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Magma

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https://www.readbyqxmd.com/read/27844220/respiratory-optimized-data-selection-for-more-resilient-self-navigated-whole-heart-coronary-mr-angiography
#1
Jerome Chaptinel, Davide Piccini, Gabriele Bonanno, Simone Coppo, Pierre Monney, Matthias Stuber, Juerg Schwitter
OBJECTIVES: Our objective was to test a data-exclusion strategy for respiratory motion suppression by retrospectively eliminating data acquired at extreme respiratory positions for improved coronary vessel sharpness (VS) of 1-D self-navigated 3-D radial whole-heart coronary angiography acquisitions. MATERIALS AND METHODS: 3-D radial self-navigated acquisitions were performed on a 1.5T scanner in volunteers during free-breathing (n = 8), in coached volunteers (n = 13) who were asked to breathe in a controlled manner to mimic cardiovascular patients presenting with Cheyne-Stokes breathing, and in free-breathing patients (n = 20)...
November 14, 2016: Magma
https://www.readbyqxmd.com/read/27822656/k-space-data-processing-for-magnetic-resonance-elastography-mre
#2
Nadège Corbin, Elodie Breton, Michel de Mathelin, Jonathan Vappou
OBJECTIVE: Magnetic resonance elastography (MRE) requires substantial data processing based on phase image reconstruction, wave enhancement, and inverse problem solving. The objective of this study is to propose a new, fast MRE method based on MR raw data processing, particularly adapted to applications requiring fast MRE measurement or high elastogram update rate. MATERIALS AND METHODS: The proposed method allows measuring tissue elasticity directly from raw data without prior phase image reconstruction and without phase unwrapping...
November 7, 2016: Magma
https://www.readbyqxmd.com/read/27822655/accelerating-multi-echo-water-fat-mri-with-a-joint-locally-low-rank-and-spatial-sparsity-promoting-reconstruction
#3
Felix Lugauer, Dominik Nickel, Jens Wetzl, Berthold Kiefer, Joachim Hornegger, Andreas Maier
OBJECTIVES: Our aim was to demonstrate the benefits of using locally low-rank (LLR) regularization for the compressed sensing reconstruction of highly-accelerated quantitative water-fat MRI, and to validate fat fraction (FF) and [Formula: see text] relaxation against reference parallel imaging in the abdomen. MATERIALS AND METHODS: Reconstructions using spatial sparsity regularization (SSR) were compared to reconstructions with LLR and the combination of both (LLR+SSR) for up to seven fold accelerated 3-D bipolar multi-echo GRE imaging...
November 7, 2016: Magma
https://www.readbyqxmd.com/read/27815649/magnetic-resonance-imaging-detection-of-multiple-ischemic-injury-produced-in-an-adult-rat-model-of-minor-stroke-followed-by-mild-transient-cerebral-ischemia
#4
Ursula I Tuor, Min Qiao
OBJECTIVES: To determine whether cumulative brain damage produced adjacent to a minor stroke that is followed by a mild transient ischemia is detectable with MRI and histology, and whether acute or chronic recovery between insults influences this damage. MATERIALS AND METHODS: A minor photothrombotic (PT) stroke was followed acutely (1-2 days) or chronically (7 days) by a mild transient middle cerebral artery occlusion (tMCAO). MRI was performed after each insult, followed by final histology...
November 4, 2016: Magma
https://www.readbyqxmd.com/read/27787676/insight-into-the-labeling-mechanism-of-acceleration-selective-arterial-spin-labeling
#5
Sophie Schmid, Esben T Petersen, Matthias J P Van Osch
OBJECTIVES: Acceleration selective arterial spin labeling (AccASL) is a spatially non-selective labeling technique, used in traditional ASL methods, which labels spins based on their flow acceleration rather than spatial localization. The exact origin of the AccASL signal within the vasculature is not completely understood. To obtain more insight into this, the acceleration selective module was performed followed by a velocity selective module, which is used in velocity selective arterial spin labeling (VS-ASL)...
