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MR elastography

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https://www.readbyqxmd.com/read/28915103/mr-spectroscopy-derived-proton-density-fat-fraction-is-superior-to-controlled-attenuation-parameter-for-detecting-and-grading-hepatic-steatosis
#1
Jurgen Henk Runge, Loek Pieter Smits, Joanne Verheij, Annekatrien Depla, Sjoerd Douwe Kuiken, Bert Cornelis Baak, Aart Johannes Nederveen, Ulrich Beuers, Jaap Stoker
Purpose To prospectively compare the diagnostic accuracy of controlled attenuation parameter (CAP) obtained with transient elastography and proton density fat fraction (PDFF) obtained with proton magnetic resonance (MR) spectroscopy with results of liver biopsy in a cohort of adult patients suspected of having nonalcoholic fatty liver disease (NAFLD). Materials and Methods The institutional review board approved this study. Informed consent was obtained from all patients. The authors evaluated 55 patients suspected of having NAFLD (40 men, 15 women)...
September 15, 2017: Radiology
https://www.readbyqxmd.com/read/28914407/association-of-fetuin-b-with-markers-of-liver-fibrosis-in-nonalcoholic-fatty-liver-disease
#2
Thomas Ebert, Nicolas Linder, Alexander Schaudinn, Harald Busse, Joachim Berger, Ralf Lichtinghagen, Volker Keim, Johannes Wiegand, Thomas Karlas
OBJECTIVE: The liver-derived plasma protein fetuin B is associated with nonalcoholic fatty liver disease (NAFLD) and impaired glucose homeostasis in mice. However, its association with non-invasive ultrasound- and magnetic resonance (MR)-based markers of liver fibrosis and steatosis, the enhanced liver fibrosis (ELF) score, liver biopsy, as well as rs738409 in PNPLA3, has not been elucidated in NAFLD, so far. DESIGN AND METHODS: The association of circulating fetuin B and transient elastography (TE), controlled attenuation parameter (CAP), (1)H-MR-spectroscopy, the ELF score, liver biopsy, as well as risk alleles in rs738409 in PNPLA3, was studied in 101 NAFLD patients as compared to 15 healthy controls...
September 15, 2017: Endocrine
https://www.readbyqxmd.com/read/28866387/static-and-dynamic-liver-stiffness-an-ex-vivo-porcine-liver-study-using-mr-elastography
#3
Chun Yang, Meng Yin, Kevin J Glaser, Xiangyang Zhu, Kai Xu, Richard L Ehman, Jun Chen
Magnetic resonance elastography (MRE) is an MRI-based noninvasive technique for quantitatively assessing tissue stiffness. The hypothesis of this study is that stiffness increases with portal pressure. We further hypothesized that the rate of stiffness change with pressure would be larger in liver tissue treated to simulate the stiffening effects of fibrosis. In agreement with our hypothesis, the formalin-treated livers were stiffer than the untreated livers, and in both groups the liver stiffness increased with portal venous pressure...
September 1, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28856718/tomoelastography-of-the-native-kidney-regional-variation-and-physiological-effects-on-in-vivo-renal-stiffness
#4
Stephan Rodrigo Marticorena Garcia, Markus Grossmann, Sophia Theresa Lang, Heiko Tzschätzsch, Florian Dittmann, Bernd Hamm, Jürgen Braun, Jing Guo, Ingolf Sack
PURPOSE: To measure normal renal stiffness in adults, taking into account regional variation, hydration, and urinary status. METHODS: Thirty-six healthy volunteers were examined by tomoelastography based on MR elastography at four frequencies, from 40 to 70 Hz and multifrequency shear wave speed recovery. Regional wave speeds were derived for the medulla, cortex (inner cortex and outer cortex), and renal pelvis, and examined for age-related effects. Subgroups were repeatedly examined for reproducibility, amount of prior water drinking, and urinary status...
August 30, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28837671/development-of-acute-hydrocephalus-does-not-change-brain-tissue-mechanical-properties-in-adult-rats-but-in-juvenile-rats
#5
Alice C Pong, Lauriane Jugé, Lynne E Bilston, Shaokoon Cheng
INTRODUCTION: Regional changes in brain stiffness were previously demonstrated in an experimental obstructive hydrocephalus juvenile rat model. The open cranial sutures in the juvenile rats have influenced brain compression and mechanical properties during hydrocephalus development and the extent by which closed cranial sutures in adult hydrocephalic rat models affect brain stiffness in-vivo remains unclear. The aims of this study were to determine changes in brain tissue mechanical properties and brain structure size during hydrocephalus development in adult rat with fixed cranial volume and how these changes were related to brain tissue deformation...
