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Water fat imaging

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https://www.readbyqxmd.com/read/28110367/accurate-simultaneous-quantification-of-liver-steatosis-and-iron-overload-in-diffuse-liver-diseases-with-mri
#1
Manuela França, Ángel Alberich-Bayarri, Luis Martí-Bonmatí, Pedro Oliveira, Francisca Emanuel Costa, Graça Porto, José Ramón Vizcaíno, Javier Sanchez Gonzalez, Eduardo Ribeiro, João Oliveira, Helena Pessegueiro Miranda
PURPOSE: To evaluate the diagnostic performances of 3 Tesla multi-echo chemical shift-encoded gradient echo magnetic resonance (MECSE-MR) imaging to simultaneously quantify liver steatosis and iron overload in a wide spectrum of diffuse liver diseases having biopsy as reference standard. METHODS: MECSE-MR-acquired images were used to calculate fat fraction and iron content in a single breath-hold in 109 adult patients. Proton density fat fraction (PDFF) was prospectively estimated using complex-based data reconstruction with multipeak fat modeling...
January 21, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28104990/sitagliptin-in-patients-with-non-alcoholic-steatohepatitis-a-randomized-placebo-controlled-trial
#2
Tisha R Joy, Charles A McKenzie, Rommel G Tirona, Kelly Summers, Shannon Seney, Subrata Chakrabarti, Neel Malhotra, Melanie D Beaton
AIM: To evaluate the effect of sitagliptin vs placebo on histologic and non-histologic parameters of non-alcoholic steatohepatitis (NASH). METHODS: Twelve patients with biopsy-proven NASH were randomized to sitagliptin (100 mg daily) (n = 6) or placebo (n = 6) for 24 wk. The primary outcome was improvement in liver fibrosis after 24 wk. Secondary outcomes included evaluation of changes in NAFLD activity score (NAS), individual components of NAS (hepatocyte ballooning, lobular inflammation, and steatosis), glycemic control and insulin resistance [including measurements of glycated hemoglobin (HbA1C) and adipocytokines], lipid profile including free fatty acids, adipose distribution measured using magnetic resonance imaging (MRI), and thrombosis markers (platelet aggregation and plasminogen activator inhibitor 1 levels)...
January 7, 2017: World Journal of Gastroenterology: WJG
https://www.readbyqxmd.com/read/28103921/manually-defining-regions-of-interest-when-quantifying-paravertebral-muscles-fatty-infiltration-from-axial-magnetic-resonance-imaging-a-proposed-method-for-the-lumbar-spine-with-anatomical-cross-reference
#3
Rebecca J Crawford, Jon Cornwall, Rebecca Abbott, James M Elliott
BACKGROUND: There is increasing interest in paravertebral muscle composition as a potential prognostic and diagnostic element in lumbar spine health. As a consequence, it is becoming popular to use magnetic resonance imaging (MRI) to examine muscle volume and fatty infiltration in lumbar paravertebral muscles to assess both age-related change and their clinical relevance in low back pain (LBP). A variety of imaging methods exist for both measuring key variables (fat, muscle) and for defining regions of interest, making pooled comparisons between studies difficult and rendering post-production analysis of MRIs confusing...
January 19, 2017: BMC Musculoskeletal Disorders
https://www.readbyqxmd.com/read/28092409/quantification-of-brown-and-white-adipose-tissue-based-on-gaussian-mixture-model-using-water-fat-and-t2-mri-in-adolescents
#4
Steve C N Hui, Jacky K L Ko, Teng Zhang, Lin Shi, David K W Yeung, Defeng Wang, Queenie Chan, Winnie C W Chu
PURPOSE: To develop a technique for the separation and quantification of brown adipose tissue (BAT) and white adipose tissue (WAT) using fat fraction and T2* intensity based on the Gaussian mixture model (GMM). MATERIALS AND METHODS: Chemical-shift water-fat and T2* images were acquired at the neck, supraclavicular, interscapular, and paravertebral regions in 24 volunteers (Obese: n = 12, female/male = 6/6, body mass index [BMI] = 31.3 ± 2.3 kg/m(2) , age = 16...
