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Sample records for resolution noncontrast mri

  1. Non-contrast MRI perfusion angiosome in diabetic feet.

    Science.gov (United States)

    Zheng, Jie; Hastings, Mary K; Muccigross, David; Fan, Zhaoyang; Gao, Fabao; Curci, John; Hildebolt, Charles F; Mueller, Michael J

    2015-01-01

    The purpose of this study is to develop a non-contrast magnetic resonance imaging (MRI) approach to evaluate skeletal muscle perfusion in the diabetic foot based on the concept of angiosomes of the foot. Five healthy volunteers and five participants with diabetes (HbA1c = 7.2 ± 1.8%) without a history of peripheral artery disease were examined. The non-contrast perfusion measurements were performed during a toe flexion challenge. Absolute perfusion maps were created and two regions (medial and lateral) on the maps were segmented based on angiosomes. Regional difference in the perfusion of foot muscle was readily visualized in the MRI perfusion angiosomes during the challenge. In the participants with diabetes, the perfusion during toe flexion challenge was significantly lower than in healthy volunteers (P feet. • Non-contrast MRI perfusion angiosome maps measure regional perfusion in foot muscles non-invasively. • Foot perfusion response to challenge is reduced in persons with diabetes. • MRI perfusion angiosome maps may help evaluation of regional foot muscle perfusion.

  2. Non-contrast MRI perfusion angiosome in diabetic feet

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    Zheng, Jie [Cardiovascular Imaging Lab, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Hastings, Mary K.; Mueller, Michael J. [Washington University School of Medicine, The Program in Physical Therapy, St. Louis, MO (United States); Muccigross, David; Hildebolt, Charles F. [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Fan, Zhaoyang [Cedars-Sinai Medical Center, Biomedical Imaging Research Institute, Los Angeles, CA (United States); Gao, Fabao [West China Hospital, Sichuan University, Department of Radiology, Chengdu (China); Curci, John [Washington University School of Medicine, The Department of Surgery, St. Louis, MO (United States)

    2015-01-15

    The purpose of this study is to develop a non-contrast magnetic resonance imaging (MRI) approach to evaluate skeletal muscle perfusion in the diabetic foot based on the concept of angiosomes of the foot. Five healthy volunteers and five participants with diabetes (HbA1c = 7.2 ± 1.8 %) without a history of peripheral artery disease were examined. The non-contrast perfusion measurements were performed during a toe flexion challenge. Absolute perfusion maps were created and two regions (medial and lateral) on the maps were segmented based on angiosomes. Regional difference in the perfusion of foot muscle was readily visualized in the MRI perfusion angiosomes during the challenge. In the participants with diabetes, the perfusion during toe flexion challenge was significantly lower than in healthy volunteers (P < 0.01). The average perfusion for the medial plantar region of the right foot was lower in subjects with diabetes (38 ± 9 ml/min/100 g) than in healthy subjects (93 ± 33 ml/min/100 g). Non-contrast MRI perfusion angiosome maps demonstrate the feasibility of determining regional perfusion in foot muscles during toe challenge and may facilitate evaluation of muscle perfusion in diabetic feet. (orig.)

  3. Rotator cuff tears noncontrast MRI compared to MR arthrography

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    Lee, Ji Hyun; Yoon, Young Cheol [Sungkyunkwan University, School of Medicine, Department of Radiology, Samsung Medical Center, Gangnam-gu, Seoul (Korea, Republic of); Jung, Jee Young [Chungang University School of Medicine, Department of Radiology, Chungang University Hospital, Seoul (Korea, Republic of); Yoo, Jae Chul [Sungkyunkwan University, School of Medicine, Department of Orthopedic Surgery, Samsung Medical Center, Seoul (Korea, Republic of)

    2015-12-15

    To compare the accuracy of indirect magnetic resonance arthrography and noncontrast magnetic resonance imaging for diagnosing rotator cuff tears. In total, 333 patients who underwent noncontrast magnetic resonance imaging or indirect magnetic resonance arthrography were included retrospectively. Two musculoskeletal radiologists evaluated the images for the presence of supraspinatus-infraspinatus and subscapularis tendon tears. The overall diagnostic performance was calculated using the arthroscopic findings as the reference standard. Statistical differences between the diagnostic performances of the two methods were analyzed. Ninety-six and 237 patients who underwent noncontrast magnetic resonance imaging and indirect magnetic resonance arthrography were assigned into groups A and B, respectively. Sensitivity for diagnosing articular-surface partial-thickness supraspinatus-infraspinatus tendon tear was slightly higher in group B than in group A. Statistical significance was confirmed by multivariate analysis using the generalized estimating equation (p = 0.046). The specificity for diagnosing subscapularis tendon tear (85 % vs. 68 %, p = 0.012) and grading accuracy (57 % vs. 40 %, p = 0.005) was higher in group B than in group A; the differences were statistically significant for one out of two readers. Univariate analysis using the generalized estimating equation showed that the accuracy for diagnosing subscapularis tendon tear in group B was higher than in group A (p = 0.042). There were no statistically significant differences between the diagnostic performances of both methods for any other parameters. Indirect magnetic resonance arthrography may facilitate more accurate diagnosis and grading of subscapularis tendon tears compared with noncontrast magnetic resonance imaging. (orig.)

  4. The diagnostic performance of non-contrast 3-Tesla magnetic resonance imaging (3-T MRI) versus 1.5-Tesla magnetic resonance arthrography (1.5-T MRA) in femoro-acetabular impingement.

    Science.gov (United States)

    Crespo-Rodríguez, Ana M; De Lucas-Villarrubia, Jose C; Pastrana-Ledesma, Miguel; Hualde-Juvera, Ana; Méndez-Alonso, Santiago; Padron, Mario

    2017-03-01

    The aim of this study was to evaluate the diagnostic accuracy of 3-T non-contrast MRI versus 1.5-T MRA for assessing labrum and articular cartilage lesions in patients with clinical suspicion of femoro-acetabular impingement (FAI). Fifty patients (thirty men and twenty women, mean age 42.5 years) underwent 1.5-T MRA, 3-T MRI and arthroscopy on the same hip. An optimized high-resolution proton density spin echo pulse sequence was included in the 3-T non-contrast MRI protocol. The 3-T non-contrast MRI identified forty-two of the forty-three arthroscopically proven tears at the labral-chondral transitional zone (sensitivity, 97.7%; specificity, 100%; positive predictive value (PPV), 100%; negative predictive value (NPV), 87.5%; accuracy 98%). With 1.5-T MRA, forty-four tears were diagnosed. However, there was one false positive (sensitivity, 100%; specificity, 85.7%; PPV, 97.7%; NPV, 100%; accuracy 98%). Agreement between arthroscopy and MRI, whether 3-T non-contrast MRI or 1.5-T MRA, as to the degree of chondral lesion in the acetabulum was reached in half of the patients and in the femur in 76% of patients. Non-invasive assessment of the hip is possible with 3-T MR magnet. 3-T non-contrast MRI could replace MRA as the workhorse technique for assessing hip internal damage. MRA would then be reserved for young adults with a strong clinical suspicion of FAI but normal findings on 3-T non-contrast MRI. When compared with 1.5-T MRA, optimized sequences with 3-T non-contrast MRI help in detecting normal variants and in diagnosing articular cartilage lesions. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  5. Non-contrast 3D black blood MRI for abdominal aortic aneurysm surveillance: comparison with CT angiography

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    Zhu, Chengcheng; Leach, Joseph R.; Hope, Michael D. [University of California San Francisco, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Tian, Bing; Liu, Qi; Lu, Jianping; Chen, Luguang [Changhai Hospital, Department of Radiology, Shanghai (China); Saloner, David [University of California San Francisco, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Radiology Service, VA Medical Center, San Francisco, CA (United States)

    2017-05-15

    Management of abdominal aortic aneurysms (AAAs) is based on diameter. CT angiography (CTA) is commonly used, but requires radiation and iodinated contrast. Non-contrast MRI is an appealing alternative that may allow better characterization of intraluminal thrombus (ILT). This study aims to 1) validate non-contrast MRI for measuring AAA diameter, and 2) to assess ILT with CTA and MRI. 28 patients with AAAs (diameter 50.7 ± 12.3 mm) underwent CTA and non-contrast MRI. MRI was acquired at 3 T using 1) a conventional 3D gradient echo (GRE) sequence and 2) a 3D T{sub 1}-weighted black blood fast-spin-echo sequence. Two radiologists independently measured the AAA diameter. The ratio of signal of ILT and adjacent psoas muscle (ILT{sub r} = signal{sub ILT}/signal{sub Muscle}) was quantified. Strong agreement between CTA and non-contrast MRI was shown for AAA diameter (intra-class coefficient > 0.99). Both approaches had excellent inter-observer reproducibility (ICC > 0.99). ILT appeared homogenous on CTA, whereas MRI revealed compositional variations. Patients with AAAs ≥5.5 cm and <5.5 cm had a variety of distributions of old/fresh ILT types. Non-contrast 3D black blood MRI provides accurate and reproducible AAA diameter measurements as validated by CTA. It also provides unique information about ILT composition, which may be linked with elevated risk for disease progression. (orig.)

  6. Superior Abdominal 4D Flow MRI Data Consistency with Adjusted Preprocessing Workflow and Noncontrast Acquisitions.

    Science.gov (United States)

    Keller, Eric J; Collins, Jeremy D; Rigsby, Cynthia; Carr, James C; Markl, Michael; Schnell, Susanne

    2017-03-01

    To assess the impact of an alternative preprocessing workflow on noncontrast- and contrast-enhanced abdominal four-dimensional flow magnetic resonance imaging (4D flow MRI) data consistency. Twenty patients with cirrhosis and portal hypertension (5 women; 53 ± 10 years old) underwent 4D flow MRI at 3.0T before and after administration of 0.03 mmol/kg of gadofosveset trisodium with velocity sensitivities of 100 and 50 cm/s for arterial and venous flow quantifications, respectively. 4D flow MRI data were preprocessed using the conventional workflow (workflow 1), applying noise filters prior to eddy current correction, and an alternative workflow (workflow 2), first correcting for eddy currents and using noise filtering only if needed for anti-aliasing. Vessel segmentation quality was ranked by independent reviewers and compared via Wilcoxon signed-rank tests. Flow quantification and conservation of mass at two portal and one arterial branch points were compared via paired t tests. Segmentation quality was significantly higher for workflow 2 (P Workflow 2 resulted in larger flow values (P  0.05). Noncontrast acquisitions yielded significantly smaller portal flow values (P < 0.05) with improved conservation of mass (5.8 ± 4.7% vs. 8.7 ± 6.9%, P = 0.05 [portal]; 6.2 ± 4.5% vs. 13.7 ± 10.2%, P = 0.03 [arterial]). Superior abdominal 4D flow MRI data consistency was obtained by applying eddy current correction before any other data manipulation, using noise masking and velocity anti-aliasing cautiously, and using noncontrast acquisitions. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  7. Automatic segmentation of meningioma from non-contrasted brain MRI integrating fuzzy clustering and region growing

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    Liao Chun-Chih

    2011-08-01

    Full Text Available Abstract Background In recent years, magnetic resonance imaging (MRI has become important in brain tumor diagnosis. Using this modality, physicians can locate specific pathologies by analyzing differences in tissue character presented in different types of MR images. This paper uses an algorithm integrating fuzzy-c-mean (FCM and region growing techniques for automated tumor image segmentation from patients with menigioma. Only non-contrasted T1 and T2 -weighted MR images are included in the analysis. The study's aims are to correctly locate tumors in the images, and to detect those situated in the midline position of the brain. Methods The study used non-contrasted T1- and T2-weighted MR images from 29 patients with menigioma. After FCM clustering, 32 groups of images from each patient group were put through the region-growing procedure for pixels aggregation. Later, using knowledge-based information, the system selected tumor-containing images from these groups and merged them into one tumor image. An alternative semi-supervised method was added at this stage for comparison with the automatic method. Finally, the tumor image was optimized by a morphology operator. Results from automatic segmentation were compared to the "ground truth" (GT on a pixel level. Overall data were then evaluated using a quantified system. Results The quantified parameters, including the "percent match" (PM and "correlation ratio" (CR, suggested a high match between GT and the present study's system, as well as a fair level of correspondence. The results were compatible with those from other related studies. The system successfully detected all of the tumors situated at the midline of brain. Six cases failed in the automatic group. One also failed in the semi-supervised alternative. The remaining five cases presented noticeable edema inside the brain. In the 23 successful cases, the PM and CR values in the two groups were highly related. Conclusions Results indicated

  8. Feasibility study of myocardial perfusion and oxygenation by noncontrast MRI: comparison with PET study in a canine model.

    Science.gov (United States)

    McCommis, Kyle S; Zhang, Haosen; Herrero, Pilar; Gropler, Robert J; Zheng, Jie

    2008-01-01

    The purpose of this study was to examine the feasibility of quantifying myocardial blood flow (MBF) and rate of myocardial oxygen consumption (MVO(2)) during pharmacologically induced stress without using a contrast agent. The former was measured by the arterial spin labeling (ASL) method and the latter was obtained by measuring the oxygen extraction fraction (OEF) with the magnetic resonance imaging (MRI) blood oxygenation level-dependent effect and Fick's law. The MRI results were compared with the established positron emission tomography (PET) methods. Six mongrel dogs with induced acute moderate left coronary artery stenosis were scanned using a clinical PET and a 1.5-T MRI system, in the same day. Regional MBF, myocardial OEF and MVO(2) were measured with both imaging modalities. Correlation coefficients (R(2)) of the three myocardial indexes (MBF, OEF and MVO(2)) between MRI and PET methods ranged from 0.70 to 0.93. Bland-Altman statistics demonstrated that the estimated precision of the limits of agreement between MRI and PET measurements varied from 18% (OEF) to 37% (MBF) and 45% (MVO(2)). The detected changes in these indexes, at rest and during dobutamine stress, were similar between two image modalities. The proposed noncontrast MRI technique is a promising method to quantitatively assess myocardial perfusion and oxygenation.

  9. High Spatiotemporal Resolution Prostate MRI

    Science.gov (United States)

    2017-09-01

    AWARD NUMBER: W81XWH-15-1-0341 TITLE: High Spatiotemporal Resolution Prostate MRI PRINCIPAL INVESTIGATOR: Stephen J. Riederer, Ph.D...Resolution Prostate MRI 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-15-1-0341 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Stephen J. Riederer E-Mail...overall purpose of this project is to develop improved means using MRI for detecting prostate cancer with the potential for differentiating disease

  10. A comparison of non-contrast and contrast-enhanced MRI in the initial stage of Legg-Calve-Perthes disease

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    Kim, Harry K.W. [Texas Scottish Rite Hospital for Children, Center of Excellence in Hip Disorders, Dallas, TX (United States); University of Texas Southwestern, Department of Orthopedic Surgery, Dallas, TX (United States); Kaste, Sue [St. Jude Children' s Research Hospital, Department of Radiological Sciences, Memphis, TN (United States); St. Jude Children' s Research Hospital, Department of Oncology, Memphis, TN (United States); University of Tennessee School of Health Sciences, Department of Radiology, Memphis, TN (United States); Dempsey, Molly; Wilkes, David [Texas Scottish Rite Hospital for Children, Department of Radiology, Dallas, TX (United States)

    2013-09-15

    A prognostic indicator of outcome for Legg-Calve-Perthes disease (LCP) is needed to guide treatment decisions during the initial stage of the disease (stage 1), before deformity occurs. Radiographic prognosticators are applicable only after fragmentation (stage II). We investigated pre- and postcontrast MRI in depicting stage I femoral head involvement. Thirty children with stage I LCP underwent non-contrast coronal T1 fast spin-echo (FSE) and corresponding postcontrast fat-suppressed T1-weighted fast spin-echo (FSE) sequences to quantify the extent of femoral head involvement. Three pediatric radiologists and one pediatric orthopedic surgeon independently measured central head involvement. Interobserver reliability of percent head involvement using non-contrasted MR images had intraclass correlation coefficient (ICC) of 0.72. Postcontrast MRI improved interobserver reliability (ICC 0.82). Qualitatively, the area of involvement was more clearly visible on contrast-enhanced MRI. A comparison of results obtained by each observer using the two MRI techniques showed no correlation. ICC ranged from -0.08 to 0.03 for each observer. Generally, greater head involvement was depicted by contrast compared with non-contrast MRI (Pearson r = -0.37, P = 0.04). Pre- and postcontrast MRI assess two different components of stage I LCP. However, contrast-enhanced MRI more clearly depicts the area of involvement. (orig.)

  11. Cost-effectiveness analysis of a non-contrast screening MRI protocol for vestibular schwannoma in patients with asymmetric sensorineural hearing loss

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    Crowson, Matthew G.; Rocke, Daniel J.; Kaylie, David M. [Duke University Medical Center, Division of Otolaryngology-Head and Neck Surgery, Durham, NC (United States); Hoang, Jenny K. [Duke University Medical Center, Department of Radiology, Durham, NC (United States); Weissman, Jane L. [Oregon Health Sciences University, Professor Emerita of Diagnostic Radiology, Portland, OR (United States)

    2017-08-15

    We aimed to determine if a non-contrast screening MRI is cost-effective compared to a full MRI protocol with contrast for the evaluation of vestibular schwannomas. A decision tree was constructed to evaluate full MRI and screening MRI strategies for patients with asymmetric sensorineural hearing loss. If a patient were to have a positive screening MRI, s/he received a full MRI. Vestibular schwannoma prevalence, MRI specificity and sensitivity, and gadolinium anaphylaxis incidence were obtained through literature review. Institutional charge data were obtained using representative patient cohorts. One-way and probabilistic sensitivity analyses were completed to determine CE model threshold points for MRI performance characteristics and charges. The mean charge for a full MRI with contrast was significantly higher than a screening MRI ($4089 ± 1086 versus $2872 ± 741; p < 0.05). The screening MRI protocol was more cost-effective than a full MRI protocol with a willingness-to-pay from $0 to 20,000 USD. Sensitivity analyses determined that the screening protocol dominated when the screening MRI charge was less than $4678, and the imaging specificity exceeded 78.2%. The screening MRI protocol also dominated when vestibular schwannoma prevalence was varied between 0 and 1000 in 10,000 people. A screening MRI protocol is more cost-effective than a full MRI with contrast in the diagnostic evaluation of a vestibular schwannoma. A screening MRI likely also confers benefits of shorter exam time and no contrast use. Further investigation is needed to confirm the relative performance of screening protocols for vestibular schwannomas. (orig.)

  12. Preliminary comparison of normalized T1 and non-contrast perfusion MRI assessments of regional lung disease in cystic fibrosis patients.

    Science.gov (United States)

    Donnola, Shannon B; Dasenbrook, Elliott C; Weaver, David; Lu, Lan; Gupta, Karishma; Prabhakaran, Anjali; Yu, Xin; Chmiel, James F; McBennett, Kimberly; Konstan, Michael W; Drumm, Mitchell L; Flask, Chris A

    2017-03-01

    Previous studies have shown that Magnetic Resonance Imaging (MRI) techniques can be used to non-invasively assess lung disease in CF patients. In this study, we compare the sensitivity of normalized T1 (nT1) and non-contrast perfusion MRI techniques to detect regional lung disease in CF patients. MRI data were obtained for eight adult CF patients without overt pulmonary exacerbation (FEV1=45-127%) and six healthy volunteers on a Siemens Espree 1.5T MRI scanner. Sagittal nT1 and perfusion data were acquired for each subject's left and right lungs. A region-of-interest analysis was used to calculate mean nT1 and perfusion values in the individual lobes of the left and right lungs for each subject. In comparison to healthy controls, CF subjects showed a significant decrease in nT1 values in the upper lobe of the left lung as well as in the upper and anterior lobes of the right lung (pmethods were able to detect regional lung disease, the additional nT1 reductions in the CF patients suggests that nT1 may be more sensitive to regional CF lung disease. Copyright © 2015 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  13. “Wait and scan” management of patients with vestibular schwannoma and the relevance of non-contrast MRI in the follow-up

    Directory of Open Access Journals (Sweden)

    Jing Zou

    2017-12-01

    Full Text Available Vestibular schwannoma (VS is a slow-growing benign neoplasm. There has been an evolution in the management of VS from active treatments (microsurgery and stereotactic radiotherapy to conservative management (wait and scan. Regular MRI scanning is necessary to monitor tumor progression. Conservative management causes significantly less complications and offers a higher quality of life compared with active treatments. The mean growth rate of VS varies from 0.4 to 2.9 mm/year, and spontaneous shrinkage is observed in 3.8 percent of tumors during observation. If significant growth occurs, active treatment is considered. Significant growth is defined as an increase of at least 3 mm in the largest extrameatal diameter in any plane between the first and last available scans. The vestibulocochlear nerve is surrounded by cerebrospinal fluid, which provides natural contrast for MRI; thus, gadolinium may not be needed to detect VS. Specific sequences have high sensitivity, specificity, and accuracy for detection of progression. Hypointense signal in the ipsilateral inner ear fluid might be a useful sign to distinguish VS from meningioma. In this paper, we summarize the current status of research on conservative management and non-contrast MRI for the detection of VS.

  14. High Spatiotemporal Resolution Prostate MRI

    Science.gov (United States)

    2016-09-01

    which mimics the male pelvis for MR imaging (Figure 2). We started with a plastic shell of the male pelvis which corresponds to a male with BMI...balloons filled with 50 ml of differing B-gel solutions as shown in (A). These balloons were then positioned within the overall plastic shell while...EA, Froemming AT, Grimm RC, Kawashima A, Trzasko JD, “Prostate DCE-MRI: improved SNR with 32-element receiver arrays.” Annual Mtg Europ Cong Radiol

  15. Noncontrast skeletal muscle oximetry.

    Science.gov (United States)

    Zheng, Jie; An, Hongyu; Coggan, Andrew R; Zhang, Xiaodong; Bashir, Adil; Muccigrosso, David; Peterson, Linda R; Gropler, Robert J

    2014-01-01

    The objective of this study was to develop a new noncontrast method to directly quantify regional skeletal muscle oxygenation. The feasibility of the method was examined in five healthy volunteers using a 3 T clinical MRI scanner, at rest and during a sustained isometric contraction. The perfusion of skeletal muscle of the calf was measured using an arterial spin labeling method, whereas the oxygen extraction fraction of the muscle was measured using a susceptibility-based MRI technique. In all volunteers, the perfusion in soleus muscle increased significantly from 6.5 ± 2.0 mL (100 g min)(-1) at rest to 47.9 ± 7.7 mL (100 g min)(-1) during exercise (P oxygen extraction fraction did not change significantly, the rate of oxygen consumption increased from 0.43 ± 0.13 to 4.2 ± 1.5 mL (100 g min)(-1) (P muscle but with greater oxygen extraction fraction increase than the soleus muscle. This is the first MR oximetry developed for quantification of regional skeletal muscle oxygenation. A broad range of medical conditions could benefit from these techniques, including cardiology, gerontology, kinesiology, and physical therapy. Copyright © 2013 Wiley Periodicals, Inc.

  16. Standard high-resolution pelvic MRI vs. low-resolution pelvic MRI in the evaluation of deep infiltrating endometriosis

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    Scardapane, Arnaldo; Lorusso, Filomenamila; Ferrante, Annunziata; Stabile Ianora, Amato Antonio; Angelelli, Giuseppe [University Hospital ' ' Policlinico' ' of Bari, Interdisciplinary Department of Medicine, Bari (Italy); Scioscia, Marco [Sacro Cuore Don Calabria General Hospital, Department of Obstetrics and Gynecology, Negrar, Verona (Italy)

    2014-10-15

    To compare the capabilities of standard pelvic MRI with low-resolution pelvic MRI using fast breath-hold sequences to evaluate deep infiltrating endometriosis (DIE). Sixty-eight consecutive women with suspected DIE were studied with pelvic MRI. A double-acquisition protocol was carried out in each case. High-resolution (HR)-MRI consisted of axial, sagittal, and coronal TSE T2W images, axial TSE T1W, and axial THRIVE. Low-resolution (LR)-MRI was acquired using fast single shot (SSH) T2 and T1 images. Two radiologists with 10 and 2 years of experience reviewed HR and LR images in two separate sessions. The presence of endometriotic lesions of the uterosacral ligament (USL), rectovaginal septum (RVS), pouch of Douglas (POD), and rectal wall was noted. The accuracies of LR-MRI and HR-MRI were compared with the laparoscopic and histopathological findings. Average acquisition times were 24 minutes for HR-MRI and 7 minutes for LR-MRI. The more experienced radiologist achieved higher accuracy with both HR-MRI and LR-MRI. The values of sensitivity, specificity, PPV, NPV, and accuracy did not significantly change between HR and LR images or interobserver agreement for all of the considered anatomic sites. LR-MRI performs as well as HR-MRI and is a valuable tool for the detection of deep endometriosis extension. (orig.)

  17. Microvascular brain pathology on high resolution MRI

    NARCIS (Netherlands)

    Veluw, S.J. van

    2015-01-01

    Cerebral small vessel disease (SVD) is a common finding in the aging human brain and is associated with stroke, cognitive decline, and dementia. On autopsy, SVD encompasses pathological processes affecting small arteries and arterioles. Magnetic resonance imaging (MRI) detects the consequences of

  18. Utility of Noncontrast Magnetic Resonance Imaging for Detection of Recurrent Vestibular Schwannoma.

    Science.gov (United States)

    Williams, Jamie C; Carr, Carrie M; Eckel, Laurence J; Kotsenas, Amy L; Hunt, Christopher H; Carlson, Matthew L; Lane, John I

    2018-01-16

    Gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI) (T1WI) is the conventional imaging technique of choice to detect vestibular schwannoma (VS) recurrence or regrowth, despite suboptimal specificity secondary to enhancing postoperative changes. Furthermore, recent concerns regarding the accumulation of gadolinium in body tissues have led for a call to reduce the number of contrast-enhanced examinations. The objective of the current study is to evaluate the diagnostic accuracy of high-resolution noncontrast (three-dimensional [3D] T2) MRI relative to gadolinium-enhanced T1WI in the detection of VS recurrence after resection. Following Institutional Review Board approval, 13 consecutive postoperative patients with VS recurrence or regrowth were identified from a prospectively maintained clinical database in which recurrence was determined by progression on serial postoperative MRI examination. Three blinded neuroradiologists retrospectively evaluated a total of 41 postoperative MRI examinations from these patients using only gadolinium-enhanced T1WI and 3D T2 MRI for recurrence or regrowth. Interobserver agreement, differences in detection between the two sequences, and the sensitivity and specificity of 3D T2 MRI were assessed. Fifteen of the 41 postoperative MRIs demonstrated progression, as determined by examiner consensus on the gadolinium-enhanced T1WI. Agreement, measured using Krippendorff's alpha, was 0.82 for the 3D T2 images and 0.83 for the contrast-enhanced T1WI. All the three examiners demonstrated no difference in the detection of progression between the two sequences (McNemar's test p values 0.69 for examiner 1, 0.63 for examiner 2, and 0.99 for examiner 3). The sensitivity of 3D T2 was 0.78 (CI 0.60-0.96), while the specificity was 0.94 (CI 0.86-1.00). Noncontrast high-resolution 3D T2 MRI seems sufficient to assess for recurrence or regrowth after VS resection. The results of this study have implications for reducing cost, time, and

  19. High temporal resolution functional MRI using parallel echo volumar imaging

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    Rabrait, C.; Ciuciu, P.; Ribes, A.; Poupon, C.; Dehaine-Lambertz, G.; LeBihan, D.; Lethimonnier, F. [CEA Saclay, DSV, I2BM, Neurospin, F-91191 Gif Sur Yvette (France); Le Roux, P. [GEHC, Buc (France); Dehaine-Lambertz, G. [Unite INSERM 562, Gif Sur Yvette (France)

    2008-07-01

    Purpose: To combine parallel imaging with 3D single-shot acquisition (echo volumar imaging, EVI) in order to acquire high temporal resolution volumar functional MRI (fMRI) data. Materials and Methods: An improved EVI sequence was associated with parallel acquisition and field of view reduction in order to acquire a large brain volume in 200 msec. Temporal stability and functional sensitivity were increased through optimization of all imaging parameters and Tikhonov regularization of parallel reconstruction. Two human volunteers were scanned with parallel EVI in a 1.5 T whole-body MR system, while submitted to a slow event-related auditory paradigm. Results: Thanks to parallel acquisition, the EVI volumes display a low level of geometric distortions and signal losses. After removal of low-frequency drifts and physiological artifacts,activations were detected in the temporal lobes of both volunteers and voxel-wise hemodynamic response functions (HRF) could be computed. On these HRF different habituation behaviors in response to sentence repetition could be identified. Conclusion: This work demonstrates the feasibility of high temporal resolution 3D fMRI with parallel EVI. Combined with advanced estimation tools,this acquisition method should prove useful to measure neural activity timing differences or study the nonlinearities and non-stationarities of the BOLD response. (authors)

  20. STUDY OF POSTERIOR FOSSA TUMORS BY HIGH RESOLUTION MRI

    Directory of Open Access Journals (Sweden)

    Sree Hari

    2016-01-01

    Full Text Available INTRODUCTION Magnetic Resonance Imaging (MRI is the imaging modality used for the assessment of infratentorial neoplasms. Although Computed Tomography (CT provides better demonstration of small or subtle calcifications within tumors. OBJECTIVES Study is done to assess the potential of MRI in characterisation of different tumors in posterior fossa by evaluating various unenhanced and gadolinium enhanced sequences and to compare high resolution FSE MRI sequences with routine FSE MRI sequences in diagnosing posterior fossa brain tumors. Also correlate findings on Magnetic Resonance Imaging with Pathological diagnosis. MATERIALS AND METHODS A total of 52 patients were diagnosed by CT brain as having posterior fossa brain for a year of 2 years were included in the study. In all studies MR imaging was performed with a clinical 1.5 T system (General electrical medical systems. A dedicated phased-array coil was used. RESULTS The age group ranged from 1 year to 60 years, majority were between 1 to 20 years (39%. Slight male preponderance was seen (males 29, females 23. Commonest tumor encountered in our study was vestibular schwannoma. DWI alone can differentiate different pediatric posterior fossa brain tumors. One case of pilocytic astrocytoma showed solid lesion instead of typical cystic lesion with mural nodule. One case AT-RT showed 2 lesions one in cerebrum, one in CP angle. Common feature being intra-axial lesion involving cerebellum. MRI was able to predict diagnosis in 50 of the 52 tumors. CONCLUSION Magnetic Resonance Imaging was found to be a highly sensitive imaging procedure and method of choice for posterior fossa brain tumors.

  1. High resolution, MRI-based, segmented, computerized head phantom

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    Zubal, I.G.; Harrell, C.R.; Smith, E.O.; Smith, A.L.; Krischlunas, P. [Yale Univ., New Haven, CT (United States). Dept. of Diagnostic Radiology

    1999-01-01

    The authors have created a high-resolution software phantom of the human brain which is applicable to voxel-based radiation transport calculations yielding nuclear medicine simulated images and/or internal dose estimates. A software head phantom was created from 124 transverse MRI images of a healthy normal individual. The transverse T2 slices, recorded in a 256x256 matrix from a GE Signa 2 scanner, have isotropic voxel dimensions of 1.5 mm and were manually segmented by the clinical staff. Each voxel of the phantom contains one of 62 index numbers designating anatomical, neurological, and taxonomical structures. The result is stored as a 256x256x128 byte array. Internal volumes compare favorably to those described in the ICRP Reference Man. The computerized array represents a high resolution model of a typical human brain and serves as a voxel-based anthropomorphic head phantom suitable for computer-based modeling and simulation calculations. It offers an improved realism over previous mathematically described software brain phantoms, and creates a reference standard for comparing results of newly emerging voxel-based computations. Such voxel-based computations lead the way to developing diagnostic and dosimetry calculations which can utilize patient-specific diagnostic images. However, such individualized approaches lack fast, automatic segmentation schemes for routine use; therefore, the high resolution, typical head geometry gives the most realistic patient model currently available.

  2. Convex gradient optimization for increased spatiotemporal resolution and improved accuracy in phase contrast MRI.

    Science.gov (United States)

    Middione, Matthew J; Wu, Holden H; Ennis, Daniel B

    2014-12-01

    To evaluate convex gradient optimization (CVX) for increased spatiotemporal resolution and improved accuracy for phase-contrast MRI (PC-MRI). A conventional flow-compensated and flow-encoded (FCFE) PC-MRI sequence was compared with a CVX PC-MRI sequence using numerical simulations, flow phantom experiments, and in vivo experiments. Flow measurements within the ascending aorta, main pulmonary artery, and right/left pulmonary arteries of normal volunteers (N = 10) were acquired at 3T and analyzed using a conventional FCFE sequence and a CVX sequence with either higher spatial resolution or higher temporal resolution. All sequences mitigated chemical shift-induced phase errors and used equivalent breath-hold durations. Chemical shift-optimized PC-MRI has increased sequence efficiency when using CVX, which can provide either higher spatial or higher temporal resolution compared with conventional FCFE PC-MRI. Numerical simulations, flow phantom experiments, and in vivo experiments indicate that CVX measurements of total flow and peak velocity are increased and more accurate when compared with FCFE. CVX PC-MRI increases sequence efficiency while reducing chemical shift-induced phase errors. This can be used to provide either higher spatial or higher temporal resolution than conventional chemical shift-mitigated PC-MRI methods to provide more accurate measurements of blood flow and peak velocity. © 2013 Wiley Periodicals, Inc.

  3. Improved automatic optic nerve radius estimation from high resolution MRI

    Science.gov (United States)

    Harrigan, Robert L.; Smith, Alex K.; Mawn, Louise A.; Smith, Seth A.; Landman, Bennett A.

    2017-02-01

    The optic nerve (ON) is a vital structure in the human visual system and transports all visual information from the retina to the cortex for higher order processing. Due to the lack of redundancy in the visual pathway, measures of ON damage have been shown to correlate well with visual deficits. These measures are typically taken at an arbitrary anatomically defined point along the nerve and do not characterize changes along the length of the ON. We propose a fully automated, three-dimensionally consistent technique building upon a previous independent slice-wise technique to estimate the radius of the ON and surrounding cerebrospinal fluid (CSF) on high-resolution heavily T2-weighted isotropic MRI. We show that by constraining results to be three-dimensionally consistent this technique produces more anatomically viable results. We compare this technique with the previously published slice-wise technique using a short-term reproducibility data set, 10 subjects, follow-up <1 month, and show that the new method is more reproducible in the center of the ON. The center of the ON contains the most accurate imaging because it lacks confounders such as motion and frontal lobe interference. Long-term reproducibility, 5 subjects, follow-up of approximately 11 months, is also investigated with this new technique and shown to be similar to short-term reproducibility, indicating that the ON does not change substantially within 11 months. The increased accuracy of this new technique provides increased power when searching for anatomical changes in ON size amongst patient populations.

  4. Breast density estimation from high spectral and spatial resolution MRI

    Science.gov (United States)

    Li, Hui; Weiss, William A.; Medved, Milica; Abe, Hiroyuki; Newstead, Gillian M.; Karczmar, Gregory S.; Giger, Maryellen L.

    2016-01-01

    Abstract. A three-dimensional breast density estimation method is presented for high spectral and spatial resolution (HiSS) MR imaging. Twenty-two patients were recruited (under an Institutional Review Board--approved Health Insurance Portability and Accountability Act-compliant protocol) for high-risk breast cancer screening. Each patient received standard-of-care clinical digital x-ray mammograms and MR scans, as well as HiSS scans. The algorithm for breast density estimation includes breast mask generating, breast skin removal, and breast percentage density calculation. The inter- and intra-user variabilities of the HiSS-based density estimation were determined using correlation analysis and limits of agreement. Correlation analysis was also performed between the HiSS-based density estimation and radiologists’ breast imaging-reporting and data system (BI-RADS) density ratings. A correlation coefficient of 0.91 (pdensity estimations. An interclass correlation coefficient of 0.99 (pdensity estimations. A moderate correlation coefficient of 0.55 (p=0.0076) was observed between HiSS-based breast density estimations and radiologists’ BI-RADS. In summary, an objective density estimation method using HiSS spectral data from breast MRI was developed. The high reproducibility with low inter- and low intra-user variabilities shown in this preliminary study suggest that such a HiSS-based density metric may be potentially beneficial in programs requiring breast density such as in breast cancer risk assessment and monitoring effects of therapy. PMID:28042590

  5. Analysis strategies for high-resolution UHF-fMRI data.

    Science.gov (United States)

    Polimeni, Jonathan R; Renvall, Ville; Zaretskaya, Natalia; Fischl, Bruce

    2017-04-29

    Functional MRI (fMRI) benefits from both increased sensitivity and specificity with increasing magnetic field strength, making it a key application for Ultra-High Field (UHF) MRI scanners. Most UHF-fMRI studies utilize the dramatic increases in sensitivity and specificity to acquire high-resolution data reaching sub-millimeter scales, which enable new classes of experiments to probe the functional organization of the human brain. This review article surveys advanced data analysis strategies developed for high-resolution fMRI at UHF. These include strategies designed to mitigate distortion and artifacts associated with higher fields in ways that attempt to preserve spatial resolution of the fMRI data, as well as recently introduced analysis techniques that are enabled by these extremely high-resolution data. Particular focus is placed on anatomically-informed analyses, including cortical surface-based analysis, which are powerful techniques that can guide each step of the analysis from preprocessing to statistical analysis to interpretation and visualization. New intracortical analysis techniques for laminar and columnar fMRI are also reviewed and discussed. Prospects for single-subject individualized analyses are also presented and discussed. Altogether, there are both specific challenges and opportunities presented by UHF-fMRI, and the use of proper analysis strategies can help these valuable data reach their full potential. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. A new method for joint susceptibility artefact correction and super-resolution for dMRI

    Science.gov (United States)

    Ruthotto, Lars; Mohammadi, Siawoosh; Weiskopf, Nikolaus

    2014-03-01

    Diffusion magnetic resonance imaging (dMRI) has become increasingly relevant in clinical research and neuroscience. It is commonly carried out using the ultra-fast MRI acquisition technique Echo-Planar Imaging (EPI). While offering crucial reduction of acquisition times, two limitations of EPI are distortions due to varying magnetic susceptibilities of the object being imaged and its limited spatial resolution. In the recent years progress has been made both for susceptibility artefact correction and increasing of spatial resolution using image processing and reconstruction methods. However, so far, the interplay between both problems has not been studied and super-resolution techniques could only be applied along one axis, the slice-select direction, limiting the potential gain in spatial resolution. In this work we describe a new method for joint susceptibility artefact correction and super-resolution in EPI-MRI that can be used to increase resolution in all three spatial dimensions and in particular increase in-plane resolutions. The key idea is to reconstruct a distortion-free, high-resolution image from a number of low-resolution EPI data that are deformed in different directions. Numerical results on dMRI data of a human brain indicate that this technique has the potential to provide for the first time in-vivo dMRI at mesoscopic spatial resolution (i.e. 500μm) a spatial resolution that could bridge the gap between white-matter information from ex-vivo histology (≍1μm) and in-vivo dMRI (≍2000μm).

  7. Can increased spatial resolution solve the crossing fiber problem for diffusion MRI?

    Science.gov (United States)

    Schilling, Kurt; Gao, Yurui; Janve, Vaibhav; Stepniewska, Iwona; Landman, Bennett A; Anderson, Adam W

    2017-09-15

    It is now widely recognized that voxels with crossing fibers or complex geometrical configurations present a challenge for diffusion MRI (dMRI) reconstruction and fiber tracking, as well as microstructural modeling of brain tissues. This "crossing fiber" problem has been estimated to affect anywhere from 30% to as many as 90% of white matter voxels, and it is often assumed that increasing spatial resolution will decrease the prevalence of voxels containing multiple fiber populations. The aim of this study is to estimate the extent of the crossing fiber problem as we progressively increase the spatial resolution, with the goal of determining whether it is possible to mitigate this problem with higher resolution spatial sampling. This is accomplished using ex vivo MRI data of the macaque brain, followed by histological analysis of the same specimen to validate these measurements, as well as to extend this analysis to resolutions not yet achievable in practice with MRI. In both dMRI and histology, we find unexpected results: the prevalence of crossing fibers increases as we increase spatial resolution. The problem of crossing fibers appears to be a fundamental limitation of dMRI associated with the complexity of brain tissue, rather than a technical problem that can be overcome with advances such as higher fields and stronger gradients. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Rapid non-contrast magnetic resonance imaging for post appendectomy intra-abdominal abscess in children

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Megan H. [Washington University School of Medicine in St. Louis, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Eutsler, Eric P.; Khanna, Geetika [Washington University School of Medicine in St. Louis, Pediatric Radiology, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Sheybani, Elizabeth F. [Mercy Hospital St. Louis, Department of Radiology, St. Louis, MO (United States)

    2017-07-15

    Acute appendicitis, especially if perforated at presentation, is often complicated by postoperative abscess formation. The detection of a postoperative abscess relies primarily on imaging. This has traditionally been done with contrast-enhanced computed tomography. Non-contrast magnetic resonance imaging (MRI) has the potential to accurately detect intra-abdominal abscesses, especially with the use of diffusion-weighted imaging (DWI). To evaluate our single-center experience with a rapid non-contrast MRI protocol evaluating post-appendectomy abscesses in children with persistent postsurgical symptoms. In this retrospective, institutional review board-approved study, all patients underwent a clinically indicated non-contrast 1.5- or 3-Tesla abdomen/pelvis MRI consisting of single-shot fast spin echo, inversion recovery and DWI sequences. All MRI studies were reviewed by two blinded pediatric radiologists to identify the presence of a drainable fluid collection. Each fluid collection was further characterized as accessible or not accessible for percutaneous or transrectal drainage. Imaging findings were compared to clinical outcome. Seven of the 15 patients had a clinically significant fluid collection, and 5 of these patients were treated with percutaneous drain placement or exploratory laparotomy. The other patients had a phlegmon or a clinically insignificant fluid collection and were discharged home within 48 h. Rapid non-contrast MRI utilizing fluid-sensitive and DWI sequences can be used to identify drainable fluid collections in post-appendectomy patients. This protocol can be used to triage patients between conservative management vs. abscess drainage without oral/intravenous contrast or exposure to ionizing radiation. (orig.)

  9. Ultra-high field upper extremity peripheral nerve and non-contrast enhanced vascular imaging.

    Directory of Open Access Journals (Sweden)

    Shailesh B Raval

    Full Text Available The purpose of this study was to explore the efficacy of Ultra-high field [UHF] 7 Tesla [T] MRI as compared to 3T MRI in non-contrast enhanced [nCE] imaging of structural anatomy in the elbow, forearm, and hand [upper extremity].A wide range of sequences including T1 weighted [T1] volumetric interpolate breath-hold exam [VIBE], T2 weighted [T2] double-echo steady state [DESS], susceptibility weighted imaging [SWI], time-of-flight [TOF], diffusion tensor imaging [DTI], and diffusion spectrum imaging [DSI] were optimized and incorporated with a radiofrequency [RF] coil system composed of a transverse electromagnetic [TEM] transmit coil combined with an 8-channel receive-only array for 7T upper extremity [UE] imaging. In addition, Siemens optimized protocol/sequences were used on a 3T scanner and the resulting images from T1 VIBE and T2 DESS were compared to that obtained at 7T qualitatively and quantitatively [SWI was only qualitatively compared]. DSI studio was utilized to identify nerves based on analysis of diffusion weighted derived fractional anisotropy images. Images of forearm vasculature were extracted using a paint grow manual segmentation method based on MIPAV [Medical Image Processing, Analysis, and Visualization].High resolution and high quality signal-to-noise ratio [SNR] and contrast-to-noise ratio [CNR]-images of the hand, forearm, and elbow were acquired with nearly homogeneous 7T excitation. Measured [performed on the T1 VIBE and T2 DESS sequences] SNR and CNR values were almost doubled at 7T vs. 3T. Cartilage, synovial fluid and tendon structures could be seen with higher clarity in the 7T T1 and T2 weighted images. SWI allowed high resolution and better quality imaging of large and medium sized arteries and veins, capillary networks and arteriovenous anastomoses at 7T when compared to 3T. 7T diffusion weighted sequence [not performed at 3T] demonstrates that the forearm nerves are clearly delineated by fiber tractography. The

  10. Novel High Spatiotemporal Resolution Versus Standard-of-Care Dynamic Contrast-Enhanced Breast MRI: Comparison of Image Quality.

    Science.gov (United States)

    Morrison, Courtney K; Henze Bancroft, Leah C; DeMartini, Wendy B; Holmes, James H; Wang, Kang; Bosca, Ryan J; Korosec, Frank R; Strigel, Roberta M

    2017-04-01

    Currently, dynamic contrast-enhanced (DCE) breast magnetic resonance imaging (MRI) prioritizes spatial resolution over temporal resolution given the limitations of acquisition techniques. The purpose of our intrapatient study was to assess the ability of a novel high spatial and high temporal resolution DCE breast MRI method to maintain image quality compared with the clinical standard-of-care (SOC) MRI. Thirty patients, each demonstrating a focal area of enhancement (29 benign, 1 cancer) on their SOC MRI, consented to undergo a research DCE breast MRI on a second date. For the research DCE MRI, a method (DIfferential Subsampling with Cartesian Ordering [DISCO]) using pseudorandom k-space sampling, view sharing reconstruction, 2-point Dixon fat-water separation, and parallel imaging was used to produce images with an effective temporal resolution 6 times faster than the SOC MRI (27 vs 168 seconds, respectively). Both the SOC and DISCO MRI scans were acquired with matching spatial resolutions of 0.8 × 0.8 × 1.6 mm. Image quality (distortion/artifacts, resolution, fat suppression, lesion conspicuity, perceived signal-to-noise ratio, and overall image quality) was scored by 3 radiologists in a blinded reader study. Differences in image quality scores between the DISCO and SOC images were all less than 0.8 on a 10-point scale, and both methods were assessed as providing diagnostic image quality in all cases. DISCO images with the same high spatial resolution, but 6 times the effective temporal resolution as the SOC MRI scans, were produced, yielding 20 postcontrast time points with DISCO compared with 3 for the SOC MRI, over the same total time interval. DISCO provided comparable image quality compared with the SOC MRI, while also providing 6 times faster effective temporal resolution and the same high spatial resolution.

  11. Decoding Overlapping Memories in the Medial Temporal Lobes Using High-Resolution fMRI

    Science.gov (United States)

    Chadwick, Martin J.; Hassabis, Demis; Maguire, Eleanor A.

    2011-01-01

    The hippocampus is proposed to process overlapping episodes as discrete memory traces, although direct evidence for this in human episodic memory is scarce. Using green-screen technology we created four highly overlapping movies of everyday events. Participants were scanned using high-resolution fMRI while recalling the movies. Multivariate…

  12. High-resolution MRI predicts steroid injection response in carpal tunnel syndrome patients

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Takatoshi; Oki, Hodaka; Kinoshita, Shunsuke; Yamashita, Yoshiko; Takahashi, Hiroyuki; Hayashida, Yoshiko; Korogi, Yukunori [University of Occupational and Environmental Health School of Medicine, Department of Radiology, Kitakyushu (Japan); Oshige, Takahisa; Sakai, Akinori [University of Occupational and Environmental Health School of Medicine, Department of Orthopaedic Surgery, Kitakyushu (Japan); Matsuyama, Atsushi; Hisaoka, Masanori [University of Occupational and Environmental Health School of Medicine, Department of Pathology and Oncology, Kitakyushu (Japan)

    2014-03-15

    To correlate median nerve T2 signal and shape at the carpal tunnel with steroid injection (SI) response in carpal tunnel syndrome (CTS) patients. One hundred and sixty-three CTS wrists of 92 consecutive patients who were scheduled to undergo SI were prospectively evaluated with 3-T magnetic resonance imaging (MRI) and a nerve conduction study. All patients underwent axial high-resolution T2-weighted MRI (in-plane resolution of 0.25 x 0.25 mm). The CTS wrists were classified into three groups according to the nerve T2 signal and the flattening ratio at the hook of hamate level: group 1, high and oval; group 2, high and flat; group 3, low and flat. Clinical response to SI was evaluated at 6 months after injection. One hundred and thirteen of the 163 wrists (69.3 %) responded well to SI. The percentage of improvement was 81.7 % (49/60) in group 1, 69.9 % (51/73) in group 2, and 43.3 % (13/30) in group 3 (P < 0.01). On stepwise logistic regression analysis high-resolution MRI was the only significant independent factor for SI response in CTS patients (P < 0.01). High-resolution MRI correlates well with SI response in CTS patients and seems useful for predicting SI response. (orig.)

  13. Dual-TRACER: High resolution fMRI with constrained evolution reconstruction.

    Science.gov (United States)

    Li, Xuesong; Ma, Xiaodong; Li, Lyu; Zhang, Zhe; Zhang, Xue; Tong, Yan; Wang, Lihong; Sen Song; Guo, Hua

    2017-03-02

    fMRI with high spatial resolution is beneficial for studies in psychology and neuroscience, but is limited by various factors such as prolonged imaging time, low signal to noise ratio and scarcity of advanced facilities. Compressed Sensing (CS) based methods for accelerating fMRI data acquisition are promising. Other advanced algorithms like k-t FOCUSS or PICCS have been developed to improve performance. This study aims to investigate a new method, Dual-TRACER, based on Temporal Resolution Acceleration with Constrained Evolution Reconstruction (TRACER), for accelerating fMRI acquisitions using golden angle variable density spiral. Both numerical simulations and in vivo experiments at 3T were conducted to evaluate and characterize this method. Results show that Dual-TRACER can provide functional images with a high spatial resolution (1×1mm(2)) under an acceleration factor of 20 while maintaining hemodynamic signals well. Compared with other investigated methods, dual-TRACER provides a better signal recovery, higher fMRI sensitivity and more reliable activation detection. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Improved Hardware for Higher Spatial Resolution Strain-ENCoded (SENC) Breast MRI for Strain Measurements

    Science.gov (United States)

    Harouni, Ahmed A.; Hossain, Jakir; Jacobs, Michael A.; Osman, Nael F.

    2012-01-01

    Introduction Early detection of breast lesions using mammography has resulted in lower mortality-rates. However, some breast lesions are mammography occult and magnetic resonance imaging (MRI) is recommended, but has lower specificity. It is possible to achieve higher specificity by using Strain-ENCoded (SENC) MRI and/or magnetic resonance elastography(MRE). SENC breast MRI can measure the strain properties of breast tissue. Similarly, MRE is used to measure elasticity (i.e., shear stiffness) of different tissue compositions interrogating the tissue mechanical properties. Reports have shown that malignant tumors are 3–13 times stiffer than normal tissue and benign tumors. Methods We have developed a Strain-ENCoded (SENC) breast hardware device capable of periodically compressing the breast, thus allowing for longer scanning time and measuring the strain characteristics of breast tissue. This hardware enabled us to use SENC MRI with high spatial resolution (1×1×5mm3) instead of Fast SENC(FSENC). Simple controls and multiple safety measures were added to ensure accurate, repeatable and safe in-vivo experiments. Results Phantom experiments showed that SENC breast MRI has higher SNR and CNR than FSENC under different scanning resolutions. Finally, the SENC breast device reproducibility measurements resulted in a difference of less than one mm with a 1% strain difference. Conclusion SENC breast MR images have higher SNR and CNR than FSENC images. Thus, combining SENC breast strain measurements with diagnostic breast MRI to differentiate benign from malignant lesions could potentially increase the specificity of diagnosis in the clinical setting. PMID:21440464

  15. Improved hardware for higher spatial resolution strain-encoded (SENC) breast MRI for strain measurements.

    Science.gov (United States)

    Harouni, Ahmed A; Hossain, Jakir; Jacobs, Michael A; Osman, Nael F

    2011-06-01

    Early detection of breast lesions using mammography has resulted in lower mortality rates. However, some breast lesions are mammography occult, and magnetic resonance imaging (MRI) is recommended, but it has lower specificity. It is possible to achieve higher specificity by using strain-encoded (SENC) MRI and/or magnetic resonance elastography. SENC breast MRI can measure the strain properties of breast tissue. Similarly, magnetic resonance elastography is used to measure the elasticity (ie, shear stiffness) of different tissue compositions interrogating the tissue mechanical properties. Reports have shown that malignant tumors are three to 13 times stiffer than normal tissue and benign tumors. The investigators have developed a SENC breast hardware device capable of periodically compressing the breast, thus allowing for longer scanning time and measuring the strain characteristics of breast tissue. This hardware enables the use of SENC MRI with high spatial resolution (1 × 1 × 5 mm(3)) instead of fast SENC imaging. Simple controls and multiple safety measures were added to ensure accurate, repeatable, and safe in vivo experiments. Phantom experiments showed that SENC breast MRI has higher signal-to-noise ratio and contrast-to-noise ratio than fast SENC imaging under different scanning resolutions. Finally, the SENC breast device reproducibility measurements resulted in a difference of breast magnetic resonance images have higher signal-to-noise ratio and contrast-to-noise ratios than fast SENC images. Thus, combining SENC breast strain measurements with diagnostic breast MRI to differentiate benign from malignant lesions could potentially increase the specificity of diagnosis in the clinical setting. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

  16. High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Pei-Hsin; Chung, Hsiao-Wen [Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Tsai, Ping-Huei [Imaging Research Center, Taipei Medical University, Taipei 11031, Taiwan and Department of Medical Imaging, Taipei Medical University Hospital, Taipei Medical University, Taipei 11031, Taiwan (China); Wu, Ming-Long, E-mail: minglong.wu@csie.ncku.edu.tw [Institute of Medical Informatics, National Cheng-Kung University, Tainan 70101, Taiwan and Department of Computer Science and Information Engineering, National Cheng-Kung University, Tainan 70101, Taiwan (China); Chuang, Tzu-Chao [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Shih, Yi-Yu [Siemens Limited Healthcare Sector, Taipei 11503, Taiwan (China); Huang, Teng-Yi [Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

    2013-12-15

    Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm{sup 3} achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm{sup 3} voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm{sup 3} to 0.43 × 0.43 × 2 mm{sup 3} has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain.

  17. In vivo high-resolution 7 Tesla MRI shows early and diffuse cortical alterations in CADASIL.

    Science.gov (United States)

    De Guio, François; Reyes, Sonia; Vignaud, Alexandre; Duering, Marco; Ropele, Stefan; Duchesnay, Edouard; Chabriat, Hugues; Jouvent, Eric

    2014-01-01

    Recent data suggest that early symptoms may be related to cortex alterations in CADASIL (Cerebral Autosomal-Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy), a monogenic model of cerebral small vessel disease (SVD). The aim of this study was to investigate cortical alterations using both high-resolution T2* acquisitions obtained with 7 Tesla MRI and structural T1 images with 3 Tesla MRI in CADASIL patients with no or only mild symptomatology (modified Rankin's scale ≤1 and Mini Mental State Examination (MMSE) ≥24). Complete reconstructions of the cortex using 7 Tesla T2* acquisitions with 0.7 mm isotropic resolution were obtained in 11 patients (52.1±13.2 years, 36% male) and 24 controls (54.8±11.0 years, 42% male). Seven Tesla T2* within the cortex and cortical thickness and morphology obtained from 3 Tesla images were compared between CADASIL and control subjects using general linear models. MMSE, brain volume, cortical thickness and global sulcal morphology did not differ between groups. By contrast, T2* measured by 7 Tesla MRI was significantly increased in frontal, parietal, occipital and cingulate cortices in patients after correction for multiple testing. These changes were not related to white matter lesions, lacunes or microhemorrhages in patients having no brain atrophy compared to controls. Seven Tesla MRI, by contrast to state of the art post-processing of 3 Tesla acquisitions, shows diffuse T2* alterations within the cortical mantle in CADASIL whose origin remains to be determined.

  18. High-resolution MRI using orbit surface coils for the evaluation of metastatic risk factors in 143 children with retinoblastoma. Part 1: MRI vs. histopathology

    Energy Technology Data Exchange (ETDEWEB)

    Sirin, Selma; Schlamann, Marc; Schweiger, Bernd; Goericke, Sophia L. [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Metz, Klaus A. [University Hospital Essen, Department of Pathology and Neuropathology, Essen (Germany); Bornfeld, Norbert; Holdt, Markus [University Hospital Essen, Department of Ophthalmology, Essen (Germany); Temming, Petra; Schuendeln, Michael M. [University Hospital Essen, Department of Pediatric Hematology and Oncology, Essen (Germany)

    2015-08-15

    A reliable detection of metastatic risk factors is important for children with retinoblastoma to choose the right therapeutic regimen. First studies using high-resolution magnetic resonance imaging (MRI) with orbit surface coils were promising. The aim of this study was therefore to evaluate the ability of high-resolution MRI to detect metastatic and especially advanced metastatic risk factors in a large group of children with retinoblastoma. One hundred forty-three consecutive children with retinoblastoma (148 enucleated eyes, 64 girls, 79 boys, mean age 19.7 ± 15.3) who received pretherapeutical high-resolution MRI with orbit surface coils on 1.5 T MR scanner systems between 2007 and 2012 and subsequent primary enucleation within 14 days were included in this retrospective study. Image analysis was performed by two neuroradiologists experienced in ocular imaging in consensus. Histopathology served as gold standard. Sensitivity/specificity for the detection of metastatic risk factors using high-resolution MRI with orbit surface coils were 60 %/88.7 % for postlaminar optic nerve infiltration, 65.5 %/95.6 % for choroidal invasion, 100 %/99.3 % for scleral invasion, and 100 %/100 % for peribulbar fat invasion, respectively. The results increased for the detection of advanced metastatic risk factors, 81.8 %/89.1 % for deep postlaminar optic nerve infiltration, 70.6 %/97.6 % for massive choroidal invasion. High-resolution MRI is clinically valuable for the detection of metastatic, especially of advanced metastatic risk factors in children with retinoblastoma. (orig.)

  19. Sparse Bayesian Inference of White Matter Fiber Orientations from Compressed Multi-resolution Diffusion MRI.

    Science.gov (United States)

    Pisharady, Pramod Kumar; Duarte-Carvajalino, Julio M; Sotiropoulos, Stamatios N; Sapiro, Guillermo; Lenglet, Christophe

    2015-10-01

    The RubiX [1] algorithm combines high SNR characteristics of low resolution data with high spacial specificity of high resolution data, to extract microstructural tissue parameters from diffusion MRI. In this paper we focus on estimating crossing fiber orientations and introduce sparsity to the RubiX algorithm, making it suitable for reconstruction from compressed (under-sampled) data. We propose a sparse Bayesian algorithm for estimation of fiber orientations and volume fractions from compressed diffusion MRI. The data at high resolution is modeled using a parametric spherical deconvolution approach and represented using a dictionary created with the exponential decay components along different possible directions. Volume fractions of fibers along these orientations define the dictionary weights. The data at low resolution is modeled using a spatial partial volume representation. The proposed dictionary representation and sparsity priors consider the dependence between fiber orientations and the spatial redundancy in data representation. Our method exploits the sparsity of fiber orientations, therefore facilitating inference from under-sampled data. Experimental results show improved accuracy and decreased uncertainty in fiber orientation estimates. For under-sampled data, the proposed method is also shown to produce more robust estimates of fiber orientations.

  20. High-resolution MRI predicts steroid injection response in carpal tunnel syndrome patients.

    Science.gov (United States)

    Aoki, Takatoshi; Oshige, Takahisa; Matsuyama, Atsushi; Oki, Hodaka; Kinoshita, Shunsuke; Yamashita, Yoshiko; Takahashi, Hiroyuki; Hayashida, Yoshiko; Sakai, Akinori; Hisaoka, Masanori; Korogi, Yukunori

    2014-03-01

    To correlate median nerve T2 signal and shape at the carpal tunnel with steroid injection (SI) response in carpal tunnel syndrome (CTS) patients. One hundred and sixty-three CTS wrists of 92 consecutive patients who were scheduled to undergo SI were prospectively evaluated with 3-T magnetic resonance imaging (MRI) and a nerve conduction study. All patients underwent axial high-resolution T2-weighted MRI (in-plane resolution of 0.25 × 0.25 mm). The CTS wrists were classified into three groups according to the nerve T2 signal and the flattening ratio at the hook of hamate level: group 1, high and oval; group 2, high and flat; group 3, low and flat. Clinical response to SI was evaluated at 6 months after injection. One hundred and thirteen of the 163 wrists (69.3%) responded well to SI. The percentage of improvement was 81.7% (49/60) in group 1, 69.9% (51/73) in group 2, and 43.3% (13/30) in group 3 (P carpal tunnel syndrome. • MRI helps in therapeutic decision-making whenever steroid injection is considered. • T2 signal decrease of the median nerve correlates with poor outcome. • T2 signal decrease of median nerve may reflect fibrosis and amyloid deposition.

  1. A computational atlas of the hippocampal formation using ex vivo, ultra-high resolution MRI: Application to adaptive segmentation of in vivo MRI

    DEFF Research Database (Denmark)

    Iglesias, Juan Eugenio; Augustinack, Jean C.; Nguyen, Khoa

    2015-01-01

    an algorithm that can analyze multimodal data and adapt to variations in MRI contrast due to differences in acquisition hardware or pulse sequences. The applicability of the atlas, which we are releasing as part of FreeSurfer (version 6.0), is demonstrated with experiments on three different publicly available......Automated analysis of MRI data of the subregions of the hippocampus requires computational atlases built at a higher resolution than those that are typically used in current neuroimaging studies. Here we describe the construction of a statistical atlas of the hippocampal formation at the subregion...... level using ultra-high resolution, ex vivo MRI. Fifteen autopsy samples were scanned at 0.13 mm isotropic resolution (on average) using customized hardware. The images were manually segmented into 13 different hippocampal substructures using a protocol specifically designed for this study; precise...

  2. Imaging of posterior tibial tendon dysfunction—Comparison of high-resolution ultrasound and 3 T MRI

    Energy Technology Data Exchange (ETDEWEB)

    Arnoldner, Michael A., E-mail: michael.arnoldner@meduniwien.ac.at [Medical University of Vienna, Vienna General Hospital, Department of Biomedical Imaging and Image-guided Therapy, Währinger Gürtel 18-20, 1090 Vienna (Austria); Gruber, Michael [Medical University of Vienna, Vienna General Hospital, Department of Biomedical Imaging and Image-guided Therapy, Währinger Gürtel 18-20, 1090 Vienna (Austria); Syré, Stefanie [Medical University of Vienna, Vienna General Hospital, Department of Trauma-Surgery, Währinger Gürtel 18-20, 1090 Vienna (Austria); Kristen, Karl-Heinz [Foot & Ankle Centre Vienna, Alser Straße 43/8, 1080 Vienna (Austria); Trnka, Hans-Jörg [Foot & Ankle Centre Vienna, Alser Straße 43/8, 1080 Vienna (Austria); Orthopaedic Hospital Vienna, Speisinger Straße 109, 1130 Vienna (Austria); Kainberger, Franz; Bodner, Gerd [Medical University of Vienna, Vienna General Hospital, Department of Biomedical Imaging and Image-guided Therapy, Währinger Gürtel 18-20, 1090 Vienna (Austria)

    2015-09-15

    Highlights: • 18 MHz high-resolution ultrasound appears to be slightly more accurate than 3 T MRI in the diagnosis of PTTD. • High-resolution ultrasound is recommended as an initial diagnostic tool. • Long-lasting PTT discomfort may require MRI. • Other pathologies can mimic PTTD. - Abstract: Purpose: Posterior tibial tendon dysfunction is the most common cause of acquired asymmetric flatfoot deformity. The purpose of this study was to determine and compare the diagnostic value of MRI and high-resolution ultrasound (HR-US) in posterior tibial tendon dysfunction (PTTD), and assess their correlation with intraoperative findings. Materials and methods: We reviewed 23 posterior tibial tendons in 23 patients with clinical findings of PTTD (13 females, 10 males; mean age, 50 years) with 18 MHz HR-US and 3 T MRI. Surgical intervention was performed in nine patients. Results: HR-US findings included 2 complete tears, 6 partial tears, 10 tendons with tendinosis, and 5 unremarkable tendons. MRI demonstrated 2 complete tears, 7 partial tears, 10 tendons with tendinosis, and 4 unremarkable tendons. HR-US and MRI were concordant in 20/23 cases (87%). Image findings for HR-US were confirmed in six of nine patients (66.7%) by intraoperative inspection, whereas imaging findings for MRI were concordant with five of nine cases (55.6%). Conclusion: Our results indicate that HR-US can be considered slightly more accurate than MRI in the detection of PTTD.

  3. A High-resolution Atlas and Statistical Model of the Vocal Tract from Structural MRI.

    Science.gov (United States)

    Woo, Jonghye; Lee, Junghoon; Murano, Emi Z; Xing, Fangxu; Al-Talib, Meena; Stone, Maureen; Prince, Jerry L

    Magnetic resonance imaging (MRI) is an essential tool in the study of muscle anatomy and functional activity in the tongue. Objective assessment of similarities and differences in tongue structure and function has been performed using unnormalized data, but this is biased by the differences in size, shape, and orientation of the structures. To remedy this, we propose a methodology to build a 3D vocal tract atlas based on structural MRI volumes from twenty normal subjects. We first constructed high-resolution volumes from three orthogonal stacks. We then removed extraneous data so that all 3D volumes contained the same anatomy. We used an unbiased diffeomorphic groupwise registration using a cross-correlation similarity metric. Principal component analysis was applied to the deformation fields to create a statistical model from the atlas. Various evaluations and applications were carried out to show the behaviour and utility of the atlas.

  4. Moderate value of non-contrast magnetic resonance imaging after non-dislocating shoulder trauma.

    Science.gov (United States)

    Banerjee, Marc; Müller-Hübenthal, Jonas; Grimme, Stefan; Balke, Maurice; Bouillon, Bertil; Lefering, Rolf; Goßmann, Axel; Shafizadeh, Sven

    2016-06-01

    The purpose of the present study was to determine the value of shoulder magnetic resonance imaging (MRI) obtained in the community setting interpreted by musculoskeletal radiologists in patients with shoulder pain initiated by a single non-dislocating shoulder trauma. In 56 of 61 consecutive patients who underwent shoulder arthroscopy due to pain after a single non-dislocating shoulder trauma, the data sets of non-contrast MRI were complete. These were retrospectively interpreted by three radiologists specialized on musculoskeletal MRI who were blinded for patients' history and who did not have access to the reports of arthroscopy. Standard evaluation forms were used to assess the MRIs for superior labrum anterior and posterior (SLAP) lesions, anterior or posterior labrum lesions, lesions of the long head of biceps tendon (LHB) and for partial tears of the supraspinatus tendon and the upper quarter of the subscapularis tendon. Quality of the MRI was assessed by each radiologist on a four-point scale. The pooled sensitivity for the three radiologists for the detection of SLAP lesions was 45.0 %, for anterior or posterior labrum tears 77.8 and 66.7 %, for lesions of the LHB 63.2 % and for partial tears of the supraspinatus or subscapularis tendon tears 84.8 and 33.3 %. Corresponding inter-rater reliabilities were poor (SLAP lesions) to substantial (anterior labrum tears). Quality of MRI only influenced the accuracy for the detection of posterior labrum tears. A non-contrast shoulder MRI obtained in the community setting after non-dislocating shoulder trauma has a moderate sensitivity for most intraarticular pathologies when interpreted by musculoskeletal radiologists. Accuracy is dependent on the observer and not on the assessed quality. Case series, Level IV.

