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MR elastography

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https://www.readbyqxmd.com/read/28344811/the-role-of-imaging-in-the-diagnosis-of-primary-prostate-cancer
#1
Hugh Harvey, Nandita M deSouza
Ultrasound and magnetic resonance imaging (MRI) are key imaging modalities in prostate cancer diagnosis. MRI offers a range of intrinsic contrast mechanisms (T2, diffusion-weighted imaging (DWI), MR spectroscopy (MRS)) and extrinsic contrast-generating options based on tumour vascular state following injection of weakly paramagnetic agents such as gadolinium. Together these parameters are referred to as multiparametric (mp)MRI and are used for detecting and guiding biopsy and staging prostate cancer. Although sensitivity of mpMRI is <75% for disease detection, specificity is >90% and a standardised reporting system together with MR-guided targeted biopsy is the optimal diagnostic pathway...
December 2016: Journal of Clinical Urology
https://www.readbyqxmd.com/read/28333623/a-comparison-of-fem-based-inversion-algorithms-local-frequency-estimation-and-direct-inversion-approach-used-in-mr-elastography
#2
Mohammad Honarvar, Ramin Sahebjavaher, Robert Rohling, Septimiu Salcudean
In quantitative elastography, maps of the mechanical properties of soft tissue, or elastograms, are calculated from the measured displacement data by solving an inverse problem. The model assumptions have a significant effect on elastograms. Motivated by the high sensitivity of imaging results to the model assumptions for in-vivo Magnetic Resonance Elastography (MRE) of the prostate, we compared elastograms obtained with four different methods. Two FEM-based methods developed by our group were compared with two other commonly used methods, Local Frequency Estimator (LFE) and curl-based Direct Inversion (c-DI)...
March 22, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28321914/a-compact-0-5%C3%A2-t-mr-elastography-device-and-its-application-for-studying-viscoelasticity-changes-in-biological-tissues-during-progressive-formalin-fixation
#3
Jürgen Braun, Heiko Tzschätzsch, Clara Körting, Angela Ariza de Schellenberger, Marika Jenderka, Toni Drießle, Michael Ledwig, Ingolf Sack
PURPOSE: To develop a method of compact tabletop magnetic resonance elastography (MRE) for rheological tests of tissue samples and to measure changes in viscoelastic powerlaw constants of liver and brain tissue during progressive fixation. METHODS: A 10-mm bore, 0.5-T permanent-magnet-based MRI system was equipped with a gradient-amplifier-controlled piezo-actuator and motion-sensitive spin echo sequence for inducing and measuring harmonic shear vibrations in cylindrical samples...
March 20, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28289936/comparison-of-spin-echo-echoplanar-imaging-and-gradient-recalled-echo-based-mr-elastography-at-3-tesla-with-and-without-gadoxetic-acid-administration
#4
Yong Seek Kim, Ji Soo Song, Stephan Kannengiesser, Seung Young Seo
OBJECTIVE: To compare spin-echo echoplanar imaging (SE-EPI) and gradient recalled echo (GRE) MR elastography (MRE) at 3 T with and without gadoxetic acid administration. METHODS: We included 84 patients who underwent MRE before and after gadoxetic acid administration, each time using SE-EPI and GRE sequences. Diagnostic performance for predicting clinical liver cirrhosis and high-risk oesophageal varices was assessed using the area under the receiver-operating characteristic curve (AUC)...
March 13, 2017: European Radiology
https://www.readbyqxmd.com/read/28277807/magnetic-resonance-imaging-and-transient-elastography-in-the-management-of-nonalcoholic-fatty-liver-disease-nafld
#5
Ma Ai Thanda Han, Rola Saouaf, Walid Ayoub, Tsuyoshi Todo, Edward Mena, Mazen Noureddin
Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and cirrhosis worldwide and the second most common cause of liver transplantation in major medical centers. Because liver steatosis and fibrosis severity are related to disease morbidity and mortality, the extent of disease, and disease progression, they need to be assessed and monitored. In addition, innovation with new drug developments requires disease staging and monitoring in both phase 2 and 3 clinical trials. Currently, disease assessment in both clinical practice and research is mostly performed by liver biopsy, an invasive, procedure with risks...
