRI sets of 2D, 3D (axial plus sagittal), 3D (all planes), and combination of 2D and 3D sequences, with respect to the nerve root compromise caused by posterior disc herniations, lateral recess stenoses, neural foraminal stenoses, or extraforaminal disc herniations; grading was done independently by two readers. Diagnostic performance was compared between different imaging sets using the receiver operating characteristics (ROC) curve analysis. There were no statistically significant differences (p = 0.203 to > 0.999) in the ROC curve area between the imaging sets for both readers 1 and 2, except for combined 2D and 3D (0.843) vs. 2D (0.802) for reader 1 (p = 0.035), and combined 2D and 3D (0.820) vs. 3D including all planes (0.765) for reader 2 (p = 0.049). The performance of 3D isotropic T2-weighted TSE sequence of the lumbar spine, whether axial plus sagittal images, or all planes of images, was not significantly different from that of 2D TSE sequences, for the evaluation of nerve root compromise of the lumbar spine. Combining 2D and 3D might possibly improve the diagnostic accuracy compared with either one.

  18. P, = C ~ !~, 1 ~ t2 )

    Indian Academy of Sciences (India)

    P, = C ~ !~, 1 ~ t2 ). (1). Observe that if t is rational, then Pt is a rational point; that is, its coordinates are rational. (This formula permits us, in principle, to enumerate all rational points on C.) Let. B denote the point (1,0). Then APt = 2/V'f+t2 and. B Pt = 2t / V'f+t2, so if t is such that t and J 1 + t2 are rational, then IAPtl and IBPtl ...

  19. Diffusion-weighted magnetic resonance imaging in ileocolonic Crohn's disease

    DEFF Research Database (Denmark)

    Juel, Mie A; Rafaelsen, Søren Rafael; Nathan, Torben

    protocol contained coronal e-thrive and SShT2 with free-breathing and a factor b fixed at 800 s/mm2. Patients were examined in the prone position before and after intravenous administration of 20 mg Hyoscin Butylbromide (Buscopan®, Boehringer Ingelheim, Basel, Switzerland). Ileocolonoscopy with Simple...

  20. Superficial siderosis of the central nervous system induced by a single-episode of traumatic subarachnoid hemorrhage: a study using MRI-enhanced gradient echo T2 star-weighted angiography.

    Directory of Open Access Journals (Sweden)

    Hongwei Zhao

    Full Text Available The purpose of this study was to examine whether a single episode of traumatic subarachnoid hemorrhage (tSAH could cause superficial siderosis of the central nervous system (SS-CNS.This study was approved by the local ethics committee. Thirty-two patients with a history of a single episode of tSAH were enrolled in the study. An episode of tSAH was confirmed in patients based on a CT scan or a lumbar puncture, and a follow-up examination was conducted at least six weeks after the brain trauma. A follow-up MRI examination was performed, using enhanced gradient echo T2 star-weighted angiography (ESWAN to detect hemosiderin deposition on the cortical surface. The extent to which hemosiderin deposition was associated with several clinical factors was investigated. Various degrees of hemosiderin deposition were detected in 31 of 32 (96.9% single-episode tSAH patients. Analysis of contingency tables revealed an association between the regions of subarachnoid bleeding based on CT images and the regions of hemosiderin deposition based on ESWAN images (χ2 = 17.73, P<0.05. SS-CNS was determined to be a common consequence after a single episode of tSAH. The extent of hemosiderin deposition is closely correlated with the initial bleeding sites and bleeding volume.

  1. Comparison of conventional spin-echo, turbo spin-echo and respiratory-triggering turbo spin-echo pulse sequences for T2-weighted MR imaging of hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Date, Shuji; Kimura, Fumiko; Ito, Katsuhide.

    1996-01-01

    T 2 -weighted conventional spin-echo (CSE), turbo spin-echo (TSE) and respiratory-triggering turbo spin-echo (RT-TSE) images were compared to determine there efficacy in the diagnosis of hepatocellular carcinoma (HCC). A total of 32 patients with 40 HCCs was examined in this study. Both CSE and RT-TSE images were obtained in all the patients, and in addition conventional TSE images were obtained in 10 patients with 17 HCCs. Quantitative analysis demonstrated that RT-TSE had the highest lesion-liver contrast-to-noise ratio (7.8) and that CSE had the lowest ratio (5.6) (p<0.001). Since qualitative analysis (tissue contrast and conspicuousness of lesions) showed that TSE was inferior to the other sequences, TSE might be less suitable for the depiction of HCC. RT-TSE, however, had the highest assessment in qualitative analysis probably due to reduced respiratory motion artifacts especially at the subphrenic region and at the area adjacent to the gall bladder. It is concluded from the results of the present study that RT-TSE has a potential value as a routine sequence for the detection of HCC. (author)

  2. Everyman's prostate phantom: kiwi-fruit substitute for human prostates at magnetic resonance imaging, diffusion-weighted imaging and magnetic resonance spectroscopy.

    Science.gov (United States)

    Mueller-Lisse, Ullrich G; Murer, Sophie; Mueller-Lisse, Ulrike L; Kuhn, Marissa; Scheidler, Juergen; Scherr, Michael

    2017-08-01

    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 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 2 /s × 10 -3 ) resembled PZ and TZ (1.39 ± 0.17-1.60 ± 0.24 mm 2 /s × 10 -3 ), while CP (0.91 ± 0.14-0.99 ± 0.10 mm 2 /s × 10 -3 ) resembled Gleason 7b-9 prostate cancer (1.00 ± 0.25 mm 2 /s × 10 -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. • Kiwi fruit appear suitable as phantoms for human prostate in MR examinations. • Kiwi fruit show zonal anatomy like human prostates in T2-weighted MRI and DWI. • MR spectroscopy reliably shows peaks in kiwi fruit (citrate/inositol) and human prostates (citrate

  3. Radiation effects in the rat spinal cord: evaluation with apparent diffusion coefficient versus T2 at serial MR imaging.

    Science.gov (United States)

    Philippens, Marielle E P; Gambarota, Giulio; van der Kogel, Albert J; Heerschap, Arend

    2009-02-01

    To prospectively determine whether apparent diffusion coefficients (ADCs) are more sensitive to radiation-induced changes in the rat spinal cord than T2 relaxation times. The study was approved by the institutional ethical committee on animal welfare. One centimeter of the thoracolumbar spinal cord of six rats was irradiated with 36 Gy. For 3-6 months after irradiation, five 7.0-T magnetic resonance (MR) imaging measurements were performed in each rat until motor impairment developed. Six age-matched rats were examined as controls. Measurements were performed by using diffusion-weighted imaging with five b values and a spin-echo sequence with 20 echoes. ADC and T2 values were calculated, and the spatiotemporal evolution of the radiation-induced lesions was determined semiautomatically. The final MR measurements were compared with the histologic findings. Shortly before the neurologic signs appeared, the first radiation effects manifested as well-circumscribed white matter (WM) lesions with a low longitudinal ADC and normal or high T2. WM lesions with high T2 correlated with confluent necrosis at histologic analysis, whereas WM lesions with normal T2 correlated with focal necrosis and demyelination. In the gray matter (GM), lesions with diffusely high T2 were present and were attributed to edema. T2 changes in the GM preceded T2 and ADC changes in the WM. In the WM, longitudinal ADC was more sensitive for the detection of radiation damage than T2, but in the GM, T2 was more sensitive.

  4. MO-G-18C-07: Improving T2 Determination and Quantification of Lipid Methylene Protons in Proton Magnetic Resonance Spectroscopy at 3 T

    Energy Technology Data Exchange (ETDEWEB)

    Breitkreutz, D. [of Oncology, University of Alberta, Edmonton, AB (Canada); Fallone, B. G.; Yahya, A. [of Oncology, University of Alberta, Edmonton, AB (Canada); Department of Medical Physics, Cross Cancer Institute, Edmonton, AB (Canada)

    2014-06-15

    Purpose: To improve proton magnetic resonance spectroscopy (MRS) transverse relaxation (T{sub 2}) determination and quantification of lipid methylene chain (1.3 ppm) protons by rewinding their J-coupling evolution. Methods: MRS experiments were performed on four lipid phantoms, namely, almond, corn, sunflower and oleic acid, using a 3 T Philips MRI scanner with a transmit/receive birdcage head coil. Two PRESS (Point RESolved Spectroscopy) pulse sequences were used. The first PRESS sequence employed standard bandwidth (BW) (∼550 Hz) RF (radiofrequency) refocussing pulses, while the second used refocussing pulses of narrow BW (∼50 Hz) designed to rewind J-coupling evolution of the methylene protons in the voxel of interest. Signal was acquired with each sequence from a 5×5×5 mm{sup 3} voxel, with a repetition time (TR) of 3000 ms, and with echo times (TE) of 100 to 200 ms in steps of 20 ms. 2048 sample points were measured with a 2000 Hz sampling bandwidth. Additionally, 30 mm outer volume suppression slabs were used to suppress signal outside the voxel of interest. The frequency of the RF pulses was set to that of the methylene resonance. Methylene peak areas were calculated and fitted in MATLAB to a monexponentially decaying function of the form M{sub 0}exp(-TE/T{sub 2}), where M{sub 0} is the extrapolated area when TE = 0 ms and yields a measure of concentration. Results: The determined values of M{sub 0} and T{sub 2} increased for all fatty acids when using the PRESS sequence with narrow BW refocussing pulses. M{sub 0} and T{sub 2} values increased by an average amount (over all the phantoms) of 31% and 14%, respectively. Conclusion: This investigation has demonstrated that J-coupling interactions of lipid methylene protons causes non-negligible signal losses which, if not accounted for, Result in underestimations of their levels and T{sub 2} values when performing MRS measurements. Funded by the Natural Sciences and Engineering Research Council of Canada

  5. Correlation between structural and magnetic properties of half-metallic spinel CuV2S4 due to the order-disorder transition of 3d2(t2g) orbitals of V3+ ions

    International Nuclear Information System (INIS)

    Kumara, L.S.R.; Tokiwa, N.; Awaka, J.; Hagino, T.; Nagata, S.; Park, Young Jun; Hidaka, M.