  5. Human brain diffusion tensor imaging at submillimeter isotropic resolution on a 3Tesla clinical MRI scanner.

    Science.gov (United States)

    Chang, Hing-Chiu; Sundman, Mark; Petit, Laurent; Guhaniyogi, Shayan; Chu, Mei-Lan; Petty, Christopher; Song, Allen W; Chen, Nan-kuei

    2015-09-01

    The advantages of high-resolution diffusion tensor imaging (DTI) have been demonstrated in a recent post-mortem human brain study (Miller et al., NeuroImage 2011;57(1):167-181), showing that white matter fiber tracts can be much more accurately detected in data at a submillimeter isotropic resolution. To our knowledge, in vivo human brain DTI at a submillimeter isotropic resolution has not been routinely achieved yet because of the difficulty in simultaneously achieving high resolution and high signal-to-noise ratio (SNR) in DTI scans. Here we report a 3D multi-slab interleaved EPI acquisition integrated with multiplexed sensitivity encoded (MUSE) reconstruction, to achieve high-quality, high-SNR and submillimeter isotropic resolution (0.85×0.85×0.85mm(3)) in vivo human brain DTI on a 3Tesla clinical MRI scanner. In agreement with the previously reported post-mortem human brain DTI study, our in vivo data show that the structural connectivity networks of human brains can be mapped more accurately and completely with high-resolution DTI as compared with conventional DTI (e.g., 2×2×2mm(3)). Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Prioritizing spatial accuracy in high-resolution fMRI data using multivariate feature weight mapping

    Directory of Open Access Journals (Sweden)

    Johannes eStelzer

    2014-04-01

    Full Text Available Although ultra-high-field fMRI at field strengths of 7T or above provides substantial gains in BOLD contrast-to-noise ratio, when very high-resolution fMRI is required such gains are inevitably reduced. The improvement in sensitivity provided by multivariate analysis techniques, as compared with univariate methods, then becomes especially welcome. Information mapping approaches are commonly used, such as the searchlight technique, which take into account the spatially distributed patterns of activation in order to predict stimulus conditions. However, the popular searchlight decoding technique, in particular, has been found to be prone to spatial inaccuracies. For instance, the spatial extent of informative areas is generally exaggerated, and their spatial configuration is distorted. We propose the combination of a nonparametric and permutation-based statistical framework with linear classifiers. We term this new combined method Feature Weight Mapping (FWM. The main goal of the proposed method is to map the specific contribution of each voxel to the classification decision while including a correction for the multiple comparisons problem. Next, we compare this new method to the searchlight approach using a simulation and ultra-high-field 7T experimental data. We found that the searchlight method led to spatial inaccuracies that are especially noticeable in high-resolution fMRI data. In contrast, FWM was more spatially precise, revealing both informative anatomical structures as well as the direction by which voxels contribute to the classification. By maximizing the spatial accuracy of ultra-high-field fMRI results, global multivariate methods provide a substantial improvement for characterizing structure-function relationships.

  7. High resolution imaging of the mitral valve in the natural state with 7 Tesla MRI.

    Science.gov (United States)

    Stephens, Sam E; Liachenko, Serguei; Ingels, Neil B; Wenk, Jonathan F; Jensen, Morten O

    2017-01-01

    Imaging techniques of the mitral valve have improved tremendously during the last decade, but challenges persist. The delicate changes in annulus shape and papillary muscle position throughout the cardiac cycle have significant impact on the stress distribution in the leaflets and chords, thus preservation of anatomically accurate positioning is critical. The aim of this study was to develop an in vitro method and apparatus for obtaining high-resolution 3D MRI images of porcine mitral valves in both the diastolic and systolic configurations with physiologically appropriate annular shape, papillary muscle positions and orientations, specific to the heart from which the valve was harvested. Positioning and mounting was achieved through novel, customized mounting hardware consisting of papillary muscle and annulus holders with geometries determined via pre-mortem ultrasonic intra-valve measurements. A semi-automatic process was developed and employed to tailor Computer Aided Design models of the holders used to mount the valve. All valve mounting hardware was 3D printed using a stereolithographic printer, and the material of all fasteners used were brass for MRI compatibility. The mounted valves were placed within a clear acrylic case, capable of holding a zero-pressure and pressurized liquid bath of a MRI-compatible fluid. Obtaining images from the valve submerged in liquid fluid mimics the natural environment surrounding the valve, avoiding artefacts due to tissue surface tension mismatch and gravitational impact on tissue shape when not neutrally buoyant. Fluid pressure was supplied by reservoirs held at differing elevations and monitored and controlled to within ±1mmHg to ensure that the valves remained steady. The valves were scanned in a 7 Tesla MRI system providing a voxel resolution of at least 80μm. The systematic approach produced 3D datasets of high quality which, when combined with physiologically accurate positioning by the apparatus, can serve as an

  8. Feasibility of high-resolution pituitary MRI at 7.0 tesla

    Energy Technology Data Exchange (ETDEWEB)

    Rotte, Alexandra A.J. de; Kolk, Anja G. van der; Rutgers, Dik; Luijten, Peter R.; Hendrikse, Jeroen [University Medical Center Utrecht, Department of Radiology, Heidelberglaan 100, Postbox 85500, Utrecht (Netherlands); Zelissen, Pierre M.J. [University Medical Center Utrecht, Department of Internal Medicine (Section of Endocrinology), Utrecht (Netherlands); Visser, Fredy [University Medical Center Utrecht, Department of Radiology, Heidelberglaan 100, Postbox 85500, Utrecht (Netherlands); Philips Healthcare, Best (Netherlands)

    2014-08-15

    Since the pituitary gland measures 3-8 mm, imaging with the highest possible spatial resolution is important for the detection of even smaller lesions such as those seen in Cushing's disease. In the current feasibility study, we tested a multi-sequence MRI protocol to visualize the pituitary gland in high resolution at 7.0 Tesla (7.0 T). Ten healthy volunteers were examined with a 7.0 T pituitary gland protocol. The protocol consisted of a T1-weighted magnetization-prepared inversion recovery (MPIR) turbo spin-echo (TSE) sequence and a T2-weighted TSE sequence. Additionally, this protocol was tested in five patients with clinical and biochemical suspicion of a microadenoma. The dedicated protocol was successful in visualizing normal pituitary anatomy. At 7.0 T compared to 1.5 T, four times as many slices covered the pituitary gland in sagittal and coronal direction. In three patients, a lesion was diagnosed at 7.0 T, and was confirmed by histopathology to be a microadenoma. Head-to-head comparisons of 7.0 T with 1.5 T and 3.0 T are needed with larger samples of patients and with imaging times feasible for clinical settings. However, the current study suggests that high-resolution 7.0 T MRI of the pituitary gland may provide new perspectives when used as a second-line diagnostic examination in the specific context of Cushing's disease. (orig.)

  9. Noncontrast peripheral MRA with spiral echo train imaging.

    Science.gov (United States)

    Fielden, Samuel W; Mugler, John P; Hagspiel, Klaus D; Norton, Patrick T; Kramer, Christopher M; Meyer, Craig H

    2015-03-01

    To develop a spin echo train sequence with spiral readout gradients with improved artery-vein contrast for noncontrast angiography. Venous T2 becomes shorter as the echo spacing is increased in echo train sequences, improving contrast. Spiral acquisitions, due to their data collection efficiency, facilitate long echo spacings without increasing scan times. Bloch equation simulations were performed to determine optimal sequence parameters, and the sequence was applied in five volunteers. In two volunteers, the sequence was performed with a range of echo times and echo spacings to compare with the theoretical contrast behavior. A Cartesian version of the sequence was used to compare contrast appearance with the spiral sequence. Additionally, spiral parallel imaging was optionally used to improve image resolution. In vivo, artery-vein contrast properties followed the general shape predicted by simulations, and good results were obtained in all stations. Compared with a Cartesian implementation, the spiral sequence had superior artery-vein contrast, better spatial resolution (1.2 mm(2) versus 1.5 mm(2) ), and was acquired in less time (1.4 min versus 7.5 min). The spiral spin echo train sequence can be used for flow-independent angiography to generate three-dimensional angiograms of the periphery quickly and without the use of contrast agents. © 2014 Wiley Periodicals, Inc.

  10. MRI

    DEFF Research Database (Denmark)

    Schroeter, Aileen; Rudin, Markus; Gianolio, Eliana

    2017-01-01

    This chapter discusses principles of nuclear magnetic resonance (NMR) and MRI followed by a survey on the major classes of MRI contrast agents (CA), their modes of action, and some of the most significative applications. The two more established classes of MRI-CA are represented by paramagnetic...

  11. Non Local Spatial and Angular Matching: Enabling higher spatial resolution diffusion MRI datasets through adaptive denoising.

    Science.gov (United States)

    St-Jean, Samuel; Coupé, Pierrick; Descoteaux, Maxime

    2016-08-01

    Diffusion magnetic resonance imaging (MRI) datasets suffer from low Signal-to-Noise Ratio (SNR), especially at high b-values. Acquiring data at high b-values contains relevant information and is now of great interest for microstructural and connectomics studies. High noise levels bias the measurements due to the non-Gaussian nature of the noise, which in turn can lead to a false and biased estimation of the diffusion parameters. Additionally, the usage of in-plane acceleration techniques during the acquisition leads to a spatially varying noise distribution, which depends on the parallel acceleration method implemented on the scanner. This paper proposes a novel diffusion MRI denoising technique that can be used on all existing data, without adding to the scanning time. We first apply a statistical framework to convert both stationary and non stationary Rician and non central Chi distributed noise to Gaussian distributed noise, effectively removing the bias. We then introduce a spatially and angular adaptive denoising technique, the Non Local Spatial and Angular Matching (NLSAM) algorithm. Each volume is first decomposed in small 4D overlapping patches, thus capturing the spatial and angular structure of the diffusion data, and a dictionary of atoms is learned on those patches. A local sparse decomposition is then found by bounding the reconstruction error with the local noise variance. We compare against three other state-of-the-art denoising methods and show quantitative local and connectivity results on a synthetic phantom and on an in-vivo high resolution dataset. Overall, our method restores perceptual information, removes the noise bias in common diffusion metrics, restores the extracted peaks coherence and improves reproducibility of tractography on the synthetic dataset. On the 1.2 mm high resolution in-vivo dataset, our denoising improves the visual quality of the data and reduces the number of spurious tracts when compared to the noisy acquisition. Our

  12. Radiofrequency configuration to facilitate bilateral breast 31P MR spectroscopic imaging and high-resolution MRI at 7 Tesla

    NARCIS (Netherlands)

    van der Velden, Tijl A.; Italiaander, Michel; van der Kemp, Wybe J M; Raaijmakers, AJE; Schmitz, A. M Th; Luijten, Peter R.; Boer, VO; Klomp, DWJ

    2015-01-01

    PURPOSE: High-resolution MRI combined with phospholipid detection may improve breast cancer grading. Currently, configurations are optimized for either high-resolution imaging or 31 P spectroscopy. To be able to perform both imaging as well as spectroscopy in a single session, we integrated a 1 H

  13. Predictive Modelling of Cardiac 2D Multi-Slice MRI with Simultaneous Resolution of Cardiac and Respiratory Motion

    DEFF Research Database (Denmark)

    Pedersen, Henrik; Ólafsdóttir, Hildur; Darkner, Sune

    2009-01-01

    This paper introduces a novel approach to modelling of volumetric cardiac magnetic resonance imaging (MRI) with simultaneous resolution of cardiac and respiratory motion. The major challenge is that the inherent slow nature of MRI prevents obtaining real-time volumetric images of the heart...... with sufficient spatial and temporal resolution. To overcome this problem our method predicts pixel intensities in multiple 2D slices, acquired with high spatial and temporal resolution, and subsequently assembles these into volumetric data sets. The prediction is based on external motion sensors, in our case...

  14. Influence of field strength, coil type and image resolution on assessment of synovitis by unenhanced MRI--a comparison with contrast-enhanced MRI

    DEFF Research Database (Denmark)

    Eshed, Iris; Krabbe, Simon; Østergaard, Mikkel

    2015-01-01

    joints) at 4 different field-strengths (0.23 T/0.6 T/1.5 T/3.0 T) on the same day. Seven protocols using a STIR sequence with different field-strengths, coils (flex coils/dedicated phased-array extremity coils) and resolution were applied and scored blindly for synovitis (OMERACT-RAMRIS method). A 1.5 T......OBJECTIVES: To explore if the reliability of synovitis assessment by unenhanced MRI is influenced by different MRI field-strengths, coil types and image resolutions in RA patients. METHODS: Forty-one RA patients and 12 healthy controls underwent hand MRI (wrist and 2(nd)--5(th) metacarpophalangeal...

  15. Is your system calibrated? MRI gradient system calibration for pre-clinical, high-resolution imaging.

    Directory of Open Access Journals (Sweden)

    James O'Callaghan

    Full Text Available High-field, pre-clinical MRI systems are widely used to characterise tissue structure and volume in small animals, using high resolution imaging. Both applications rely heavily on the consistent, accurate calibration of imaging gradients, yet such calibrations are typically only performed during maintenance sessions by equipment manufacturers, and potentially with acceptance limits that are inadequate for phenotyping. To overcome this difficulty, we present a protocol for gradient calibration quality assurance testing, based on a 3D-printed, open source, structural phantom that can be customised to the dimensions of individual scanners and RF coils. In trials on a 9.4 T system, the gradient scaling errors were reduced by an order of magnitude, and displacements of greater than 100 µm, caused by gradient non-linearity, were corrected using a post-processing technique. The step-by-step protocol can be integrated into routine pre-clinical MRI quality assurance to measure and correct for these errors. We suggest that this type of quality assurance is essential for robust pre-clinical MRI experiments that rely on accurate imaging gradients, including small animal phenotyping and diffusion MR.

  16. Volume measurement by using super-resolution MRI: application to prostate volumetry

    CERN Document Server

    Oubel, Estanislao; Iannessi, Antoine

    2015-01-01

    Accuracy and precision of measurements are important for patient follow up in oncology but, unfortunately, partial volume effects introduce an undesired variability between observers. Super resolution techniques (SR) combine multiple acquisitions of an object into a single image richer in details. Herein, the use of SR for reducing variability is investigated in the specific context of prostate measurements. Prostate is typically imaged by T2-weighted MRI in three perpendicular low resolution images, each of them presenting partial volume effects in the direction of the slice selection gradient. SR techniques allow to combine these images into an image presenting the same level of details in all directions. This is expected to increase the accuracy and reproducibility of volume measurements, which in turn improves other derived measurements like PSA density.

  17. An optical setup for electric field measurements in MRI with high spatial resolution

    Science.gov (United States)

    Reiss, Simon; Bitzer, Andreas; Bock, Michael

    2015-06-01

    Electric field measurements in the magnetic resonance (MR) imaging environment are important to assess potentially dangerous radio-frequency (RF) heating in the vicinity of metallic structures such as coils, implants or catheters. So far, E-field measurements have been performed with dipole antennas that lag of limited spatial resolution and which are difficult to use in the magnet bore as they interfere with the RF transmit field of the MRI system. In this work an electro-optic sensor is presented that utilizes the Pockels effect to measure the E-field in a clinical MR system with high spatial resolution. This sensor consists of dielectric materials only and thus, it only minimally influences the measured E-field distribution. A 10 m long flexible optical fiber connects the small sensor head to a remote processing unit where the optical signal is transformed into an electrical output signal. Spatially resolved qualitative E-field measurements were performed in a 1.5 T clinical MR system in the vicinity of metallic samples and an active tracking catheter with a resolution of up to 1 mm. The near-field pattern of a resonant U-shaped metallic sample was clearly identified and compared with numerical simulations. A more complex field behavior was found for the tracking catheter where strong E-field enhancements were observed at the distal tip and at its proximal part outside the phantom solution. Due to its sub-mm spatial resolution the optical sensor approach provides detailed insight into the complex and difficult to access field distributions close to implants and metallic structures and has turned out to be promising tool for MRI field and safety inspections.

  18. High-resolution phase-contrast MRI of aortic and pulmonary blood flow during rest and physical exercise using a MRI compatible bicycle ergometer

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Tim Frederik, E-mail: tim.weber@med.uni-heidelberg.de [Department of Diagnostic and Interventional Radiology, University Medical Center Heidelberg, INF 110, 69120 Heidelberg (Germany); Department of Radiology, German Cancer Research Center, INF 280, 69120 Heidelberg (Germany); Tengg-Kobligk, Hendrik von, E-mail: hendrik.tengg-kobligk@med.uni-heidelberg.de [Department of Diagnostic and Interventional Radiology, University Medical Center Heidelberg, INF 110, 69120 Heidelberg (Germany); Department of Radiology, German Cancer Research Center, INF 280, 69120 Heidelberg (Germany); Kopp-Schneider, Annette, E-mail: kopp@dkfz-heidelberg.de [Department of Biostatistics, German Cancer Research Center, INF 280, 69120 Heidelberg (Germany); Ley-Zaporozhan, Julia, E-mail: julia.ley-zaporozhan@med.uni-heidelberg.de [Department of Pediatric Radiology, University Medical Center Heidelberg, INF 430, 69120 Heidelberg (Germany); Kauczor, Hans-Ulrich, E-mail: hans-ulrich.kauczor@med.uni-heidelberg.de [Department of Diagnostic and Interventional Radiology, University Medical Center Heidelberg, INF 110, 69120 Heidelberg (Germany); Ley, Sebastian, E-mail: sebastian.ley@med.uni.heidelberg.de [Department of Radiology, German Cancer Research Center, INF 280, 69120 Heidelberg (Germany); Department of Pediatric Radiology, University Medical Center Heidelberg, INF 430, 69120 Heidelberg (Germany)

    2011-10-15

    Purpose: To establish high-resolution phase-contrast magnetic resonance imaging (PC-MRI) using a MRI compatible bicycle ergometer to quantify aortic and pulmonary blood flow during resting conditions and exercise. Materials and methods: In 20 healthy volunteers (mean age, 26.8 {+-} 5.0 years) high-resolution PC-MRI (mean temporal resolution, 7.4 {+-} 3.2 ms) was performed in the ascending aorta (AA) and main pulmonary artery (PA) during physical rest and three exercise stages: stage 1, no-load operation; stage 2, heart rate increase 40% compared to rest; stage 3, heart rate increase 80% compared to rest. Flow quantification in AA and PA included flow volume (FV), average velocity (AV), peak velocity (PV) and time to PV (TP). Results: In stage 1 only TP demonstrated a significant change. With progression to stage 2, all parameters altered significantly. Flow measurements during stage 3 evidenced further alterations only of AV and TP regarding both AA and PA. The deviation of the heart rate from the desired target value was significantly higher for stage 3 compared to stage 2, and 15% of the subjects did not reach the desired target heart rate of stage 3 at all. Conclusion: Flow quantification by high-resolution PC-MRI during exercise using a MRI compatible bicycle ergometer is feasible. Medium exercise stages are necessary and sufficient to demonstrate flow alterations in healthy volunteers. PC-MRI ergometry may give insights into aberrant hemodynamic conditions in patients with cardiovascular and pulmonary disease.

  19. Noncontrast-Enhanced Magnetic Resonance Versus Computed Tomography Angiography in Preoperative Evaluation of Potential Living Renal Donors

    DEFF Research Database (Denmark)

    Blankholm, Anne Dorte; Pedersen, Bodil G; Østrat, Ernst Ø

    2015-01-01

    RATIONALE AND OBJECTIVES: Living renal donors undergo an extensive examination program. These examinations should be as safe, gentle, and patient friendly as possible. To compare computed tomography angiography (CTA) and an extensive magnetic resonance imaging (MRI) protocol without contrast agents......: (sensitivity60%/specifivity100%/accuracy 93%/Kappa = 0.72/P = 1), whereas CTA showed: (sensitivity 40%/specificity 96%/accuracy 87% Kappa = 0.43/P = 1). CONCLUSIONS: In conclusion, an optimized MRI protocol that includes noncontrast-enhanced magnetic resonance angiography can be substituted for CTA...

  20. Forearm Muscle Volumes Can Be Accurately Quantified From High Resolution Magnetic Resonance Imaging (MRI)

    Science.gov (United States)

    Eng, Carolyn M.; Abrams, Geoff D.; Smallwood, Laura R.; Lieber, Richard L.; Ward, Samuel R.

    2007-01-01

    Upper extremity musculoskeletal modeling is becoming increasingly sophisticated, creating a growing need for subject-specific muscle size parameters. One method for determining subject-specific muscle volume is magnetic resonance imaging (MRI). The purpose of this study was to determine the validity of MRI-derived muscle volumes in the human forearm across a variety of muscle sizes and shapes. Seventeen cadaveric forearms were scanned using a fast spoiled gradient echo pulse sequence with high isotropic spatial resolution (1 mm3 voxels) on a 3T MR system. Pronator teres (PT), extensor carpi radialis brevis (ECRB), extensor pollicis longus (EPL), flexor carpi ulnaris (FCU), and brachioradialis (BR) muscles were manually segmented allowing volume to be calculated. Forearms were then dissected, muscles isolated, and muscle masses obtained, which allowed computation of muscle volume. Intraclass correlation coefficients (ICC2,1) and absolute volume differences were used to compare measurement methods. There was excellent agreement between the anatomical and MRI-derived muscle volumes (ICC = 0.97, relative error = 12.8%) when all 43 muscles were considered together. When individual muscles were considered, there was excellent agreement between measurement methods for PT (ICC = 0.97, relative error = 8.4%), ECRB (ICC = 0.93, relative error = 7.7%), and FCU (ICC = 0.91, relative error = 9.8%), and fair agreement for EPL (ICC = 0.68, relative error = 21.6%) and BR (ICC = 0.93, relative error = 17.2%). Thus, while MRI-based measurements of muscle volume produce relatively small errors in some muscles, muscles with high surface area-to-volume ratios may predispose them to segmentation error, and, therefore, the accuracy of these measurements may be unacceptable. PMID:17521657

  1. COMPET: High resolution high sensitivity MRI compatible pre-clinical PET scanner

    CERN Document Server

    Hines, Kim-Eigard; Skretting, Arne; Rohne, Ole; Bjaalie, Jan G; Volgyes, David; Rissi, Michael; Dorholt, Ole; Stapnes, Steinar

    2013-01-01

    COMPET is a pre-clinical MRI compatible PET scanner which decouples sensitivity and resolution by the use of a novel detector design. The detector has been built using 8 x 8 cm(2) square layers consisting of 30 LYSO crystals (2 x 3 x 80 mm(2)) interleaved with 24 Wavelength Shifting Fibers (WLS) (3 x 1 x 80 mm(3)). By stacking several layers into a module, the point-of-interaction (POI) can be measured in 3D. Four layers form a PET ring where the sensitivity can be increased by stacking several layers. The layers can be stacked so that no inter-crystal or inter-module gap is formed. COMPET has used four assembled layers for module and scanner characterization. The modules are connected to the COMPET data-acquisition chain and the reconstructed images are produced with the novel geometry-independent COMPET image reconstruction algorithm. Time and energy resolution have been resolved and found to be around 4 as and 14% respectively. Tests for MRI interference and count rate performance have been carried out The...

  2. High-resolution functional MRI of the human amygdala at 7 T

    Energy Technology Data Exchange (ETDEWEB)

    Sladky, Ronald, E-mail: ronald.sladky@meduniwien.ac.at [MR Centre of Excellence, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna (Austria); Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria); Baldinger, Pia; Kranz, Georg S. [Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria); Tröstl, Jasmin [MR Centre of Excellence, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna (Austria); Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria); Höflich, Anna; Lanzenberger, Rupert [Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria); Moser, Ewald [MR Centre of Excellence, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna (Austria); Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria); Windischberger, Christian, E-mail: christian.windischberger@meduniwien.ac.at [MR Centre of Excellence, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna (Austria); Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna (Austria)

    2013-05-15

    Functional magnetic resonance imaging (fMRI) has become the primary non-invasive method for investigating the human brain function. With an increasing number of ultra-high field MR systems worldwide possibilities of higher spatial and temporal resolution in combination with increased sensitivity and specificity are expected to advance detailed imaging of distinct cortical brain areas and subcortical structures. One target region of particular importance to applications in psychiatry and psychology is the amygdala. However, ultra-high field magnetic resonance imaging of these ventral brain regions is a challenging endeavor that requires particular methodological considerations. Ventral brain areas are particularly prone to signal losses arising from strong magnetic field inhomogeneities along susceptibility borders. In addition, physiological artifacts from respiration and cardiac action cause considerable fluctuations in the MR signal. Here we show that, despite these challenges, fMRI data from the amygdala may be obtained with high temporal and spatial resolution combined with increased signal-to-noise ratio. Maps of neural activation during a facial emotion discrimination paradigm at 7 T are presented and clearly show the gain in percental signal change compared to 3 T results, demonstrating the potential benefits of ultra-high field functional MR imaging also in ventral brain areas.

  3. High-resolution functional MRI of the human amygdala at 7 T

    Science.gov (United States)

    Sladky, Ronald; Baldinger, Pia; Kranz, Georg S.; Tröstl, Jasmin; Höflich, Anna; Lanzenberger, Rupert; Moser, Ewald; Windischberger, Christian

    2013-01-01

    Functional magnetic resonance imaging (fMRI) has become the primary non-invasive method for investigating the human brain function. With an increasing number of ultra-high field MR systems worldwide possibilities of higher spatial and temporal resolution in combination with increased sensitivity and specificity are expected to advance detailed imaging of distinct cortical brain areas and subcortical structures. One target region of particular importance to applications in psychiatry and psychology is the amygdala. However, ultra-high field magnetic resonance imaging of these ventral brain regions is a challenging endeavor that requires particular methodological considerations. Ventral brain areas are particularly prone to signal losses arising from strong magnetic field inhomogeneities along susceptibility borders. In addition, physiological artifacts from respiration and cardiac action cause considerable fluctuations in the MR signal. Here we show that, despite these challenges, fMRI data from the amygdala may be obtained with high temporal and spatial resolution combined with increased signal-to-noise ratio. Maps of neural activation during a facial emotion discrimination paradigm at 7 T are presented and clearly show the gain in percental signal change compared to 3 T results, demonstrating the potential benefits of ultra-high field functional MR imaging also in ventral brain areas. PMID:22138120

  4. High-resolution MRI of the ulnar and radial collateral ligaments of the wrist.

    Science.gov (United States)

    Nozaki, Taiki; Wu, Wei Der; Kaneko, Yasuhito; Rafijah, Gregory; Yang, Lily; Hitt, Dave; Yoshioka, Hiroshi

    2017-12-01

    Background Accurate diagnosis of injuries to the collateral ligaments of the wrist is technically challenging on MRI. Purpose To investigate usefulness of high-resolution two-dimensional (2D) and isotropic three-dimensional (3D) magnetic resonance imaging (MRI) for identifying and classifying the morphology of the ulnar and radial collateral ligaments (UCL and RCL) of the wrist. Material and Methods Thirty-seven participants were evaluated using 3T coronal 2D and isotropic 3D images by two radiologists independently. The UCL was classified into four types: 1a, narrow attachment to the tip of the ulnar styloid (Tip); 1b, broad attachment to the Tip; 2a, narrow attachment to the medial base of the ulnar styloid (Base); and 2b, broad attachment to the Base. The RCL was also classified into four types: 1a, separate radioscaphoid and scaphotrapezial ligaments (RS + ST) with narrow scaphoid attachment; 1b, RS + ST with broad scaphoid attachment; 2a, continuous radio-scapho-trapezial ligaments (RST) with narrow scaphoid attachment; and 2b, RST with broad scaphoid attachment. The inter-observer reliability of these classifications was calculated. Results Type 1a was the most common of both collateral ligaments. Of UCL classifications, 31.4% were revised after additional review of multiplanar reconstruction (MPR) images from isotropic data. The inter-observer reliability of UCL classification was substantial (k = 0.62) without MPR, and almost perfect (k = 0.84) with MPR. The inter-observer reliability of RCL classification was almost perfect (k = 0.89). Anatomic delineation between the two sequences was not statistically different. Conclusion The UCL and RCL were each identified on high-resolution 2D and isotropic 3D MRI equally well. MPR allows accurate identification of the UCL attachment to the ulnar styloid.

  5. BLIPPED (BLIpped Pure Phase EncoDing) high resolution MRI with low amplitude gradients

    Science.gov (United States)

    Xiao, Dan; Balcom, Bruce J.

    2017-12-01

    MRI image resolution is proportional to the maximum k-space value, i.e. the temporal integral of the magnetic field gradient. High resolution imaging usually requires high gradient amplitudes and/or long spatial encoding times. Special gradient hardware is often required for high amplitudes and fast switching. We propose a high resolution imaging sequence that employs low amplitude gradients. This method was inspired by the previously proposed PEPI (π Echo Planar Imaging) sequence, which replaced EPI gradient reversals with multiple RF refocusing pulses. It has been shown that when the refocusing RF pulse is of high quality, i.e. sufficiently close to 180°, the magnetization phase introduced by the spatial encoding magnetic field gradient can be preserved and transferred to the following echo signal without phase rewinding. This phase encoding scheme requires blipped gradients that are identical for each echo, with low and constant amplitude, providing opportunities for high resolution imaging. We now extend the sequence to 3D pure phase encoding with low amplitude gradients. The method is compared with the Hybrid-SESPI (Spin Echo Single Point Imaging) technique to demonstrate the advantages in terms of low gradient duty cycle, compensation of concomitant magnetic field effects and minimal echo spacing, which lead to superior image quality and high resolution. The 3D imaging method was then applied with a parallel plate resonator RF probe, achieving a nominal spatial resolution of 17 μm in one dimension in the 3D image, requiring a maximum gradient amplitude of only 5.8 Gauss/cm.

  6. Vasa previa evaluated by noncontrast time-of-flight magnetic resonance angiography.

    Science.gov (United States)

    Iwahashi, Naoyuki; Ota, Nami; Shiro, Michihisa; Yagi, Shigetaka; Minami, Sawako; Ino, Kazuhiko

    2016-08-01

    Vasa previa is a rare complication, and rupture of vasa previa during pregnancy may lead to significant perinatal mortality. Here, we report a case of vasa previa evaluated prenatally using noncontrast time-of-flight magnetic resonance angiography (TOF MRA). A 22-year-old primiparous woman was referred to our hospital due to suspicion of vasa previa. Transvaginal ultrasonography showed two vessels running over the internal os. To obtain further information, magnetic resonance imaging (MRI) and TOF MRA were performed. Caesarean section was carried out, and macroscopic findings of the vascular distribution on the fetal membrane were consistent with those identified by TOF MRA. TOF MRA in addition to MRI may be an option for prenatal identification of the precise three-dimensional vascular distribution in patients with vasa previa. Copyright © 2016. Published by Elsevier B.V.

  7. Analysis of trabecular bone structure in the distal radius using high-resolution MRI

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, S. [Magnetic Resonance Science Center and Musculoskeletal Section, Dept. of Radiology, Univ. of California, San Francisco, CA (United States); Genant, H.K. [Magnetic Resonance Science Center and Musculoskeletal Section, Dept. of Radiology, Univ. of California, San Francisco, CA (United States); Grampp, S. [Magnetic Resonance Science Center and Musculoskeletal Section, Dept. of Radiology, Univ. of California, San Francisco, CA (United States); Jergas, M.D. [Magnetic Resonance Science Center and Musculoskeletal Section, Dept. of Radiology, Univ. of California, San Francisco, CA (United States); Newitt, D.C. [Magnetic Resonance Science Center and Musculoskeletal Section, Dept. of Radiology, Univ. of California, San Francisco, CA (United States); Gies, A.A. [Magnetic Resonance Science Center and Musculoskeletal Section, Dept. of Radiology, Univ. of California, San Francisco, CA (United States)

    1994-12-01

    The objective of this study was to develop high-resolution in vivo magnetic resonance techniques to resolve the structure of trabecular bone in conjunction with image processing techniques to quantify variations in trabecular bone structure. Such techniques could then potentially be applied to assess osteoporotic changes and predict the risk fractures. Axial and coronal volumetric MRI images of the distal radius were obtained using a modified gradient echo sequence on a 1.5 T imager, at a spatial resolution of {approx} 150 {mu}m and a slice thickness of 0.7 mm. Image thresholding techniques were used to identify trabecular bone and bone marrow; thereafter the area occupied by trabecular bone, mean trabecular width and mean intercept length as a function of angle were computed. An automatic boundary tracking algorithm was used to identify the bone and marrow interface. Fractal analysis was used to quantify the convolutedness of the marrow-trabecular bone interface. It is well known that the trabecular bone density is the greater at distal sites of the radius and decreases proximally. These variations were reflected by the decreases in the trabecular width, fractional area and fractal dimension. Over a 28 mm range, starting at 7 mm proximal from the joint line and extending 35 mm proximal to the joint line, the mean trabecular width decreased from 444.6 {mu}m to 341.6 {mu}m, the fractional area of trabecular bone decreased from 0.44 to 0.15, and the fractal dimension decreased from 1.67 to 1.10. The choice of the threshold affected the quantification of the mean trabecular width and fractional trabecular bone area measurements, but the fractal dimension was more robust. High-resolution MRI images combined with image analysis techniques can be used to quantify structural variations in trabecular bone in the distal radius. (orig.)

  8. Branch Atheromatous Plaque: A Major Cause of Lacunar Infarction (High-Resolution MRI Study

    Directory of Open Access Journals (Sweden)

    Jong-Won Chung

    2012-07-01

    Full Text Available Background: Lacunar infarctions account for up to 25% of all ischemic strokes and, thus, constitute a numerically important subgroup. It is important that the two pathogeneses of lacunar infarction, that is, small-vessel occlusion and branch atheromatous disease, be differentiated because prognoses and treatment strategies differ. The authors evaluated the presence of branch atheromatous plaque in parent arteries that supply lacunar infarcts by high-resolution magnetic resonance imaging (HR-MRI. Methods: HR-MRI was performed in 15 patients with (1 a clinical presentation consistent with classical lacunar syndromes; (2 an acute lacunar infarction by diffusion-weighted imaging, measuring ≤20 mm in maximal diameter; (3 a magnetic resonance angiography showing a normal middle cerebral artery or basilar artery supplying the ischemic lesion, and (4 no other obvious etiology for small-vessel distribution ischemic stroke. Results: The median time of vessel wall imaging after index events was 4 days (range, 2–15 days. Six of the 15 patients had a lacunar infarction in the middle cerebral artery territory, and 9 had a lesion in the basilar artery territory. HR-MRI detected underlying atheromatous plaques in 9 patients (60% with a lacunar infarction. In these 9 patients, asymptomatic intracranial atherosclerotic stenosis was more frequent compared to patients without branch atheromatous plaque (55.6 vs. 16.7%. In pontine infarctions, ischemic lesions that extended to the pial base of the pons were more frequent in patients with branch atheromatous plaques (83.3 vs. 33.3%, and all the ischemic lesions and atheromatous plaques were on the same side (right, n = 2; left, n = 4. All plaques responsible for acute symptomatic lacunar infarction were enhanced in contrast-enhanced T1-weighted HR-MR images. Conclusions: HR-MRI results enabled underlying symptomatic branch atheromatous disease to be detected in lacunar infarction patients. The experience gained

  9. Role of pharmacokinetic parameters derived with high temporal resolution DCE MRI using simultaneous PET/MRI system in breast cancer: A feasibility study.

    Science.gov (United States)

    Jena, Amarnath; Taneja, Sangeeta; Singh, Aru; Negi, Pradeep; Mehta, Shashi Bhushan; Sarin, Ramesh

    2017-01-01

    To evaluate the reliability of pharmacokinetic parameters like K(trans), Kep and ve derived through DCE MRI breast protocol using 3T Simultaneous PET/MRI (3Tesla Positron Emission Tomography/Magnetic Resonance Imaging) system in distinguishing benign and malignant lesions. High temporal resolution DCE (Dynamic Contrast Enhancement) MRI performed as routine breast MRI for diagnosis or as a part of PET/MRI for cancer staging using a 3T simultaneous PET/MRI system in 98 women having 109 breast lesions were analyzed for calculation of pharmacokinetic parameters (K(trans), ve, and Kep) at 60s time point using an in-house developed computation scheme. Receiver operating characteristic (ROC) curve analysis revealed a cut off value for K(trans), Kep, ve as 0.50, 2.59, 0.15 respectively which reliably distinguished benign and malignant breast lesions. Data analysis revealed an overall accuracy of 94.50%, 79.82% and 87.16% for K(trans), Kep, ve respectively. Introduction of native T1 normalization with an externally placed phantom showed a higher accuracy (94.50%) than without native T1 normalization (93.50%) with an increase in specificity of 87% vs 84%. Overall the results indicate that reliable measurement of pharmacokinetic parameters with reduced acquisition time is feasible in a 3TMRI embedded PET/MRI system with reasonable accuracy and application may be extended to exploit the potential of simultaneous PET/MRI in further work on breast cancer. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Resolution improvement of brain PET images using prior information from MRI: clinical application on refractory epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Silva-Rodríguez, Jesus [Instituto de Investigaciones Sanitarias (IDIS), Santiago de Compostela (Spain); Tsoumpas, Charalampos [University of Leeds, Leeds (United Kingdom); Aguiar, Pablo; Cortes, Julia [Nuclear Medicine Department, University Hospital (CHUS), Santiago de Compostela (Spain); Urdaneta, Jesus Lopez [Instituto de Investigaciones Sanitarias (IDIS), Santiago de Compostela (Spain)

    2015-05-18

    An important counterpart of clinical Positron Emission Tomography (PET) for early diagnosis of neurological diseases is its low resolution. This is particularly important when evaluating diseases related to small hypometabolisms such as epilepsy. The last years, new hybrid systems combining PET with Magnetic Resonance (MR) has been increasingly used for several different clinical applications. One of the advantages of MR is the production of high spatial resolution images and a potential application of PET-MR imaging is the improvement of PET resolution using MR information. A potential advantage of resolution recovery of PET images is the enhancement of contrast delivering at the same time better detectability of small lesions or hypometabolic areas and more accurate quantification over these areas. Recently, Shidahara et al (2009) proposed a new method using wavelet transforms in order to produce PET images with higher resolution. We optimised Shidahara’s method (SFS-RR) to take into account possible shortcomings on the particular clinical datasets, and applied it to a group of patients diagnosed with refractory epilepsy. FDG-PET and MRI images were acquired sequentially and then co-registered using software tools. A complete evaluation of the PET/MR images was performed before and after the correction, including different parameters related with PET quantification, such as atlas-based metabolism asymmetry coefficients and Statistical Parametric Mapping results comparing to a database of 87 healthy subjects. Furthermore, an experienced physician analyzed the results of non-corrected and corrected images in order to evaluate improvements of detectability on a visual inspection. Clinical outcome was used as a gold standard. SFS-RR demonstrated to have a positive impact on clinical diagnosis of small hypometabolisms. New lesions were detected providing additional clinically relevant information on the visual inspection. SPM sensitivity for the detection of small

  11. High Spatial Resolution MRI of Cystic Adventitial Disease of the Iliofemoral Vein Communicating with the Hip Joint

    Energy Technology Data Exchange (ETDEWEB)

    Michaelides, Michael, E-mail: mihalismihailidis@gmail.com [Ygia Polyclinic Hospital, MRI/CT Department (Cyprus); Papas, Stylianos, E-mail: vascular@drpapas.com [Ygia Polyclinic Hospital, Vascular Surgery Department (Cyprus); Pantziara, Maria, E-mail: mgpantziara@gmail.com; Ioannidis, Kleanthis, E-mail: aktinodiagnostis@gmail.com [Ygia Polyclinic Hospital, MRI/CT Department (Cyprus)

    2013-05-14

    Venous cystic adventitial disease (CAD) is an extremely rare entity, and so far less than 20 cases have been described in the literature. Herein, we describe the imaging findings of CAD of iliofemoral vein in a 51-year-old woman who presented with leg swelling with special emphasis on high spatial resolution MRI, which demonstrated communication of the cyst with the hip joint. To our knowledge, this is the first description of high spatial resolution MRI findings in venous CAD supporting a new theory about the pathogenesis of venous CAD.

  12. High spatial resolution MRI of cystic adventitial disease of the iliofemoral vein communicating with the hip joint.

    Science.gov (United States)

    Michaelides, Michael; Papas, Stylianos; Pantziara, Maria; Ioannidis, Kleanthis

    2014-02-01

    Venous cystic adventitial disease (CAD) is an extremely rare entity, and so far less than 20 cases have been described in the literature. Herein, we describe the imaging findings of CAD of iliofemoral vein in a 51-year-old woman who presented with leg swelling with special emphasis on high spatial resolution MRI, which demonstrated communication of the cyst with the hip joint. To our knowledge, this is the first description of high spatial resolution MRI findings in venous CAD supporting a new theory about the pathogenesis of venous CAD.

  13. Direct comparison of high‐temporal‐resolution CINE MRI with Doppler ultrasound for assessment of diastolic dysfunction in mice

    Science.gov (United States)

    Price, Anthony N.; Jackson, Laurence H.; Taylor, Valerie; David, Anna L.; Lythgoe, Mark F.; Stuckey, Daniel J.

    2017-01-01

    Diastolic dysfunction is a sensitive early indicator of heart failure and can provide additional data to conventional measures of systolic function. Transmitral Doppler ultrasound, which measures the one‐dimensional flow of blood through the mitral valve, is currently the preferred method for the measurement of diastolic function, but the measurement of the left ventricular volume changes using high‐temporal‐resolution cinematic magnetic resonance imaging (CINE MRI) is an alternative approach which is emerging as a potentially more robust and user‐independent technique. Here, we investigated the performance of high‐temporal‐resolution CINE MRI and compared it with ultrasound for the detection of diastolic dysfunction in a mouse model of myocardial infarction. An in‐house, high‐temporal‐resolution, retrospectively gated CINE sequence was developed with a temporal resolution of 1 ms. Diastolic function in mice was assessed using a custom‐made, open‐source reconstruction package. Early (E) and late (A) left ventricular filling phases were easily identifiable, and these measurements were compared directly with high‐frequency, pulsed‐wave, Doppler ultrasound measurements of mitral valve inflow. A repeatability study established that high‐temporal‐resolution CINE MRI and Doppler ultrasound showed comparable accuracy when measuring E/A in normal control mice. However, when applied in a mouse model of myocardial infarction, high‐temporal‐resolution CINE MRI indicated diastolic heart failure (E/A = 0.94 ± 0.11), whereas ultrasound falsely detected normal cardiac function (E/A = 1.21 ± 0.11). The addition of high‐temporal‐resolution CINE MRI to preclinical imaging studies enhances the library of sequences available to cardiac researchers and potentially identifies diastolic heart failure early in disease progression. PMID:28643891

  14. Direct comparison of high-temporal-resolution CINE MRI with Doppler ultrasound for assessment of diastolic dysfunction in mice.

    Science.gov (United States)

    Roberts, Thomas A; Price, Anthony N; Jackson, Laurence H; Taylor, Valerie; David, Anna L; Lythgoe, Mark F; Stuckey, Daniel J

    2017-10-01

    Diastolic dysfunction is a sensitive early indicator of heart failure and can provide additional data to conventional measures of systolic function. Transmitral Doppler ultrasound, which measures the one-dimensional flow of blood through the mitral valve, is currently the preferred method for the measurement of diastolic function, but the measurement of the left ventricular volume changes using high-temporal-resolution cinematic magnetic resonance imaging (CINE MRI) is an alternative approach which is emerging as a potentially more robust and user-independent technique. Here, we investigated the performance of high-temporal-resolution CINE MRI and compared it with ultrasound for the detection of diastolic dysfunction in a mouse model of myocardial infarction. An in-house, high-temporal-resolution, retrospectively gated CINE sequence was developed with a temporal resolution of 1 ms. Diastolic function in mice was assessed using a custom-made, open-source reconstruction package. Early (E) and late (A) left ventricular filling phases were easily identifiable, and these measurements were compared directly with high-frequency, pulsed-wave, Doppler ultrasound measurements of mitral valve inflow. A repeatability study established that high-temporal-resolution CINE MRI and Doppler ultrasound showed comparable accuracy when measuring E/A in normal control mice. However, when applied in a mouse model of myocardial infarction, high-temporal-resolution CINE MRI indicated diastolic heart failure (E/A = 0.94 ± 0.11), whereas ultrasound falsely detected normal cardiac function (E/A = 1.21 ± 0.11). The addition of high-temporal-resolution CINE MRI to preclinical imaging studies enhances the library of sequences available to cardiac researchers and potentially identifies diastolic heart failure early in disease progression. © 2017 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.

  15. NON-CONTRAST MAGNETIC RESONANCE UROGRAPHY

    Directory of Open Access Journals (Sweden)

    Arpita C

    2016-07-01

    Full Text Available BACKGROUND AND PURPOSE Magnetic Resonance (MR urography with its optimal contrast resolution and lack of ionizing radiation provides a comprehensive examination of the entire urinary tract noninvasively. MR urography is clinically useful in the evaluation of suspected urinary tract obstruction, haematuria, congenital anomalies, and surgically altered anatomy. It is particularly useful in cases of where there is contraindication of ionizing radiation and in paediatric and pregnant patients. The common MR urographic techniques are: Static-fluid MR urography and excretory MR urography. Static-fluid MR urography uses of heavily T2-weighted sequences to image the urinary tract as a static collection of fluid, can be repeated sequentially (Cine MR urography to better demonstrate the ureters in their entirety and to confirm the presence of fixed stenoses. Excretory MR urography is performed during the excretory phase of enhancement after the intravenous administration of gadolinium-based contrast material; thus, the patient must have sufficient renal function to allow the excretion. Static-fluid and excretory MR urography can be combined with conventional MR imaging for comprehensive evaluation of the urinary tract. The limitations are limited availability, high cost, relatively long examination time, low spatial resolution compared to IVU (Intravenous Urogram and CT Urography; sensitivity to motion (breathing and ureteral peristalsis inherent contraindications like patients with pacemakers, claustrophobia, and relative insensitivity for calcification and ureteric calculi. In this article, an attempt has been made to demonstrate the potential of static-fluid MRU to demonstrate a spectrum of urologic pathology involving the kidneys, ureters, and bladder while discussing the limitations. METHODS Thirty patients with urinary tract abnormalities were evaluated with MR urography performed between May 2014 to April 2016 using routine MR sequences and

  16. Tradeoffs in pushing the spatial resolution of fMRI for the 7T Human Connectome Project.

    Science.gov (United States)

    T Vu, An; Jamison, Keith; Glasser, Matthew F; Smith, Stephen M; Coalson, Timothy; Moeller, Steen; Auerbach, Edward J; Uğurbil, Kamil; Yacoub, Essa

    2017-07-01

    Whole-brain functional magnetic resonance imaging (fMRI), in conjunction with multiband acceleration, has played an important role in mapping the functional connectivity throughout the entire brain with both high temporal and spatial resolution. Ultrahigh magnetic field strengths (7T and above) allow functional imaging with even higher functional contrast-to-noise ratios for improved spatial resolution and specificity compared to traditional field strengths (1.5T and 3T). High-resolution 7T fMRI, however, has primarily been constrained to smaller brain regions given the amount of time it takes to acquire the number of slices necessary for high resolution whole brain imaging. Here we evaluate a range of whole-brain high-resolution resting state fMRI protocols (0.9, 1.25, 1.5, 1.6 and 2mm isotropic voxels) at 7T, obtained with both in-plane and slice acceleration parallel imaging techniques to maintain the temporal resolution and brain coverage typically acquired at 3T. Using the processing pipeline developed by the Human Connectome Project, we demonstrate that high resolution images acquired at 7T provide increased functional contrast to noise ratios with significantly less partial volume effects and more distinct spatial features, potentially allowing for robust individual subject parcellations and descriptions of fine-scaled patterns, such as visuotopic organization. Published by Elsevier Inc.

  17. The Effect of Spatial and Temporal Resolution of Cine Phase Contrast MRI on Wall Shear Stress and Oscillatory Shear Index Assessment

    NARCIS (Netherlands)

    Cibis, Merih; Potters, Wouter V.; Gijsen, Frank J.; Marquering, Henk; van Ooij, Pim; VanBavel, Ed; Wentzel, Jolanda J.; Nederveen, Aart J.

    2016-01-01

    Introduction Wall shear stress (WSS) and oscillatory shear index (OSI) are associated with atherosclerotic disease. Both parameters are derived from blood velocities, which can be measured with phase-contrast MRI (PC-MRI). Limitations in spatiotemporal resolution of PC-MRI are known to affect these

  18. Influence of field strength, coil type and image resolution on assessment of synovitis by unenhanced MRI - a comparison with contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Eshed, Iris [The Sheba Medical Center, Department of Diagnostic Imaging, Tel Hashomer (Israel); Tel Aviv University, Sackler School of Medicine, Tel Aviv (Israel); Krabbe, Simon; Axelsen, Mette; Pedersen, Susanne Juhl [Copenhagen University Hospital Glostrup, Copenhagen Center for Arthritis Research, Center for Rheumatology and Spine Diseases, Copenhagen (Denmark); Oestergaard, Mikkel [Copenhagen University Hospital Glostrup, Copenhagen Center for Arthritis Research, Center for Rheumatology and Spine Diseases, Copenhagen (Denmark); Copenhagen University Hospital Gentofte, Department of Rheumatology/C, Copenhagen (Denmark); Boeyesen, Pernille [Diakonhjemmet Hospital, Department of Rheumatology, Oslo (Norway); Moeller, Jakob M. [Copenhagen University Hospital at Herlev, Department of Radiology, Copenhagen (Denmark); Therkildsen, Flemming [Metropolitan University College, Copenhagen (Denmark); Madsen, Ole Rintek [Copenhagen University Hospital Gentofte, Department of Rheumatology/C, Copenhagen (Denmark)

    2015-04-01

    To explore if the reliability of synovitis assessment by unenhanced MRI is influenced by different MRI field-strengths, coil types and image resolutions in RA patients. Forty-one RA patients and 12 healthy controls underwent hand MRI (wrist and 2{sup nd}-5{sup th} metacarpophalangeal joints) at 4 different field-strengths (0.23 T/0.6 T/1.5 T/3.0 T) on the same day. Seven protocols using a STIR sequence with different field-strengths, coils (flex coils/dedicated phased-array extremity coils) and resolution were applied and scored blindly for synovitis (OMERACT-RAMRIS method). A 1.5 T post-contrast T1-weighted sequence was used as gold standard reference. Fair-good agreement (ICC=0.38-0.72) between the standard reference and the different STIR protocols (best agreement with extremity coil and small voxel size at 1.5 T). The accuracy for presence/absence of synovitis was very high per person (0.80-1.0), and moderate-high per joint (0.63-0.85), whereas exact agreements on scores were moderate (0.50-0.66). The intrareader agreement (15 patients and 3 controls) on presence/absence of synovitis was very high (0.87-1.0). Unenhanced MRI using STIR sequence is only moderately reliable for assessing hand synovitis in RA, when contrast-enhanced MRI is considered the gold standard reference. Contrast injection, field strength and coil type influence synovitis assessment, and should be considered before performing MRI in clinical trials and practice. (orig.)

  19. Three-Dimensional CAIPIRINHA SPACE TSE for 5-Minute High-Resolution MRI of the Knee.

    Science.gov (United States)

    Fritz, Jan; Fritz, Benjamin; Thawait, Gaurav G; Meyer, Heiko; Gilson, Wesley D; Raithel, Esther

    2016-10-01

    The aim of this study was to prospectively test the hypothesis that a 2-dimensional (2D) CAIPIRINHA (controlled aliasing in parallel imaging results in higher acceleration) sampling pattern facilitates 5-minute high spatial resolution 3-dimensional (3D) sampling perfection with application optimized contrast using different flip angle evolutions (SPACE) magnetic resonance imaging (MRI) of the knee with image quality similar or better than current 2D turbo spin echo (TSE) and 3D SPACE standards. The study was approved by our institutional review board. Twenty asymptomatic subjects (12 men, 8 women; mean age, 42 years; age range, 24-65 years) underwent 3 T MRI of the knee. A 4-fold accelerated 3D SPACE TSE prototype with 2D CAIPIRINHA sampling pattern and 5-minute acquisition time was compared with commercially available 2-fold and 4-fold accelerated 3D SPACE and 2D TSE pulse sequences with acquisition times of 11 minutes and 15 seconds, 6 minutes and 30 seconds, as well as 9 minutes and 48 seconds, respectively. Outcome variables included image quality, anatomic visibility, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). Statistical analysis included Friedman, repeated measures analysis of variances, and Cohen's weighted κ tests. Bonferroni-corrected P values of 0.005 and less were considered statistically significant. Overall, image quality, visibility of anatomic structures, SNR, and CNR of 3D CAIPIRINHA SPACE were statistically similar to 2-fold accelerated 3D SPACE and significantly better than 4-fold accelerated 3D SPACE, which exhibited degrading parallel imaging artifacts. Compared with 2.5-mm 2D TSE images, 0.5-mm 3D CAIPIRINHA SPACE images showed statistically similar good edge sharpness and very good contrast resolution, and significantly less partial volume as well as absent chemical shift and pulsatile flow artifacts. Visibility of menisci, anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament, and lateral

  20. A linear algorithm of the reference region model for DCE-MRI is robust and relaxes requirements for temporal resolution.

    Science.gov (United States)

    Cárdenas-Rodríguez, Julio; Howison, Christine M; Pagel, Mark D

    2013-05-01

    Dynamic contrast enhanced MRI (DCE-MRI) has utility for improving clinical diagnoses of solid tumors, and for evaluating the early responses of anti-angiogenic chemotherapies. The Reference Region Model (RRM) can improve the clinical implementation of DCE-MRI by substituting the contrast enhancement of muscle for the Arterial Input Function that is used in traditional DCE-MRI methodologies. The RRM is typically fitted to experimental results with a non-linear least squares algorithm. This report demonstrates that this algorithm produces inaccurate and imprecise results when DCE-MRI results have low SNR or slow temporal resolution. To overcome this limitation, a linear least-squares algorithm has been derived for the Reference Region Model. This new algorithm improves accuracy and precision of fitting the Reference Region Model to DCE-MRI results, especially for voxel-wise analyses. This linear algorithm is insensitive to injection speeds, and has 300- to 8000-fold faster calculation speed relative to the non-linear algorithm. The linear algorithm produces more accurate results for over a wider range of permeabilities and blood volumes of tumor vasculature. This new algorithm, termed the Linear Reference Region Model, has strong potential to improve clinical DCE-MRI evaluations. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. MRI data driven partial volume effects correction in PET imaging using 3D local multi-resolution analysis

    Energy Technology Data Exchange (ETDEWEB)

    Le Pogam, Adrien, E-mail: adrien.lepogam@univ-brest.fr [INSERM UMR 1101, LaTIM, Brest (France); Lamare, Frederic [Academic Nuclear Medicine Department, CHU Pellegrin, Bordeaux (France); Hatt, Mathieu [INSERM UMR 1101, LaTIM, Brest (France); Fernandez, Philippe [Academic Nuclear Medicine Department, CHU Pellegrin, Bordeaux (France); Le Rest, Catherine Cheze [INSERM UMR 1101, LaTIM, Brest (France); Academic Nuclear Medicine Department, CHU Poitiers, Poitiers (France); Visvikis, Dimitris [INSERM UMR 1101, LaTIM, Brest (France)

    2013-02-21

    PET partial volume effects (PVE) resulting from the limited resolution of PET scanners is still a quantitative issue that PET/MRI scanners do not solve by themselves. A recently proposed voxel-based locally adaptive 3D multi-resolution PVE correction based on the mutual analysis of wavelet decompositions was applied on 12 clinical {sup 18}F-FLT PET/T1 MRI images of glial tumors, and compared to a PET only voxel-wise iterative deconvolution approach. Quantitative and qualitative results demonstrated the interest of exploiting PET/MRI information with higher uptake increases (19±8% vs. 11±7%, p=0.02), as well as more convincing visual restoration of details within tumors with respect to deconvolution of the PET uptake only. Further studies are now required to demonstrate the accuracy of this restoration with histopathological validation of the uptake in tumors.

  2. Noncontrast-Enhanced Magnetic Resonance Versus Computed Tomography Angiography in Preoperative Evaluation of Potential Living Renal Donors.

    Science.gov (United States)

    Blankholm, Anne Dorte; Pedersen, Bodil G; Østrat, Ernst Ø; Andersen, Gratien; Stausbøl-Grøn, Brian; Laustsen, Susse; Ringgaard, Steffen

    2015-11-01

    Living renal donors undergo an extensive examination program. These examinations should be as safe, gentle, and patient friendly as possible. To compare computed tomography angiography (CTA) and an extensive magnetic resonance imaging (MRI) protocol without contrast agents to observations from nephrectomy in living renal donors and to evaluate whether noncontrast-enhanced MRI can replace CTA for vessel assessment in living renal donors. CTA and MRI results were compared to observations from nephrectomy, which served as the reference standard. Fifty-one potential kidney donors underwent imaging, and 31 donated a kidney. Comparisons in sensitivity, specificity, and accuracy were made with respect to the number of arteries, early branching, and the number of veins. Agreement was assessed using Cohen's kappa. The exact McNemar's test was used to test for statistically significant differences. In the assessment of more than one renal artery, the sensitivity and specificity of MRI and CTA were high and in perfect agreement compared to observations from surgery. The results for both MRI and CTA were as follows: (sensitivity 100%/specificity100%/accuracy 100%/Kappa = 1/P = 1). When comparing the ability to test for early branching we found, MRI: (sensitivity 33%/specificity 100%/accuracy 87%/Kappa = 0.45/P = 1) and CTA: (sensitivity 50%/specificity 100%/accuracy 90%/Kappa = 0.62/P = 1). When used to depict supernumerary veins, we found MRI: (sensitivity60%/specifivity100%/accuracy 93%/Kappa = 0.72/P = 1), whereas CTA showed: (sensitivity 40%/specificity 96%/accuracy 87% Kappa = 0.43/P = 1). In conclusion, an optimized MRI protocol that includes noncontrast-enhanced magnetic resonance angiography can be substituted for CTA for preoperative assessment of the renal vessels before living donor nephrectomy. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  3. Quantification of hepatic blood flow using a high-resolution phase-contrast MRI sequence with compressed sensing acceleration.

    Science.gov (United States)

    Dyvorne, Hadrien A; Knight-Greenfield, Ashley; Besa, Cecilia; Cooper, Nancy; Garcia-Flores, Julio; Schiano, Thomas D; Markl, Michael; Taouli, Bachir

    2015-03-01

    OBJECTIVE. The objective of our study was to evaluate the performance of a high-spatial-resolution 2D phase-contrast (PC) MRI technique accelerated with compressed sensing for portal vein (PV) and hepatic artery (HA) flow quantification in comparison with a standard PC MRI sequence. SUBJECTS AND METHODS. In this prospective study, two PC MRI sequences were compared, one with parallel imaging acceleration and low spatial resolution (generalized autocalibrating partial parallel acquisition [GRAPPA]) and one with compressed sensing acceleration and high spatial resolution (sparse). Seventy-six patients were assessed, including 37 patients with cirrhosis. Two observers evaluated PC image quality. Quantitative analyses yielded a mean velocity, flow, and vessel area for the PV and HA and an arterial fraction. The PC techniques were compared using the paired Wilcoxon test and Bland-Altman statistics. The sensitivity of the flow parameters to the severity of cirrhosis was also assessed. RESULTS. Vessel delineation was significantly improved using the PC sparse sequence (p spatial-resolution highly accelerated compressed sensing technique (PC sparse) allows total hepatic blood flow measurements obtained in 1 breath-hold, provides improved delineation of the hepatic vessels compared with a standard PC MRI sequence (GRAPPA), and can potentially be used for the noninvasive assessment of liver cirrhosis.

  4. High-resolution whole-brain DCE-MRI using constrained reconstruction: Prospective clinical evaluation in brain tumor patients

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yi, E-mail: yiguo@usc.edu; Zhu, Yinghua; Lingala, Sajan Goud; Nayak, Krishna [Ming Hsieh Department of Electrical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California 90089 (United States); Lebel, R. Marc [GE Healthcare, Calgary, Alberta AB T2P 1G1 (Canada); Shiroishi, Mark S.; Law, Meng [Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033 (United States)

    2016-05-15

    Purpose: To clinically evaluate a highly accelerated T1-weighted dynamic contrast-enhanced (DCE) MRI technique that provides high spatial resolution and whole-brain coverage via undersampling and constrained reconstruction with multiple sparsity constraints. Methods: Conventional (rate-2 SENSE) and experimental DCE-MRI (rate-30) scans were performed 20 minutes apart in 15 brain tumor patients. The conventional clinical DCE-MRI had voxel dimensions 0.9 × 1.3 × 7.0 mm{sup 3}, FOV 22 × 22 × 4.2 cm{sup 3}, and the experimental DCE-MRI had voxel dimensions 0.9 × 0.9 × 1.9 mm{sup 3}, and broader coverage 22 × 22 × 19 cm{sup 3}. Temporal resolution was 5 s for both protocols. Time-resolved images and blood–brain barrier permeability maps were qualitatively evaluated by two radiologists. Results: The experimental DCE-MRI scans showed no loss of qualitative information in any of the cases, while achieving substantially higher spatial resolution and whole-brain spatial coverage. Average qualitative scores (from 0 to 3) were 2.1 for the experimental scans and 1.1 for the conventional clinical scans. Conclusions: The proposed DCE-MRI approach provides clinically superior image quality with higher spatial resolution and coverage than currently available approaches. These advantages may allow comprehensive permeability mapping in the brain, which is especially valuable in the setting of large lesions or multiple lesions spread throughout the brain.

  5. High-resolution MRI of cranial nerves in posterior fossa at 3.0 T.

    Science.gov (United States)

    Guo, Zi-Yi; Chen, Jing; Liang, Qi-Zhou; Liao, Hai-Yan; Cheng, Qiong-Yue; Fu, Shui-Xi; Chen, Cai-Xiang; Yu, Dan

    2013-02-01

    To evaluate the influence of high-resolution imaging obtainable with the higher field strength of 3.0 T on the visualization of the brain nerves in the posterior fossa. In total, 20 nerves were investigated on MRI of 12 volunteers each and selected for comparison, respectively, with the FSE sequences with 5 mm and 2 mm section thicknesses and gradient recalled echo (GRE) sequences acquired with a 3.0-T scanner. The MR images were evaluated by three independent readers who rated image quality according to depiction of anatomic detail and contrast with use of a rating scale. In general, decrease of the slice thickness showed a significant increase in the detection of nerves as well as in the image quality characteristics. Comparing FSE and GRE imaging, the course of brain nerves and brainstem vessels was visualized best with use of the three-dimensional (3D) pulse sequence. The comparison revealed the clear advantage of a thin section. The increased resolution enabled immediate identification of all brainstem nerves. GRE sequence most distinctly and confidently depicted pertinent structures and enables 3D reconstruction to illustrate complex relations of the brainstem. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  6. Spatial resolution and velocity field improvement of 4D-flow MRI.

    Science.gov (United States)

    Callaghan, Fraser M; Grieve, Stuart M

    2017-11-01

    4D-flow MRI obtains a time-dependent 3D velocity field; however, its use for the calculation of higher-order parameters is limited by noise. We present an algorithm for denoising 4D-flow data. By integrating a velocity field and eliminating streamlines in noisy flow, depicted by high curvature, a denoised dataset may be extracted. This method, defined as the velocity field improvement (VFIT) algorithm, was validated in an analytical dataset and using in vivo data in comparison with a computation fluid dynamics (CFD) simulation. As a proof of principal, wall shear stress (WSS) measurements in the descending aorta were compared with those defined by CFD. The VFIT algorithm achieved a >100% noise reduction of a corrupted analytical dataset. In addition, 4D-flow data were cleaned to show improved spatial resolution and near wall velocity representation. WSS measures compared well with CFD data and bulk flow dynamics were retained (flow measurements). This study presents a method for denoising 4D-flow datasets with improved spatial resolution. Bulk flow dynamics are accurately conserved while velocity and velocity gradient fields are improved; this is important in the calculation of higher-order parameters such as WSS, which are shown to be more comparable to CFD measures. Magn Reson Med 78:1959-1968, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  7. Hypothalamus as a mediator of chronic migraine: Evidence from high-resolution fMRI.

    Science.gov (United States)

    Schulte, Laura H; Allers, Angie; May, Arne

    2017-05-23

    To identify pathophysiologic mechanisms of migraine chronification using a recently standardized protocol for high-resolution brainstem imaging of trigeminal nociceptive stimulation. Eighteen episodic migraineurs (EMs), 17 chronic migraineurs (CMs), and 19 healthy controls (HCs) underwent painful ammonia stimulation of the left nostril in a 3T MRI scanner. Functional images were acquired with a brainstem-optimized protocol for high-resolution echo-planar imaging. We detected a significantly stronger activation of the anterior right hypothalamus in CMs compared to HCs. To exclude the headache as a prime mediator of the hypothalamic activations, we compared all migraineurs with headaches (EMs and CMs) with all migraineurs without headaches (EMs and CMs) and HCs in a second analysis and found a more posterior region of the hypothalamus to be more activated bilaterally during headaches. Our data corroborate the fact that the hypothalamus plays a crucial role in the pathophysiology of migraine chronification and acute pain stage of migraineurs. While the more posterior part of the hypothalamus seems to be important for the acute pain stage, the more anterior part seems to play an important role in attack generation and migraine chronification. © 2017 American Academy of Neurology.

  8. Prostate Cancer Detection Using High-Spatial Resolution MRI at 7.0 Tesla: Correlation with Histopathologic Findings at Radical Prostatectomy

    Science.gov (United States)

    2013-10-01

    Spatial Resolution MRI at 7.0 Tesla : Correlation with Histopathologic Findings at Radical Prostatectomy PRINCIPAL INVESTIGATOR: Andrew...Cancer Detection Using High-Spatial Resolution MRI at 7.0 Tesla : Correlation with Histopathologic Findings at Radical Prostatectomy 5a. CONTRACT...to achieve standard T2-weighted imaging for 7.0T prostate MRI. Specifically, we implemented a novel surface coil array in conjunction with

  9. High resolution MRI anatomy of the cat brain at 3 Tesla

    Science.gov (United States)

    Gray-Edwards, Heather L.; Salibi, Nouha; Josephson, Eleanor M.; Hudson, Judith A.; Cox, Nancy R.; Randle, Ashley N.; McCurdy, Victoria J.; Bradbury, Allison M.; Wilson, Diane U.; Beyers, Ronald J.; Denney, Thomas S.; Martin, Douglas R.

