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Magnetic Resonance Imaging

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https://www.readbyqxmd.com/read/28729016/learning-based-structurally-guided-construction-of-resting-state-functional-correlation-tensors
#1
Lichi Zhang, Han Zhang, Xiaobo Chen, Qian Wang, Pew-Thian Yap, Dinggang Shen
Functional magnetic resonance imaging (fMRI) measures changes in blood-oxygenation-level-dependent (BOLD) signals to detect brain activities. It has been recently reported that the spatial correlation patterns of resting-state BOLD signals in the white matter (WM) also give WM information often measured by diffusion tensor imaging (DTI). These correlation patterns can be captured using functional correlation tensor (FCT), which is analogous to the diffusion tensor (DT) obtained from DTI. In this paper, we propose a noise-robust FCT method aiming at further improving its quality, and making it eligible for further neuroscience study...
July 17, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28716681/mri-magic-angle-effect-in-femorotibial-cartilages-of-the-red-kangaroo
#2
Tonima S Ali, Namal Thibbotuwawa, YuanTong Gu, Konstantin I Momot
OBJECTIVE: Kangaroo knee cartilages are robust tissues that can support knee flexion and endure high levels of compressive stress. This study aimed to develop a detailed understanding of the collagen architecture in kangaroo knee cartilages and thus obtain insights into the biophysical basis of their function. DESIGN: Cylindrical/square plugs from femoral and tibial hyaline cartilage and tibial fibrocartilage were excised from the knees of three adult red kangaroos...
July 15, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28716683/trimmed-autocalibrating-k-space-estimation-based-on-structured-matrix-completion
#3
Mark Bydder, Stanislas Rapacchi, Olivier Girard, Maxime Guye, Jean-Philippe Ranjeva
PURPOSE: Parallel imaging allows the reconstruction of undersampled data from multiple coils. This provides a means to reject and regenerate corrupt data (e.g. from motion artefact). The purpose of this work is to approach this problem using the SAKE parallel imaging method. THEORY AND METHODS: Parallel imaging methods typically require calibration by fully sampling the center of k-space. This is a challenge in the presence of corrupted data, since the calibration data may be corrupted which leads to an errors-in-variables problem that cannot be solved by least squares or even iteratively reweighted least squares...
July 14, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28716682/air-mrf-accelerated-iterative-reconstruction-for-magnetic-resonance-fingerprinting
#4
Christopher C Cline, Xiao Chen, Boris Mailhe, Qiu Wang, Josef Pfeuffer, Mathias Nittka, Mark A Griswold, Peter Speier, Mariappan S Nadar
Existing approaches for reconstruction of multiparametric maps with magnetic resonance fingerprinting (MRF) are currently limited by their estimation accuracy and reconstruction time. We aimed to address these issues with a novel combination of iterative reconstruction, fingerprint compression, additional regularization, and accelerated dictionary search methods. The pipeline described here, accelerated iterative reconstruction for magnetic resonance fingerprinting (AIR-MRF), was evaluated with simulations as well as phantom and in vivo scans...
July 14, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28716680/three-dimensional-adiabatic-inversion-recovery-prepared-ultrashort-echo-time-cones-3d-ir-ute-cones-imaging-of-cortical-bone-in-the-hip
#5
Amin Nazaran, Michael Carl, Yajun Ma, Saeed Jerban, Yanchun Zhu, Xing Lu, Jiang Du, Eric Y Chang
PURPOSE: We present three-dimensional adiabatic inversion recovery prepared ultrashort echo time Cones (3D IR-UTE-Cones) imaging of cortical bone in the hip of healthy volunteers using a clinical 3T scanner. METHODS: A 3D IR-UTE-Cones sequence, based on a short pulse excitation followed by a 3D Cones trajectory, with a nominal TE of 32μs, was employed for high contrast morphological imaging of cortical bone in the hip of heathy volunteers. Signals from soft tissues such as muscle and marrow fat were suppressed via adiabatic inversion and signal nulling...
July 14, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28716679/modified-brisque-as-no-reference-image-quality-assessment-for-structural-mr-images
#6
Li Sze Chow, Heshalini Rajagopal
An effective and practical Image Quality Assessment (IQA) model is needed to assess the image quality produced from any new hardware or software in MRI. A highly competitive No Reference - IQA (NR - IQA) model called Blind/Referenceless Image Spatial Quality Evaluator (BRISQUE) initially designed for natural images were modified to evaluate structural MR images. The BRISQUE model measures the image quality by using the locally normalized luminance coefficients, which were used to calculate the image features...
July 14, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28716678/cancer-recurrence-monitoring-using-hyperpolarized-1-13-c-pyruvate-metabolic-imaging-in-murine-breast-cancer-model
#7
Peter J Shin, Zihan Zhu, Roman Camarda, Robert A Bok, Alicia Y Zhou, John Kurhanewicz, Andrei Goga, Daniel B Vigneron
The purpose of this work was to study the anatomic and metabolic changes that occur with tumor progression, regression and recurrence in a switchable MYC-driven murine breast cancer model. Serial (1)H MRI and hyperpolarized [1-(13)C]pyruvate metabolic imaging were used to investigate the changes in tumor volume and glycolytic metabolism over time during the multistage tumorigenesis. We show that acute de-induction of MYC expression in established tumors results in rapid tumor regression and significantly reduced glycolytic metabolism as measured by pyruvate-to-lactate conversion...