    2008-01-01

    Structural and magnetic properties of the spinel CuV 2 S 4 have been studied by means of X-ray diffraction using synchrotron radiation and measurements of magnetic susceptibility. The structural phase transitions occur at about 55 K and 90 K, and the superlattice reflections (h±q o , k±q o , l) having an orthorhombic reduced wavevector q o =(1/4,1/4,0) are observed at 10 K. This suggests that the structure below 55 K is a commensurate unit cell of 4a p x 4b p x c p , where the subscript 'p' means a pseudo-spinel structure, and that the structural phase transitions are induced by the cooperative displacement of S ions in one-dimensional VS 6 octahedral chains, which are aligned along an orthorhombic[110] direction. The susceptibility also shows that the weak ferromagnetic transition occurs at about 90 K, and the spike-like susceptibility is observed in the region of about 40 K and 55 K. The unusual electronic and magnetic properties of CuV 2 S 4 in the low-temperature phases below about 90 K are interpreted by order and disorder states of (3d xy , 3d yz , 3d zx ) for the V 3+ 3d 2 (t 2g ) orbitals in the VS 6 octahedral chains. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Simultaneous acquisition for T2 -T2 Exchange and T1 -T2 correlation NMR experiments

    Science.gov (United States)

    Montrazi, Elton T.; Lucas-Oliveira, Everton; Araujo-Ferreira, Arthur G.; Barsi-Andreeta, Mariane; Bonagamba, Tito J.

    2018-04-01

    The NMR measurements of longitudinal and transverse relaxation times and its multidimensional correlations provide useful information about molecular dynamics. However, these experiments are very time-consuming, and many researchers proposed faster experiments to reduce this issue. This paper presents a new way to simultaneously perform T2 -T2 Exchange and T1 -T2 correlation experiments by taking the advantage of the storage time and the two steps phase cycling used for running the relaxation exchange experiment. The data corresponding to each step is either summed or subtracted to produce the T2 -T2 and T1 -T2 data, enhancing the information obtained while maintaining the experiment duration. Comparing the results from this technique with traditional NMR experiments it was possible to validate the method.

  7. The role of diffusion weighted magnetic resonance imaging in ...

    African Journals Online (AJOL)

    Aim of the work: To demonstrate the role of Diffusion Weighted Imaging and ADC maps in assessing normal progression of the infantile brain myelination. Patients and methods: The present work included 30 infants with normal MRI study of the brain, normal psychomotor development and normal neurological examination.

  8. The role of diffusion weighted magnetic resonance imaging in ...

    African Journals Online (AJOL)

    Shaimaa R.A. Fadeel

    2015-06-16

    Jun 16, 2015 ... diffusion-weighted images and the measurement of the apparent diffusion coefficient (ADC) have been applied to the study of normal .... time msec/echo time msec); section thickness, 5 mm; intersec- tion gap, 2.5 mm; field of view, 20 cm; ..... 11. Forbes KP, Pipe JG, Bird CR. Changes in brain water diffusion.

  9. Effects of the Inertia Barbell Training on Lumbar Muscle T2 relaxation time.

    Science.gov (United States)

    Sun, Ming-Yun; Lu, Jian-Qiang; Ma, Zu-Chang; Lu, Jiao-Jiao; Huang, Qing; Sun, Yi-Ning; Liu, Yu

    2017-04-25

    The purpose of this study was to investigate variations in T2 relaxation time in normal human lumbar muscles caused by inertia barbell training. Thirty undergraduate healthy males (mean age=19 ± 1.2 years, weight=72 ± 10.0 kilograms, height=1.78 ± 0.1 meters) were recruited to participate in this study. Subjects were randomly assigned into 2 groups: an inertia barbell training group (IBTG) (n=15) and a normal barbell-training group (NBTG) (n=15). All subjects participated in lumbar flexion and extension muscle strength training for 1 hour per time, 3 times per week for a total of 8 weeks. The lumbar of each participant was scanned before and after the experiment using a 3.0T superconductive magnetic resonance imaging system. The T2 values measured after intervention were significantly different compared to the T2 values measured before the experiment in both the IBTG and NBTG groups (pbarbell training.

  10. T2 mapping in patellar chondromalacia

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Santiago, Fernando, E-mail: ferusan12@gmail.com [Department of Radiology, Traumatology Hospital, University Hospital Virgen de las Nieves, Granada (Spain); Pozuelo Calvo, Rocío [Department of Rehabilitation and Physical therapy, Traumatology Hospital, University Hospital Virgen de las Nieves, Granada (Spain); Almansa López, Julio [Department of Physic, University Hospital Virgen de las Nieves, Granada (Spain); Guzmán Álvarez, Luis; Castellano García, María del Mar [Department of Radiology, Traumatology Hospital, University Hospital Virgen de las Nieves, Granada (Spain)

    2014-06-15

    Objective: To study the correlation between the T2 relaxation times of the patellar cartilage and morphological MRI findings of chondromalacia. Methods: This prospective study comprises 50 patients, 27 men and 23 women suffering of anterior knee pain (mean age: 29.7, SD 8.3 years; range: 16–45 years). MRI of 97 knees were performed in these patients at 1.5 T magnet including sagittal T1, coronal intermediate, axial intermediate fat sat and T2 mapping. Chondromalacia was assessed using a modified version of Noyes classification. The relaxation time, T2, was studied segmenting the full thickness of the patellar cartilage in 12 areas: 4 proximal (external facet–proximal–lateral (EPL), external facet–proximal–central (EPC), internal facet–proximal–central (IPC), internal facet–proximal–medial (IPM), 4 in the middle section (external facet–middle–lateral (EML), external facet–middle–central (EMC), internal facet–middle–central (IMC), internal facet–middle–medial (IMM) and 4 distal (external facet–distal–lateral (EDL), external facet–distal–central (EDC), internal facet–distal–central (IDC), internal facet–distal–medial (IDM). Results: T2 values showed a significant increase in mild chondromalacia regarding normal cartilage in most of the cartilage areas (p < 0.05), except in the internal distal facet (IDC and IDM), EPC, EDL, and IMM. Severe chondromalacia was characterized by a fall of T2 relaxation times with loss of statistical significant differences in comparison with normal cartilage, except in EMC and IMC, where similar values as mild chondromalacia were maintained (p < 0.05). Conclusions: Steepest increase in T2 values of patellar cartilage occurs in early stages of patellar cartilage degeneration. Progression of morphologic changes of chondromalacia to more severe degrees is associated to a new drop of T2 relaxation times approaching basal values in most of the areas of the patellar cartilage, except in the

  11. T2 shine-through phenomena in diffusion-weighted MR imaging of lumbar discs after oxygen-ozone discolysis: a randomized, double-blind trial with steroid and O2-O3 discolysis versus steroid only.

    Science.gov (United States)

    Perri, Marco; Grattacaso, Giuseppe; di Tunno, Valeria; Marsecano, Claudia; Gennarelli, Antonio; Michelini, Giulia; Splendiani, Alessandra; Di Cesare, Ernesto; Masciocchi, Carlo; Gallucci, Massimo

    2015-10-01

    To evaluate the discal morpho-structural changes as predictive sign in the clinical outcome after Ozone Therapy in lumbar disc herniation using the T2 shine-through effect in DWI. One hundred and fifty-four patients suffering from lumbosciatica (89 men and 65 women; range 23-62 years) were included in previous MR study performed with FSE-T2 and T2-fat, SE-T1 and DWI sequences and were randomly assigned to two groups. Seventy-seven patients (Control Group) underwent conservative treatment with intraforaminal injection of steroid and anesthetic. The remaining 77 patients (Study Group) underwent the same treatment with the addiction of oxygen-ozone (O2-O3). During the coming 6 months, an MRI follow-up with the same sequences was performed. An intervertebral disc volumetric analysis (IDVA), DWI signal score and post treatment clinical outcome evaluation were performed for an assessment of hernia reduction. χ (2) test, Student's t test and analysis of covariance were used for comparison of variables. In the Study Group, 58 over 77 patients had a successful outcome (Responders). In the Responders group, DWI T2 shine-through effect was present during MRI follow-up and in particular in 53 of 77 patients in the 6 months of follow-up (P discs' shrinkage in the sixth month of follow-up (P disc reduction and moreover could be considered as a predictive sign of response to oxygen-ozone treatment.

  12. T2K neutrino flux prediction

    CERN Document Server

    Abe, K.

    2013-01-02

    The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations using an off-axis muon neutrino beam with a peak energy of about 0.6 GeV that originates at the J-PARC accelerator facility. Interactions of the neutrinos are observed at near detectors placed at 280 m from the production target and at the far detector -- Super-Kamiokande (SK) -- located 295 km away. The flux prediction is an essential part of the successful prediction of neutrino interaction rates at the T2K detectors and is an important input to T2K neutrino oscillation and cross section measurements. A FLUKA and GEANT3 based simulation models the physical processes involved in the neutrino production, from the interaction of primary beam protons in the T2K target, to the decay of hadrons and muons that produce neutrinos. The simulation uses proton beam monitor measurements as inputs. The modeling of hadronic interactions is re-weighted using thin target hadron production data, including recent charged pion and kaon measurements from the NA...

  13. The role of dynamic contrast-enhanced and diffusion weighted magnetic resonance imaging in the female pelvis

    Energy Technology Data Exchange (ETDEWEB)

    Sala, Evis, E-mail: es220@radiol.cam.ac.uk [University Department of Radiology, Box 218, Level 5, Addenbrooke' s Hospital, Hills Road, Cambridge CB2 0QQ (United Kingdom); Rockall, Andrea, E-mail: Andrea.Rockall@bartsandthelondon.nhs.uk [Department of Radiology, St Bartholomew' s Hospital, West Smithfield, London EC1A 7ED (United Kingdom); Rangarajan, Deepa, E-mail: rdrangarajan@googlemail.com [Department of Radiology, Box 218, Addenbrooke' s Hospital, Hills Road, Cambridge CB2 0QQ (United Kingdom); Kubik-Huch, Rahel A., E-mail: rahel.kubik@ksb.ch [Institute of Radiology, Department of Medical Services, Kantonsspital Baden Im Ergel, CH-5404 Baden (Switzerland)

    2010-12-15

    Functional imaging by means of dynamic multiphase contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion weighted magnetic resonance imaging (DW-MRI) is now part of the standard imaging protocols for evaluation of the female pelvis. DCE-MRI and DW-MRI are important MR imaging techniques which enable the radiologist to move from morphological to functional assessment of diseases of the female pelvis. This is mainly due to the limitations of morphologic imaging, particularly in lesion characterization, accurate lymph node staging, assessment of tumour response and inability to differentiate post-treatment changes from tumour recurrence. DCE-MRI improves the accuracy of T2WI in staging of endometrial cancer. It also helps differentiate tumour recurrence from radiation fibrosis in patients with cervical cancer. DCE-MRI improves characterization of cystic adnexal lesions and detection of small peritoneal implants in patients with ovarian cancer. DW-MRI is valuable in preoperative staging of patients with endometrial and cervical cancer, especially in detection of extra-uterine disease. It does increase reader's confidence for detection of recurrent disease in gynaecological malignancies and improves detection of small peritoneal implants in patients with ovarian cancer. In this review article we give an overview of both DCE-MRI and DW-MRI techniques, concentrating on their main clinical application in the female pelvis, and present a practical approach of the added value of these techniques according to the main pathological conditions, highlighting the pearls and pitfalls of each technique.