    2014-01-01

    Background Feline models of neurologic diseases, such as lysosomal storage diseases, leukodystrophies, Parkinson’s disease, stroke and NeuroAIDS, accurately recreate many aspects of human disease allowing for comparative study of neuropathology and the testing of novel therapeutics. Here we describe in vivo visualization of fine structures within the feline brain that were previously only visible post mortem. New Method 3 Tesla MR images were acquired using T1-weighted (T1w) 3D magnetization-prepared rapid gradient echo (MPRAGE) sequence (0.4mm isotropic resolution) and T2-weighted (T2w) turbo spin echo (TSE) images (0.3×0.3×1 mm3 resolution). Anatomic structures were identified based on feline and canine histology. Results T2w high resolution MR images with detailed structural identification are provided in transverse, sagittal and dorsal planes. T1w MR images are provided electronically in three dimensions for unrestricted spatial evaluation. Comparison with Existing Methods Many areas of the feline brain previously unresolvable on MRI are clearly visible in three orientations, including the dentate, interpositus and fastigial cerebellar nuclei, cranial nerves, lateral geniculate nucleus, optic radiation, cochlea, caudal colliculus, temporal lobe, precuneus, spinocerebellar tract, vestibular nuclei, reticular formation, pyramids and rostral and middle cerebral arteries. Additionally, the feline brain is represented in 3 dimensions for the first time. Conclusions These data establish normal appearance of detailed anatomical structures of the feline brain, which provide reference when evaluating neurologic disease or testing efficacy of novel therapeutics in animal models. PMID:24525327

  10. MRI

    Science.gov (United States)

    ... and radio waves to create pictures of the body. It does not use radiation (x-rays). Single MRI images are called slices. The images can be stored on a computer or printed on film. One exam produces dozens or sometimes hundreds of ...

  11. Evaluation of high-resolution In Vivo MRI for longitudinal analysis of endochondral fracture healing in mice

    Science.gov (United States)

    Müller-Graf, Fabian; Matthys, Romano; Hägele, Yvonne; Fischer, Verena; Jonas, René; Abaei, Alireza; Gebhard, Florian; Rasche, Volker; Ignatius, Anita

    2017-01-01

    Mice are extensively used for experimental bone-healing studies. However, there are few established nondestructive in vivo techniques for longitudinal fracture-healing analysis in mice, including in vivo micro-computed tomography (μCT) and radiography. Importantly, none of the established methods can discriminate between non-mineralized fibrous tissue and cartilage in the soft fracture callus. Therefore, the objective was to establish high-resolution in vivo magnetic resonance imaging (MRI) for the longitudinal assessment of soft callus formation during bone healing in mice. C57BL/6J mice received a femur osteotomy stabilized using an external fixator and were randomly assigned to five groups. Group 1 mice were scanned three times longitudinally during fracture healing using an optimized MRI scanning protocol to establish an algorithm to characterize the different fracture-callus tissues. Mice of groups 2–4 were scanned once on day 10, 14 or 21, respectively, euthanized after scanning and their femurs subjected to ex vivo μCT and histomorphometric analysis to compare the data assessed by MRI with μCT and histology. Control group 5 mice were not scanned. After 28 days, mice of groups 1 and 5 were euthanized and the fracture-healing outcome was evaluated by bending-test, μCT and histology to determine whether the repeated anesthesia, handling and the MRI measurements themselves influenced fracture healing. The callus-tissue values determined by MRI were mostly comparable to those obtained by μCT and histomorphometric analysis. However, at time points characterized by small relative bone or cartilage areas, MRI measurements were weakly comparable to histomorphometric data, possibly due to the inferior spatial resolution. Importantly, at the early and intermediate phases of healing, cartilage and fibrous-tissue values obtained by MRI were highly accurate. Furthermore, repeated anesthesia, handling and MRI scans did not impact bone healing. Therefore, we

  12. Measurement of tumor size in adult glioblastoma: Classical cross-sectional criteria on 2D MRI or volumetric criteria on high resolution 3D MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Mei-Yun, E-mail: meiyun9999@gmail.com [Department of Radiology, Henan Provincial People' s Hospital, 7 Weiwu Rd., Zhengzhou, Henan 450003 (China); Cheng, Jing-Liang, E-mail: cjr.chjl@vip.163.com [MRI Center, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052 (China); Han, Yan-Hong, E-mail: hyh_yafeng@yahoo.cn [Department of Radiology, Henan Provincial People' s Hospital, 7 Weiwu Rd., Zhengzhou, Henan 450003 (China); Li, Yong-Li, E-mail: shyliyongli@126.com [Department of Radiology, Henan Provincial People' s Hospital, 7 Weiwu Rd., Zhengzhou, Henan 450003 (China); Dai, Jian-Ping, E-mail: cjr.shidapeng@vip.163.com [Department of Radiology, Henan Provincial People' s Hospital, 7 Weiwu Rd., Zhengzhou, Henan 450003 (China); Shi, Da-Peng, E-mail: daijianping_2008@126.com [Department of Radiology, Henan Provincial People' s Hospital, 7 Weiwu Rd., Zhengzhou, Henan 450003 (China)

    2012-09-15

    Objective: To investigate the added value of volume on post-contrast three dimensional (3D) T1-weighted image (T1WI) over classical cross-sectional area on two dimensional (2D) T1WI in evaluating tumor response in glioblastoma multiforme (GBM). Methods: Tumor cross-sectional area and volume measurements were performed on 104 MRI studies from 42 adult patients with GBM on post-contrast 5 mm 2D T1WI and isotropic high resolution 3D T1WI, respectively. 52 pairs of MRI scans were analyzed for relative change. Radiographic responses were determined based on change in either area or volume. Results: A high correlation was revealed between tumor size measured by area on thick 2D and volume on high resolution 3D MRI in 104 scans (r = 0.82, p < 0.001). When four tumor response criteria were used according to the percentage changes (complete response/partial response/stable disease/progression), the kappa coefficient between the area on 2D and volume on 3D was 0.68 (p < 0.05) with an overall agreement of 81%. Conclusions: Tumor cross-sectional area on post-contrast 2D T1WI appears comparable to volume on 3D T1WI and should still be a practical alternate of volume on 3D for evaluating tumor response.

  13. Phonological ambiguity modulates resolution of semantic ambiguity during reading: An fMRI study of Hebrew.

    Science.gov (United States)

    Bitan, Tali; Kaftory, Asaf; Meiri-Leib, Adi; Eviatar, Zohar; Peleg, Orna

    2017-10-01

    The current fMRI study examined the role of phonology in the extraction of meaning from print in each hemisphere by comparing homophonic and heterophonic homographs (ambiguous words in which both meanings have the same or different sounds respectively, e.g., bank or tear). The analysis distinguished between the first phase, in which participants read ambiguous words without context, and the second phase in which the context resolves the ambiguity. Native Hebrew readers were scanned during semantic relatedness judgments on pairs of words in which the first word was either a homophone or a heterophone and the second word was related to its dominant or subordinate meaning. In Phase 1 there was greater activation for heterophones in left inferior frontal gyrus (IFG), pars opercularis, and more activation for homophones in bilateral IFG pars orbitalis, suggesting that resolution of the conflict at the phonological level has abolished the semantic ambiguity for heterophones. Reduced activation for all ambiguous words in temporo-parietal regions suggests that although ambiguity enhances controlled lexical selection processes in frontal regions it reduces reliance on bottom-up mapping processes. After presentation of the context, a larger difference between the dominant and subordinate meaning was found for heterophones in all reading-related regions, suggesting a greater engagement for heterophones with the dominant meaning. Altogether these results are consistent with the prominent role of phonological processing in visual word recognition. Finally, despite differences in hemispheric asymmetry between homophones and heterophones, ambiguity resolution, even toward the subordinate meaning, is largely left lateralized. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  14. Postoperative arachnoiditis diagnosed by high resolution fast spin-echo MRI of the lumbar spine

    Energy Technology Data Exchange (ETDEWEB)

    Fitt, G.J. [St. Mary`s Hospital, London (United Kingdom). Dept. of Radiology; Stevens, J.M. [St. Mary`s Hospital, London (United Kingdom). Dept. of Radiology]|[National Hospital for Neurology and Neurosurgery, London (United Kingdom)

    1995-02-01

    Chronic adhesive arachnoiditis is cited as an important cause of recurrent pain and disability after extradural lumbar disc surgery. Myelography using oil-based or ionic water-soluble contrast media was a major contributing factor, and it was not possible to distinguish the prevalence of arachnoiditis probably due to surgery alone. Today it should be possible to make this distinction, which was the purpose of this study. Using high-resolution MRI in 129 patients symptomatic at least 1 year after surgery, a prevalence of arachnoiditis of 20% was found, which dropped to 3% when patients who had undergone oil-based myelography were excluded. Arachnoiditis was diffuse in 88% and focal in 12%. When oil-based media were involved it was focal in 13%, and when not, in one of three cases. It was concluded that arachnoiditis does occur after extradural lumbar disc surgery independently of the use of some myelographic contrast media, and that it may be diffuse or confined only to the operated level. Its prevalence was estimated at 4.6%, four cases focal and two cases diffuse. The causes and clinical significance can only be the subject of speculation. (orig.)

  15. Is the type and extent of hippocampal sclerosis measurable on high-resolution MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Urbach, H; Schwarzwald, R [Medical Center University of Freiburg, Dept. of Neuroradiology, Freiburg (Germany); Huppertz, H.J. [Swiss Epilepsy Center, Zurich (Switzerland); Becker, A.J. [Medical Center University of Bonn, Department of Neuropathology, Bonn (Germany); Wagner, J. [Medical Center University of Bonn, Department of Epileptology, Bonn (Germany); Bahri, M. Delsous; Tschampa, H.J. [Medical Center University of Bonn, Department of Radiology/Neuroradiology, Bonn (Germany)

    2014-09-15

    The purpose of this study is to relate hippocampal volume and FLAIR signal intensity to Wyler grading of hippocampal sclerosis (HS). Of 100 consecutive patients with temporal lobe epilepsy and HS as histopathological diagnosis, 32 had high-resolution 3 Tesla MRI and anatomically well-preserved hippocampi following amygdalo-hippocampectomy. Hippocampal volume on 3D T1-weighted gradient echo and signal intensity on coronal FLAIR sequences were determined using FreeSurfer and SPM tools and related to Wyler grading. Seizure outcome was determined after 1 year. Histopathology showed four Wyler II, 19 Wyler III, and 9 Wyler IV HS. Hippocampal volumes were 3.08 ml for Wyler II (Wyler II/contralateral side: p > 0.05), 2.19 ml for Wyler III (p < 0.01), 2.62 ml for Wyler IV (p = 0.01), and 3.08 ml for the contralateral side. Normalized FLAIR signals were 1,354 (p = 0.0004), 1,408 (p < 0.0001), 1,371 (p < 0.04), and 1,296, respectively. Wyler II hippocampi were visually normal. Two of four (50 %) Wyler II, 16/19 (84 %) Wyler III, and 6/9 (66 %) Wyler IV patients achieved Engel I outcome. Combined volumetry and quantitative FLAIR signal analysis clearly identifies Wyler III and IV HS. Quantitative FLAIR signal analysis may be helpful to identify Wyler II HS. (orig.)

  16. High Resolution Three-Dimensional Delayed Contrast MRI Detects Endolymphatic Hydrops in Patients With Vertigo and Vestibular Schwannoma.

    Science.gov (United States)

    Moayer, Roxana; Ishiyama, Gail P; Karnezis, Stellios; Sepahdari, Ali R; Ishiyama, Akira

    2018-01-01

    Advances in high resolution magnetic resonance imaging (MRI) have enabled the detection of endolymphatic hydrops (EH), a pathological ballooning of the endolymphatic fluid system, known to be associated with Menière's disease. When a patient has a known diagnosis of vestibular schwannoma and develops recurrent episodic vertigo spells, many surgeons recommend surgical intervention, attributing the vestibular symptoms to the vestibular schwannoma. The aim of this study is to evaluate the clinical outcome in patients with vestibular schwannoma and EH, treated medically, for recurrent spells of vertigo. Two patients with EH and vestibular schwannoma who presented with recurrent spells of vertigo are included. Both had characteristic low frequency hearing loss ipsilateral to the schwannoma. MRI sequences with 3T scanner (Skyra, Siemens Healthcare, Erlangen, Germany) using high resolution three-dimensional delayed postcontrast protocol included "cisternographic" T2 and delayed intravenous-enhanced three-dimensional fluid-attenuation inversion recovery (DIVE-3D-FLAIR) sequences, performed with 2350 ms (bright perilymph) and 2050 ms (bright endolymph) inversion times and with subtracted images. MRI FLAIR evaluation of EH and presence or absence of vestibular symptoms. Both patients had resolution of the disabling vertigo spells with a diuretic, and Patient 1 had unchanged EH, while Patient 2 had partial resolution of the EH and the FLAIR hyperintensity. When EH coexists with vestibular schwannoma in a patient presenting with recurrent vertigo spells, medical treatments for EH may alleviate the vestibular symptoms. We recommend that patients with small vestibular schwannomas who present with vertigo spells undergo high resolution MRI to evaluate for EH and undergo a trial of medical treatment with diuretics.

  17. Local structure and global connectivity in the cerebral cortex: neuroinformatics, histology and ultra high resolution diffusion MRI in the rhesus and marmoset monkey brain

    OpenAIRE

    Reveley, Colin

    2017-01-01

    This thesis concerns the cortical connectivity in Primates. The efficacy of Diffusion weighted MRI (dMRI) is examined. White matter (“WM”) systems subjacent to cortex (“superficial WM” ) are found to be a limiting factor to dMRI tractography. Superficial WM systems are examined with dMRI itself, and with analysis of histological data from the scanned brains. dMRI data was acquired ex-vivo at exceptional spatial and angular resolution (250μm in Rhesus, 150μm in Marmoset). The superficial WM wa...

  18. High resolution pituitary gland MRI at 7.0 tesla: a clinical evaluation in Cushing's disease.

    Science.gov (United States)

    de Rotte, Alexandra A J; Groenewegen, Amy; Rutgers, Dik R; Witkamp, Theo; Zelissen, Pierre M J; Meijer, F J Anton; van Lindert, Erik J; Hermus, Ad; Luijten, Peter R; Hendrikse, Jeroen

    2016-01-01

    To evaluate the detection of pituitary lesions at 7.0 T compared to 1.5 T MRI in 16 patients with clinically and biochemically proven Cushing's disease. In seven patients, no lesion was detected on the initial 1.5 T MRI, and in nine patients it was uncertain whether there was a lesion. Firstly, two readers assessed both 1.5 T and 7.0 T MRI examinations unpaired in a random order for the presence of lesions. Consensus reading with a third neuroradiologist was used to define final lesions in all MRIs. Secondly, surgical outcome was evaluated. A comparison was made between the lesions visualized with MRI and the lesions found during surgery in 9/16 patients. The interobserver agreement for lesion detection was good at 1.5 T MRI (κ = 0.69) and 7.0 T MRI (κ = 0.62). In five patients, both the 1.5 T and 7.0 T MRI enabled visualization of a lesion on the correct side of the pituitary gland. In three patients, 7.0 T MRI detected a lesion on the correct side of the pituitary gland, while no lesion was visible at 1.5 T MRI. The interobserver agreement of image assessment for 7.0 T MRI in patients with Cushing's disease was good, and lesions were detected more accurately with 7.0 T MRI. Interobserver agreement for lesion detection on 1.5 T MRI was good; Interobserver agreement for lesion detection on 7.0 T MRI was good; 7.0 T enabled confirmation of unclear lesions at 1.5 T; 7.0 T enabled visualization of lesions not visible at 1.5 T.

  19. Spatial resolution and maximum compensation factor of two-dimensional selective excitation pulses for MRI of objects containing conductive implants

    Directory of Open Access Journals (Sweden)

    Taeseong Woo

    2017-05-01

    Full Text Available A quantitative diagnosis using magnetic resonance imaging (MRI can be disturbed by radiofrequency (RF field inhomogeneity induced by the conductive implants. This inhomogeneity causes a local decrease of the signal intensity around the conductor, resulting in a deterioration of the accurate quantification. In a previous study, we developed an MRI imaging method using a two-dimensional selective excitation pulse (2D pulse to mitigate signal inhomogeneity induced by metallic implants. In this paper, the effect of 2D pulse was evaluated quantitatively by numerical simulation and MRI experiments. We introduced two factors for evaluation, spatial resolution and maximum compensation factor. Numerical simulations were performed with two groups. One group was composed of four models with different signal loss width, to evaluate the spatial resolution of the 2D pulse. The other group is also composed of four models with different amounts of signal loss for evaluating maximum compensation factor. In MRI experiments, we prepared phantoms containing conductors, which have different electrical conductivities related with the amounts of signal intensity decrease. The recovery of signal intensity was observed by 2D pulses, in both numerical simulations and experiments.

  20. [Bony pathologies of the metacarpophalangeal joints in early rheumatoid arthritis: comparison of MRI and high-resolution SPECT].

    Science.gov (United States)

    Scherer, A; Wirrwar, A; Mattes-György, K; Blondin, D; Reichelt, D; Müller, H-W; Schneider, M; Mödder, U; Ostendorf, B

    2009-09-01

    Comparison of MRI with a newly developed high-resolution multi-pinhole single photon emission computed tomography (MPH-SPECT) regarding the detection of bony pathologies of the metacarpophalangeal (MCP) joints in patients with early rheumatoid arthritis (ERA). The clinically dominant hand of 15 patients with ERA (disease duration 6 months) was examined using MRI and MPH-SPECT. The evaluation of MRI was achieved according to RAMRIS criteria and for the MPH SPECT regarding pathological tracer uptake and distribution. Image fusions of MRI and MPH-SPECT were provided and the two methods were compared. In MRI 12 of 15 patients showed arthritic joint pathologies, while 8 patients exhibited soft tissue and bony changes. 4 patients had only soft tissue inflammation (synovitis) with a normal bone signal. In MPH-SPECT 10 of 15 patients showed pathologically increased bone metabolism. The fusion images presented a high agreement of the pathological changes in both methods, while areas with increased bone metabolism were not only present in the case of erosions, but also in the case of bone edema. In 2 patients increased bone metabolism was detectable in areas of MR tomographic normal bone, while a clear surrounding synovitis was present in each case here. The comparison of MPH-SPECT with MRI proves that the latter is a sensitive procedure for the detection of bony pathologies of MCP joints in ERA. A normal bone signal in MRI does not exclude early changes in bone metabolism in cases of severe synovialitis. Georg Thieme Verlag KG Stuttgart, New York.

  1. Accuracy of High-Resolution MRI with Lumen Distention in Rectal Cancer Staging and Circumferential Margin Involvement Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Iannicelli, Elsa; Di Renzo, Sara [Radiology Institute, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Ferri, Mario [Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Pilozzi, Emanuela [Department of Clinical and Molecular Sciences, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Di Girolamo, Marco; Sapori, Alessandra [Radiology Institute, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Ziparo, Vincenzo [Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); David, Vincenzo [Radiology Institute, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy); Department of Surgical and Medical Sciences and Translational Medicine, Faculty of Medicine and Psychology, University of Rome, Sapienza, Sant' Andrea Hospital, Rome 00189 (Italy)

    2014-07-01

    To evaluate the accuracy of magnetic resonance imaging (MRI) with lumen distention for rectal cancer staging and circumferential resection margin (CRM) involvement prediction. Seventy-three patients with primary rectal cancer underwent high-resolution MRI with a phased-array coil performed using 60-80 mL room air rectal distention, 1-3 weeks before surgery. MRI results were compared to postoperative histopathological findings. The overall MRI T staging accuracy was calculated. CRM involvement prediction and the N staging, the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were assessed for each T stage. The agreement between MRI and histological results was assessed using weighted-kappa statistics. The overall MRI accuracy for T staging was 93.6% (k = 0.85). The accuracy, sensitivity, specificity, PPV and NPV for each T stage were as follows: 91.8%, 86.2%, 95.5%, 92.6% and 91.3% for the group ≤ T2; 90.4%, 94.6%, 86.1%, 87.5% and 94% for T3; 98,6%, 85.7%, 100%, 100% and 98.5% for T4, respectively. The predictive CRM accuracy was 94.5% (k = 0.86); the sensitivity, specificity, PPV and NPV were 89.5%, 96.3%, 89.5%, and 96.3% respectively. The N staging accuracy was 68.49% (k = 0.4). MRI performed with rectal lumen distention has proved to be an effective technique both for rectal cancer staging and involved CRM predicting.

  2. Improving the Specificity of High Resolution Breast MRI by Optimizing Data Acquisition Techniques and Diagnostic

    National Research Council Canada - National Science Library

    Partridge, Savannah

    1999-01-01

    .... Contrast-enhanced breast MRI has shown greater sensitivity than mammography in the detection of small breast lesions, and can also successfully image dense, augmented, and postoperative breasts...

  3. High resolution pituitary gland MRI at 7.0 tesla: a clinical evaluation in Cushing's disease

    NARCIS (Netherlands)

    Rotte, A.A. de; Groenewegen, A.; Rutgers, D.R.; Witkamp, T.; Zelissen, P.M.; Meijer, F.J.A.; Lindert, E.J. van; Hermus, A.R.M.M.; Luijten, P.R.; Hendrikse, J.

    2016-01-01

    OBJECTIVE: To evaluate the detection of pituitary lesions at 7.0 T compared to 1.5 T MRI in 16 patients with clinically and biochemically proven Cushing's disease. METHODS: In seven patients, no lesion was detected on the initial 1.5 T MRI, and in nine patients it was uncertain whether there was a

  4. Fast bilateral breast coverage with high spectral and spatial resolution (HiSS) MRI at 3T.

    Science.gov (United States)

    Medved, Milica; Li, Hui; Abe, Hiroyuki; Sheth, Deepa; Newstead, Gillian M; Olopade, Olufunmilayo I; Giger, Maryellen L; Karczmar, Gregory S

    2017-11-01

    To develop and assess a full-coverage, sensitivity encoding (SENSE)-accelerated breast high spatial and spectral resolution (HiSS) magnetic resonance imaging (MRI) within clinically reasonable times as a potential nonenhanced MRI protocol for breast density measurement or breast cancer screening. Sixteen women with biopsy-proven cancer or suspicious lesions, and 13 women who were healthy volunteers or were screened for breast cancer, received 3T breast MRI exams, including SENSE-accelerated HiSS MRI, which was implemented as a submillimeter spatial resolution echo-planar spectroscopic imaging (EPSI) sequence. In postprocessing, fat and water resonance peak height and integral images were generated from EPSI data. The postprocessing software was custom-designed, and new algorithms were developed to enable processing of whole-coverage axial HiSS datasets. Water peak height HiSS images were compared to pre- and postcontrast T 1 -weighted images. Fat suppression was quantified as parenchymal-to-suppressed-fat signal ratio in HiSS water peak height and nonenhanced T 1 -weighted images, and artifact levels were scored. Approximately a 4-fold decrease in acquisition speed, with a concurrent 2.5-fold decrease in voxel size, was achieved, with low artifact levels, and with spectral signal-to-noise ratio (SNR) of 45:1. Fat suppression was 1.9 times more effective (P SENSE-accelerated breast HiSS MRI within clinically reasonable times, as a potential protocol for breast density measurement or breast cancer screening. 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1341-1348. © 2017 International Society for Magnetic Resonance in Medicine.

  5. High resolution MRI for preoperative work-up of neonates with an anorectal malformation: a direct comparison with distal pressure colostography/fistulography

    NARCIS (Netherlands)

    Thomeer, M.G.; Devos, A.; Lequin, M.; Graaf, N. De; Meeussen, C.J.; Meradji, M.; Blaauw, I. de; Sloots, C.E.

    2015-01-01

    OBJECTIVE: To compare MRI and colostography/fistulography in neonates with anorectal malformations (ARM), using surgery as reference standard. METHODS: Thirty-three neonates (22 boys) with ARM were included. All patients underwent both preoperative high-resolution MRI (without sedation or contrast

  6. High resolution MRI for preoperative work-up of neonates with an anorectal malformation: a direct comparison with distal pressure colostography/fistulography

    NARCIS (Netherlands)

    M. Thomeer (Maarten); A.S. Devos (Annick); M. Leguin (Maarten); N. De Graaf (Nanko); C.J.H.M. Meeussen (Conny ); M. Meradji (Morteza); I. de Blaauw (Ivo); C.E.J. Sloots (Pim)

    2015-01-01

    textabstractObjective: To compare MRI and colostography/fistulography in neonates with anorectal malformations (ARM), using surgery as reference standard. Methods: Thirty-three neonates (22 boys) with ARM were included. All patients underwent both preoperative high-resolution MRI (without sedation

  7. MR-compatibility of a high-resolution small animal PET insert operating inside a 7 T MRI

    Science.gov (United States)

    Thiessen, J. D.; Shams, E.; Stortz, G.; Schellenberg, G.; Bishop, D.; Khan, M. S.; Kozlowski, P.; Retière, F.; Sossi, V.; Thompson, C. J.; Goertzen, A. L.

    2016-11-01

    A full-ring PET insert consisting of 16 PET detector modules was designed and constructed to fit within the 114 mm diameter gradient bore of a Bruker 7 T MRI. The individual detector modules contain two silicon photomultiplier (SiPM) arrays, dual-layer offset LYSO crystal arrays, and high-definition multimedia interface (HDMI) cables for both signal and power transmission. Several different RF shielding configurations were assessed prior to construction of a fully assembled PET insert using a combination of carbon fibre and copper foil for RF shielding. MR-compatibility measurements included field mapping of the static magnetic field (B 0) and the time-varying excitation field (B 1) as well as acquisitions with multiple pulse sequences: spin echo (SE), rapid imaging with refocused echoes (RARE), fast low angle shot (FLASH) gradient echo, and echo planar imaging (EPI). B 0 field maps revealed a small degradation in the mean homogeneity (+0.1 ppm) when the PET insert was installed and operating. No significant change was observed in the B 1 field maps or the image homogeneity of various MR images, with a 9% decrease in the signal-to-noise ratio (SNR) observed only in EPI images acquired with the PET insert installed and operating. PET detector flood histograms, photopeak amplitudes, and energy resolutions were unchanged in individual PET detector modules when acquired during MRI operation. There was a small baseline shift on the PET detector signals due to the switching amplifiers used to power MRI gradient pulses. This baseline shift was observable when measured with an oscilloscope and varied as a function of the gradient duty cycle, but had no noticeable effect on the performance of the PET detector modules. Compact front-end electronics and effective RF shielding led to minimal cross-interference between the PET and MRI systems. Both PET detector and MRI performance was excellent, whether operating as a standalone system or a hybrid PET/MRI.

  8. High resolution 3D MRI of mouse mammary glands with intra-ductal injection of contrast media.

    Science.gov (United States)

    Markiewicz, Erica; Fan, Xiaobing; Mustafi, Devkumar; Zamora, Marta; Roman, Brian B; Jansen, Sanaz A; Macleod, Kay; Conzen, Suzanne D; Karczmar, Gregory S

    2015-01-01

    The purpose of this study was to use high resolution three-dimensional (3D) magnetic resonance imaging (MRI) to study mouse mammary gland ductal architecture based on intra-ductal injection of contrast agents. Female FVB/N mice age 12-20 weeks (n=12), were used in this study. A 34G, 45° tip Hamilton needle with a 25μL Hamilton syringe was inserted into the tip of the nipple. Approximately 20-25μL of a Gadodiamide/Trypan blue/saline solution was injected slowly over one minute into the nipple and duct. To prevent washout of contrast media from ducts due to perfusion, and maximize the conspicuity of ducts on MRI, mice were sacrificed one minute after injection. High resolution 3D T1-weighted images were acquired on a 9.4T Bruker scanner after sacrifice to eliminate motion artifacts and reduce contrast media leakage from ducts. Trypan blue staining was well distributed throughout the ductal tree. MRI showed the mammary gland ductal structure clearly. In spoiled gradient echo T1-weighted images, the signal-to-noise ratio of regions identified as enhancing mammary ducts following contrast injection was significantly higher than that of muscle (pcontrast media (pcontrast agents to measure metabolism or target receptors in normal ducts and ducts with in situ cancers. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Angiogenesis and Invasiveness in Prostate Cancer Detected With Spectral and Spatial Resolution MRI

    National Research Council Canada - National Science Library

    Karczmar, Gregory

    2003-01-01

    .... Related work from this laboratory is presented in a number of other publications 2-9. Work from other laboratories shows that closely related methods also provide advantages for anatomic 10 and functional 11-14 MRI...

  10. Forearm Muscle Volumes Can Be Accurately Quantified From High Resolution Magnetic Resonance Imaging (MRI)

    OpenAIRE

    Eng, Carolyn M.; Abrams, Geoff D.; Smallwood, Laura R.; Lieber, Richard L.; Ward, Samuel R.

    2007-01-01

    Upper extremity musculoskeletal modeling is becoming increasingly sophisticated, creating a growing need for subject-specific muscle size parameters. One method for determining subject-specific muscle volume is magnetic resonance imaging (MRI). The purpose of this study was to determine the validity of MRI-derived muscle volumes in the human forearm across a variety of muscle sizes and shapes. Seventeen cadaveric forearms were scanned using a fast spoiled gradient echo pulse sequence with hig...

  11. A subject-specific framework for in vivo myeloarchitectonic analysis using high resolution quantitative MRI.

    Science.gov (United States)

    Waehnert, Miriam D; Dinse, Juliane; Schäfer, Andreas; Geyer, Stefan; Bazin, Pierre-Louis; Turner, Robert; Tardif, Christine Lucas

    2016-01-15

    Structural magnetic resonance imaging can now resolve laminar features within the cerebral cortex in vivo. A variety of intracortical contrasts have been used to study the cortical myeloarchitecture with the purpose of mapping cortical areas in individual subjects. In this article, we first briefly review recent advances in MRI analysis of cortical microstructure to portray the potential and limitations of the current state-of-the-art. We then present an integrated framework for the analysis of intracortical structure, composed of novel image processing tools designed for high resolution cortical images. The main features of our framework are the segmentation of quantitative T1 maps to delineate the cortical boundaries (Bazin et al., 2014), and the use of an equivolume layering model to define an intracortical coordinate system that follows the anatomical layers of the cortex (Waehnert et al., 2014). We evaluate the framework with 150μm isotropic post mortem T2(∗)-weighted images and 0.5mm isotropic in vivo T1 maps, a quantitative index of myelin content. We study the laminar structure of the primary visual cortex (Brodmann area 17) in the post mortem and in vivo data, as well as the central sulcus region in vivo, in particular Brodmann areas 1, 3b and 4. We also investigate the impact of the layering models on the relationship between T1 and cortical curvature. Our experiments demonstrate that the equivolume intracortical surfaces and transcortical profiles best reflect the laminar structure of the cortex in areas of curvature in comparison to the state-of-the-art equidistant and Laplace implementations. This framework generates a subject specific intracortical coordinate system, the basis for subsequent architectonic analyses of the cortex. Any structural or functional contrast co-registered to the T1 maps, used to segment the cortex, can be sampled on the curved grid for analysis. This work represents an important step towards in vivo structural brain mapping

  12. T1-weighted in vivo human whole brain MRI dataset with an ultrahigh isotropic resolution of 250 μm

    Science.gov (United States)

    Lüsebrink, Falk; Sciarra, Alessandro; Mattern, Hendrik; Yakupov, Renat; Speck, Oliver

    2017-03-01

    We present an ultrahigh resolution in vivo human brain magnetic resonance imaging (MRI) dataset. It consists of T1-weighted whole brain anatomical data acquired at 7 Tesla with a nominal isotropic resolution of 250 μm of a single young healthy Caucasian subject and was recorded using prospective motion correction. The raw data amounts to approximately 1.2 TB and was acquired in eight hours total scan time. The resolution of this dataset is far beyond any previously published in vivo structural whole brain dataset. Its potential use is to build an in vivo MR brain atlas. Methods for image reconstruction and image restoration can be improved as the raw data is made available. Pre-processing and segmentation procedures can possibly be enhanced for high magnetic field strength and ultrahigh resolution data. Furthermore, potential resolution induced changes in quantitative data analysis can be assessed, e.g., cortical thickness or volumetric measures, as high quality images with an isotropic resolution of 1 and 0.5 mm of the same subject are included in the repository as well.

  13. NON-CONTRAST MAGNETIC RESONANCE UROGRAPHY

    OpenAIRE

    Arpita C; Nava Kishore K; Ananda Reddy C; Dushyanth M

    2016-01-01

    BACKGROUND AND PURPOSE Magnetic Resonance (MR) urography with its optimal contrast resolution and lack of ionizing radiation provides a comprehensive examination of the entire urinary tract noninvasively. MR urography is clinically useful in the evaluation of suspected urinary tract obstruction, haematuria, congenital anomalies, and surgically altered anatomy. It is particularly useful in cases of where there is contraindication of ionizing radiation and in paediatric and pregn...

  14. Dua-energy virtual noncontrast imaging in diagnosis of cervical metastasis lymph nodes

    Directory of Open Access Journals (Sweden)

    Fei Fu

    2015-01-01

    Full Text Available Objective: The aim of this study was to evaluate the clinical value of dua-energy virtual noncontrast imaging (DVNCT in the diagnosis of cervical metastasis lymph nodes. Materials and Methods: From February 2014 to January 2015, 41 patients with 98 enlarged cervical lymph nodes were recruited in this study. All the enlarged lymph nodes were pathology confirmed. The patients received DVNCT and conventional noncontrast scan. The difference of average computed tomography (CT value, signal to noise ratio, a contrast to noise ratio, image subjective assessment, and lesion detectability between virtual noncontrast imaging and conventional noncontrast scan were compared. The radiation dose of virtual noncontrast imaging and real noncontrast imaging of cervical lymph node were also compared. The diagnostic sensitivity and specificity for DVNCT was also evaluated. Results: No statistical difference of average CT value, signal to noise ratio, a contrast to noise ratio, image subjective assessment, and radiation dosage between virtual noncontrast imaging and conventional noncontrast scan were found. However, the radiation dosage of DVNCT was significant lower than that of conventional noncontrast scan (P < 0.05. The diagnostic sensitivity and specificity for malignant metastasis lymph node were 88.6% and 70.3% by DVNCT. Conclusion: DVNCT combined with contrast imaging can provide clear images in the diagnosis of enlarged cervical lymph nodes and reduce radiation dosage.

  15. Parametric analysis of the spatial resolution and signal-to-noise ratio in super-resolved spatiotemporally encoded (SPEN) MRI.

    Science.gov (United States)

    Ben-Eliezer, Noam; Shrot, Yoav; Frydman, Lucio; Sodickson, Daniel K

    2014-08-01

    Spatiotemporally Encoded (SPEN) MRI is based on progressive point-by-point refocusing of the image in the spatial rather than the k-space domain through the use of frequency-swept radiofrequency pulses and quadratic phase profiles. This technique provides high robustness against frequency-offsets including B0 inhomogeneities and chemical-shift (e.g., fat/water) distortions, and can consequently perform fMRI at challenging regions such as the orbitofrontal cortex and the olfactory bulb, as well as to improve imaging near metallic implants. This work aims to establish a comprehensive framework for the implementation and super-resolved reconstruction of SPEN-based imaging, and to accurately quantify this method's spatial-resolution and signal-to-noise ratio (SNR). A stepwise formalism was laid-out for calculating the optimal experimental parameters for SPEN, followed by analytical analysis of the ensuing SNR and spatial-resolution versus conventional k-space encoding. Predictions were then confirmed using computer simulations and experimentally. Our findings show that SPEN is governed by the same fundamental signal-processing principles as k-space encoding, leading to similar averaging properties, and ultimately similar spatial-resolution and SNR levels as k-space encoding. Presented analysis is applicable to general multidimensional SPEN designs and provides a unified framework for the analysis of future SPEN and similar approaches based on quadratic phase encoding. Copyright © 2013 Wiley Periodicals, Inc.

  16. Interactive local super-resolution reconstruction of whole-body MRI mouse data: a pilot study with applications to bone and kidney metastases.

    Directory of Open Access Journals (Sweden)

    Oleh Dzyubachyk

    Full Text Available In small animal imaging studies, when the locations of the micro-structures of interest are unknown a priori, there is a simultaneous need for full-body coverage and high resolution. In MRI, additional requirements to image contrast and acquisition time will often make it impossible to acquire such images directly. Recently, a resolution enhancing post-processing technique called super-resolution reconstruction (SRR has been demonstrated to improve visualization and localization of micro-structures in small animal MRI by combining multiple low-resolution acquisitions. However, when the field-of-view is large relative to the desired voxel size, solving the SRR problem becomes very expensive, in terms of both memory requirements and computation time. In this paper we introduce a novel local approach to SRR that aims to overcome the computational problems and allow researchers to efficiently explore both global and local characteristics in whole-body small animal MRI. The method integrates state-of-the-art image processing techniques from the areas of articulated atlas-based segmentation, planar reformation, and SRR. A proof-of-concept is provided with two case studies involving CT, BLI, and MRI data of bone and kidney tumors in a mouse model. We show that local SRR-MRI is a computationally efficient complementary imaging modality for the precise characterization of tumor metastases, and that the method provides a feasible high-resolution alternative to conventional MRI.

  17. Automatic coronary calcium scoring using noncontrast and contrast CT images

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Guanyu, E-mail: yang.list@seu.edu.cn; Chen, Yang; Shu, Huazhong [Laboratory of Image Science and Technology, School of Computer Science and Engineering, Southeast University, No. 2, Si Pai Lou, Nanjing 210096 (China); Centre de Recherche en Information Biomédicale Sino-Français (LIA CRIBs), Nanjing 210096 (China); Key Laboratory of Computer Network and Information Integration, Southeast University, Ministry of Education, Nanjing 210096 (China); Ning, Xiufang; Sun, Qiaoyu [Laboratory of Image Science and Technology, School of Computer Science and Engineering, Southeast University, No. 2, Si Pai Lou, Nanjing 210096 (China); Key Laboratory of Computer Network and Information Integration, Southeast University, Ministry of Education, Nanjing 210096 (China); Coatrieux, Jean-Louis [INSERM-U1099, Rennes F-35000 (France); Labotatoire Traitement du Signal et de l’Image (LTSI), Université de Rennes 1, Campus de Beaulieu, Bat. 22, Rennes 35042 Cedex (France); Centre de Recherche en Information Biomédicale Sino-Français (LIA CRIBs), Nanjing 210096 (China)

    2016-05-15

    Purpose: Calcium scoring is widely used to assess the risk of coronary heart disease (CHD). Accurate coronary artery calcification detection in noncontrast CT image is a prerequisite step for coronary calcium scoring. Currently, calcified lesions in the coronary arteries are manually identified by radiologists in clinical practice. Thus, in this paper, a fully automatic calcium scoring method was developed to alleviate the work load of the radiologists or cardiologists. Methods: The challenge of automatic coronary calcification detection is to discriminate the calcification in the coronary arteries from the calcification in the other tissues. Since the anatomy of coronary arteries is difficult to be observed in the noncontrast CT images, the contrast CT image of the same patient is used to extract the regions of the aorta, heart, and coronary arteries. Then, a patient-specific region-of-interest (ROI) is generated in the noncontrast CT image according to the segmentation results in the contrast CT image. This patient-specific ROI focuses on the regions in the neighborhood of coronary arteries for calcification detection, which can eliminate the calcifications in the surrounding tissues. A support vector machine classifier is applied finally to refine the results by removing possible image noise. Furthermore, the calcified lesions in the noncontrast images belonging to the different main coronary arteries are identified automatically using the labeling results of the extracted coronary arteries. Results: Forty datasets from four different CT machine vendors were used to evaluate their algorithm, which were provided by the MICCAI 2014 Coronary Calcium Scoring (orCaScore) Challenge. The sensitivity and positive predictive value for the volume of detected calcifications are 0.989 and 0.948. Only one patient out of 40 patients had been assigned to the wrong risk category defined according to Agatston scores (0, 1–100, 101–300, >300) by comparing with the ground

  18. The resolution sensitivity of the Asian summer monsoon and its inter-model comparison between MRI-AGCM and MetUM

    Science.gov (United States)

    Ogata, Tomomichi; Johnson, Stephanie J.; Schiemann, Reinhard; Demory, Marie-Estelle; Mizuta, Ryo; Yoshida, Kohei; Osamu Arakawa

    2017-11-01

    In this study, we compare the resolution sensitivity of the Asian Summer Monsoon (ASM) in two Atmospheric General Circulation Models (AGCMs): the MRI-AGCM and the MetUM. We analyze the MetUM at three different resolutions, N96 (approximately 200-km mesh on the equator), N216 (90-km mesh) and N512 (40-km mesh), and the MRI-AGCM at TL95 (approximately 180-km mesh on the equator), TL319 (60-km mesh), and TL959 (20-km mesh). The MRI-AGCM and the MetUM both show decreasing precipitation over the western Pacific with increasing resolution, but their precipitation responses differ over the Indian Ocean. In MRI-AGCM, a large precipitation increase appears off the equator (5-20°N). In MetUM, this off-equatorial precipitation increase is less significant and precipitation decreases over the equator. Moisture budget analysis demonstrates that a changing in moisture flux convergence at higher resolution is related to the precipitation response. Orographic effects, intra-seasonal variability and the representation of the meridional thermal gradient are explored as possible causes of the resolution sensitivity. Both high-resolution AGCMs (TL959 and N512) can represent steep topography, which anchors the rainfall pattern over south Asia and the Maritime Continent. In MRI-AGCM, representation of low pressure systems in TL959 also contributes to the rainfall pattern. Furthermore, the seasonal evolution of the meridional thermal gradient appears to be more accurate at higher resolution, particularly in the MRI-AGCM. These findings emphasize that the impact of resolution is only robust across the two AGCMs for some features of the ASM, and highlights the importance of multi-model studies of GCM resolution sensitivity.

  19. Development of a high-resolution detection module for the INSERT SPECT/MRI system

    Energy Technology Data Exchange (ETDEWEB)

    Busca, Paolo; Fiorini, Carlo; Butt, Arslan D; Occhipinti, Michele; Quaglia, Riccardo; Trigilio, Paolo [Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Via Golgi 40, 20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via Celoria 16, 20133 Milano (Italy); Nemeth, Gabor; Major, Peter; Bukki, Tamas; Nagy, Kalman [Mediso Medical Imaging Systems, Alsotorokvesz 14, H-1022 Budapest (Hungary); Piemonte, Claudio; Ferri, Alessandro; Gola, Alberto [Fondazione Bruno Kessler (FBK), Via Sommarive, 18, 38123 Trento (Italy); Rieger, Jan [MRI.TOOLS GmbH, Robert-Roessle-Str. 10, 13125 Berlin (Germany); Niendorf, Thoralf [MRI.TOOLS GmbH, Robert-Roessle-Str. 10, 13125 Berlin (Germany); Berlin Ultrahigh Field Facility (B.UniversityF.F.), Max-Delbrueck-Center for Molecular Medicine, Berlin (Germany)

    2014-07-29

    A new multi-modality imaging tool is under development in the framework of the INSERT (Integrated SPECT/MRI for Enhanced Stratification in Radio-chemo Therapy) project, supported by the European Community. The final goal is to develop a custom SPECT apparatus that can be used as an insert for commercially available MRI systems. INSERT is expected to offer more effective and earlier diagnosis with potentially better outcome in survival for the treatment of brain tumors, primarily glioma. Two SPECT prototypes are being developed, one dedicated to preclinical imaging (7 and 9.4 T), the second one dedicated to clinical imaging (3 T).

  20. High-resolution MRI assessment of dactylitis in psoriatic arthritis shows flexor tendon pulley and sheath-related enthesitis.

    Science.gov (United States)

    Tan, Ai Lyn; Fukuba, Eiji; Halliday, Nicola Ann; Tanner, Steven F; Emery, Paul; McGonagle, Dennis

    2015-01-01

    Dactylitis is a hallmark of psoriatic arthritis (PsA) where flexor tenosynovitis is common. This study explored the microanatomical basis of dactylitis using high-resolution MRI (hrMRI) to visualise the small entheses around the digits. Twelve patients with psoriatic dactylitis (4 fingers, 8 toes), and 10 healthy volunteers (6 fingers, 4 toes) had hrMRI of the digits using a 'microscopy' coil and contrast enhancement. All structures were evaluated including the tendons and ligaments, related enthesis organs, pulleys, volar/plantar plates and tendon sheaths. In dactylitis, collateral ligament enthesitis was seen in nine digits (75%), extensor tendon enthesitis in six digits (50%), functional enthesitis (5 digits, 42%), abnormal enhancement at the volar plates (2/5 joints, 40%) and the plantar plate (1/5 joints, 20%). Nine cases (75%) demonstrated flexor tenosynovitis, with flexor tendon pulley/flexor sheath microenthesopathy observed in 50% of all cases. Less abnormalities which were milder was observed in the normal controls, none of whom had any signal changes in the tendon pulleys or fibrous sheaths. This study provides proof of concept for a link between dactylitis and 'digital polyenthesitis' including disease of the miniature enthesis pulleys of the flexor tendons, further affirming the concept of enthesitis in PsA. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  1. Retrospective Reconstruction of High Temporal Resolution Cine Images from Real-Time MRI using Iterative Motion Correction

    DEFF Research Database (Denmark)

    Hansen, Michael Schacht; Sørensen, Thomas Sangild; Arai, Andrew

    2012-01-01

    Cardiac function has traditionally been evaluated using breath-hold cine acquisitions. However, there is a great need for free breathing techniques in patients who have difficulty in holding their breath. Real-time cardiac MRI is a valuable alternative to the traditional breath-hold imaging...... approach, but the real-time images are often inferior in spatial and temporal resolution. This article presents a general method for reconstruction of high spatial and temporal resolution cine images from a real-time acquisition acquired over multiple cardiac cycles. The method combines parallel imaging...... and motion correction based on nonrigid registration and can be applied to arbitrary k-space trajectories. The method is demonstrated with real-time Cartesian imaging and Golden Angle radial acquisitions, and the motion-corrected acquisitions are compared with raw real-time images and breath-hold cine...

  2. 3D-MB-MUSE: A robust 3D multi-slab, multi-band and multi-shot reconstruction approach for ultrahigh resolution diffusion MRI.

    Science.gov (United States)

    Bruce, Iain P; Chang, Hing-Chiu; Petty, Christopher; Chen, Nan-Kuei; Song, Allen W

    2017-10-01

    Recent advances in achieving ultrahigh spatial resolution (e.g. sub-millimeter) diffusion MRI (dMRI) data have proven highly beneficial in characterizing tissue microstructures in organs such as the brain. However, the routine acquisition of in-vivo dMRI data at such high spatial resolutions has been largely prohibited by factors that include prolonged acquisition times, motion induced artifacts, and low SNR. To overcome these limitations, we present here a framework for acquiring and reconstructing 3D multi-slab, multi-band and interleaved multi-shot EPI data, termed 3D-MB-MUSE. Through multi-band excitations, the simultaneous acquisition of multiple 3D slabs enables whole brain dMRI volumes to be acquired in-vivo on a 3 T clinical MRI scanner at high spatial resolution within a reasonably short amount of time. Representing a true 3D model, 3D-MB-MUSE reconstructs an entire 3D multi-band, multi-shot dMRI slab at once while simultaneously accounting for coil sensitivity variations across the slab as well as motion induced artifacts commonly associated with both 3D and multi-shot diffusion imaging. Such a reconstruction fully preserves the SNR advantages of both 3D and multi-shot acquisitions in high resolution dMRI images by removing both motion and aliasing artifacts across multiple dimensions. By enabling ultrahigh resolution dMRI for routine use, the 3D-MB-MUSE framework presented here may prove highly valuable in both clinical and research applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Correlation of Scar in Cardiac MRI and High‐Resolution Contact Mapping of Left Ventricle in a Chronic Infarct Model

    Science.gov (United States)

    THAJUDEEN, ANEES; STEWART, BRIAN; COKIC, IVAN; NAKAGAWA, HIROSHI; SHEHATA, MICHAEL; AMORN, ALLEN M.; KALI, AVINASH; LIU, EZH; HARLEV, DORON; BENNETT, NATHAN; DHARMAKUMAR, ROHAN; CHUGH, SUMEET S.; WANG, XUNZHANG

    2015-01-01

    Background Endocardial mapping for scars and abnormal electrograms forms the most essential component of ventricular tachycardia ablation. The utility of ultra‐high resolution mapping of ventricular scar was assessed using a multielectrode contact mapping system in a chronic canine infarct model. Methods Chronic infarcts were created in five anesthetized dogs by ligating the left anterior descending coronary artery. Late gadolinium‐enhanced magnetic resonance imaging (LGE MRI) was obtained 4.9 ± 0.9 months after infarction, with three‐dimensional (3D) gadolinium enhancement signal intensity maps at 1‐mm and 5‐mm depths from the endocardium. Ultra‐high resolution electroanatomical maps were created using a novel mapping system (Rhythmia Mapping System, Rhythmia Medical/Boston Scientific, Marlborough, MA, USA) Rhythmia Medical, Boston Scientific, Marlborough, MA, USA with an 8.5F catheter with mini‐basket electrode array (64 tiny electrodes, 2.5‐mm spacing, center‐to‐center). Results The maps contained 7,754 ± 1,960 electrograms per animal with a mean resolution of 2.8 ± 0.6 mm. Low bipolar voltage (transmural scar, and dense transmural scar) as well as normal tissue, were significantly different. A unipolar voltage of transmural extension of scar in MRI. Electrograms exhibiting isolated late potentials (ILPs) were manually annotated and ILP maps were created showing ILP location and timing. ILPs were identified in 203 ± 159 electrograms per dog (within low‐voltage areas) and ILP maps showed gradation in timing of ILPs at different locations in the scar. Conclusions Ultra‐high resolution contact electroanatomical mapping accurately localizes ventricular scar and abnormal myocardial tissue in this chronic canine infarct model. The high fidelity electrograms provided clear identification of the very low amplitude ILPs within the scar tissue and has the potential to quickly identify targets for ablation. PMID:25656924

  4. Correlation of scar in cardiac MRI and high-resolution contact mapping of left ventricle in a chronic infarct model.

    Science.gov (United States)

    Thajudeen, Anees; Jackman, Warren M; Stewart, Brian; Cokic, Ivan; Nakagawa, Hiroshi; Shehata, Michael; Amorn, Allen M; Kali, Avinash; Liu, Ezh; Harlev, Doron; Bennett, Nathan; Dharmakumar, Rohan; Chugh, Sumeet S; Wang, Xunzhang

    2015-06-01

    Endocardial mapping for scars and abnormal electrograms forms the most essential component of ventricular tachycardia ablation. The utility of ultra-high resolution mapping of ventricular scar was assessed using a multielectrode contact mapping system in a chronic canine infarct model. Chronic infarcts were created in five anesthetized dogs by ligating the left anterior descending coronary artery. Late gadolinium-enhanced magnetic resonance imaging (LGE MRI) was obtained 4.9 ± 0.9 months after infarction, with three-dimensional (3D) gadolinium enhancement signal intensity maps at 1-mm and 5-mm depths from the endocardium. Ultra-high resolution electroanatomical maps were created using a novel mapping system (Rhythmia Mapping System, Rhythmia Medical/Boston Scientific, Marlborough, MA, USA) Rhythmia Medical, Boston Scientific, Marlborough, MA, USA with an 8.5F catheter with mini-basket electrode array (64 tiny electrodes, 2.5-mm spacing, center-to-center). The maps contained 7,754 ± 1,960 electrograms per animal with a mean resolution of 2.8 ± 0.6 mm. Low bipolar voltage (transmural scar, and dense transmural scar) as well as normal tissue, were significantly different. A unipolar voltage of transmural extension of scar in MRI. Electrograms exhibiting isolated late potentials (ILPs) were manually annotated and ILP maps were created showing ILP location and timing. ILPs were identified in 203 ± 159 electrograms per dog (within low-voltage areas) and ILP maps showed gradation in timing of ILPs at different locations in the scar. Ultra-high resolution contact electroanatomical mapping accurately localizes ventricular scar and abnormal myocardial tissue in this chronic canine infarct model. The high fidelity electrograms provided clear identification of the very low amplitude ILPs within the scar tissue and has the potential to quickly identify targets for ablation. ©2015 The Authors. Pacing and Clinical Electrophysiology Published by Wiley Periodicals, Inc.

  5. High Resolution MRI Reveals Detailed Layer Structures in Early Human Fetal Stages: In Vitro Study with Histologic Correlation.

    Science.gov (United States)

    Wang, Rongpin; Dai, Guangping; Takahashi, Emi

    2015-01-01

    An understanding of normal fetal brain development is essential in detecting the early onset of brain disorders. It is challenging to obtain high-quality images that show detailed local anatomy in the early fetal stages because the fetal brain is very small with rapidly-changing complex structures related to brain development, including neurogenesis, neuronal migration, and axonal elongation. Previous magnetic resonance imaging (MRI) studies detected three layers throughout the fetal cerebral wall that showed differences in MR contrasts at 10 gestational weeks (GW), which is one of the earliest ages studied using MRI. Contrary to the MRI studies, histological studies found more layers at this fetal age. The purpose of this work is to study the development of brain structures from an early fetal period to an early second trimester stage using ex vivo MRI and compare it to histology. Special attention was paid to laminar structures in the cerebral wall. T2-weighted imaging was performed on fetal brain specimens ranging from 10 GW to 18 GW on a 4.7 tesla MR scanner. We obtained standard grayscale as well as color-coded images using weighted red-green-blue scales, and compared them with the histological images. Our study confirmed laminar structure in the cerebral wall in all the fetal specimens studied. We found that MRI detected four layers within the cerebral wall as early as 10 GW during the early fetal period (10-13 GW). Early second trimester (15-18 GW) was characterized by the emergence of subplate structures and five layers within the cerebral wall. The color-coded images were more useful than the standard grayscale images in detecting the laminar structures. Scans with appropriate parameters from a high tesla MR scanner showed detailed laminar structures even through a very small and thin cerebral wall at 10 GW ex vivo. A combination of high-resolution structural imaging and color-coding processing with histological analysis may be a potential tool for

  6. High resolution MRI reveals detailed layer structures in early human fetal stages: In vitro study with histologic correlation

    Directory of Open Access Journals (Sweden)

    Rongpin eWang

    2015-11-01

    Full Text Available An understanding of normal fetal brain development is essential in detecting the early onset of brain disorders. It is challenging to obtain high-quality images that show detailed local anatomy in the early fetal stages because the fetal brain is very small with rapidly-changing complex structures related to brain development, including neurogenesis, neuronal migration, and axonal elongation. Previous magnetic resonance imaging (MRI studies detected three layers throughout the fetal cerebral wall that showed differences in MR contrasts at 10 gestational weeks (GW, which is one of the earliest ages studied using MRI. Contrary to the MRI studies, histological studies found more layers at this fetal age. The purpose of this work is to study the development of brain structures from an early fetal period to an early second trimester stage using ex vivo MRI and compare it to histology. Special attention was paid to laminar structures in the cerebral wall. T2-weighted imaging was performed on fetal brain specimens ranging from 10 GW to 18 GW on a 4.7 tesla MR scanner. We obtained standard grayscale as well as color-coded images using weighted red-green-blue scales, and compared them with the histological images. Our study confirmed laminar structure in the cerebral wall in all the fetal specimens studied. We found that MRI detected four layers within the cerebral wall as early as 10 GW during the early fetal period (10-13 GW. Early second trimester (15-18 GW was characterized by the emergence of subplate structures and five layers within the cerebral wall. The color-coded images were more useful than the standard grayscale images in detecting the laminar structures. Scans with appropriate parameters from a high tesla MR scanner showed detailed laminar structures even through a very small and thin cerebral wall at 10 GW ex vivo. A combination of high-resolution structural imaging and color-coding processing with histological analysis may be a potential

  7. Automated analysis protocol for high resolution BOLD-fMRI mapping of the fingertip somatotopy in brodmann area 3b.

    Science.gov (United States)

    Pfannmöller, Jörg P; Schweizer, Renate; Lotze, Martin

    2016-02-01

    To introduce a standardized and automatized method for functional MRI (fMRI) examinations of the cortical sensory somatotopy in large samples for investigations of the fingertip somatotopy in the primary somatosensory cortex. At 3 Tesla, T2* (spin-spin relaxation time) weighted images (gradient-echo echo planar imaging, voxel size 1.5 × 1.5 × 2 mm3) were acquired during stimulation of the finger tips for thumb, index and middle finger on both hands, in a group of 18 healthy participants. In addition, structural T1 weighted (magnetization prepared rapid gradient echo, isotropic voxel size 1 mm) and MR-angiography (time of flight, voxel size 0.26 × 0.26 × 0.5 mm3) images were recorded. Boundary based register served to combine movement correction and registration in FreeSurfer Functional analysis stream (FS-Fast), resulting in fine scale corrections, as revealed with FSL Possum (FSL FMRIB Software Library Physics-Oriented Simulated Scanner for Understanding MRI) simulations. Automated data analysis was achieved by inclusion of cytoarchitectonic probability maps for calculation of functional activation in Brodmann area 3b. Draining vessel artifacts were identified using the peak value approach and the MR-angiography. Distances were computed as the shortest connection within the gray matter. The fMRI somatotopic maps agreed with the expected fingertip somatotopy in 63% of the investigated subjects, an improvement of 34% compared with FS-Fast. Artifacts have been removed completely. Adjacent fingertips showed average distances of 8 ± 4.3 mm, and between thumb and middle finger 13.4 ± 4.8 mm was found. Distances for both hands were similar as expected from the characteristics of the fingertip spatial tactile resolution. The introduced evaluation procedure allowed automated analysis of the fingertip representation in excellent agreement with preceding results. © 2015 Wiley Periodicals, Inc.

  8. Design and evaluation of an innovative MRI-compatible Braille stimulator with high spatial and temporal resolution.

    Science.gov (United States)

    Debowska, Weronika; Wolak, Tomasz; Soluch, Pawel; Orzechowski, Mateusz; Kossut, Malgorzata

    2013-02-15

    Neural correlates of Braille reading have been widely studied with different neuroimaging techniques. Nevertheless, the exact brain processes underlying this unique activity are still unknown, due to suboptimal accuracy of imaging and/or stimuli delivery methods. To study somatosensory perception effectively, the stimulation must reflect parameters of the natural stimulus and must be applied with precise timing. In functional magnetic resonance imaging (fMRI) providing these characteristics requires technologically advanced solutions and there have been several successful direct tactile stimulation devices designed that allow investigation of somatotopic organization of brain sensory areas. They may, however, be of limited applicability in studying brain mechanisms related to such distinctive tactile activity as Braille reading. In this paper we describe the design and experimental evaluation of an innovative MRI-compatible Braille Character Stimulator (BCS) enabling precise and stable delivery of standardized Braille characters with high temporal resolution. Our device is fully programmable, flexible in stimuli delivery and can be easily implemented in any research unit. The Braille Character Stimulator was tested with a same-different discrimination task on Braille characters during an event-related fMRI experiment in eleven right-handed sighted adult subjects. The results show significant activations in several cortical areas, including bilateral primary (SI) and secondary somatosensory (SII) cortices, bilateral premotor and supplementary motor areas, inferior frontal gyri, inferior temporal gyri and precuneus, as well as contralateral (to the stimulated hand) thalamus. The results validate the use of the BCS as a method of effective stimuli application in fMRI studies, in both sighted and visually impaired subjects. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Reproducibility and differentiation of cervical arteriopathies using in vivo high-resolution black-blood MRI at 3 T

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Florian; Strobl, Frederik F.; Cyran, Clemens C.; Helck, Andreas D.; Hartmann, Martin; Schindler, Andreas; Reiser, Maximilian F.; Saam, Tobias [Ludwig-Maximilians-University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); Nikolaou, Konstantin [Ludwig-Maximilians-University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); Eberhard-Karls-University Tuebingen, Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2016-06-15

    The aims of the present study are to evaluate the potential of high-resolution black-blood MRI (hr-bb-cMRI) to differentiate common cervical arteriopathies and to evaluate interobserver reproducibility. Forty-three consecutive patients with distinct cervical arteriopathies were examined with cervical hr-bb-cMRI at 3.0 Te with fat-saturated pre- and post-contrast T1w, T2w, and TOF images using dedicated carotid surface coils at our institution. Twenty-three patients had atherosclerotic disease, causing significant stenosis in 12 patients while 11 patients had moderate stenosis. Eight patients presented with cervical vasculitis, and five patients had arterial dissection. Furthermore, seven control subjects with no evidence of carotid disease were included. Two experienced readers blinded to all clinical information reviewed all MR images and classified both carotid and vertebral arteries as affected either by atherosclerosis, dissection, vasculitis, or no disease. Finally, a consensus reading was performed. On a per-vessel level, test performance parameters (sensitivity, specificity, positive predictive value, negative predictive value) were 95, 97.7, 92.9, and 98.5 % for atherosclerotic disease; 91, 100, 100, and 98.7 % for vasculitis; and 100, 100, 100, and 100 % for dissection, respectively. On a per-patient level, performance parameters were 95.7, 85.7, 97.2, and 85.7 % for the diagnosis of atherosclerosis and 100, 100, 100, and 100 % for the diagnosis of dissection and of vasculitis, respectively. Accuracy rates were all above 95 % for all entities. There was a high agreement between observers both in a per-vessel (κ = 0.83) and in a per-patient analysis (κ = 0.82). This study demonstrates that hr-bb-cMRI is able to non-invasively differentiate between the most common cervical arteriopathies with an excellent interreader reproducibility. (orig.)

  10. A non-contrast CMR index for assessing myocardial fibrosis.

    Science.gov (United States)

    Yin, Qian; Abendschein, Dana; Muccigrosso, David; O'Connor, Robert; Goldstein, Thomas; Chen, Ridong; Zheng, Jie

    2017-10-01

    Safe, sensitive, and non-invasive imaging methods to assess the presence, extent, and turnover of myocardial fibrosis are needed for early stratification of risk in patients who might develop heart failure after myocardial infarction. We describe a non-contrast cardiac magnetic resonance (CMR) approach for sensitive detection of myocardial fibrosis using a canine model of myocardial infarction and reperfusion. Seven dogs had coronary thrombotic occlusion of the left anterior descending coronary arteries followed by fibrinolytic reperfusion. CMR studies were performed at 7days after reperfusion. A CMR spin-locking T1ρ mapping sequence was used to acquire T1ρ dispersion data with spin-lock frequencies of 0 and 511Hz. A fibrosis index map was derived on a pixel-by-pixel basis. CMR native T1 mapping, first-pass myocardial perfusion imaging, and post-contrast late gadolinium enhancement imaging were also performed for assessing myocardial ischemia and fibrosis. Hearts were dissected after CMR for histopathological staining and two myocardial tissue segments from the septal regions of adjacent left ventricular slices were qualitatively assessed to grade the extent of myocardial fibrosis. Histopathology of 14 myocardial tissue segments from septal regions was graded as grade 1 (fibrosis area, 50% of field, n=1). A dramatic difference in fibrosis index (183%, PT1 (5.5%, P=0.12), and perfusion (-21%, P=0.05). A non-contrast CMR index based on T1ρ dispersion contrast was shown in preliminary studies to detect and correlate with the extent of myocardial fibrosis identified histopathologically. A non-contrast approach may have important implications for managing cardiac patients with heart failure, particularly in the presence of impaired renal function. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Super-resolution reconstruction in frequency, image, and wavelet domains to reduce through-plane partial voluming in MRI

    Energy Technology Data Exchange (ETDEWEB)

    Gholipour, Ali, E-mail: ali.gholipour@childrens.harvard.edu; Afacan, Onur; Scherrer, Benoit; Prabhu, Sanjay P.; Warfield, Simon K. [Department of Radiology, Boston Children’s Hospital, Boston, Massachusetts 02115 and Harvard Medical School, Boston, Massachusetts 02115 (United States); Aganj, Iman [Radiology Department, Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, Massachusetts 02129 and Harvard Medical School, Boston, Massachusetts 02115 (United States); Sahin, Mustafa [Department of Neurology, Boston Children’s Hospital, Boston, Massachusetts 02115 and Harvard Medical School, Boston, Massachusetts 02115 (United States)

    2015-12-15

    Purpose: To compare and evaluate the use of super-resolution reconstruction (SRR), in frequency, image, and wavelet domains, to reduce through-plane partial voluming effects in magnetic resonance imaging. Methods: The reconstruction of an isotropic high-resolution image from multiple thick-slice scans has been investigated through techniques in frequency, image, and wavelet domains. Experiments were carried out with thick-slice T2-weighted fast spin echo sequence on the Academic College of Radiology MRI phantom, where the reconstructed images were compared to a reference high-resolution scan using peak signal-to-noise ratio (PSNR), structural similarity image metric (SSIM), mutual information (MI), and the mean absolute error (MAE) of image intensity profiles. The application of super-resolution reconstruction was then examined in retrospective processing of clinical neuroimages of ten pediatric patients with tuberous sclerosis complex (TSC) to reduce through-plane partial voluming for improved 3D delineation and visualization of thin radial bands of white matter abnormalities. Results: Quantitative evaluation results show improvements in all evaluation metrics through super-resolution reconstruction in the frequency, image, and wavelet domains, with the highest values obtained from SRR in the image domain. The metric values for image-domain SRR versus the original axial, coronal, and sagittal images were PSNR = 32.26 vs 32.22, 32.16, 30.65; SSIM = 0.931 vs 0.922, 0.924, 0.918; MI = 0.871 vs 0.842, 0.844, 0.831; and MAE = 5.38 vs 7.34, 7.06, 6.19. All similarity metrics showed high correlations with expert ranking of image resolution with MI showing the highest correlation at 0.943. Qualitative assessment of the neuroimages of ten TSC patients through in-plane and out-of-plane visualization of structures showed the extent of partial voluming effect in a real clinical scenario and its reduction using SRR. Blinded expert evaluation of image resolution in

  12. Q-ball imaging models: comparison between high and low angular resolution diffusion-weighted MRI protocols for investigation of brain white matter integrity

    Energy Technology Data Exchange (ETDEWEB)

    Caiazzo, Giuseppina; Trojsi, Francesca; Cirillo, Mario; Tedeschi, Gioacchino [MRI Research Center SUN-FISM-Neurological Institute for Diagnosis and Care ' ' Hermitage Capodimonte' ' , Naples (Italy); Second University of Naples, Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, Naples (Italy); Esposito, Fabrizio [University of Salerno, Department of Medicine and Surgery, Baronissi (Salerno) (Italy); Maastricht University, Department of Cognitive Neuroscience, Maastricht (Netherlands)

    2016-02-15

    Q-ball imaging (QBI) is one of the typical data models for quantifying white matter (WM) anisotropy in diffusion-weighted MRI (DwMRI) studies. Brain and spinal investigation by high angular resolution DwMRI (high angular resolution imaging (HARDI)) protocols exhibits higher angular resolution in diffusion imaging compared to low angular resolution models, although with longer acquisition times. We aimed to assess the difference between QBI-derived anisotropy values from high and low angular resolution DwMRI protocols and their potential advantages or shortcomings in neuroradiology. Brain DwMRI data sets were acquired in seven healthy volunteers using both HARDI (b = 3000 s/mm{sup 2}, 54 gradient directions) and low angular resolution (b = 1000 s/mm{sup 2}, 32 gradient directions) acquisition schemes. For both sequences, tract of interest tractography and generalized fractional anisotropy (GFA) measures were extracted by using QBI model and were compared between the two data sets. QBI tractography and voxel-wise analyses showed that some WM tracts, such as corpus callosum, inferior longitudinal, and uncinate fasciculi, were reconstructed as one-dominant-direction fiber bundles with both acquisition schemes. In these WM tracts, mean percent different difference in GFA between the two data sets was less than 5 %. Contrariwise, multidirectional fiber bundles, such as corticospinal tract and superior longitudinal fasciculus, were more accurately depicted by HARDI acquisition scheme. Our results suggest that the design of optimal DwMRI acquisition protocols for clinical investigation of WM anisotropy by QBI models should consider the specific brain target regions to be explored, inducing researchers to a trade-off choice between angular resolution and acquisition time. (orig.)

