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https://www.readbyqxmd.com/read/28643359/an-open-8-channel-parallel-transmission-coil-for-static-and-dynamic-7t-mri-of-the-knee-and-ankle-joints-at-multiple-postures
#1
Jin Jin, Ewald Weber, Aurelien Destruel, Kieran O'Brien, Bassem Henin, Craig Engstrom, Stuart Crozier
PURPOSE: We present the initial in vivo imaging results of an open architecture eight-channel parallel transmission (pTx) transceive radiofrequency (RF) coil array that was designed and constructed for static and dynamic 7T MRI of the knee and ankle joints. METHODS: The pTx coil has a U-shaped dual-row configuration (200 mm overall length longitudinally) that allows static and dynamic imaging of the knee and ankle joints at various postures and during active movements...
June 22, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28641416/water-anion-hydrogen-bonding-dynamics-ultrafast-ir-experiments-and-simulations
#2
Steven A Yamada, Ward H Thompson, Michael D Fayer
Many of water's remarkable properties arise from its tendency to form an intricate and robust hydrogen bond network. Understanding the dynamics that govern this network is fundamental to elucidating the behavior of pure water and water in biological and physical systems. In ultrafast nonlinear infrared experiments, the accessible time scales are limited by water's rapid vibrational relaxation (1.8 ps for dilute HOD in H2O), precluding interrogation of slow hydrogen bond evolution in non-bulk systems. Here, hydrogen bonding dynamics in bulk D2O were studied from the perspective of the much longer lived (36...
June 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28639568/intraoperative-transesophageal-echocardiography-in-the-operation-of-ebstein-s-anomaly-a-retrospective-study
#3
Xiu-Jie Tang, Min Bao, He Zhao, Lian-Yi Wang, Qing-Yu Wu
BACKGROUND: Ebstein's anomaly (EA) has various spectrums in clinical and anatomic features. This study aimed to report the experience of two-dimensional intraoperative transesophageal echocardiography (2D-ITEE) during the EA surgery and to analyze the characteristics of the tricuspid valve (TV) by comparing the data from 2D-ITEE with the results from the surgery. METHODS: 2D-ITEE data of 164 patients with EA who were operated in the First Hospital of Tsinghua University between July 2004 and April 2014 were retrospectively analyzed in this study...
July 5, 2017: Chinese Medical Journal
https://www.readbyqxmd.com/read/28636512/isolated-mitral-valve-p3-prolapse-with-severe-regurgitation-transoesophageal-2d-3d-echo-guidance-in-transapical-artificial-neochordae-implantation-in-challenging-patient
#4
Katarzyna Kurnicka, Krzysztof Wrobel, Diana Zakarkaite, Andrzej Biederman, Piotr Pruszczyk
No abstract text is available yet for this article.
March 21, 2017: Acta Cardiologica
https://www.readbyqxmd.com/read/28635640/analysis-of-maneuvering-targets-with-complex-motions-by-two-dimensional-product-modified-lv-s-distribution-for-quadratic-frequency-modulation-signals
#5
Fulong Jing, Shuhong Jiao, Changbo Hou, Weijian Si, Yu Wang
For targets with complex motion, such as ships fluctuating with oceanic waves and high maneuvering airplanes, azimuth echo signals can be modeled as multicomponent quadratic frequency modulation (QFM) signals after migration compensation and phase adjustment. For the QFM signal model, the chirp rate (CR) and the quadratic chirp rate (QCR) are two important physical quantities, which need to be estimated. For multicomponent QFM signals, the cross terms create a challenge for detection, which needs to be addressed...
June 21, 2017: Sensors
https://www.readbyqxmd.com/read/28629953/3d-black-blood-mr-angiography-of-the-carotid-arteries-a-simple-sequence-for-plaque-hemorrhage-and-stenosis-evaluation
#6
Monica Sigovan, Clément Bidet, Sébastien Bros, Loic Boussel, Laura Mechtouff, Philip M Robson, Zahi A Fayad, Antoine Millon, Philippe Douek
OBJECTIVES: To evaluate the diagnostic performance of a new three-dimensional T1-weighted turbo-spin-echo sequence (3D T1-w TSE) compared to 3D contrast-enhanced angiography (CE-MRA) for stenosis measurement and compared to 2D T1-w TSE for intra-plaque hemorrhage (IPH) detection. METHODS: Eighty three patients underwent carotid MRI, using a new elliptic-centric phase encoding T1-weighted 3D TSE sequence in addition to the clinical protocol. Two observers evaluated image quality, presence of flow artifacts, and presence of intra-plaque hemorrhage, and computed the NASCET degree of stenosis for CE-MRA and for the new sequence...