  14. 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.

  15. Highlights from T2K

    Directory of Open Access Journals (Sweden)

    Hadley David

    2014-04-01

    Full Text Available T2K is a long baseline neutrino oscillation experiment. A high intensity proton beam at J-PARC produces a narrow-band muon-neutrino beam with a peak energy of 0.6 GeV at the far detector, Super-Kamiokande, 295km from the production point. The T2K experiment has observed electron neutrino appearance in a muon neutrino beam and measured sin22θ13 = 0.140−0.032+0.038 (0.170−0.037+0.045 assuming the normal (inverted hierarchy. In addition the latest measurements of θ23 and ∆m322 are reported, along with the latest T2K neutrino interaction cross section measurements of the inclusive CC, CCQE and NCE channels.

  16. Towards MRI T2 contrast agents of increased efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Branca, Marlène [CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse (France); Université de Toulouse, UPS, INPT, LCC, F-31077 Toulouse (France); Marciello, Marzia, E-mail: marziamarciello@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid (Spain); Ciuculescu-Pradines, Diana [CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse (France); Université de Toulouse, UPS, INPT, LCC, F-31077 Toulouse (France); Respaud, Marc [LPCNO, INSA, 135 Avenue de Rangueil, 31077 Toulouse Cedex 4 (France); Morales, Maria del Puerto [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049 Madrid (Spain); Serra, Raphael; Casanove, Marie-José [CNRS, CEMES (Centre d' Elaboration des Matériaux et d' Etudes Structurales) (France); Amiens, Catherine, E-mail: catherine.amiens@lcc-toulouse.fr [CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse (France); Université de Toulouse, UPS, INPT, LCC, F-31077 Toulouse (France)

    2015-03-01

    Magnetic nanoparticles can be efficient contrast agents for T2 weighted magnetic resonance imaging (MRI) after tuning of some key parameters such as size, surface state, colloidal stability and magnetization, thus motivating the development of new synthetic pathways. In this paper we report the effects of surface coating on the efficiency of two different types of iron based nanoparticles (NPs) as MRI contrast agents. Starting from well-defined hydrophobic iron oxide nanospheres and iron nanocubes of 13 nm size, we have used three methods to increase their hydrophilicity and transfer them into water: surface ligand modification, ligand exchange or encapsulation. The NPs obtained have been characterized by dynamic light scattering and transmission electron microscopy, and the relaxivities of their stable colloidal solutions in water have been determined. Among all samples prepared, iron nanocubes coated by silica display the highest relaxivity (r{sub 2}) value: 628 s{sup −1} mM{sup −1}. - Highlights: • Surface coating effect on the efficiency of iron based nanoparticles (NPs) as MRI contrast agents. • Synthesis of 2 different types of hydrophobic iron based NPs: iron oxide nanospheres and iron nanocubes (13 nm). • Development of three different procedures to stabilize iron based NPs in water. • Iron nanocubes coated by silica displayed the highest r{sub 2} value (628 s{sup −1} mM{sup −1})

  17. Magnetic resonance imaging of blood-brain barrier permeability in ischemic stroke using diffusion-weighted arterial spin labeling in rats.

    Science.gov (United States)

    Tiwari, Yash V; Lu, Jianfei; Shen, Qiang; Cerqueira, Bianca; Duong, Timothy Q

    2017-08-01

    Diffusion-weighted arterial spin labeling magnetic resonance imaging has recently been proposed to quantify the rate of water exchange (K w ) across the blood-brain barrier in humans. This study aimed to evaluate the blood-brain barrier disruption in transient (60 min) ischemic stroke using K w magnetic resonance imaging with cross-validation by dynamic contrast-enhanced magnetic resonance imaging and Evans blue histology in the same rats. The major findings were: (i) at 90 min after stroke (30 min after reperfusion), group K w magnetic resonance imaging data showed no significant blood-brain barrier permeability changes, although a few animals showed slightly abnormal K w . Dynamic contrast-enhanced magnetic resonance imaging confirmed this finding in the same animals. (ii) At two days after stroke, K w magnetic resonance imaging revealed significant blood-brain barrier disruption. Regions with abnormal K w showed substantial overlap with regions of hyperintense T 2 (vasogenic edema) and hyperperfusion. Dynamic contrast-enhanced magnetic resonance imaging and Evans blue histology confirmed these findings in the same animals. The K w values in the normal contralesional hemisphere and the ipsilesional ischemic core two days after stroke were: 363 ± 17 and 261 ± 18 min -1 , respectively (P < 0.05, n = 9). K w magnetic resonance imaging is sensitive to blood-brain barrier permeability changes in stroke, consistent with dynamic contrast-enhanced magnetic resonance imaging and Evans blue extravasation. K w magnetic resonance imaging offers advantages over existing techniques because contrast agent is not needed and repeated measurements can be made for longitudinal monitoring or averaging.

  18. T2* relaxometry mapping of the uterine zones

    International Nuclear Information System (INIS)

    Imaoka, Izumi; Nakatsuka, Takayuki; Araki, Tetsuro

    2012-01-01

    Background: Previous literature demonstrated that the T2* value of the uterine junctional zone was lower than that of peripheral myometrium by using BOLD MR imaging. We expect T2* mapping image may add more information to T2-weighted images of the uterine myometrium. Purpose: To evaluate whether T2* mapping software would reproduce the result of previous report, and to apply the software to benign uterine diseases. Material and Methods: Five healthy volunteers and 19 patients clinically suspected of having benign pelvic disease were imaged using a 1.5T MR system. All women were of reproductive age, and all provided informed consent. Sagittal T2* images using a multishot EPI sequence were obtained. T2* values were calculated and color T2* maps reconstructed using a T2* fitting tool. Results: The uterine zones could be identified in all 24 examinations on the T2* maps. In addition, a thin '4th zone' was seen between the endometrium and the JZ (junctional zone) in 19 of 24 examinations. The T2* value of JZ was significantly lower than that of peripheral myometrium (PM), (P < 0.001). No significant difference in the T2* value of the JZ or of PM was noted between normal uterus and uterus with leiomyomas and/or adenomyosis. Conclusion: A quantitative T2* map can easily be obtained using the PRIDE software T2* fitting tool, and the software reproduces the result from previous report. T2* value of the junctional zone was lower than that of peripheral myometrium regardless of having benign myometrial diseases.

  19. Diffusion-Weighted Magnetic Resonance Imaging in Rhombencephalitis due to Listeria monocytogenes

    Energy Technology Data Exchange (ETDEWEB)

    Hatipoglu, H.G.; Onbasioglu Gurbuz, M.; Sakman, B.; Yuksel, E. [Dept. of Radiology, Ankara Numune Education and Research Hospital, Ankara (Turkey)

    2007-04-15

    We present diffusion-weighted imaging findings of a case of rhombencephalitis due to Listeria monocytogenes. It is a rare, life-threatening disorder. The diagnosis is difficult by clinical findings only. In this report, we aim to draw attention to the role of conventional and diffusion-weighted magnetic resonance imaging findings. To our knowledge, this is the first case report in the literature with apparent diffusion coefficient values of diseased brain parenchyma.

  20. T2K and Beyond

    Directory of Open Access Journals (Sweden)

    M. G. Catanesi

    2016-01-01

    Full Text Available This paper presents the state of the art of the T2K experiment and the measurements prospects for the incoming years. After a brief description of the experiment, the most recent results will be illustrated. The observation of the electron neutrino appearance in a muon neutrino beam and the new high-precision measurements of the mixing angle θ13 by the reactor experiments have led to a reevaluation of the expected sensitivity to the oscillation parameters, relative to what was given in the original T2K proposal. For this reason the new physics potential of T2K for 7.8×1021 p.o.t. and for data exposure 3 times larger than that expected to be reachable with accelerator and beam line upgrades in 2026 before the start of operation of the next generation of long-baseline neutrino oscillation experiments will also be described in the text. In particular the last challenging scenario opens the door to the possibility of obtaining, under some conditions, a 3σ measurement excluding sin⁡(δCP=0.

  1. A voxel based comparative analysis using magnetization transfer imaging and T1-weighted magnetic resonance imaging in progressive supranuclear palsy

    Directory of Open Access Journals (Sweden)

    Mangalore Sandhya

    2014-01-01

    Full Text Available Aims: In progressive supranuclear palsy (PSP tissue damage occurs in specific cortical and subcortical regions. Voxel based analysis using T1-weighted images depict quantitative gray matter (GM atrophy changes. Magnetization transfer (MT imaging depicts qualitative changes in the brain parenchyma. The purpose of our study was to investigate whether MT imaging could indicate abnormalities in PSP. Settings and Design: A total of 10 patients with PSP (9 men and 1 woman and 8 controls (5 men and 3 women were studied with T1-weighted magnetic resonance imaging (MRI and 3DMT imaging. Voxel based analysis of T1-weighted MRI was performed to investigate brain atrophy while MT was used to study qualitative abnormalities in the brain tissue. We used SPM8 to investigate group differences (with two sample t-test using the GM and white matter (WM segmented data. Results: T1-weighted imaging and MT are equally sensitive to detect changes in GM and WM in PSP. Magnetization transfer ratio images and magnetization-prepared rapid acquisition of gradient echo revealed extensive bilateral volume and qualitative changes in the orbitofrontal, prefrontal cortex and limbic lobe and sub cortical GM. The prefrontal structures involved were the rectal gyrus, medial, inferior frontal gyrus (IFG and middle frontal gyrus (MFG. The anterior cingulate, cingulate gyrus and lingual gyrus of limbic lobe and subcortical structures such as caudate, thalamus, insula and claustrum were also involved. Cerebellar involvement mainly of anterior lobe was also noted. Conclusions: The findings suggest that voxel based MT imaging permits a whole brain unbiased investigation of central nervous system structural integrity in PSP.