2017: PloS One
https://www.readbyqxmd.com/read/28801939/assessment-of-advanced-hepatic-mr-elastography-methods-for-susceptibility-artifact-suppression-in-clinical-patients
#6
Jin Wang, Kevin J Glaser, Tianhui Zhang, Qungang Shan, Bingjun He, Jun Chen, Meng Yin, Bogdan Dzyubak, Jennifer L Kugel, Scott A Kruse, Roger C Grimm, Sudhakar K Venkatesh, Richard L Ehman
PURPOSE: To assess the success rate, image quality, and the ability to stage liver fibrosis of a standard 2D gradient-recalled echo (GRE) and four different spin-echo (SE) magnetic resonance elastography (MRE) sequences in patients with different liver iron concentrations. MATERIALS AND METHODS: A total of 332 patients who underwent 3T MRE examinations that included liver fat and iron quantification were enrolled, including 136 patients with all five MRE techniques...
August 11, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28777745/simultaneous-3d-mr-elastography-of-the-in-vivo-mouse-brain
#7
Steven P Kearney, Shreyan Majumdar, Thomas J Royston, Dieter Klatt
The feasibility of sample interval modulation (SLIM) magnetic resonance elastography (MRE) for the in vivo mouse brain is assessed, and an alternative SLIM-MRE encoding method is introduced. In SLIM-MRE, the phase accumulation for each motion direction is encoded simultaneously by varying either the start time of the motion encoding gradient (MEG), SLIM-phase constant (SLIM-PC), or the initial phase of the MEG, SLIM-phase varying (SLIM-PV). SLIM-PC provides gradient moment nulling, but the mutual gradient shift necessitates increased echo time (TE)...
September 15, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28752925/management-of-portal-hypertension-before-and-after-liver-transplantation
#8
L W Unger, G Berlakovich, M Trauner, T Reiberger
Orthotopic liver transplantation (OLT) represents a curative treatment option for end-stage liver disease (ESLD). While epidemiology of ESLD has recently changed due the rising prevalence of non-alcoholic fatty liver disease (NAFLD) and decreased burden of hepatitis C virus (HCV) infections due to highly-effective antiviral regimens, the management of portal hypertension (PHT) remains a clinical challenge in the pre- and post-OLT setting. The measurement of hepatic venous pressure gradient (HVPG) represents the most reliable, but invasive tool for assessment of the severity of PHT...
July 28, 2017: Liver Transplantation
https://www.readbyqxmd.com/read/28723710/controlled-attenuation-parameter-and-mr-spectroscopy-measured-liver-steatosis-are-discordant-in-hiv-infected-adults-with-high-body-mass
#9
Jennifer C Price, Jennifer L Dodge, Yifei Ma, Rebecca Scherzer, Natalie Korn, Kyle Tillinghast, Marion G Peters, Susan Noworolski, Phyllis C Tien
OBJECTIVE: Hepatic steatosis (HS) is common in HIV-infected individuals. Magnetic resonance spectroscopy (MRS) is the preferred non-invasive method for HS measurement but is expensive. Controlled attenuation parameter (CAP) also assesses HS and is conveniently performed concomitantly with transient elastography. We aimed to assess the accuracy of CAP in the setting of HIV infection. DESIGN: Cross-sectional study. METHODS: CAP and MRS were performed in 82 subjects (39 HIV-monoinfected;7 HCV-monoinfected;21 HIV/HCV-coinfected; 15 with neither infection)...
July 18, 2017: AIDS
https://www.readbyqxmd.com/read/28669751/finite-element-analysis-to-investigate-variability-of-mr-elastography-in-the-human-thigh
#10
L Hollis, E Barnhill, M Perrins, P Kennedy, N Conlisk, C Brown, P R Hoskins, P Pankaj, N Roberts
PURPOSE: To develop finite element analysis (FEA) of magnetic resonance elastography (MRE) in the human thigh and investigate inter-individual variability of measurement of muscle mechanical properties. METHODS: Segmentation was performed on MRI datasets of the human thigh from 5 individuals and FEA models consisting of 12 muscles and surrounding tissue created. The same material properties were applied to each tissue type and a previously developed transient FEA method of simulating MRE using Abaqus was performed at 4 frequencies...