January 16, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28074609/rapid-chemical-shift-encoding-with-single-acquisition-single-slab-3d-grase
#5
Hahnsung Kim, Dong-Hyun Kim, Chul-Ho Sohn, Jaeseok Park
PURPOSE: To investigate the feasibility of chemical shift encoded, single-slab 3D GRASE for rapid fat-water separation within a single acquisition. METHODS: The proposed method incorporates signal-to-noise-ratio-optimal chemical shift encoding into single-slab 3D GRASE with variable flip angles. Chemical shift induced phase information was encoded in succession to different positions in k-space by inserting phase encoding blips between adjacent lobes of the oscillating readout gradients...
January 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28074498/imaging-and-t2-relaxometry-of-short-t2-connective-tissues-in-the-knee-using-ultrashort-echo-time-double-echo-steady-state-utedess
#6
Akshay S Chaudhari, Bragi Sveinsson, Catherine J Moran, Emily J McWalter, Ethan M Johnson, Tao Zhang, Garry E Gold, Brian A Hargreaves
PURPOSE: To develop a radial, double-echo steady-state (DESS) sequence with ultra-short echo-time (UTE) capabilities for T2 measurement of short-T2 tissues along with simultaneous rapid, signal-to-noise ratio (SNR)-efficient, and high-isotropic-resolution morphological knee imaging. METHODS: THe 3D radial UTE readouts were incorporated into DESS, termed UTEDESS. Multiple-echo-time UTEDESS was used for performing T2 relaxometry for short-T2 tendons, ligaments, and menisci; and for Dixon water-fat imaging...
January 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28064372/effects-of-bariatric-surgery-on-non-alcoholic-fatty-liver-disease-magnetic-resonance-imaging-is-an-effective-non-invasive-method-to-evaluate-changes-in-the-liver-fat-fraction
#7
Dennis M Hedderich, Till Hasenberg, Stefan Haneder, Stefan O Schoenberg, Özlem Kücükoglu, Ali Canbay, Mirko Otto
INTRODUCTION: Non-alcoholic fatty liver disease (NAFLD) is considered the most common liver disease worldwide and is highly associated with obesity. The prevalences of both conditions have markedly increased in the Western civilization. Bariatric surgery is the most effective treatment for morbid obesity and its comorbidities such as NAFLD. OBJECTIVES: Measure postoperative liver fat fraction (LFF) in bariatric patients by using in-opposed-phase MRI, a widely available clinical tool validated for the quantification of liver fat METHODS: Retrospective analyses of participants, who underwent laparoscopic Roux-Y-gastric-bypass (17) or laparoscopic sleeve gastrectomy (2) were performed using magnetic resonance imaging (MRI), bioelectrical impedance analysis (BIA), and anthropometric measurements 1 day before surgery, as well as 6, 12, and 24 weeks after surgery, LFF was calculated from fat-only and water-only MR images...
January 7, 2017: Obesity Surgery
https://www.readbyqxmd.com/read/28060254/quantitative-magnetic-resonance-imaging-of-skeletal-muscle-disease
#8
Bruce M Damon, Ke Li, Richard D Dortch, E Brian Welch, Jane H Park, Amanda K W Buck, Theodore F Towse, Mark D Does, Daniel F Gochberg, Nathan D Bryant
Quantitative magnetic resonance imaging (qMRI) describes the development and use of MRI to quantify physical, chemical, and/or biological properties of living systems. Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multi-faceted pathology. The goal of this protocol is to characterize this pathology using qMRI methods. The MRI acquisition protocol begins with localizer images (used to locate the position of the body and tissue of interest within the MRI system), quality control measurements of relevant magnetic field distributions, and structural imaging for general anatomical characterization...