  2. The Fontan circulation and the liver : A magnetic resonance diffusion-weighted imaging study

    NARCIS (Netherlands)

    Wolff, Djoeke; van Melle, Joost P.; Dijkstra, Hildebrand; Bartelds, Beatrijs; Willems, Tineke P.; Hillege, Hans; van den Berg, Aad P.; Ebels, Tjark; Sijens, Paul E.; Berger, Rolf M. F.

    2016-01-01

    Background: Patients with a Fontan circulation tend to develop liver fibrosis, liver cirrhosis and even hepatocellular carcinoma. The aim of this study is to use the magnetic resonance technique diffusing-weighted imaging (DWI) for detecting liver fibrosis/cirrhosis in Fontan patients and to

  3. Diagnosis of pericardial cysts using diffusion weighted magnetic resonance imaging: A case series

    Directory of Open Access Journals (Sweden)

    Mousavi Negareh

    2011-09-01

    Full Text Available Abstract Introduction Congenital pericardial cysts are benign lesions that arise from the pericardium during embryonic development. The diagnosis is based on typical imaging features, but atypical locations and signal magnetic resonance imaging sequences make it difficult to exclude other lesions. Diffusion-weighted magnetic resonance imaging is a novel method that can be used to differentiate tissues based on their restriction to proton diffusion. Its use in differentiating pericardial cysts from other pericardial lesions has not yet been described. Case presentation We present three cases (a 51-year-old Caucasian woman, a 66-year-old Caucasian woman and a 77-year-old Caucasian woman with pericardial cysts evaluated with diffusion-weighted imaging using cardiac magnetic resonance imaging. Each lesion demonstrated a high apparent diffusion coefficient similar to that of free water. Conclusion This case series is the first attempt to investigate the utility of diffusion-weighted magnetic resonance imaging in the assessment of pericardial cysts. Diffusion-weighted imaging may be a useful noninvasive diagnostic tool for pericardial cysts when conventional imaging findings are inconclusive.

  4. The Role of Diffusion-Weighted Magnetic Resonance Imaging in the ...

    African Journals Online (AJOL)

    2018-02-23

    Feb 23, 2018 ... How to cite this article: Aksoy S, Erdil I, Hocaoglu E, Inci E, Adas GT,. Kemik O, et al. The Role of Diffusion-Weighted Magnetic Resonance. Imaging in the Differential Diagnosis of Simple and Hydatid Cysts of the. Liver. Niger J Clin Pract 2018;21:212-6. This is an open access article distributed under the ...

  5. Tumor microvascular changes in antiangiogenic treatment : Assessment by magnetic resonance contrast media of different molecular weights

    NARCIS (Netherlands)

    Turetschek, K; Preda, A; Novikov, [No Value; Brasch, RC; Weinmann, HJ; Wunderbaldinger, P; Roberts, TPL

    Purpose: To test magnetic resonance (MR) contrast media of different molecular weights (MWs) for their potential to characterize noninvasively microvascular changes in an experimental tumor treatment model. Materials and Methods: MD-MBA-435, a poorly differentiated human breast cancer cell line, was

  6. Cerebral Effects of Targeted Temperature Management Methods Assessed by Diffusion-Weighted Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Grejs, Anders Morten; Gjedsted, Jakob; Pedersen, Michael

    2016-01-01

    The aim of this randomized porcine study was to compare surface targeted temperature management (TTM) to endovascular TTM evaluated by cerebral diffusion-weighted magnetic resonance imaging (MRI): apparent diffusion coefficient (ADC), and by intracerebral/intramuscular microdialysis. It is well...

  7. A diffusion-based method for long-T2suppression in steady state sequences: Validation and application for 3D-UTE imaging.

    Science.gov (United States)

    Soustelle, Lucas; Lamy, Julien; Rousseau, François; Armspach, Jean-Paul; Loureiro de Sousa, Paulo

    2017-12-19

    To introduce a novel method for long-T 2 signal physical suppression in steady-state based on configuration states combination and modulation using diffusion weighting. Its efficiency in yielding a high contrast in short-T 2 structures using an ultrashort echo time acquisition module (Diff-UTE) is compared to the adiabatically prepared Inversion-Recovery-UTE sequence (IR-UTE). Using a rectangular-pulse prepared 3D-UTE sequence, the possibility of long-T 2 component signal cancellation through diffusion effects is addressed, and the condition met for sets of sequence parameters. Simultaneously, the short-T 2 component signal is maximized using a Bloch equation-based optimization process. The method is evaluated from simulations, and experiments are conducted on a phantom composed of short and long-T 2 components, as well as on an ex vivo mouse head. Within equal scan times, the proposed method allowed for an efficient long-T 2 signal suppression, and expectedly yielded a higher signal to noise ratio in short-T 2 structures compared to the IR-UTE technique, although an intrinsic short-T 2 signal loss is expected through the preparation module. The Diff-UTE method represents an interesting alternative to the IR-UTE technique. Diffusion weighting allowing for a long-T 2 suppression results in a less penalizing method to generate a high and selective contrast in short-T 2 components. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  8. Measuring Restriction Sizes Using Diffusion Weighted Magnetic Resonance Imaging: A Review

    Directory of Open Access Journals (Sweden)

    Melanie Martin

    2013-01-01

    Full Text Available This article reviews a new concept in magnetic resonance as applied to cellular and biological systems. Diffusion weighted magnetic resonance imaging can be used to infer information about restriction sizes of samples being measured. The measurements rely on the apparent diffusion coefficient changing with diffusion times as measurements move from restricted to free diffusion regimes. Pulsed gradient spin echo (PGSE measurements are limited in the ability to shorten diffusion times and thus are limited in restriction sizes which can be probed. Oscillating gradient spin echo (OGSE measurements could provide shorter diffusion times so smaller restriction sizes could be probed.

  9. Experimental studies of confinement in the EXTRAP T2 and T2R reversed field pinches

    International Nuclear Information System (INIS)

    Cecconello, Marco

    2003-01-01

    The confinement properties of fusion plasmas are affected by magnetic and electrostatic fluctuations. The determination of the plasma confinement properties requires the measurement of several global and local quantities such as the ion and electron temperatures, the electron and neutral density profiles, the radiation emissivity profiles, the ohmic input power and the particle and heat diffusivities. The focus of this thesis is the study of the plasma confinement properties based on measurements of these quantities under different experimental conditions. The studies have been carried out on the reversed field pinch experiments EXTRAP T2 and T2R at the Alfven Laboratory, Royal Institute of Technology in Stockholm. Studies carried out in EXTRAP T2 were focused on dynamo activity and on the effect of phase alignment and locking to the wall of magnetic instabilities. These were observed with a dedicated imaging system. The experimental studies in EXTRAP T2R were focused on the measurement of the confinement properties of different configurations. To this aim, a set of diagnostics were used some of which were upgraded, such as the interferometer, while others were newly installed, such as a neutral particle energy analyser and a bolometer array. The dynamo, which is responsible for the plasma sustainment, involves resistive magnetohydrodynamic instabilities that enhance stochastic transport. Furthermore, the plasma confinement properties are in general improved in the presence of mode rotation. The possibility of reducing the stochastic transport and thereby further improving the confinement has been demonstrated in a current profile control experiment. These results indicate that long pulse operations with a resistive shell and current profile control are indeed feasible

  10. MRI UTE-T2* profile characteristics correlate to walking mechanics and patient reported outcomes 2 years after ACL reconstruction.

    Science.gov (United States)

    Williams, A A; Titchenal, M R; Andriacchi, T P; Chu, C R

    2018-04-01

    Quantitative magnetic resonance imaging (MRI) ultrashort echo time (UTE) T2* is sensitive to cartilage deep tissue matrix changes after anterior cruciate ligament reconstruction (ACLR). This study was performed to determine whether UTE-T2* profile analysis is a useful clinical metric for assessing cartilage matrix degeneration. This work tests the hypotheses that UTE-T2* depthwise rates of change (profile slopes) correlate with clinical outcome metrics of walking mechanics and patient reported outcomes (PRO) in patients 2 years after ACLR. Thirty-six patients 2 years after ACLR completed knee MRI, gait analysis, and PRO. UTE-T2* maps were generated from MRI images and depthwise UTE-T2* profiles were calculated for weight-bearing cartilage in the medial compartment. UTE-T2* profiles from 14 uninjured subjects provided reference values. UTE-T2* profile characteristics, including several different measures of profile slope, were tested for correlation to kinetic and kinematic measures of gait and also to PRO. Decreasing UTE-T2* profile slopes in ACLR knees moderately correlated with increasing knee adduction moments (r = 0.41, P profiles from both ACLR and contralateral knees of ACLR subjects differed from that of uninjured controls (P profile slopes reflect cartilage deep tissue collagen matrix disruption in a population at increased risk for knee osteoarthritis (OA). That UTE-T2* profiles were associated with mechanical and patient reported measures of clinical outcomes support further study into a potential mechanistic relationship between these factors and OA development. Copyright © 2018. Published by Elsevier Ltd.

  11. Diffusion-weighted magnetic resonance imaging reveals the effects of different cooling temperatures on the diffusion of water molecules and perfusion within human skeletal muscle

    International Nuclear Information System (INIS)

    Yanagisawa, O.; Fukubayashi, T.

    2010-01-01

    Aim: To evaluate the effect of local cooling on the diffusion of water molecules and perfusion within muscle at different cooling temperatures. Materials and methods: Magnetic resonance diffusion-weighted (DW) images of the leg (seven males) were obtained before and after 30 min cooling (0, 10, and 20 o C), and after a 30 min recovery period. Two types of apparent diffusion coefficient (ADC; ADC1, reflecting both water diffusion and perfusion within muscle, and ADC2, approximating the true water diffusion coefficient) of the ankle dorsiflexors were calculated from DW images. T2-weighted images were also obtained to calculate T2 values of the ankle dorsiflexors. The skin temperature was measured before, during, and after cooling. Results: Both ADC values significantly decreased after cooling under all cooling conditions; the rate of decrease depended on the cooling temperature used (ADC1: -36% at 0 o C, -27.8% at 10 o C, and -22.6% at 20 o C; ADC2: -26% at 0 o C, -21.1% at 10 o C, and -14.6% at 20 o C). These significant decreases were maintained during the recovery period. Conversely, the T2 value showed no significant changes. Under all cooling conditions, skin temperature significantly decreased during cooling; the rate of decrease depended on the cooling temperature used (-74.8% at 0 o C, -51.1% at 10 o C, and -26.8% at 20 o C). Decreased skin temperatures were not restored to pre-cooling values during the recovery period under any cooling conditions. Conclusion: Local cooling decreased the water diffusion and perfusion within muscle with decreased skin temperature; the rates of decrease depended on the cooling temperature used. These decreases were maintained for 30 min after cooling.