October 27, 2016: Magma
https://www.readbyqxmd.com/read/27785640/can-mri-t1-be-used-to-detect-early-changes-in-5xfad-alzheimer-s-mouse-brain
#6
Nicholas G Spencer, David P Lovell, Kay Elderfield, Brian Austen, Franklyn A Howe
OBJECTIVES: In the present study, we have tested whether MRI T1 relaxation time is a sensitive marker to detect early stages of amyloidosis and gliosis in the young 5xFAD transgenic mouse, a well-established animal model for Alzheimer's disease. MATERIALS AND METHODS: 5xFAD and wild-type mice were imaged in a 4.7 T Varian horizontal bore MRI system to generate T1 quantitative maps using the spin-echo multi-slice sequence. Following immunostaining for glial fibrillary acidic protein, Iba-1, and amyloid-β, T1 and area fraction of staining were quantified in the posterior parietal and primary somatosensory cortex and corpus callosum...
October 26, 2016: Magma
https://www.readbyqxmd.com/read/27734163/erratum-to-thin-film-based-semi-active-resonant-marker-design-for-low-profile-interventional-cardiovascular-mri-devices
#7
Engin Baysoy, Dursun Korel Yildirim, Cagla Ozsoy, Senol Mutlu, Ozgur Kocaturk
No abstract text is available yet for this article.
October 12, 2016: Magma
https://www.readbyqxmd.com/read/27687624/reproducibility-of-locus-coeruleus-and-substantia-nigra-imaging-with-neuromelanin-sensitive-mri
#8
Jason Langley, Daniel E Huddleston, Christine J Liu, Xiaoping Hu
OBJECTIVES: The purpose of this study was to assess the reproducibility of substantia nigra pars compacta (SNpc) and locus coeruleus (LC) delineation and measurement with neuromelanin-sensitive MRI. MATERIALS AND METHODS: Eleven subjects underwent two neuromelanin-sensitive MRI scans. SNpc and LC volumes were extracted for each scan. Reproducibility of volume and magnetization transfer contrast measurements in SNpc and LC was assessed using intraclass correlation coefficients (ICC) and dice similarity coefficients (DSC)...
September 29, 2016: Magma
https://www.readbyqxmd.com/read/27670762/a-comparison-of-fitting-algorithms-for-diffusion-weighted-mri-data-analysis-using-an-intravoxel-incoherent-motion-model
#9
Roberta Fusco, Mario Sansone, Antonella Petrillo
OBJECT: The objective of this study is to propose a modified VARiable PROjection (VARPRO) algorithm specifically tailored for fitting the intravoxel incoherent motion (IVIM) model to diffusion-weighted magnetic resonance imaging (DW-MRI) data from locally advanced rectal cancer (LARC). MATERIALS AND METHODS: The proposed algorithm is compared with classical non-linear least squares (NLLS) analysis using the Levenberg-Marquardt (LM) algorithm and with two recently proposed algorithms for 'segmented' analysis...
September 26, 2016: Magma
https://www.readbyqxmd.com/read/27638089/comparison-of-t1-weighted-2d-tse-3d-spgr-and-two-point-3d-dixon-mri-for-automated-segmentation-of-visceral-adipose-tissue-at-3-tesla
#10
Faezeh Fallah, Jürgen Machann, Petros Martirosian, Fabian Bamberg, Fritz Schick, Bin Yang
OBJECTIVES: To evaluate and compare conventional T1-weighted 2D turbo spin echo (TSE), T1-weighted 3D volumetric interpolated breath-hold examination (VIBE), and two-point 3D Dixon-VIBE sequences for automatic segmentation of visceral adipose tissue (VAT) volume at 3 Tesla by measuring and compensating for errors arising from intensity nonuniformity (INU) and partial volume effects (PVE). MATERIALS AND METHODS: The body trunks of 28 volunteers with body mass index values ranging from 18 to 41...