June 16, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28608411/interleaved-epi-diffusion-imaging-using-spirit-based-reconstruction-with-virtual-coil-compression
#7
Zijing Dong, Fuyixue Wang, Xiaodong Ma, Zhe Zhang, Erpeng Dai, Chun Yuan, Hua Guo
PURPOSE: To develop a novel diffusion imaging reconstruction framework based on iterative self-consistent parallel imaging reconstruction (SPIRiT) for multishot interleaved echo planar imaging (iEPI), with computation acceleration by virtual coil compression. METHODS: As a general approach for autocalibrating parallel imaging, SPIRiT improves the performance of traditional generalized autocalibrating partially parallel acquisitions (GRAPPA) methods in that the formulation with self-consistency is better conditioned, suggesting SPIRiT to be a better candidate in k-space-based reconstruction...
June 12, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28597240/mr-arthrography-of-the-hip-evaluation-of-isotropic-3d-intermediate-weighted-fse-and-hybrid-gre-t1-weighted-sequences
#8
Giovanni Foti, Antonio Campacci, Michele Conati, Mirko Trentadue, Claudio Zorzi, Giovanni Carbognin
PURPOSE: To compare the diagnostic performance of three-dimensional (3D) intermediate-weighted FSE (IW-3D) and 3D hybrid T1-weighted sequences (Hy-3D) and 2D fast-spin-echo sequences (FSE) in diagnosing chondral and labral lesions at 1.5 Tesla hip MR arthrography (MRA). MATERIALS AND METHODS: Institutional review board approval was obtained and informed consent was waived. Ninety-two consecutive patients were evaluated. Chondral and labral lesions were retrospectively and independently evaluated by two radiologists...
June 9, 2017: La Radiologia Medica
https://www.readbyqxmd.com/read/28585511/three-dimensional-ultrasound-elasticity-imaging-on-an-automated-breast-volume-scanning-system
#9
Yuqi Wang, Haidy G Nasief, Sarah Kohn, Andy Milkowski, Tom Clary, Stephen Barnes, Paul E Barbone, Timothy J Hall
Ultrasound elasticity imaging has demonstrated utility in breast imaging, but it is typically performed with handheld transducers and two-dimensional imaging. Two-dimensional (2D) elastography images tissue stiffness of only a plane and hence suffers from errors due to out-of-plane motion, whereas three-dimensional (3D) data acquisition and motion tracking can be used to track out-of-plane motion that is lost in 2D elastography systems. A commercially available automated breast volume scanning system that acquires 3D ultrasound data with precisely controlled elevational movement of the 1D array ultrasound transducer was employed in this study...
June 1, 2017: Ultrasonic Imaging
https://www.readbyqxmd.com/read/28581810/coherent-two-dimensional-terahertz-magnetic-resonance-spectroscopy-of-collective-spin-waves
#10
Jian Lu, Xian Li, Harold Y Hwang, Benjamin K Ofori-Okai, Takayuki Kurihara, Tohru Suemoto, Keith A Nelson
We report a demonstration of two-dimensional (2D) terahertz (THz) magnetic resonance spectroscopy using the magnetic fields of two time-delayed THz pulses. We apply the methodology to directly reveal the nonlinear responses of collective spin waves (magnons) in a canted antiferromagnetic crystal. The 2D THz spectra show all of the third-order nonlinear magnon signals including magnon spin echoes, and 2-quantum signals that reveal pairwise correlations between magnons at the Brillouin zone center. We also observe second-order nonlinear magnon signals showing resonance-enhanced second-harmonic and difference-frequency generation...