  12. 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.)

  13. 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.).

  14. Classification of coronary atherosclerotic plaques ex vivo with T1, T2, and ultrashort echo time CMR.

    Science.gov (United States)

    Károlyi, Mihály; Seifarth, Harald; Liew, Gary; Schlett, Christopher L; Maurovich-Horvat, Pál; Stolzmann, Paul; Dai, Guangping; Huang, Shuning; Goergen, Craig J; Nakano, Masataka; Otsuka, Fumiyuki; Virmani, Renu; Hoffmann, Udo; Sosnovik, David E

    2013-04-01

    This study sought to determine whether the classification of human coronary atherosclerotic plaques with T1, T2, and ultrashort echo time (UTE) cardiac magnetic resonance (CMR) would correlate well with atherosclerotic plaque classification by histology. CMR has been extensively used to classify carotid plaque, but its ability to characterize coronary plaque remains unknown. In addition, the detection of plaque calcification by CMR remains challenging. Here, we used T1, T2, and UTE CMR to evaluate atherosclerotic plaques in fixed post-mortem human coronary arteries. We hypothesized that the combination of T1, T2, and UTE CMR would allow both calcified and lipid-rich coronary plaques to be accurately detected. Twenty-eight plaques from human donor hearts with proven coronary artery disease were imaged at 9.4-T with a T1-weighted 3-dimensional fast low-angle shot (FLASH) sequence (250-μm resolution), a T2-weighted rapid acquisition with refocused echoes (RARE) sequence (in-plane resolution 0.156 mm), and an UTE sequence (300-μm resolution). Plaques showing selective hypointensity on T2-weighted CMR were classified as lipid-rich. Areas of hypointensity on the T1-weighted images, but not the UTE images, were classified as calcified. Hyperintensity on the T1-weighted and UTE images was classified as hemorrhage. Following CMR, histological characterization of the plaques was performed with a pentachrome stain and established American Heart Association criteria. CMR showed high sensitivity and specificity for the detection of calcification (100% and 90%, respectively) and lipid-rich necrotic cores (90% and 75%, respectively). Only 2 lipid-rich foci were missed by CMR, both of which were extremely small. Overall, CMR-based classification of plaque was in complete agreement with the histological classification in 22 of 28 cases (weighted κ = 0.6945, p classification of human coronary atherosclerotic plaque. Copyright © 2013 American College of Cardiology Foundation

  15. Improving CT-guided transthoracic biopsy of mediastinal lesions by diffusion-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Marcos Duarte; TyngI, Chiang Cheng; Bitencourt, Almir Galvao Vieira; Gross, Jefferson Luiz; Zurstrassen, Charles Edouard, E-mail: marcosduarte500@gmail.com [AC Camargo Cancer Center, Sao Paulo, SP (Brazil); Hochhegger, Bruno [Universidade Federal de Ciencias da Saude de Porto Alegre (UFCSPA), RS (Brazil). Dept. de Radiologia; Benveniste, Marcelo Felipe Kuperman; Odisio, Bruno Calazans [University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Marchiori, Edson [Universidade Federal do Rio de Janeiro (UFRJ), Petropolis, RJ (Brazil)

    2014-11-15

    Objectives: to evaluate the preliminary results obtained using diffusion-weighted magnetic resonance imaging and the apparent diffusion coefficient for planning computed tomography-guided biopsies of selected mediastinal lesions. Methods: eight patients with mediastinal lesions suspicious for malignancy were referred for computed tomography-guided biopsy. Diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient measurement were performed to assist in biopsy planning with diffusion/computed tomography fused images. We selected mediastinal lesions that could provide discordant diagnoses depending on the biopsy site, including large heterogeneous masses, lesions associated with lung atelectasis or consolidation, lesions involving large mediastinal vessels and lesions for which the results of biopsy using other methods and histopathological examination were divergent from the clinical and radiological suspicion. Results: in all cases, the biopsy needle was successfully directed to areas of higher signal intensity on diffusion weighted sequences and the lowest apparent diffusion coefficient within the lesion (mean, 0.8 [range, 0.6–1.1]610{sup -3} mm{sup 2}/s), suggesting high cellularity. All biopsies provided adequate material for specific histopathological diagnoses of four lymphomas, two sarcomas and two thymoma s. Conclusion: functional imaging tools, such as diffusion-weighted imaging and the apparent diffusion coefficient, are promising for implementation in noninvasive and imaging-guided procedures. However, additional studies are needed to confirm that mediastinal biopsy can be improved with these techniques. (author)

  16. T2 relaxometry of ring lesions of the brain

    International Nuclear Information System (INIS)

    Jayakumar, P.N.; Srikanth, S.G.; Chandrashekar, H.S.; Subbakrishna, D.K.

    2007-01-01

    Aim: To differentiate two common aetiologies of 'ring lesions,' tuberculomas and cysticercal cysts, using T2 relaxometry. Materials and methods: Fifty-five ring-enhancing lesions of the brain (32 cysticercal cysts; 23 tuberculomas) in 27 patients with focal seizures were studied for T2 relaxation times. Results: The mean T2 relaxation times of cysticercal cysts was 617 ms (range 305-1365 ms; SD 272.2) and that of tuberculomas 161 ms (range 83-290 ms; SD 60.3; 95% confidence). Conclusion: T2 relaxometry is a simple, reliable and valuable non-invasive magnetic resonance imaging (MRI) technique to differentiate between intracranial cysticercal cysts and tuberculomas, and may be incorporated in routine diagnostic protocols

  17. Metal Matrix Superconductor Composites for Flight-Weight Microwave Lightcraft Magnets

    International Nuclear Information System (INIS)

    Gross, Dan A.; Myrabo, Leik N.

    2008-01-01

    Flight-weight superconducting magnets are designed for a 20-m diameter MicroWave LightCraft (MWLC). The twin coil unit with storage capacity of 900 MJ, is made of structural carbon fiber filaments with a superconducting MgCNi 3 high current density film surface layer, imbedded in a beryllium stabilizer matrix of high electrical and thermal conductivity. These 'bucking' magnets run circumferentially about the lightcraft rim, and provide a 2-Tesla magnetic field necessary for the craft's hypersonic MHD slipstream accelerator. Each magnet is comprised of a single 22 cm diameter, hollow cylindrical cable made from metal matrix composites for superconductors (MMC lowbar Sc) with integral coolant passageways for circulating liquid-helium coolant to prevent the magnets from warming above the superconductive transition temperature. Each is suspended inside a 30-cm diameter toroidal vacuum tube, braced by a radial mesh of high-strength insulating fibers loaded in tension. For a coil separation distance of 1.4 m, each coil has a calculated mass of 1365 kg which is within 2x of the ultimate objective

  18. Aiming for a shorter rheumatoid arthritis MRI protocol: can contrast-enhanced MRI replace T2 for the detection of bone marrow oedema?

    Energy Technology Data Exchange (ETDEWEB)

    Stomp, Wouter; Bloem, Johan L.; Reijnierse, Monique [Leiden University Medical Center, Department of Radiology, P.O. Box 9600, Leiden (Netherlands); Krabben, Annemarie; Heijde, Desiree van der; Huizinga, Tom W.J.; Helm-van Mil, Annette H.M. van der [Leiden University Medical Center, Department of Rheumatology, P.O. Box 9600, Leiden (Netherlands)

    2014-10-15

    To determine whether T1 post-gadolinium chelate images (T1Gd) can replace T2-weighted images (T2) for evaluating bone marrow oedema (BME), thereby allowing a shorter magnetic resonance imaging (MRI) protocol in rheumatoid arthritis (RA). In 179 early arthritis patients and 43 advanced RA patients, wrist and metacarpophalangeal joints were examined on a 1.5-T extremity MRI system with a standard protocol (coronal T1, T2 fat-saturated and coronal and axial T1 fat-saturated after Gd). BME was scored according to OMERACT RAMRIS by two observers with and without T2 images available. Agreement was assessed using intraclass correlation coefficients (ICCs) for semi-quantitative scores and test characteristics with T2 images as reference. Agreement between scores based on T2 and T1Gd images was excellent ICC (0.80-0.99). At bone level, sensitivity and specificity of BME on T1Gd compared to T2 were high for both patient groups and both readers (all ≥80 %). T1Gd and T2 images are equally suitable for evaluating BME. Because contrast is usually administered to assess (teno)synovitis, a short MRI protocol of T1 and T1Gd is sufficient in RA. (orig.)

  19. Colorectal carcinoma: Ex vivo evaluation using 3-T high-spatial-resolution quantitative T2 mapping and its correlation with histopathologic findings.

    Science.gov (United States)

    Yamada, Ichiro; Yoshino, Norio; Hikishima, Keigo; Miyasaka, Naoyuki; Yamauchi, Shinichi; Uetake, Hiroyuki; Yasuno, Masamichi; Saida, Yukihisa; Tateishi, Ukihide; Kobayashi, Daisuke; Eishi, Yoshinobu

    2017-05-01

    In this study, we aimed to evaluate the feasibility of determining the mural invasion depths of colorectal carcinomas using high-spatial-resolution (HSR) quantitative T2 mapping on a 3-T magnetic resonance (MR) scanner. Twenty colorectal specimens containing adenocarcinomas were imaged on a 3-T MR system equipped with a 4-channel phased-array surface coil. HSR quantitative T2 maps were acquired using a spin-echo sequence with a repetition time/echo time of 7650/22.6-361.6ms (16 echoes), 87×43.5-mm field of view, 2-mm section thickness, 448×224 matrix, and average of 1. HSR fast-spin-echo T2-weighted images were also acquired. Differences between the T2 values (ms) of the tumor tissue, colorectal wall layers, and fibrosis were measured, and the MR images and histopathologic findings were compared. In all specimens (20/20, 100%), the HSR quantitative T2 maps clearly depicted an 8-layer normal colorectal wall in which the T2 values of each layer differed from those of the adjacent layer(s) (Pquantitative T2 maps and histopathologic data yielded the same findings regarding the tumor invasion depth. Our results indicate that 3-T HSR quantitative T2 mapping is useful for distinguishing colorectal wall layers and differentiating tumor and fibrotic tissues. Accordingly, this technique could be used to determine mural invasion by colorectal carcinomas with a high level of accuracy. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Diffusion tensor magnetic resonance imaging driven growth modeling for radiotherapy target definition in glioblastoma

    DEFF Research Database (Denmark)

    Jensen, Morten B; Guldberg, Trine L; Harbøll, Anja

    2017-01-01

    BACKGROUND: The clinical target volume (CTV) in radiotherapy is routinely based on gadolinium contrast enhanced T1 weighted (T1w + Gd) and T2 weighted fluid attenuated inversion recovery (T2w FLAIR) magnetic resonance imaging (MRI) sequences which have been shown to over- or underestimate...