  13. Slice-accelerated gradient-echo echo planar imaging dynamic susceptibility contrast-enhanced MRI with blipped CAIPI: effect of increasing temporal resolution.

    Science.gov (United States)

    Takamura, Tomohiro; Hori, Masaaki; Kamagata, Koji; Kumamaru, Kanako K; Irie, Ryusuke; Hagiwara, Akifumi; Hamasaki, Nozomi; Aoki, Shigeki

    2018-01-01

    To assess the influence of high temporal resolution on the perfusion measurements and image quality of perfusion maps, by applying simultaneous-multi-slice acquisition (SMS) dynamic susceptibility contrast-enhanced (DSC) magnetic resonance imaging (MRI). DSC-MRI data using SMS gradient-echo echo planar imaging sequences in 10 subjects with no intracranial abnormalities were retrospectively analyzed. Three additional data sets with temporal resolution of 1.0, 1.5, and 2.0 s were created from the raw data sets of 0.5 s. Cerebral blood flow (CBF), cerebral blood volume, mean transit time (MTT), time to peak (TTP), and time to maximum tissue residue function (T max ) measurements were performed, as was visual perfusion map analysis. The perfusion parameter for temporal resolution of 0.5 s (reference) was compared with each synthesized perfusion parameter. CBF, MTT, and TTP values at temporal resolutions of 1.5 and 2.0 s differed significantly from the reference. The image quality of MTT, TTP, and T max maps deteriorated with decreasing temporal resolution. The temporal resolution of DSC-MRI influences perfusion parameters and SMS DSC-MRI provides better image quality for MTT, TTP, and T max maps.

  14. Improving the Specificity of High Resolution Breast MRI by Optimizing Data Acquisition and Diagnostic Models

    National Research Council Canada - National Science Library

    Partridge, Savannah

    2000-01-01

    .... A high-resolution, three time-point, contrast-enhanced MR technique was optimized for image quality, breast coverage, and time efficiency, and over 200 patients were imaged prior to undergoing surgery...

  15. Anisotropy in high-resolution diffusion-weighted MRI and anomalous diffusion.

    Science.gov (United States)

    Hanyga, A; Seredyńska, M

    2012-07-01

    It is shown below that complex diffusion anisotropy observed in diffusion-weighted MRI can be fully accounted for by allowing for non-locality of the spatial operator in the diffusion equation. The anisotropy is represented by a distribution over directions on a sphere. It allows recognition of fiber tracts crossing at arbitrary angles. A simple generalization of the Stejskal-Tanner equation for the determination of the ODF is presented. Furthermore, an explicit solution of the Bloch-Torrey equation for an anisotropic time-fractional diffusion equation is obtained in terms of a generalized Mittag-Leffler type function. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. A scalable multi-resolution spatio-temporal model for brain activation and connectivity in fMRI data

    KAUST Repository

    Castruccio, Stefano

    2018-01-23

    Functional Magnetic Resonance Imaging (fMRI) is a primary modality for studying brain activity. Modeling spatial dependence of imaging data at different spatial scales is one of the main challenges of contemporary neuroimaging, and it could allow for accurate testing for significance in neural activity. The high dimensionality of this type of data (on the order of hundreds of thousands of voxels) poses serious modeling challenges and considerable computational constraints. For the sake of feasibility, standard models typically reduce dimensionality by modeling covariance among regions of interest (ROIs)—coarser or larger spatial units—rather than among voxels. However, ignoring spatial dependence at different scales could drastically reduce our ability to detect activation patterns in the brain and hence produce misleading results. We introduce a multi-resolution spatio-temporal model and a computationally efficient methodology to estimate cognitive control related activation and whole-brain connectivity. The proposed model allows for testing voxel-specific activation while accounting for non-stationary local spatial dependence within anatomically defined ROIs, as well as regional dependence (between-ROIs). The model is used in a motor-task fMRI study to investigate brain activation and connectivity patterns aimed at identifying associations between these patterns and regaining motor functionality following a stroke.

  17. Recollection, familiarity, and content-sensitivity in lateral parietal cortex: A high-resolution fMRI study

    Directory of Open Access Journals (Sweden)

    Jeffrey D. Johnson

    2013-05-01

    Full Text Available Numerous studies have identified brain regions where activity is consistently correlated with the retrieval (recollection of qualitative episodic information. This ‘core recollection network’ can be contrasted with regions where activity differs according to the contents of retrieval. The present study used high-resolution fMRI to investigate whether these putatively-distinct retrieval processes engage common versus dissociable regions. Subjects studied words with two encoding tasks and then performed a memory test in which they distinguished between recollection and different levels of recognition confidence. The fMRI data from study and test revealed several overlapping regions where activity differed according to encoding task, suggesting that content was selectively reinstated during retrieval. The majority of recollection-related regions, though, did not exhibit reinstatement effects, providing support for a core recollection network. Importantly, lateral parietal cortex demonstrated a clear dissociation, whereby recollection effects were localized to angular gyrus and confidence effects were restricted to intraparietal sulcus. Moreover, the latter region exhibited a non-monotonic pattern, consistent with a neural signal reflecting item familiarity rather than a generic form of memory strength. Together, the findings show that episodic retrieval relies on both content-sensitive and core recollective processes, and these can be differentiated from familiarity-based recognition memory.

  18. A scalable multi-resolution spatio-temporal model for brain activation and connectivity in fMRI data.

    Science.gov (United States)

    Castruccio, Stefano; Ombao, Hernando; Genton, Marc G

    2018-01-22

    Functional Magnetic Resonance Imaging (fMRI) is a primary modality for studying brain activity. Modeling spatial dependence of imaging data at different spatial scales is one of the main challenges of contemporary neuroimaging, and it could allow for accurate testing for significance in neural activity. The high dimensionality of this type of data (on the order of hundreds of thousands of voxels) poses serious modeling challenges and considerable computational constraints. For the sake of feasibility, standard models typically reduce dimensionality by modeling covariance among regions of interest (ROIs)-coarser or larger spatial units-rather than among voxels. However, ignoring spatial dependence at different scales could drastically reduce our ability to detect activation patterns in the brain and hence produce misleading results. We introduce a multi-resolution spatio-temporal model and a computationally efficient methodology to estimate cognitive control related activation and whole-brain connectivity. The proposed model allows for testing voxel-specific activation while accounting for non-stationary local spatial dependence within anatomically defined ROIs, as well as regional dependence (between-ROIs). The model is used in a motor-task fMRI study to investigate brain activation and connectivity patterns aimed at identifying associations between these patterns and regaining motor functionality following a stroke. © 2018, The International Biometric Society.

  19. To Resolve or Not To Resolve, that Is the Question: The Dual-Path Model of Incongruity Resolution and Absurd Verbal Humor by fMRI.

    Science.gov (United States)

    Dai, Ru H; Chen, Hsueh-Chih; Chan, Yu C; Wu, Ching-Lin; Li, Ping; Cho, Shu L; Hu, Jon-Fan

    2017-01-01

    It is well accepted that the humor comprehension processing involves incongruity detection and resolution and then induces a feeling of amusement. However, this three-stage model of humor processing does not apply to absurd humor (so-called nonsense humor). Absurd humor contains an unresolvable incongruity but can still induce a feeling of mirth. In this study, we used functional magnetic resonance imaging (fMRI) to identify the neural mechanisms of absurd humor. Specifically, we aimed to investigate the neural substrates associated with the complete resolution of incongruity resolution humor and partial resolution of absurd humor. Based on the fMRI data, we propose a dual-path model of incongruity resolution and absurd verbal humor. According to this model, the detection and resolution for the incongruity of incongruity resolution humor activate brain regions involved in the temporo-parietal lobe (TPJ) implicated in the integration of multiple information and precuneus, likely to be involved in the ability of perspective taking. The appreciation of incongruity resolution humor activates regions the posterior cingulate cortex (PCC), implicated in autobiographic or event memory retrieval, and parahippocampal gyrus (PHG), implying the funny feeling. By contrast, the partial resolution of absurd humor elicits greater activation in the fusiform gyrus which have been implicated in word processing, inferior frontal gyrus (IFG) for the process of incongruity resolution and superior temporal gyrus (STG) for the pragmatic awareness.

  20. A high resolution 7-Tesla resting-state fMRI test-retest dataset with cognitive and physiological measures.

    Science.gov (United States)

    Gorgolewski, Krzysztof J; Mendes, Natacha; Wilfling, Domenica; Wladimirow, Elisabeth; Gauthier, Claudine J; Bonnen, Tyler; Ruby, Florence J M; Trampel, Robert; Bazin, Pierre-Louis; Cozatl, Roberto; Smallwood, Jonathan; Margulies, Daniel S

    2015-01-01

    Here we present a test-retest dataset of functional magnetic resonance imaging (fMRI) data acquired at rest. 22 participants were scanned during two sessions spaced one week apart. Each session includes two 1.5 mm isotropic whole-brain scans and one 0.75 mm isotropic scan of the prefrontal cortex, giving a total of six time-points. Additionally, the dataset includes measures of mood, sustained attention, blood pressure, respiration, pulse, and the content of self-generated thoughts (mind wandering). This data enables the investigation of sources of both intra- and inter-session variability not only limited to physiological changes, but also including alterations in cognitive and affective states, at high spatial resolution. The dataset is accompanied by a detailed experimental protocol and source code of all stimuli used.

  1. High-resolution MRI vs multislice spiral CT: which technique depicts the trabecular bone structure best?

    Science.gov (United States)

    Link, Thomas M; Vieth, Volker; Stehling, Christoph; Lotter, Albrecht; Beer, Ambros; Newitt, David; Majumdar, Sharmila

    2003-04-01

    The purpose of this study was to compare trabecular bone structure parameters obtained from high-resolution magnetic resonance (HRMR) and multislice computed tomography (MSCT) images with those determined in contact radiographs from corresponding specimen sections. High-resolution MR and MSCT images were obtained in 39 distal radius specimens. For HRMR the in-plane spatial resolution was 0.152x0.153 mm(2) with a slice thickness of 0.9 and 0.3 mm using a 3D T1-weighted spin-echo sequence. For MSCT the resolution was 0.247x0.247 mm(2) with a collimation of 1 mm. Using a diamond saw, 117 0.9- to 1-mm-thick sections were obtained from these specimens and contact radiographs were acquired. In the corresponding sections structure parameters analogous to bone histomorphometry were determined. Significant correlations between MR- and CT-derived structure parameters and those derived from the contact radiographs were found (pbone structure parameters assessed in distal radius HRMR and MSCT images are significantly correlated with those determined in corresponding specimen sections (pbone structure.

  2. High-resolution anatomy of the human brain stem using 7-T MRI: improved detection of inner structures and nerves?

    Energy Technology Data Exchange (ETDEWEB)

    Gizewski, Elke R. [Medical University Innsbruck, Department of Neuroradiology, Innsbruck (Austria); Maderwald, Stefan [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Linn, Jennifer; Bochmann, Katja [LMU Munich, Department of Neuroradiology, Munich (Germany); Dassinger, Benjamin [Medical University Innsbruck, Department of Neuroradiology, Innsbruck (Austria); Justus-Liebig-University Giessen, Department of Neuroradiology, Giessen (Germany); Forsting, Michael [University Hospital, University Duisburg-Essen, Departments of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Ladd, Mark E. [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital, University Duisburg-Essen, Departments of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany)

    2014-03-15

    The purpose of this paper is to assess the value of 7 Tesla (7 T) MRI for the depiction of brain stem and cranial nerve (CN) anatomy. Six volunteers were examined at 7 T using high-resolution SWI, MPRAGE, MP2RAGE, 3D SPACE T2, T2, and PD images to establish scanning parameters targeted at optimizing spatial resolution. Direct comparisons between 3 and 7 T were performed in two additional subjects using the finalized sequences (3 T: T2, PD, MPRAGE, SWAN; 7 T: 3D T2, MPRAGE, SWI, MP2RAGE). Artifacts and the depiction of structures were evaluated by two neuroradiologists using a standardized score sheet. Sequences could be established for high-resolution 7 T imaging even in caudal cranial areas. High in-plane resolution T2, PD, and SWI images provided depiction of inner brain stem structures such as pons fibers, raphe, reticular formation, nerve roots, and periaqueductal gray. MPRAGE and MP2RAGE provided clear depiction of the CNs. 3D T2 images improved depiction of inner brain structure in comparison to T2 images at 3 T. Although the 7-T SWI sequence provided improved contrast to some inner structures, extended areas were influenced by artifacts due to image disturbances from susceptibility differences. Seven-tesla imaging of basal brain areas is feasible and might have significant impact on detection and diagnosis in patients with specific diseases, e.g., trigeminal pain related to affection of the nerve root. Some inner brain stem structures can be depicted at 3 T, but certain sequences at 7 T, in particular 3D SPACE T2, are superior in producing anatomical in vivo images of deep brain stem structures. (orig.)

  3. 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

  4. Sparse Bayesian framework applied to 3D super-resolution reconstruction in fetal brain MRI

    Science.gov (United States)

    Becerra, Laura C.; Velasco Toledo, Nelson; Romero Castro, Eduardo

    2015-01-01

    Fetal Magnetic Resonance (FMR) is an imaging technique that is becoming increasingly important as allows assessing brain development and thus make an early diagnostic of congenital abnormalities, spatial resolution is limited by the short acquisition time and the unpredictable fetus movements, in consequence the resulting images are characterized by non-parallel projection planes composed by anisotropic voxels. The sparse Bayesian representation is a flexible strategy which is able to model complex relationships. The Super-resolution is approached as a regression problem, the main advantage is the capability to learn data relations from observations. Quantitative performance evaluation was carried out using synthetic images, the proposed method demonstrates a better reconstruction quality compared with standard interpolation approach. The presented method is a promising approach to improve the information quality related with the 3-D fetal brain structure. It is important because allows assessing brain development and thus make an early diagnostic of congenital abnormalities.

  5. High resolution MRI for preoperative work-up of neonates with an anorectal malformation: a direct comparison with distal pressure colostography/fistulography.

    Science.gov (United States)

    Thomeer, Maarten G; Devos, Annick; Lequin, Maarten; De Graaf, Nanko; Meeussen, Conny J H M; Meradji, Morteza; De Blaauw, Ivo; Sloots, Cornelius E J

    2015-12-01

    To compare MRI and colostography/fistulography in neonates with anorectal malformations (ARM), using surgery as reference standard. Thirty-three neonates (22 boys) with ARM were included. All patients underwent both preoperative high-resolution MRI (without sedation or contrast instillation) and colostography/fistulography. The Krickenbeck classification was used to classify anorectal malformations, and the level of the rectal ending in relation to the levator muscle was evaluated. Subjects included nine patients with a bulbar recto-urethral fistula, six with a prostatic recto-urethral fistula, five with a vestibular fistula, five with a cloacal malformation, four without fistula, one with a H-type fistula, one with anal stenosis, one with a rectoperineal fistula and one with a bladderneck fistula. MRI and colostography/fistulography predicted anatomy in 88 % (29/33) and 61 % (20/33) of cases, respectively (p = 0.012). The distal end of the rectal pouch was correctly predicted in 88 % (29/33) and 67 % (22/33) of cases, respectively (p = 0.065). The length of the common channel in cloacal malformation was predicted with MRI in all (100 %, 5/5) and in 80 % of cases (4/5) with colostography/fistulography. Two bowel perforations occurred during colostography/fistulography. MRI provides the most accurate evaluation of ARM and should be considered a serious alternative to colostography/fistulography during preoperative work-up. • High-resolution MRI is feasible without the use of sedation or anaesthesia. • MRI is more accurate than colostography/fistulography in visualising the type of ARM. • MRI is as reliable as colostography/fistulography in predicting the level of the rectal pouch. • Colostography/fistulography can be complicated by bowel perforation.

  6. Interactive local super-resolution reconstruction of whole-body MRI mouse data: A pilot study with applications to bone and kidney metastases

    NARCIS (Netherlands)

    O.M. Dzyubachyk (Oleh); A. Khmelinskii (Artem); E. Plenge (Esben); P. Kok (Peter); T.J.A. Snoeks (Thomas); D.H.J. Poot; C.W.G.M. Löwik (Clemens); C.P. Botha (Charl); W.J. Niessen (Wiro); L. van der Weerd; E. Meijering (Erik); B.P.F. Lelieveldt (Boudewijn)

    2014-01-01

    textabstractIn small animal imaging studies, when the locations of the micro-structures of interest are unknown a priori, there is a simultaneous need for full-body coverage and high resolution. In MRI, additional requirements to image contrast and acquisition time will often make it impossible to

  7. Interactive local super-resolution reconstruction of whole-body MRI mouse data : A pilot study with applications to bone and kidney metastases

    NARCIS (Netherlands)

    Dzyubachyk, O.; Khmelinskii, A.; Plenge, E.; Kok, P.; Snoeks, T.J.; Poot, D.H.; Löwik, C.W.; Botha, C.P.; Niessen, W.J.; Van der Weerd, L.; Meijering, E.; Lelieveldt, B.P.F.

    2014-01-01

    In small animal imaging studies, when the locations of the micro-structures of interest are unknown a priori, there is a simultaneous need for full-body coverage and high resolution. In MRI, additional requirements to image contrast and acquisition time will often make it impossible to acquire such

  8. The effect of resolution on viscous dissipation measured with 4D flow MRI in patients with Fontan circulation: Evaluation using computational fluid dynamics

    NARCIS (Netherlands)

    M. Cibiş (Merih); K. Jarvis (Kelly); M. Markl (Michael); M. Rose (Michael); C. Rigsby (Cynthia); A.J. Barker (Alex); J.J. Wentzel (Jolanda)

    2015-01-01

    textabstractViscous dissipation inside Fontan circulation, a parameter associated with the exercise intolerance of Fontan patients, can be derived from computational fluid dynamics (CFD) or 4D flow MRI velocities. However, the impact of spatial resolution and measurement noise on the estimation of

  9. Distinct laterality alterations distinguish mild cognitive impairment and Alzheimer's disease from healthy aging: statistical parametric mapping with high resolution MRI.

    Science.gov (United States)

    Long, Xiaojing; Zhang, Lijuan; Liao, Weiqi; Jiang, Chunxiang; Qiu, Bensheng

    2013-12-01

    Laterality of human brain varies under healthy aging and diseased conditions. The alterations in hemispheric asymmetry may embed distinct biomarkers linked to the disease dynamics. Statistical parametric mapping based on high-resolution magnetic resonance imaging (MRI) and image processing techniques have allowed automated characterization of morphological features across the entire brain. In this study, 149 subjects grouped in healthy young, healthy elderly, mild cognitive impairment (MCI), and Alzheimer's disease (AD) were investigated using multivariate analysis for regional cerebral laterality indexed by surface area, curvature index, cortical thickness, and subjacent white matter volume measured on high-resolution MR images. Asymmetry alteration of MCI and AD were characterized by marked region-specific reduction, while healthy elderly featured a distinct laterality shift in the limbic system in addition to regional asymmetry loss. Lack of the laterality shift in limbic system and early loss of asymmetry in entorhinal cortex may be biomarkers to identify preclinical AD among other dementia. Multivariate analysis of hemispheric asymmetry may provide information helpful for monitoring the disease progress and improving the management of MCI and AD. Copyright © 2012 Wiley Periodicals, Inc.

  10. Musculoskeletal MRI segmentation using multi-resolution simplex meshes with medial representations.

    Science.gov (United States)

    Gilles, Benjamin; Magnenat-Thalmann, Nadia

    2010-06-01

    The automatic segmentation of the musculoskeletal system from medical images is a particularly challenging task, due to its morphological complexity, its large variability in the population and its potentially large deformations. In this paper we propose a novel approach for musculoskeletal segmentation and registration based on simplex meshes. Such discrete models have already proven to be efficient and versatile for medical image segmentation. We extend the current framework by introducing a multi-resolution approach and a reversible medial representation, in order to reduce the complexity of geometric and non-penetration constraints computation. Our framework allows both inter and intra-patient registration (involving both rigid and elastic matching). We also show that the introduced representations facilitate morphological analysis. As a case study, we demonstrate that muscles, bones, ligaments and cartilages of the hip and the thigh can be registered at an interactive frame rate, in a time-efficient way (<30min), with a satisfactory accuracy ( approximately 1.5mm), and with a minimal amount of manual tasks. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  11. Functionally distinct amygdala subregions identified using DTI and high-resolution fMRI

    Science.gov (United States)

    Balderston, Nicholas L.; Schultz, Douglas H.; Hopkins, Lauren

    2015-01-01

    Although the amygdala is often directly linked with fear and emotion, amygdala neurons are activated by a wide variety of emotional and non-emotional stimuli. Different subregions within the amygdala may be engaged preferentially by different aspects of emotional and non-emotional tasks. To test this hypothesis, we measured and compared the effects of novelty and fear on amygdala activity. We used high-resolution blood oxygenation level-dependent (BOLD) imaging and streamline tractography to subdivide the amygdala into three distinct functional subunits. We identified a laterobasal subregion connected with the visual cortex that responds generally to visual stimuli, a non-projecting region that responds to salient visual stimuli, and a centromedial subregion connected with the diencephalon that responds only when a visual stimulus predicts an aversive outcome. We provide anatomical and functional support for a model of amygdala function where information enters through the laterobasal subregion, is processed by intrinsic circuits in the interspersed tissue, and is then passed to the centromedial subregion, where activation leads to behavioral output. PMID:25969533

  12. Segmentation of high angular resolution diffusion MRI using sparse riemannian manifold clustering.

    Science.gov (United States)

    Çetingül, H Ertan; Wright, Margaret J; Thompson, Paul M; Vidal, René

    2014-02-01

    We address the problem of segmenting high angular resolution diffusion imaging (HARDI) data into multiple regions (or fiber tracts) with distinct diffusion properties. We use the orientation distribution function (ODF) to model diffusion and cast the ODF segmentation problem as a clustering problem in the space of ODFs. Our approach integrates tools from sparse representation theory and Riemannian geometry into a graph theoretic segmentation framework. By exploiting the Riemannian properties of the space of ODFs, we learn a sparse representation for each ODF and infer the segmentation by applying spectral clustering to a similarity matrix built from these representations. In cases where regions with similar (resp. distinct) diffusion properties belong to different (resp. same) fiber tracts, we obtain the segmentation by incorporating spatial and user-specified pairwise relationships into the formulation. Experiments on synthetic data evaluate the sensitivity of our method to image noise and to the concentration parameters, and show its superior performance compared to alternative methods when analyzing complex fiber configurations. Experiments on phantom and real data demonstrate the accuracy of the proposed method in segmenting simulated fibers and white matter fiber tracts of clinical importance.

  13. High resolution pituitary gland MRI at 7.0 tesla: a clinical evaluation in Cushing's disease

    Energy Technology Data Exchange (ETDEWEB)

    Rotte, Alexandra A.J. de; Groenewegen, Amy; Rutgers, Dik R.; Witkamp, Theo; Luijten, Peter R.; Hendrikse, Jeroen [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Zelissen, Pierre M.J. [University Medical Center Utrecht, Department of Internal Medicine (Section of Endocrinology), Utrecht (Netherlands); Meijer, F.J.A. [Radboud University Medical Center, Department of Radiology and Nuclear Medicine, Nijmegen (Netherlands); Lindert, Erik J. van [Radboud University Medical Center, Department of Neurosurgery, Nijmegen (Netherlands); Hermus, Ad [Radboud University Medical Center, Department of Internal Medicine (Section of Endocrinology), Nijmegen (Netherlands)

    2016-01-15

    To evaluate the detection of pituitary lesions at 7.0 T compared to 1.5 T MRI in 16 patients with clinically and biochemically proven Cushing's disease. In seven patients, no lesion was detected on the initial 1.5 T MRI, and in nine patients it was uncertain whether there was a lesion. Firstly, two readers assessed both 1.5 T and 7.0 T MRI examinations unpaired in a random order for the presence of lesions. Consensus reading with a third neuroradiologist was used to define final lesions in all MRIs. Secondly, surgical outcome was evaluated. A comparison was made between the lesions visualized with MRI and the lesions found during surgery in 9/16 patients. The interobserver agreement for lesion detection was good at 1.5 T MRI (κ = 0.69) and 7.0 T MRI (κ = 0.62). In five patients, both the 1.5 T and 7.0 T MRI enabled visualization of a lesion on the correct side of the pituitary gland. In three patients, 7.0 T MRI detected a lesion on the correct side of the pituitary gland, while no lesion was visible at 1.5 T MRI. The interobserver agreement of image assessment for 7.0 T MRI in patients with Cushing's disease was good, and lesions were detected more accurately with 7.0 T MRI. (orig.)

  14. Three-dimensional volumetric MRI with isotropic resolution: improved speed of acquisition, spatial resolution and assessment of lesion conspicuity in patients with recurrent soft tissue sarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Ahlawat, Shivani [The Johns Hopkins Medical Institutions, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Morris, Carol [The Johns Hopkins Medical Institutions, Department of Orthopedic Surgery, Baltimore, MD (United States); The Johns Hopkins Medical Institutions, Department of Oncology, Baltimore, MD (United States); Fayad, Laura M. [The Johns Hopkins Medical Institutions, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); The Johns Hopkins Medical Institutions, Department of Orthopedic Surgery, Baltimore, MD (United States); The Johns Hopkins Medical Institutions, Department of Oncology, Baltimore, MD (United States)

    2016-05-15

    To assess the acquisition speed, lesion conspicuity, and inter-observer agreement associated with volumetric T{sub 1}-weighted MR sequences with isotropic resolution for detecting recurrent soft-tissue sarcoma (STS). Fifteen subjects with histologically proven recurrent STS underwent MRI, including axial and coronal T{sub 1}-weighted spin echo (T{sub 1}-WSE) (5-mm slice thickness) and coronal 3D volumetric T{sub 1}-weighted (fat-suppressed, volume-interpolated, breath-hold examination; repetition time/echo time, 3.7/1.4 ms; flip angle, 9.5 ; 1-mm slice thickness) sequences before and after intravenous contrast administration. Subtraction imaging and multiplanar reformations (MPRs) were performed. Acquisition times for T{sub 1}-WSE in two planes and 3D sequences were reported. Two radiologists reviewed images for quality (>50 % artifacts, 25-50 % artifacts, <25 % artifacts, and no substantial artifacts), lesion conspicuity, contrast-to-noise ratio (CNR{sub muscle}), recurrence size, and recurrence-to-joint distance. Descriptive and intraclass correlation (ICC) statistics are given. Mean acquisition times were significantly less for 3D imaging compared with 2-plane T{sub 1}-WSE (183.6 vs 342.6 s; P = 0.012). Image quality was rated as having no substantial artifacts in 13/15 and <25 % artifacts in 2/15. Lesion conspicuity was significantly improved for subtracted versus unsubtracted images (CNR{sub muscle}, 100 ± 138 vs 181 ± 199; P = 0.05). Mean recurrent lesion size was 2.5 cm (range, 0.7-5.7 cm), and measurements on 3D sequences offered excellent interobserver agreement (ICC, 0.98 for lesion size and 0.96 for recurrence-to-joint distance with MPR views). Three-dimensional volumetric sequences offer faster acquisition times, higher spatial resolution, and MPR capability compared with 2D T{sub 1}-WSE for postcontrast imaging. Subtraction imaging provides higher lesion conspicuity for detecting recurrent STS in skeletal muscle, with excellent interobserver

  15. A high-resolution 7-Tesla fMRI dataset from complex natural stimulation with an audio movie

    Science.gov (United States)

    Hanke, Michael; Baumgartner, Florian J.; Ibe, Pierre; Kaule, Falko R.; Pollmann, Stefan; Speck, Oliver; Zinke, Wolf; Stadler, Jörg

    2014-01-01

    Here we present a high-resolution functional magnetic resonance (fMRI) dataset – 20 participants recorded at high field strength (7 Tesla) during prolonged stimulation with an auditory feature film (“Forrest Gump”). In addition, a comprehensive set of auxiliary data (T1w, T2w, DTI, susceptibility-weighted image, angiography) as well as measurements to assess technical and physiological noise components have been acquired. An initial analysis confirms that these data can be used to study common and idiosyncratic brain response patterns to complex auditory stimulation. Among the potential uses of this dataset are the study of auditory attention and cognition, language and music perception, and social perception. The auxiliary measurements enable a large variety of additional analysis strategies that relate functional response patterns to structural properties of the brain. Alongside the acquired data, we provide source code and detailed information on all employed procedures – from stimulus creation to data analysis. In order to facilitate replicative and derived works, only free and open-source software was utilized. PMID:25977761

  16. Measurement of trabecular bone thickness in the limited resolution regime of in vivo MRI by fuzzy distance transform.

    Science.gov (United States)

    Saha, Punam K; Wehrli, Felix W

    2004-01-01

    Trabecular or cancellous bone, the type of bone found in the vertebrae and near the joints of long bones, consists of a network of plates and struts. Accurate measurement of trabecular thickness is of significant interest, for example, to assess the effectiveness of anabolic (bone forming) agents of patients with osteoporosis. Here, we introduce a new fuzzy distance transform (FDT)-based thickness computation method that obviates binary segmentation and that can effectively deal with images acquired at a voxel size comparable to the typical trabecular bone thickness. The method's robustness is shown on the basis of micro-CT images of human trabecular bone, resampled at progressively coarser resolution and after application of rotation and addition of noise as a means to simulate the in vivo situation. Reproducibility of the method is demonstrated with micro-CT images by comparing histograms of thickness within and between data sets and with micro-MRI volume data sets of human volunteers imaged repeatedly. Finally, with in vivo micro-MR images from a prior study in rabbits subjected to corticosteroid exposure, it is demonstrated that short-term treatment resulting in trabecular thinning can be quantified with the new method.

  17. Computation of a high-resolution MRI 3D stereotaxic atlas of the sheep brain.

    Science.gov (United States)

    Ella, Arsène; Delgadillo, José A; Chemineau, Philippe; Keller, Matthieu

    2017-02-15

    The sheep model was first used in the fields of animal reproduction and veterinary sciences and then was utilized in fundamental and preclinical studies. For more than a decade, magnetic resonance (MR) studies performed on this model have been increasingly reported, especially in the field of neuroscience. To contribute to MR translational neuroscience research, a brain template and an atlas are necessary. We have recently generated the first complete T1-weighted (T1W) and T2W MR population average images (or templates) of in vivo sheep brains. In this study, we 1) defined a 3D stereotaxic coordinate system for previously established in vivo population average templates; 2) used deformation fields obtained during optimized nonlinear registrations to compute nonlinear tissues or prior probability maps (nlTPMs) of cerebrospinal fluid (CSF), gray matter (GM), and white matter (WM) tissues; 3) delineated 25 external and 28 internal sheep brain structures by segmenting both templates and nlTPMs; and 4) annotated and labeled these structures using an existing histological atlas. We built a quality high-resolution 3D atlas of average in vivo sheep brains linked to a reference stereotaxic space. The atlas and nlTPMs, associated with previously computed T1W and T2W in vivo sheep brain templates and nlTPMs, provide a complete set of imaging space that are able to be imported into other imaging software programs and could be used as standardized tools for neuroimaging studies or other neuroscience methods, such as image registration, image segmentation, identification of brain structures, implementation of recording devices, or neuronavigation. J. Comp. Neurol. 525:676-692, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. The Effect of Magnetic Field on Positron Range and Spatial Resolution in an Integrated Whole-Body Time-Of-Flight PET/MRI System.

    Science.gov (United States)

    Huang, Shih-Ying; Savic, Dragana; Yang, Jaewon; Shrestha, Uttam; Seo, Youngho

    2014-11-01

    Simultaneous imaging systems combining positron emission tomography (PET) and magnetic resonance imaging (MRI) have been actively investigated. A PET/MR imaging system (GE Healthcare) comprised of a time-of-flight (TOF) PET system utilizing silicon photomultipliers (SiPMs) and 3-tesla (3T) MRI was recently installed at our institution. The small-ring (60 cm diameter) TOF PET subsystem of this PET/MRI system can generate images with higher spatial resolution compared with conventional PET systems. We have examined theoretically and experimentally the effect of uniform magnetic fields on the spatial resolution for high-energy positron emitters. Positron emitters including 18F, 124I, and 68Ga were simulated in water using the Geant4 Monte Carlo toolkit in the presence of a uniform magnetic field (0, 3, and 7 Tesla). The positron annihilation position was tracked to determine the 3D spatial distribution of the 511-keV gammy ray emission. The full-width at tenth maximum (FWTM) of the positron point spread function (PSF) was determined. Experimentally, 18F and 68Ga line source phantoms in air and water were imaged with an investigational PET/MRI system and a PET/CT system to investigate the effect of magnetic field on the spatial resolution of PET. The full-width half maximum (FWHM) of the line spread function (LSF) from the line source was determined as the system spatial resolution. Simulations and experimental results show that the in-plane spatial resolution was slightly improved at field strength as low as 3 Tesla, especially when resolving signal from high-energy positron emitters in the air-tissue boundary.

  19. Potential of computer-aided diagnosis of high spectral and spatial resolution (HiSS) MRI in the classification of breast lesions.

    Science.gov (United States)

    Bhooshan, Neha; Giger, Maryellen; Medved, Milica; Li, Hui; Wood, Abbie; Yuan, Yading; Lan, Li; Marquez, Angelica; Karczmar, Greg; Newstead, Gillian

    2014-01-01

    To compare the performance of computer-aided diagnosis (CADx) analysis of precontrast high spectral and spatial resolution (HiSS) MRI to that of clinical dynamic contrast-enhanced MRI (DCE-MRI) in the diagnostic classification of breast lesions. Thirty-four malignant and seven benign lesions were scanned using two-dimensional (2D) HiSS and clinical 4D DCE-MRI protocols. Lesions were automatically segmented. Morphological features were calculated for HiSS, whereas both morphological and kinetic features were calculated for DCE-MRI. After stepwise feature selection, Bayesian artificial neural networks merged selected features, and receiver operating characteristic (ROC) analysis evaluated the performance with leave-one-lesion-out validation. AUC (area under the ROC curve) values of 0.92 ± 0.06 and 0.90 ± 0.05 were obtained using CADx on HiSS and DCE-MRI, respectively, in the task of classifying benign and malignant lesions. While we failed to show that the higher HiSS performance was significantly better than DCE-MRI, noninferiority testing confirmed that HiSS was not worse than DCE-MRI. CADx of HiSS (without contrast) performed similarly to CADx on clinical DCE-MRI; thus, computerized analysis of HiSS may provide sufficient information for diagnostic classification. The results are clinically important for patients in whom contrast agent is contra-indicated. Even in the limited acquisition mode of 2D single slice HiSS, by using quantitative image analysis to extract characteristics from the HiSS images, similar performance levels were obtained as compared with those from current clinical 4D DCE-MRI. As HiSS acquisitions become possible in 3D, CADx methods can also be applied. Because HiSS and DCE-MRI are based on different contrast mechanisms, the use of the two protocols in combination may increase diagnostic accuracy. Copyright © 2013 Wiley Periodicals, Inc.

  20. Evaluation of carotid atherosclerotic plaque surface characteristics utilizing simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) technique.

    Science.gov (United States)

    Chen, Shuo; Zhao, Huilin; Li, Jifan; Zhou, Zechen; Li, Rui; Balu, Niranjan; Yuan, Chun; Chen, Huijun; Zhao, Xihai

    2017-08-02

    To evaluate the feasibility of the Simultaneous Noncontrast Angiography and intraPlaque hemorrhage (SNAP) technique in identification of carotid plaque surface characteristics compared with the conventional multicontrast vessel wall imaging protocol. Thirty symptomatic patients with carotid plaque were recruited and underwent carotid artery magnetic resonance imaging (MRI) (3.0T) using a conventional multicontrast protocol and SNAP sequence. As an intrinsic multicontrast sequence, SNAP could generate a gray blood reference (Ref) image set, a black blood corrected real (CR) image set, and a bright blood MR angiography (MRA) image set. A bright blood SNAP Ref2 image was implemented by combining Ref and MRA images for facilitating plaque surface characteristics evaluation. The presence/absence of calcification (CA), juxtaluminal calcification (JCA), and ulceration was assessed. The agreement between SNAP and multicontrast vessel wall protocol in identifying CA, JCA, and ulceration was analyzed using Cohen's kappa analysis. The interreader and intrareader reproducibility of SNAP imaging in identifying plaque surface characteristics was also assessed. Good to excellent agreement was found between SNAP and conventional multicontrast protocol in identifying CA (κ = 0.74, 95% confidence interval [CI]: 0.54-0.93), JCA (κ = 0.81, 95% CI: 0.66-0.97), and ulceration (κ = 0.82, 95% CI: 0.65-0.99). In addition, excellent intrareader and interreader reproducibility was found for SNAP imaging in identification of CA, JCA, and ulceration. SNAP imaging showed excellent agreement with multicontrast imaging and high reproducibility in identification of both JCA and ulceration, suggesting that SNAP imaging may be a time-efficient, alternative tool in identification of plaque surface characteristics in carotid arteries. 4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017. © 2017 International Society for Magnetic Resonance in Medicine.

  1. Six-Fold Acceleration of High-Spatial Resolution 3D SPACE MRI of the Knee Through Incoherent k-Space Undersampling and Iterative Reconstruction-First Experience.

    Science.gov (United States)

    Fritz, Jan; Raithel, Esther; Thawait, Gaurav K; Gilson, Wesley; Papp, Derek F

    2016-06-01

    The aim of this study was to prospectively test the hypothesis that 6-fold acceleration of a 3-dimensional (3D) turbo spin echo (TSE) magnetic resonance imaging (MRI) pulse sequence with k-space undersampling and iterative reconstruction is feasible for fast high spatial resolution MRI of the knee, while yielding similar image quality and diagnostic performance when compared with a conventional 2-dimensional (2D) TSE MRI standard. The study was approved by the institutional review board. A 10-minute isotropic 3D TSE knee protocol consisting of accelerated intermediate-weighted (repetition time, 900 milliseconds; echo time, 29 milliseconds; voxel size, 0.5 × 0.5 × 0.5 mm; acquisition time, 4:45 minutes) and fat-saturated T2-weighted (repetition time, 900 milliseconds; echo time, 92 milliseconds; voxel size, 0.5 × 0.5 × 0.5 mm; acquisition time, 5:10 minutes) SPACE (sampling perfection with application optimized contrast using different flip angle evolutions) sequence prototypes was compared against a 20-minute 2D TSE standard protocol. The accelerated SPACE sequences were equipped with an optional variable-density poisson-disc pattern as an undersampling mask. An undersampling factor of 0.17 was chosen (6-fold acceleration compared with an acquisition with full sampling). An iterative, sensitivity encoding-type reconstruction with L1 norm-based regularization term was used. The study was performed on a 3 T MRI system using a 15-channel transmit/receive knee coil. The study groups included 15 asymptomatic volunteers and 15 patient volunteers. Quantitative and qualitative assessments were performed by 2 observers. Outcome variables included signal and contrast-to-noise ratio, image quality, and diagnostic accuracy. Qualitative and quantitative measurements were statistically analyzed using nonparametric tests. P values of less than 0.01 were considered significant. The signal-to-noise ratios of 2D and 3D MRI were similar with the exception of fluid, which was

  2. High resolution MRI for preoperative work-up of neonates with an anorectal malformation: a direct comparison with distal pressure colostography/fistulography

    Energy Technology Data Exchange (ETDEWEB)

    Thomeer, Maarten G. [Erasmus MC, Department of Radiology, Rotterdam (Netherlands); Devos, Annick; Lequin, Maarten; Graaf, Nanko de; Meradji, Morteza [Erasmus MC, Department of Pediatric Radiology, Rotterdam (Netherlands); Meeussen, Conny J.H.M.; Blaauw, Ivo de; Sloots, Cornelius E.J. [Erasmus MC, Department of Pediatric Surgery, Rotterdam (Netherlands)

    2015-12-15

    To compare MRI and colostography/fistulography in neonates with anorectal malformations (ARM), using surgery as reference standard. Thirty-three neonates (22 boys) with ARM were included. All patients underwent both preoperative high-resolution MRI (without sedation or contrast instillation) and colostography/fistulography. The Krickenbeck classification was used to classify anorectal malformations, and the level of the rectal ending in relation to the levator muscle was evaluated. Subjects included nine patients with a bulbar recto-urethral fistula, six with a prostatic recto-urethral fistula, five with a vestibular fistula, five with a cloacal malformation, four without fistula, one with a H-type fistula, one with anal stenosis, one with a rectoperineal fistula and one with a bladderneck fistula. MRI and colostography/fistulography predicted anatomy in 88 % (29/33) and 61 % (20/33) of cases, respectively (p = 0.012). The distal end of the rectal pouch was correctly predicted in 88 % (29/33) and 67 % (22/33) of cases, respectively (p = 0.065). The length of the common channel in cloacal malformation was predicted with MRI in all (100 %, 5/5) and in 80 % of cases (4/5) with colostography/fistulography. Two bowel perforations occurred during colostography/fistulography. MRI provides the most accurate evaluation of ARM and should be considered a serious alternative to colostography/fistulography during preoperative work-up. (orig.)

  3. SU-F-J-93: Automated Segmentation of High-Resolution 3D WholeBrain Spectroscopic MRI for Glioblastoma Treatment Planning

    Energy Technology Data Exchange (ETDEWEB)

    Schreibmann, E; Shu, H [Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA (United States); Cordova, J; Gurbani, S; Holder, C; Cooper, L; Shim, H [Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA (United States)

    2016-06-15

    Purpose: We report on an automated segmentation algorithm for defining radiation therapy target volumes using spectroscopic MR images (sMRI) acquired at nominal voxel resolution of 100 microliters. Methods: Wholebrain sMRI combining 3D echo-planar spectroscopic imaging, generalized auto-calibrating partially-parallel acquisitions, and elliptical k-space encoding were conducted on 3T MRI scanner with 32-channel head coil array creating images. Metabolite maps generated include choline (Cho), creatine (Cr), and N-acetylaspartate (NAA), as well as Cho/NAA, Cho/Cr, and NAA/Cr ratio maps. Automated segmentation was achieved by concomitantly considering sMRI metabolite maps with standard contrast enhancing (CE) imaging in a pipeline that first uses the water signal for skull stripping. Subsequently, an initial blob of tumor region is identified by searching for regions of FLAIR abnormalities that also display reduced NAA activity using a mean ratio correlation and morphological filters. These regions are used as starting point for a geodesic level-set refinement that adapts the initial blob to the fine details specific to each metabolite. Results: Accuracy of the segmentation model was tested on a cohort of 12 patients that had sMRI datasets acquired pre, mid and post-treatment, providing a broad range of enhancement patterns. Compared to classical imaging, where heterogeneity in the tumor appearance and shape across posed a greater challenge to the algorithm, sMRI’s regions of abnormal activity were easily detected in the sMRI metabolite maps when combining the detail available in the standard imaging with the local enhancement produced by the metabolites. Results can be imported in the treatment planning, leading in general increase in the target volumes (GTV60) when using sMRI+CE MRI compared to the standard CE MRI alone. Conclusion: Integration of automated segmentation of sMRI metabolite maps into planning is feasible and will likely streamline acceptance of this

  4. Feasibility and evaluation of dual-source transmit 3D imaging of the orbits: Comparison to high-resolution conventional MRI at 3T

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Achim, E-mail: achim.seeger@gmx.de [Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, Tübingen 72076 (Germany); Schulze, Maximilian, E-mail: maximilian.schulze@med.uni-tuebingen.de [Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, Tübingen 72076 (Germany); Schuettauf, Frank, E-mail: fschuettauf@uni-tuebingen.de [University Eye Hospital, Department of Ophthalmology, Eberhard-Karls-University, Schleichstrasse 12, Tübingen 72076 (Germany); Klose, Uwe, E-mail: uwe.klose@med.uni-tuebingen.de [Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, Tübingen 72076 (Germany); Ernemann, Ulrike, E-mail: ulrike.ernemann@med.uni-tuebingen.de [Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, Tübingen 72076 (Germany); Hauser, Till-Karsten, E-mail: till-karsten.hauser@med.uni-tuebingen.de [Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, Tübingen 72076 (Germany)

    2015-06-15

    Highlights: • Reduced FOV imaging enables a 3D approach for a very fast assessment of the orbits. • Conventional MRI exhibited higher eSNR values and consecutively higher scores for overall image quality in the subjective readers’ analysis. • All pathologies could be detected compared to high-resolution conventional MRI making 3D pTX SPACE to a potential alternative and fast imaging technique. - Abstract: Purpose: To prospectively compare the image quality and diagnostic performance of orbital MR images obtained by using a dual-source parallel transmission (pTX) 3D sequence (Sampling Perfection with Application optimized Contrasts using different flip angle Evolution, SPACE) with the image quality of conventional high-resolution standard protocol for clinical use in patients at 3T. Materials and methods: After obtaining institutional review board approval and patient consent, 32 patients with clinical indication for orbital MRI were examined using a high-resolution conventional sequences and 3D pTX SPACE sequences. Quantitative measurements, image quality of the healthy orbit, incidence of artifacts, and the subjective diagnostic performance to establish diagnosis was rated. Statistical significance was calculated by using a Student's t-test and nonparametric Wilcoxon signed rank test. Results: Length measurements were comparable in the two techniques, 3D pTX SPACE resulted in significant faster image acquisition with higher spatial resolution and less motion artifacts as well as better delineation of the optic nerve sheath. However, estimated contrast-to-noise and signal-to-noise and overall image quality as well as subjective scores of the conventional TSE imaging were rated significantly higher. The conventional MR sequences were the preferred techniques by the readers. Conclusion: This study demonstrates the feasibility of 3D pTX SPACE of the orbit resulting in a rapid acquisition of isotropic high-resolution images. Although no pathology was

  5. Is High Temporal Resolution Achievable for Paediatric Cardiac Acquisitions during Several Heart Beats? Illustration with Cardiac Phase Contrast Cine-MRI.

    Directory of Open Access Journals (Sweden)

    Laurent Bonnemains

    Full Text Available During paediatric cardiac Cine-MRI, data acquired during cycles of different lengths must be combined. Most of the time, Feinstein's model is used to project multiple cardiac cycles of variable lengths into a mean cycle.To assess the effect of Feinstein projection on temporal resolution of Cine-MRI.1/The temporal errors during Feinstein's projection were computed in 306 cardiac cycles fully characterized by tissue Doppler imaging with 6-phase analysis (from a population of 7 children and young adults. 2/The effects of these temporal errors on tissue velocities were assessed by simulating typical tissue phase mapping acquisitions and reconstructions. 3/Myocardial velocities curves, extracted from high-resolution phase-contrast cine images, were compared for the 6 volunteers with lowest and highest heart rate variability, within a population of 36 young adults.1/The mean of temporal misalignments was 30 ms over the cardiac cycle but reached 60 ms during early diastole. 2/During phase contrast MRI simulation, early diastole velocity peaks were diminished by 6.1 cm/s leading to virtual disappearance of isovolumic relaxation peaks. 3/The smoothing and erasing of isovolumic relaxation peaks was confirmed on tissue phase mapping velocity curves, between subjects with low and high heart rate variability (p = 0.05.Feinstein cardiac model creates temporal misalignments that impair high temporal resolution phase contrast cine imaging when beat-to-beat heart rate is changing.

  6. Fast single image super-resolution using estimated low-frequency k-space data in MRI.

    Science.gov (United States)

    Luo, Jianhua; Mou, Zhiying; Qin, Binjie; Li, Wanqing; Yang, Feng; Robini, Marc; Zhu, Yuemin

    2017-07-01

    Single image super-resolution (SR) is highly desired in many fields but obtaining it is often technically limited in practice. The purpose of this study was to propose a simple, rapid and robust single image SR method in magnetic resonance (MR) imaging (MRI). The idea is based on the mathematical formulation of the intrinsic link in k-space between a given (modulus) low-resolution (LR) image and the desired SR image. The method consists of two steps: 1) estimating the low-frequency k-space data of the desired SR image from a single LR image; 2) reconstructing the SR image using the estimated low-frequency and zero-filled high-frequency k-space data. The method was evaluated on digital phantom images, physical phantom MR images and real brain MR images, and compared with existing SR methods. The proposed SR method exhibited a good robustness by reaching a clearly higher PSNR (25.77dB) and SSIM (0.991) averaged over different noise levels in comparison with existing edge-guided nonlinear interpolation (EGNI) (PSNR=23.78dB, SSIM=0.983), zero-filling (ZF) (PSNR=24.09dB, SSIM=0.985) and total variation (TV) (PSNR=24.54dB, SSIM=0.987) methods while presenting the same order of computation time as the ZF method but being much faster than the EGNI or TV method. The average PSNR or SSIM over different slice images of the proposed method (PSNR=26.33 dB or SSIM=0.955) was also higher than the EGNI (PSNR=25.07dB or SSIM=0.952), ZF (PSNR=24.97dB or SSIM=0.950) and TV (PSNR=25.70dB or SSIM=0.953) methods, demonstrating its good robustness to variation in anatomical structure of the images. Meanwhile, the proposed method always produced less ringing artifacts than the ZF method, gave a clearer image than the EGNI method, and did not exhibit any blocking effect presented in the TV method. In addition, the proposed method yielded the highest spatial consistency in the inter-slice dimension among the four methods. This study proposed a fast, robust and efficient single image SR

  7. Automated Quantification of Myocardial Salvage in a Rat Model of Ischemia–Reperfusion Injury Using 3D High‐Resolution Magnetic Resonance Imaging (MRI)

    Science.gov (United States)

    Grieve, Stuart M.; Mazhar, Jawad; Callaghan, Fraser; Kok, Cindy Y.; Tandy, Sarah; Bhindi, Ravinay; Figtree, Gemma A.

    2014-01-01

    Background Quantification of myocardial “area at risk” (AAR) and myocardial infarction (MI) zone is critical for assessing novel therapies targeting myocardial ischemia–reperfusion (IR) injury. Current “gold‐standard” methods perfuse the heart with Evan's Blue and stain with triphenyl tetrazolium chloride (TTC), requiring manual slicing and analysis. We aimed to develop and validate a high‐resolution 3‐dimensional (3D) magnetic resonance imaging (MRI) method for quantifying MI and AAR. Methods and Results Forty‐eight hours after IR was induced, rats were anesthetized and gadopentetate dimeglumine was administered intravenously. After 10 minutes, the coronary artery was re‐ligated and a solution containing iron oxide microparticles and Evan's Blue was infused (for comparison). Hearts were harvested and transversally sectioned for TTC staining. Ex vivo MR images of slices were acquired on a 9.4‐T magnet. T2* data allowed visualization of AAR, with microparticle‐associated signal loss in perfused regions. T1 data demonstrated gadolinium retention in infarcted zones. Close correlation (r=0.92 to 0.94; P<0.05) of MRI and Evan's Blue/TTC measures for both AAR and MI was observed when the combined techniques were applied to the same heart slice. However, 3D MRI acquisition and analysis of whole heart reduced intra‐observer variability compared to assessment of isolated slices, and allowed automated segmentation and analysis, thus reducing interobserver variation. Anatomical resolution of 81 μm3 was achieved (versus ≈2 mm with manual slicing). Conclusions This novel, yet simple, MRI technique allows precise assessment of infarct and AAR zones. It removes the need for tissue slicing and provides opportunity for 3D digital analysis at high anatomical resolution in a streamlined manner accessible for all laboratories already performing IR experiments. PMID:25146703

  8. MR-Imaging of teeth and periodontal apparatus: an experimental study comparing high-resolution MRI with MDCT and CBCT

    Energy Technology Data Exchange (ETDEWEB)

    Gaudino, Chiara; Csernus, Reka; Pham, Mirko; Bendszus, Martin; Rohde, Stefan [University Hospital Heidelberg, Department of Neuroradiology, Heidelberg (Germany); Cosgarea, Raluca; Kim, Ti-Sun [University Hospital Heidelberg, Department of Periodontology, Heidelberg (Germany); Heiland, Sabine [University Hospital Heidelberg, Section of Experimental Radiology, Heidelberg (Germany); Beomonte Zobel, Bruno [University Campus Bio-Medico of Rome, Department of Radiology, Interdisciplinary Center for Biomedical Research, Rome (Italy)

    2011-12-15

    The aim of this study was (1) to assess the ability of magnetic resonance imaging (MRI) to visualize dental and periodontal structures and (2) to compare findings with multidetector computed tomography (MDCT) and cone beam CT (CBCT). Four porcine mandibles were examined with (1) 3T-MRI, (2) MDCT and (3) CBCT. Two observers independently reviewed MR, MDCT and CBCT images and assessed image quality of different dental and periodontal structures. To assess quantitatively the accuracy of the different imaging technique, both observers measured burr holes, previously drilled in the mandibles. Dental structures, e.g. teeth roots, pulpa chamber and dentin, were imaged accurately with all imaging sources. Periodontal space and cortical/trabecular bone were better visualized by MRI (p < 0.001). MRI could excellently display the lamina dura, not detectable with MDCT and only inconstant visible with CBCT (p < 0.001). Burr hole measurements were highly precise with all imaging techniques. This experimental study shows the diagnostic feasibility of MRI in visualization of teeth and periodontal anatomy. Detection of periodontal structures was significantly better with MRI than with MDCT or CBCT. Prospective trials have to evaluate further the potential benefit of MRI in a clinical setting. (orig.)

  9. MR-Imaging of teeth and periodontal apparatus: an experimental study comparing high-resolution MRI with MDCT and CBCT.

    Science.gov (United States)

    Gaudino, Chiara; Cosgarea, Raluca; Heiland, Sabine; Csernus, Réka; Beomonte Zobel, Bruno; Pham, Mirko; Kim, Ti-Sun; Bendszus, Martin; Rohde, Stefan

    2011-12-01

    The aim of this study was (1) to assess the ability of magnetic resonance imaging (MRI) to visualize dental and periodontal structures and (2) to compare findings with multidetector computed tomography (MDCT) and cone beam CT (CBCT). Four porcine mandibles were examined with (1) 3T-MRI, (2) MDCT and (3) CBCT. Two observers independently reviewed MR, MDCT and CBCT images and assessed image quality of different dental and periodontal structures. To assess quantitatively the accuracy of the different imaging technique, both observers measured burr holes, previously drilled in the mandibles. Dental structures, e.g. teeth roots, pulpa chamber and dentin, were imaged accurately with all imaging sources. Periodontal space and cortical/trabecular bone were better visualized by MRI (p < 0.001). MRI could excellently display the lamina dura, not detectable with MDCT and only inconstant visible with CBCT (p < 0.001). Burr hole measurements were highly precise with all imaging techniques. This experimental study shows the diagnostic feasibility of MRI in visualization of teeth and periodontal anatomy. Detection of periodontal structures was significantly better with MRI than with MDCT or CBCT. Prospective trials have to evaluate further the potential benefit of MRI in a clinical setting.

  10. Clues to vascular disorders at non-contrast CT of the chest, abdomen, and pelvis.

    Science.gov (United States)

    Esterson, Yonah B; Berkowitz, Jennifer L; Friedman, Barak; Hines, John J; Shah, Priya K; Grimaldi, Gregory M

    2017-08-01

    Non-contrast chest CT scans are commonly performed while CT scans of the abdomen and pelvis are performed in a select subset of patients; those with limited renal function, an allergy to iodinated contrast, in the setting of suspected renal calculus, retroperitoneal hematoma, common duct calculus, abdominal aortic aneurysm with or without rupture, and in patients undergoing a PET-CT scan. In the absence of intravenous contrast, vascular structures may prove challenging to evaluate, yet their assessment is an important component of every non-contrast CT examination. We describe the key imaging features of both arterial and venous pathology, and review clues and common associated non-vascular findings, which can help the radiologist identify vascular disorders at non-contrast CT. Briefly, alternative imaging options are discussed.

  11. In vivo functional connectome of human brainstem nuclei of the ascending arousal, autonomic, and motor systems by high spatial resolution 7-Tesla fMRI.

    Science.gov (United States)

    Bianciardi, Marta; Toschi, Nicola; Eichner, Cornelius; Polimeni, Jonathan R; Setsompop, Kawin; Brown, Emery N; Hämäläinen, Matti S; Rosen, Bruce R; Wald, Lawrence L

    2016-06-01

    Our aim was to map the in vivo human functional connectivity of several brainstem nuclei with the rest of the brain by using seed-based correlation of ultra-high magnetic field functional magnetic resonance imaging (fMRI) data. We used the recently developed template of 11 brainstem nuclei derived from multi-contrast structural MRI at 7 Tesla as seed regions to determine their connectivity to the rest of the brain. To achieve this, we used the increased contrast-to-noise ratio of 7-Tesla fMRI compared with 3 Tesla and time-efficient simultaneous multi-slice imaging to cover the brain with high spatial resolution (1.1-mm isotropic nominal resolution) while maintaining a short repetition time (2.5 s). The delineated Pearson's correlation-based functional connectivity diagrams (connectomes) of 11 brainstem nuclei of the ascending arousal, motor, and autonomic systems from 12 controls are presented and discussed in the context of existing histology and animal work. Considering that the investigated brainstem nuclei play a crucial role in several vital functions, the delineated preliminary connectomes might prove useful for future in vivo research and clinical studies of human brainstem function and pathology, including disorders of consciousness, sleep disorders, autonomic disorders, Parkinson's disease, and other motor disorders.

  12. High-resolution fMRI of Content-sensitive Subsequent Memory Responses in Human Medial Temporal Lobe

    Science.gov (United States)

    Preston, Alison R.; Bornstein, Aaron M.; Hutchinson, J. Benjamin; Gaare, Meghan E.; Glover, Gary H.; Wagner, Anthony D.

    2009-01-01

    The essential role of the medial temporal lobe (MTL) in long-term memory for individual events is well established, yet important questions remain regarding the mnemonic functions of the component structures that constitute the region. Within the hippocampus, recent functional neuroimaging findings suggest that formation of new memories depends on the den tate gyrus and the CA3 field, whereas the contribution of the subiculum may be limited to retrieval. During encoding, it has been further hypothesized that structures within MTL cortex contribute to encoding in a content-sensitive manner, whereas hippocampal structures may contribute to encoding in a more domain-general manner. In the current experiment, high-resolution fMRI techniques were utilized to assess novelty and subsequent memory effects in MTL subregions for two classes of stimuli—faces and scenes. During scanning, participants performed an incidental encoding (target detection) task with novel and repeated faces and scenes. Subsequent recognition memory was indexed for the novel stimuli encountered during scanning. Analyses revealed voxels sensitive to both novel faces and novel scenes in all MTL regions. However, similar percentages of voxels were sensitive to novel faces and scenes in perirhinal cortex, entorhinal cortex, and a combined region comprising the dentate gyrus, CA2, and CA3, whereas parahippocampal cortex, CA1, and subiculum demonstrated greater sensitivity to novel scene stimuli. Paralleling these findings, subsequent memory effects in perirhinal cortex were observed for both faces and scenes, with the magnitude of encoding activation being related to later memory strength, as indexed by a graded response tracking recognition confidence, whereas subsequent memory effects were scene-selective in parahippocampal cortex. Within the hippocampus, encoding activation in the subiculum correlated with subsequent memory for both stimulus classes, with the magnitude of encoding activation varying

  13. Noncontrast computed tomography in obstructive anuria: a prospective study.

    Science.gov (United States)

    Shokeir, Ahmed A; Shoma, Ahmed M; Mosbah, Ahmed; Mansour, Osama; Abol-Ghar, Mohamed; Eassa, Waleed; El-Asmy, Ahmed

    2002-06-01

    To evaluate the role of noncontrast computed tomography (NCCT) in the determination of the cause of obstructive anuria and to compare its accuracy with that of the traditional methods of combined plain abdominal x-ray (KUB) and gray-scale abdominal ultrasonography (US). The study included 40 consecutive patients with obstructive anuria. In addition to the routine evaluation, which included history, clinical examination, biochemical profile, KUB, and US, all patients underwent NCCT. The study patients were tested against an age and sex-matched control group that included the normal contralateral kidneys of 57 consecutive patients who underwent KUB, US, and NCCT for acute flank pain during the same study period. The reference standard for the determination of the cause of obstruction was retrograde or antegrade ureterography with or without ureteroscopy or open surgery. The absence of obstruction in the control group was confirmed by nonequivocal normal intravenous urography of the side free of flank pain. Both NCCT and combined KUB and US were compared regarding the sensitivity, specificity, and overall accuracy. The study group had 48 renal units, because obstruction was bilateral in 8 patients and of a solitary kidney in 32. Of the 42 renal units with calculus obstruction, the site of stone impaction was identified in all renal units by NCCT (sensitivity 100%) and in only 25 by combined KUB and US (sensitivity 59.5%)-a significant difference (P = 0.0001). Of the 6 renal units with noncalcular obstruction, both NCCT and US diagnosed the cause of obstruction in 3. The overall sensitivity of NCCT in the determination of the cause of obstructive anuria was 94% and that of combined KUB and US was 58%-a significant difference (P = 0.0001). The specificity of NCCT was not significantly different from that of combined KUB and US (96.5% versus 93%, respectively). The overall accuracy of NCCT was 95% and that of combined KUB and US was 77%-a significant difference (P = 0

  14. Integration of myocardial scar identified by preoperative delayed contrast-enhanced MRI into a high-resolution mapping system for planning and guidance of VT ablation procedures

    Science.gov (United States)

    Rettmann, M. E.; Suzuki, A.; Wang, S.; Pottinger, N.; Arter, J.; Netzer, A.; Parker, K.; Viker, K.; Packer, D. L.

    2017-03-01

    Myocardial scarring creates a substrate for reentrant circuits which can lead to ventricular tachycardia. In ventricular catheter ablation therapy, regions of myocardial scarring are targeted to interrupt arrhythmic electrical pathways. Low voltage regions are a surrogate for myocardial scar and are identified by generating an electro anatomic map at the start of the procedure. Recent efforts have focussed on integration of preoperative scar information generated from delayed contrast-enhanced MR imaging to augment intraprocedural information. In this work, we describe an initial feasibility study of integration of a preoperative MRI derived scar maps into a high-resolution mapping system to improve planning and guidance of VT ablation procedures.

  15. The prognostic significance of postchemoradiotherapy high-resolution MRI and histopathology detected extramural venous invasion in rectal cancer.

    Science.gov (United States)

    Chand, Manish; Evans, Jessica; Swift, Robert I; Tekkis, Paris P; West, Nicholas P; Stamp, Gordon; Heald, Richard J; Brown, Gina

    2015-03-01

    This study aimed to determine the prognostic significance of extramural venous invasion (EMVI) after chemoradiotherapy (CRT) by both magnetic resonance imaging (MRI) (ymrEMVI) and histopathology (ypEMVI). EMVI is a prognostic factor in rectal cancer but whether this remains so after CRT preoperative is unknown. Histopathological definitions of EMVI are variable and lead to underreporting particularly after CRT. All consecutive patients staged on initial MRI as EMVI-positive undergoing preoperative CRT and curative surgery between Jan 2006 and Jan 2012 were included. Posttreatment EMVI status (yEMVI) was reevaluated for both MRI and pathology. The primary endpoint of disease-free survival (DFS) for ymrEMVI and ypEMVI was calculated using the Kaplan-Meier product limit and compared with a Mantel-Cox log-rank test. A P histopathology tumor characteristics. A total of 188 patients who had evidence of EMVI on initial baseline MRI staging were included. MRI detected significantly more patients with persistent EMVI than histopathology (53% vs 19%) but both were prognostic for worse survival-ymrEMVI (HR 1.97) and ypEMVI (HR 2.39). Patients with persistent ymrEMVI-positivity had significantly worse DFS at 3 years (42.7%) compared with ymrEMVI-negative tumors (79.8%); DFS for was 36.9% versus 65.9% positive and negative ypEMVI, respectively. Detection of EMVI post-CRT is prognostically significant whether detected by MRI or histopathology. EMVI status after treatment may be used to counsel patients regarding ongoing risks of metastatic disease, implications for surveillance, and systemic chemotherapy.

  16. Value of non-contrast CT examination of the urinary tract (stone ...

    African Journals Online (AJOL)

    Mohamed Samir Shaaban

    2015-09-04

    Sep 4, 2015 ... Abstract Background: Urolithiasis is one of the most common urinary tract diseases worldwide, with a wide range of affected age groups. Non-contrast CT examination of the urinary tract is the gold-standard examination for detection and characterization of urinary tract stones, with great impact upon the ...

  17. Value of non-contrast CT examination of the urinary tract (stone ...

    African Journals Online (AJOL)

    Background: Urolithiasis is one of the most common urinary tract diseases worldwide, with a wide range of affected age groups. Non-contrast CT examination of the urinary tract is the gold-standard examination for detection and characterization of urinary tract stones, with great impact upon the choice of method of ...