April 2017: Expert Review of Clinical Pharmacology
https://www.readbyqxmd.com/read/28252868/early-diagnosis-and-severity-assessment-of-acute-pancreatitis-ap-using-mr-elastography-mre-with-spin-echo-echo-planar-imaging
#6
Yu Shi, Ying Liu, Yan-Qing Liu, Feng Gao, Jia-Hui Li, Qiu-Ju Li, Qi-Yong Guo
PURPOSE: To evaluate the accuracy of magnetic resonance elastography (MRE) in comparison to contrast-enhanced computed tomography (CE-CT) for early diagnosis and prediction of severity in acute pancreatitis (AP). MATERIALS AND METHODS: This cross-sectional prospective study included 76 patients with suspected AP who underwent both CE-CT and 3.0T MRE within 24 hours of hospital admission. Pancreatic stiffness, CT severity index (CTSI), Acute Physiology and Chronic Health Evaluation (APACHE)-II, and Bedside Index for Severity in AP (BISAP) scores were comparatively evaluated using data from the first 24 hours of admission, and diagnosis and severity of AP were confirmed according to the revised Atlanta Classification (2012)...
March 2, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28236336/cardiac-mr-elastography-for-quantitative-assessment-of-elevated-myocardial-stiffness-in-cardiac-amyloidosis
#7
Arvin Arani, Shivaram P Arunachalam, Ian C Y Chang, Francis Baffour, Phillip J Rossman, Kevin J Glaser, Joshua D Trzasko, Kiaran P McGee, Armando Manduca, Martha Grogan, Angela Dispenzieri, Richard L Ehman, Philip A Araoz
PURPOSE: To evaluate if cardiac magnetic resonance elastography (MRE) can measure increased stiffness in patients with cardiac amyloidosis. Myocardial tissue stiffness plays an important role in cardiac function. A noninvasive quantitative imaging technique capable of measuring myocardial stiffness could aid in disease diagnosis, therapy monitoring, and disease prognostic strategies. We recently developed a high-frequency cardiac MRE technique capable of making noninvasive stiffness measurements...
February 25, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28218814/mr-elastography-measurement-of-the-effect-of-passive-warmup-prior-to-eccentric-exercise-on-thigh-muscle-mechanical-properties
#8
Paul Kennedy, Lewis J Macgregor, Eric Barnhill, Curtis L Johnson, Michael Perrins, Angus Hunter, Colin Brown, Edwin J R van Beek, Neil Roberts
PURPOSE: To investigate the effect of warmup by application of the thermal agent Deep Heat (DH) on muscle mechanical properties using magnetic resonance elastography (MRE) at 3T before and after exercise-induced muscle damage (EIMD). MATERIALS AND METHODS: Twenty male participants performed an individualized protocol designed to induce EIMD in the quadriceps. DH was applied to the thigh in 50% of the participants before exercise. MRE, T2 -weighted MRI, maximal voluntary contraction (MVC), creatine kinase (CK) concentration, and muscle soreness were measured before and after the protocol to assess EIMD effects...
February 20, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28194925/slip-interface-imaging-based-on-mr-elastography-preoperatively-predicts-meningioma-brain-adhesion
#9
Ziying Yin, Joshua D Hughes, Kevin J Glaser, Armando Manduca, Jamie Van Gompel, Michael J Link, Anthony Romano, Richard L Ehman, John Huston
PURPOSE: To investigate the ability of slip interface imaging (SII), a recently developed magnetic resonance elastography (MRE)-based technique, to predict the degree of meningioma-brain adhesion, using findings at surgery as the reference standard. MATERIALS AND METHODS: With Institutional Review Board approval and written informed consent, 25 patients with meningiomas >2.5 cm in maximal diameter underwent preoperative SII assessment. Intracranial shear motions were introduced using a soft, pillow-like head driver and the resulting displacement field was acquired with an MRE pulse sequence on 3T MR scanners...
February 14, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28164361/in-vivo-quantification-of-aortic-stiffness-using-mr-elastography-in-hypertensive-porcine-model
#10
Huiming Dong, Ria Mazumder, Venkata Sita Priyanka Illapani, Xiaokui Mo, Richard D White, Arunark Kolipaka
PURPOSE: Aortic stiffness plays an important role in evaluating and predicting the progression of systemic arterial hypertension (SAH). The aim of this study is to determine the stiffness of aortic wall using MR elastography (MRE) in a hypertensive porcine model and compare it against invasive aortic pressure measurements. METHODS: Renal wrapping surgery was performed on eight pigs to induce SAH. Aortic MRE was performed at baseline and 2 months postsurgery using a retrospectively pulse-gated gradient-echo MRE sequence on a 1...