May 19, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28580842/understanding-magnetic-resonance-imaging-of-knee-cartilage-repair-a-focus-on-clinical-relevance
#11
Daichi Hayashi, Xinning Li, Akira M Murakami, Frank W Roemer, Siegfried Trattnig, Ali Guermazi
The aims of this review article are (a) to describe the principles of morphologic and compositional magnetic resonance imaging (MRI) techniques relevant for the imaging of knee cartilage repair surgery and their application to longitudinal studies and (b) to illustrate the clinical relevance of pre- and postsurgical MRI with correlation to intraoperative images. First, MRI sequences that can be applied for imaging of cartilage repair tissue in the knee are described, focusing on comparison of 2D and 3D fast spin echo and gradient recalled echo sequences...
June 1, 2017: Cartilage
https://www.readbyqxmd.com/read/28579307/tricuspid-annular-plane-systolic-excursion-in-dogs-with-myxomatous-mitral-valve-disease-with-and-without-pulmonary-hypertension
#12
H Poser, M Berlanda, M Monacolli, B Contiero, A Coltro, C Guglielmini
OBJECTIVES: To evaluate tricuspid annular plane systolic excursion (TAPSE) in dogs with myxomatous mitral valve disease (MMVD) with or without pulmonary hypertension (PH) and to study the correlations with clinical and echocardiographic parameters. ANIMALS: The study population included 99 dogs with MMVD and tricuspid regurgitation. METHODS: This is a prospective clinical study. All dogs received a transthoracic echocardiographic evaluation, including 2D, M-mode, echo-Doppler, and tissue Doppler measurements...
June 1, 2017: Journal of Veterinary Cardiology: the Official Journal of the European Society of Veterinary Cardiology
https://www.readbyqxmd.com/read/28573718/automatic-detection-of-end-diastolic-and-end-systolic-frames-in-2d-echocardiography
#13
Massoud Zolgharni, Madalina Negoita, Niti M Dhutia, Michael Mielewczik, Karikaran Manoharan, S M Afzal Sohaib, Judith A Finegold, Stefania Sacchi, Graham D Cole, Darrel P Francis
BACKGROUND: Correctly selecting the end-diastolic and end-systolic frames on a 2D echocardiogram is important and challenging, for both human experts and automated algorithms. Manual selection is time-consuming and subject to uncertainty, and may affect the results obtained, especially for advanced measurements such as myocardial strain. METHODS AND RESULTS: We developed and evaluated algorithms which can automatically extract global and regional cardiac velocity, and identify end-diastolic and end-systolic frames...
June 1, 2017: Echocardiography
https://www.readbyqxmd.com/read/28560152/improved-cerebral-microbleeds-detection-using-their-magnetic-signature-on-t2-phase-contrast-a-comparison-study-in-a-clinical-setting
#14
Takoua Kaaouana, Anne Bertrand, Fatma Ouamer, Bruno Law-Ye, Nadya Pyatigorskaya, Ali Bouyahia, Nathalie Thiery, Carole Dufouil, Christine Delmaire, Didier Dormont, Ludovic de Rochefort, Marie Chupin
INTRODUCTION/PURPOSE: In vivo detection of cerebral microbleeds (CMBs) from T2* gradient recalled echo (GRE) magnitude image suffers from low specificity, modest inter-rater reproducibility and is biased by its sensitivity to acquisition parameters. New methods were proposed for improving this identification, but they mostly rely on 3D acquisitions, not always feasible in clinical practice. A fast 2D phase processing technique for computing internal field maps (IFM) has been shown to make it possible to characterize CMBs through their magnetic signature in routine clinical setting, based on 2D multi-slice acquisitions...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28551397/automated-t2-mapping-of-the-menisci-from-magnetic-resonance-images-in-patients-with-acute-knee-injury
#15
Anthony Paproki, Craig Engstrom, Mark Strudwick, Katharine J Wilson, Rachel K Surowiec, Charles Ho, Stuart Crozier, Jurgen Fripp
RATIONALE AND OBJECTIVES: This study aimed to evaluate the accuracy of an automated method for segmentation and T2 mapping of the medial meniscus (MM) and lateral meniscus (LM) in clinical magnetic resonance images from patients with acute knee injury. MATERIALS AND METHODS: Eighty patients scheduled for surgery of an anterior cruciate ligament or meniscal injury underwent magnetic resonance imaging of the knee (multiplanar two-dimensional [2D] turbo spin echo [TSE] or three-dimensional [3D]-TSE examinations, T2 mapping)...