  18. High-Resolution fMRI of Auditory Cortical Map Changes in Unilateral Hearing Loss and Tinnitus

    NARCIS (Netherlands)

    Ghazaleh, Naghmeh; Van der Zwaag, W.; Clarke, Stephanie; Ville, Dimitri Van De; Maire, Raphael; Saenz, Melissa

    2017-01-01

    Animal models of hearing loss and tinnitus observe pathological neural activity in the tonotopic frequency maps of the primary auditory cortex. Here, we applied ultra high-field fMRI at 7 T to test whether human patients with unilateral hearing loss and tinnitus also show altered functional activity

  19. High-resolution intracranial vessel wall MRI in an elderly asymptomatic population: comparison of 3T and 7T

    Energy Technology Data Exchange (ETDEWEB)

    Harteveld, Anita A.; Kolk, Anja G. van der; Dieleman, Nikki; Siero, Jeroen C.W.; Luijten, Peter R.; Zwanenburg, Jaco J.M.; Hendrikse, Jeroen [University Medical Center Utrecht, Department of Radiology, Postbox 85500, Utrecht (Netherlands); Worp, H.B. van der; Frijns, Catharina J.M. [University Medical Center Utrecht, Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, Utrecht (Netherlands); Kuijf, Hugo J. [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands)

    2017-04-15

    Several intracranial vessel wall sequences have been described in recent literature, with either 3-T or 7-T magnetic resonance imaging (MRI). In the current study, we compared 3-T and 7-T MRI in visualising both the intracranial arterial vessel wall and vessel wall lesions. Twenty-one elderly asymptomatic volunteers were scanned by 3-T and 7-T MRI with an intracranial vessel wall sequence, both before and after contrast administration. Two raters scored image quality, and presence and characteristics of vessel wall lesions. Vessel wall visibility was equal or significantly better at 7 T for the studied arterial segments, even though there were more artefacts hampering assessment. The better visualisation of the vessel wall at 7 T was most prominent in the proximal anterior cerebral circulation and the posterior cerebral artery. In the studied elderly asymptomatic population, 48 vessel-wall lesions were identified at 3 T, of which 7 showed enhancement. At 7 T, 79 lesions were identified, of which 29 showed enhancement. Seventy-one percent of all 3-T lesions and 59 % of all 7-T lesions were also seen at the other field strength. Despite the large variability in detected lesions at both field strengths, we believe 7-T MRI has the highest potential to identify the total burden of intracranial vessel wall lesions. (orig.)

  20. Does low-field dedicated extremity MRI (E-MRI) reliably detect bone erosions in rheumatoid arthritis? A comparison of two different E-MRI units and conventional radiography with high-resolution CT scanning

    DEFF Research Database (Denmark)

    Duer-Jensen, A; Ejbjerg, B; Albrecht-Beste, E

    2008-01-01

    underwent CR, CT and two E-MRI examinations (Esaote Biomedica Artoscan and MagneVu MV1000) of one hand during a 2-week period. In all modalities, each bone of the wrist and MCP joints was blindly evaluated for erosions. MagneVu images were also assessed for the proportion of each bone being visualised...

  1. Does low-field dedicated extremity MRI (E-MRI) reliably detect RA bone erosions? A comparison of two different E-MRI units and conventional radiography with high resolution CT

    DEFF Research Database (Denmark)

    Duer, Anne; Ejbjerg, Bo; Albrecht-Beste, Elisabeth

    2008-01-01

    underwent, within 2 weeks, CR, CT and two E-MRI (Esaote Biomedica; Artoscan and MagneVu; MV1000) examination of one hand. In all modalities each bone of wrist and (MCP) joints was blindedly evaluated for erosions. Furthermore, MagneVu images were assessed for the proportion of each bone being visualized...

  2. Depiction of Achilles Tendon Microstructure In-Vivo Using High-Resolution 3D Ultrashort Echo-Time MRI at 7T

    Science.gov (United States)

    Han, Misung; Larson, Peder E. Z.; Liu, Jing; Krug, Roland

    2014-01-01

    Objectives To demonstrate the feasibility of depicting the internal structure of the Achilles tendon in vivo using high-resolution 3D ultrashort echo-time (UTE) magnetic resonance imaging (MRI) at 7T. Materials and Methods For our UTE imaging, a minimum-phase radiofrequency pulse and an anisotropic field-of-view 3D radial acquisition were used to minimize the echo time and scan time. A fat saturation pulse was applied every eight spoke acquisitions to reduce blurring and chemical shift artifacts from fat and to improve dynamic range of the tendon signal. Five healthy volunteers and one patient were scanned with an isotropic spatial resolution of up to 0.6 mm. Fat-suppressed UTE images were qualitatively evaluated and compared to non-fat-suppressed UTE images and longer echo-time images. Results High-resolution UTE imaging was able to visualize the microstructure of the Achilles tendon. Fat suppression substantially improved the depiction of the internal structure. The UTE images revealed a fascicular pattern in the Achilles tendon and fibrocartilage at the tendon insertion. In a patient who had tendon elongation surgery after birth there was clear depiction of disrupted tendon structure. Conclusions High-resolution fat-suppressed 3D UTE imaging at 7T allows for evaluation of the Achilles tendon microstructure in vivo. PMID:24500089

  3. Carotid artery dissection on non-contrast CT: Does color improve the diagnostic confidence?

    Energy Technology Data Exchange (ETDEWEB)

    Saba, Luca, E-mail: lucasaba@tiscali.it [Department of Radiology, Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari – Polo di Monserrato, s.s. 554 Monserrato, Cagliari 09045 (Italy); Argiolas, Giovanni Maria [Department of Radiology, Azienda Ospedaliero Brotzu (A.O.B.), di Cagliari, Cagliari 09100 (Italy); Raz, Eytan [Department of Radiology, New York University School of Medicine, New York (United States); Department of Neurology and Psychiatry, Sapienza University of Rome (Italy); Sannia, Stefano [Department of Radiology, Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari – Polo di Monserrato, s.s. 554 Monserrato, Cagliari 09045 (Italy); Suri, Jasjit S. [Diagnostic and Monitoring Division, AtheroPointTM LLC, Roseville, CA (United States); Electrical Engineering Department (Aff.), Idaho State University, ID (United States); Siotto, Paolo [Department of Radiology, Azienda Ospedaliero Brotzu (A.O.B.), di Cagliari, Cagliari 09100 (Italy); Sanfilippo, Roberto; Montisci, Roberto [Department of Vascular Surgery, Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari – Polo di Monserrato, s.s. 554 Monserrato, Cagliari 09045 (Italy); Piga, Mario [Department of Radiology, Azienda Ospedaliero Universitaria (A.O.U.), di Cagliari – Polo di Monserrato, s.s. 554 Monserrato, Cagliari 09045 (Italy); Wintermark, Max [Department of Radiology, Neuroradiology Division, University of Virginia, Box 800170, Charlottesville, VA, 22908 (United States)

    2014-12-15

    Highlights: • The use of a color scale to display the non-contrast CT images in lieu of the classic grayscale improves the diagnostic confidence of the readers. • Radiologists should consider the use of a color scale, rather than the conventional grayscale, to assess non-contrast CT studies for possible carotid artery dissection. - Abstract: Purpose: The purpose of this work was to evaluate if the use of color maps, instead of conventional grayscale images, would improve the observer's diagnostic confidence in the non-contrast CT evaluation of internal carotid artery dissection (ICAD). Materials and methods: One hundred patients (61 men, 39 women; mean age, 51 years; range, 25–78 years), 40 with and 60 without ICAD, underwent non-contrast CT and were included in this the retrospective study. In this study, three groups of patients were considered: patients with MR confirmation of ICAD, n = 40; patients with MR confirmation of ICAD absence, n = 20; patients who underwent CT of the carotid arteries because of atherosclerotic disease, n = 40. Four blinded observers with different levels of expertise (expert, intermediate A, intermediate B and trainee) analyzed the non-contrast CT datasets using a cross model (one case grayscale and the following case using the color scale). The presence of ICAD was scored on a 5-point scale in order to assess the observer's diagnostic confidence. After 3 months the four observers evaluated the same datasets by using the same cross-model for the alternate readings (one case color scale and the following case using the grayscale). Statistical analysis included receiver operating characteristics (ROC) curve analysis, the Cohen weighted test and sensitivity, specificity, PPV, NPV, accuracy, LR+ and LR−. Results: The ROC curve analysis showed that, for all observers, the use of color scale resulted in an improved diagnostic confidence with AUC values increasing from 0.896 to 0.936, 0.823 to 0.849, 0.84 to 0.909 and 0

  4. Enhancement of temporal resolution and BOLD sensitivity in real-time fMRI using multi-slab echo-volumar imaging.

    Science.gov (United States)

    Posse, Stefan; Ackley, Elena; Mutihac, Radu; Rick, Jochen; Shane, Matthew; Murray-Krezan, Cristina; Zaitsev, Maxim; Speck, Oliver

    2012-05-15

    In this study, a new approach to high-speed fMRI using multi-slab echo-volumar imaging (EVI) is developed that minimizes geometrical image distortion and spatial blurring, and enables nonaliased sampling of physiological signal fluctuation to increase BOLD sensitivity compared to conventional echo-planar imaging (EPI). Real-time fMRI using whole brain 4-slab EVI with 286 ms temporal resolution (4mm isotropic voxel size) and partial brain 2-slab EVI with 136 ms temporal resolution (4×4×6 mm(3) voxel size) was performed on a clinical 3 Tesla MRI scanner equipped with 12-channel head coil. Four-slab EVI of visual and motor tasks significantly increased mean (visual: 96%, motor: 66%) and maximum t-score (visual: 263%, motor: 124%) and mean (visual: 59%, motor: 131%) and maximum (visual: 29%, motor: 67%) BOLD signal amplitude compared with EPI. Time domain moving average filtering (2s width) to suppress physiological noise from cardiac and respiratory fluctuations further improved mean (visual: 196%, motor: 140%) and maximum (visual: 384%, motor: 200%) t-scores and increased extents of activation (visual: 73%, motor: 70%) compared to EPI. Similar sensitivity enhancement, which is attributed to high sampling rate at only moderately reduced temporal signal-to-noise ratio (mean: -52%) and longer sampling of the BOLD effect in the echo-time domain compared to EPI, was measured in auditory cortex. Two-slab EVI further improved temporal resolution for measuring task-related activation and enabled mapping of five major resting state networks (RSNs) in individual subjects in 5 min scans. The bilateral sensorimotor, the default mode and the occipital RSNs were detectable in time frames as short as 75 s. In conclusion, the high sampling rate of real-time multi-slab EVI significantly improves sensitivity for studying the temporal dynamics of hemodynamic responses and for characterizing functional networks at high field strength in short measurement times. Copyright © 2012

  5. Heart MRI

    Science.gov (United States)

    Magnetic resonance imaging - cardiac; Magnetic resonance imaging - heart; Nuclear magnetic resonance - cardiac; NMR - cardiac; MRI of the heart; Cardiomyopathy - MRI; Heart failure - MRI; Congenital heart disease - MRI

  6. Characterization of high-resolution Gradient Echo and Spin Echo EPI for fMRI in the human visual cortex at 7T.

    Science.gov (United States)

    Rua, Catarina; Costagli, Mauro; Symms, Mark R; Biagi, Laura; Donatelli, Graziella; Cosottini, Mirco; Del Guerra, Alberto; Tosetti, Michela

    2017-07-01

    The increased signal-to-noise ratio (SNR) offered by functional Magnetic Resonance Imaging (fMRI) at 7T allows the acquisition of functional data at sub-millimetric spatial resolutions. However, simply reducing partial volume effects is not sufficient to precisely localize task-induced activation due to the indirect mechanisms that relate brain function and the changes in the measured signal. In this work T2* and T2 weighted Echo Planar Imaging (EPI) schemes based on Gradient Recalled Echo (GRE) and Spin Echo (SE) were evaluated in terms of temporal SNR, percent signal change, contrast to noise ratio (CNR), activation volume, and sensitivity and specificity to gray matter. Datasets were acquired during visual stimulation at in-plane resolutions ranging between 1.5×1.5mm(2) and 0.75×0.75mm(2) targeting the early visual cortex. While similar activation foci were obtained in all acquisitions, at in-plane resolutions of 1.0×1.0mm(2) and larger voxel sizes the T2 weighted contrast of SE-EPI allowed the identification of the activation site with better spatial accuracy. However, at sub-millimetric resolutions the decrease in temporal SNR significantly hampered the sensitivity and the extent of the activation site. On the other hand, high resolution T2* weighted data collected with GRE-EPI provided higher CNR and sensitivity, benefiting from the decreased physiological and partial volume effects. However, spurious activations originating from regions of blood drainage were still present in GRE data, and simple thresholding techniques were found to be inadequate for the removal of such contributions. The combination of 2-class and 3-class automated segmentations, performed directly in EPI space, allowed the selection of active voxels in gray matter. This approach could enable GRE-EPI to accurately map functional activity with satisfactory CNR and specificity to the true site of activation. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. 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.)

  8. A robust multi-shot scan strategy for high-resolution diffusion weighted MRI enabled by multiplexed sensitivity-encoding (MUSE).

    Science.gov (United States)

    Chen, Nan-Kuei; Guidon, Arnaud; Chang, Hing-Chiu; Song, Allen W

    2013-05-15

    Diffusion weighted magnetic resonance imaging (DWI) data have been mostly acquired with single-shot echo-planar imaging (EPI) to minimize motion induced artifacts. The spatial resolution, however, is inherently limited in single-shot EPI, even when the parallel imaging (usually at an acceleration factor of 2) is incorporated. Multi-shot acquisition strategies could potentially achieve higher spatial resolution and fidelity, but they are generally susceptible to motion-induced phase errors among excitations that are exacerbated by diffusion sensitizing gradients, rendering the reconstructed images unusable. It has been shown that shot-to-shot phase variations may be corrected using navigator echoes, but at the cost of imaging throughput. To address these challenges, a novel and robust multi-shot DWI technique, termed multiplexed sensitivity-encoding (MUSE), is developed here to reliably and inherently correct nonlinear shot-to-shot phase variations without the use of navigator echoes. The performance of the MUSE technique is confirmed experimentally in healthy adult volunteers on 3Tesla MRI systems. This newly developed technique should prove highly valuable for mapping brain structures and connectivities at high spatial resolution for neuroscience studies. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. The Clinical Value of High-Intensity Signals on the Coronary Atherosclerotic Plaques: Noncontrast T1-Weighted Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Shoichi Ehara

    2016-07-01

    Full Text Available Over the past several decades, significant progress has been made in the pathohistological assessment of vulnerable plaques and in invasive intravascular imaging techniques. However, the assessment of plaque morphology by invasive modalities is of limited value for the detection of subclinical coronary atherosclerosis and the subsequent prediction or prevention of acute cardiovascular events. Recently, magnetic resonance (MR imaging technology has reached a sufficient level of spatial resolution, which allowed the plaque visualization of large and static arteries such as the carotids and aorta. However, coronary wall imaging by MR is still challenging due to the small size of coronary arteries, cardiac and respiratory motion, and the low contrast-to-noise ratio between the coronary artery wall and the surrounding structures. Following the introduction of carotid plaque imaging with noncontrast T1-weighted imaging (T1WI, some investigators have reported that coronary artery high-intensity signals on T1WI are associated with vulnerable plaque morphology and an increased risk of future cardiac events. Although there are several limitations and issues that need to be resolved, this novel MR technique for coronary plaque imaging could influence treatment strategies for atherothrombotic disease and may be useful for understanding the pathophysiological mechanisms of atherothrombotic plaque formation.

  10. Multiple Somatotopic Representations of Heat and Mechanical Pain in the Operculo-Insular Cortex: A High-Resolution fMRI Study

    Science.gov (United States)

    Iannetti, Gian Domenico; Zambreanu, Laura; Stoeter, Peter; Treede, Rolf-Detlef; Tracey, Irene

    2010-01-01

    Whereas studies of somatotopic representation of touch have been useful to distinguish multiple somatosensory areas within primary (SI) and secondary (SII) somatosensory cortex regions, no such analysis exists for the representation of pain across nociceptive modalities. Here we investigated somatotopy in the operculo-insular cortex with noxious heat and pinprick stimuli in 11 healthy subjects using high-resolution (2 × 2 × 4 mm) 3T functional magnetic resonance imaging (fMRI). Heat stimuli (delivered using a laser) and pinprick stimuli (delivered using a punctate probe) were directed to the dorsum of the right hand and foot in a balanced design. Locations of the peak fMRI responses were compared between stimulation sites (hand vs. foot) and modalities (heat vs. pinprick) within four bilateral regions of interest: anterior and posterior insula and frontal and parietal operculum. Importantly, all analyses were performed on individual, non-normalized fMRI images. For heat stimuli, we found hand-foot somatotopy in the contralateral anterior and posterior insula [hand, 9 ± 10 (SD) mm anterior to foot, P < 0.05] and in the contralateral parietal operculum (SII; hand, 7 ±10 mm lateral to foot, P < 0.05). For pinprick stimuli, we also found somatotopy in the contralateral posterior insula (hand, 9 ±10 mm anterior to foot, P < 0.05). Furthermore, the response to heat stimulation of the hand was 11 ± 12 mm anterior to the response to pinprick stimulation of the hand in the contralateral (left) anterior insula (P < 0.05). These results indicate the existence of multiple somatotopic representations for pain within the operculo-insular region in humans, possibly reflecting its importance as a sensory-integration site that directs emotional responses and behavior appropriately depending on the body site being injured. PMID:20739597

  11. Improved clinical workflow for simultaneous whole-body PET/MRI using high-resolution CAIPIRINHA-accelerated MR-based attenuation correction.

    Science.gov (United States)

    Freitag, Martin T; Fenchel, Matthias; Bäumer, Philipp; Heußer, Thorsten; Rank, Christopher M; Kachelrieß, Marc; Paech, Daniel; Kopka, Klaus; Bickelhaupt, Sebastian; Dimitrakopoulou-Strauss, Antonia; Maier-Hein, Klaus; Floca, Ralf; Ladd, Mark E; Schlemmer, Heinz-Peter; Maier, Florian

    2017-11-01

    To explore the value and reproducibility of a novel magnetic resonance based attenuation correction (MRAC) using a CAIPIRINHA-accelerated T1-weighted Dixon 3D-VIBE sequence for whole-body PET/MRI compared to the clinical standard. The PET raw data of 19 patients from clinical routine were reconstructed with standard MRAC (MRACstd) and the novel MRAC (MRACcaipi), a prototype CAIPIRINHA accelerated Dixon 3D-VIBE sequence, both acquired in 19 s/bed position. Volume of interests (VOIs) for liver, lung and all voxels of the total image stack were created to calculate standardized uptake values (SUVmean) followed by inter-method agreement (Passing-Bablok regression, Bland-Altman analysis). A voxel-wise SUV comparison per patient was performed for intra-individual correlation between MRACstd and MRACcaipi. Difference images (MRACstd-MRACcaipi) of attenuation maps and SUV images were calculated. The image quality of in/opposed-phase water and fat images obtained from MRACcaipi was assessed by two readers on a 5-point Likert-scale including intra-class coefficients for inter-reader agreement. SUVmean correlations of VOIs demonstrated high linearity (0.95attenuation correction by providing a high spatial resolution DIXON-based dataset suited for diagnostic assessment towards time-efficient whole-body PET/MRI. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Cerebellar Ataxia with Complete Clinical Recovery and Resolution of MRI Lesions Related to Central Pontine Myelinolysis: Case Report and Literature Review

    Directory of Open Access Journals (Sweden)

    Cristina Dolciotti

    2010-12-01

    Full Text Available There are several reports of central pontine myelinolysis (CPM in a setting of malnutrition, alcoholism, and chronic debilitating illness associated with electrolyte abnormalities, especially hyponatremia. The cause of myelinolysis is still under debate, and, although osmotic effects are thought to be responsible in most cases, alternative pathological factors should be considered [King et al.: Am J Med Sci 2010;339:561–567]. We report a case of CPM in a patient with recent chemotherapy for colon cancer without electrolyte unbalance and otherwise unexplained causes. Moreover, the present case is an example of the unusual clinical ataxic variant, followed by complete recovery without any specific treatment. The diagnosis was confirmed by MRI, which showed a characteristic hyperintense signal abnormality in the central part of the pons with an unaffected outer rim. One month later, we observed complete resolution of clinical and radiological symptoms.

  13. Distinct prediction errors in mesostriatal circuits of the human brain mediate learning about the values of both states and actions: evidence from high-resolution fMRI.

    Science.gov (United States)

    Colas, Jaron T; Pauli, Wolfgang M; Larsen, Tobias; Tyszka, J Michael; O'Doherty, John P

    2017-10-01

    Prediction-error signals consistent with formal models of "reinforcement learning" (RL) have repeatedly been found within dopaminergic nuclei of the midbrain and dopaminoceptive areas of the striatum. However, the precise form of the RL algorithms implemented in the human brain is not yet well determined. Here, we created a novel paradigm optimized to dissociate the subtypes of reward-prediction errors that function as the key computational signatures of two distinct classes of RL models-namely, "actor/critic" models and action-value-learning models (e.g., the Q-learning model). The state-value-prediction error (SVPE), which is independent of actions, is a hallmark of the actor/critic architecture, whereas the action-value-prediction error (AVPE) is the distinguishing feature of action-value-learning algorithms. To test for the presence of these prediction-error signals in the brain, we scanned human participants with a high-resolution functional magnetic-resonance imaging (fMRI) protocol optimized to enable measurement of neural activity in the dopaminergic midbrain as well as the striatal areas to which it projects. In keeping with the actor/critic model, the SVPE signal was detected in the substantia nigra. The SVPE was also clearly present in both the ventral striatum and the dorsal striatum. However, alongside these purely state-value-based computations we also found evidence for AVPE signals throughout the striatum. These high-resolution fMRI findings suggest that model-free aspects of reward learning in humans can be explained algorithmically with RL in terms of an actor/critic mechanism operating in parallel with a system for more direct action-value learning.

  14. High-resolution MRI using orbit surface coils for the evaluation of metastatic risk factors in 143 children with retinoblastoma. Part 2: new vs. old imaging concept

    Energy Technology Data Exchange (ETDEWEB)

    Sirin, Selma; Schlamann, Marc; Schweiger, Bernd; Goericke, Sophia L. [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Metz, Klaus A. [University Hospital Essen, Department of Pathology and Neuropathology, Essen (Germany); Bornfeld, Norbert; Holdt, Markus [University Hospital Essen, Department of Ophthalmology, Essen (Germany); Temming, Petra; Schuendeln, Michael M. [University Hospital Essen, Department of Pediatric Hematology and Oncology, Essen (Germany)

    2015-08-15

    High-resolution magnetic resonance imaging (MRI) is recommended for the evaluation of metastatic risk factors in children with retinoblastoma according to recent guidelines. The aim of this study was to compare diagnostic accuracy of a new imaging concept with two orbit surface coils to that of an old imaging concept with one orbit surface coil. One hundred forty-three patients (148 eyes, 64 girls, 79 boys) underwent high-resolution MRI on 1.5 T scanners using orbit surface coils. The old imaging concept (one orbit surface coil focusing on the (most) effected eye additionally to the standard head coil) was used in 100 patients/103 eye; the new imaging concept (two orbit surface coils (each focusing on one eye) additionally to the standard head coil) in 43 patients/45 eyes. Image analysis was performed by two neuroradiologists in consensus. Histopathology served as gold standard. Detection rate for choroidal invasion was higher for the new compared to that for the old imaging concept (sensitivity/specificity 87.5/94.6 % vs. 57.1/96.1 % for choroidal invasion and 100/97.5 % vs. 58.3/97.7 % for massive choroidal invasion, respectively). Sensitivity and specificity for the detection of postlaminar optic nerve infiltration, peribulbar fat, and scleral invasion were comparable in both imaging concepts; however positive predictive value was higher in the new imaging concept (new vs. old imaging concept: 60 vs. 31.6 % for postlaminar and deep postlaminar optic nerve infiltration, respectively, and 100 vs. 66.7 % for scleral invasion). The new imaging concept shows a trend towards improving the accuracy of detecting metastatic risk factors in children with retinoblastoma and is therefore recommended for pretherapeutic imaging and follow-up. (orig.)

  15. Detection of endogenous iron deposits in the injured mouse spinal cord through high-resolution ex vivo and in vivo MRI.

    Science.gov (United States)

    Blomster, Linda V; Cowin, Gary J; Kurniawan, Nyoman D; Ruitenberg, Marc J

    2013-02-01

    The main aim of this study was to employ high-resolution MRI to investigate the spatiotemporal development of pathological features associated with contusive spinal cord injury (SCI) in mice. Experimental mice were subjected to either sham surgery or moderate contusive SCI. A 16.4-T small-animal MR system was employed for nondestructive imaging of post-mortem, fixed spinal cord specimens at the subacute (7 days) and more chronic (28-35 days) stages post-injury. Routine histological techniques were used for subsequent investigation of the observed neuropathology at the microscopic level. The central core of the lesion appeared as a dark hypo-intense area on MR images at all time points investigated. Small focal hypo-intense spots were also observed spreading through the dorsal funiculi proximal and distal to the site of impact, an area that is known to undergo gliosis and Wallerian degeneration in response to injury. Histological examination revealed these hypo-intense spots to be high in iron content as determined by Prussian blue staining. Quantitative image analysis confirmed the increased presence of iron deposits at all post-injury time points investigated (pimaging without the use of contrast-enhancing agents, enabling the longitudinal investigation of this pathology in individual animals. Further immunohistochemical evaluation showed that intracellular iron deposits localised to macrophages/microglia, astrocytes and oligodendrocytes in the subacute phase of SCI, but predominantly to glial fibrillary acidic protein-positive, CC-1-positive astrocytes at later stages of recovery. Progressive, widespread intracellular iron accumulation is thus a normal feature of SCI in mice, and high-resolution MRI can be effectively used to detect and monitor these neuropathological changes with time. Copyright © 2012 John Wiley & Sons, Ltd.

  16. RESOLUTE PET/MRI Attenuation Correction for O-(2-18F-fluoroethyl-L-tyrosine (FET in Brain Tumor Patients with Metal Implants

    Directory of Open Access Journals (Sweden)

    Claes N. Ladefoged

    2017-08-01

    Full Text Available Aim: Positron emission tomography (PET imaging is a useful tool for assisting in correct differentiation of tumor progression from reactive changes, and the radiolabeled amino acid analog tracer O-(2-18F-fluoroethyl-L-tyrosine (FET-PET is amongst the most frequently used. The FET-PET images need to be quantitatively correct in order to be used clinically, which require accurate attenuation correction (AC in PET/MRI. The aim of this study was to evaluate the use of the subject-specific MR-derived AC method RESOLUTE in post-operative brain tumor patients.Methods: We analyzed 51 post-operative brain tumor patients (68 examinations, 200 MBq [18F]-FET investigated in a PET/MRI scanner. MR-AC maps were acquired using: (1 the Dixon water fat separation sequence, (2 the ultra short echo time (UTE sequences, (3 calculated using our new RESOLUTE methodology, and (4 a same day low-dose CT used as reference “gold standard.” For each subject and each AC method the tumor was delineated by isocontouring tracer uptake above a tumor(T-to-brain background (B activity ratio of 1.6. We measured B, tumor mean and maximal activity (TMEAN, TMAX, biological tumor volume (BTV, and calculated the clinical metrics TMEAN/B and TMAX/B.Results: When using RESOLUTE 5/68 studies did not meet our predefined acceptance criteria of TMAX/B difference to CT-AC < ±0.1 or 5%, TMEAN/B < ±0.05 or 5%, and BTV < ±2 mL or 10%. In total, 46/68 studies failed our acceptance criteria using Dixon, and 26/68 using UTE. The 95% limits of agreement for TMAX/B was for RESOLUTE (−3%; 4%, Dixon (−9%; 16%, and UTE (−7%; 10%. The absolute error when measuring BTV was 0.7 ± 1.9 mL (N.S with RESOLUTE, 5.3 ± 10 mL using Dixon, and 1.7 ± 3.7 mL using UTE. RESOLUTE performed best in the identification of the location of peak activity and in brain tumor follow-up monitoring using clinical FET PET metrics.Conclusions: Overall, we found RESOLUTE to be the AC method that most robustly

  17. Combined MR direct thrombus imaging and non-contrast magnetic resonance venography reveal the evolution of deep vein thrombosis: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Mendichovszky, I.A.; Lomas, D.J. [Addenbrooke' s Hospital, Department of Radiology, Cambridge (United Kingdom); University of Cambridge, Department of Radiology, Cambridge (United Kingdom); Priest, A.N.; Bowden, D.J.; Hunter, S.; Joubert, I.; Hilborne, S.; Graves, M.J. [Addenbrooke' s Hospital, Department of Radiology, Cambridge (United Kingdom); Baglin, T. [Addenbrooke' s Hospital, Department of Haematology, Cambridge (United Kingdom)

    2017-06-15

    Lower limb deep venous thrombosis (DVT) is a common condition with high morbidity and mortality. The aim of the study was to investigate the temporal evolution of the acute thrombus by magnetic resonance imaging (MRI) and its relationship to venous recanalization in patients with recurrent DVTs. Thirteen patients with newly diagnosed lower limb DVTs underwent MRI with non-contrast MR venography (NC-MRV) and MR direct thrombus imaging (MR-DTI), an inversion-recovery water-selective fast gradient-echo acquisition. Imaging was performed within 7 days of the acute thrombotic event, then at 3 and 6 months. By 3 months from the thrombotic event a third of the thrombi had resolved and by 6 months about half of the cases had resolved on the basis of vein recanalisation using NC-MRV. On the initial MR-DTI acute thrombus was clearly depicted by hyperintense signal, while the remaining thrombi were predominantly low signal at 3 and 6 months. Some residual thrombi contained small and fragmented persisting hyperintense areas at 3 months, clearing almost completely by 6 months. Our study suggests that synergistic venous assessment with combined NC-MRV and MR-DTI is able to distinguish acute venous thrombosis from the established (old) or evolving DVT detected by ultrasound. (orig.)

  18. A non-contrast self-navigated 3-dimensional MR technique for aortic root and vascular access route assessment in the context of transcatheter aortic valve replacement: proof of concept

    Energy Technology Data Exchange (ETDEWEB)

    Renker, Matthias [Medical University of South Carolina, Heart and Vascular Center, Charleston, SC (United States); University Hospital Giessen and Marburg, Department of Medicine I, Giessen (Germany); Varga-Szemes, Akos; Rier, Jeremy D.; Steinberg, Daniel H. [Medical University of South Carolina, Heart and Vascular Center, Charleston, SC (United States); Schoepf, U.J. [Medical University of South Carolina, Heart and Vascular Center, Charleston, SC (United States); Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Baumann, Stefan [Medical University of South Carolina, Heart and Vascular Center, Charleston, SC (United States); University of Heidelberg, 1st Department of Medicine, Faculty of Medicine Mannheim, University Medical Centre Mannheim (UMM), Mannheim (Germany); Piccini, Davide [Siemens Healthcare IM BM PI, Advanced Clinical Imaging Technology, Lausanne (Switzerland); University Hospital (CHUV) and University of Lausanne (UNIL), Department of Radiology, Lausanne (Switzerland); Zenge, Michael O.; Mueller, Edgar [Siemens AG Healthcare Sector, Erlangen (Germany); Rehwald, Wolfgang G. [Duke University Medical Center, Cardiovascular MR Center, Durham, NC (United States); Moellmann, Helge [Kerckhoff Heart and Thorax Center, Bad Nauheim (Germany); Hamm, Christian W. [University Hospital Giessen and Marburg, Department of Medicine I, Giessen (Germany); De Cecco, Carlo N. [Medical University of South Carolina, Heart and Vascular Center, Charleston, SC (United States); University of Rome ' ' Sapienza' ' -Polo Pontino, Department of Radiological Sciences, Oncology and Pathology, Latina (Italy)

    2016-04-15

    Due to the high prevalence of renal failure in transcatheter aortic valve replacement (TAVR) candidates, a non-contrast MR technique is desirable for pre-procedural planning. We sought to evaluate the feasibility of a novel, non-contrast, free-breathing, self-navigated three-dimensional (SN3D) MR sequence for imaging the aorta from its root to the iliofemoral run-off in comparison to non-contrast two-dimensional-balanced steady-state free-precession (2D-bSSFP) imaging. SN3D [field of view (FOV), 220-370 mm{sup 3}; slice thickness, 1.15 mm; repetition/echo time (TR/TE), 3.1/1.5 ms; and flip angle, 115 ] and 2D-bSSFP acquisitions (FOV, 340 mm; slice thickness, 6 mm; TR/TE, 2.3/1.1 ms; flip angle, 77 ) were performed in 10 healthy subjects (all male; mean age, 30.3 ± 4.3 yrs) using a 1.5-T MRI system. Aortic root measurements and qualitative image ratings (four-point Likert-scale) were compared. The mean effective aortic annulus diameter was similar for 2D-bSSFP and SN3D (26.7 ± 0.7 vs. 26.1 ± 0.9 mm, p = 0.23). The mean image quality of 2D-bSSFP (4; IQR 3-4) was rated slightly higher (p = 0.03) than SN3D (3; IQR 2-4). The mean total acquisition time for SN3D imaging was 12.8 ± 2.4 min. Our results suggest that a novel SN3D sequence allows rapid, free-breathing assessment of the aortic root and the aortoiliofemoral system without administration of contrast medium. (orig.)

  19. Shoulder MRI

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Shoulder Magnetic resonance imaging (MRI) of the shoulder ... limitations of MRI of the shoulder? What is MRI of the shoulder? MRI of the shoulder provides ...

  20. Knee MRI

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Knee Magnetic resonance imaging (MRI) of the knee ... of a knee MRI? What is a Knee MRI? MRI of the knee provides detailed images of ...

  1. [Examination of upper abdominal region in high spatial resolution diffusion-weighted imaging using 3-Tesla MRI].

    Science.gov (United States)

    Terada, Masaki; Matsushita, Hiroki; Oosugi, Masanori; Inoue, Kazuyasu; Yaegashi, Taku; Anma, Takeshi

    2009-03-20

    The advantage of the higher signal-to-noise ratio (SNR) of 3-Tesla magnetic resonance imaging (3-Tesla) has the possibility of contributing to the improvement of high spatial resolution without causing image deterioration. In this study, we compared SNR and the apparent diffusion coefficient (ADC) value with 3-Tesla as the condition in the diffusion-weighted image (DWI) parameter of the 1.5-Tesla magnetic resonance imaging (1.5-Tesla) and we examined the high spatial resolution images in the imaging method [respiratory-triggering (RT) method and breath free (BF) method] and artifact (motion and zebra) in the upper abdominal region of DWI at 3-Tesla. We have optimized scan parameters based on phantom and in vivo study. As a result, 3-Tesla was able to obtain about 1.5 times SNR in comparison with the 1.5-Tesla, ADC value had few differences. Moreover, the RT method was effective in correcting the influence of respiratory movement in comparison with the BF method, and image improvement by the effective acquisition of SNR and reduction of the artifact were provided. Thus, DWI of upper abdominal region was a useful sequence for the high spatial resolution in 3-Tesla.

  2. Age-related reorganization of functional networks for successful conflict resolution: a combined functional and structural MRI study.

    Science.gov (United States)

    Schulte, Tilman; Müller-Oehring, Eva M; Chanraud, Sandra; Rosenbloom, Margaret J; Pfefferbaum, Adolf; Sullivan, Edith V

    2011-11-01

    Aging has readily observable effects on the ability to resolve conflict between competing stimulus attributes that are likely related to selective structural and functional brain changes. To identify age-related differences in neural circuits subserving conflict processing, we combined structural and functional MRI and a Stroop Match-to-Sample task involving perceptual cueing and repetition to modulate resources in healthy young and older adults. In our Stroop Match-to-Sample task, older adults handled conflict by activating a frontoparietal attention system more than young adults and engaged a visuomotor network more than young adults when processing repetitive conflict and when processing conflict following valid perceptual cueing. By contrast, young adults activated frontal regions more than older adults when processing conflict with perceptual cueing. These differential activation patterns were not correlated with regional gray matter volume despite smaller volumes in older than young adults. Given comparable performance in speed and accuracy of responding between both groups, these data suggest that successful aging is associated with functional reorganization of neural systems to accommodate functionally increasing task demands on perceptual and attentional operations. Copyright © 2009 Elsevier Inc. All rights reserved.

  3. Lung morphology assessment of cystic fibrosis using MRI with ultra-short echo time at submillimeter spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Dournes, Gael [University of Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux (France); INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux (France); CHU de Bordeaux, Service d' Imagerie Thoracique et Cardiovasculaire, Service des Maladies Respiratoires, Service d' Exploration Fonctionnelle Respiratoire, Pessac (France); Centre de Recherche Cardio-thoracique de Bordeaux, INSERM, U1045, Universite de Bordeaux, Bordeaux (France); Menut, Fanny [CHU de Bordeaux, Service d' Imagerie de la Femme et de l' Enfant, Unite de Pneumologie pediatrique, Bordeaux (France); Macey, Julie; Montaudon, Michel; Berger, Patrick; Laurent, Francois [University of Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux (France); INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux (France); CHU de Bordeaux, Service d' Imagerie Thoracique et Cardiovasculaire, Service des Maladies Respiratoires, Service d' Exploration Fonctionnelle Respiratoire, Pessac (France); Fayon, Michael [University of Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux (France); INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux (France); CHU de Bordeaux, Service d' Imagerie de la Femme et de l' Enfant, Unite de Pneumologie pediatrique, Bordeaux (France); Chateil, Jean-Francois [CHU de Bordeaux, Service d' Imagerie de la Femme et de l' Enfant, Unite de Pneumologie pediatrique, Bordeaux (France); University of Bordeaux, Centre de Resonance Magnetique des Systemes Biologiques, Bordeaux (France); Salel, Marjorie; Corneloup, Olivier [University of Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux (France); CHU de Bordeaux, Service d' Imagerie Thoracique et Cardiovasculaire, Service des Maladies Respiratoires, Service d' Exploration Fonctionnelle Respiratoire, Pessac (France)

    2016-11-15

    We hypothesized that non-contrast-enhanced PETRA (pointwise encoding time reduction with radial acquisition) MR (magnetic resonance) sequencing could be an alternative to unenhanced computed tomography (CT) in assessing cystic fibrosis (CF) lung structural alterations, as well as compared agreements and concordances with those of conventional T1-weighted and T2-weighted sequences. Thirty consecutive CF patients completed both CT and MRI the same day. No contrast injection was used. Agreement in identifying structural alterations was evaluated at the segmental level using a kappa test. Intraclass correlation coefficients (ICC) and Bland-Altman analysis were used to assess concordances and reproducibility in Helbich-Bhalla disease severity scoring. Agreement between PETRA and CT was higher than that of T1- or T2-weighted sequences, notably in assessing the segmental presence of bronchiectasis (Kappa = 0.83; 0.51; 0.49, respectively). The concordance in Helbich-Bhalla scores was very good using PETRA (ICC = 0.97), independently from its magnitude (mean difference (MD) = -0.3 [-2.8; 2.2]), whereas scoring was underestimated using both conventional T1 and T2 sequences (MD = -3.6 [-7.4; 0.1]) and MD = -4.6 [-8.2; -1.0], respectively. Intra- and interobserver reproducibility were very good for all imaging modalities (ICC = 0.86-0.98). PETRA showed higher agreement in describing CF lung morphological changes than that of conventional sequences, whereas the Helbich-Bhalla scoring matched closely with that of CT. (orig.)

  4. High-resolution STIR for 3-T MRI of the posterior fossa: visualization of the lower cranial nerves and arteriovenous structures related to neurovascular compression.

    Science.gov (United States)

    Hiwatashi, Akio; Yoshiura, Takashi; Yamashita, Koji; Kamano, Hironori; Honda, Hiroshi

    2012-09-01

    Preoperative evaluation of small vessels without contrast material is sometimes difficult in patients with neurovascular compression disease. The purpose of this retrospective study was to evaluate whether 3D STIR MRI could simultaneously depict the lower cranial nerves--fifth through twelfth--and the blood vessels in the posterior fossa. The posterior fossae of 47 adults (26 women, 21 men) without gross pathologic changes were imaged with 3D STIR and turbo spin-echo heavily T2-weighted MRI sequences and with contrast-enhanced turbo field-echo MR angiography (MRA). Visualization of the cranial nerves on STIR images was graded on a 4-point scale and compared with visualization on T2-weighted images. Visualization of the arteries on STIR images was evaluated according to the segments in each artery and compared with that on MRA images. Visualization of the veins on STIR images was also compared with that on MRA images. Statistical analysis was performed with the Mann-Whitney U test. There were no significant differences between STIR and T2-weighted images with respect to visualization of the cranial nerves (p > 0.05). Identified on STIR and MRA images were 94 superior cerebellar arteries, 81 anteroinferior cerebellar arteries, and 79 posteroinferior cerebellar arteries. All veins evaluated were seen on STIR and MRA images. There were no significant differences between STIR and MRA images with respect to visualization of arteries and veins (p > 0.05). High-resolution STIR is a feasible method for simultaneous evaluation of the lower cranial nerves and the vessels in the posterior fossa without the use of contrast material.

  5. Evaluation of a 32-channel versus a 12-channel head coil for high-resolution post-contrast MRI in giant cell arteritis (GCA) at 3 T

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Philipp, E-mail: philipp.franke@uniklinik-freiburg.de [Institut für Diagnostische Radiologie, Gartenstr. 28, 79098 Freiburg (Germany); Markl, Michael, E-mail: mmarkl@northwestern.edu [Departments of Radiology and Biomedical Engineering, Northwestern University Chicago, 737 North Michigan Avenue, Suite 1600, Chicago, IL 60611 (United States); Heinzelmann, Sonja, E-mail: sonja.heinzelmann@uniklinik-freiburg.de [Department of Ophthalmology, University Hospital Freiburg, Killianstr. 5, 79106 Freiburg (Germany); Vaith, Peter, E-mail: peter.vaith@uniklinik-freiburg.de [Department of Rheumatology and Immunology, University Hospital Freiburg, Hugstetter Str. 55, 79106 Freiburg (Germany); Bürk, Jonas, E-mail: jonas.buerk@uniklinik-freiburg.de [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Str. 55, 79106 Freiburg (Germany); Langer, Mathias, E-mail: mathias.langer@uniklinik-freiburg.de [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Str. 55, 79106 Freiburg (Germany); Geiger, J., E-mail: julia.geiger@uniklinik-freiburg.de [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Str. 55, 79106 Freiburg (Germany); Department of Radiology, University Children‘s Hospital Zurich, Steinwiesstr. 75, 8032 Zurich (Switzerland)

    2014-10-15

    The aim of this study was to evaluate the diagnostic value of a 32-channel head coil for the characterization of mural inflammation patterns in the superficial cranial arteries in patients with giant cell arteritis (GCA) compared to a standard 12-channel coil at 3 T MRI. 55 patients with suspected GCA underwent high resolution T1-weighted post-contrast MRI at 3 T to detect inflammation related vessel wall enhancement using both coils. To account for different time delays between contrast agent injection and sequence acquisition, the patients were divided into two cohorts: 27 patients were examined with the 32-channel coil first and 28 patients with the 12-channel coil first. Images were evaluated by two blinded readers with regard to image quality, artifact level and arteries’ inflammation according to a standardized ranking scale; furthermore signal-to-noise ratio (SNR) measurements were performed at three locations. Identification of arteries’ inflammation was achieved with both coils with excellent inter-observer agreement (κ = 0.89 for 12-channel and κ = 0.96 for 32-channel coil). Regarding image grading, the inter-observer variability was moderate for the 12-channel (κ = 0.5) and substantial for the 32-channel coil (κ = 0.63). Significantly higher SNR and improved image quality (p < 0.01) were obtained with the 32-channel coil in either coil order. Image quality for depiction of the superficial cranial arteries was superior for the 32-channel coil. For standardized GCA diagnosis, the 12-channel coil was sufficient.

  6. Micro-finite element analysis applied to high-resolution MRI reveals improved bone mechanical competence in the distal femur of female pre-professional dancers.

    Science.gov (United States)

    Chang, G; Rajapakse, C S; Diamond, M; Honig, S; Recht, M P; Weiss, D S; Regatte, R R

    2013-04-01

    Micro-finite element analysis applied to high-resolution (0.234-mm length scale) MRI reveals greater whole and cancellous bone stiffness, but not greater cortical bone stiffness, in the distal femur of female dancers compared to controls. Greater whole bone stiffness appears to be mediated by cancellous, rather than cortical bone adaptation. The purpose of this study was to compare bone mechanical competence (stiffness) in the distal femur of female dancers compared to healthy, relatively inactive female controls. This study had institutional review board approval. We recruited nine female modern dancers (25.7±5.8 years, 1.63±0.06 m, 57.1±4.6 kg) and ten relatively inactive, healthy female controls matched for age, height, and weight (32.1±4.8 years, 1.6±0.04 m, 55.8±5.9 kg). We scanned the distal femur using a 7-T MRI scanner and a three-dimensional fast low-angle shot sequence (TR/TE=31 ms/5.1 ms, 0.234 mm×0.234 mm×1 mm, 80 slices). We applied micro-finite element analysis to 10-mm-thick volumes of interest at the distal femoral diaphysis, metaphysis, and epiphysis to compute stiffness and cross-sectional area of whole, cortical, and cancellous bone, as well as cortical thickness. We applied two-tailed t-tests and ANCOVA to compare groups. Dancers demonstrated greater whole and cancellous bone stiffness and cross-sectional area at all locations (p0.08). At all locations, the percent of intact whole bone stiffness for cortical bone alone was lower in dancers (p0.07), but adjustment for cortical bone cross-sectional area did not (pfemur compared to controls. Elevated whole bone stiffness in dancers may be mediated via cancellous, rather than cortical bone adaptation.

  7. Resonancia magnética de alta resolución en el cáncer de recto High-Resolution MRI in Rectal Cancer

    Directory of Open Access Journals (Sweden)

    Adriana Dieguez

    2010-09-01

    Full Text Available La Resonancia Magnética de alta resolución (RM AR es el mejor método para demostrar la relación del tumor rectal con el potencial margen circunferencial de resección quirúrgico. Por esta razón es considerada en la actualidad el método de elección en la estadificación local del cáncer de recto. La cirugía primaria del cáncer rectal es la escisión total del mesorrecto (ETM, cuyo plano de disección está formado por la fascia mesorrectal que envuelve la grasa del mesorrecto y al recto. Esta fascia es la que determinará el margen circunferencial de resección (MCR. Asu vez, la RM AR permite una adecuada identificación preoperatoria de importantes factores pronósticos de riesgo, mejorando la selección e indicación de la terapia para cada paciente. Esta información incluye, además del MCR, la estadificación tumoral y ganglionar, la invasión vascular extramural y la descripción de tumores de recto inferior. Todos ellos deberán ser descriptos minuciosamente en el informe, siendo parte importante de la discusión en el equipo multidisciplinario (EMD, ámbito en el cual se tomarán las decisiones que involucren al paciente con cáncer de recto. El objetivo de este trabajo es aportar la información necesaria para entender el uso de la RM AR en la identificación de los factores pronósticos de riesgo en el cáncer de recto. Se describirán los requerimientos técnicos para la realización de este estudio y el informe estandarizado, como así también los reparos anatómicos de importancia para la ETM, que como hemos dicho es la cirugía de elección en el cáncer de recto.High-resolution MRI is the best method of assessing therelation of the rectal tumor with the potential circumferentialresection margin (CRM. Therefore it is currently considered the method of choice for local staging of rectal cancer. The primary surgery of rectal cancer is total mesorectal excision (TME, which plane of dissection is formed by the mesorectal

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-03-15

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

  9. An fMRI Study of Self-Regulatory Control and Conflict Resolution in Adolescents With Bulimia Nervosa

    Science.gov (United States)

    Marsh, Rachel; Horga, Guillermo; Wang, Zhishun; Wang, Pengwei; Klahr, Kristin W.; Berner, Laura A.; Walsh, B. Timothy; Peterson, Bradley S.

    2012-01-01

    Objective The authors examined functional activity in the frontostriatal systems that mediate self-regulatory capacities and conflict resolution in adolescents with bulimia nervosa. Method Functional magnetic resonance imaging was used to compare blood-oxygen-level-dependent response in 18 female adolescents with bulimia nervosa and 18 healthy female age-matched subjects during performance on a Simon spatial incompatibility task. Bayesian analyses were used to compare the two groups on patterns of brain activation during correct responses to conflict stimuli and to explore the effects of antecedent stimulus context on group differences in self-regulation and conflict resolution. Results Adolescents with and without bulimia nervosa performed similarly on the task. During correct responses in conflict trials, frontostriatal circuits—including the right inferolateral and dorsolateral prefrontal cortices and putamen—failed to activate to the same degree in adolescents with bulimia nervosa as in healthy comparison subjects. Instead, deactivation was seen in the left inferior frontal gyrus as well as a neural system encompassing the posterior cingulate cortex and superior frontal gyrus. Group differences in cortical and striatal regions were driven by the differential responses to stimuli preceded by conflict and nonconflict stimuli, respectively. Conclusions When engaging the self-regulatory control processes necessary to resolve conflict, adolescents with bulimia nervosa displayed abnormal patterns of activation in frontostriatal and default-mode systems. Their abnormal processing of the antecedent stimulus context conditioned their brain response to conflict differently from that of healthy comparison subjects, specifically in frontal regions. It is suspected that functional disturbances in frontal portions of frontostriatal systems may release feeding behaviors from regulatory control, thereby perpetuating the conflicting desires to consume fattening foods and

  10. Does 3T Fetal MRI Improve Image Resolution of Normal Brain Structures between 20 and 24 Weeks' Gestational Age?

    Science.gov (United States)

    Priego, G; Barrowman, N J; Hurteau-Miller, J; Miller, E

    2017-08-01

    Stronger magnetic fields have the potential to improve fetal image resolution. Our objective was to detect whether there was better anatomic resolution of brain structures in fetuses imaged with a 3T magnet compared with a 1.5T magnet. Multiple cerebral and facial anatomic structures were retrospectively assessed in 28 fetal MR imaging scans with normal findings (12 at 3T and 16 at 1.5T) with a 0-3 grading score. Fetuses were assessed during the second trimesters (gestational age, 20-24 weeks). The association between the quality ratings and magnetic field strengths (1.5T versus 3T) was evaluated by a linear mixed-effects model. A quantitative assessment of the signal intensity was also performed in the different layers of the developing brain. Comparative log-ratios were calculated across the different layers of the fetal brain. There was a statistically significant interaction between location and magnetic field strength (P magnet. Similarly, statistical significance was also obtained on the quantitative assessment of the multilayer appearance of the brain; the 3T magnet had a median factor of 8.38 higher than the 1.5T magnet (95% CI, 4.73-14.82). Other anatomic structures assessed in the supratentorial compartment of the brain showed higher values on the 3T magnet with no statistical significance. Both magnets depict cerebral and facial normal anatomic structures; however, our data indicates better anatomic detail on the 3T than on the 1.5T magnet. © 2017 by American Journal of Neuroradiology.

  11. TU-F-17A-04: Respiratory Phase-Resolved 3D MRI with Isotropic High Spatial Resolution: Determination of the Average Breathing Motion Pattern for Abdominal Radiotherapy Planning

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z; Pang, J; Yang, W; Yue, Y; Tuli, R; Fraass, B; Li, D; Fan, Z [Cedars-Sinai Medical Center, Los Angeles, CA (United States)

    2014-06-15

    Purpose: To develop a retrospective 4D-MRI technique (respiratory phase-resolved 3D-MRI) for providing an accurate assessment of tumor motion secondary to respiration. Methods: A 3D projection reconstruction (PR) sequence with self-gating (SG) was developed for 4D-MRI on a 3.0T MRI scanner. The respiration-induced shift of the imaging target was recorded by SG signals acquired in the superior-inferior direction every 15 radial projections (i.e. temporal resolution 98 ms). A total of 73000 radial projections obtained in 8-min were retrospectively sorted into 10 time-domain evenly distributed respiratory phases based on the SG information. Ten 3D image sets were then reconstructed offline. The technique was validated on a motion phantom (gadolinium-doped water-filled box, frequency of 10 and 18 cycles/min) and humans (4 healthy and 2 patients with liver tumors). Imaging protocol included 8-min 4D-MRI followed by 1-min 2D-realtime (498 ms/frame) MRI as a reference. Results: The multiphase 3D image sets with isotropic high spatial resolution (1.56 mm) permits flexible image reformatting and visualization. No intra-phase motion-induced blurring was observed. Comparing to 2D-realtime, 4D-MRI yielded similar motion range (phantom: 10.46 vs. 11.27 mm; healthy subject: 25.20 vs. 17.9 mm; patient: 11.38 vs. 9.30 mm), reasonable displacement difference averaged over the 10 phases (0.74mm; 3.63mm; 1.65mm), and excellent cross-correlation (0.98; 0.96; 0.94) between the two displacement series. Conclusion: Our preliminary study has demonstrated that the 4D-MRI technique can provide high-quality respiratory phase-resolved 3D images that feature: a) isotropic high spatial resolution, b) a fixed scan time of 8 minutes, c) an accurate estimate of average motion pattern, and d) minimal intra-phase motion artifact. This approach has the potential to become a viable alternative solution to assess the impact of breathing on tumor motion and determine appropriate treatment margins

  12. Fully automatic algorithm for segmenting full human diaphragm in non-contrast CT Images

    Science.gov (United States)

    Karami, Elham; Gaede, Stewart; Lee, Ting-Yim; Samani, Abbas

    2015-03-01

    The diaphragm is a sheet of muscle which separates the thorax from the abdomen and it acts as the most important muscle of the respiratory system. As such, an accurate segmentation of the diaphragm, not only provides key information for functional analysis of the respiratory system, but also can be used for locating other abdominal organs such as the liver. However, diaphragm segmentation is extremely challenging in non-contrast CT images due to the diaphragm's similar appearance to other abdominal organs. In this paper, we present a fully automatic algorithm for diaphragm segmentation in non-contrast CT images. The method is mainly based on a priori knowledge about the human diaphragm anatomy. The diaphragm domes are in contact with the lungs and the heart while its circumference runs along the lumbar vertebrae of the spine as well as the inferior border of the ribs and sternum. As such, the diaphragm can be delineated by segmentation of these organs followed by connecting relevant parts of their outline properly. More specifically, the bottom surface of the lungs and heart, the spine borders and the ribs are delineated, leading to a set of scattered points which represent the diaphragm's geometry. Next, a B-spline filter is used to find the smoothest surface which pass through these points. This algorithm was tested on a noncontrast CT image of a lung cancer patient. The results indicate that there is an average Hausdorff distance of 2.96 mm between the automatic and manually segmented diaphragms which implies a favourable accuracy.

  13. Non-contrast thin-section helical CT of urinary tract calculi in children

    Energy Technology Data Exchange (ETDEWEB)

    Strouse, Peter J. [Section of Pediatric Radiology, University of Michigan Medical Center, Ann Arbor, MI (United States); Bates, Gregory D. [Department of Radiology, Columbus Children' s Hospital, Columbus, OH (United States); Bloom, David A. [Department of Pediatric Imaging, Children' s Hospital of Michigan, Detroit, MI (United States); Goodsitt, Mitchell M. [Department of Radiology, University of Michigan Medical Center, Ann Arbor, MI (United States)

    2002-05-01

    Background: Non-contrast thin-section helical CT has gained acceptance for the diagnosis of urinary tract calculi in adults, but experience with the technique in children is limited. Purpose: To evaluate the utility of non-contrast thin section helical CT for the diagnosis of urinary tract calculi in children. Materials and methods: Radiology databases at three pediatric institutions were searched to identify all pediatric patients evaluated by ''renal stone'' protocol CT scans (no oral or intravenous contrast, scans covering the entire urinary tract obtained in helical mode with narrow collimation (< 5 mm)). CT scans were reviewed for the primary finding of urinary tract calculi, for secondary signs of acute urinary tract obstruction and for evidence of alternative diagnoses. Medical records were reviewed to determine clinical presentation and to confirm the eventual diagnosis. Results: One hundred thirty-seven scans of 113 children (mean age: 11.2 years) were studied. Thirty-eight of 94 examinations (40%) performed on 82 children for acute pain and/or hematuria showed ureteral calculi. Alternative diagnoses were suggested by CT on 16 scans (17%). Twenty-eight scans were performed on 10 asymptomatic children with known calculus disease confirming renal stone burden on 21 scans (75%) and persistent ureteral calculi on 6 scans (21%). Upper tract calculi were demonstrated on 10 of 15 scans (67%) performed to evaluate for calculi in patients with known non-calculus genitourinary tract abnormalities. Conclusions: Non-contrast thin section helical CT is a useful method to diagnose urinary tract calculi in children. Radiation dose in this retrospective study may exceed the lowest possible radiation dose for diagnostic accuracy. Further research is needed to optimize CT imaging parameters, while maintaining diagnostic accuracy and minimizing radiation dose. (orig.)

  14. Cryogenic phased-array for high resolution magnetic resonance imaging (MRI); assessment of clinical and research applications

    Science.gov (United States)

    Ip, Flora S.

    Magnetic Resonance (MR) imaging is one of the most powerful tools in diagnostic medicine for soft tissue imaging. Image acquisition techniques and hardware receivers are very important in achieving high contrast and high resolution MR images. An aim of this dissertation is to design single and multi-element room and cryogenic temperature arrays and make assessments of their signal-to-noise ratio (SNR) and SNR gain. In this dissertation, four sets of MR receiver coils are built. They are the receiver-only cryo-coils that are not commercially available. A tuning and matching circuit is attached to each coil. The tuning and matching circuits are simple; however, each device component has to operate at a high magnetic field and cryogenic temperature environment. Remote DC bias of the varactor controls the tuning and matching outside the scanner room. Active detuning of the resonator is done by two p-i-n junction (PIN) diodes. Cooling of the receiver is done by a customized liquid nitrogen cryostat. The first application is to build a 3-Tesla 2x1 horseshoe counter-rotating current (CRC) cryogenic array to image the tibia in a human body. With significant increase in SNR, the surface coil should deliver high contrast and resolution images that can show the trabecular bone and bone marrow structure. This structural image will be used to model the mechanical strength of the bone as well as bone density and chance of fracture. The planar CRC is a unique design of this surface array. The second application is to modify the coil design to 7-Tesla to study the growth of infant rhesus monkey eyes. Fast scan MR images of the infant monkey heads are taken for monitoring shapes of their eyeballs. The monkeys are induced with shortsightedness by eye lenses, and they are scanned periodically to get images of their eyeballs. The field-of-view (FOV) of these images is about five centimeters and the area of interest is two centimeters deep from the surface. Because of these reasons

  15. The prosody of focus: non-contrastive, contrastive and verum focus in Slovenian, English and Russian

    Directory of Open Access Journals (Sweden)

    Andrej Stopar

    2017-12-01

    Full Text Available The article presents an approach to information structure that marks focused or topicalized syntactic constituents with the features [foc] and [top], and assumes that the assignment of these information structure features is reflected in prosody. The experimental study measures the fundamental frequency of various Slovenian sentences to identify the characteristic contours of the non-contrastive, contrastive, and verum focus. The findings are compared to those in studies on English and Russian. The results show that the most relevant prosodic characteristics of such structures are the pitch range, the pitch changes on the focus exponent, and the duration of the focus exponent.

  16. Diagnostic accuracy in detecting tears in the proximal biceps tendon using standard nonenhancing shoulder MRI

    Directory of Open Access Journals (Sweden)

    Dubrow SA

    2014-04-01

    Full Text Available Samuel A Dubrow,1 Jonathan J Streit,2 Yousef Shishani,2 Mark R Robbin,3 Reuben Gobezie21Department of Orthopedics, Alegent Creighton Clinic, Creighton University School of Medicine, Omaha, NE, USA; 2Department of Orthopedics, Cleveland Shoulder Institute, 3Department of Radiology, University Hospitals of Cleveland, Cleveland, OH, USABackground: There is a paucity of data in the literature evaluating the performance of noncontrast MRI in the diagnosis of partial and complete tears of the proximal portion of the long head of the biceps (LHB tendon. The objective of this study was to evaluate the accuracy of noncontrast magnetic resonance imaging (MRI compared to arthroscopy for the diagnosis of pathology involving the intra-articular portion of the LHB tendon.Methods: We conducted a retrospective review of 66 patients (mean age 57.8 years, range 43–70 years who underwent shoulder arthroscopy and evaluation of the LHB tendon after having had a noncontrast MRI of the shoulder. Biceps pathology was classified by both MRI and direct arthroscopic visualization as either normal, partial tearing, or complete rupture, and arthroscopy was considered to be the gold standard. We then determined the sensitivity, specificity, and positive- and negative-predictive values of MRI for the detection of partial and complete LHB tears.Results: MRI identified 29/66 (43.9% of patients as having a pathologic lesion of the LHB tendon (19 partial and ten complete tears while diagnostic arthroscopy identified tears in 59/66 patients (89.4%; 50 partial and 16 complete. The sensitivity and specificity of MRI for detecting partial tearing of the LHB were 27.7% and 84.2%, respectively (positive predictive value =81.2%, negative predictive value =32.0%. The sensitivity and specificity of MRI for complete tears of the LHB were 56.3% and 98.0%, respectively (positive predictive value =90.0%, negative predictive value =87.5%.Conclusion: Standard noncontrast MRI of the shoulder

  17. Automatic cerebrospinal fluid segmentation in non-contrast CT images using a 3D convolutional network

    Science.gov (United States)

    Patel, Ajay; van de Leemput, Sil C.; Prokop, Mathias; van Ginneken, Bram; Manniesing, Rashindra

    2017-03-01

    Segmentation of anatomical structures is fundamental in the development of computer aided diagnosis systems for cerebral pathologies. Manual annotations are laborious, time consuming and subject to human error and observer variability. Accurate quantification of cerebrospinal fluid (CSF) can be employed as a morphometric measure for diagnosis and patient outcome prediction. However, segmenting CSF in non-contrast CT images is complicated by low soft tissue contrast and image noise. In this paper we propose a state-of-the-art method using a multi-scale three-dimensional (3D) fully convolutional neural network (CNN) to automatically segment all CSF within the cranial cavity. The method is trained on a small dataset comprised of four manually annotated cerebral CT images. Quantitative evaluation of a separate test dataset of four images shows a mean Dice similarity coefficient of 0.87 +/- 0.01 and mean absolute volume difference of 4.77 +/- 2.70 %. The average prediction time was 68 seconds. Our method allows for fast and fully automated 3D segmentation of cerebral CSF in non-contrast CT, and shows promising results despite a limited amount of training data.

  18. Residual analysis of the water resonance signal in breast lesions imaged with high spectral and spatial resolution (HiSS) MRI: A pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, William A., E-mail: willw00@uchicago.edu; Medved, Milica; Karczmar, Gregory S.; Giger, Maryellen L. [Department of Radiology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637 (United States)

    2014-01-15

    Purpose: High spectral and spatial resolution magnetic resonance imaging (HiSS MRI) yields information on the local environment of suspicious lesions. Previous work has demonstrated the advantages of HiSS (complete fat-suppression, improved image contrast, no required contrast agent, etc.), leading to initial investigations of water resonance lineshape for the purpose of breast lesion classification. The purpose of this study is to investigate a quantitative imaging biomarker, which characterizes non-Lorentzian components of the water resonance in HiSS MRI datasets, for computer-aided diagnosis (CADx). Methods: The inhomogeneous broadening and non-Lorentzian or “off-peak” components seen in the water resonance of proton spectra of breast HiSS images are analyzed by subtracting a Lorentzian fit from the water peak spectra and evaluating the difference spectrum or “residual.” The maxima of these residuals (referred to hereafter as “off-peak components”) tend to be larger in magnitude in malignant lesions, indicating increased broadening in malignant lesions. The authors considered only those voxels with the highest magnitude off-peak components in each lesion, with the number of selected voxels dependent on lesion size. Our voxel-based method compared the magnitudes and frequencies of off-peak components of all voxels from all lesions in a database that included 15 malignant and 8 benign lesions (yielding ∼3900 voxels) based on the lesions’ biopsy-confirmed diagnosis. Lesion classification was accomplished by comparing the average off-peak component magnitudes and frequencies in malignant and benign lesions. The area under the ROC curve (AUC) was used as a figure of merit for both the voxel-based and lesion-based methods. Results: In the voxel-based task of distinguishing voxels from malignant and benign lesions, off-peak magnitude yielded an AUC of 0.88 (95% confidence interval [0.84, 0.91]). In the lesion-based task of distinguishing malignant and

  19. [Evaluation of the right internal iliac artery which is anastomosed to transplant renal artery using non-contrast enhanced MR angiography with electrocardiography-gated and 3D True SSFP time-spatial labeling inversion pulse sequence].

    Science.gov (United States)

    Yoshida, Ayako; Shiratori, Yoko; Suzuki, Makoto; Ozasa, Masaya; Takeyama, Mamoru; Eshima, Mitsuhiro; Shinohara, Maiko; Yamamoto, Takao; Tajima, Tsuyoshi

    2015-05-01

    To evaluate whether electrocardiography-gated is useful in non-contrast-enhanced MRA with time-spatial labeling inversion pulse (Time-SLIP) in renal transplantation patients compared with respiration-triggered free-breathing. Simulation-based analyses of black blood time interval (BBTI) values for spatial selective inversion-recovery pulse and electrocardiography rates were performed, and confirmed on human subjects using a three-dimensional (3D) coherent steady-state free precession (SSFP) sequence on a 1.5 tesla Toshiba MRI scanner. Signal acquisition interval and BBTI values in which signal of a water tissue becomes the null point showed a strong correlation, and successfully suppressed signals from the background and provided better contrast between the arteries and the background. Because electrocardiography-gated non-contrast MRA does not depend on the respiration interval, providing a contrast stable, it was suggested to be an effective screening tool for evaluation of pelvic arteries.

  20. Non-contrast enhanced navigator-gated balanced steady state free precession magnetic resonance angiography as a preferred magnetic resonance technique for assessment of the thoracic aorta.

    Science.gov (United States)

    van Kesteren, F; Elattar, M A; van Lienden, K P; Baan, J; Marquering, H A; Planken, R N

    2017-08-01

    To compare the objective and subjective image quality of non-contrast three-dimensional (3D) navigator-gated balanced steady state free precession magnetic resonance angiography (NC-MRA) and contrast-enhanced magnetic resonance angiography (CE-MRA) along the entire thoracic aorta. Fifty consecutive patients with thoracic aortic disease underwent NC-MRA and CE-MRA using a 1.5 T MRI system. Vessel sharpness was assessed using signal intensity profiles at five predefined levels of the thoracic aorta. Two readers scored subjective quality. Manual diameter measurements of both readers were used for calculation of interobserver variation. NC-MRA resulted in significantly sharper delineation of the aortic root, ascending aorta, and distal descending aorta compared to CE-MRA. Sharpness was comparable at the level of the arch and proximal descending aorta. NC-MRA resulted in significantly better subjective image quality. Interobserver agreement for diameter measurements was excellent for both techniques. NC-MRA resulted in superior image quality for assessment of the thoracic aorta and in better vessel sharpness for assessment of the aortic root and ascending aorta, when compared to CE-MRA. NC-MRA can be considered the MRA technique of choice for the assessment of the thoracic aorta diameters in clinical practice. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  1. A systematic evaluation of intraoperative white matter tract shift in pediatric epilepsy surgery using high-field MRI and probabilistic high angular resolution diffusion imaging tractography.