December 18, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28048911/su-g-iep1-06-estimating-relative-tissue-density-from-quantitative-mr-images-a-novel-perspective-for-mri-only-heterogeneity-corrected-dose-calculation
#9
A Soliman, M Hashemi, H Safigholi, E Tchistiakova, W Song
PURPOSE: To explore the feasibility of extracting the relative density from quantitative MRI measurements as well as estimate a correlation between the extracted measures and CT Hounsfield units. METHODS: MRI has the ability to separate water and fat signals, producing two separate images for each component. By performing appropriate corrections on the separated images, quantitative measurement of water and fat mass density can be estimated. This work aims to test this hypothesis on 1...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048790/su-f-j-112-clinical-feasibility-test-of-an-rf-pulse-based-mri-method-for-the-quantitative-fat-water-segmentation
#10
S Yee, J Wloch, M Pirkola
PURPOSE: Quantitative fat-water segmentation is important not only because of the clinical utility of fat-suppressed MRI images in better detecting lesions of clinical significance (in the midst of bright fat signal) but also because of the possible physical need, in which CT-like images based on the materials' photon attenuation properties may have to be generated from MR images; particularly, as in the case of MR-only radiation oncology environment to obtain radiation dose calculation or as in the case of hybrid PET/MR modality to obtain attenuation correction map for the quantitative PET reconstruction...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048386/th-cd-206-03-evaluation-of-a-new-method-to-improve-atlas-based-segmentation-for-the-bladder-and-rectum
#11
A Nelson, S Pirozzi, S Chung
PURPOSE: Atlas segmentation for the bladder and rectum pose particular challenges due to variability in bladder filling and variability in rectal contents including air and fecal matter. Previously we evaluated atlas segmentation for high risk prostate cancer including the bladder and rectum. In the current study we sought to further improve automated segmentation results by utilizing a customized post-processing workflow for the bladder and rectum. METHODS: Pelvic CT scans for 32 subjects with prostate cancer were chosen and the bladder and rectum were first segmented using the Multi-5 atlas-based approach described in Pirozzi et al (IJROBP 2012)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047629/su-f-j-169-a-feasibility-study-of-using-mri-alone-in-abdominal-radiotherapy
#12
I Zawisza, S Hsu, Q Peng, W Tome
PURPOSE: To demonstrate the feasibility of a MRI alone workflow to support treatment planning and image guidance for abdominal radiotherapy. METHODS: Abdominal MR images (in-phase/out-phase/fat/water) were acquired for a patient with breath-hold using a Dixon pulse sequence. Air masks were created on in-phase images using intensity thresholding and morphological processing methods in order to separate air from bone. Pseudo-CT and DRRs were generated using a published method...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047518/su-f-j-165-spectral-characterization-of-tissues-in-high-spectral-and-spatial-resolution-mr-images-in-vitro-implications-for-classification-based-synthetic-ct-algorithm
#13
A Diak, S Shea, M Surucu, S Gros, M Medved, G Karczmar, W Small, J Roeske
PURPOSE: To investigate features of spectral parameters of tissue for use in a synthetic CT algorithm. METHODS: A phantom of fresh beef leg embedded in 1% agarose gel was imaged at 1.5T on a Siemens Aero using HiSS MRI with 1.0mm resolution and 11.1Hz spectral resolution. Post-processing was performed off-line and included labeling of fat and water peaks, and fitting the spectra. All spectra were normalized by the noise within each voxel; thus all parameters are reported in units of signal-to-noise (SNR)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047476/su-f-i-16-short-breast-mri-with-high-resolution-t2-weighted-and-dynamic-contrast-enhanced-t1-weighted-images
#14
J Ma, J Son, B Arun, J Hazle, K Hwang, K Wang, E Bayram, J Madewell, W Yang, B Dogan
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...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047055/su-g-jep2-06-dosimetric-and-workflow-evaluation-of-first-commercial-synthetic-ct-software-for-clinical-use-in-pelvis
#15
N Tyagi, J Zhang, L Happersett, M Kadbi, J Mechalakos, J Deasy, M Hunt