  1. T 2 mapping of cerebrospinal fluid

    DEFF Research Database (Denmark)

    Spijkerman, Jolanda M; Petersen, Esben T; Hendrikse, Jeroen

    2018-01-01

    OBJECT: Cerebrospinal fluid (CSF) T 2 mapping can potentially be used to investigate CSF composition. A previously proposed CSF T 2-mapping method reported a T 2 difference between peripheral and ventricular CSF, and suggested that this reflected different CSF compositions. We studied...

  2. 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.)

  3. T2 shortening in childhood moyamoya disease

    International Nuclear Information System (INIS)

    Takanashi, J.; Sugita, K.; Tanabe, Y.; Ito, C.; Date, H.; Niimi, H.

    1996-01-01

    We examined T2 shortening in six children with infarcts due to moyamoya disease to clarify whether there are characteristic patterns of T2 shortening in the deep grey and white matter. Profound T2 shortening in the deep grey and white matter was observed in the acute stage of infarct in two cases, which changed to high intensity in the chronic stage; in this stage no T2 shortening was demonstrated in any case. Neither haemorrhagic infarction nor calcification was seen on CT or MRI. There could be longitudinally different T2 shortening patterns between infarcts due to moyamoya disease and other disorders. (orig.). With 2 figs., 1 tab

  4. Proton MR spectroscopic imaging of basal ganglia and thalamus in neurofibromatosis type 1: correlation with T2 hyperintensities

    Energy Technology Data Exchange (ETDEWEB)

    Barbier, Charlotte; Barantin, Laurent [CHRU and Tours University, Department of Neuroradiology, Tours (France); Chabernaud, Camille [CHRU and Tours University et INSERM U930, Department of Pediatric Neurology, Tours (France); Bertrand, Philippe [CHRU and Tours University, Department of Radiology, Tours (France); Sembely, Catherine; Sirinelli, Dominique [CHRU and Tours University, Department of Pediatric Radiology, Tours (France); Castelnau, Pierre [CHRU and Tours University et INSERM U930, Department of Pediatric Neurology, Tours (France); CHRU and Tours University et INSERM U930, Tours (France); Neurologie Pediatrique and INSERM U930, Hopital d' Enfants Gatien de Clocheville, Tours cedex 09 (France); Cottier, Jean-Philippe [CHRU and Tours University, Department of Neuroradiology, Tours (France); CHRU and Tours University et INSERM U930, Tours (France)

    2011-02-15

    Neurofibromatosis type 1 (NF1) is frequently associated with hyperintense lesions on T2-weighted images called ''unidentified bright objects'' (UBO). To better characterize the functional significance of UBO, we investigate the basal ganglia and thalamus using spectroscopic imaging in children with NF1 and compare the results to anomalies observed on T2-weighted images. Magnetic resonance (MR) data of 25 children with NF1 were analyzed. On the basis of T2-weighted images analysis, two groups were identified: one with normal MR imaging (UBO- group; n = 10) and one with UBO (UBO+ group; n = 15). Within the UBO+ group, a subpopulation of patients (n = 5) only had lesions of the basal ganglia. We analyzed herein seven regions of interest (ROIs) for each side: caudate nucleus, capsulo-lenticular region, lateral and posterior thalamus, thalamus (lateral and posterior voxels combined), putamen, and striatum. For each ROI, a spectrum of the metabolites and their ratio was obtained. Patients with abnormalities on T2-weighted images had significantly lower NAA/Cr, NAA/Cho, and NAA/mI ratios in the lateral right thalamus compared with patients with normal T2. These abnormal spectroscopic findings were not observed in capsulo-lenticular regions that had UBO but in the thalamus region that was devoid of UBO. Multivoxel spectroscopic imaging using short-time echo showed spectroscopic abnormalities in the right thalamus of NF1 patients harboring UBO, which were mainly located in the basal ganglia. This finding could reflect the anatomical and functional interactions of these regions. (orig.)

  5. Microstructural Investigation and MolecularWeight Determination of 1, 2-Polybutadiene by Nuclear Magnetic Resonance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Farshid Ziaee

    2013-01-01

    Full Text Available In this research, the microstructural of low molecular weight 1,2-polybutadiene (1,2-PBD was conducted by 1H and 13C nuclear magnetic resonance spectroscopy (NMR to determine the isomeric contents of 1,4-cis, 1,4-trans and 1,2-vinyl in 1,2-PBD polymer structures. Number average molecular weight for low molecular weight 1,2-PBD was measured by NMR techniques and the results were compared with gel permeation chromatography. Due to the presence of methyl end group and its comparison with repeating units in 1,2-PBD microstructure, the number average molecular weight was calculated by NMR techniques. For calculation of surface areas, carbon and protons of methyl groups were characterized using distortion enhancement by polarization transfer (DEPT methods. For proton assignment of methyl end groups in 1H NMR spectral analysis the heteronuclear multiple quantum coherence (HMQC method was employed. Finally, stereoregularity and tacticity of 1,2-PBD were investigated through pentad and heptad sequences splitting of olefinic methylene and methine carbons pendant groups with various NMR acquisition temperatures from 20 to 50oC. 13C NMR spectra showed that with increasing of NMR acquisition temperature, the number of split peaks of two olefinic carbons increased.

  6. Focal neuronal loss, reversible subcortical focal T2 hypointensity in seizures with a nonketotic hyperglycemic hyperosmolar state

    Energy Technology Data Exchange (ETDEWEB)

    Raghavendra, S.; Ashalatha, R.; Thomas, Sanjeev V. [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Neurology, Trivandrum, Kerala (India); Kesavadas, C. [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Imaging Sciences and Interventional Radiology, Trivandrum (India)

    2007-04-15

    Neuroimaging in seizures associated with nonketotic hyperglycemia (NKH) is considered normal. We report magnetic resonance imaging (MRI) abnormalities in four patients with NKH and seizures. We prospectively evaluated clinical and radiological abnormalities in four patients with NKH during the period March 2004 to December 2005. All patients presented with seizures, either simple or complex partial seizures or epilepsia partialis continua. Two of them had transient hemianopia. MRI showed subcortical T2 hypointensity in the occipital white matter and in or around the central sulcus (two patients each), T2 hyperintensity of the overlying cortex (two patients), focal overlying cortical enhancement (three patients) and bilateral striatal hyperintensity (one patient). Diffusion-weighted imaging (DWI) performed in three patients showed restricted diffusion. The ictal semiology and electroencephalographic (EEG) findings correlated with the MRI abnormalities. On clinical recovery, the subcortical T2 hypointensity and striatal hyperintensity reversed in all patients. The initial cortical change evolved to FLAIR hyperintensity suggestive of focal cortical gliosis. The radiological differential diagnosis considered initially included encephalitis, malignancy and hemorrhagic infarct rendering a diagnostic dilemma. We identified subcortical T2 hypointensity rather than hyperintensity as a characteristic feature of seizures associated with NKH. Only very few similar reports exist in literature. Reversible bilateral striatal T2 hyperintensity in NKH has not been reported to the best of our knowledge. (orig.)

  7. Focal neuronal loss, reversible subcortical focal T2 hypointensity in seizures with a nonketotic hyperglycemic hyperosmolar state.

    Science.gov (United States)

    Raghavendra, S; Ashalatha, R; Thomas, Sanjeev V; Kesavadas, C

    2007-04-01

    Neuroimaging in seizures associated with nonketotic hyperglycemia (NKH) is considered normal. We report magnetic resonance imaging (MRI) abnormalities in four patients with NKH and seizures. We prospectively evaluated clinical and radiological abnormalities in four patients with NKH during the period March 2004 to December 2005. All patients presented with seizures, either simple or complex partial seizures or epilepsia partialis continua. Two of them had transient hemianopia. MRI showed subcortical T2 hypointensity in the occipital white matter and in or around the central sulcus (two patients each), T2 hyperintensity of the overlying cortex (two patients), focal overlying cortical enhancement (three patients) and bilateral striatal hyperintensity (one patient). Diffusion-weighted imaging (DWI) performed in three patients showed restricted diffusion. The ictal semiology and electroencephalographic (EEG) findings correlated with the MRI abnormalities. On clinical recovery, the subcortical T2 hypointensity and striatal hyperintensity reversed in all patients. The initial cortical change evolved to FLAIR hyperintensity suggestive of focal cortical gliosis. The radiological differential diagnosis considered initially included encephalitis, malignancy and hemorrhagic infarct rendering a diagnostic dilemma. We identified subcortical T2 hypointensity rather than hyperintensity as a characteristic feature of seizures associated with NKH. Only very few similar reports exist in literature. Reversible bilateral striatal T2 hyperintensity in NKH has not been reported to the best of our knowledge.

  8. Clinical application of diffusion-weighted magnetic resonance imaging to intracranial disorders

    International Nuclear Information System (INIS)

    Yanaka, Kiyoyuki; Shirai, Shizuo; Kimura, Hiroshi; Kamezaki, Takao; Matsumura, Akira; Nose, Tadao.