June 29, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28660330/quantitative-mri-of-kidneys-in-renal-disease
#11
Timothy L Kline, Marie E Edwards, Ishan Garg, Maria V Irazabal, Panagiotis Korfiatis, Peter C Harris, Bernard F King, Vicente E Torres, Sudhakar K Venkatesh, Bradley J Erickson
PURPOSE: To evaluate the reproducibility and utility of quantitative magnetic resonance imaging (MRI) sequences for the assessment of kidneys in young adults with normal renal function (eGFR ranged from 90 to 130 mL/min/1.73 m(2)) and patients with early renal disease (autosomal dominant polycystic kidney disease). MATERIALS AND METHODS: This prospective case-control study was performed on ten normal young adults (18-30 years old) and ten age- and sex-matched patients with early renal parenchymal disease (autosomal dominant polycystic kidney disease)...
June 28, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28654854/viscoelastic-power-law-parameters-of-in-vivo-human-brain-estimated-by-mr-elastography
#12
J Testu, M D J McGarry, F Dittmann, J B Weaver, K D Paulsen, I Sack, E E W Van Houten
The noninvasive imaging technique of magnetic resonance elastography (MRE) was used to estimate the power law behavior of the viscoelastic properties of the human brain in vivo. The mechanical properties for four volunteers are investigated using shear waves induced over a frequency range of 10-50Hz to produce a displacement field measured by magnetic resonance motion-encoding gradients. The average storage modulus (μR) reconstructed with non-linear inversion (NLI) increased from approximately 0.95 to 2.58kPa over the 10-50Hz span; the average loss modulus (μI) also increased from 0...
October 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28612163/repeatability-and-reproducibility-of-2d-and-3d-hepatic-mr-elastography-with-rigid-and-flexible-drivers-at-end-expiration-and-end-inspiration-in-healthy-volunteers
#13
Kang Wang, Paul Manning, Nikolaus Szeverenyi, Tanya Wolfson, Gavin Hamilton, Michael S Middleton, Florin Vaida, Meng Yin, Kevin Glaser, Richard L Ehman, Claude B Sirlin
PURPOSE: To evaluate the repeatability and reproducibility of 2D and 3D hepatic MRE with rigid and flexible drivers at end-expiration and end-inspiration in healthy volunteers. MATERIALS AND METHODS: Nine healthy volunteers underwent two same-day MRE exams separated by a 5- to 10-min break. In each exam, 2D and 3D MRE scans were performed, each under four conditions (2 driver types [rigid, flexible] × 2 breath-hold phases [end-expiration, end-inspiration]). Repeatability (measurements under identical conditions) and reproducibility (measurements under different conditions) were analyzed by calculating bias, limit of agreement, repeatability coefficient (RC), reproducibility coefficient (RDC), intraclass correlation coefficient (ICC), and concordance correlation coefficient (CCC), as appropriate...
June 13, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28604279/diffusion-and-intravoxel-incoherent-motion-mr-imaging-based-virtual-elastography-a-hypothesis-generating-study-in-the-liver
#14
Denis Le Bihan, Shintaro Ichikawa, Utaroh Motosugi
Purpose To investigate the potential of diffusion magnetic resonance (MR) imaging to provide quantitative estimates of tissue stiffness without using mechanical vibrations in patients with chronic liver diseases and to generate a new elasticity-driven intravoxel incoherent motion (IVIM) contrast. Materials and Methods This retrospective study, conducted from January to April 2016, was approved by an institutional review board that waived the requirement for informed consent. Fifteen subjects were included (13 men and two women; mean age ± standard deviation, 73 years ± 8)...
June 12, 2017: Radiology
https://www.readbyqxmd.com/read/28585229/tomoelastography-of-the-prostate-using-multifrequency-mr-elastography-and-externally-placed-pressurized-air-drivers
#15
Florian Dittmann, Rolf Reiter, Jing Guo, Matthias Haas, Patrick Asbach, Thomas Fischer, Jürgen Braun, Ingolf Sack
PURPOSE: To demonstrate the feasibility of in vivo multifrequency magnetic resonance elastography (MRE) of the prostate using externally placed drivers. METHODS: Three pressurized-air drivers were used to excite shear waves within the prostate at vibration frequencies of 60, 70, and 80 Hz. Full 3D wave fields were acquired by multislice spin-echo echo-planar imaging in conjunction with tomoelastography wave speed recovery for generating full field-of-view stiffness maps...