    Science.gov (United States)

    Yang, Joseph Yuan-Mou; Beare, Richard; Seal, Marc L; Harvey, A Simon; Anderson, Vicki A; Maixner, Wirginia J

    2017-05-01

    OBJECTIVE Characterization of intraoperative white matter tract (WMT) shift has the potential to compensate for neuronavigation inaccuracies using preoperative brain imaging. This study aimed to quantify and characterize intraoperative WMT shift from the global hemispheric to the regional tract-based scale and to investigate the impact of intraoperative factors (IOFs). METHODS High angular resolution diffusion imaging (HARDI) diffusion-weighted data were acquired over 5 consecutive perioperative time points (MR1 to MR5) in 16 epilepsy patients (8 male; mean age 9.8 years, range 3.8-15.8 years) using diagnostic and intraoperative 3-T MRI scanners. MR1 was the preoperative planning scan. MR2 was the first intraoperative scan acquired with the patient's head fixed in the surgical position. MR3 was the second intraoperative scan acquired following craniotomy and durotomy, prior to lesion resection. MR4 was the last intraoperative scan acquired following lesion resection, prior to wound closure. MR5 was a postoperative scan acquired at the 3-month follow-up visit. Ten association WMT/WMT segments and 1 projection WMT were generated via a probabilistic tractography algorithm from each MRI scan. Image registration was performed through pairwise MRI alignments using the skull segmentation. The MR1 and MR2 pairing represented the first surgical stage. The MR2 and MR3 pairing represented the second surgical stage. The MR3 and MR4 (or MR5) pairing represented the third surgical stage. The WMT shift was quantified by measuring displacements between a pair of WMT centerlines. Linear mixed-effects regression analyses were carried out for 6 IOFs: head rotation, craniotomy size, durotomy size, resected lesion volume, presence of brain edema, and CSF loss via ventricular penetration. RESULTS The average WMT shift in the operative hemisphere was 2.37 mm (range 1.92-3.03 mm) during the first surgical stage, 2.19 mm (range 1.90-3.65 mm) during the second surgical stage, and 2.92 mm

  2. Simultaneous Non-contrast Angiography and intraPlaque hemorrhage (SNaP) imaging for carotid atherosclerotic disease evaluation

    NARCIS (Netherlands)

    Wang, J.; Boernert, P.; Zhao, H.; Hippe, D.; Xihai Zhao; Balu, N.; Ferguson, M.S.; Hatsukami, T.S.; Xu, J.; Yuan, C.; Kerwin, W.S.

    2012-01-01

    A Simultaneous Non-contrast Angiography and intraPlaque hemorrhage (SNAP) MR imaging technique was proposed to detect both luminal stenosis and hemorrhage in atherosclerosis patients in a single scan. 13patients with diagnosed carotid atherosclerotic plaque were recruited after informed consent. All

  3. Mapping primary gyrogenesis during fetal development in primate brains: high-resolution in utero structural MRI study of fetal brain development in pregnant baboons

    Directory of Open Access Journals (Sweden)

    Peter Kochunov

    2010-05-01

    Full Text Available The global and regional changes in the fetal cerebral cortex in primates were mapped during primary gyrification (PG; weeks 17-25 of 26 weeks total gestation. Studying pregnant baboons using high-resolution MRI in utero, measurements included cerebral volume, cortical surface area, gyrification index and length and depth of ten primary cortical sulci. Seven normally developing fetuses were imaged in two animals longitudinally and sequentially. We compared these results to those on PG that from the ferret studies and analyzed them in the context of our recent studies of phylogenetics of cerebral gyrification. We observed that in both primates and non-primates, the cerebrum undergoes a very rapid transformation into the gyrencephalic state, subsequently accompanied by an accelerated growth in brain volume and cortical surface area. However, PG trends in baboons exhibited some critical differences from those observed in ferrets. For example, in baboons, the growth along the long (length axis of cortical sulci was unrelated to the growth along the short (depth axis and far outpaced it. Additionally, the correlation between the rate of growth along the short sulcal axis and heritability of sulcal depth was negative and approached significance (r=-0.60;p<.10, while the same trend for long axis was positive and not significant (p=0.3;p=0.40. These findings, in an animal that shares a highly orchestrated pattern of PG with humans, suggest that ontogenic processes that influence changes in sulcal length and depth are diverse and possibly driven by different factors in primates than in non-primates.

  4. Cetacean brain evolution: Dwarf sperm whale (Kogia sima) and common dolphin (Delphinus delphis) - An investigation with high-resolution 3D MRI.

    Science.gov (United States)

    Oelschläger, H H A; Ridgway, S H; Knauth, M

    2010-01-01

    This study compares a whole brain of the dwarf sperm whale (Kogia sima) with that of a common dolphin (Delphinus delphis) using high-resolution magnetic resonance imaging (MRI). The Kogia brain was scanned with a Siemens Trio Magnetic Resonance scanner in the three main planes. As in the common dolphin and other marine odontocetes, the brain of the dwarf sperm whale is large, with the telencephalic hemispheres remarkably dominating the brain stem. The neocortex is voluminous and the cortical grey matter thin but expansive and densely convoluted. The corpus callosum is thin and the anterior commissure hard to detect whereas the posterior commissure is well-developed. There is consistency as to the lack of telencephalic structures (olfactory bulb and peduncle, olfactory ventricular recess) and neither an occipital lobe of the telencephalic hemisphere nor the posterior horn of the lateral ventricle are present. A pineal organ could not be detected in Kogia. Both species show a tiny hippocampus and thin fornix and the mammillary body is very small whereas other structures of the limbic system are well-developed. The brain stem is thick and underlies a large cerebellum, both of which, however, are smaller in Kogia. The vestibular system is markedly reduced with the exception of the lateral (Deiters') nucleus. The visual system, although well-developed in both species, is exceeded by the impressive absolute and relative size of the auditory system. The brainstem and cerebellum comprise a series of structures (elliptic nucleus, medial accessory inferior olive, paraflocculus and posterior interpositus nucleus) showing characteristic odontocete dimensions and size correlations. All these structures seem to serve the auditory system with respect to echolocation, communication, and navigation. 2010 S. Karger AG, Basel.

  5. Advanced Noncontrast Magnetic Resonance Angiography of the Thoracic and Peripheral Arteries

    Science.gov (United States)

    Lindley, Marc Daniel

    The gold standard for evaluation of arterial disease using MR continues to be contrast-enhanced MR angiography (MRA) with gadolinium-based contrast agents (Gd-MRA). There has been a recent resurgence in interest in methods that do not rely on gadolinium for enhancement of blood vessels due to associations Gd-MRA has with nephrogenic systemic fibrosis (NSF) in patients with impaired renal function. The risk due to NSF has been shown to be minimized when selecting the appropriate contrast type and dose. Even though the risk of NSF has been shown to be minimized, demand for noncontrast MRA has continued to rise to reduce examination cost, and improve patient comfort and ability to repeat scans. Several methods have been proposed and used to perform angiography of the aorta and peripheral arteries without the use of gadolinium. These techniques have had limitations in transmit radiofrequency field (B1+) inhomogeneities, acquisition time, and specific hardware requirements, which have stunted the utility of noncontrast enhanced MRA. In this work feasibility of noncontrast (NC) MRA at 3T of the femoral arteries using dielectric padding, and using 3D radial stack of stars and compressed sensing to accelerate acquisitions in the abdomen and thorax were tested. Imaging was performed on 13 subjects in the pelvis and thighs using high permittivity padding, and 11 in the abdomen and 19 in the thorax using 3D radial stack of stars with tiny golden angle using gold standards or previously published techniques. Qualitative scores for each study were determined by radiologists who were blinded to acquisition type. Vessel conspicuity in the thigh and pelvis showed significant increase when high permittivity padding was used in the acquisition. No significant difference in image quality was observed in the abdomen and thorax when using undersampling, except for the descending aorta in thoracic imaging. All image quality scores were determined to be of diagnostic quality. In this

  6. A strategy to optimize radiation exposure for non-contrast head CT: comparison with the Japanese diagnostic reference levels.

    Science.gov (United States)

    Kumamaru, Kanako K; Kogure, Yosuke; Suzuki, Michimasa; Hori, Masaaki; Nakanishi, Atsushi; Kamagata, Koji; Hagiwara, Akifumi; Andica, Christina; Ri, Keiken; Houshido, Naoyoshi; Aoki, Shigeki

    2016-06-01

    To describe how we performed a protocol review, analyzed data, identified opportunities to reduce radiation exposure, and then implemented a new imaging protocol for non-contrast adult head CT at our institution with reduced radiation exposure, using the Japanese diagnostic reference levels (DRLs) as the reference. After analyzing the CT dose index (CTDIvol) and dose length product (DLP) in all non-contrast adult head CT examinations performed during a 3-month period (September to November 2015) in order to identify a specific protocol that contributed to the above-DRL-level radiation exposure observed for non-contrast adult head CT at our institution, phantom studies with objective and subjective image quality analyses were performed to develop a new imaging protocol. After implementing the new protocol, its feasibility was evaluated in terms of radiation exposure, prevalence of significant disease detection, and subjective image quality. The review of 2040 examinations revealed that a helical protocol (CTDIvol = 93.4 mGy) with one of four CT scanners mainly contributed to the above-DRL-level radiation exposure (mean DLP at this scanner = 1401.2 mGy cm) in non-contrast adult head CT at our institution. To replace this protocol, the phantom study identified a wide-volume scan using 120 kVp, 350 mAs, a 4-cm detector, a slice thickness of 5 mm, and a CTDIvol of 69.8 mGy as a new protocol that yielded comparable image quality to the existing protocol. After the implementation of the new protocol, the overall mean DLP reduced to 1365 mGy cm without any apparent degradation of image quality. No significant decrease in the prevalence of significant findings after protocol revision was noted. We report the successful implementation of a new protocol with reduced radiation exposure for non-contrast head CT examinations.

  7. Computer-Aided Detection of Exophytic Renal Lesions on Non-Contrast CT Images

    Science.gov (United States)

    Liu, Jianfei; Wang, Shijun; Linguraru, Marius George; Yao, Jianhua; Summers, Ronald M.

    2014-01-01

    Renal lesions are important extracolonic findings on computed tomographic colonography (CTC). They are difficult to detect on non-contrast CTC images due to low image contrast with surrounding objects. In this paper, we developed a novel computer-aided diagnosis system to detect a subset of renal lesions, exophytic lesions, by 1) exploiting efficient belief propagation to segment kidneys, 2) establishing an intrinsic manifold diffusion on kidney surface, 3) searching for potential lesion-caused protrusions with local maximum diffusion response, and 4) exploring novel shape descriptors, including multi-scale diffusion response, with machine learning to classify exophytic renal lesions. Experimental results on the validation dataset with 167 patients revealed that manifold diffusion significantly outperformed conventional shape features (p computer-aided diagnosis of renal lesions. PMID:25189363

  8. Detection of Early Ischemic Changes in Noncontrast CT Head Improved with "Stroke Windows".

    Science.gov (United States)

    Mainali, Shraddha; Wahba, Mervat; Elijovich, Lucas

    2014-01-01

    Introduction. Noncontrast head CT (NCCT) is the standard radiologic test for patients presenting with acute stroke. Early ischemic changes (EIC) are often overlooked on initial NCCT. We determine the sensitivity and specificity of improved EIC detection by a standardized method of image evaluation (Stroke Windows). Methods. We performed a retrospective chart review to identify patients with acute ischemic stroke who had NCCT at presentation. EIC was defined by the presence of hyperdense MCA/basilar artery sign; sulcal effacement; basal ganglia/subcortical hypodensity; and loss of cortical gray-white differentiation. NCCT was reviewed with standard window settings and with specialized Stroke Windows. Results. Fifty patients (42% females, 58% males) with a mean NIHSS of 13.4 were identified. EIC was detected in 9 patients with standard windows, while EIC was detected using Stroke Windows in 35 patients (18% versus 70%; P Windows (14% and 36%; P Windows (6% and 46%; P Windows significantly improved detection of EIC.

  9. Myocardial tissue characterization using magnetic resonance noncontrast t1 mapping in hypertrophic and dilated cardiomyopathy.

    Science.gov (United States)

    Dass, Sairia; Suttie, Joseph J; Piechnik, Stefan K; Ferreira, Vanessa M; Holloway, Cameron J; Banerjee, Rajarshi; Mahmod, Masliza; Cochlin, Lowri; Karamitsos, Theodoros D; Robson, Matthew D; Watkins, Hugh; Neubauer, Stefan

    2012-11-01

    Noncontrast magnetic resonance T1 mapping reflects a composite of both intra- and extracellular signal. We hypothesized that noncontrast T1 mapping can characterize the myocardium beyond that achieved by the well-established late gadolinium enhancement (LGE) technique (which detects focal fibrosis) in both hypertrophic (HCM) and dilated (DCM) cardiomyopathy, by detecting both diffuse and focal fibrosis. Subjects underwent Cardiovascular Magnetic Resonance imaging at 3T (28 HCM, 18 DCM, and 12 normals). Matching short-axis slices were acquired for cine, T1 mapping, and LGE imaging (0.1 mmol/kg). Circumferential strain was measured in the midventricular slice, and (31)P magnetic resonance spectroscopy was acquired for the septum of the midventricular slice. Mean T1 relaxation time was increased in HCM and DCM (HCM 1209±28 ms, DCM 1225±42 ms, normal 1178±13 ms, PT1 and LGE (r=0.32, PT1 values were higher in segments with LGE than in those without (HCM with LGE 1228±41 ms versus no LGE 1192±79 ms, PT1 values were significantly higher than normal (PT1 values correlated with disease severity, being increased as wall thickness increased in HCM; conversely, in DCM, T1 values were highest in the thinnest myocardial segments. T1 values also correlated significantly with circumferential strain (r=0.42, PT1 values and phosphocreatine/adenosine triphosphate ratios (r=-0.59, PT1 mapping detects underlying disease processes beyond those assessed by LGE in relatively low-risk individuals.

  10. Chest MRI

    Science.gov (United States)

    Nuclear magnetic resonance - chest; Magnetic resonance imaging - chest; NMR - chest; MRI of the thorax; Thoracic MRI ... healthy enough to filter the contrast. During the MRI, the person who operates the machine will watch ...

  11. Non-contrast CT at comparable dose to an abdominal radiograph in patients with acute renal colic; impact of iterative reconstruction on image quality and diagnostic performance.

    LENUS (Irish Health Repository)

    McLaughlin, P D

    2014-04-01

    The aim was to assess the performance of low-dose non-contrast CT of the urinary tract (LD-CT) acquired at radiation exposures close to that of abdominal radiography using adaptive statistical iterative reconstruction (ASiR).

  12. Simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) imaging: Comparison with contrast-enhanced MR angiography for measuring carotid stenosis.

    Science.gov (United States)

    Shu, Hongge; Sun, Jie; Hatsukami, Thomas S; Balu, Niranjan; Hippe, Daniel S; Liu, Haining; Kohler, Ted R; Zhu, Wenzhen; Yuan, Chun

    2017-10-01

    To evaluate in a proof-of-concept study the feasibility of Simultaneous Noncontrast Angiography and intraPlaque hemorrhage (SNAP) imaging as a clinical magnetic resonance angiography (MRA) technique for measuring carotid stenosis. There is a growing interest in detecting intraplaque hemorrhage (IPH) during the clinical management of carotid disease, yet luminal stenosis has remained indispensable during clinical decision-making. SNAP imaging has been proposed as a novel IPH imaging technique that provides carotid MRA with no added scan time. Flowing blood shows negative signal on SNAP because of phase-sensitive inversion recovery. In all, 58 asymptomatic subjects with 16-79% stenosis on ultrasound were scanned at 3T by SNAP with 0.8 mm isotropic resolution and 16 cm longitudinal coverage. Two readers measured luminal stenosis of bilateral carotid arteries (n = 116) on minimum intensity projections of SNAP using the NASCET criteria. In the subset (48 arteries) with contrast-enhanced (CE) MRA available for comparison, luminal stenosis was also measured on maximum intensity projections of CE-MRA. Intraclass correlation coefficients (ICCs) with 95% confidence intervals were 0.94 (0.90-0.96) and 0.93 (0.88-0.96) for intra- and interreader agreement on stenosis measurements, respectively. Corresponding kappas for grading stenosis (0-29%, 30-69%, 70-99%, and 100%) were 0.79 (0.67-0.89) and 0.80 (0.68-0.90). Agreement between SNAP and CE-MRA was high (ICC: 0.95 [0.90-0.98]; kappa: 0.82 [0.71-0.93]). As a dedicated IPH-imaging sequence, SNAP also provided carotid stenosis measurement that showed high intra- and interreader consistency and excellent agreement with CE-MRA. Further comparisons with digital subtraction angiography and other noninvasive techniques are warranted. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1045-1052. © 2017 International Society for Magnetic Resonance in Medicine.

  13. Pseudotumours in chronic kidney disease: Can diffusion-weighted MRI rule out malignancy

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, Ankur, E-mail: ankurgoyalaiims@gmail.com [Department of Radiodiagnosis, All India Institute of Medical Sciences (A.I.I.M.S.), New Delhi (India); Sharma, Raju, E-mail: raju152@yahoo.com [Department of Radiodiagnosis, All India Institute of Medical Sciences (A.I.I.M.S.), New Delhi (India); Bhalla, Ashu S., E-mail: ashubhalla1@yahoo.com [Department of Radiodiagnosis, All India Institute of Medical Sciences (A.I.I.M.S.), New Delhi (India); Gamanagatti, Shivanand, E-mail: shiv223@rediffmail.com [Department of Radiodiagnosis, All India Institute of Medical Sciences (A.I.I.M.S.), New Delhi (India); Seth, Amlesh, E-mail: amlesh.seth@gmail.com [Department of Urology, All India Institute of Medical Sciences (A.I.I.M.S.), New Delhi (India)

    2013-11-01

    Highlights: •Conventional non-contrast MRI is unable to distinguish CKD pseudotumors from RCCs. •Pseudotumours in a background of CKD do not show restricted diffusion. •CKD pseudotumours demonstrate high ADC values whereas RCCs show restricted diffusion. •DW-MRI is reliable in ruling out malignancy incase of pseudotumours found in chronic kidney disease. •DW-MRI may obviate contrast administration and/or tissue sampling in renal pseudotumours and prevent inadvertent surgeries. -- Abstract: Objectives: To evaluate whether diffusion-weighted MRI (DW-MRI) can distinguish pseudotumours in chronic kidney disease (CKD pseudotumours) from renal-cell-carcinomas (RCCs) (with or without CKD) and whether it offers additional benefit over conventional MRI. Methods: One-hundred patients underwent MDCT, MRI and DW-MRI (at b-values of 0 and 500 s/mm{sup 2}) for evaluation of focal renal lesions. Of these, 20 patients with 40 CKD pseudotumours and 36 patients with 40 RCCs were retrospectively analyzed. T1-weighted, T2-weighted, diffusion-weighted images were evaluated, apparent-diffusion-coefficient (ADC) values were compared and receiver-operating-characteristic (ROC) curves were drawn to establish cut-off ADC-values. Results: 92.5% of CKD pseudotumours remained indeterminate after conventional MRI. On DW-MRI, none of them showed restricted diffusion and thus malignancy could be ruled out in 100% of the lesions. In contrast, all the solid RCCs showed diffusion restriction. Mean ADC-value for CKD pseudotumours was significantly higher than RCCs and surrounding diseased parenchyma [2.50 vs 1.56 (×10{sup −3} mm{sup 2}/s) (P < 0.0001) and 2.05 (×10{sup −3} mm{sup 2}/s) (P = 0.0001) respectively]. ROC analysis for differentiating CKD pseudotumours and RCC yielded high sensitivity (91.7%) and specificity (100%) for cut-off ADC-value of 2.04 (×10{sup −3} mm{sup 2}/s). Conclusions: CKD pseudotumors usually remain indeterminate on conventional non-contrast MRI. DW-MRI

  14. In Vivo Validation of Simultaneous Non-Contrast Angiography and intraPlaque Hemorrhage (SNAP) Magnetic Resonance Angiography: An Intracranial Artery Study.

    Science.gov (United States)

    Wang, Jinnan; Guan, Maobin; Yamada, Kiyofumi; Hippe, Daniel S; Kerwin, William S; Yuan, Chun; Börnert, Peter; Zhao, Xihai

    2016-01-01

    Simultaneous Non-contrast Angiography and intraPlaque hemorrhage (SNAP) technique was recently proposed for joint MRA and intraplaque hemorrhage (IPH) imaging. The purpose of this study is to validate SNAP's MRA performance in patients with suspected intracranial artery disease. SNAP and time-of-flight (TOF) techniques with matched field of view and resolution were applied on 15 patients with suspected intracranial artery disease. Both techniques were evaluated based on their detection of luminal stenosis of bilateral middle cerebral arteries (MCA) and the delineation of smallest visible branches (SVB) of the MCA. Statistical analysis was conducted on the artery level. The SNAP MRA was found to provide similar stenosis detection performance when compared with TOF (Cohen's κ 0.79; 95% Confidence Interval: 0.56-0.99). For the SVB comparison, SNAP was found to provide significantly better small artery delineation than TOF (p = 0.017). Inter-reader reproducibility for both measurements on SNAP was over 0.7. SNAP also detected IPH lesions on 13% of the patients. The SNAP technique's MRA performance was optimized and compared against TOF for intracranial artery atherosclerosis imaging and was found to provide comparable stenosis detection accuracy. Along with its IPH detection capability, SNAP holds the potential to become a first-line screening tool for high risk intracranial atherosclerosis disease evaluation.

  15. Utility of combined high-resolution bone SPECT and MRI for the identification of rheumatoid arthritis patients with high-risk for erosive progression

    Energy Technology Data Exchange (ETDEWEB)

    Buchbender, Christian, E-mail: christian.buchbender@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225 Dusseldorf (Germany); Sewerin, Philipp, E-mail: philipp.sewerin@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Rheumatology, Moorenstr. 5, D-40225 Dusseldorf (Germany); Mattes-György, Katalin, E-mail: katalin.mattes@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Nuclear Medicine, Moorenstr. 5, D-40225 Dusseldorf (Germany); Miese, Falk, E-mail: falk.miese@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225 Dusseldorf (Germany); Wittsack, Hans-Joerg, E-mail: hans-joerg.wittsack@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225 Dusseldorf (Germany); Specker, Christof, E-mail: c.specker@kliniken-essen-sued.de [Department of Rheumatology and Clinical Immunology, Kliniken Essen-Sud, Propsteistrasse 2, D-45239 Essen (Germany); Antoch, Gerald, E-mail: antoch@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225 Dusseldorf (Germany); Müller, Hans-Wilhelm, E-mail: HansW.Mueller@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Nuclear Medicine, Moorenstr. 5, D-40225 Dusseldorf (Germany); Schneider, Matthias, E-mail: matthias.schneider@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Rheumatology, Moorenstr. 5, D-40225 Dusseldorf (Germany); Scherer, Axel, E-mail: scherer@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstr. 5, D-40225 Dusseldorf (Germany); Ostendorf, Benedikt, E-mail: ostendorf@med.uni-duesseldorf.de [Univ Dusseldorf, Medical Faculty, Department of Rheumatology, Moorenstr. 5, D-40225 Dusseldorf (Germany)

    2013-02-15

    Objectives: To evaluate the utility of sequentially acquired, post hoc fused, magnetic resonance imaging (MRI) and multi-pinhole single photon emission computed tomography (MPH-SPECT) with technetium-99m-labeled disphosphonates (Tc99m-DPD) for the identification of finger joints with later erosive progression in early rheumatoid arthritis (ERA) patients. Methods: Ten consecutive ERA patients prospectively underwent MPH-SPECT and MRI of metacarpophalangeal (MCP) joints prior to and after 6 months methotrexate therapy. Tc99m-DPD uptake was measured at proximal and distal MCP sites using regional analysis. The course of joint pathologies was scored according to the Rheumatoid Arthritis MRI Score (RAMRIS) criteria. Results: The frequency of increased Tc99m-DPD uptake, synovitis and bone marrow edemadecreased under MTX therapy; but the number of bone erosions increased. Joints with progressive and new erosions on follow-up had a higher baseline Tc99m-DPD uptake (2.64 ± 1.23 vs. 1.43 ± 0.91) (p = 0.02). Conclusions: Joints with erosive progression are characterized by an early increased Tc99m-DPD uptake, even in absence of MRI bone pathologies. Tc99m-DPD MPH-SPECT might thus be of additional value to morphological MRI for the identification of RA patients with a high risk for erosive progression.

  16. Effect of TIPS placement on portal and splanchnic arterial blood flow in 4-dimensional flow MRI

    Energy Technology Data Exchange (ETDEWEB)

    Stankovic, Zoran [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Roessle, Martin; Schultheiss, Michael [University Medical Center Freiburg, Department of Gastroenterology, Freiburg (Germany); Euringer, Wulf; Langer, Mathias [University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Salem, Riad; Barker, Alex; Carr, James; Collins, Jeremy D. [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States)

    2015-09-15

    To assess changes in portal and splanchnic arterial haemodynamics in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS) using four-dimensional (4D) flow MRI, a non-invasive, non-contrast imaging technique. Eleven patients undergoing TIPS implantation were enrolled. K-t GRAPPA accelerated non-contrast 4D flow MRI of the liver vasculature was applied with acceleration factor R = 5 at 3Tesla. Flow analysis included three-dimensional (3D) blood flow visualization using time-resolved 3D particle traces and semi-quantitative flow pattern grading. Quantitative evaluation entailed peak velocities and net flows throughout the arterial and portal venous (PV) systems. MRI measurements were taken within 24 h before and 4 weeks after TIPS placement. Three-dimensional flow visualization with 4D flow MRI revealed good image quality with minor limitations in PV flow. Quantitative analysis revealed a significant increase in PV flow (562 ± 373 ml/min before vs. 1831 ± 965 ml/min after TIPS), in the hepatic artery (176 ± 132 ml/min vs. 354 ± 140 ml/min) and combined flow in splenic and superior mesenteric arteries (770 ml/min vs. 1064 ml/min). Shunt-flow assessment demonstrated stenoses in two patients confirmed and treated at TIPS revision. Four-dimensional flow MRI might have the potential to give new information about the effect of TIPS placement on hepatic perfusion. It may explain some unexpected findings in clinical observation studies. (orig.)

  17. The accuracy of noncontrast spiral computerized tomography in detecting lucent renal stones: A case report and literature review

    OpenAIRE

    Adwan, Ayman; Binsaleh, Saleh

    2015-01-01

    Renal stones are one of the most common diseases in the urology field that are easily diagnosed by one of the standard imaging techniques. Noncontrast spiral computerized tomography (CT) can detect up to 95% of the renal, ureteric and bladder stones, especially those with calcium composition, and considered nowadays one of the most accurate methods for detecting undetectable stones by other modalities. We report a case of a 60-year-old female who presented with colicky right flank pain due to...

  18. Quantification of peri-aortic root fat from non-contrast ECG-gated cardiac computed tomography

    Directory of Open Access Journals (Sweden)

    Chun-Ho Yun

    2015-12-01

    PARF was measured using images of gated non-contrast cardiac computed tomography (CT and a dedicated workstation (Aquarius 3D Workstation, TeraRecon, San Mateo, CA, USA. The stratified analyses were performed in order to assess the association between carotid morphology, remodeling and PARF by tertile. For further analyses and discussion, please see “The Association among Peri-Aortic Root Adipose Tissue, Metabolic derangements and Burden of Atherosclerosis in Asymptomatic Population” by Yun et al. (2015 [1].

  19. Brain MRI changes in chronic liver disease

    Energy Technology Data Exchange (ETDEWEB)

    Skehan, S. [Department of Diagnostic Imaging, St. Vincent`s Hospital, Elm Park, Dublin 4 (Ireland); Norris, S. [Liver Unit, St. Vincent`s Hospital, Elm Park, Dublin 4 (Ireland); Hegarty, J. [Liver Unit, St. Vincent`s Hospital, Elm Park, Dublin 4 (Ireland); Owens, A. [Department of Diagnostic Imaging, St. Vincent`s Hospital, Elm Park, Dublin 4 (Ireland); MacErlaine, D. [Department of Diagnostic Imaging, St. Vincent`s Hospital, Elm Park, Dublin 4 (Ireland)

    1997-08-01

    Cirrhotic patients are known to have abnormally high signal principally in the globus pallidus on non-contrast T1-weighted MRI. The purpose of this study was to relate MR changes to clinical and pathological features of chronic liver disease. We confirmed abnormally high signal in the globus pallidus on T1-weighted images in 25 of 28 patients with chronic liver disease, showing that it also occurs in patients who have not yet progressed to cirrhosis. Changes were seen in patients both with and without clinical portosystemic shunting. This abnormality is not responsible for hepatic encephalopathy. Cholestatic disease was more likely to produce marked changes than non-cholestatic disease. No statistically significant correlation was demonstrated between the severity of liver disease and the degree of MR abnormality. However, marked improvement in MR appearances was seen after successful liver transplantation. (orig.). With 3 figs., 4 tabs.

  20. Accuracy of non-contrast PMCT for determining cause of death.

    Science.gov (United States)

    Ampanozi, Garyfalia; Thali, Yannick A; Schweitzer, Wolf; Hatch, Gary M; Ebert, Lars C; Thali, Michael J; Ruder, Thomas D

    2017-09-01

    The aim of this study was (1) to compare levels of accuracy regarding the categorization of causes of death between non-contrast post-mortem computed tomography (PMCT) and the final forensic report as well as between autopsy and the final forensic report, and (2) to assess levels of confidence regarding the categorization of causes of death after non-contrast PMCT and after autopsy. This prospective study was conducted over a 5 month period during which 221 cases were admitted to our institute for forensic investigations. Whole-body PMCT and forensic autopsy were performed in every case. Of these, 101 cases were included in the final study population. Inclusion criteria were: (1) age > 18 years, (2) presence of at least one of the two principal investigators at the time of admission. One radiologist and one forensic pathologist independently read all PMCT datasets using a report template. Cause of death category and confidence levels were determined by consensus. Forensic autopsy was performed by two forensic pathologists; both unblinded to imaging results. Both post-imaging and post-autopsy cause of death categorization were compared against the final cause of death, as stated in the forensic expert report, which included findings from histology and/or toxicology. Accuracy of post-imaging cause of death categorization in reference to the final cause of death category was substantial (82%, 83/101 cases, Kappa 0.752). Accuracy of post-autopsy cause of death categorization in reference to the final cause of death category was near perfect (89%, 90/101 cases, Kappa 0.852). Post-imaging sensitivity and specificity regarding the categorization of causes of death were 82% and 97%, respectively. Post-autopsy sensitivity and specificity regarding the categorization of causes of death were 89% and 98%, respectively. There was a high consistency between the accuracy of post-imaging cause of death categorization and post-imaging levels of confidence. There was less

  1. Noncontrast Myocardial T1 Mapping by Cardiac Magnetic Resonance Predicts Outcome in Patients With Aortic Stenosis.

    Science.gov (United States)

    Lee, Heesun; Park, Jun-Bean; Yoon, Yeonyee E; Park, Eun-Ah; Kim, Hyung-Kwan; Lee, Whal; Kim, Yong-Jin; Cho, Goo-Yeong; Sohn, Dae-Won; Greiser, Andreas; Lee, Seung-Pyo

    2017-11-10

    The aim of this study was to evaluate whether native T1 value of the myocardium on cardiac magnetic resonance (CMR) could predict clinical events in patients with significant aortic stenosis (AS). Although previous studies have demonstrated the prognostic value of focal fibrosis using late gadolinium enhancement (LGE) by CMR in AS patients, the prognostic implication of diffuse myocardial fibrosis by noninvasive imaging remains unknown. A prospective observational longitudinal study was performed in 127 consecutive patients with moderate or severe AS (68.8 ± 9.2 years of age, 49.6% male) and 33 age- and sex-matched controls who underwent 3-T CMR. The degree of diffuse myocardial fibrosis was assessed by noncontrast mapping of T1 relaxation time using modified Look-Locker inversion-recovery sequence, and the presence and extent of LGE were also evaluated. The AS patients were divided into 3 groups by the native T1 value. Primary endpoint was a composite of all-cause death and hospitalization for heart failure. Native T1 value was higher in AS patients, compared with control subjects (1,232 ± 53 ms vs. 1,185 ± 37 ms; p = 0.008). During follow-up (median 27.9 months), there were 24 clinical events including 9 deaths (6 pre-operative and 3 post-operative), the majority of which occurred in the patients in the highest T1 tertile group (2.4% vs. 11.6% vs. 42.9% for lowest, mid-, and highest tertile groups; p T1 tertile group. EuroSCORE II, the presence and/or extent of LGE, and the native T1 value were predictors of poor prognosis (adjusted hazard ratio for every 20-ms increase of native T1: 1.28; p = 0.003). In particular, the highest native T1 value provided further risk stratification regardless of the presence of LGE. High native T1 value on noncontrast T1 mapping CMR is a novel, independent predictor of adverse outcome in patients with significant AS. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  2. Assessment of early-stage optic nerve invasion in retinoblastoma using high-resolution 1.5 Tesla MRI with surface coils: a multicentre, prospective accuracy study with histopathological correlation

    Energy Technology Data Exchange (ETDEWEB)

    Brisse, Herve J. [Institut Curie, Department of Radiology, Paris (France); Institut CURIE, Imaging Department, Paris (France); Graaf, Pim de; Rodjan, Firazia; Jong, Marcus C. de; Castelijns, Jonas A. [VU University Medical Center, Department of Radiology, Amsterdam (Netherlands); Galluzzi, Paolo [Neuroimaging and Neurointerventional Unit (NINT) Azienda Ospedaliera e Universitaria Senese, Siena (Italy); Cosker, Kristel; Savignoni, Alexia [Institut Curie, Department of Biostatistics, Paris (France); Maeder, Philippe [Centre Hospitalier Universitaire Vaudois (CHUV) and University of Lausanne, Department of Radiology, Lausanne (Switzerland); Goericke, Sophia [University Hospital Essen, Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Aerts, Isabelle [Institut Curie, Department of Pediatric Oncology, Paris (France); Desjardins, Laurence [Institut Curie, Department of Ophthalmology, Paris (France); Moll, Annette C. [VU University Medical Center, Department of Ophthalmology, Amsterdam (Netherlands); Hadjistilianou, Theodora [Azienda Ospedaliera Universitaria Senese, Department of Ophthalmology, Siena (Italy); Toti, Paolo [University of Siena, Department of Medical Biotechnologies, Pathology Unit, Siena (Italy); Valk, Paul van der [VU University Medical Center, Department of Pathology, Amsterdam (Netherlands); Sastre-Garau, Xavier [Institut Curie, Department of Biopathology, Paris (France); Collaboration: European Retinoblastoma Imaging Collaboration (ERIC)

    2015-05-01

    To assess the accuracy of high-resolution (HR) magnetic resonance imaging (MRI) in diagnosing early-stage optic nerve (ON) invasion in a retinoblastoma cohort. This IRB-approved, prospective multicenter study included 95 patients (55 boys, 40 girls; mean age, 29 months). 1.5-T MRI was performed using surface coils before enucleation, including spin-echo unenhanced and contrast-enhanced (CE) T1-weighted sequences (slice thickness, 2 mm; pixel size <0.3 x 0.3 mm{sup 2}). Images were read by five neuroradiologists blinded to histopathologic findings. ROC curves were constructed with AUC assessment using a bootstrap method. Histopathology identified 41 eyes without ON invasion and 25 with prelaminar, 18 with intralaminar and 12 with postlaminar invasion. All but one were postoperatively classified as stage I by the International Retinoblastoma Staging System. The accuracy of CE-T1 sequences in identifying ON invasion was limited (AUC = 0.64; 95 % CI, 0.55 - 0.72) and not confirmed for postlaminar invasion diagnosis (AUC = 0.64; 95 % CI, 0.47 - 0.82); high specificities (range, 0.64 - 1) and negative predictive values (range, 0.81 - 0.97) were confirmed. HR-MRI with surface coils is recommended to appropriately select retinoblastoma patients eligible for primary enucleation without the risk of IRSS stage II but cannot substitute for pathology in differentiating the first degrees of ON invasion. (orig.)

  3. Transient osteoporosis of the hip, complete resolution after treatment with Alendronate as observed by MRI Description of 8 cases and review of the literature

    NARCIS (Netherlands)

    Emad, Y.; Ragab, Y.; El Shaarawy, Nashwa; Rasker, Hans J.

    2012-01-01

    Transient osteoporosis of the hip (TOH), also referred to as transient bone marrow edema syndrome, is most common in middle-aged men and often after trivial trauma or sport-related injuries. Diagnosis is usually made by eliminating other possible causes of hip pain. Magnetic resonance imaging (MRI)

  4. In vivo imaging of macrophages during the early-stages of abdominal aortic aneurysm using high resolution MRI in ApoE mice.

    Directory of Open Access Journals (Sweden)

    Yuyu Yao

    Full Text Available BACKGROUND: Angiotensin II (ANG II promotes vascular inflammation and induces abdominal aortic aneurysm (AAA in hyperlipidemic apolipoprotein E knock-out (apoE(-/- mice. The aim of the present study was to detect macrophage activities in an ANG II-induced early-stage AAA model using superparamagnetic iron oxide (SPIO as a marker. METHODOLOGY/PRINCIPAL FINDINGS: Twenty-six male apoE(-/- mice received saline or ANG II (1000 or 500 ng/kg/min infusion for 14 days. All animals underwent MRI scanning following administration of SPIO with the exception of three mice in the 1000 ng ANG II group, which were scanned without SPIO administration. MR imaging was performed using black-blood T2 to proton density -weighted multi-spin multi-echo sequence. In vivo MRI measurement of SPIO uptake and abdominal aortic diameter were obtained. Prussian blue, CD68,α-SMC and MAC3 immunohistological stains were used for the detection of SPIO, macrophages and smooth muscle cells. ANG II infusion with 1000 ng/kg/min induced AAA in all of the apoE(-/- mice. ANG II infusion exhibited significantly higher degrees of SPIO uptake, which was detected using MRI as a distinct loss of signal intensity. The contrast-to-noise ratio value decreased in proportion to an increase in the number of iron-laden macrophages in the aneurysm. The aneurysmal vessel wall in both groups of ANG II treated mice contained more iron-positive macrophages than saline-treated mice. However, the presence of cells capable of phagocytosing haemosiderin in mural thrombi also induced low-signal-intensities via MRI imaging. CONCLUSIONS/SIGNIFICANCE: SPIO is taken up by macrophages in the shoulder and the outer layer of AAA. This alters the MRI signaling properties and can be used in imaging inflammation associated with AAA. It is important to compare images of the aorta before and after SPIO injection.

  5. MRI Scans

    Science.gov (United States)

    Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from ...

  6. Fast Reference-Based MRI

    CERN Document Server

    Weizman, Lior; Ben-Basaht, Dafna

    2015-01-01

    In many clinical MRI scenarios, existing imaging information can be used to significantly shorten acquisition time or to improve Signal to Noise Ratio (SNR). In some cases, a previously acquired image can serve as a reference image, that may exhibit similarity to the image being acquired. Examples include similarity between adjacent slices in high resolution MRI, similarity between various contrasts in the same scan and similarity between different scans of the same patient. In this paper we present a general framework for utilizing reference images for fast MRI. We take into account that the reference image may exhibit low similarity with the acquired image and develop an iterative weighted approach for reconstruction, which tunes the weights according to the degree of similarity. Experiments demonstrate the performance of the method in three different clinical MRI scenarios: SNR improvement in high resolution brain MRI, utilizing similarity between T2-weighted and fluid-attenuated inversion recovery (FLAIR)...

  7. Utility of MRI for cervical spine clearance in blunt trauma patients after a negative CT.

    Science.gov (United States)

    Malhotra, Ajay; Durand, David; Wu, Xiao; Geng, Bertie; Abbed, Khalid; Nunez, Diego B; Sanelli, Pina

    2018-02-15

    To determine the utility of cervical spine MRI in blunt trauma evaluation for instability after a negative non-contrast cervical spine CT. A review of medical records identified all adult patients with blunt trauma who underwent CT cervical spine followed by MRI within 48 h over a 33-month period. Utility of subsequent MRI was assessed in terms of findings and impact on outcome. A total of 1,271 patients with blunt cervical spine trauma underwent both cervical spine CT and MRI within 48 h; 1,080 patients were included in the study analysis. Sixty-six percent of patients with a CT cervical spine study had a negative study. Of these, the subsequent cervical spine MRI had positive findings in 20.9%; 92.6% had stable ligamentous or osseous injuries, 6.0% had unstable injuries and 1.3% had potentially unstable injuries. For unstable injury, the NPV for CT was 98.5%. In all 712 patients undergoing both CT and MRI, only 1.5% had unstable injuries, and only 0.42% had significant change in management. MRI for blunt trauma evaluation remains not infrequent at our institution. MRI may have utility only in certain patients with persistent abnormal neurological examination. • MRI has limited utility after negative cervical CT in blunt trauma. • MRI is frequently positive for non-specific soft-tissue injury. • Unstable injury missed on CT is infrequent.

  8. High resolution three‐dimensional cine phase contrast MRI of small intracranial aneurysms using a stack of stars k‐space trajectory

    National Research Council Canada - National Science Library

    Kecskemeti, Steven; Johnson, Kevin; Wu, Yijing; Mistretta, Charles; Turski, Patrick; Wieben, Oliver

    2012-01-01

    ...) imaging with high spatial resolution in clinically feasible scan times. A hybrid radial-Cartesian k-space trajectory is used for cardiac gated, volumetric imaging with three directional velocity encoding...

  9. The accuracy of noncontrast spiral computerized tomography in detecting lucent renal stones: A case report and literature review

    Directory of Open Access Journals (Sweden)

    Ayman Adwan

    2015-01-01

    Full Text Available Renal stones are one of the most common diseases in the urology field that are easily diagnosed by one of the standard imaging techniques. Noncontrast spiral computerized tomography (CT can detect up to 95% of the renal, ureteric and bladder stones, especially those with calcium composition, and considered nowadays one of the most accurate methods for detecting undetectable stones by other modalities. We report a case of a 60-year-old female who presented with colicky right flank pain due to large calcium oxalate renal stone that is undetected by standard imaging technique including spiral CT scan. Uretroscopy diagnosed and ultimately treat this patient problem.

  10. The accuracy of noncontrast spiral computerized tomography in detecting lucent renal stones: A case report and literature review.

    Science.gov (United States)

    Adwan, Ayman; Binsaleh, Saleh

    2015-01-01

    Renal stones are one of the most common diseases in the urology field that are easily diagnosed by one of the standard imaging techniques. Noncontrast spiral computerized tomography (CT) can detect up to 95% of the renal, ureteric and bladder stones, especially those with calcium composition, and considered nowadays one of the most accurate methods for detecting undetectable stones by other modalities. We report a case of a 60-year-old female who presented with colicky right flank pain due to large calcium oxalate renal stone that is undetected by standard imaging technique including spiral CT scan. Uretroscopy diagnosed and ultimately treat this patient problem.

  11. Calculating the number of shock waves, expulsion time, and optimum stone parameters based on noncontrast computerized tomography characteristics.

    Science.gov (United States)

    Foda, Khaled; Abdeldaeim, Hussein; Youssif, Mohamed; Assem, Akram

    2013-11-01

    To define the parameters that accompanied a successful extracorporeal shock wave lithotripsy (ESWL), namely the number of shock waves (SWs), expulsion time (ET), mean stone density (MSD), and the skin-to-stone distance (SSD). A total of 368 patients diagnosed with renal calculi using noncontrast computerized tomography had their MSD, diameter, and SSD recorded. All patients were treated using a Siemens lithotripter. ESWL success meant a stone-free status or presence of residual fragments 934 HUs and SSD >99 mm. The required number of SWs and the expected ET can be anticipated. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. High resolution MRI of the breast at 3 T: which BI-RADS {sup registered} descriptors are most strongly associated with the diagnosis of breast cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Pinker-Domenig, K.; Helbich, T.H. [Medical University Vienna, Dept. of Radiology, Division of Molecular and Gender Imaging, Vienna (Austria); Bogner, W.; Gruber, S. [Medical University Vienna, Dept. of Radiology, MR Centre of Excellence, Vienna (Austria); Medical University Vienna, Dept. of Radiology, Vienna (Austria); Bickel, H. [Medical University Vienna, Dept. of Radiology, Division of Molecular and Gender Imaging, Vienna (Austria); Medical University Vienna, Dept. of Radiology, Vienna (Austria); Duffy, S. [Queen Mary University of London, Cancer Research UK Centre for Epidemiology, Mathematics and Statistics, Wolfson Institute of Preventive Medicine, Barts and The London School of Medicine and Dentistry, London (United Kingdom); Schernthaner, M. [Medical University Vienna, Dept. of Radiology, Vienna (Austria); Dubsky, P. [Medical University Vienna, Dept. of Surgery, Vienna (Austria); Pluschnig, U. [Medical University Vienna, Dept. of Internal Medicine, Division of Oncology, Vienna (Austria); Rudas, M. [Medical University Vienna, Clinical Institute of Pathology, Vienna (Austria); Trattnig, S. [Medical University Vienna, Dept. of Radiology, MR Centre of Excellence, Vienna (Austria)

    2012-02-15

    To identify which breast lesion descriptors in the ACR BI-RADS registered MRI lexicon are most strongly associated with the diagnosis of breast cancer when performing breast MR imaging at 3 T. 150 patients underwent breast MR imaging at 3 T. Lesion size, morphology and enhancement kinetics were assessed according to the BI-RADS {sup registered} classification. Sensitivity, specificity and diagnostic accuracy were assessed. The effects of the BI-RADS {sup registered} descriptors on sensitivity and specificity were evaluated. Data were analysed using logistic regression. Histopathological diagnoses were used as the standard of reference. The sensitivity, specificity and diagnostic accuracy of breast MRI at 3 T was 99%, 81% and 93%, respectively. In univariate analysis, the final diagnosis of malignancy was positively associated with irregular shape (p < 0.001), irregular margin (p < 0.001), heterogeneous enhancement (p < 0.001), Type 3 enhancement kinetics (p = 0.02), increasing patient age (p = 0.02) and larger lesion size (p < 0.001). In multivariate analysis, significant associations with malignancy remained for mass shape (p = 0.06), mass margin (p < 0.001), internal enhancement pattern (p = 0.03) and Type 3 enhancement kinetics (p = 0.06). The ACR BI-RADS {sup registered} breast lesion descriptors that are mostly strongly associated with breast cancer in breast MR imaging at 3 T are lesion shape, lesion margin, internal enhancement pattern and Type 3 enhancement kinetics. (orig.)

  13. Noncontrast chest computed tomography immediately after transarterial chemoembolization in patients with hepatocellular carcinoma: Clinical benefits and effect of radiation reduction on image quality in low-dose scanning

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Joon-Il [Center for Liver Cancer, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Department of Radiology, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Department of Radiology, Seoul St. Mary' s Hospital, The Catholic University of Korea, Seoul (Korea, Republic of); Kim, Hyun Beom, E-mail: dockhb@naver.com [Center for Liver Cancer, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Department of Radiology, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Kim, Min Ju; Lee, Jong Seok [Department of Radiology, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Koh, Young Whan; An, Sang Bu [Center for Liver Cancer, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Department of Radiology, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Ko, Heung-kyu [Department of Radiology, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Park, Joong-Won [Center for Liver Cancer, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of)

    2011-11-15

    Purpose: To evaluate the clinical benefits of noncontrast chest computed tomography (CT) immediately after transarterial chemoembolization in patients with hepatocellular carcinoma and to assess the effect of radiation reduction on image quality in low-dose scanning. Materials and methods: From June to October 2010, we performed standard-dose, noncontrast chest CTs immediately after transarterial chemoembolization in 160 patients and low-dose CTs in 88 patients. We reviewed the entire noncontrast chest CTs and follow-up CTs to reveal the clinical benefits of CT evaluation immediately after transarterial chemoembolization. Using two independent readers, we also retrospectively evaluated the radiation dose and image quality in terms of the image noise, contrast between the liver parenchyma and iodized oil and diagnostic acceptability for the evaluation of treatment response after transarterial chemoembolization. Results: In 5.2% of the patients, additional treatment was performed immediately after the interpretation of the noncontrast chest CT, and additional pulmonary lesions were found in 8.5% of the patients. The measured mean dose-length product for the low-dose scanning was 18.4% of that of the standard-dose scanning. The image noise was significantly higher with the low-dose scanning (p < 0.001). However, all of the low-dose CT scans were diagnostically acceptable, and the mean scores for the subjective assessments of the contrast and diagnostic acceptability showed no significant differences for either reader. Conclusion: A noncontrast chest CT immediately after transarterial chemoembolization has some clinical benefits for immediate decision making and detecting pulmonary lesions. Low-dose, noncontrast chest CTs immediately after transarterial chemoembolization consistently provide diagnostically acceptable images and information on treatment response in patients who have undergone transarterial chemoembolization.

  14. Devising an endoluminal bimodal probe which combines autofluorescence and reflectance spectroscopy with high resolution MRI for early stage colorectal cancer diagnosis: technique, feasibility and preliminary in-vivo (rabbit) results

    Science.gov (United States)

    Ramgolam, A.; Sablong, R.; Bou-Saïd, B.; Bouvard, S.; Saint-Jalmes, H.; Beuf, O.

    2011-07-01

    Conventional white light endoscopy (WLE) is the most widespread technique used today for colorectal cancer diagnosis and is considered as the gold standard when coupled to biopsy and histology. However for early stage colorectal cancer diagnosis, which is very often characterised by flat adenomas, the use of WLE is quite difficult due to subtle or quasiinvisible morphological changes of the colonic lining. Figures worldwide point out that diagnosing colorectal cancer in its early stages would significantly reduce the death toll all while increasing the 5-year survival rate. Several techniques are currently being investigated in the scope of providing new tools that would allow such a diagnostic or assist actual techniques in so doing. We hereby present a novel technique where High spatial Resolution MRI (HR-MRI) is coupled to optical spectroscopy (autofluorescence and reflectance) in a bimodal endoluminal probe to extract morphological data and biochemical information respectively. The design and conception of the endoluminal probe along with the preliminary results obtained with an organic phantom and in-vivo (rabbit) are presented and discussed.

  15. Application of 3D documentation and geometric reconstruction methods in traffic accident analysis: with high resolution surface scanning, radiological MSCT/MRI scanning and real data based animation.

    Science.gov (United States)

    Buck, Ursula; Naether, Silvio; Braun, Marcel; Bolliger, Stephan; Friederich, Hans; Jackowski, Christian; Aghayev, Emin; Christe, Andreas; Vock, Peter; Dirnhofer, Richard; Thali, Michael J

    2007-07-20

    The examination of traffic accidents is daily routine in forensic medicine. An important question in the analysis of the victims of traffic accidents, for example in collisions between motor vehicles and pedestrians or cyclists, is the situation of the impact. Apart from forensic medical examinations (external examination and autopsy), three-dimensional technologies and methods are gaining importance in forensic investigations. Besides the post-mortem multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) for the documentation and analysis of internal findings, highly precise 3D surface scanning is employed for the documentation of the external body findings and of injury-inflicting instruments. The correlation of injuries of the body to the injury-inflicting object and the accident mechanism are of great importance. The applied methods include documentation of the external and internal body and the involved vehicles and inflicting tools as well as the analysis of the acquired data. The body surface and the accident vehicles with their damages were digitized by 3D surface scanning. For the internal findings of the body, post-mortem MSCT and MRI were used. The analysis included the processing of the obtained data to 3D models, determination of the driving direction of the vehicle, correlation of injuries to the vehicle damages, geometric determination of the impact situation and evaluation of further findings of the accident. In the following article, the benefits of the 3D documentation and computer-assisted, drawn-to-scale 3D comparisons of the relevant injuries with the damages to the vehicle in the analysis of the course of accidents, especially with regard to the impact situation, are shown on two examined cases.

  16. The combined effect of hypertension and type 2 diabetes mellitus on aortic stiffness and endothelial dysfunction: an integrated study with high-resolution MRI.

    Science.gov (United States)

    Shan, Yan; Lin, Jiang; Xu, Pengju; Zeng, Mengsu; Lin, Huandong; Yan, Hongmei

    2014-04-01

    The purpose of this study was to investigate the combined effect of hypertension and type 2 diabetes mellitus (DM2) on aortic stiffness and endothelial dysfunction by using an integrated MRI approach. A total of 31 non-hypertensive DM2 patients and 31 hypertensive DM2 patients underwent 3.0-T MRI. Aortic distensibility (AD), pulse wave velocity (PWV) and brachial artery flow-mediated dilation (FMD) were assessed. Student's t-test, Mann-Whitney U test, chi-squared test, Pearson correlation analysis, and univariable and multiple linear regression analyses were used for statistical analyses. The hypertensive patients showed lower AD at multiple levels (ascending aorta [AA]: 2.07±0.98×10(-3)mm Hg(-1) vs. 3.21±1.70×10(-3)mm Hg(-1), p<0.01; proximal thoracic descending aorta [PDA]: 2.58±0.72×10(-3)mm Hg(-1) vs. 3.58±1.47×10(-3)mm Hg(-1), p<0.01; distal descending aorta [DDA]: 3.11±1.84×10(-3)mm Hg(-1) vs. 4.27±1.75×10(-3)mm Hg(-1), p<0.01); faster PWV (7.46±2.28m/s vs. 5.82±1.12m/s, p<0.05) and lower FMD (12.67%±6.49% vs. 20.66%±9.7%; p<0.01). Systolic blood pressure was an independent predictor of PWV, AA-AD, DDA-AD and FMD. FMD was statistically significantly associated with PWV (r=-0.37, p<0.01) and AD (p<0.01). Hypertension has a contributive effect on aortic stiffness and endothelial dysfunction in DM2 patients. © 2013.

  17. k-t accelerated aortic 4D flow MRI in under two minutes: Feasibility and impact of resolution, k-space sampling patterns, and respiratory navigator gating on hemodynamic measurements.

    Science.gov (United States)

    Bollache, Emilie; Barker, Alex J; Dolan, Ryan Scott; Carr, James C; van Ooij, Pim; Ahmadian, Rouzbeh; Powell, Alex; Collins, Jeremy D; Geiger, Julia; Markl, Michael

    2018-01-01

    To assess the performance of highly accelerated free-breathing aortic four-dimensional (4D) flow MRI acquired in under 2 minutes compared to conventional respiratory gated 4D flow. Eight k-t accelerated nongated 4D flow MRI (parallel MRI with extended and averaged generalized autocalibrating partially parallel acquisition kernels [PEAK GRAPPA], R = 5, TRes = 67.2 ms) using four ky -kz Cartesian sampling patterns (linear, center-out, out-center-out, random) and two spatial resolutions (SRes1 = 3.5 × 2.3 × 2.6 mm3 , SRes2 = 4.5 × 2.3 × 2.6 mm3 ) were compared in vitro (aortic coarctation flow phantom) and in 10 healthy volunteers, to conventional 4D flow (16 mm-navigator acceptance window; R = 2; TRes = 39.2 ms; SRes = 3.2 × 2.3 × 2.4 mm3 ). The best k-t accelerated approach was further assessed in 10 patients with aortic disease. The k-t accelerated in vitro aortic peak flow (Qmax), net flow (Qnet), and peak velocity (Vmax) were lower than conventional 4D flow indices by ≤4.7%, ≤ 11%, and ≤22%, respectively. In vivo k-t accelerated acquisitions were significantly shorter but showed a trend to lower image quality compared to conventional 4D flow. Hemodynamic indices for linear and out-center-out k-space samplings were in agreement with conventional 4D flow (Qmax ≤ 13%, Qnet ≤ 13%, Vmax ≤ 17%, P > 0.05). Aortic 4D flow MRI in under 2 minutes is feasible with moderate underestimation of flow indices. Differences in k-space sampling patterns suggest an opportunity to mitigate image artifacts by an optimal trade-off between scan time, acceleration, and k-space sampling. Magn Reson Med 79:195-207, 2018. © 2018 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  18. Prediction of differential creatinine clearance in chronically obstructed kidneys by non-contrast helical computerized tomography

    Directory of Open Access Journals (Sweden)

    Ng C.F.

    2004-01-01

    Full Text Available PURPOSE: We investigate the use of non-contrast helical computerized tomography (NCHCT in the measurement of differential renal parenchymal volume as a surrogate for differential creatinine clearance (CrCl for unilateral chronically obstructed kidney. MATERIALS AND METHODS: Patients with unilateral chronically obstructed kidneys with normal contralateral kidneys were enrolled. Ultrasonography (USG of the kidneys was first done with the cortical thickness of the site with the most renal substance in the upper pole, mid-kidney, and lower pole of both kidneys were measured, and the mean cortical thickness of each kidney was calculated. NCHCT was subsequently performed for each patient. The CT images were individually reviewed with the area of renal parenchyma measured for each kidney. Then the volume of the slices was summated to give the renal parenchymal volume of both the obstructed and normal kidneys. Finally, a percutaneous nephrostomy (PCN was inserted to the obstructed kidney, and CrCl of both the obstructed kidney (PCN urine and the normal side (voided urine were measured two 2 after the relief of obstruction. RESULTS: From March 1999 to February 2001, thirty patients were enrolled into the study. Ninety percent of them had ureteral calculi. The differential CrCl of the obstructed kidney (%CrCl was defined as the percentage of CrCl of the obstructed kidney as of the total CrCl, measured 2 weeks after relief of obstruction. The differential renal parenchymal volume of the obstructed kidney (%CTvol was the percentage of renal parenchymal volume as of the total parenchymal volume. The differential USG cortical thickness of the obstructed kidney (%USGcort was the percentage of mean cortical thickness as of the total mean cortical thickness. The Pearson's correlation coefficient (r between %CTvol and %CrCl and that between %USGcort and %CrCl were 0.756 and 0.543 respectively. The regression line was %CrCl = (1.00 x %CTvol - 14.27. The %CTvol

  19. The utility of noncontrast computed tomography in the prompt diagnosis of postoperative complications after percutaneous nephrolithotomy.

    Science.gov (United States)

    Gnessin, Ehud; Mandeville, Jessica A; Handa, Shelly E; Lingeman, James E

    2012-04-01

    Noncontrast computed tomography (CT) is commonly utilized after percutaneous nephrolithotomy (PNL) to assess stone-free (SF) status. In addition to assessing SF status, CT is useful in the recognition of complications after PNL. We characterized complications demonstrated by postoperative CT scan and compared hospital re-admission rates based on whether or not CT was performed. We retrospectively reviewed records of 1032 consecutive patients from April 1999 to June 2010. Patients were divided into two cohorts based on whether they had a CT within 24 hours of PNL. Demographic data, CT findings, and need for re-admission for complication management were assessed. Nine hundred fifty-seven patients (92.7%) underwent post-PNL CT. CT-diagnosed complications were perinephric hematoma in 41 (4.3%; 2 requiring embolization and 9 necessitating transfusion), pleural effusion in 25 (2.6%; 10 requiring intervention), colon perforation in 2 (0.2%), and splenic injury in 2 (0.2%). Of patients with postoperative complications, 33% required intervention. Among patients with a CT, 6 (0.6%) were readmitted despite negative postoperative CT (four perinephric hematomas, one calyceal-pleural fistula, and one pseudoaneurysm). The sensitivity of CT for diagnosing complications was 92.7%. Seventy-five patients (7.3%) did not undergo CT post-PNL. Of these, four (5.33%) were readmitted: three for perinephric hematomas and one for ureteral clot obstruction. Patients undergoing post-PNL CT were less likely to be readmitted because of missed complications (p=0.02). Serious post-PNL complications are uncommon, but their prompt diagnosis and treatment is imperative. In addition to identifying residual stones, CT is useful in diagnosing postoperative complications. Postoperative CT could potentially be considered for all patients undergoing PNL, particularly in complex cases such as patients with anatomical abnormalities (renal anatomic abnormality or retrorenal colon), patients requiring upper

  20. Clinical impact of gadolinium in the MRI diagnosis of musculoskeletal infection in children

    Energy Technology Data Exchange (ETDEWEB)

    Kan, J.H.; Young, Robert S.; Hernanz-Schulman, Marta [Vanderbilt University, Department of Radiology and Radiological Sciences, Vanderbilt Children' s Hospital, Nashville, TN (United States); Yu, Chang [Vanderbilt University, Department of Biostatistics, Nashville, TN (United States)

    2010-07-15

    The incremental value of gadolinium in the diagnosis of musculoskeletal infection by MRI is controversial. To compare diagnostic utility of noncontrast with contrast MRI in the evaluation of pediatric musculoskeletal infections. We reviewed 90 gadolinium-enhanced MRIs in children with suspected musculoskeletal infection. Noncontrast and contrast MRI scans were evaluated to determine sensitivity and specificity in the diagnosis of musculoskeletal infection and identification of abscesses. Pre- and post-contrast diagnosis of osteomyelitis sensitivity was 89% and 91% (P = 1.00) and specificity was 96% and 96% (P = 1.00), respectively; septic arthritis sensitivity was 50% and 67% (P = 1.00) and specificity was 98% and 98% (P = 1.00), respectively; cellulitis/myositis sensitivity was 100% and 100% (P = 1.00) and specificity was 84% and 88% (P = 0.59), respectively; abscess for the total group was 22 (24.4%) and 42 (46.6%), respectively (P < 0.0001). Abscesses identified only on contrast sequences led to intervention in eight additional children. No child with a final diagnosis of infection had a normal pre-contrast study. Intravenous gadolinium should not be routinely administered in the imaging work-up of nonspinal musculoskeletal infections, particularly when pre-contrast images are normal. However, gadolinium contrast significantly increases the detection of abscesses, particularly small ones that might not require surgical intervention. (orig.)

  1. Magnetoacoustic tomography with magnetic induction for high-resolution bioimepedance imaging through vector source reconstruction under the static field of MRI magnet.

    Science.gov (United States)

    Mariappan, Leo; Hu, Gang; He, Bin

    2014-02-01

    Magnetoacoustic tomography with magnetic induction (MAT-MI) is an imaging modality to reconstruct the electrical conductivity of biological tissue based on the acoustic measurements of Lorentz force induced tissue vibration. This study presents the feasibility of the authors' new MAT-MI system and vector source imaging algorithm to perform a complete reconstruction of the conductivity distribution of real biological tissues with ultrasound spatial resolution. In the present study, using ultrasound beamformation, imaging point spread functions are designed to reconstruct the induced vector source in the object which is used to estimate the object conductivity distribution. Both numerical studies and phantom experiments are performed to demonstrate the merits of the proposed method. Also, through the numerical simulations, the full width half maximum of the imaging point spread function is calculated to estimate of the spatial resolution. The tissue phantom experiments are performed with a MAT-MI imaging system in the static field of a 9.4 T magnetic resonance imaging magnet. The image reconstruction through vector beamformation in the numerical and experimental studies gives a reliable estimate of the conductivity distribution in the object with a ∼ 1.5 mm spatial resolution corresponding to the imaging system frequency of 500 kHz ultrasound. In addition, the experiment results suggest that MAT-MI under high static magnetic field environment is able to reconstruct images of tissue-mimicking gel phantoms and real tissue samples with reliable conductivity contrast. The results demonstrate that MAT-MI is able to image the electrical conductivity properties of biological tissues with better than 2 mm spatial resolution at 500 kHz, and the imaging with MAT-MI under a high static magnetic field environment is able to provide improved imaging contrast for biological tissue conductivity reconstruction.

  2. MRI in Optic Neuritis: Structure, Function, Interactions

    DEFF Research Database (Denmark)

    Fuglø, Dan

    2011-01-01

    resonance imaging (MRI), and the visual evoked potential (VEP) continues to show a delayed P100 indicating persistent demyelination. The explanation for this apparent discrepancy between structure and function could be due to either a redundancy in the visual pathways so that some degree of signal loss...... are low. Functional MRI (fMRI) is a non-invasive technique that can measure brain activity with a high spatial resolution. Recently, technical and methodological advancements have made it feasible to record VEPs and fMRI simultaneously and the relationship between averaged VEPs and averaged fMRI signals...... have been described. Still, to take full advantage of simultaneously recorded VEP-fMRI one would ideally want to track single-trial changes in the VEP and use this information in the fMRI analysis. In order to do this we examined 10 healthy volunteers with simultaneous VEP-fMRI. Different measures...

  3. Comparison of high resolution whole-body MRI using parallel imaging and PET-CT. First experiences with a 32-channel MRI system; Hochaufloesendes Ganzkoerpertumorstaging unter Verwendung paralleler Bildgebung im Vergleich zur PET-CT. Erste Erfahrungen auf einem 32-Kanal-MRT-System

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, G.P.; Baur-Melnyk, A.; Reiser, M.F.; Schoenberg, S.O. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen, Institut fuer Klinische Radiologie (Germany); Tiling, R.; Hahn, K. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen, Klinik und Poliklinik fuer Nuklearmedizin (Germany)

    2004-09-01

    To compare the accuracy in the detection and staging of various malignant tumors with high resolution whole-body MRI using parallel imaging with whole-body dual-modality PET-CT. Preliminary results of an interim analysis from a prospective, blinded study are presented, in which 20 patients (mean age 59 years, range 27-77 years) with different oncological diseases underwent whole-body dual modality FDG-PET-CT screening for tumor search or staging in case of confirmed or suspected metastatic disease. All patients also underwent whole-body MRI imaging with the use of parallel imaging (iPAT). High-resolution coronal T1w- and STIR-sequences of 5 body levels with 512 x 512 matrix, axial fast T2w imaging of lung and abdomen (HASTE), contrast-enhanced dynamic and static T1w-sequences of liver, brain, abdomen, and pelvis were performed. Using a 32-channel whole-body MRI scanner (Magnetom Avanto, Siemens Medical Solutions) with a total field of view of 205 cm and free table movement, all patients could be covered from head to toe within one examination. With this technique, high spatial resolution and acceptable scanning times could be obtained. Two experienced radiologists read the MRI-scans, one radiologist and one nuclear scientist read PET-CT scans, each in consensus in a clinical setting. Delineation of the primary tumor (T-stage) or recurrent tumor, pathologic lymph node involvement, as well as degree and localization of metastatic disease, was assessed using PET-CT as standard of reference. Metastases from gastrointestinal tumor (25%) and breast cancer (25%), genitourinary tumor (15%) and malignant melanoma (15%) were detected. In 4/20 patients the primary tumor was identified, 2/20 patients showed recurrent tumor. Of 140 malignant lesions detected by PET-CT, 124 lesions were detected with MRI, resulting in a sensitivity of 89% at a specificity of 86%. In malignant lymph node detection, sensitivity of MRI was 83% and specificity 85%. Whole-body MRI is a promising

  4. High Field Atherosclerotic Plaque MRI

    OpenAIRE

    Yuan, Chun; Wang, Jinnan; Balu, Niranjan

    2012-01-01

    Manifestations of atherosclerotic plaque in different arterial beds range from perfusion deficits to overt ischemia such as stroke and myocardial infarction. Atherosclerotic plaque composition is known to be associated with its propensity to rupture and cause vascular events. MRI of atherosclerotic plaque using clinical 1.5T scanners can detect plaque composition. Plaque MRI at higher field strengths offers both opportunities and challenges to improving the high spatial-resolution and contras...