PURPOSE: evaluate a commercial synthetic CT (syn-CT) software for use in prostate radiotherapy METHODS: Twenty prostate patients underwent CT and MR simulation scans in treatment position on a 3T Philips scanner. The MR protocol consisted of a T2w turbo spin-echo for soft tissue contrast, a 2D balanced-fast field echo (b-FFE) for fiducial identification, a dual-echo 3D FFE B0 map for distortion analysis and a 3D mDIXON FFE sequence to generate syn-CT. Two echoes are acquired during mDIXON scan, allowing water, fat, and in-phase images to be derived using the frequency shift of the fat and water protons...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046606/tu-ab-bra-01-abdominal-synthetic-ct-generation-in-support-of-liver-sbrt-dose-calculation
#16
J S Bredfeldt, L Liu, M Feng, Y Cao, J Balter
PURPOSE: To demonstrate and validate a technique for generating MRI-derived synthetic CT volumes (MRCTs) in support of adaptive liver SBRT. METHODS: Under IRB approval, ten hepatocellular carcinoma patients were scanned using a single MR sequence (T1 Dixon-VIBE), yielding inherently-registered water, fat, and T1-weighted images. Air-containing voxels were identified by intensity thresholding. The envelope of the anterior vertebral bodies was segmented from the fat image by fitting a shape model to vertebral body candidate voxels, then using level sets to expand the contour outward...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046444/su-d-207a-01-female-pelvic-synthetic-ct-generation-based-on-joint-shape-and-intensity-analysis
#17
L Liu, S Jolly, Y Cao, K Vineberg, J Fessler, J Balter
PURPOSE: To develop a method for generating female pelvic synthetic CT (MRCT) images from a single MR scan and evaluate its utility in radiotherapy. METHODS: Under IRB-approval, an imaging sequence (T1_VIBE_Dixon) was acquired for 10 patients. This sequence yields 3 useful image volumes of different contrast ("in-phase" T1-weighted, fat and water). A previously published pelvic bone shape model was used to generate a rough bone mask for each patient. A modified fuzzy c-means classification was performed on the multi spectral MR data, with a regularization term that utilizes the prior knowledge provided by the bone mask and addresses the intensity overlap between different tissue types...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28032377/proton-and-phosphorus-magnetic-resonance-spectroscopy-of-the-healthy-human-breast-at-7%C3%A2-t
#18
Wybe J M van der Kemp, Bertine L Stehouwer, Vincent O Boer, Peter R Luijten, Dennis W J Klomp, Jannie P Wijnen
In vivo water- and fat-suppressed (1) H magnetic resonance spectroscopy (MRS) and (31) P magnetic resonance adiabatic multi-echo spectroscopic imaging were performed at 7 T in duplicate in healthy fibroglandular breast tissue of a group of eight volunteers. The transverse relaxation times of (31) P metabolites were determined, and the reproducibility of (1) H and (31) P MRS was investigated. The transverse relaxation times for phosphoethanolamine (PE) and phosphocholine (PC) were fitted bi-exponentially, with an added short T2 component of 20 ms for adenosine monophosphate, resulting in values of 199 ± 8 and 239 ± 14 ms, respectively...
December 28, 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/28018735/using-drs-during-breast-conserving-surgery-identifying-robust-optical-parameters-and-influence-of-inter-patient-variation
#19
Lisanne L de Boer, Benno H W Hendriks, Frederieke van Duijnhoven, Marie-Jeanne T F D Vrancken Peeters-Baas, Koen Van de Vijver, Claudette E Loo, Katarzyna Jóźwiak, Henricus J C M Sterenborg, Theo J M Ruers
Successful breast conserving surgery consists of complete removal of the tumor while sparing healthy surrounding tissue. Despite currently available imaging and margin assessment tools, recognizing tumor tissue at a resection margin during surgery is challenging. Diffuse reflectance spectroscopy (DRS), which uses light for tissue characterization, can potentially guide surgeons to prevent tumor positive margins. However, inter-patient variation and changes in tissue physiology occurring during the resection might hamper this light-based technology...
December 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/28008425/quantitative-pet-mri-evaluation-and-application-in-dementia
#20
Yongxia Zhou
A recently introduced integrated scanner combining simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) (PET/MRI) acquisition presents a unique set of opportunities for neuroimaging research and dementia in particular [1]. Among these, the intrinsic co-registration of the images has the potential to reduce errors in multi-modality image registration, which could lead to better quantification of longitudinal volumetric changes in neuroanatomical features that are important for assessing disease progression...
June 2016: Jacobs J Med Diagn Med Imaging
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