September 16, 2016: Magma
https://www.readbyqxmd.com/read/27624474/non-gadolinium-dynamic-angiography-of-the-neurovasculature-using-arterial-spin-labeling-mri-preliminary-experience-in-children
#11
Houchun H Hu, Amber L Pokorney, Niccolo Stefani, Jonathan M Chia, Jeffrey H Miller
OBJECTIVE: We demonstrate the potential clinical utility of a 4D non-gadolinium dynamic angiography technique based on arterial spin-labeling called contrast inherent inflow enhanced multi-phase angiography (CINEMA) in pediatric patients. MATERIALS AND METHODS: CINEMA was qualitatively compared to conventional time-of-flight (TOF) angiography in a cohort of 31 pediatric patients at 3 Tesla. RESULTS: CINEMA data were successfully acquired and reconstructed in all patients with no image artifacts...
September 13, 2016: Magma
https://www.readbyqxmd.com/read/27624473/dynamic-dti-ddti-shows-differing-temporal-activation-patterns-in-post-exercise-skeletal-muscles
#12
Conrad Rockel, Alireza Akbari, Dinesh A Kumbhare, Michael D Noseworthy
OBJECT: To assess post-exercise recovery of human calf muscles using dynamic diffusion tensor imaging (dDTI). MATERIALS AND METHODS: DTI data (6 directions, b = 0 and 400 s/mm(2)) were acquired every 35 s from seven healthy men using a 3T MRI, prior to (4 volumes) and immediately following exercise (13 volumes, ~7.5 min). Exercise consisted of 5-min in-bore repetitive dorsiflexion-eversion foot motion with 0.78 kg resistance. Diffusion tensors calculated at each time point produced maps of mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity (RD), and signal at b = 0 s/mm(2) (S0)...
September 13, 2016: Magma
https://www.readbyqxmd.com/read/27160300/a-novel-alternative-to-classify-tissues-from-t-1-and-t-2-relaxation-times-for-prostate-mri
#13
Jorge Zavala Bojorquez, Stéphanie Bricq, François Brunotte, Paul M Walker, Alain Lalande
OBJECTIVE: To segment and classify the different attenuation regions from MRI at the pelvis level using the T 1 and T 2 relaxation times and anatomical knowledge as a first step towards the creation of PET/MR attenuation maps. MATERIALS AND METHODS: Relaxation times were calculated by fitting the pixel-wise intensities of acquired T 1- and T 2-weighted images from eight men with inversion-recovery and multi-echo multi-slice spin-echo sequences. A decision binary tree based on relaxation times was implemented to segment and classify fat, muscle, prostate, and air (within the body)...
October 2016: Magma
https://www.readbyqxmd.com/read/27097906/glioma-vessel-abnormality-quantification-using-time-of-flight-mr-angiography
#14
Maddalena Strumia, Wilfried Reichardt, Ori Staszewski, Dieter Henrik Heiland, Astrid Weyerbrock, Irina Mader, Michael Bock
OBJECTIVES: To differentiate between abnormal tumor vessels and regular brain vasculature using new quantitative measures in time-of-flight (TOF) MR angiography (MRA) data. MATERIALS AND METHODS: In this work time-of-flight (TOF) MR angiography data are acquired in 11 glioma patients to quantify vessel abnormality. Brain vessels are first segmented with a new algorithm, efficient monte-carlo image-analysis for the location of vascular entity (EMILOVE), and are then characterized in three brain regions: tumor, normal-appearing contralateral brain, and the total brain volume without the tumor...
October 2016: Magma
https://www.readbyqxmd.com/read/27094553/intravoxel-incoherent-motion-analysis-of-abdominal-organs-computation-of-reference-parameters-in-a-large-cohort-of-c57bl-6-mice-and-correlation-to-microvessel-density
#15
Christian Eberhardt, Moritz C Wurnig, Andrea Wirsching, Cristina Rossi, Markus Rottmar, Pinar S Özbay, Lukas Filli, Mickael Lesurtel, Andreas Boss
OBJECTIVE: Diffusion-weighted magnetic resonance imaging (DW-MRI) combined with intravoxel incoherent motion (IVIM) analysis may be applied for assessment of organ lesions, diffuse parenchymal pathologies, and therapy monitoring. The aim of this study was to determine IVIM reference parameters of abdominal organs for translational research in a large cohort of C57Bl/6 laboratory mice. MATERIALS AND METHODS: Anesthetized mice (n = 29) were measured in a 4.7 T small-animal MR scanner with a diffusion-weighted echo-planar imaging sequence at the [Formula: see text]-values 0, 13, 24, 55, 107, 260, 514, 767, 1020 s/mm(2)...