  5. Non-contrast enhanced navigator-gated balanced steady state free precession magnetic resonance angiography as a preferred magnetic resonance technique for assessment of the thoracic aorta

    NARCIS (Netherlands)

    van Kesteren, F.; Elattar, M. A.; van Lienden, K. P.; Baan, J.; Marquering, H. A.; Planken, R. N.

    2017-01-01

    AIM: To compare the objective and subjective image quality of non-contrast three-dimensional (3D) navigator-gated balanced steady state free precession magnetic resonance angiography (NC-MRA) and contrast-enhanced magnetic resonance angiography (CE-MRA) along the entire thoracic aorta. MATERIALS AND

  6. Effect of Intensive Statin Therapy on Coronary High-Intensity Plaques Detected by Noncontrast T1-Weighted Imaging: The AQUAMARINE Pilot Study.

    Science.gov (United States)

    Noguchi, Teruo; Tanaka, Atsushi; Kawasaki, Tomohiro; Goto, Yoichi; Morita, Yoshiaki; Asaumi, Yasuhide; Nakao, Kazuhiro; Fujiwara, Reiko; Nishimura, Kunihiro; Miyamoto, Yoshihiro; Ishihara, Masaharu; Ogawa, Hisao; Koga, Nobuhiko; Narula, Jagat; Yasuda, Satoshi

    2015-07-21

    Coronary high-intensity plaques detected by noncontrast T1-weighted imaging may represent plaque instability. High-intensity plaques can be quantitatively assessed by a plaque-to-myocardium signal-intensity ratio (PMR). This pilot, hypothesis-generating study sought to investigate whether intensive statin therapy would lower PMR. Prospective serial noncontrast T1-weighted magnetic resonance imaging and computed tomography angiography were performed in 48 patients with coronary artery disease at baseline and after 12 months of intensive pitavastatin treatment with a target low-density lipoprotein cholesterol level parameters and high-sensitivity C-reactive protein levels were analyzed. In the statin group, 12 months of statin therapy significantly improved low-density lipoprotein cholesterol levels (125 to 70 mg/dl; p intensity plaques. Noncontrast T1-weighted magnetic resonance imaging could become a useful technique for repeated quantitative assessment of plaque composition. (Attempts at Plaque Vulnerability Quantification with Magnetic Resonance Imaging Using Noncontrast T1-weighted Technique [AQUAMARINE]; UMIN000003567). Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  7. MRI features of peripheral traumatic neuromas

    Energy Technology Data Exchange (ETDEWEB)

    Ahlawat, Shivani [Johns Hopkins University School of Medicine, Musculoskeletal Radiology Section, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Belzberg, Allan J. [The Johns Hopkins Hospital, Department of Neurosurgery, Baltimore, MD (United States); Montgomery, Elizabeth A. [The Johns Hopkins Hospital, Pathology, Oncology and Orthopedic Surgery, Baltimore, MD (United States); Fayad, Laura M. [Department of Orthopedic Surgery, Department of Radiology and Radiological Science, Musculoskeletal Imaging Section Chief, The Johns Hopkins Medical Institutions, Baltimore, MD (United States); The Johns Hopkins Medical Institutions, Department of Orthopedic Surgery, Baltimore, MD (United States)

    2016-04-15

    To describe the MRI appearance of traumatic neuromas on non-contrast and contrast-enhanced MRI sequences. This IRB-approved, HIPAA-compliant study retrospectively reviewed 13 subjects with 20 neuromas. Two observers reviewed pre-operative MRIs for imaging features of neuroma (size, margin, capsule, signal intensity, heterogeneity, enhancement, neurogenic features and denervation) and the nerve segment distal to the traumatic neuroma. Descriptive statistics were reported. Pearson's correlation was used to examine the relationship between size of neuroma and parent nerve. Of 20 neuromas, 13 were neuromas-in-continuity and seven were end-bulb neuromas. Neuromas had a mean size of 1.5 cm (range 0.6-4.8 cm), 100 % (20/20) had indistinct margins and 0 % (0/20) had a capsule. Eighty-eight percent (7/8) showed enhancement. All 100 % (20/20) had tail sign; 35 % (7/20) demonstrated discontinuity from the parent nerve. None showed a target sign. There was moderate positive correlation (r = 0.68, p = 0.001) with larger neuromas arising from larger parent nerves. MRI evaluation of the nerve segment distal to the neuroma showed increased size (mean size 0.5 cm ± 0.4 cm) compared to the parent nerve (mean size 0.3 cm ± 0.2 cm). Since MRI features of neuromas include enhancement, intravenous contrast medium cannot be used to distinguish neuromas from peripheral nerve sheath tumours. The clinical history of trauma with the lack of a target sign are likely the most useful clues. (orig.)

  8. Noninvasive detection of coronary artery wall thickening with age in healthy subjects using high resolution MRI with beat-to-beat respiratory motion correction.

    Science.gov (United States)

    Scott, Andrew D; Keegan, Jennifer; Mohiaddin, Raad H; Firmin, David N

    2011-10-01

    To demonstrate coronary artery wall thickening with age in a small healthy cohort using a highly efficient, reliable, and reproducible high-resolution MR technique. A 3D cross-sectional MR vessel wall images (0.7 × 0.7 × 3 mm resolution) with retrospective beat-to-beat respiratory motion correction (B2B-RMC) were obtained in the proximal right coronary artery of 21 healthy subjects (age, 22-62 years) with no known cardiovascular disease. Lumen and outer wall (lumen + vessel wall) areas were measured in one central slice from each subject and average wall thickness and wall area/outer wall area ratio (W/OW) calculated. Imaging was successful in 18 (86%) subjects with average respiratory efficiency 99.3 ± 1.7%. Coronary vessel wall thickness and W/OW significantly correlate with subject age, increasing by 0.088 mm and 0.031 per decade respectively (R = 0.53, P = 0.024 and R = 0.48, P = 0.046). No relationship was found between lumen area and vessel wall thickness (P = NS), but outer wall area increased significantly with vessel wall thickness at 19 mm(2) per mm (P = 0.046). This is consistent with outward vessel wall remodeling. Despite the small size of our healthy cohort, using high-resolution MR imaging and B2B-RMC, we have demonstrated increasing coronary vessel wall thickness and W/OW with age. The results obtained are consistent with outward vessel wall remodeling. Copyright © 2011 Wiley-Liss, Inc.

  9. MRI of the Chest

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Chest Magnetic resonance imaging (MRI) of the chest ... limitations of MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) is ...

  10. MRI of the Prostate

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Prostate Magnetic resonance imaging (MRI) of the prostate ... limitations of MRI of the Prostate? What is MRI of the Prostate? Magnetic resonance imaging (MRI) is ...

  11. MRI of the Breast

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Breast Magnetic resonance imaging (MRI) of the breast ... limitations of MRI of the Breast? What is MRI of the Breast? Magnetic resonance imaging (MRI) is ...

  12. MRI of the Chest

    Medline Plus

    Full Text Available ... This detail makes MRI an invaluable tool in early diagnosis and evaluation of cardiovascular conditions. MRI has ... Magnetic Resonance Imaging (MRI) Safety MRI Safety During Pregnancy Images related to Magnetic Resonance Imaging (MRI) - Chest ...

  13. High resolution three-dimensional cine phase contrast MRI of small intracranial aneurysms using a stack of stars k-space trajectory.

    Science.gov (United States)

    Kecskemeti, Steven; Johnson, Kevin; Wu, Yijing; Mistretta, Charles; Turski, Patrick; Wieben, Oliver

    2012-03-01

    To develop a method for targeted volumetric, three directional cine phase contrast (PC) imaging with high spatial resolution in clinically feasible scan times. A hybrid radial-Cartesian k-space trajectory is used for cardiac gated, volumetric imaging with three directional velocity encoding. Imaging times are reduced by radial undersampling and temporal viewsharing. Phase contrast angiograms are displayed in a new approach that addresses the concern of signal drop out in regions of slow flow. The feasibility of the PC stack of stars (SOS) trajectory was demonstrated with an in vivo study capturing 14 small intracranial aneurysms (2-10 mm). Aneurysm measures from six aneurysms also imaged with digital subtraction angiography (DSA) were compared with linear regression with those from the PC SOS images. All aneurysms were identified on the phase contrast angiograms. The geometric measures from PC SOS and DSA were in good agreement (linear regression: slope = 0.89, intercept = 0.35, R∧2 = 0.88). PC SOS is a promising method for obtaining volumetric angiograms and cine phase contrast velocity measurements in three dimensions. Acquired spatial resolutions of 0.4 × 0.4 × (0.7-1.0) mm make this method especially promising for studying flow in small intracranial aneurysms. Copyright © 2011 Wiley-Liss, Inc.

  14. MRI zoo

    DEFF Research Database (Denmark)

    Laustsen, Christoffer

    The basic idea was to use MRI to produce a sequence of 3D gray scale image slices of various animals, subsequentlyimaged with a clinical CT system. For this purpose, these animals were used: toad, lungfish, python snake and a horseshoe crab. Each animal was sacrificed according to standard....... MRI was done using a Philips Achieva 1.5 T system and CT was performed using a Siemens Somatom system. Axial and sagittal slices were acquired using standard T1w and T2w MRI sequences, and visualization was made using the Mistar software (Apollo Imaging Technology, Melbourne, Australia). Images were...

  15. Pediatric MRI

    Data.gov (United States)

    U.S. Department of Health & Human Services — The NIH Study of Normal Brain Development is a longitudinal study using anatomical MRI, diffusion tensor imaging (DTI), and MR spectroscopy (MRS) to map pediatric...

  16. Cardiac MRI

    Science.gov (United States)

    ... Activities Obesity, Nutrition, and Physical Activity Population and Epidemiology Studies Women’s Health All Science A-Z Grants & ... interfere with the MRI machine or cause skin burns. Tattoos may cause a problem because older tattoo ...

  17. Chest MRI

    Science.gov (United States)

    ... Activities Obesity, Nutrition, and Physical Activity Population and Epidemiology Studies Women’s Health All Science A-Z Grants & ... interfere with the MRI machine or cause skin burns. Tattoos may cause a problem because older tattoo ...

  18. Head MRI

    Science.gov (United States)

    ... metal zippers, and similar metallic items Removable dental work ... test. The strong magnetic fields created during an MRI can make heart pacemakers and other implants not work as well. It can also cause a piece ...

  19. Low radiation dose non-contrast cardiac CT: is it of value in the evaluation of mechanical aortic valve

    Energy Technology Data Exchange (ETDEWEB)

    Bazeed, Mohamed Fayez (Dept. of Diagnostic Radiology, Faculty of Medicine, Mansoura Univ. (Egypt)), email: m_bazeed@yahoo.com; Moselhy, Mohamed Saleh (Cardiology Dept. Faculty of Medicine, Suez Canal Univ. (Egypt)); Rezk, Ahmad Ibrahim (Dept. of Cardiac Surgery, Faculty of Medicine, Aim Shams Univ. (Egypt)); Al-Murayeh, Mushabab Ayedh (Dept. of Cardiac Services, Armed Forces Hospitals Southern Region (Saudi Arabia))

    2012-05-15

    Background: Prosthetic bileaflet mechanical valve function has been traditionally evaluated using echocardiography and fluoroscopy. Multidetector computed tomography (MDCT) is a novel technique for cardiac evaluation. Purpose: To evaluate bileaflet mechanical aortic valves using a low-milliampere (mA), non-contrast MDCT protocol with a limited scan range. Material and Methods: Forty patients with a bileaflet mechanical aortic valve were evaluated using a non-contrast, low-mA, ECG-gated 64 MDCT protocol with a limited scan range. MDCT findings of opening and closing valve angles were correlated to fluoroscopy and echocardiography. Also, the valve visibility was evaluated on MDCT and fluoroscopy according to a 3-point grading scale. Results: The visualization score with the MDCT was significantly superior to the fluoroscopy (3 vs. 2.7). A strong correlation was noted between the opening (r = 0.82) and closing (r = 0.96) valve angles with MDCT and fluoroscopy without a statistically significant difference (P = 0.31 and 0.16, respectively). The mean effective radiation dose of the suggested protocol was 4 +- 0.5 mSv. Five valves were evaluated using transesophageal echocardiography because the valves were difficult to evaluate with transthoracic echocardiography, and all of these valves were evaluated optimally with MDCT. A high-pressure gradient was noted in nine valves, and the MDCT showed that seven of these valves inadequately opened, and two valves opened well, which resulted in patient valve mismatch. Incomplete valve closure was noted in five valves, and the echocardiography showed significant transvalvular regurgitation in all five valves. Conclusion: MDCT can provide a precise measurement of valve function and can potentially evaluate high-pressure gradients and transvalvular regurgitation

  20. Relationship of epicardial fat volume from noncontrast CT with impaired myocardial flow reserve by positron emission tomography.

    Science.gov (United States)

    Otaki, Yuka; Hell, Michaela; Slomka, Piotr J; Schuhbaeck, Annika; Gransar, Heidi; Huber, Brandi; Nakazato, Ryo; Germano, Guido; Hayes, Sean W; Thomson, Louise E J; Friedman, John D; Achenbach, Stephan; Berman, Daniel S; Dey, Damini

    2015-01-01

    Impaired myocardial flow reserve (MFR) is a marker of coronary vascular dysfunction with prognostic significance. We aimed to investigate the relationship between epicardial fat volume (EFV) measured from noncontrast CT and impaired MFR derived from rest-stress Rb-82 positron emission tomography (PET). We retrospectively studied 85 consecutive patients without known coronary artery disease who underwent rest-stress Rb-82 myocardial PET/CT and were subsequently referred for invasive coronary angiography. EFV was computed from noncontrast CT by validated software and indexed to body surface area (EFVi, cm3/m2). Global stress and rest MFR were automatically derived from PET. Patient age, sex, cardiovascular risk factors, coronary calcium score (CCS), and EFVi were combined by boosted ensemble machine learning algorithm into a novel composite risk score, using 10-fold cross-validation, to predict impaired global MFR (MFR ≤2.0) by PET. Patients with impaired MFR (44 of 85; 52%) were older (71 vs. 65 years; P = .03) and had higher frequency of CCS (≥400; P = .02) with significantly higher EFVi (63.1 ± 20.4 vs. 51.3 ± 14.1 cm3/m2; P = .003). On multivariate logistic regression (with age, sex, number of risk factors, CCS, and EFVi), EFVi was the only independent predictor of impaired MFR (odds ratio, 7.39; P = .02). The machine learning composite risk score significantly improved risk reclassification of impaired MFR compared to CCS or EFVi alone (integrated discrimination improvement = 0.19; P = .007 and IDI = 0.22; P = .002, respectively). Increased EFVi and composite risk score combining EFVi and CCS significantly improve identification of impaired global MFR by PET. Copyright © 2015 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  1. Spontaneous intracranial hypotension: use of unenhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Quinones Tapia, D.; Lopez-Ibor, L. [Dept. of Neuroradiology, Clinica de La Zarzuela, Aravaca, Madrid (Spain); Pardo, J.; Anciones, V. [Dept. of Neurology, Clinica de La Zarzuela, Aravaca, Madrid (Spain); Serrano, J.M. [Dept. of Ophthalmology, Fundacion Jimenez Diaz, Madrid (Spain)

    2000-07-01

    We report a case of spontaneous intracranial hypotension diagnosed with unenhanced cranial MRI, showing laminar subdural fluid and engorgement of the hypophysis and perisellar sinuses. Cerebrospinal fluid pressure was low. MRI was normal after resolution of symptoms. Prior reports emphasise the enhancing pachymeninges seen in this syndrome. We maintain that, when subdural collections and perisellar engorgement are detected on unenhanced MRI in the proper clinical setting, contrast enhancement may not be necessary for the diagnosis. (orig.)

  2. Clinical indications for high-resolution MRI diagnostics of the peripheral nervous system; Klinische Indikationen hochaufloesender MRT-Diagnostik des peripheren Nervensystems

    Energy Technology Data Exchange (ETDEWEB)

    Godel, T. [Universitaetsklinikum Heidelberg, Abteilung fuer Neuroradiologie, Heidelberg (Germany); Weiler, M. [Universitaetsklinikum Heidelberg, Neurologische Klinik, Heidelberg (Germany)

    2017-03-15

    Peripheral neuropathies are common and diagnostically often challenging disorders. Difficulties particularly exist in lesion localization and recognition of complex spatial lesion patterns. Medical history taking, neurological examination, neurophysiological tests and nerve ultrasonography represent the gold standard in the diagnosis of peripheral nerve lesions but have known methodical limitations. The use of 3 Tesla magnetic resonance neurography (MRN) is an additional diagnostic imaging tool recently developed for the high-resolution visualization of long segments of peripheral nerves. Reasonable clinical indications for MRN are exemplarily presented. Using MRN a direct visualization and thus precise localization of focal and non-focal peripheral nerve lesions of various origins can be achieved with high spatial resolution down to the anatomical level of nerve fascicles. Using MRN large anatomical areas of the peripheral nervous system (PNS) can be covered in a single examination session, spatial nerve lesion patterns can be evaluated and the underlying causes can often be detected. The MRN is a valuable supplement to the diagnostic work-up of the PNS, especially in cases that cannot be clarified with standard diagnostic methods. Evaluation of the spatial nerve lesion pattern gives additional information on the origin of the underlying disease. Reasonable indications for MRN are the assessment of proximal nerve structures including the brachial and lumbosacral nerve plexi, the clarification of inconclusive diagnostic results, preoperative, postoperative and posttraumatic assessments, the identification of fascicular nerve lesions and the differential diagnosis of an alleged somatoform disorder. (orig.) [German] Periphere Neuropathien sind haeufige und diagnostisch mitunter anspruchsvolle Erkrankungen. Schwierigkeiten bestehen v. a. bei der Laesionslokalisation und Erkennung komplexer Laesionsmuster. Anamnese, klinisch-neurologische Untersuchung

  3. Superresolution improves MRI cortical segmentation with FACE

    DEFF Research Database (Denmark)

    Eskildsen, Simon Fristed; Manjón, José V.; Coupé, Pierrick

    Brain cortical surface extraction from MRI has applications for measurement of gray matter (GM) atrophy, functional mapping, source localization and preoperative neurosurgical planning. Accurate cortex segmentation requires high resolution morphological images and several methods for extracting...

  4. Non-contrast CT at comparable dose to an abdominal radiograph in patients with acute renal colic; impact of iterative reconstruction on image quality and diagnostic performance.

    Science.gov (United States)

    McLaughlin, P D; Murphy, K P; Hayes, S A; Carey, K; Sammon, J; Crush, L; O'Neill, F; Normoyle, B; McGarrigle, A M; Barry, J E; Maher, M M

    2014-04-01

    The aim was to assess the performance of low-dose non-contrast CT of the urinary tract (LD-CT) acquired at radiation exposures close to that of abdominal radiography using adaptive statistical iterative reconstruction (ASiR). Thirty-three patients with clinically suspected renal colic were prospectively included. Conventional dose (CD-CT) and LD-CT data sets were contemporaneously acquired. LD-CT images were reconstructed with 40 %, 70 % and 90 % ASiR. Image quality was subjectively and objectively measured. Images were also clinically interpreted. Mean ED was 0.48 ± 0.07 mSv for LD-CT compared with 4.43 ± 3.14 mSv for CD-CT. Increasing the percentage ASiR resulted in a step-wise reduction in mean objective noise (p ASiR LD-CT images had higher diagnostic acceptability and spatial resolution than 90 % ASiR LD-CT images (p ASiR LD-CT with two false positives and 16 false negatives (diameter = 2.3 ± 0.7 mm) equating to a sensitivity and specificity of 72 % and 94 %. Seventy % ASiR LD-CT had a sensitivity and specificity of 87 % and 100 % for detection of calculi >3 mm. Reconstruction of LD-CT images with 70 % ASiR resulted in superior image quality than FBP, 40 % ASIR and 90 % ASIR. LD-CT with ASIR demonstrates high sensitivity and specificity for detection of calculi >3 mm. • Low-dose CT studies for urinary calculus detection were performed with a mean dose of 0.48 ± 0.07 mSv • Low-dose CT with 70 % ASiR detected calculi >3 mm with a sensitivity and specificity of 87 % and 100 % • Reconstruction with 70 % ASiR was superior to filtered back projection, 40 % ASiR and 90 % ASiR images.

  5. Resolving MRI abnormalities with progression of subacute sclerosing panencephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Winer, J.B. (Saint Mary' s Hospital, Birmingham (UK)); Pires, M.; Kermode, A.; Ginsberg, L. (National Hospital for Nervous Diseases, Birmingham (UK)); Rossor, M. (Saint Mary' s Hospital, Birmingham (UK) National Hospital for Nervous Diseases, Birmingham (UK))

    1991-04-01

    Serial MRI was performed on a 15 year old girl with Subacute Sclerosing Pan-encephalitis (SSPE). After a period of remission she entered a phase of progressive deterioration. A repeat MRI showed significant resolution of the previous abnormalities. Her pathology and MRI scans are discussed.

  6. MRI-powered biomedical devices.

    Science.gov (United States)

    Hovet, Sierra; Ren, Hongliang; Xu, Sheng; Wood, Bradford; Tokuda, Junichi; Tse, Zion Tsz Ho

    2017-11-16

    Magnetic resonance imaging (MRI) is beneficial for imaging-guided procedures because it provides higher resolution images and better soft tissue contrast than computed tomography (CT), ultrasound, and X-ray. MRI can be used to streamline diagnostics and treatment because it does not require patients to be repositioned between scans of different areas of the body. It is even possible to use MRI to visualize, power, and control medical devices inside the human body to access remote locations and perform minimally invasive procedures. Therefore, MR conditional medical devices have the potential to improve a wide variety of medical procedures; this potential is explored in terms of practical considerations pertaining to clinical applications and the MRI environment. Recent advancements in this field are introduced with a review of clinically relevant research in the areas of interventional tools, endovascular microbots, and closed-loop controlled MRI robots. Challenges related to technology and clinical feasibility are discussed, including MRI based propulsion and control, navigation of medical devices through the human body, clinical adoptability, and regulatory issues. The development of MRI-powered medical devices is an emerging field, but the potential clinical impact of these devices is promising.

  7. Portable MRI

    Energy Technology Data Exchange (ETDEWEB)

    Espy, Michelle A. [Los Alamos National Laboratory

    2012-06-29

    This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

  8. Metabolomics of Breast Cancer Using High-Resolution Magic Angle Spinning Magnetic Resonance Spectroscopy: Correlations with 18F-FDG Positron Emission Tomography-Computed Tomography, Dynamic Contrast-Enhanced and Diffusion-Weighted Imaging MRI.

    Directory of Open Access Journals (Sweden)

    Haesung Yoon

    Full Text Available Our goal in this study was to find correlations between breast cancer metabolites and conventional quantitative imaging parameters using high-resolution magic angle spinning (HR-MAS magnetic resonance spectroscopy (MRS and to find breast cancer subgroups that show high correlations between metabolites and imaging parameters.Between August 2010 and December 2013, we included 53 female patients (mean age 49.6 years; age range 32-75 years with a total of 53 breast lesions assessed by the Breast Imaging Reporting and Data System. They were enrolled under the following criteria: breast lesions larger than 1 cm in diameter which 1 were suspicious for malignancy on mammography or ultrasound (US, 2 were pathologically confirmed to be breast cancer with US-guided core-needle biopsy (CNB 3 underwent 3 Tesla MRI with dynamic contrast-enhanced (DCE and diffusion-weighted imaging (DWI and positron emission tomography-computed tomography (PET-CT, and 4 had an attainable immunohistochemistry profile from CNB. We acquired spectral data by HR-MAS MRS with CNB specimens and expressed the data as relative metabolite concentrations. We compared the metabolites with the signal enhancement ratio (SER, maximum standardized FDG uptake value (SUV max, apparent diffusion coefficient (ADC, and histopathologic prognostic factors for correlation. We calculated Spearman correlations and performed a partial least squares-discriminant analysis (PLS-DA to further classify patient groups into subgroups to find correlation differences between HR-MAS spectroscopic values and conventional imaging parameters.In a multivariate analysis, the PLS-DA models built with HR-MAS MRS metabolic profiles showed visible discrimination between high and low SER, SUV, and ADC. In luminal subtype breast cancer, compared to all cases, high SER, ADV, and SUV were more closely clustered by visual assessment. Multiple metabolites were correlated with SER and SUV in all cases. Multiple metabolites

  9. MRI Safety during Pregnancy

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z MRI Safety During Pregnancy Magnetic resonance imaging (MRI) Illness ... during the exam? Contrast material MRI during pregnancy Magnetic resonance imaging (MRI) If you are pregnant and your doctor ...

  10. Breast MRI scan

    Science.gov (United States)

    MRI - breast; Magnetic resonance imaging - breast; Breast cancer - MRI; Breast cancer screening - MRI ... radiologist) see some areas more clearly. During the MRI, the person who operates the machine will watch ...

  11. MRI (Magnetic Resonance Imaging)

    Science.gov (United States)

    ... and Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... usually given through an IV in the arm. MRI Research Programs at FDA Magnetic Resonance Imaging (MRI) ...

  12. MRI of central nervous system anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Izawa, M.; Oikawa, A.; Matoba, A.

    1987-05-01

    MRI was very useful in the evaluation of congenital anomalies of central nervous system as well as other nervous system disease with three-dimensional spatial resolution. We had experienced MRI of central nervous system anomalies, demonstrated characterisitic findings in each anomaly. MRI is useful to observe the coronal, horizontal and sagittal images of the brain and spinal cord in order to discuss the etiological mechanisms of spinal dysraphysm and its associated anomalies. In case of spina bifida cystica MRI was available to decide operative indication for radical operation and tetherd cord developed from postoperative scar or accompanied intraspinal lesions.

  13. Cystic angiomatosis with splenic involvement: unusual MRI findings

    Energy Technology Data Exchange (ETDEWEB)

    Vanhoenacker, F.M. [Dept. of Radiology, Univ. Hospital Antwerp, Edegem (Belgium); Dept. of Radiology, AZ St-Maarten, Campus Duffel, Duffel (Belgium); Schepper, A.M. [Dept. of Radiology, Univ. Hospital Antwerp, Edegem (Belgium); Raeve, H. [Dept. of Pathology, Univ. Hospital Antwerp, Edegem (Belgium); Berneman, Z. [Dept. of Hematology, Univ. Hospital Antwerp, Edegem (Belgium)

    2003-12-01

    Cystic angiomatosis is a rare disorder with a poor prognosis. We describe a case of a 33-year-old woman who presented with longstanding bone pain, hemolytic anemia, and an enlarged spleen. Radiologically, multiple osseous lesions with a mixed pattern of lytic and sclerotic areas were seen within the shoulders, spine, and pelvis. On CT and MRI of the abdomen, the spleen was markedly enlarged, with internal hyperdense foci on non-contrast CT scan, corresponding to low signal intensity areas on all MR pulse sequences. After administration of contrast, a mottled enhancement pattern throughout the entire spleen was seen both on CT and MRI. Cystic angiomatosis was proven by histological analysis of a biopsy specimen of an involved vertebra and histopathological examination of the spleen after subsequent splenectomy. This is the first report of a patient with disseminated cystic angiomatosis with splenic involvement in which the MRI features differ from the previous reports. Instead of the usual pattern consisting of multiple well-defined cystic lesions, a diffuse involvement replacing the entire spleen, with heterogeneous signal intensities on T2-weighted images and heterogeneous enhancement pattern, was seen in our patient. (orig.)

  14. The Performance of Noncontrast Magnetic Resonance Angiography in Detecting Renal Artery Stenosis as Compared With Contrast Enhanced Magnetic Resonance Angiography Using Conventional Angiography as a Reference.

    Science.gov (United States)

    Liang, Keng-Wei; Chen, Jhih-Wei; Huang, Hsin-Hui; Su, Chun-Hung; Tyan, Yeu-Sheng; Tsao, Teng-Fu

    The aims of this study were to evaluate the performance of noncontrast magnetic resonance angiography (NC MRA) for detecting renal artery stenosis (RAS) as compared with contrast-enhanced magnetic resonance angiography (CE MRA) and to evaluate the clinical feasibility, technical success rate, and performance of NC MRA for detecting RAS as compared with CE MRA. Thirty-six subjects who underwent NC MRA and/or CE MRA were enrolled. Feasibility, technical success rate, and image quality scores were compared. Diagnostic ability was calculated using conventional angiography as a reference. Noncontrast MRA had higher feasibility and technical success rates than CE MRA did (100% and 97.2% vs 83.3% and 90%, respectively). Noncontrast MRA yielded significantly better image quality in motion artifact (P = 0.016). The diagnostic ability for detecting RAS is without significant difference between NC MRA and CE MRA. Although NC MRA and CE MRA demonstrated comparable ability in diagnosing RAS, NC MRA achieved better technical success rates, feasibility, and image quality in motion artifacts than CE MRA did.

  15. Multiparametric Breast MRI of Breast Cancer

    Science.gov (United States)

    Rahbar, Habib; Partridge, Savannah C.

    2015-01-01

    Synopsis Breast MRI has increased in popularity over the past two decades due to evidence for its high sensitivity for cancer detection. Current clinical MRI approaches rely on the use of a dynamic contrast enhanced (DCE-MRI) acquisition that facilitates morphologic and semi-quantitative kinetic assessments of breast lesions. The use of more functional and quantitative parameters, such as pharmacokinetic features from high temporal resolution DCE-MRI, apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM) on diffusion weighted MRI, and choline concentrations on MR spectroscopy, hold promise to broaden the utility of MRI and improve its specificity. However, due to wide variations in approach among centers for measuring these parameters and the considerable technical challenges, robust multicenter data supporting their routine use is not yet available, limiting current applications of many of these tools to research purposes. PMID:26613883

  16. Automated segmentation of mammary gland regions in non-contrast torso CT images based on probabilistic atlas

    Science.gov (United States)

    Zhou, X.; Kan, M.; Hara, T.; Fujita, H.; Sugisaki, K.; Yokoyama, R.; Lee, G.; Hoshi, H.

    2007-03-01

    The identification of mammary gland regions is a necessary processing step during the anatomical structure recognition of human body and can be expected to provide the useful information for breast tumor diagnosis. This paper proposes a fully-automated scheme for segmenting the mammary gland regions in non-contrast torso CT images. This scheme calculates the probability for each voxel belonging to the mammary gland or other regions (for example pectoralis major muscles) in CT images and decides the mammary gland regions automatically. The probability is estimated from the location of the mammary gland and pectoralis major muscles in CT images. The location (named as a probabilistic atlas) is investigated from the pre-segmentation results in a number of different CT scans and the CT number distribution is approximated using a Gaussian function. We applied this scheme to 66 patient cases (female, age: 40-80) and evaluated the accuracy by using the coincidence rate between the segmented result and gold standard that is generated manually by a radiologist for each CT case. The mean value of the coincidence rate was 0.82 with the standard deviation of 0.09 for 66 CT cases.

  17. Comparison between ultrasound and noncontrast helical computed tomography for identification of acute ureterolithiasis in a teaching hospital setting

    Directory of Open Access Journals (Sweden)

    Luís Ronan Marquez Ferreira de Souza

    2007-03-01

    Full Text Available CONTEXT AND OBJECTIVE: Recent studies have shown noncontrast computed tomography (NCT to be more effective than ultrasound (US for imaging acute ureterolithiasis. However, to our knowledge, there are few studies directly comparing these techniques in an emergency teaching hospital setting. The objectives of this study were to compare the diagnostic accuracy of US and NCT performed by senior radiology residents for diagnosing acute ureterolithiasis; and to assess interobserver agreement on tomography interpretations by residents and experienced abdominal radiologists. DESIGN AND SETTING: Prospective study of 52 consecutive patients, who underwent both US and NCT within an interval of eight hours, at Hospital São Paulo. METHODS: US scans were performed by senior residents and read by experienced radiologists. NCT scan images were read by senior residents, and subsequently by three abdominal radiologists. The interobserver variability was assessed using the kappa statistic. RESULTS: Ureteral calculi were found in 40 out of 52 patients (77%. US presented sensitivity of 22% and specificity of 100%. When collecting system dilatation was associated, US demonstrated 73% sensitivity, 82% specificity. The interobserver agreement in NCT analysis was very high with regard to identification of calculi, collecting system dilatation and stranding of perinephric fat. CONCLUSIONS: US has limited value for identifying ureteral calculi in comparison with NCT, even when collecting system dilatation is present. Residents and abdominal radiologists demonstrated excellent agreement rates for ureteral calculi, identification of collecting system dilatation and stranding of perinephric fat on NCT.

  18. Quantitative breast MRI radiomics for cancer risk assessment and the monitoring of high-risk populations

    Science.gov (United States)

    Mendel, Kayla R.; Li, Hui; Giger, Maryellen L.

    2016-03-01

    Breast density is routinely assessed qualitatively in screening mammography. However, it is challenging to quantitatively determine a 3D density from a 2D image such as a mammogram. Furthermore, dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) is used more frequently in the screening of high-risk populations. The purpose of our study is to segment parenchyma and to quantitatively determine volumetric breast density on pre-contrast axial DCE-MRI images (i.e., non-contrast) using a semi-automated quantitative approach. In this study, we retroactively examined 3D DCE-MRI images taken for breast cancer screening of a high-risk population. We analyzed 66 cases with ages between 28 and 76 (mean 48.8, standard deviation 10.8). DCE-MRIs were obtained on a Philips 3.0 T scanner. Our semi-automated DCE-MRI algorithm includes: (a) segmentation of breast tissue from non-breast tissue using fuzzy cmeans clustering (b) separation of dense and fatty tissues using Otsu's method, and (c) calculation of volumetric density as the ratio of dense voxels to total breast voxels. We examined the relationship between pre-contrast DCE-MRI density and clinical BI-RADS density obtained from radiology reports, and obtained a statistically significant correlation [Spearman ρ-value of 0.66 (p < 0.0001)]. Our method within precision medicine may be useful for monitoring high-risk populations.

  19. MRI of the Chest

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Chest Magnetic resonance imaging (MRI) of the chest ... limitations of MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) is ...

  20. MRI of the Achilles tendon

    Energy Technology Data Exchange (ETDEWEB)

    Naegele, M.; Lienemann, A.; Hahn, D.; Lissner, J.; Boehm, P.

    1987-06-01

    The Achilles tendon and preachillar space of 30 patients was studied by MRI. A surface coil (Helmholtz' principle) was applied and all patients were examined with a superconducting magnet operating at 1.0 Tesla field strength. The purpose of the study was to illustrate pathological changes of the tendon and the surrounding soft tissue. In 3 cases MRI diagnosed a total rupture of the Achilles tendon. Furthermore, the strain of the tendon and side effects of an inflammatory process could be demonstrated. The use of a surface coil yields a high resolution of the normal anatomy of the region and of the pathological changes of the tendon and the surrounding soft tissue structures. The advantages of MRI for Achilles tendon diagnostics against competitive modalities are 1) excellent soft tissue contrast, 2) multiplanar imaging, 3) as well as exact delineation and visualisation of the lesion.

  1. The potential of multiparametric MRI of the breast

    Science.gov (United States)

    Pinker, Katja; Helbich, Thomas H

    2017-01-01

    MRI is an essential tool in breast imaging, with multiple established indications. Dynamic contrast-enhanced MRI (DCE-MRI) is the backbone of any breast MRI protocol and has an excellent sensitivity and good specificity for breast cancer diagnosis. DCE-MRI provides high-resolution morphological information, as well as some functional information about neoangiogenesis as a tumour-specific feature. To overcome limitations in specificity, several other functional MRI parameters have been investigated and the application of these combined parameters is defined as multiparametric MRI (mpMRI) of the breast. MpMRI of the breast can be performed at different field strengths (1.5–7 T) and includes both established (diffusion-weighted imaging, MR spectroscopic imaging) and novel MRI parameters (sodium imaging, chemical exchange saturation transfer imaging, blood oxygen level-dependent MRI), as well as hybrid imaging with positron emission tomography (PET)/MRI and different radiotracers. Available data suggest that multiparametric imaging using different functional MRI and PET parameters can provide detailed information about the underlying oncogenic processes of cancer development and progression and can provide additional specificity. This article will review the current and emerging functional parameters for mpMRI of the breast for improved diagnostic accuracy in breast cancer. PMID:27805423

  2. Rapid Response: To Scan or Not to Scan? The Utility of Noncontrast CT Head for Altered Mental Status.

    Science.gov (United States)

    Thacker, Purujit J; Sethi, Mansha; Sternlieb, Jonathan; Schneider, Doron; Naglak, Mary; Patel, Rajeshkumar R

    2018-01-17

    The aims of the study were the following: (1) to determine how often computed tomography (CT) scans of the head are obtained on rapid responses called for altered mental status (AMS), (2) to determine whether CT imaging of the head is required during all rapid responses called for AMS, (3) to determine which patients would benefit from CT scans of the head in this setting, (4) to note whether an adequate neurologic exam was documented, (5) to determine the cost of CT scans that did not change management, and (6) to examine the role of medications leading to AMS. The study was a retrospective chart review at Abington Jefferson Hospital. Data collected included the age, sex, time of rapid response, clinical condition of the patient, whether an arterial blood gas and blood glucose were done, and whether a neurological exam was documented in the resident's rapid response team note. The patient's medications were also reviewed. Computed tomography scan findings as well as changes made in a patient's care as a result of the scan were recorded. Any findings that did not lead to a change in management were considered a "negative" scan. Overall, 610 rapid responses were activated from January to August 2016. One hundred four (17.04%) of the total rapid responses were for AMS and 83 (79.8%) of these patients underwent noncontrast CT scan of the head. The mean (SD) age of the patients was 74.7 (13.6) years. A total of 56.6% were female. The most frequent clinical conditions documented at the time of rapid responses were noted as confused (33.7%, 28/83), either lethargic or unconscious (32.5%, 27/83), and concern for stroke (21.7%, 18/83). A total of 96.4% (80/83) of the CT scans done were negative for any acute changes. The three patients with positive scans (3/83) had a change in management as a result of the scans. If patients with symptoms concerning for stroke and unconscious patients are excluded, the total number of remaining patients is 56. Of these, zero patients had

  3. MRI of the Chest

    Medline Plus

    Full Text Available ... as chest x-ray or CT. A special form of MRI called magnetic resonance angiography (MRA) is ... not to have an MRI exam during the first trimester unless medically necessary. MRI may not always ...

  4. MRI of the Chest

    Medline Plus

    Full Text Available ... or patients with claustrophobia. Other MRI machines are open on the sides (open MRI). Open units are especially helpful for examining larger patients or those with claustrophobia. Newer open MRI units provide very high quality images for ...

  5. MRI of the Chest

    Medline Plus

    Full Text Available ... the limitations of MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) is a noninvasive ... top of page What are some common uses of the procedure? MR imaging of the chest is ...

  6. MRI of the Chest

    Medline Plus

    Full Text Available ... in the first three to four months of pregnancy unless the potential benefit from the MRI exam ... the MRI Safety page for more information about pregnancy and MRI. If you have claustrophobia (fear of ...

  7. MRI of the Chest

    Medline Plus

    Full Text Available ... MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) is a noninvasive ... of page What are some common uses of the procedure? MR imaging of the chest is performed ...

  8. Risk Stratification of Thyroid Incidentalomas Found on PET/CT: The Value of Iodine Content on Noncontrast Computed Tomography.

    Science.gov (United States)

    Kim, Dongwoo; Hwang, Sang Hyun; Cha, Jongtae; Jo, Kwanhyeong; Lee, Narae; Yun, Mijin

    2015-11-01

    The Hounsfield unit (HU) ratio of thyroid nodules was assessed compared to the contralateral thyroid lobe on noncontrast computed tomography (CT) to stratify further the risk of malignancy in thyroid incidentalomas found on 18F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/CT (PET/CT). This retrospective analysis included 82 patients who had thyroid incidentalomas on PET/CT in 2011. On PET/CT, the maximal standardized uptake value ratios of the thyroid nodule compared to liver (T/BSUV) and the HU ratios of the thyroid nodule compared to contralateral thyroid lobe (T/BHU) were calculated. Diagnostic performances of the T/BSUV and T/BHU were compared. The area under the curve of T/BHU was higher than that of T/BSUV (0.941 vs. 0.689, p risk of malignancy was much higher (71.1%) in nodules with a T/BHU cutoff value ≤0.68, whereas it was 0% in nodules with a T/BHU of >0.68. In this study, there were 18 nodules with nondiagnostic (n = 7) or atypia of undetermined significance or follicular lesion of undetermined significance cytologies (n = 11) after fine-needle aspiration biopsy (FNAB). When the T/BHU cutoff value was applied, three (60%) of the five nodules with a T/BHU of ≤0.68 were found to be papillary carcinomas. The remaining 13 nodules with a T/BHU of >0.68 were all benign with a risk of malignancy of 0%. T/BHU is a simple and effective parameter to stratify the risk of malignancy in thyroid incidentalomas found on PET/CT. This may be of clinical relevance in those nodules with nondiagnostic or undetermined significance cytologies upon FNAB in the scheme of current clinical practice.

  9. Evaluation of Azygous Vein Aneurysm Using Integrated PET/MRI

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Hyo Jung; Kang, Keon Wook; Lee, Dong Soo; Goo, Jin Mo; Kim, Young Tae; Park, Young Sik; Cheon, Gi Jeong [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    2014-06-15

    A previously healthy, non-smoking, 72-year-old woman was referred to our hospital with abnormal chest X-ray and chest discomfort. A 3.5-cm, well-defined, right paratracheal mass was revealed on non-contrast chest computed tomography (CT), which was suspected to be an azygous vein aneurysm, lymph adenopathy or neurogenic tumor. Whole-body integrated positron emission tomography/magnetic resonance imaging (PET/MRI) (Biograph mMR; Siemens Healthcare, Erlangen, Germany) was performed for the differential diagnosis. A homogenously enhancing mass connected with the azygous vein was well visualized in a post-contrast volumetric interpolated gradient echo (VIBE) sequence. Additionally, the PET showed minimal {sup 18}F-fluorodeoxyglucose (FDG) uptake (maximum standardized uptake value [SUVmax], 1.83), similar to that of the great vessels, with no filling defect to suggest thromboembolism and no significant FDG uptake to suggest active thrombo-embolism or malignancy. The imaging findings in integrated PET/MRI were useful to characterize azygous vein aneurysm. The patient had a video-assisted thoracoscopic surgery to relieve the symptom of chest pain. A congenital etiology of azygous vein aneurysm was confirmed by pathology.

  10. Whole-body MRI screening

    Energy Technology Data Exchange (ETDEWEB)

    Puls, Ralf [HELIOS Klinikum Erfurt (Germany). Inst. of Diagnostic and Interventional Radiology and Neuroradiology; Hosten, Norbert (ed.) [Universitaetsklinikum Greifswald (Germany). Diagnostic Radiology and Neuroradiology

    2014-07-01

    The advent of dedicated whole-body MRI scanners has made it possible to image the human body from head to toe with excellent spatial resolution and with the sensitivity and specificity of conventional MR systems. A comprehensive screening examination by MRI relies on fast image acquisition, and this is now feasible owing to several very recent developments, including multichannel techniques, new surface coil systems, and automatic table movement. The daily analysis of whole-body MRI datasets uncovers many incidental findings, which are discussed by an interdisciplinary advisory board of physicians from all specialties. This book provides a systematic overview of these incidental findings with the aid of approximately 240 high-quality images. The radiologists involved in the project have written chapters on each organ system, presenting a structured compilation of the most common findings, their morphologic appearances on whole-body MRI, and guidance on their clinical management. Chapters on technical and ethical issues are also included. It is hoped that this book will assist other diagnosticians in deciding how to handle the most common incidental findings encountered when performing whole-body MRI.

  11. Automated assessment of breast tissue density in non-contrast 3D CT images without image segmentation based on a deep CNN

    Science.gov (United States)

    Zhou, Xiangrong; Kano, Takuya; Koyasu, Hiromi; Li, Shuo; Zhou, Xinxin; Hara, Takeshi; Matsuo, Masayuki; Fujita, Hiroshi

    2017-03-01

    This paper describes a novel approach for the automatic assessment of breast density in non-contrast three-dimensional computed tomography (3D CT) images. The proposed approach trains and uses a deep convolutional neural network (CNN) from scratch to classify breast tissue density directly from CT images without segmenting the anatomical structures, which creates a bottleneck in conventional approaches. Our scheme determines breast density in a 3D breast region by decomposing the 3D region into several radial 2D-sections from the nipple, and measuring the distribution of breast tissue densities on each 2D section from different orientations. The whole scheme is designed as a compact network without the need for post-processing and provides high robustness and computational efficiency in clinical settings. We applied this scheme to a dataset of 463 non-contrast CT scans obtained from 30- to 45-year-old-women in Japan. The density of breast tissue in each CT scan was assigned to one of four categories (glandular tissue within the breast 75%) by a radiologist as ground truth. We used 405 CT scans for training a deep CNN and the remaining 58 CT scans for testing the performance. The experimental results demonstrated that the findings of the proposed approach and those of the radiologist were the same in 72% of the CT scans among the training samples and 76% among the testing samples. These results demonstrate the potential use of deep CNN for assessing breast tissue density in non-contrast 3D CT images.

  12. Animal MRI Core

    Data.gov (United States)

    Federal Laboratory Consortium — The Animal Magnetic Resonance Imaging (MRI) Core develops and optimizes MRI methods for cardiovascular imaging of mice and rats. The Core provides imaging expertise,...

  13. MRI anatomy of anteriorly displaced anus: what obstructs defecation?

    Energy Technology Data Exchange (ETDEWEB)

    AbouZeid, Amr Abdelhamid [Ain-Shams University, Department of Pediatric Surgery, Cairo (Egypt); Mohammad, Shaimaa Abdelsattar; Khairy, Khaled Talaat [Ain-Shams University, Department of Radiodiagnosis, Cairo (Egypt)

    2014-07-15

    Anteriorly displaced anus is an anomaly that is debated with regard to its nomenclature, diagnosis and management. To describe MRI anatomy of the anal canal in children with anteriorly displaced anus and its impact on the process of defecation. We prospectively examined ten children (7 girls, 3 boys; age range 7 months to 8 years, mean 3 years) with anteriorly displaced anus between August 2009 and April 2012. Noncontrast MRI examinations were performed on a 1.5-T magnet. T1- and T2-weighted turbo spin-echo images were acquired in axial, sagittal and coronal planes of the pelvis. The anorectal angle and the relative hiatal distance were measured in mid-sagittal images, and compared with those of a control group using the Mann-Whitney test. In children with anteriorly displaced anus, no anatomical abnormality was depicted at the level of the proximal anal canal. However, the distal anal canal was displaced anteriorly, running out its external muscle cuff, which remained un-displaced at the usual site of the anus. This changes the orientation of the central axis of the anal canal by passing across instead of along the fibers of the longitudinal muscle coat. Children with anteriorly displaced anus had a more obtuse anorectal angle (mean 112.1 ), which was significantly greater than that of the control group (mean 86.2 ). MRI is a valuable tool in studying the anatomy of the anal canal in children with anteriorly displaced anus. The abnormal orientation of the longitudinal muscle across the anal canal can explain the obstructed defecation in these children. Based on this study, it might be of interest to use MRI in studying equivocal cases and children with unexplained constipation. (orig.)

  14. Non-contrast CT at comparable dose to an abdominal radiograph in patients with acute renal colic; impact of iterative reconstruction on image quality and diagnostic performance

    OpenAIRE

    McLaughlin, P. D.; Murphy, K. P.; Hayes, S.A; Carey, K; Sammon, J.; Crush, L.; O’Neill, F.; Normoyle, B.; McGarrigle, A. M.; Barry, J E; Maher, M. M.

    2014-01-01

    Objectives The aim was to assess the performance of low-dose non-contrast CT of the urinary tract (LD-CT) acquired at radiation exposures close to that of abdominal radiography using adaptive statistical iterative reconstruction (ASiR). Methods Thirty-three patients with clinically suspected renal colic were prospectively included. Conventional dose (CD-CT) and LD-CT data sets were contemporaneously acquired. LD-CT images were reconstructed with 40 %, 70 % and 90 % ASiR. Image quality was sub...

  15. Magnetic Resonance Imaging (MRI) Safety

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how does it ... and MRI Breast-feeding and MRI What is MRI and how does it work? Magnetic resonance imaging, ...

  16. Magnetic Resonance Imaging (MRI) -- Head

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head ... limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is ...

  17. MRI of the Musculoskeletal System

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Musculoskeletal Magnetic resonance imaging (MRI) uses a powerful ... the limitations of a Musculoskeletal MRI? What is MRI of the Musculoskeletal System? Magnetic resonance imaging (MRI) ...

  18. Magnetic Resonance Imaging (MRI) - Spine

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Spine Magnetic resonance imaging (MRI) of the spine ... limitations of MRI of the Spine? What is MRI of the Spine? Magnetic resonance imaging (MRI) is ...

  19. Evaluation of small internal mammary lymph node metastases in breast cancer by MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, Takahiro; Sugimura, Kazuro; Shiotani, Seiji [Shimane Medical Univ., Izumo (Japan); Odagiri, Kunio; Andoh, Kazuo; Doiuchi, Tsunehiro; Asaga, Taro

    1999-05-01

    In breast cancer, diagnosis of a small internal mammary lymph node (IMLN) metastasis of less than 10 mm in size has been difficult. Our purpose was to retrospectively evaluate MRI findings of small IMLN metastases in comparison with dissected IMLNs. We studied 43 dissected IMLNs (range 2-12 mm, mean 4.512{+-}2.763 mm) in 16 women with breast cancer (15 primary, and 1 recurrent). MRI examinations were performed using a 1.5 Tesla scanner (200FX; Toshiba, Tokyo, Japan) to obtain noncontrast T1-weighted SE images (TR/TE; 500/15 or 400/15 ms), with a slice thickness of 5 mm on coronal images, 10 mm or 7 mm on sagittal images, FOV 15 x 15 cm, matrix 256 x 256, using a surface coil with patients in the supine position. MR images were evaluated regarding the major diameter and shape and margin of each node. Regarding the presence of IMLN metastases, there was a significant difference between nodes with a major diameter of 5 mm or more and those of less than 5 mm (p<0.05). Using the size-based criterion (defining {<=}5 mm as positive), MRI had 90.7% accuracy, 93.3% sensitivity, and 89.3% specificity. There were no significant differences in the shape-or margin-based criterion. MRI was useful in diagnosing small IMLN metastases, using a size-based criterion. (author)

  20. MRI of the Chest

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Chest Magnetic resonance imaging (MRI) of the chest uses a powerful ... Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  1. Diagnostic accuracy of virtual non-contrast enhanced dual-energy CT for diagnosis of adrenal adenoma: A systematic review and meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Connolly, Michael J.; McInnes, Matthew D.F.; Schieda, Nicola [University of Ottawa Department of Radiology, Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON (United States); El-Khodary, Mohamed [McMaster University Department of Radiology, Hamilton, ON (Canada); McGrath, Trevor A. [University of Ottawa, Faculty of Medicine, Ottawa, Ontario (Canada)

    2017-10-15

    To compare the diagnostic accuracy of dual-energy (DE) virtual non-contrast computed tomography (vNCT) to non-contrast CT (NCT) for the diagnosis of adrenal adenomas. Search of multiple databases and grey literature was performed. Two reviewers independently applied inclusion criteria and extracted data. Risk of bias was assessed using QUADAS-2. Summary estimates of diagnostic accuracy were generated and sources of heterogeneity were assessed. Five studies (170 patients; 192 adrenal masses) were included for diagnostic accuracy assessment; all used dual-source dual-energy CT. Pooled sensitivity for adrenal adenoma on vNCT was 54% (95% CI: 47-62%). Pooled sensitivity for NCT was 57% (95% CI: 45-69%). Pooling of specificity was not performed since no false positives were reported. There was a trend for overestimation of HU density on vNCT as compared to NCT which appeared related to contrast timing. Potential sources of bias were seen regarding the index test and reference standard for the included studies. Potential sources of heterogeneity between studies were seen in adenoma prevalence and intravenous contrast timing. vNCT images generated from dual-energy CT demonstrated comparable sensitivity to NCT for the diagnosis of adenomas; however the included studies are heterogeneous and at high risk for some types of bias. (orig.)

  2. Quantitative Rapid Assessment of Leukoaraiosis in CT : Comparison to Gold Standard MRI.

    Science.gov (United States)

    Hanning, Uta; Sporns, Peter Bernhard; Schmidt, Rene; Niederstadt, Thomas; Minnerup, Jens; Bier, Georg; Knecht, Stefan; Kemmling, André

    2017-10-20

    The severity of white matter lesions (WML) is a risk factor of hemorrhage and predictor of clinical outcome after ischemic stroke; however, in contrast to magnetic resonance imaging (MRI) reliable quantification for this surrogate marker is limited for computed tomography (CT), the leading stroke imaging technique. We aimed to present and evaluate a CT-based automated rater-independent method for quantification of microangiopathic white matter changes. Patients with suspected minor stroke (National Institutes of Health Stroke scale, NIHSS < 4) were screened for the analysis of non-contrast computerized tomography (NCCT) at admission and compared to follow-up MRI. The MRI-based WML volume and visual Fazekas scores were assessed as the gold standard reference. We employed a recently published probabilistic brain segmentation algorithm for CT images to determine the tissue-specific density of WM space. All voxel-wise densities were quantified in WM space and weighted according to partial probabilistic WM content. The resulting mean weighted density of WM space in NCCT, the surrogate of WML, was correlated with reference to MRI-based WML parameters. The process of CT-based tissue-specific segmentation was reliable in 79 cases with varying severity of microangiopathy. Voxel-wise weighted density within WM spaces showed a noticeable correlation (r = -0.65) with MRI-based WML volume. Particularly in patients with moderate or severe lesion load according to the visual Fazekas score the algorithm provided reliable prediction of MRI-based WML volume. Automated observer-independent quantification of voxel-wise WM density in CT significantly correlates with microangiopathic WM disease in gold standard MRI. This rapid surrogate of white matter lesion load in CT may support objective WML assessment and therapeutic decision-making during acute stroke triage.

  3. EPOXI MARS OBS - MRI RAW IMAGES V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains raw 750-nm filter images of Mars acquired by the Deep Impact Medium Resolution Visible CCD (MRI) for the EPOCh project during the second...

  4. EPOXI MARS OBS - MRI CALIBRATED IMAGES V2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset contains calibrated 750-nm filter images of Mars acquired by the Deep Impact Medium Resolution Visible CCD (MRI) for the EPOCh project during the second...

  5. EPOXI EARTH OBS - MRI CALIBRATED IMAGES V2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset contains calibrated, 750-nm filter images of Earth acquired by the Deep Impact Medium Resolution Visible CCD (MRI) during the EPOCh and Cruise 2 phases...

  6. EPOXI INFLIGHT CALIBRATIONS - MRI RAW IMAGES V2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset contains raw calibration images acquired by the Medium Resolution Visible CCD (MRI) from 04 October 2007 through 28 November 2010 during the EPOCh,...

  7. EPOXI MARS OBS - MRI CALIBRATED IMAGES V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains calibrated 750-nm filter images of Mars acquired by the Deep Impact Medium Resolution Visible CCD (MRI) for the EPOCh project during the...

  8. Epoxi Inflight Calibrations - MRI Raw Images V2.0

    Science.gov (United States)

    McLaughlin, S. A.; Carcich, B.; Sackett, S. E.; Klaasen, K. P.; Wellnitz, D. D.

    2012-01-01

    This dataset contains raw calibration images acquired by the Medium Resolution Visible CCD (MRI) from 04 October 2007 through 28 November 2010 during the EPOCh, 103P/Hartley 2 Encounter, and cruise phases of the EPOXI mission.

  9. Accuracy of Noncontrast Quiescent-Interval Single-Shot Lower Extremity MR Angiography Versus CT Angiography for Diagnosis of Peripheral Artery Disease Comparison With Digital Subtraction Angiography : Comparison With Digital Subtraction Angiography

    NARCIS (Netherlands)

    Varga-Szemes, Akos; Wichmann, Julian L; Schoepf, U Joseph; Suranyi, Pal; De Cecco, Carlo N; Muscogiuri, Giuseppe; Caruso, Damiano; Yamada, Ricardo T; Litwin, Sheldon E; Tesche, Christian; Duguay, Taylor M; Giri, Shivraman; Vliegenthart, Rozemarijn; Todoran, Thomas M

    2017-01-01

    OBJECTIVES This study sought to evaluate the image quality and diagnostic accuracy of noncontrast quiescent-interval single-shot (QISS) magnetic resonance angiography (MRA) versus iodine-contrast computed tomography angiography (CTA) in patients with peripheral artery disease (PAD), with invasive

  10. A 4-channel 3 Tesla phased array receive coil for awake rhesus monkey fMRI and diffusion MRI experiments.

    Science.gov (United States)

    Khachaturian, Mark Haig

    2010-01-01

    Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments are performed with single coils which suffer from severe EPI distortions which limit resolution. By constructing phased array coils for monkey MRI studies, gains in SNR and anatomical accuracy (i.e., reduction of EPI distortions) can be achieved using parallel imaging. The major challenges associated with constructing phased array coils for monkeys are the variation in head size and space constraints. Here, we apply phased array technology to a 4-channel phased array coil capable of improving the resolution and image quality of full brain awake monkey fMRI and diffusion MRI experiments. The phased array coil is that can adapt to different rhesus monkey head sizes (ages 4-8) and fits in the limited space provided by monkey stereotactic equipment and provides SNR gains in primary visual cortex and anatomical accuracy in conjunction with parallel imaging and improves resolution in fMRI experiments by a factor of 2 (1.25 mm to 1.0 mm isotropic) and diffusion MRI experiments by a factor of 4 (1.5 mm to 0.9 mm isotropic).

  11. Synthetic MRI for visualization of quantitative MRI

    OpenAIRE

    Peterson, Erika

    2013-01-01

    Magnetic resonance imaging (MRI) is an imaging technique that is used in hospitals worldwide. The images are acquired through the use of an MRI scanner and the clinical information is provided through the image contrast, which is based on the magnetic properties in biological tissue. By altering the scanner settings, images with different contrast properties can be obtained. Conventional MRI is a qualitative imaging technique and no absolute measurements are performed. At Center for Medical I...

  12. Accuracy of MRI in Growth Plate Measurement

    DEFF Research Database (Denmark)

    Shiguetomi Medina, Juan Manuel; Rahbek, Ole; Ringgaard, Steffen

    2013-01-01

    was measured and compared to histology. Results. Histology measurements showed a mean growth plate thickness of 467 μm (SD = 82.2). The mean growth plate thickness measured in the 7T MR images was 465 μm (SD = 62.2) and 1325 μm (SD=183.5) on 1.5 MRI measurements. We found a better correlation between...... the growth plate thickness measured on the 7T MRI and histology samples compared to 1.5T, where the accuracy was poor. Conclusion. The growth plate can be identified and measured with high accuracy using 7T MRI. 1.5T MRI can only describe some morphological characteristics; its poor resolution impedes to do...

  13. Optimizing MRI of small joints and extremities.

    Science.gov (United States)

    Thomas, M S; Greenwood, R; Nolan, C; Malcolm, P N; Toms, A P

    2014-10-01

    Obtaining optimal images of small joints using magnetic resonance imaging (MRI) can be technically challenging. The aim of this review is to outline the practical aspects of MRI of small joints, with reference to the underlying physical principles. Although the most important contribution to successful imaging of small joints comes from the magnet field strength and design of the receiver coil, there are a number of factors to balance including the signal-to-noise ratio, image resolution, and acquisition times. We discuss strategies to minimize artefacts from movement, inhomogeneity, chemical shift, and fat suppression. As with all MRI, each strategy comes at a price, but the benefits and costs of each approach can be fine-tuned to each combination of joint, receiver coil, and MRI machine. Copyright © 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  14. Laminar fMRI : What can the time domain tell us?

    NARCIS (Netherlands)

    Petridou, Natalia; Siero, Jeroen C W

    The rapid developments in functional MRI (fMRI) acquisition methods and hardware technologies in recent years, particularly at high field (≥7 T), have enabled unparalleled visualization of functional detail at a laminar or columnar level, bringing fMRI close to the intrinsic resolution of brain

  15. Association of epicardial adipose tissue and left atrial size on non-contrast CT with atrial fibrillation: the Heinz Nixdorf Recall Study.

    Science.gov (United States)

    Mahabadi, Amir A; Lehmann, Nils; Kälsch, Hagen; Bauer, Marcus; Dykun, Iryna; Kara, Kaffer; Moebus, Susanne; Jöckel, Karl-Heinz; Erbel, Raimund; Möhlenkamp, Stefan

    2014-08-01

    Epicardial adipose tissue (EAT) is increased in subjects with atrial fibrillation (AF). Likewise, EAT is associated with left atrial (LA) size, as itself is a strong predictor of AF. We aimed to determine the association of EAT and LA size as computed tomography (CT)-derived measures with prevalent and incident AF and investigated whether both measures independently predict AF. Participants from the Heinz Nixdorf Recall study without known cardiovascular disease were included. At baseline, EAT, defined as fat volume inside the pericardial sac, and LA size, defined as an axial area at the level of the mitral valve, were quantified from non-contrast enhanced cardiac CT. AF was determined from electrocardiogram at baseline and also at 5-year follow-up examination. Overall, 3467 participants (age: 58.9 ± 7.6 years, 47% male) were included. Ninety-six subjects had AF (46 prevalent and 50 incident). A 1-standard deviation (SD) change of EAT was associated with nearly two-fold increased prevalence of AF in univariate analysis, which persisted after adjustment for AF risk factors [odds ratio (OR) (95% confidence interval, 95% CI): 1.38 (1.11-1.72), P = 0.003]. Ancillary adjusting for LA reduced the effect [1.26 (0.996-1.60), P = 0.054]. For incident AF, no relevant effect was observed for EAT when adjusting for risk factors [1.19 (0.88-1.61), P = 0.26]. In contrast, a 1-SD chance of LA was strongly associated with AF independently of EAT and risk factors [2.70 (2.22-2.20), P < 0.0001]. LA but not EAT as non-contrast CT-derived measures improved the prediction of AF over risk factors (receiver operating characteristics: 0.810-0.845, P = 0.025). LA size from non-contrast CT is strongly associated with prevalent and incident AF and ultimately diminishes the link of EAT with AF. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  16. Soil - Plant - Atmosphere continuum studies by MRI

    NARCIS (Netherlands)

    As, van H.; Homan, N.; Vergeldt, F.J.

    2012-01-01

    Understanding the way in which plants develop, grow, and interact with their environment requires tools capable of a high degree of both spatial and temporal resolution. Here we present an overview of noninvasive intact plant MRI, which is not a straight forward extension of the methods discussed

  17. Biphosphonate-induced osteonecrosis of the jaws: CT and MRI spectrum of findings in 32 patients

    Energy Technology Data Exchange (ETDEWEB)

    Bisdas, S. [Department of Diagnostic and Interventional Radiology, Johann Wolfgang GoeUniversity Hospital, Frankfurt (Germany)], E-mail: sbisdas@yahoo.com; Chambron Pinho, N.; Smolarz, A.; Sader, R. [Department of Dentomaxillofacial and Plastic Surgery, Johann Wolfgang GoeUniversity Hospital, Frankfurt (Germany); Vogl, T.J.; Mack, M.G. [Department of Diagnostic and Interventional Radiology, Johann Wolfgang GoeUniversity Hospital, Frankfurt (Germany)

    2008-01-15

    Aim: To evaluate the computed tomography (CT) and magnetic resonance imaging (MRI) findings of biphosphonate therapy-associated changes of the mandible and maxilla. Materials and Methods: Thirty-two patients with a clinical history of pain, purulent discharge, and swelling in the mandible or maxilla as well as non-healing dental extraction were examined. All patients had received biphosphonate medication for approximately 33 months. Non-contrast enhanced CT and contrast-enhanced MRI were performed and, subsequently, all patients underwent a surgical removal of the affected bone, the histological diagnosis of which confirmed osteonecrosis. The images were read by two head and neck radiologists in consensus. Results: Osteonecrosis with Actinomyces infection was identified in the mandible of 18 patients, in the maxilla of eight patients, and in both jaws in six patients. The CT images showed predominantly osteolytic lesions and sclerotic regions in the jaws with or without periostal bone proliferation. There was a reduction of the marrow space in the jaws. The T1-weighted MRI signal was hypointense in nearly all cases. The gadolinium-enhanced MRI images revealed intensity changes of the cortical and subcortical bone structures in all patients. The T2-weighted MRI signal was hypointense on the affected side in the majority of the cases (28/32). Pathological gadolinium enhancement was observed in the neighbouring soft tissues, including the masticator space in all patients. Reactive lymphadenopathy was found in all patients in submental and jugulodigastric areas. Conclusion: Biphosphonate-induced osteonecrosis of the jaws presents a wide variety of CT and MRI features that are readily recognized and help to determine the extent of the disease; however, they are not specific for the disease.

  18. Magnetic Resonance Lithography with Nanometer Resolution

    Directory of Open Access Journals (Sweden)

    Fahad AlGhannam

    2016-04-01

    Full Text Available We propose an approach for super-resolution optical lithography which is based on the inverse of magnetic resonance imaging (MRI. The technique uses atomic coherence in an ensemble of spin systems whose final state population can be optically detected. In principle, our method is capable of producing arbitrary one and two dimensional high-resolution patterns with high contrast.