July 14, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28700894/preparation-of-an-au-pt-alloy-free-from-artifacts-in-magnetic-resonance-imaging
#8
Tomonobu Kodama, Ryusuke Nakai, Kenji Goto, Kunihiro Shima, Hiroo Iwata
PURPOSE: When magnetic resonance imaging (MRI) is performed on patients carrying metallic implants, artifacts can disturb the images around the implants, often making it difficult to interpret them appropriately. However, metallic materials are and will be indispensable as raw materials for medical devices because of their electric conductivity, visibility under X-ray fluoroscopy, and other favorable features. What is now desired is to develop a metallic material which causes no artifacts during MRI...
July 9, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28698004/the-effect-of-radiotherapy-on-fat-content-and-fatty-acids-in-myxoid-liposarcomas-quantified-by-mri
#9
Mikael Skorpil, Henric Rydén, Johan Wejde, Elisabet Lidbrink, Otte Brosjö, Johan Berglund
BACKGROUND: Myxoid liposarcomas are highly radiosensitive. Consequently radiotherapy is often used pre-operatively to reduce tumor volume and lessen the post-operative deficit. In soft-tissue sarcomas therapy response is mainly evaluated using magnetic resonance imaging (MRI) and the fundamental criterion for a positive response is decreased tumor size. In myxoid liposarcomas an increased fat content is also known to occur as a response to radiotherapy. OBJECTIVE: To highlight the difficulties of MRI for therapy response evaluation in irradiated myxoid liposarcomas, by using MRI Dixon techniques enabling objective quantification of proton density fat fraction (%) and the number of double bonds (ndb; unsaturation degree) of fatty acids...
July 8, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28694017/multi-frequency-interpolation-in-spiral-magnetic-resonance-fingerprinting-for-correction-of-off-resonance-blurring
#10
Jason Ostenson, Ryan K Robison, Nicholas R Zwart, E Brian Welch
Magnetic resonance fingerprinting (MRF) pulse sequences often employ spiral trajectories for data readout. Spiral k-space acquisitions are vulnerable to blurring in the spatial domain in the presence of static field off-resonance. This work describes a blurring correction algorithm for use in spiral MRF and demonstrates its effectiveness in phantom and in vivo experiments. Results show that image quality of T1 and T2 parametric maps is improved by application of this correction. This MRF correction has negligible effect on the concordance correlation coefficient and improves coefficient of variation in regions of off-resonance relative to uncorrected measurements...
July 7, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28688952/left-ventricular-mechanics-in-children-with-hypertrophic-cardiomyopathy-cmr-study
#11
Łukasz Mazurkiewicz, Lidia Ziółkowska, Joanna Petryka, Mateusz Śpiewak, Łukasz Małek, Agata Kubik, Magdalena Marczak, Jolanta Misko, Grażyna Brzezińska-Rajszys
OBJECTIVES: To assess the magnitude of myocardial displacement abnormalities and their alterations with the fibrosis, left-ventricular (LV) outflow tract obstruction (LVOTO) and hypertrophy in juveniles with hypertrophic cardiomyopathy (HCM). STUDY DESIGN: Fifty-five children [age 12,5±4.6years, 38 (69,1%) males, 19 (34,5%) with LVOTO] with HCM and 20 controls underwent cardiovascular magnetic resonance. The LV feature tracking (FT) derived strain and strain rates were quantified...
July 5, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28688951/non-contrast-enhanced-3d-mr-portography-within-a-breath-hold-using-compressed-sensing-acceleration-a-prospective-noninferiority-study
#12
Ayako Ono, Shigeki Arizono, Koji Fujimoto, Thai Akasaka, Rikiya Yamashita, Akihiro Furuta, Hiroyoshi Isoda, Kaori Togashi
PURPOSE: To evaluate images of non-contrast-enhanced 3D MR portography within a breath-hold (BH) using compressed sensing (CS) compared to standard respiratory-triggered (RT) sequences. MATERIALS AND METHODS: Fifty-nine healthy volunteers underwent MR portography using two sequences of balanced steady-state free-precession (bSSFP) with time-spatial labeling inversion pulses (Time-SLIP): BH bSSFP-CS and RT bSSFP. Two radiologists independently scored the diagnostic acceptability to delineate the portal branches (MPV: main portal vein; RPV: right portal vein; LPV: left portal vein; RPPV: right posterior portal vein; and P4 and P8: portal branch of segment 4 and segment 8, respectively) and the overall image quality on a four-point scale...