    1995-01-01

    Diffusion-weighted magnetic resonance imaging was performed to determine the changes in water diffusion and to investigate the detectability of diffusion anisotropy in patients with intracranial disorders. Diffusion maps of the apparent diffusion coefficient (ADC) were created of 19 patients with cerebral infarction, five with intracerebral hematoma, four with glioma, four with meningioma, four with hydrocephalus, and five with subdural hematoma. ADC was increased in chronic cerebral infarction and glioma, and decreased in acute cerebral infarction, meningioma, and the marginal area of glioma compared with the ADC of the normal gray matter. There was a significant difference in ADC between the marginal and internal areas of glioma. Increased ADC may be due to increased vasogenic edema in infarction and a lack of significant restriction of diffusion within glioma. Decreased ADC can be attributed to restricted diffusion caused by cytotoxic edema in infarction and the underlying histological pattern of densely packed tumor cells in glioma. Diffusion anisotropy of the internal capsule was less detectable in pathological than normal hemispheres. Diffusion anisotropy was less detectable in patients with hydrocephalus and subdural hematoma. Intracranial lesions were thought to have influenced the compression of the brain structures and cells, resulting in decreased diffusion. The measurement of ADC by diffusion-weighted magnetic resonance imaging has the potential for greater understanding of the biophysical changes in various intracranial disorders, including correct diagnosis of cerebral infarction, and histological diagnosis of brain tumor. (author)

  9. Clinical application of diffusion-weighted magnetic resonance imaging to intracranial disorders

    Energy Technology Data Exchange (ETDEWEB)

    Yanaka, Kiyoyuki; Shirai, Shizuo; Kimura, Hiroshi [Soujinkai Hospital, Ibaraki (Japan); Kamezaki, Takao; Matsumura, Akira; Nose, Tadao

    1995-09-01

    Diffusion-weighted magnetic resonance imaging was performed to determine the changes in water diffusion and to investigate the detectability of diffusion anisotropy in patients with intracranial disorders. Diffusion maps of the apparent diffusion coefficient (ADC) were created of 19 patients with cerebral infarction, five with intracerebral hematoma, four with glioma, four with meningioma, four with hydrocephalus, and five with subdural hematoma. ADC was increased in chronic cerebral infarction and glioma, and decreased in acute cerebral infarction, meningioma, and the marginal area of glioma compared with the ADC of the normal gray matter. There was a significant difference in ADC between the marginal and internal areas of glioma. Increased ADC may be due to increased vasogenic edema in infarction and a lack of significant restriction of diffusion within glioma. Decreased ADC can be attributed to restricted diffusion caused by cytotoxic edema in infarction and the underlying histological pattern of densely packed tumor cells in glioma. Diffusion anisotropy of the internal capsule was less detectable in pathological than normal hemispheres. Diffusion anisotropy was less detectable in patients with hydrocephalus and subdural hematoma. Intracranial lesions were thought to have influenced the compression of the brain structures and cells, resulting in decreased diffusion. The measurement of ADC by diffusion-weighted magnetic resonance imaging has the potential for greater understanding of the biophysical changes in various intracranial disorders, including correct diagnosis of cerebral infarction, and histological diagnosis of brain tumor. (author).

  10. Comparison of MRI T2 Relaxation Changes of Knee Articular Cartilage before and after Running between Young and Old Amateur Athletes

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jang Gyu; Jeon, Chan Hong; Lee, Eun Hye [Dept. of Radiology, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon (Korea, Republic of); Lee, Jae Chul; Kim, Hyun Joo [Soonchunhyang University College of Medicine, Seoul Hospital, Seoul (Korea, Republic of); Han, Jong Kyu [Dept. of Radiology, Soonchunhyang University College of Medicine, Cheonan Hospital, Cheonan (Korea, Republic of); Kim, Yong Dai [Dept. of Statistics, College of Natural Sciences, Seoul National University, Seoul (Korea, Republic of)

    2012-09-15

    To compare changes in T2 relaxation on magnetic resonance (MR) images of knee articular cartilage in younger and older amateur athletes before and after running. By using a 3.0-T MR imager, quantitative T2 maps of weight-bearing femoral and tibial articular cartilages in 10 younger and 10 older amateur athletes were acquired before, immediately after, and 2 hours after 30 minutes of running. Changes in global cartilage T2 signals of the medial and lateral condyles of the femur and tibia and regional cartilage T2 signals in the medial condyles of femoral and tibia in response to exercise were compared between the two age groups. Changes in global cartilage T2 values after running did not differ significantly between the age groups. In terms of the depth variation, relatively higher T2 values in the older group than in the younger group were observed mainly in the superficial layers of the femoral and tibial cartilage (p < 0.05). Age-related cartilage changes may occur mainly in the superficial layer of cartilage where collagen matrix degeneration is primarily initiated. However, no trend is observed regarding a global T2 changes between the younger and older age groups in response to exercise.

  11. Magnetic resonance imaging of myoedema in neuromuscular diseases

    International Nuclear Information System (INIS)

    Schedel, H.; Vogel, T.; Lissner, J.; Reimers, C.C.

    1992-01-01

    Magnetic resonance imaging was done in 100 patients suffering from various generalized neuromuscular diseases. 30 (30%) showed higher signal intensities on T2-weighted images compared to T1-weighted images without contrast medium, indicating muscle edema. In inflammatory myopathies diffuse and severe muscle edema were found, whereas local and slight or moderate muscle edema were unspecific findings. In 10 patients also contrast enhanced T1-weighted images were done, showing no more sensitivity than T2-weighted images. In conclusion, we think that magnetic resonance imaging may contribute to differential diagnosis of neuromuscular diseases. (orig.) [de

  12. Susceptibility weighted imaging: a new tool in magnetic resonance imaging of stroke

    Energy Technology Data Exchange (ETDEWEB)

    Santhosh, K. [Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum (India); Kesavadas, C. [Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum (India)], E-mail: chandkesav@yahoo.com; Thomas, B.; Gupta, A.K.; Thamburaj, K.; Kapilamoorthy, T. Raman [Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum (India)

    2009-01-15

    Susceptibility weighted imaging (SWI) is a magnetic resonance (MR) technique that is exquisitely sensitive to paramagnetic substances, such as deoxygenated blood, blood products, iron, and calcium. This sequence allows detection of haemorrhage as early as 6 h and can reliably detect acute intracerebral parenchymal, as well as subarachnoid haemorrhage. It detects early haemorrhagic transformation within an infarct and provides insight into the cerebral haemodynamics following stroke. It helps in the diagnosis of cerebral venous thrombosis. It also has applications in the work-up of stroke patients. The sequence helps in detecting microbleeds in various conditions, such as vasculitis, cerebral autosomal dominant arteriopathy, subacute infarcts and leucoencephalopathy (CADASIL), amyloid angiopathy, and Binswanger's disease. The sequence also aids in the diagnosis of vascular malformations and perinatal cerebrovascular injuries. This review briefly illustrates the utility of this MR technique in various aspects of stroke diagnosis and management.

  13. Distinction of salvaged and infarcted myocardium within the ischaemic area-at-risk with T2 mapping

    DEFF Research Database (Denmark)

    Hammer-Hansen, Sophia; Ugander, Martin; Hsu, Li-Yueh

    2014-01-01

    AIM: Area-at-risk (AAR) measurements often rely on T2-weighted images, but subtle differences in T2 may be overlooked with this method. To determine the differences in oedema between salvaged and infarcted myocardium, we performed quantitative T2 mapping of the AAR. We also aimed to determine...... values from T2 maps and signal intensities on T2-weighted images were measured in the corresponding areas. RESULTS: At both imaging time points, the T2 of the salvaged myocardium was longer than of remote (66.0 ± 6.9 vs. 51.4 ± 3.5 ms, P

  14. Diffusion-weighted magnetic resonance imaging indicates the severity of acute pancreatitis.

    Science.gov (United States)

    de Freitas Tertulino, Franklin; Schraibman, Vladimir; Ardengh, José Celso; do Espírito-Santo, Danilo Cerqueira; Ajzen, Sergio Aron; Torrez, Franz Robert Apodaca; Lobo, Edson Jose; Szejnfeld, Jacob; Goldman, Suzan Menasce

    2015-02-01

    To test the use of diffusion-weighted magnetic resonance imaging (DW-MRI) to differentiate between different degrees of severity of acute pancreatitis (AP). Thirty-six patients who underwent DW-MRI and magnetic resonance cholangiopancreatography were divided into patients with mild AP (mAP, n = 15), patients with necrotizing AP (nAP, n = 8), and patients with a normal pancreas (nP, n = 15; controls). The pancreas was divided into head, body, and tail, and each segment was classified according to image features: pattern 1, normal; pattern 2, mild inflammation; and pattern 3, necrosis. Apparent diffusion coefficients (ADCs) were measured in each segment and correlated with clinical diagnoses. A total of 108 segments was assessed (three segments per patient). Segments classified as pattern 1 in the nP and mAP groups showed similar ADC values (P = 0.29). ADC values calculated for the pancreatic segments grouped according to the different image patterns (1-3) were significantly different (P < 0.001). Comparisons revealed significant differences in signal intensity between all three patterns (P < 0.05). DW-MRI was a compatible and safe image option to differentiate tissue image patterns in patients with mAP, nAP, and nP, mainly in those with contraindications to contrast-enhanced MRI (which is classically required for determining the presence of necrosis) or computed tomography. ADC measures allowed precise differentiation between patterns 1, 2, and 3.

  15. Ovarian adenofibromas and cystadenofibromas - Magnetic resonance imaging findings including diffusion-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Mayumi [Dept. of Radiology, Univ. of Tokushima, Tokushima (Japan)], e-mail: mayumi@clin.med.tokushima-u.ac.jp; Matsuzaki, Kenji; Harada, Masafumi [Dept. of Radiology, Univ. of Tokushima, Tokushima (Japan)

    2013-03-15

    Background: Ovarian adenofibromas (AF) and cystadenofibromas (CAF) belong to the surface epithelial-stromal tumors, and may appear as solid, or solid and cystic masses mimicking ovarian cancers. Purpose: To evaluate the capability of magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) measurement for the diagnosis of ovarian AF/CAF. Material and Methods: Magnetic resonance manifestations of 13 cases of ovarian AF/CAF were retrospectively evaluated. DWI was obtained in all 13 lesions, and mean ADC values in 11 lesions were compared with those in solid portions of 27 ovarian cancers. Results: Neither case with AF/CAF revealed high signal intensity on DWI, whereas all ovarian cancers showed high signal intensity on DWI. The ADC values in the solid portions of AF/CAF were significantly higher than those of ovarian cancers (P < 0.001). A cut-off value of 1.20 X 10{sup -3} mm{sup 2}/s for AF/CAF had a sensitivity of 82%, specificity of 93%, positive predictive value of 82%, and negative predictive value of 93%. Conclusion: DWI with ADC measurement may be helpful in differentiating AF/CAF from ovarian cancers.