February 5, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28154910/value-of-tumor-stiffness-measured-with-mr-elastography-for-assessment-of-response-of-hepatocellular-carcinoma-to-locoregional-therapy
#11
Sonja Gordic, Jad Bou Ayache, Paul Kennedy, Cecilia Besa, Mathilde Wagner, Octavia Bane, Richard L Ehman, Edward Kim, Bachir Taouli
PURPOSE: The aim of the study was to correlate tumor stiffness (TS) measured with MR elastography (MRE) with degree of tumor enhancement and necrosis on contrast-enhanced T1-weighted imaging (CE-T1WI) in hepatocellular carcinomas (HCC) treated with Yttrium-90 radioembolization (RE) or transarterial chemoembolization plus radiofrequency ablation (TACE/RFA). MATERIAL AND METHODS: This retrospective study was IRB-approved and the requirement for informed consent was waived...
February 2, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28128707/distinguishing-between-hepatic-inflammation-and-fibrosis-with-mr-elastography
#12
Meng Yin, Kevin J Glaser, Armando Manduca, Taofic Mounajjed, Harmeet Malhi, Douglas A Simonetto, Ruisi Wang, Liu Yang, Shennen A Mao, Jaime M Glorioso, Faysal M Elgilani, Christopher J Ward, Peter C Harris, Scott L Nyberg, Vijay H Shah, Richard L Ehman
Purpose To investigate the utility of magnetic resonance (MR) elastography-derived mechanical properties in the discrimination of hepatic inflammation and fibrosis in the early stages of chronic liver diseases. Materials and Methods All studies were approved by the institutional animal care and use committee. A total of 187 animals were studied, including 182 mice and five pigs. These animals represented five different liver diseases with a varying combination and extent of hepatic inflammation, fibrosis, congestion, and portal hypertension...
January 27, 2017: Radiology
https://www.readbyqxmd.com/read/28117930/quantitative-assessment-of-lung-stiffness-in-patients-with-interstitial-lung-disease-using-mr-elastography
#13
John P Marinelli, David L Levin, Robert Vassallo, Rickey E Carter, Rolf D Hubmayr, Richard L Ehman, Kiaran P McGee
PURPOSE: To investigate the use of magnetic resonance elastography (MRE) in the quantitative assessment of pulmonary fibrosis by comparing quantitative shear stiffness measurements of lung parenchyma in patients diagnosed with fibrotic interstitial lung disease (ILD) and healthy controls. MATERIALS AND METHODS: A 1.5T spin-echo, echo planar imaging MRE (SE-EPI MRE) pulse sequence was utilized to assess absolute lung shear stiffness in 15 patients with diagnosed ILD and in 11 healthy controls...
January 24, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28113575/gradient-based-optimization-for-poroelastic-and-viscoelastic-mr-elastography
#14
Likun Tan, Matthew McGarry, Elijah Van Houten, Ming Ji, Ligin Solamen, John Weaver, Keith Paulsen
We describe an efficient gradient computation for solving inverse problems arising in magnetic resonance elastography (MRE). The algorithm can be considered as a generalized 'adjoint method' based on a Lagrangian formulation. One requirement for the classic adjoint method is assurance of the self-adjoint property of the stiffness matrix in the elasticity problem. In this paper, we show this property is no longer a necessary condition in our algorithm, but the computational performance can be as efficient as the classic method, which involves only two forward solutions and is independent of the number of parameters to be estimated...
August 31, 2016: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28092638/mr-elastography-to-measure-the-effects-of-cancer-and-pathology-fixation-on-prostate-biomechanics-and-comparison-with-t-1-t-2-and-adc
#15
Deirdre M McGrath, Jenny Lee, Warren D Foltz, Navid Samavati, Theo van der Kwast, Michael A S Jewett, Peter Chung, Cynthia Ménard, Kristy K Brock
MRI is under evaluation for image-guided intervention for prostate cancer. The sensitivity and specificity of MRI parameters is determined via correlation with the gold-standard of histopathology. Whole-mount histopathology of prostatectomy specimens can be digitally registered to in vivo imaging for correlation. When biomechanical-based deformable registration is employed to account for deformation during histopathology processing, the ex vivo biomechanical properties are required. However, these properties are altered by pathology fixation, and vary with disease...