June 6, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28583636/metabolic-profile-of-liver-damage-in-non-cirrhotic-virus-c-and-autoimmune-hepatitis-a-proton-decoupled-31-p-mrs-study
#16
Antti Hakkarainen, Lauri Puustinen, Reetta Kivisaari, Sonja Boyd, Urpo Nieminen, Perttu Arkkila, Nina Lundbom
PURPOSE: To study liver (31)P MRS, histology, transient elastography, and liver function tests in patients with virus C hepatitis (HCV) or autoimmune hepatitis (AIH) to test the hypothesis that (31)P MR metabolic profile of these diseases differ. MATERIALS AND METHODS: 25 patients with HCV (n=12) or AIH (n=13) underwent proton decoupled (31)P MRS spectroscopy performed on a 3.0T MR imager. Intensities of phosphomonoesters (PME) of phosphoethanolamine (PE) and phosphocholine (PC), phosphodiesters (PDE) of glycerophosphoethanolamine (GPE) and glycerophosphocholine (GPC), and γ, α and β resonances of adenosine triphosphate (ATP), and nicotinamide adenine dinucleotide phosphate (NADPH) were determined...
May 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28570101/mr-elastography-demonstrates-unique-regional-brain-stiffness-patterns-in-dementias
#17
Mona ElSheikh, Arvin Arani, Avital Perry, Bradley F Boeve, Fredric B Meyer, Rodolfo Savica, Richard L Ehman, John Huston
OBJECTIVE: The purpose of this study was to investigate age-corrected brain MR elastography (MRE) findings in four dementia cohorts (Alzheimer disease, dementia with Lewy bodies, frontotemporal dementia, and normal pressure hydrocephalus) and determine the potential use as a differentiating biomarker in dementia subtypes. SUBJECTS AND METHODS: Institutional review board approval and written informed consent were obtained to perform MRE on 84 subjects: 20 patients with normal pressure hydrocephalus, eight with Alzheimer disease, five with dementia with Lewy bodies, five with frontotemporal dementia, and 46 cognitively normal control subjects...
August 2017: AJR. American Journal of Roentgenology
https://www.readbyqxmd.com/read/28558274/active-control-of-the-spatial-mri-phase-distribution-with-optimal-control-theory
#18
Pauline M Lefebvre, Eric Van Reeth, Hélène Ratiney, Olivier Beuf, Elisabeth Brusseau, Simon A Lambert, Steffen J Glaser, Dominique Sugny, Denis Grenier, Kevin Tse Ve Koon
This paper investigates the use of Optimal Control (OC) theory to design Radio-Frequency (RF) pulses that actively control the spatial distribution of the MRI magnetization phase. The RF pulses are generated through the application of the Pontryagin Maximum Principle and optimized so that the resulting transverse magnetization reproduces various non-trivial and spatial phase patterns. Two different phase patterns are defined and the resulting optimal pulses are tested both numerically with the ODIN MRI simulator and experimentally with an agar gel phantom on a 4...
May 22, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28530847/repeatability-of-mr-elastography-of-liver-a-meta-analysis
#19
Suraj D Serai, Nancy A Obuchowski, Sudhakar K Venkatesh, Claude B Sirlin, Frank H Miller, Edward Ashton, Patricia E Cole, Richard L Ehman
Purpose To perform a meta-analysis to generate an estimate of the repeatability coefficient (RC) for magnetic resonance (MR) elastography of the liver. Materials and Methods A systematic search of databases was performed for publications on MR elastography during the 10-year period between 2006 and 2015. The identified studies were screened independently and were verified reciprocally by all authors. Two reviewers independently determined the percentage RC and effective sample size from each article. A forest plot was constructed of the percentage RC estimates from the 12 studies...
October 2017: Radiology
https://www.readbyqxmd.com/read/28493802/placental-imaging-normal-appearance-with-review-of-pathologic-findings
#20
Shaimaa Fadl, Mariam Moshiri, Corinne L Fligner, Douglas S Katz, Manjiri Dighe
The placenta plays a crucial role throughout pregnancy, and its importance may be overlooked during routine antenatal imaging evaluation. Detailed systematic assessment of the placenta at ultrasonography (US), the standard imaging examination during pregnancy, is important. Familiarity with the normal and abnormal imaging appearance of the placenta along with the multimodality and methodical approach for evaluation of its related abnormalities is necessary, so that radiologists can alert clinicians regarding appropriate prompt management decisions...
May 2017: Radiographics: a Review Publication of the Radiological Society of North America, Inc
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