May 24, 2017: Academic Radiology
https://www.readbyqxmd.com/read/28534200/atrophy-of-calf-muscles-by-unloading-results-in-an-increase-of-tissue-sodium-concentration-and-fat-fraction-decrease-a-23-na-mri-physiology-study
#16
D A Gerlach, K Schopen, P Linz, B Johannes, J Titze, J Zange, J Rittweger
PURPOSE: (23)Na MRI demonstrated increased tissue sodium concentrations in a number of pathologies. Acute atrophy results in muscle fibre volume shrinking that may result in a relative increase of extracellular volume and might affect sodium concentration. Thus, we hypothesized that local unloading of the calf muscles would lead to a decrease in muscle volume and an increase in muscle tissue sodium concentration. METHOD: One lower leg of 12 healthy male subjects was submitted to a 60 day long period of unloading using the Hephaistos orthosis, while the other leg served as control...
May 22, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28528267/using-mri-to-non-invasively-and-accurately-quantify-preoperative-hepatic-steatosis
#17
Callisia N Clarke, Haesun Choi, Ping Hou, Catherine H Davis, Jingfei Ma, Asif Rashid, Jean-Nicolas Vauthey, Thomas A Aloia
BACKGROUND: The obesity epidemic has significantly increased the incidence and severity of hepatic steatosis in liver surgery patients and liver donors, potentially impacting postoperative liver regeneration and function. Development of a non-invasive means to quantify hepatic steatosis would facilitate selection of candidates for liver resection and transplant donation. METHODS: An IRB-approved protocol prospectively enrolled 28 patients with liver tumors requiring hepatic resection...
May 17, 2017: HPB: the Official Journal of the International Hepato Pancreato Biliary Association
https://www.readbyqxmd.com/read/28524543/snapshot-whole-brain-t1-relaxometry-using-steady-state-prepared-spiral-multislice-variable-flip-angle-imaging
#18
Rahel Heule, Josef Pfeuffer, Oliver Bieri
PURPOSE: Variable flip angle (VFA) imaging is widely used for whole-brain T1 quantification. Because of the requirement to acquire at least two sets of MR images at different flip angles, VFA relaxometry is relatively slow. Here, whole-brain VFA T1 mapping at 1.5 T is accelerated by using efficient spiral non-Cartesian imaging METHODS: To quantify T1 in the human brain, radiofrequency spoiled gradient-echo imaging is performed at two optimized flip angles using an interleaved 2D multislice sequence with high spoiling efficiency...
May 19, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28513892/assessment-of-nonarteritic-anterior-ischemic-optic-neuropathy-with-intravoxel-incoherent-motion-diffusion-weighted-imaging-using-readout-segmented-echo-planar-imaging-parallel-imaging-and-2d-navigator-based-reacquisition
#19
Ping Lu, Yan Sha, Hailin Wan, Feng Wang, Guohong Tan, Wenlin Tang
PURPOSE: To determine the feasibility of intravoxel incoherent motion (IVIM) for characterizing perfusion properties and its potential diagnostic utility for nonarteritic anterior ischemic optic neuropathy (NAION). IVIM diffusion-weighted imaging is a promising technique that can measure perfusion and diffusion characteristics simultaneously in a noninvasive manner. MATERIALS AND METHODS: Orbital IVIM in a 3.0T scanner was performed on 33 patients with NAION and 15 controls using readout-segmented echo-planar imaging, parallel imaging, and 2D navigator-based reacquisition (RESOLVE-IVIM)...
May 17, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28491295/magnetic-resonance-imaging-planning-in-children-with-complex-congenital-heart-disease-a-new-approach
#20
Israel Valverde, Tarinee Tangcharoen, Tarique Hussain, Hubrecht de Bliek, Graeme Penney, Marcel Breeuwer, Tobias Schaeffter, Reza Razavi, Gerald Greil
OBJECTIVES: To compare a standard sequential 2D Planning Method (2D-PM) with a 3D offline Planning Method (3D-PM) based on 3D contrast-enhanced magnetic resonance angiography (CE-MRA) in children with congenital heart disease (CHD). DESIGN: In 14 children with complex CHD (mean: 2.6 years, range: 3 months to 7.6 years), axial and coronal cuts were obtained with single slice spin echo sequences to get the final double oblique longitudinal cut of the targeted anatomical structure (2D-PM, n = 31)...
January 2017: JRSM Cardiovascular Disease
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