October 2016: Magma
https://www.readbyqxmd.com/read/27038935/scan-time-minimization-in-hepatic-diffusion-weighted-imaging-evaluation-of-the-simultaneous-multislice-acceleration-technique-with-different-acceleration-factors-and-gradient-preparation-schemes
#16
Jana Taron, Petros Martirosian, Nina F Schwenzer, Michael Erb, Thomas Kuestner, Jakob Weiß, Ahmed Othman, Mike Notohamiprodjo, Konstantin Nikolaou, Christina Schraml
OBJECTIVE: To evaluate simultaneous multislice (sms) accelerated diffusion-weighted imaging (DWI) of the liver in comparison to conventional sequences. MATERIALS AND METHODS: Ten volunteers underwent DWI of the liver at 1.5 T. Four different sms-accelerated sequences with monopolar and bipolar gradient preparation (MP, BP) and acceleration factors 2 and 3 (sms2-DWI, sms3-DWI) were compared to conventional DWI (c-DWI). Image quality criteria rated on a 5-point Likert scale (5 = excellent), image quality sum scores (maximum 120), and ADC were compared using Friedman test and Dunn-Bonferroni post hoc test...
October 2016: Magma
https://www.readbyqxmd.com/read/27038934/coronary-mr-angiography-at-3t-fat-suppression-versus-water-fat-separation
#17
Maryam Nezafat, Markus Henningsson, David P Ripley, Nathalie Dedieu, Gerald Greil, John P Greenwood, Peter Börnert, Sven Plein, René M Botnar
OBJECTIVES: To compare Dixon water-fat suppression with spectral pre-saturation with inversion recovery (SPIR) at 3T for coronary magnetic resonance angiography (MRA) and to demonstrate the feasibility of fat suppressed coronary MRA at 3T without administration of a contrast agent. MATERIALS AND METHODS: Coronary MRA with Dixon water-fat separation or with SPIR fat suppression was compared on a 3T scanner equipped with a 32-channel cardiac receiver coil. Eight healthy volunteers were examined...
October 2016: Magma
https://www.readbyqxmd.com/read/27026244/automated-assessment-of-thigh-composition-using-machine-learning-for-dixon-magnetic-resonance-images
#18
Yu Xin Yang, Mei Sian Chong, Laura Tay, Suzanne Yew, Audrey Yeo, Cher Heng Tan
OBJECTIVES: To develop and validate a machine learning based automated segmentation method that jointly analyzes the four contrasts provided by Dixon MRI technique for improved thigh composition segmentation accuracy. MATERIALS AND METHODS: The automatic detection of body composition is formulized as a three-class classification issue. Each image voxel in the training dataset is assigned with a correct label. A voxel classifier is trained and subsequently used to predict unseen data...
October 2016: Magma
https://www.readbyqxmd.com/read/27605033/thin-film-based-semi-active-resonant-marker-design-for-low-profile-interventional-cardiovascular-mri-devices
#19
Engin Baysoy, Dursun Korel Yildirim, Cagla Ozsoy, Senol Mutlu, Ozgur Kocaturk
OBJECTIVES: A new microfabrication method to produce low profile radio frequency (RF) resonant markers on catheter shafts was developed. A semi-active RF resonant marker incorporating a solenoid and a plate capacitor was constructed on the distal shaft of a 5 Fr guiding catheter. The resulting device can be used for interventional cardiovascular MRI procedures. MATERIALS AND METHODS: Unlike current semi-active device visualization techniques that require rigid and bulky analog circuit components (capacitor and solenoid), we fabricated a low profile RF resonant marker directly on guiding the catheter surface by thin film metal deposition and electroplating processes using a modified physical vapor deposition system...
September 7, 2016: Magma
https://www.readbyqxmd.com/read/27645226/esmrmb-2016-33rd-annual-scientific-meeting-vienna-at-september-29-october-1-author-index
#20
(no author information available yet)
No abstract text is available yet for this article.
September 2016: Magma
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