July 5, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28687216/left-ventricular-volume-measurements-with-free-breathing-respiratory-self-gated-3-dimensional-golden-angle-radial-whole-heart-cine-imaging-feasibility-and-reproducibility
#13
Karen Holst, Martin Ugander, Andreas Sigfridsson
PURPOSE: To develop and evaluate a free breathing respiratory self-gated isotropic resolution technique for left ventricular (LV) volume measurements. METHODS: A 3D radial trajectory with double golden-angle ordering was used for free-running data acquisition during free breathing in 9 healthy volunteers. A respiratory self-gating signal was extracted from the center of k-space and used with the electrocardiogram to bin all data into 3 respiratory and 25 cardiac phases...
July 5, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28684268/towards-predicting-the-encoding-capability-of-mr-fingerprinting-sequences
#14
K Sommer, T Amthor, M Doneva, P Koken, J Meineke, P Börnert
Sequence optimization and appropriate sequence selection is still an unmet need in magnetic resonance fingerprinting (MRF). The main challenge in MRF sequence design is the lack of an appropriate measure of the sequence's encoding capability. To find such a measure, three different candidates for judging the encoding capability have been investigated: local and global dot-product-based measures judging dictionary entry similarity as well as a Monte Carlo method that evaluates the noise propagation properties of an MRF sequence...
July 3, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28669751/finite-element-analysis-to-investigate-variability-of-mr-elastography-in-the-human-thigh
#15
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/28666939/magnetic-resonance-fingerprinting-with-short-relaxation-intervals
#16
Thomas Amthor, Mariya Doneva, Peter Koken, Karsten Sommer, Jakob Meineke, Peter Börnert
PURPOSE: To investigate a technique for improving the performance of Magnetic Resonance Fingerprinting (MRF) in repetitive sampling schemes, especially suited for 3D MRF acquisition, by shortening relaxation intervals between MRF pulse train repetitions. MATERIAL AND METHODS: A calculation method for MRF dictionaries adapted to short relaxation intervals and non-relaxed initial spin states is presented, based on the concept of stationary fingerprints. The method is applicable to many different k-space sampling schemes in 2D and 3D...
June 27, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28645698/radiological-studies-of-fetal-alcohol-spectrum-disorders-in-humans-and-animal-models-an-updated-comprehensive-review
#17
REVIEW
Van T Nguyen, Suyinn Chong, Quang M Tieng, Karine Mardon, Graham J Galloway, Nyoman D Kurniawan
Fetal Alcohol Spectrum Disorders encompass a wide range of birth defects in children born to mothers who consumed alcohol during pregnancy. Typical mental impairments in FASD include difficulties in life adaptation and learning and memory, deficits in attention, visuospatial skills, language and speech disabilities, mood disorders and motor disabilities. Multimodal imaging methods have enabled in vivo studies of the teratogenic effects of alcohol on the central nervous system, giving more insight into the FASD phenotype...
June 20, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28645697/clinical-high-resolution-mapping-of-the-proteoglycan-bound-water-fraction-in-articular-cartilage-of-the-human-knee-joint
#18
Mustapha Bouhrara, David A Reiter, Kyle W Sexton, Christopher M Bergeron, Linda M Zukley, Richard G Spencer
PURPOSE: We applied our recently introduced Bayesian analytic method to achieve clinically-feasible in-vivo mapping of the proteoglycan water fraction (PgWF) of human knee cartilage with improved spatial resolution and stability as compared to existing methods. MATERIALS AND METHODS: Multicomponent driven equilibrium single-pulse observation of T1 and T2 (mcDESPOT) datasets were acquired from the knees of two healthy young subjects and one older subject with previous knee injury...
June 20, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28642098/quantifying-left-atrial-structure-and-function-using-single-plane-tissue-tracking-cardiac-magnetic-resonance
#19
Susumu Tao, Luisa A Ciuffo, Joao A C Lima, Katherine C Wu, Hiroshi Ashikaga
PURPOSE: Left atrial (LA) structure and function are important markers of adverse cardiovascular outcomes. Tissue-tracking cardiovascular magnetic resonance (CMR) accurately quantifies LA volume, strain, and strain rate based on biplane long-axis imaging. We aimed to assess the accuracy of the LA indices quantification from single-plane tissue-tracking CMR. METHODS: We included 388 subjects (mean age 57±13, male 70%) whose cine CMR images in sinus rhythm were available in both four-chamber and two-chamber views: 162 patients from the Prospective Observational Study of Implantable Cardioverter-Defibrillators (PROSE-ICD) Study, 208 patients from atrial fibrillation cohort, and 18 healthy volunteers...
June 19, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28634048/activation-volume-vs-bold-signal-change-as-measures-of-fmri-activation-its-impact-on-gaba-fmri-activation-correlation
#20
Pallab K Bhattacharyya, Micheal D Phillips, Lael A Stone, Mark J Lowe
PURPOSE: To explore the relative robustness of functional MRI (fMRI) activation volume and blood oxygen level-dependent (BOLD) signal change as fMRI metric, and to study the effect of relative robustness on the correlation between fMRI activation and cortical gamma amino butyric acid (GABA) in healthy controls and patients with multiple sclerosis (MS). METHODS: fMRI data were acquired from healthy controls and patients with MS, with the subjects peforming self paced bilateral finger tapping in block design...
June 17, 2017: Magnetic Resonance Imaging
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