February 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28076414/a-mri-compatible-combined-mechanical-loading-and-mr-elastography-setup-to-study-deformation-induced-skeletal-muscle-damage-in-rats
#16
Jules L Nelissen, Larry de Graaf, Willeke A Traa, Tom J L Schreurs, Kevin M Moerman, Aart J Nederveen, Ralph Sinkus, Cees W J Oomens, Klaas Nicolay, Gustav J Strijkers
Deformation of skeletal muscle in the proximity of bony structures may lead to deep tissue injury category of pressure ulcers. Changes in mechanical properties have been proposed as a risk factor in the development of deep tissue injury and may be useful as a diagnostic tool for early detection. MRE allows for the estimation of mechanical properties of soft tissue through analysis of shear wave data. The shear waves originate from vibrations induced by an external actuator placed on the tissue surface. In this study a combined Magnetic Resonance (MR) compatible indentation and MR Elastography (MRE) setup is presented to study mechanical properties associated with deep tissue injury in rats...
2017: PloS One
https://www.readbyqxmd.com/read/28057657/measuring-shear-wave-speed-with-point-shear-wave-elastography-and-mr-elastography-a-phantom-study
#17
Riwa Kishimoto, Mikio Suga, Atsuhisa Koyama, Tokuhiko Omatsu, Yasuhiko Tachibana, Daniel K Ebner, Takayuki Obata
OBJECTIVES: To compare shear-wave speed (SWS) measured by ultrasound-based point shear-wave elastography (pSWE) and MR elastography (MRE) on phantoms with a known shear modulus, and to assess method validity and variability. METHODS: 5 homogeneous phantoms of different stiffnesses were made. Shear modulus was measured by a rheometer, and this value was used as the standard. 10 SWS measurements were obtained at 4 different depths with 1.0-4.5 MHz convex (4C1) and 4...
January 5, 2017: BMJ Open
https://www.readbyqxmd.com/read/28045604/technical-failure-of-mr-elastography-examinations-of-the-liver-experience-from-a-large-single-center-study
#18
Mathilde Wagner, Idoia Corcuera-Solano, Grace Lo, Steven Esses, Joseph Liao, Cecilia Besa, Nelson Chen, Ginu Abraham, Maggie Fung, James S Babb, Richard L Ehman, Bachir Taouli
Purpose To assess the determinants of technical failure of magnetic resonance (MR) elastography of the liver in a large single-center study. Materials and Methods This retrospective study was approved by the institutional review board. Seven hundred eighty-one MR elastography examinations performed in 691 consecutive patients (mean age, 58 years; male patients, 434 [62.8%]) in a single center between June 2013 and August 2014 were retrospectively evaluated. MR elastography was performed at 3.0 T (n = 443) or 1...
January 3, 2017: Radiology
https://www.readbyqxmd.com/read/28039886/combined-magnetic-resonance-elastography-and-collagen-molecular-magnetic-resonance-imaging-accurately-stage-liver-fibrosis-in-a-rat-model
#19
Bo Zhu, Lan Wei, Nicholas Rotile, Helen Day, Tyson Rietz, Christian T Farrar, Gregory Y Lauwers, Kenneth K Tanabe, Bruce Rosen, Bryan C Fuchs, Peter Caravan
Hepatic fibrosis is associated with an overproduction of matrix proteins and a pathological increase of liver stiffness. Noninvasive magnetic resonance (MR) quantification of matrix can be assessed with a collagen-binding molecular MR probe and stiffness by MR elastography, complementary techniques. This study used both imaging techniques to more accurately stage hepatic fibrosis in a rat model. Thirty rats with varying levels of diethylnitrosamine-induced liver fibrosis were imaged before and 45 minutes after injection of collagen-specific probe EP-3533...
March 2017: Hepatology: Official Journal of the American Association for the Study of Liver Diseases
https://www.readbyqxmd.com/read/27986169/hepatic-steatosis-etiology-patterns-and-quantification
#20
Ilkay S Idilman, Ilknur Ozdeniz, Musturay Karcaaltincaba
Hepatic steatosis can occur because of nonalcoholic fatty liver disease (NAFLD), alcoholism, chemotherapy, and metabolic, toxic, and infectious causes. Pediatric hepatic steatosis is also becoming more frequent and can have distinctive features. The most common pattern is diffuse form; however, it can present in heterogenous, focal, multinodular, perilesional, perivascular, subcapsular, and lobar forms. Focal steatosis and fat sparing can occur because of the presence of veins of Sappey, pancreaticoduodenal vein, and aberrant right and left gastric veins, which drain into the liver as third inflow...
December 2016: Seminars in Ultrasound, CT, and MR
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