  16. The application of in vivo diffusion weighted magnetic resonance imaging on intracranial disorders

    International Nuclear Information System (INIS)

    Ebisu, Toshihiko; Naruse, Shoji; Horikawa, Yoshiharu

    1991-01-01

    Diffusion weighted magnetic resonance (MR) images were obtained by using motion-probing gradient (MPG) pulses in one or three orthogonal directions in the following subjects: (1) phantom models; (2) Wistar rats with experimentally induced brain edema; (3) normal volunteers, and patients with brain tumor, brain edema or cerebral infarction. A one direction method was capable of defining diffusion anisotropy of myelinated axonal fibers in white matter. A three orthogonal gradients method was useful for demonstrating the difference in the diffusion coefficients in various diseases due to its larger total gradient strength. Faster diffusion was detected in white matter parallel to the direction of MPG; and slower diffusion was detected perpendicular to the direction of MPG because the myelin sheath restricted water diffusion. Brain tumor and vasogenic edema were shown as faster diffusion, while cytotoxic edema, cerebral ischemia, and infarction (at the subacute or early chronic stage) were shown as slower diffusion. Thus, diffusion weighted MR imaging seemed to be a useful approach to qualitative and dynamic analyses of intracranial diseases. (N.K.)

  17. Diffusion-weighted magnetic resonance imaging of symptomatic nerve root of patients with lumbar disk herniation

    International Nuclear Information System (INIS)

    Eguchi, Yawara; Ohtori, Seiji; Yamashita, Masaomi; Yamauchi, Kazuyo; Suzuki, Munetaka; Orita, Sumihisa; Kamoda, Hiroto; Arai, Gen; Ishikawa, Tetsuhiro; Miyagi, Masayuki; Ochiai, Nobuyasu; Kishida, Shunji; Inoue, Gen; Takahashi, Kazuhisa; Masuda, Yoshitada; Ochi, Shigehiro; Kikawa, Takashi; Toyone, Tomoaki; Takaso, Masashi; Aoki, Yasuchika

    2011-01-01

    Diffusion-weighted imaging (DWI) can provide valuable structural information that may be useful for evaluating pathological changes of the lumbar nerve root. Diffusion-weighted magnetic resonance (MR) neurography has recently been introduced as an alternative way to visualize nerves, but to date, quantitative DWI and MR neurography have not been applied to evaluate the pathology of lumbar nerve roots. Our purpose was to visualize lumbar nerve roots and to analyze their morphology by MR neurography, and to measure the apparent diffusion coefficient (ADC) of lumbar nerve roots compressed by herniated disks using 1.5-T MR imaging. Ten consecutive patients (median age, 48.0 and range, 20-72 years) with monoradicular symptoms caused by a lumbar herniated disk and 14 healthy volunteers were studied. Regions of interests were placed on the lumbar roots at dorsal root ganglia (DRG) and distal spinal nerves on DWI to quantify mean ADC values. The spinal nerve roots were also visualized by MR neurography. In the patients, mean ADC values were significantly greater in the compressed DRG and distal spinal nerves than in intact nerves. MR neurography also showed abnormalities such as nerve swelling at and below the compression in the symptomatic nerve root. Increased ADC values were considered to be because of edema and Wallerian degeneration of compressed nerve roots. DWI is a potential tool for analysis of the pathophysiology of lumbar nerve roots compressed by herniated disks. (orig.)

  18. Estimation of Low Concentration Magnetic Fluid Weight Density and Detection inside an Artificial Medium Using a Novel GMR Sensor

    Directory of Open Access Journals (Sweden)

    Chinthaka GOONERATNE

    2008-04-01

    Full Text Available Hyperthermia treatment has been gaining momentum in the past few years as a possible method to manage cancer. Cancer cells are different to normal cells in many ways including how they react to heat. Due to this difference it is possible for hyperthermia treatment to destroy cancer cells without harming the healthy normal cells surrounding the tumor. Magnetic particles injected into the body generate heat by hysteresis loss and temperature is increased when a time varying external magnetic field is applied. Successful treatment depends on how efficiently the heat is controlled. Thus, it is very important to estimate the magnetic fluid density in the body. Experimental apparatus designed for testing, numerical analysis, and results obtained by experimentation using a simple yet novel and minimally invasive needle type spin-valve giant magnetoresistance (SV-GMR sensor, to estimate low concentration magnetic fluid weight density and detection of magnetic fluid in a reference medium is reported.

  19. T2-prepared velocity selective labelling

    DEFF Research Database (Denmark)

    Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra M A

    2016-01-01

    BACKGROUND AND AIM: Disturbances in cerebral oxygenation saturation (SO2) have been linked to adverse outcome in adults, children, and neonates. In intensive care, the cerebral SO2 is increasingly being monitored by Near-InfraRed Spectroscopy (NIRS). Unfortunately NIRS has a limited penetration....... These two measures were compared to SO2 that was obtained by a single probe MR-compatible NIRS setup, and to cerebral blood flow and venous SO2 that were obtained by arterial spin labelling and T2-TRIR, respectively. RESULTS: SO2-T2-BIOS and SO2-NIRS had a mean bias of -4.0% (95% CI -21.3% to 13.3%). SvO2-T......2-BIOS correlated with SO2-NIRS (R(2)=0.41, p=0.002) and SvO2-T2-TRIR (R(2)=0.87, p=0.002). In addition, SO2-NIRS correlated with SvO2-T2-TRIR (R(2)=0.85, p=0.003) Frontal cerebral blood flow correlated with SO2-T2-BIOS (R(2)=0.21, p=0.04), but was not significant in relation to SO2-NIRS. DISCUSSION...

  20. Transient global amnesia: increased signal intensity in the right hippocampus on diffusion-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, M.; Sakamoto, S.; Ishii, K. [Division of Neuroimaging Research, Hyogo Institute for Aging Brain and Cognitive Disorders (Japan); Imamura, T.; Kazui, H.; Mori, E. [Division of Clinical Neurosciences, Hyogo Institute for Aging Brain and Cognitive Disorders, Hyogo (Japan)

    2002-03-01

    We report on a patient with pure transient global amnesia (TGA) whose magnetic resonance imaging (MRI) demonstrated a small region of increased signal intensity in the right hippocampus on diffusion-weighted imaging (DWI). DWI was sensitive and useful for evaluating the early stage of TGA and might help to explain the pathophysiology of TGA. (orig.)

  1. Transient global amnesia: increased signal intensity in the right hippocampus on diffusion-weighted magnetic resonance imaging

    International Nuclear Information System (INIS)

    Matsui, M.; Sakamoto, S.; Ishii, K.; Imamura, T.; Kazui, H.; Mori, E.

    2002-01-01

    We report on a patient with pure transient global amnesia (TGA) whose magnetic resonance imaging (MRI) demonstrated a small region of increased signal intensity in the right hippocampus on diffusion-weighted imaging (DWI). DWI was sensitive and useful for evaluating the early stage of TGA and might help to explain the pathophysiology of TGA. (orig.)

  2. An application of the weighted horizontal magnetic gradient to solar compact and eruptive events

    Science.gov (United States)

    Korsós, M. B.; Ruderman, Michael S.; Erdélyi, R.

    2018-01-01

    We propose to apply the weighted horizontal magnetic gradient (WGM), introduced in Korsós et al., 2015, for analysing the pre-flare and pre-CME behaviour and evolution of Active Regions (ARs) using the SDO/HMI-Debrecen Data catalogue. To demonstrate the power of investigative capabilities of the WGM method, in terms of flare and CME eruptions, we studied two typical ARs, namely, AR 12158 and AR 12192. The choice of ARs represent canonical cases. AR 12158 produced an X1.6 flare with fast "halo" CME (vlinear = 1267 kms-1) while in AR 12192 there occurred a range of powerful X-class eruptions, i.e. X1.1, X1.6, X3.1, X1.0, X2.0 and X2.0-class energetic flares, interestingly, none with an accompanying CME. The value itself and temporal variation of WGM is found to possess potentially important diagnostic information about the intensity of the expected flare class. Furthermore, we have also estimated the flare onset time from the relationship of duration of converging and diverging motions of the area-weighted barycenters of two subgroups of opposite magnetic polarities. This test turns out not only to provide information about the intensity of the expected flare-class and the flare onset time but may also indicate whether a flare will occur with/without fast CME. We have also found that, in the case when the negative polarity barycenter has moved around and the positive one "remained" at the same coordinates preceding eruption, the flare occurred with fast "halo" CME. Otherwise, when both the negative and the positive polarity barycenters have moved around, the AR produced flares without CME. If these properties found for the movement of the barycenters are generic pre-cursors of CME eruption (or lack of it), identifying them may serve as an excellent pre-condition for refining the forecast of the lift-off of CMEs.

  3. Monitoring ankylosing spondylitis therapy by dynamic contrast-enhanced and diffusion-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gaspersic, Natasa [University Medical Centre, Department of Rheumatology, Ljubljana (Slovenia); Sersa, Igor [Jozef Stefan Institute, Ljubljana (Slovenia); Jevtic, Vladimir [Medical Faculty, Department of Radiology, Ljubljana (Slovenia); Tomsic, Matija; Praprotnik, Sonja [University Medical Centre, Department of Rheumatology, Ljubljana (Slovenia)

    2008-02-15

    The effects of different therapies on enthesitis/osteitis in active ankylosing spondylitis (AS) were evaluated by magnetic resonance imaging (MRI). The aim was to assess the role of quantitative MRI in the evaluation of AS treatment efficacy. Thirty patients with active spondylitis or bilateral sacroilitis were selected and followed up for 1 year. Ten of the patients were treated only with non-steroidal anti-inflammatory drugs, 10 patients additionally received at baseline an intravenous pulse of glucocorticoids and 10 patients were treated with regular infusions of infliximab. Disease activity was measured according to clinical instruments and laboratory tests. For each patient, one selected inflamed lesion was followed from baseline through control visits quantitatively by diffusion-weighted imaging (DWI) measuring the apparent diffusion coefficient (ADC) and by dynamic contrast-enhanced imaging (DCEI) with evaluation of the enhancement factor (f{sub enh}) and enhancement gradient (g{sub enh}). Clinical and quantitative MRI parameters diminished significantly with regression of the inflammatory activity. The improvement in AS was most pronounced in patients treated with infliximab; after 12 months the ADC diminished from an average of 1.31 to 0.88 x 10{sup -3} mm{sup 2}/s, f{sub enh} from 1.85 to 0.60, and g{sub enh} from 3.09 to 1.40 %/s. Diffusion-weighted imaging and DCEI were shown to be effective in quantifying changes in inflammation in skeletal lesions during the treatment of AS, and could therefore be convenient for assessing treatment efficacy. To the best of our knowledge this is the first time DWI was used to evaluate the activity of skeletal inflammation in rheumatic diseases such as AS. (orig.)