  19. Canalis basilaris medianus: MRI

    Energy Technology Data Exchange (ETDEWEB)

    Jacquemin, C. [Dept. of Radiology, King Khaled Eye Specialist Hospital, Riyadh (Saudi Arabia); Bosley, T.M.; Al Saleh, M. [Div. of Neuro-ophthalmology, King Khaled Eye Specialist Hospital, Riyadh (Saudi Arabia); Mullaney, P. [Division of Pediatrics, King Khaled Eye Specialist Hospital, Riyadh (Saudi Arabia)

    2000-02-01

    We report the MRI appearances of an developmental anatomical variant of the basiocciput, with neuroimaging findings (CT and MRI). Such variants are commonly asymptomatic, but may be associated with episodes of meningitis. (orig.)

  20. MRI of the Chest

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    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Chest Magnetic resonance imaging (MRI) of the chest uses a powerful magnetic field, radio waves and a computer to produce ...

  1. Abdominal MRI scan

    Science.gov (United States)

    Nuclear magnetic resonance - abdomen; NMR - abdomen; Magnetic resonance imaging - abdomen; MRI of the abdomen ... radiologist see certain areas more clearly. During the MRI, the person who operates the machine will watch ...

  2. MRI of the Chest

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    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... may not fit into the opening of certain types of MRI machines. The presence of an implant ...

  3. MRI of the Chest

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    Full Text Available ... treatment. See the MRI Safety page for more information about pregnancy and MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your physician for ...

  4. MRI of the Chest

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    Full Text Available ... a very small chance of irritation of your skin at the site of the IV tube insertion. ... detail makes MRI an invaluable tool in early diagnosis and evaluation of cardiovascular conditions. MRI has proven ...

  5. MRI of the Chest

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    Full Text Available ... to a CD or uploaded to a digital cloud server. MRI of the chest gives detailed pictures ... as chest x-ray or CT. A special form of MRI called magnetic resonance angiography (MRA) is ...

  6. MRI of the Chest

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    Full Text Available ... MRI scan. Because they can interfere with the magnetic field of the MRI unit, metal and electronic items ... and braces usually are not affected by the magnetic field, but they may distort images of the facial ...

  7. MRI of the Chest

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    Full Text Available ... eyes or other reactions. If you experience allergic symptoms, notify the technologist. A radiologist or other physician ... detail makes MRI an invaluable tool in early diagnosis and evaluation of cardiovascular conditions. MRI has proven ...

  8. MRI of the Chest

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    Full Text Available ... interfere with the magnetic field of the MRI unit, metal and electronic items are not allowed in ... does the equipment look like? The traditional MRI unit is a large cylinder-shaped tube surrounded by ...

  9. MRI of the Chest

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits MRI is a noninvasive imaging technique that ... risking the side effects of conventional (catheter) angiography . Risks The MRI examination poses almost no risk to ...

  10. MRI of the Chest

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    Full Text Available ... detail makes MRI an invaluable tool in early diagnosis and evaluation of cardiovascular conditions. MRI has proven ... the technologist or nurse will monitor your vital signs to minimize this risk. Although the strong magnetic ...

  11. MRI of the Chest

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    Full Text Available ... metallic items, which can distort MRI images removable dental work pens, pocket knives and eyeglasses body piercings In most cases, an MRI exam is safe for patients with metal implants, except for a few types. ...

  12. MRI of the Chest

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    Full Text Available ... other internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians ... computed tomography (CT) scans, MRI does not utilize ionizing radiation. Instead, radiofrequency pulses re-align hydrogen atoms ...

  13. MRI of the Chest

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    Full Text Available ... are the limitations of MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging ( ... heart, valves, great vessels, etc.). top of page What are some common uses of the procedure? MR ...

  14. MRI of the Chest

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    Full Text Available ... examination poses almost no risk to the average patient when appropriate safety guidelines are followed. If sedation is used, there ... patient story here Images × ... Resonance Imaging (MRI) Safety MRI Safety During Pregnancy Images related to Magnetic ...

  15. MRI of the Chest

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    Full Text Available ... women should not have this exam in the first three to four months of pregnancy unless the ... not to have an MRI exam during the first trimester unless medically necessary. MRI may not always ...

  16. MRI of the Chest

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    Full Text Available ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ... MRI an invaluable tool in early diagnosis and evaluation of cardiovascular conditions. MRI has proven valuable in ...

  17. MRI of the Chest

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    Full Text Available ... clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in ... might be obscured by bone with other imaging methods. The contrast material used in MRI exams is ...

  18. MRI of the Chest

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    Full Text Available ... devices require a short period of time after placement (usually six weeks) before being safe for MRI ... devices that contain metal may malfunction or cause problems during an MRI exam. Nephrogenic systemic fibrosis is ...

  19. MRI of the Chest

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    Full Text Available ... or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played ... the limitations of MRI of the Chest? High-quality images are assured only if you are able ...

  20. MRI of the Chest

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    Full Text Available ... contrast for an MRI. If you have a history of kidney disease or liver transplant, it will ... MRI. For more information, consult your radiologist. The computer workstation that processes the imaging information is located ...

  1. MRI of the Chest

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    Full Text Available ... internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to ... tomography (CT) scans, MRI does not utilize ionizing radiation. Instead, radiofrequency pulses re-align hydrogen atoms that ...

  2. MRI of the Chest

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    Full Text Available ... conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures ... does not completely surround you. Some newer MRI machines have a larger diameter bore which can be ...

  3. MRI of the Chest

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    Full Text Available ... contrast for an MRI. If you have a history of kidney disease or liver transplant, it will ... information on the chemicals present in the body's cells, may also be performed during the MRI exam ...

  4. 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.)

  5. Comparison of contrast and noncontrast magnetic resonance angiography for quantitative analysis of thoracic arteries in young patients with congenital heart defects

    Directory of Open Access Journals (Sweden)

    Pasqua Alessia

    2011-01-01

    Full Text Available Background : Contrast MRA (C-MRA is the standard for quantitative analysis of thoracic vessels. We evaluated a noncontrast MRA (NC-MRA sequence (3-D EKG and navigator-gated SSFP for quantitative evaluation of the thoracic aorta and branch pulmonary arteries in young patients with congenital heart disease. Objective : To compare contrast and noncontrast magnetic resonance angiography for quantitative analysis of thoracic arteries in young patients with congenital heart defects. Methods : Measurements of thoracic aorta and branch pulmonary arteries were obtained from C-MRA and NC-MRA images in 51 patients, ages 2-35 years. Vessel diameters were compared using correlation and Bland-Altman analysis. Interobserver variability was assessed using percent variation. Results : C-MRA and NC-MRA measurements were highly correlated (r = 0.91-0.98 except for the right pulmonary artery (r = 0.74, 0.78. Agreement of measurements was excellent (mean difference -0.07 to -0.53 mm; mean % difference -1.8 to -4.9% except for the right pulmonary artery which was less good (mean difference 0.73, -1.38 mm; -3, -10%. Interobserver variability ranged from 5% to 8% for aortic and from 10% to 16% for pulmonary artery measures. The worse agreement and greater variability of the pulmonary artery measures appears due to difficulty standardizing the measurements in patients with abnormal and irregular vessels. Conclusion : These data indicate that C-MRA and NC-MRA measures are comparable and could be used interchangeably, avoiding administration of contrast in selected patients.

  6. fMRI Neuroinformatics

    DEFF Research Database (Denmark)

    Nielsen, Finn Årup; Christensen, Mark Schram; Madsen, Kristoffer M.

    2006-01-01

    Functional magnetic resonance imaging (fMRI) generates vast amounts of data. The handling, processing, and analysis of fMRI data would be inconceivable without computer-based methods. fMRI neuroinformatics is concerned with research, development, and operation of these methods. Reconstruction...

  7. MRI of the Chest

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    Full Text Available ... or CT. A special form of MRI called magnetic resonance angiography (MRA) is helpful to assess the vessels of ... child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance Imaging (MRI) Safety MRI Safety During Pregnancy Images ...

  8. MRI of Cerebellar Infarction

    NARCIS (Netherlands)

    De Cocker, Laurens J L; Lövblad, Karl-Olof; Hendrikse, Jeroen

    2017-01-01

    BACKGROUND: MRI is the imaging modality of choice for diagnosing brain infarction. Because of few or atypical clinical symptoms and a relatively low sensitivity of CT scans, many cerebellar infarctions may be detected only with MRI. With adequate recognition of cerebellar infarction on MRI and

  9. MRI of the Chest

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    Full Text Available ... MRI exam is assumed to outweigh the potential risks. Pregnant women should not receive injections of gadolinium contrast material except when absolutely necessary for medical treatment. See the MRI Safety page for more information about pregnancy and MRI. If you have claustrophobia ( ...

  10. MRI of the Chest

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    Full Text Available ... are the limitations of MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) is a noninvasive ... heart, valves, great vessels, etc.). top of page What are some common uses of the procedure? MR ...

  11. MRI in acute poliomyelitis

    Energy Technology Data Exchange (ETDEWEB)

    Kornreich, L. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Dagan, O. [The Intensive Care Unit, The Schneider Children`s Medical Centre of Israel, Beilinson Medical Campus, Petah Tiqva (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Grunebaum, M. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel)

    1996-05-01

    MRI can be used in the diagnosis of anterior horn infection and for assessing the extent of disease. There are no specific MRI signs to differentiate between the various possible pathogens. This is demonstrated in the present case of poliomyelitis, in which MRI of the spine played an important role in establishing the diagnosis. (orig.). With 1 fig.

  12. MRI of the Chest

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    Full Text Available ... tumors. MRI can help physicians evaluate both the structure of an organ and how it is working. MRI enables the discovery of abnormalities that might be obscured by bone with other imaging methods. The contrast material used in MRI exams is less likely to ...

  13. SU-F-P-26: Study of Radiation Dose Evaluation for Organs at Risk Using MRI in Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Gong, G; Guo, Y; Yin, Y [Shandong Cancer Hospital and Institute, Jinan, Shandong (China)

    2016-06-15

    Purpose: To study the contour and dosimetric feature of organs at risk (OARs) applying magnetic resonance imaging (MRI) images in intensity modulated radiation therapy (IMRT) of nasopharyngeal carcinoma (NPC) compared to computed tomography (CT) images. Methods: 35 NPC patients was selected into this trail. CT simulation with non-contrast and contrast enhanced scan, MRI simulation with non-contrast and contrast enhanced T1, T2 and diffusion weighted imaging were achieved sequentially. And the OARs were contoured on the CT and MRI images after rigid registration respectively. 9 beams IMRT plan with equal division angle were designed for every patients, and the prescription dose for tumor target was set as 72Gy (2.4Gy/ fration). The boundary display, volume and dose-volume indices of each organ were compared between on MRI and CT images. Results: Compared to CT, MRI showed clearer boundary of brainstem, spinal cord, the deep lobe of Parotid gland and the optical nerve in canal. MRI images increase the volume of lens, optical nerve, while reducing the volume of eye slightly, and the maximum dose of lens, the mean dose of eyes and optical raised in different percentage, while there was no statistical differences were found. The left and right parotid volume on MRI increased by 7.07%, 8.13%, and the mean dose raised by 14.95% (4.01Gy), 18.76% (4.95Gy) with statistical significant difference (p<0.05). The brainstem volume reduced by 9.33% (p<0.05), and the dose of 0.1cm3 volume (D0.1cm3) reduced by mean 8.46% (4.32Gy), and D0.1cm3 of spinal cord increased by 1.5Gy on MRI. Conclusion: It is credible to evaluate the radiation dose of lens, eye and the spinal cord, while it should be necessary to evaluate the dose of brainstem, parotid and the optical nerve applying MRI images sometime, it will be more meaningful for these organs with high risk of radiation injury.

  14. Magnetic resonance imaging techniques: fMRI, DWI, and PWI.

    Science.gov (United States)

    Holdsworth, Samantha J; Bammer, Roland

    2008-09-01

    Magnetic resonance imaging (MRI) is a noninvasive technique which can acquire important quantitative and anatomical information from an individual in any plane or volume at comparatively high resolution. Over the past several years, developments in scanner hardware and software have enabled the acquisition of fast MRI imaging, proving extremely useful in various clinical and research applications such as in brain mapping or functional MRI (fMRI), perfusion-weighted imaging (PWI), and diffusion-weighted imaging (DWI). These techniques have revolutionized the use of MRI in the clinics, providing great insight into physiologic mechanisms and pathologic conditions. Since these relatively new areas of MRI have relied on fast scanning techniques, they have only recently been widely introduced to clinical sites. As such, this review article is devoted to the technological aspects of these techniques, as well as their roles and limitations in neuroimaging applications.

  15. Dental MRI using wireless intraoral coils

    Science.gov (United States)

    Ludwig, Ute; Eisenbeiss, Anne-Katrin; Scheifele, Christian; Nelson, Katja; Bock, Michael; Hennig, Jürgen; von Elverfeldt, Dominik; Herdt, Olga; Flügge, Tabea; Hövener, Jan-Bernd

    2016-03-01

    Currently, the gold standard for dental imaging is projection radiography or cone-beam computed tomography (CBCT). These methods are fast and cost-efficient, but exhibit poor soft tissue contrast and expose the patient to ionizing radiation (X-rays). The need for an alternative imaging modality e.g. for soft tissue management has stimulated a rising interest in dental magnetic resonance imaging (MRI) which provides superior soft tissue contrast. Compared to X-ray imaging, however, so far the spatial resolution of MRI is lower and the scan time is longer. In this contribution, we describe wireless, inductively-coupled intraoral coils whose local sensitivity enables high resolution MRI of dental soft tissue. In comparison to CBCT, a similar image quality with complementary contrast was obtained ex vivo. In-vivo, a voxel size of the order of 250•250•500 μm3 was achieved in 4 min only. Compared to dental MRI acquired with clinical equipment, the quality of the images was superior in the sensitive volume of the coils and is expected to improve the planning of interventions and monitoring thereafter. This method may enable a more accurate dental diagnosis and avoid unnecessary interventions, improving patient welfare and bringing MRI a step closer to becoming a radiation-free alternative for dental imaging.

  16. High-resolution MRI for the quantitative evaluation of subendocardial and subepicardial perfusion under pharmalogical stress and at rest; Hochaufgeloeste quantitative MR-tomografische Bestimmung der subendo- und subepimyokardialen Perfusion unter Stress und in Ruhe

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, C.O.; Savio, K. del; Brackertz, A.; Beer, M.; Hahn, D.; Koestler, H. [Wuerzburg Univ. (Germany). Inst. fuer Roentgendiagnostik

    2007-09-15

    Purpose: MR stress perfusion imaging of the heart allows the quantification of myocardial perfusion and the evaluation of myocardial perfusion reserve (MPR) and the ratio of subendocardial to subepicardial perfusion at rest and under adenosine stress. The aim of this study was to evaluate a high-resolution GRAPPA sequence for quantitative MR first pass perfusion imaging in healthy volunteers. Materials and Methods: First pass stress and rest perfusion studies were performed on 10 healthy volunteers using a 1.5 T MR scanner with a multislice SR-TrueFISP first pass perfusion sequence with a GRAPPA algorithm (acceleration factor 3) in prebolus technique and an image resolution of 1.8 x 1.8 mm. For the comparison group, we examined 12 different healthy volunteers with a standard first pass perfusion SR-TrueFISP sequence using a resolution of 2.7 x 3.3 mm. Myocardial contours were manually delineated followed by an automatic division of the myocardium into two rings with an equal thickness for the subendo- and subepicardial layer. Eight sectors per slice were evaluated using contamination and baseline correction. Results: Using the GRAPPA sequence, the ratio of subendo- to subepimyocardial perfusion was 1.18 {+-} 0.32 for the examination at rest. Under pharmacologically induced stress, the ratio was 1.08 {+-} 0.27. For the standard sequence the ratio was 1.15 {+-} 0.28 at rest and 1.11 {+-} 0.33 under stress. For the high resolution sequence higher mean values for the subendo- to subepimyocardial ratio were obtained with comparable standard deviations. The difference between the sequences was not significant. Conclusion: The evaluation of subendomyocardial and subepimyocardial perfusion is feasible with a high-resolution first pass perfusion sequence. The use of a higher resolution to avoid systematic error leads to increased image noise. However, no relevant reduction in the quantitative perfusion values under stress and at rest was able to be depicted. (orig.)

  17. Whole brain, high resolution multiband spin-echo EPI fMRI at 7 T: a comparison with gradient-echo EPI using a color-word Stroop task

    NARCIS (Netherlands)

    Boyacioglu, R.; Schulz, J.; Müller, N.C.J.; Koopmans, P.J.; Barth, M.; Norris, D.G.

    2014-01-01

    A whole brain, multiband spin-echo (SE) echo planar imaging (EPI) sequence employing a high spatial (1.5 mm isotropic) and temporal (TR of 2 s) resolution was implemented at 7 T. Its overall performance (tSNR, sensitivity and CNR) was assessed and compared to a geometrically matched gradient-echo

  18. Whole brain, high resolution multiband spin-echo EPI fMRI at 7 T: A comparison with gradient-echo EPI using a color-word Stroop task

    NARCIS (Netherlands)

    Boyacioglu, R.; Schulz, J.; Müller, N.C.J.; Koopmans, P.J.; Barth, M.; Norris, David Gordon

    2014-01-01

    A whole brain, multiband spin-echo (SE) echo planar imaging (EPI) sequence employing a high spatial (1.5 mm isotropic) and temporal (TR of 2 s) resolution was implemented at 7 T. Its overall performance (tSNR, sensitivity and CNR) was assessed and compared to a geometrically matched gradient-echo

  19. Predictive MRI correlates of lesser metatarsophalangeal joint plantar plate tear

    Energy Technology Data Exchange (ETDEWEB)

    Umans, Rachel L. [Cornell University Medical College, New York, NY (United States); Umans, Benjamin D. [Harvard University, Cambridge, MA (United States); Umans, Hilary [Albert Einstein College of Medicine, Bronx, NY (United States); Lenox Hill Radiology and Imaging Associates, New York, NY (United States); Elsinger, Elisabeth [Albert Einstein College of Medicine, Bronx, NY (United States); Montefiore Medical Center, Bronx, NY (United States)

    2016-07-15

    To identify correlated signs on non-enhanced MRI that might improve diagnostic detection of plantar plate (PP) tear. We performed an IRB-approved, HIPAA-compliant retrospective analysis of 100 non-contrast MRI (50 PP tear, 50 controls). All were anonymized, randomized, and reviewed; 20 were duplicated to assess consistency. One musculoskeletal radiologist evaluated qualitative variables. A trained non-physician performed measurements. Consistency and concordance were assessed. Pearson's Chi-square test was used to test the correlation between qualitative findings and PP tear status. Correlation between measurements and PP status was assessed using t tests and Wilcoxon's rank-sum test (p values < 0.05 considered significant). Classification and regression trees were utilized to identify attributes that, taken together, would consistently distinguish PP tear from controls. Quantitative measurements were highly reproducible (concordance 0.88-0.99). Elevated 2nd MT protrusion, lesser MT supination and rotational divergence of >45 between the 1st-2nd MT axis correlated with PP tear. Pericapsular soft tissue thickening correlated most strongly with PP tear, correctly classifying 95 % of cases and controls. Excluding pericapsular soft tissue thickening, sequential assessment of 2nd toe enthesitis, 2nd flexor tendon subluxation, and splaying of the second and third toes accurately classified PP status in 92 %. Pericapsular soft tissue thickening most strongly correlated with PP tear. For cases in which it might be difficult to distinguish pericapsular fibrosis from neuroma, sequential assessment of 2nd toe enthesitis, flexor tendon subluxation and splaying of the 2nd and 3rd toe is most helpful for optimizing accurate diagnosis of PP tear. (orig.)

  20. MRI in psychiatry

    Energy Technology Data Exchange (ETDEWEB)

    Mulert, Christoph [UKE, Hamburg (Germany). Psychiatry Neuroimaging Branch; Shenton, Martha E. (ed.) [Harvard Medical School, Boston, MA (United States). Dept. of Psychiatry and Radiology

    2014-07-01

    This is the first comprehensive textbook on the use of MRI in psychiatry covering imaging techniques, brain systems and a review of findings in different psychiatric disorders. The book is divided into three sections, the first of which covers in detail all the major MRI-based methodological approaches available today, including fMRI, EEG-fMRI, DTI, and MR spectroscopy. In addition, the role of MRI in imaging genetics and combined brain stimulation and imaging is carefully explained. The second section provides an overview of the different brain systems that are relevant for psychiatric disorders, including the systems for perception, emotion, cognition, and reward. The final part of the book presents the MRI findings that are obtained in all the major psychiatric disorders using the previously discussed techniques. Numerous carefully chosen images support the informative text, making this an ideal reference work for all practitioners and trainees with an interest in this flourishing field.

  1. Interactive near-real-time high-resolution imaging for MR-guided lumbar interventions using ZOOM imaging in an open 1.0 Tesla MRI system--initial experience.

    Science.gov (United States)

    Makowski, Marcus R; Jonczyk, Martin; Streitparth, Florian; Guettler, Felix; Rathke, Hendrik; Suttmeyer, Britta; Albrecht, Liane; Teichgräber, Ulf K; Hamm, Bernd; de Bucourt, Maximilian

    2015-12-01

    Different techniques for magnetic resonance-guided lumbar interventions have been introduced in recent years. Appropriate pulse sequence design is crucial since high spatial resolution often comes at the cost of lower temporal resolution. The purpose of this study was to evaluate the value of accelerated reduced field of view (ZOOM)-based imaging sequences for lumbar interventions. ZOOM imaging was used in 31 interventions (periradicular, facet joint, epidural infiltrations, and discography) performed in 24 patients (10 women, 14 men; age 43 ± 13.3 years). Signal-to-noise ratio and contrast-to-noise ratio (CNR) were determined and retrospectively compared with standard preinterventional (T2 weighted), peri-interventional (proton density), and postinterventional (spectral presaturation with inversion recovery [SPIR]) imaging. Needle artifacts were assessed by direct measurement as well as with parallel and perpendicular needle profiles. Puncture times were compared to similar interventions previously performed in our department. No significant differences in signal intensities (standard/ZOOM: 152.0/151.6; p=0.136) and CNR values (2.0/4.0; p=0.487) were identified for T2-weighted sequences. The needle artifact signal intensity was comparable (648.1/747.5; p=0.172) for peri-interventional imaging. Standard interventional (fat needle: 43.8/23.4; p228.5 s; p=0.026). ZOOM imaging is a feasible interactive sequence for lumbar interventions. It ameliorates the tradeoff between image quality and temporal resolution. Moreover, the sequence design reduces intervention times significantly.

  2. Some Renal Masses Did Not “Read the Book”: A Case of a High Grade Hybrid Renal Tumor Masquerading as a Renal Cyst on Non-contrast Imaging

    Directory of Open Access Journals (Sweden)

    Hal D. Kominsky

    2015-11-01

    Full Text Available Hybrid renal tumors (HRT are rare neoplasms that contain both benign and malignant components. Sporadic solitary HRT that contain high-grade malignant pathology appear to be extremely rare [1]. We describe a case at our institution of a tumor that was characterized as a type-2 papillary RCC and atypical oncocytoma hybrid that mimicked a simple cyst on non-contrast computed tomography.

  3. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head ... limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is ...

  4. Performance of today’s dual energy CT and future multi energy CT in virtual non-contrast imaging and in iodine quantification: A simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Faby, Sebastian, E-mail: sebastian.faby@dkfz.de; Kuchenbecker, Stefan; Sawall, Stefan; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120 (Germany); Simons, David; Schlemmer, Heinz-Peter [Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120 (Germany); Lell, Michael [Department of Radiology, University of Erlangen-Nürnberg, Maximiliansplatz 1, Erlangen 91054 (Germany)

    2015-07-15

    Purpose: To study the performance of different dual energy computed tomography (DECT) techniques, which are available today, and future multi energy CT (MECT) employing novel photon counting detectors in an image-based material decomposition task. Methods: The material decomposition performance of different energy-resolved CT acquisition techniques is assessed and compared in a simulation study of virtual non-contrast imaging and iodine quantification. The material-specific images are obtained via a statistically optimal image-based material decomposition. A projection-based maximum likelihood approach was used for comparison with the authors’ image-based method. The different dedicated dual energy CT techniques are simulated employing realistic noise models and x-ray spectra. The authors compare dual source DECT with fast kV switching DECT and the dual layer sandwich detector DECT approach. Subsequent scanning and a subtraction method are studied as well. Further, the authors benchmark future MECT with novel photon counting detectors in a dedicated DECT application against the performance of today’s DECT using a realistic model. Additionally, possible dual source concepts employing photon counting detectors are studied. Results: The DECT comparison study shows that dual source DECT has the best performance, followed by the fast kV switching technique and the sandwich detector approach. Comparing DECT with future MECT, the authors found noticeable material image quality improvements for an ideal photon counting detector; however, a realistic detector model with multiple energy bins predicts a performance on the level of dual source DECT at 100 kV/Sn 140 kV. Employing photon counting detectors in dual source concepts can improve the performance again above the level of a single realistic photon counting detector and also above the level of dual source DECT. Conclusions: Substantial differences in the performance of today’s DECT approaches were found for the

  5. Performance of today's dual energy CT and future multi energy CT in virtual non-contrast imaging and in iodine quantification: A simulation study.

    Science.gov (United States)

    Faby, Sebastian; Kuchenbecker, Stefan; Sawall, Stefan; Simons, David; Schlemmer, Heinz-Peter; Lell, Michael; Kachelrieß, Marc

    2015-07-01

    To study the performance of different dual energy computed tomography (DECT) techniques, which are available today, and future multi energy CT (MECT) employing novel photon counting detectors in an image-based material decomposition task. The material decomposition performance of different energy-resolved CT acquisition techniques is assessed and compared in a simulation study of virtual non-contrast imaging and iodine quantification. The material-specific images are obtained via a statistically optimal image-based material decomposition. A projection-based maximum likelihood approach was used for comparison with the authors' image-based method. The different dedicated dual energy CT techniques are simulated employing realistic noise models and x-ray spectra. The authors compare dual source DECT with fast kV switching DECT and the dual layer sandwich detector DECT approach. Subsequent scanning and a subtraction method are studied as well. Further, the authors benchmark future MECT with novel photon counting detectors in a dedicated DECT application against the performance of today's DECT using a realistic model. Additionally, possible dual source concepts employing photon counting detectors are studied. The DECT comparison study shows that dual source DECT has the best performance, followed by the fast kV switching technique and the sandwich detector approach. Comparing DECT with future MECT, the authors found noticeable material image quality improvements for an ideal photon counting detector; however, a realistic detector model with multiple energy bins predicts a performance on the level of dual source DECT at 100 kV/Sn 140 kV. Employing photon counting detectors in dual source concepts can improve the performance again above the level of a single realistic photon counting detector and also above the level of dual source DECT. Substantial differences in the performance of today's DECT approaches were found for the application of virtual non-contrast and iodine

  6. [Neurofunctional MRI at high magnetic fields].

    Science.gov (United States)

    Speck, O; Turner, R

    2013-05-01

    Functional magnetic resonance imaging (fMRI) examinations are limited in their sensitivity due to the low activation-induced signal change. Within short tolerable scan times the spatial resolution is thus limited. fMRI is a reliable tool in neuroscience as well as for clinical applications such as presurgical mapping of brain function. The fMRI sensitivity improves greatly (more than linearly) with increasing magnetic field strengths. For many years this was the main driving force in the push towards higher field strengths, such as 7 T. The sensitivity gain is greatest for high spatial resolution and fMRI with very high sub-millimeter resolution becomes feasible. Current results demonstrate that the localization of the blood oxygenation level dependent (BOLD) signal is better than previously assumed. High-field fMRI not only allows quantitative improvements but also opens the way to new information content, such as columnar and layer-dependent functional structures of the cortex. This may pave the way for further information, e.g. the directionality of cortico-cortical connections; however, these possibilities also pose new challenges. New methods for processing such high resolution data are required which do not require spatial smoothing and preserve the high information content. Common spatial resolutions of 2-3 mm are still very well suited for examinations at 3 T where they benefit from the low signal void, lower geometrical distortion and reduced acoustic noise. To achieve higher resolution at 7 T parallel imaging and geometric distortion correction are essential and permit the best congruence with structural data. The echo time at 7 T should be adjusted to about 20-25 ms. Data processing for single subjects or patients should be performed with little or no smoothing to retain resolution. Group studies could achieve good correlation with local normalization. New methods for information extraction, such as multivariate pattern analysis may allow

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... about pregnancy and MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ...

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... or patients with claustrophobia. Other MRI machines are open on the sides (open MRI). Open units are especially helpful for examining larger patients or those with claustrophobia. Newer open MRI units provide very high quality images for ...

  9. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... the limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive ... top of page What are some common uses of the procedure? MR imaging of the head is ...

  10. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... in the first three to four months of pregnancy unless the potential benefit from the MRI exam ... the MRI Safety page for more information about pregnancy and MRI. If you have claustrophobia (fear of ...

  11. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive ... of page What are some common uses of the procedure? MR imaging of the head is performed ...

  12. Whole brain, high resolution multiband spin-echo EPI fMRI at 7 T: a comparison with gradient-echo EPI using a color-word Stroop task.

    Science.gov (United States)

    Boyacioğlu, Rasim; Schulz, Jenni; Müller, Nils C J; Koopmans, Peter J; Barth, Markus; Norris, David G

    2014-08-15

    A whole brain, multiband spin-echo (SE) echo planar imaging (EPI) sequence employing a high spatial (1.5 mm isotropic) and temporal (TR of 2 s) resolution was implemented at 7 T. Its overall performance (tSNR, sensitivity and CNR) was assessed and compared to a geometrically matched gradient-echo (GE) EPI multiband sequence (TR of 1.4 s) using a color-word Stroop task. PINS RF pulses were used for refocusing to reduce RF amplitude requirements and SAR, summed and phase-optimized standard pulses were used for excitation enabling a transverse or oblique slice orientation. The distortions were minimized with the use of parallel imaging in the phase encoding direction and a post-acquisition distortion correction. In general, GE-EPI shows higher efficiency and higher CNR in most brain areas except in some parts of the visual cortex and superior frontal pole at both the group and individual-subject levels. Gradient-echo EPI was able to detect robust activation near the air/tissue interfaces such as the orbito-frontal and subcortical regions due to reduced intra-voxel dephasing because of the thin slices used and high in-plane resolution. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Noninvasive electrical conductivity measurement by MRI: a test of its validity and the electrical conductivity characteristics of glioma.

    Science.gov (United States)

    Tha, Khin Khin; Katscher, Ulrich; Yamaguchi, Shigeru; Stehning, Christian; Terasaka, Shunsuke; Fujima, Noriyuki; Kudo, Kohsuke; Kazumata, Ken; Yamamoto, Toru; Van Cauteren, Marc; Shirato, Hiroki

    2018-01-01

    This study noninvasively examined the electrical conductivity (σ) characteristics of diffuse gliomas using MRI and tested its validity. MRI including a 3D steady-state free precession (3D SSFP) sequence was performed on 30 glioma patients. The σ maps were reconstructed from the phase images of the 3D SSFP sequence. The σ histogram metrics were extracted and compared among the contrast-enhanced (CET) and noncontrast-enhanced tumour components (NCET) and normal brain parenchyma (NP). Difference in tumour σ histogram metrics among tumour grades and correlation of σ metrics with tumour grades were tested. Validity of σ measurement using this technique was tested by correlating the mean tumour σ values measured using MRI with those measured ex vivo using a dielectric probe. Several σ histogram metrics of CET and NCET of diffuse gliomas were significantly higher than NP (Bonferroni-corrected p ≤ .045). The maximum σ of NCET showed a moderate positive correlation with tumour grade (r = .571, Bonferroni-corrected p = .018). The mean tumour σ measured using MRI showed a moderate positive correlation with the σ measured ex vivo (r = .518, p = .040). Tissue σ can be evaluated using MRI, incorporation of which may better characterise diffuse gliomas. • This study tested the validity of noninvasive electrical conductivity measurements by MRI. • This study also evaluated the electrical conductivity characteristics of diffuse glioma. • Gliomas have higher electrical conductivity values than the normal brain parenchyma. • Noninvasive electrical conductivity measurement can be helpful for better characterisation of glioma.

  14. MRI of the Chest

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. MRI ...

  15. MRI of the Chest

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    Full Text Available ... detail makes MRI an invaluable tool in early diagnosis and evaluation of cardiovascular conditions. MRI has proven ... in diagnosing a broad range of conditions, including cancer, heart and ... tissues, except for lung abnormalities where Chest CT is a preferred imaging ...

  16. MRI of the Chest

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    Full Text Available ... pediatric facilities have child life personnel who can work with younger children to help avoid the need for sedation or anesthesia. They prepare the children for MRI by showing them a dummy scanner, play the noises that the child might hear during the MRI ...

  17. MRI of the Chest

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    Full Text Available ... body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to evaluate various ... seen by other imaging modalities, such as chest x-ray or CT. A special form of MRI called ...

  18. MRI of the Chest

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    Full Text Available ... lesions seen by other imaging modalities, such as chest x-ray or CT. A special form of MRI called ... perform than other imaging modalities. MRI of the chest takes more time than an x-ray or CT exam. Because of the length of ...

  19. MRI of the Chest

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    Full Text Available ... zippers and similar metallic items, which can distort MRI images removable dental work pens, pocket knives and eyeglasses body piercings In ... scanner. top of page How does the procedure work? Unlike ... (CT) scans, MRI does not utilize ionizing radiation. Instead, radiofrequency pulses ...

  20. Cervical MRI scan

    Science.gov (United States)

    ... cancer in the spine Arthritis in the spine MRI works better than CT scan in diagnosing these problems ... test. The strong magnetic fields created during an MRI can cause heart pacemakers and other implants to not work as well. It can also cause a piece ...

  1. MRI of the Chest

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    Full Text Available ... Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us ... absolutely necessary for medical treatment. See the MRI Safety page for more information about pregnancy and MRI. ...

  2. MRI of the Chest

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    Full Text Available ... Whether a child requires sedation depends on the child's age, intellectual development and the type of exam. Moderate and conscious ... for MRI by showing them a dummy scanner, play the noises that the child might hear during the MRI exam, answer any ...

  3. MRI of the Chest

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    Full Text Available ... if a finding is stable or changed over time. top of page What are the benefits vs. risks? Benefits MRI is a ... resonance imaging harms the fetus, pregnant women usually are advised not to have ... may take more time to perform than other imaging modalities. MRI of ...

  4. MRI of the Chest

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    Full Text Available ... metallic items, which can distort MRI images removable dental work pens, pocket knives and eyeglasses body piercings In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the ...

  5. PET/MRI in Oncological Imaging: State of the Art

    Science.gov (United States)

    Bashir, Usman; Mallia, Andrew; Stirling, James; Joemon, John; MacKewn, Jane; Charles-Edwards, Geoff; Goh, Vicky; Cook, Gary J.

    2015-01-01

    Positron emission tomography (PET) combined with magnetic resonance imaging (MRI) is a hybrid technology which has recently gained interest as a potential cancer imaging tool. Compared with CT, MRI is advantageous due to its lack of ionizing radiation, superior soft-tissue contrast resolution, and wider range of acquisition sequences. Several studies have shown PET/MRI to be equivalent to PET/CT in most oncological applications, possibly superior in certain body parts, e.g., head and neck, pelvis, and in certain situations, e.g., cancer recurrence. This review will update the readers on recent advances in PET/MRI technology and review key literature, while highlighting the strengths and weaknesses of PET/MRI in cancer imaging. PMID:26854157

  6. Efficacy of ultrasound elastography in detecting active myositis in children: can it replace MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Berko, Netanel S.; Levin, Terry L. [Montefiore Medical Center, Department of Radiology, Bronx, NY (United States); Hay, Arielle [Montefiore Medical Center, Department of Pediatrics, Division of Pediatric Rheumatology, Bronx, NY (United States); Miami Children' s Hospital, Department of Pediatrics, Miami, FL (United States); Sterba, Yonit; Wahezi, Dawn [Montefiore Medical Center, Department of Pediatrics, Division of Pediatric Rheumatology, Bronx, NY (United States)

    2015-09-15

    Juvenile idiopathic inflammatory myopathy is a rare yet potentially debilitating condition. MRI is used both for diagnosis and to assess response to treatment. No study has evaluated the performance of US elastography in the diagnosis of this condition in children. To assess the performance of compression-strain US elastography in detecting active myositis in children with clinically confirmed juvenile idiopathic inflammatory myopathy and to compare its efficacy to MRI. Children with juvenile idiopathic inflammatory myopathy underwent non-contrast MR imaging as well as compression-strain US elastography of the quadriceps muscles. Imaging findings from both modalities were compared to each other as well as to the clinical determination of active disease based on physical examination and laboratory data. Active myositis on MR was defined as increased muscle signal on T2-weighted images. Elastography images were defined as normal or abnormal based on a previously published numerical scale of muscle elastography in normal children. Muscle echogenicity was graded as normal or abnormal based on gray-scale sonographic images. Twenty-one studies were conducted in 18 pediatric patients (15 female, 3 male; age range 3-19 years). Active myositis was present on MRI in ten cases. There was a significant association between abnormal MRI and clinically active disease (P = 0.012). US elastography was abnormal in 4 of 10 cases with abnormal MRI and in 4 of 11 cases with normal MRI. There was no association between abnormal elastography and either MRI (P > 0.999) or clinically active disease (P > 0.999). Muscle echogenicity was normal in 11 patients; all 11 had normal elastography. Of the ten patients with increased muscle echogenicity, eight had abnormal elastography. There was a significant association between muscle echogenicity and US elastography (P < 0.001). The positive and negative predictive values for elastography in the determination of active myositis were 75% and 31

  7. Coronary artery calcium score and the long-term risk of atrial fibrillation in patients undergoing non-contrast cardiac computed tomography for suspected coronary artery disease

    DEFF Research Database (Denmark)

    Vinter, Nicklas; Christesen, Amanda M S; Mortensen, Leif S

    2017-01-01

    Aims: To examine the association between coronary artery calcium score (CACS) and risk of future atrial fibrillation (AF), and to estimate the predictive accuracy of CACS for AF development in patients undergoing non-contrast cardiac computed tomography (nCCT). Methods and results: We conducted......CCT. We used Cox proportional hazards models to estimate hazard ratios (HR) with 95% confidence intervals (CI). A receiver operating characteristic (ROC) curve for AF was used to assess the predictive accuracy of CACS. Among the patients, 52% had a CACS of 0, 26% of 1-99, 13% of 100-399, 6% of 400.......33-2.35); and CACS ≥ 1000: 1.67 (1.20-2.34). An ROC curve showed an area under the curve of 0.68 (0.65-0.71) for the prediction of AF within one year after nCCT. Conclusion: A high CACS is associated with a high risk of subsequent AF development and may have potential to guide future follow-ups for AF detection...

  8. Randomized prospective comparison of non-contrast enhanced helical computed tomography and intravenous urography in the diagnosis of acute ureteric colic.

    Science.gov (United States)

    Homer, J A; Davies-Payne, D L; Peddinti, B S

    2001-08-01

    Non-contrast enhanced helical CT has become an accepted technique for evaluating acute ureteric colic. The results of a randomized prospective comparison of the accuracy, cost and radiation dose of CT and intravenous urography (IVU) are presented. All patients presenting to the Emergency Department with symptoms and signs suggestive of ureteric colic over a 16-month period (n = 242) were randomized to CT or IVU. Follow up was obtained for 228 patients (94%), with 14 patients (6%) lost to follow up. One hundred and twenty-three patients (54%) underwent CT and 105 (46%) had an IVU. At follow up the sensitivity and specificity of CT were each 100%, while those of IVU were 99% and 100%, respectively. Computed tomography demonstrated seven of 26 (27%) potential alternative diagnoses, whereas IVU suggested one of 23 (4%). Estimates of the average effective dose were calculated for CT (4.95 mSv) and IVU (1.48 mSv, 95% confidence interval (CI) 0.7-2.27). Radiation dose and intravenous contrast material safety are discussed and the relative costs are considered. Computed tomography is as accurate as IVU in the diagnosis of acute ureteric colic. It confers certain major diagnostic benefits, and is a fast, well-tolerated technique. Its accompanying higher effective radiation dose is recognized.

  9. MRI in acute disseminated encephalomyelitis following Semple antirabies vaccine

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, J.M.K. [Department of Neurology, Nizam`s Institute of Medical Sciences, Panjagutta, Hyderabad (India)

    1998-07-01

    I reviewed MRI findings in five patients with acute disseminated encephalomyelitis following vaccination with Semple antirabies vaccine. MRI in two patients with encephalitis features showed multiple white matter lesions in the cerebrum, cerebellar peduncles and brain stem. Two patients who had features of cord involvement showed signal alterations in the cord extending over a few segments. Asymptomatic lesions in the cerebrum were seen in two patients. In a patient with encephalomyelitis MRI 50 days later showed resolution of the lesions. The white matter lesions described were indistinguishable from those seen in acute disseminated encephalomyelitis following other infections. (orig.) With 3 figs., 1 tab., 26 refs.

  10. Resolution and super-resolution.

    Science.gov (United States)

    Sheppard, Colin J R

    2017-06-01

    Many papers have claimed the attainment of super-resolution, i.e. resolution beyond that achieved classically, by measurement of the profile of a feature in the image. We argue that measurement of the contrast of the image of a dark bar on a bright background does not give a measure of resolution, but of detection sensitivity. The width of a bar that gives an intensity at the center of the bar of 0.735 that in the bright region (the same ratio as in the Rayleigh resolution criterion) is λ/(13.9×numerical aperture) for the coherent case with central illumination. This figure, which compares with λ/(numerical aperture) for the Abbe resolution limit with central illumination, holds for the classical case, and so is no indication of super-resolution. Theoretical images for two points, two lines, arrays of lines, arrays of bars, and grating objects are compared. These results can be used a reference for experimental results, to determine if super-resolution has indeed been attained. The history of the development of the theory of microscope resolution is outlined. © 2017 Wiley Periodicals, Inc.

  11. Ultrasound- and MRI-Guided Prostate Biopsy

    Science.gov (United States)

    ... Resources Professions Site Index A-Z Ultrasound- and MRI-Guided Prostate Biopsy Ultrasound- and MRI-guided prostate ... MRI-guided Prostate Biopsy? What is Ultrasound- and MRI-guided Prostate Biopsy? Ultrasound- and MRI-guided prostate ...

  12. MRI of the Body (Chest, Abdomen, Pelvis)

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Body Magnetic resonance imaging (MRI) of the body ... limitations of MRI of the Body? What is MRI of the Body? Magnetic resonance imaging (MRI) is ...

  13. MRI/linac integration.

    Science.gov (United States)

    Lagendijk, Jan J W; Raaymakers, Bas W; Raaijmakers, Alexander J E; Overweg, Johan; Brown, Kevin J; Kerkhof, Ellen M; van der Put, Richard W; Hårdemark, Björn; van Vulpen, Marco; van der Heide, Uulke A

    2008-01-01

    In radiotherapy the healthy tissue involvement still poses serious dose limitations. This results in sub-optimal tumour dose and complications. Daily image guided radiotherapy (IGRT) is the key development in radiation oncology to solve this problem. MRI yields superb soft-tissue visualization and provides several imaging modalities for identification of movements, function and physiology. Integrating MRI functionality with an accelerator can make these capacities available for high precision, real time IGRT. The system being built at the University Medical Center Utrecht is a 1.5T MRI scanner, with diagnostic imaging functionality and quality, integrated with a 6MV radiotherapy accelerator. The realization of a prototype of this hybrid system is a joint effort between the Radiotherapy Department of the University of Utrecht, the Netherlands, Elekta, Crawley, U.K., and Philips Research, Hamburg, Germany. Basically, the design is a 1.5 T Philips Achieva MRI scanner with a Magnex closed bore magnet surrounded by a single energy (6 MV) Elekta accelerator. Monte Carlo simulations are used to investigate the radiation beam properties of the hybrid system, dosimetry equipment and for the construction of patient specific dose deposition kernels in the presence of a magnetic field. The latter are used to evaluate the IMRT capability of the integrated MRI linac. A prototype hybrid MRI/linac for on-line MRI guidance of radiotherapy (MRIgRT) is under construction. The aim of the system is to deliver the radiation dose with mm precision based on diagnostic quality MR images.

  14. Accuracy of Diffusion Weighted Images and MR Spectroscopy in Prostate Lesions - Our Experience with Endorectal Coil on 1.5 T MRI.

    Science.gov (United States)

    Jagannathan, Devimeenal; Indiran, Venkatraman

    2017-05-01

    Prostatic cancer is most commonly seen in individuals greater than 65 years of age. The incidence rates are constantly increasing. To assess the accuracy of the non-contrast sequences {Diffusion Weighted Imaging (DWI) and Magnetic Resonance Spectroscopy (MRS)} in the multiparametric Magnetic Resonance Imaging (mp-MRI) in identifying and differentiating benign and malignant prostate lesions using endorectal coil on 1.5 T MRI. Twenty-six patients with clinical indications for prostate lesions were evaluated using endorectal coil on 1.5 T MRI. DWI and MRS were obtained in all the lesions. Signal change on T2 weighted images, Apparent Diffusion Coefficient (ADC) values and choline + creatinine to citrate ratios (Cho+Cr/Ci) of the lesions were obtained for all the patients. All the patients underwent Transrectal Ultrasound (TRUS) guided biopsy within one week of MRI study. Signal change on T2 weighted images, DWI and Cho+Cr/Ci ratios were correlated with the histopathological findings using appropriate statistical analysis (Wilson score). Of the 26 patients, seven had benign pathology and 19 had malignant pathology on the histopathological examination. Sensitivity and specificity (89.5% and 85.7% respectively) of the diagnosis of malignancy based on DWI were quite good. Positive and negative predictive values were also very much acceptable (94.4% and 75% respectively). Though, MRS had good sensitivity and Positive Predictive Value (PPV) (84.2% and 76.2% respectively), specificity and Negative Predictive Value (NPV) were poor (28.6% and 40% respectively). Accuracy of imaging diagnosis based on combining T2, DWI and MRS was same as that of results based on T2 signal alone (80.8%) and had higher sensitivity and lower specificity than DWI alone (94.7% and 42.9% respectively). Receiver Operating Characteristic (ROC) curves were calculated for ADC values and Cho+Cr/Ci ratios. The Area Under the Curve (AUC) for ADC is 0.74 and for Cho+Cr/Ci is 0.70. Comparing the accuracy of

  15. MRI in sarcoglycanopathies

    DEFF Research Database (Denmark)

    Tasca, Giorgio; Monforte, Mauro; Díaz-Manera, Jordi

    2018-01-01

    OBJECTIVES: To characterise the pattern and spectrum of involvement on muscle MRI in a large cohort of patients with sarcoglycanopathies, which are limb-girdle muscular dystrophies (LGMD2C-2F) caused by mutations in one of the four genes coding for muscle sarcoglycans. METHODS: Lower limb MRI scans......, while lower leg muscles were relatively spared even in advanced disease. A proximodistal gradient of involvement of vasti muscles was a consistent finding in these patients, including the most severe ones. CONCLUSIONS: Muscle involvement on MRI is consistent in patients with LGMD2C-F and can be helpful...

  16. MRI of the optic nerve in benign intracranial hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Gass, A. [NMR Research Group, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London (United Kingdom); Barker, G.J. [NMR Research Group, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London (United Kingdom); Riordan-Eva, P. [Department of Neuro-Ophthalmology, National Hospital for Neurology and Neurosurgery, London (United Kingdom); MacManus, D. [NMR Research Group, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London (United Kingdom); Sanders, M. [Department of Neuro-Ophthalmology, National Hospital for Neurology and Neurosurgery, London (United Kingdom); Tofts, P.S. [NMR Research Group, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London (United Kingdom); McDonald, W.I. [NMR Research Group, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London (United Kingdom)]|[Moorfields Eye Hospital, London (United Kingdom); Moseley, I.F. [Lysholm Department of Radiology, National Hospital for Neurology and Neurosurgery, London (United Kingdom)]|[Moorfields Eye Hospital, London (United Kingdom); Miller, D.H. [NMR Research Group, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London (United Kingdom)

    1996-11-01

    We investigated the MRI appearance of the optic nerve and its cerebrospinal-fluid-containing sheath in 17 patients with benign intracranial hypertension (BIH) and 15 normal controls. Using phased-array local coils, 3-mm coronal T2-weighted fat-suppressed fast spin-echo images were obtained with an in-plane resolution of < 0.39 mm. The optic nerve and its sheath were clearly differentiated. An enlarged, elongated subarachnoid space around the optic nerve was demonstrated in patients with BIH. High-resolution MRI of the optic nerve offers additional information which may be of value for diagnosis and in planning and monitoring treatment. (orig.). With 5 figs.

  17. Brain MRI in Parkinson's disease

    NARCIS (Netherlands)

    Meijer, F.J.A.; Goraj, B.M.

    2014-01-01

    In this review article, conventional brain MRI and advanced MRI techniques in Parkinson`s disease (PD) are discussed, with emphasis on clinical relevance. Conventional brain MRI sequences generally demonstrate limited abnormalities specific for PD and in clinical practice brain MRI is mainly used to

  18. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  19. Elemental imaging of MRI contrast agents: benchmarking of LA-ICP-MS to MRI

    Energy Technology Data Exchange (ETDEWEB)

    Pugh, J.A.T. [University of Sheffield, Centre for Analytical Sciences, Sheffield (United Kingdom); University of Sheffield, Department of Chemical and Biological Engineering, Sheffield (United Kingdom); Cox, A.G.; McLeod, C.W. [University of Sheffield, Centre for Analytical Sciences, Sheffield (United Kingdom); Bunch, J. [University of Birmingham, School of Chemistry, Birmingham (United Kingdom); Writer, M.J.; Hart, S.L. [UCL Institute of Child Health, Wolfson Centre for Gene Therapy of Childhood Disease, London (United Kingdom); Bienemann, A.; White, E. [University of Bristol, School of Clinical Sciences, Southmead Hospital, Bristol (United Kingdom); Bell, J. [Hammersmith Hospital, Metabolic and Molecular Imaging Group, MRC Clinical Sciences Centre, Imperial College London, London (United Kingdom)

    2012-06-15

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been used to map the spatial distribution of magnetic resonance imaging (MRI) contrast agents (Gd-based) in histological sections in order to explore synergies with in vivo MRI. Images from respective techniques are presented for two separate studies namely (1) convection enhanced delivery of a Gd nanocomplex (developmental therapeutic) into rat brain and (2) convection enhanced delivery, with co-infusion of Magnevist (commercial Gd contrast agent) and Carboplatin (chemotherapy drug), into pig brain. The LA technique was shown to be a powerful compliment to MRI not only in offering improved sensitivity, spatial resolution and signal quantitation but also in giving added value regarding the fate of administered agents (Gd and Pt agents). Furthermore simultaneous measurement of Fe enabled assignment of an anomalous contrast enhancement region in rat brain to haemorrhage at the infusion site. (orig.)

  20. MRI of the Chest

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    Full Text Available ... any recent surgeries. Some conditions, such as severe kidney disease, may prevent you from being given gadolinium ... an MRI. If you have a history of kidney disease or liver transplant, it will be necessary ...

  1. MRI of the Chest

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    Full Text Available ... you should let the radiologist know about them. Parents or family members who accompany patients into the ... intercom. Many MRI centers allow a friend or parent to stay in the room as long as ...

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    Full Text Available ... patient to have an allergy to a gadolinium-based contrast agent used for MRI than the iodine- ... For more information on adverse reactions to gadolinium-based contrast agents, please consult the ACR Manual on ...

  5. MRI of the Chest

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    Full Text Available ... be removed. MRI exams generally include multiple runs (sequences), some of which may last several minutes. The ... You may be able to relax between imaging sequences, but will be asked to maintain your position ...

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  7. MRI of the Chest

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    Full Text Available ... you have a history of kidney disease or liver transplant, it will be necessary to perform a blood ... procedure work? Unlike conventional x-ray examinations and computed tomography (CT) scans, MRI does not utilize ionizing radiation. ...

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  10. MRI of the Chest

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    Full Text Available ... metallic items, which can distort MRI images removable dental work pens, pocket knives and eyeglasses body piercings ... from the contrast material, including nausea, headache and pain at the site of injection. Similarly, patients are ...

  11. MRI of the Chest

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    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... very rare occasions, a few patients experience side effects from the contrast material, including nausea, headache and ...

  12. MRI of the Chest

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    Full Text Available ... tissue and fluid, known as edema . MRI typically costs more and may take more time to perform ... accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, ...

  13. MRI of the Chest

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    Full Text Available ... period is necessary. You may resume your usual activities and normal diet immediately after the exam. On ... that time the imaging based on the electrical activity of the heart, such as electrocardiography (EKG). MRI ...

  14. MRI of the Chest

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    Full Text Available ... to detect and identify any metal objects. In general, metal objects used in orthopedic surgery pose no ... units provide very high quality images for many types of exams. Older open MRI units may not ...

  15. Constrained MRI Impedance Imaging

    National Research Council Canada - National Science Library

    Plewes, Donald

    2002-01-01

    An approach for imaging electric tissue properties in vivo is proposed. The technique relies upon the integration of MRI data with electrical potential measurements made over the surface of the patient...

  16. MRI of the Chest

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    Full Text Available ... you have any devices or metal in your body. Guidelines about eating and drinking before your exam ... soft tissues, bone and virtually all other internal body structures. MRI does not use ionizing radiation (x- ...

  17. MRI of the Chest

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    Full Text Available ... devices or metal in your body. Guidelines about eating and drinking before your exam vary between facilities. ... fitting and has no metal fasteners. Guidelines about eating and drinking before an MRI exam vary with ...

  18. MRI of the Chest

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    Full Text Available ... blood flow to the heart) and myocardial infarct (scar in the heart muscle due to prior obstruction ... contrast material except when absolutely necessary for medical treatment. See the MRI Safety page for more information ...

  19. MRI of the Chest

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    Full Text Available ... MRI examinations may require you to receive an injection of contrast material into the bloodstream. The radiologist , ... the potential risks. Pregnant women should not receive injections of gadolinium contrast material except when absolutely necessary ...

  20. MRI of the Chest

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    Full Text Available ... in the first three to four months of pregnancy unless the potential benefit from the MRI exam is assumed to outweigh the potential risks. Pregnant women should not receive injections of gadolinium ...

  1. MRI of the Chest

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    Full Text Available ... for more information. top of page How should I prepare? You may be asked to wear a ... total exam time. top of page What will I experience during and after the procedure? Most MRI ...

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    Full Text Available ... surgery pose no risk during MRI. However, a recently placed artificial joint may require the use of ... maintain your position without movement as much as possible. You will usually be alone in the exam ...

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    Full Text Available ... activated. Some centers provide earplugs, while others use headphones to reduce the intensity of the sounds made ... Children will be given appropriately sized earplugs or headphones during the exam. MRI scanners are air-conditioned ...

  4. MRI of the Chest

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    Full Text Available ... MRI) of the chest uses a powerful magnetic field, radio waves and a computer to produce detailed ... there’s a possibility you are pregnant. The magnetic field is not harmful, but it may cause some ...

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    Full Text Available ... by showing them a dummy scanner, play the noises that the child might hear during the MRI ... being imaged, send and receive radio waves, producing signals that are detected by the coils. The electric ...

  6. MRI of the Chest

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    Full Text Available ... any recent surgeries. Some conditions, such as severe kidney disease, may prevent you from being given gadolinium contrast ... an MRI. If you have a history of kidney disease or liver transplant, it will be necessary to ...

  7. MRI of the Chest

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    Full Text Available ... be examined on a computer monitor, transmitted electronically, printed or copied to a CD or uploaded to ... MRI exam, a physician, nurse or technologist will insert an intravenous (IV) catheter, also known as an ...

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    Full Text Available ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  10. MRI of the Chest

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    Full Text Available ... may cause some medical devices to malfunction. Most orthopedic implants pose no risk, but you should always ... metal objects. In general, metal objects used in orthopedic surgery pose no risk during MRI. However, a ...

  11. MRI of the Chest

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    Full Text Available ... the eyes are particularly important because they may move during the scan, possibly causing blindness. Dyes used in tattoos may contain iron and could heat up during an MRI scan, but this is rare. ...

  12. MRI of the Chest

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    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... radiation. MR images of the heart and vascular structures are often clearer and more detailed than with ...

  13. MRI of the Chest

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    Full Text Available ... scanner. top of page How does the procedure work? Unlike conventional x-ray examinations and computed tomography ( ... that magnetic resonance imaging harms the fetus, pregnant women usually are advised not to have an MRI ...

  14. MRI of the Chest

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    Full Text Available ... wall, pleura, heart and vessels, from almost any angle. MRI also provides movie-like sequential imaging of ... The images can then be studied from different angles by the interpreting radiologist. Frequently, the differentiation of ...

  15. MRI of the Chest

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    Full Text Available ... provides movie-like sequential imaging of the cardiovascular system that is important to assess the health and ... the magnet. Some MRI units, called short-bore systems , are designed so that the magnet does not ...

  16. MRI of the Chest

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    Full Text Available ... is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants pose no ... Chest? Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. ...

  17. MRI of the Chest

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    Full Text Available ... by showing them a dummy scanner, play the noises that the child might hear during the MRI exam, answer any questions and explain the procedure to relieve their anxiety. Some pediatric facilities also provide goggles or headsets ...

  18. MRI of the Chest

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    Full Text Available ... scanned and should not enter the MRI scanning area: cochlear (ear) implant some types of clips used ... but they may distort images of the facial area or brain, so you should let the radiologist ...

  19. MRI of the Chest

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    Full Text Available ... contrast for an MRI. If you have a history of kidney disease or liver transplant, it will ... data suggest that it is safe to continue breastfeeding after receiving intravenous contrast. For further information please ...

  20. MRI of the Chest

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    Full Text Available ... MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your ... there is any question of their presence, an x-ray may be taken to detect and identify ...

  1. MRI of the Chest

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    Full Text Available ... asked to wear a gown. If you have claustrophobia or anxiety, you may want to ask your ... information about pregnancy and MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may ...

  2. MRI of the Chest

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    Full Text Available ... vary between facilities. Unless you are told otherwise, take your regular medications as usual. Leave jewelry at ... you may follow your regular daily routine and take food and medications as usual. Some MRI examinations ...

  3. MRI of the Chest

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    Full Text Available ... Infants and young children usually require sedation or anesthesia to complete an MRI exam without moving. Whether ... A physician or nurse specializing in sedation or anesthesia for children should be available during the exam ...

  4. MRI of the Chest

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    Full Text Available ... vessels, from almost any angle. MRI also provides movie-like sequential imaging of the cardiovascular system that ... headsets so that the child can watch a movie while the scan is being performed. Thus, the ...

  5. MRI of the Chest

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    Full Text Available ... MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your ... imaging tests, treatments and procedures may vary by geographic region. Discuss the fees associated with your prescribed ...

  6. MRI of the Chest

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    Full Text Available ... in tattoos may contain iron and could heat up during an MRI scan, but this is rare. ... who will share the results with you. Follow-up examinations may be necessary. Your doctor will explain ...

  7. MRI of the Chest

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    Full Text Available ... copied to a CD or uploaded to a digital cloud server. MRI of the chest gives detailed ... physicians with expertise in several radiologic areas. Outside links: For the convenience of our users, RadiologyInfo .org ...

  8. MRI of the Chest

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    Full Text Available ... will hear and feel loud tapping or thumping sounds when the coils that generate the radiofrequency pulses ... use headphones to reduce the intensity of the sounds made by the MRI machine. You may be ...

  9. MRI of the Chest

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    Full Text Available ... their nature and the strength of the MRI magnet. Many implanted devices will have a pamphlet explaining ... large cylinder-shaped tube surrounded by a circular magnet. You will lie on a moveable examination table ...

  10. MRI of the Chest

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. Other coils, located in the machine and in some cases, placed around the part ...

  11. Sinus MRI scan

    Science.gov (United States)

    ... tissues surrounding the eye (orbital cellulitis) Nasal polyps Sinusitis -- acute Sinusitis -- chronic Talk to your provider if you have ... therefore is not typically used for suspected acute sinusitis. Alternative Names MRI of the sinuses; Magnetic resonance ...

  12. MRI of the Chest

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    Full Text Available ... traditional MRI unit is a large cylinder-shaped tube surrounded by a circular magnet. You will lie ... your skin at the site of the IV tube insertion. Some patients may sense a temporary metallic ...

  13. MRI of the Chest

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    Full Text Available ... imaging (MRI) exam. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. ...

  14. MRI of the Chest

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. ... signals that are detected by the coils. The electric current does not come in contact with the ...

  15. MRI of the Chest

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    Full Text Available ... with claustrophobia. Newer open MRI units provide very high quality images for many types of exams. Older ... believed to be caused by the injection of high doses of gadolinium-based contrast material in patients ...

  16. Combined PET/MRI

    DEFF Research Database (Denmark)

    Bailey, D. L.; Pichler, B. J.; Gückel, B.

    2015-01-01

    This paper summarises key themes and discussions from the 4th international workshop dedicated to the advancement of the technical, scientific and clinical applications of combined positron emission tomography (PET)/magnetic resonance imaging (MRI) systems that was held in Tübingen, Germany, from...... February 23 to 27, 2015. Specifically, we summarise the three days of invited presentations from active researchers in this and associated fields augmented by round table discussions and dialogue boards with specific topics. These include the use of PET/MRI in cardiovascular disease, paediatrics, oncology......, neurology and multi-parametric imaging, the latter of which was suggested as a key promoting factor for the wider adoption of integrated PET/MRI. Discussions throughout the workshop and a poll taken on the final day demonstrated that attendees felt more strongly that PET/MRI has further advanced in both...

  17. MRI of the Chest

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    Full Text Available ... body. Guidelines about eating and drinking before your exam vary between facilities. Unless you are told otherwise, ... doctor for a mild sedative prior to the exam. What is MRI of the Chest? What are ...

  18. MRI of the Chest

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    Full Text Available ... that the child might hear during the MRI exam, answer any questions and explain the procedure to relieve their anxiety. Some pediatric facilities also provide goggles or headsets ...

  19. MRI of the Chest

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    Full Text Available ... by showing them a dummy scanner, play the noises that the child might hear during the MRI ... a noninvasive imaging technique that does not involve exposure to ionizing radiation. MR images of the heart ...

  20. MRI of the Chest

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    Full Text Available ... images removable dental work pens, pocket knives and eyeglasses body piercings In most cases, an MRI exam ... Foreign bodies near and especially lodged in the eyes are particularly important because they may move during ...

  1. MRI of the Chest

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    Full Text Available ... copied to a CD or uploaded to a digital cloud server. MRI of the chest gives detailed ... type your comment or suggestion into the following text box: Comment: E-mail: Area code: Phone no: ...

  2. MRI of the Chest

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    Full Text Available ... high quality images for many types of exams. Older open MRI units may not provide this same ... You may resume your usual activities and normal diet immediately after the exam. On very rare occasions, ...

  3. MRI of the Chest

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    Full Text Available ... ports artificial limbs or metallic joint prostheses implanted nerve stimulators metal pins, screws, plates, stents or surgical ... the magnet. Some MRI units, called short-bore systems , are designed so that the magnet does not ...

  4. MRI of the Chest

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    Full Text Available ... patient story here Images × Image Gallery Radiologist preparing patient for magnetic resonance imaging (MRI) exam. View full size with caption Pediatric Content Some imaging tests and treatments have special ...

  5. MRI of the Chest

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    Full Text Available ... prior to your scheduled examination. Infants and young children usually require sedation or anesthesia to complete an MRI exam without moving. Whether a child requires sedation depends on the child's age, intellectual ...

  6. MRI of the Chest

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    Full Text Available ... over time. top of page What are the benefits vs. risks? Benefits MRI is a noninvasive imaging technique that does ... data suggest that it is safe to continue breastfeeding after receiving intravenous contrast. For further information please ...

  7. MRI of the Chest

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    Full Text Available ... the same effect. A very irregular heartbeat may affect the quality of images obtained using techniques that ... time an MRI takes to complete, many young children and infants require sedation to hold still for ...

  8. MRI of the Chest

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    Full Text Available ... used in tattoos may contain iron and could heat up during an MRI scan, but this is ... special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) ...

  9. MRI of the Chest

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    Full Text Available ... MRI exams is less likely to produce an allergic reaction than the iodine-based contrast materials used for ... There is a very slight risk of an allergic reaction if contrast material is injected. Such reactions are ...

  10. MRI of the Chest

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    Full Text Available ... being safe for MRI examinations. Examples include but are not limited to: artificial heart valves implanted drug infusion ports artificial limbs or metallic joint prostheses implanted nerve stimulators metal pins, screws, plates, ...

  11. MRI of the Chest

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    Full Text Available ... your regular medications as usual. Leave jewelry at home and wear loose, comfortable clothing. You may be ... Jewelry and other accessories should be left at home, if possible, or removed prior to the MRI ...

  12. MRI of the Chest

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    Full Text Available ... internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to ... x-ray contrast material, drugs, food, or the environment, or if you have asthma. The contrast material ...

  13. MRI of the Chest

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    Full Text Available ... Older open MRI units may not provide this same image quality. Certain types of exams cannot be ... the metallic objects. Patient movement can have the same effect. A very irregular heartbeat may affect the ...

  14. MRI of the Chest

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    Full Text Available ... may follow your regular daily routine and take food and medications as usual. Some MRI examinations may ... to iodine or x-ray contrast material, drugs, food, or the environment, or if you have asthma. ...

  15. MRI of the Chest

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    Full Text Available ... may have. top of page What does the equipment look like? The traditional MRI unit is a ... traction devices and many types of life support equipment may distort the MR images and as a ...

  16. MRI of the Chest

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    Full Text Available ... evaluation with additional views or a special imaging technique. A follow-up examination may also be necessary ... vs. risks? Benefits MRI is a noninvasive imaging technique that does not involve exposure to ionizing radiation. ...

  17. MRI of the Chest

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    Full Text Available ... systemic fibrosis is currently a recognized, but rare, complication of MRI believed to be caused by the ... injection minimizes the risk of this very rare complication. There is a very slight risk of an ...

  18. MRI of the Chest

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    Full Text Available ... devices they may have. top of page What does the equipment look like? The traditional MRI unit ... room from the scanner. top of page How does the procedure work? Unlike conventional x-ray examinations ...

  19. MRI of the Chest

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    Full Text Available ... implanted drug infusion ports artificial limbs or metallic joint prostheses implanted nerve stimulators metal pins, screws, plates, ... risk during MRI. However, a recently placed artificial joint may require the use of another imaging procedure. ...

  20. MRI of the Chest

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    Full Text Available ... metal in your body. Guidelines about eating and drinking before your exam vary between facilities. Unless you ... has no metal fasteners. Guidelines about eating and drinking before an MRI exam vary with the specific ...