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Phase contrast Magnetic

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https://www.readbyqxmd.com/read/28066805/evaluation-of-soft-tissue-sarcoma-response-to-preoperative-chemoradiotherapy-using-dynamic-contrast-enhanced-magnetic-resonance-imaging
#1
Wei Huang, Brooke R Beckett, Alina Tudorica, Janelle M Meyer, Aneela Afzal, Yiyi Chen, Atiya Mansoor, James B Hayden, Yee-Cheen Doung, Arthur Y Hung, Megan L Holtorf, Torrie J Aston, Christopher W Ryan
This study aims to assess the utility of quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters in comparison with imaging tumor size for early prediction and evaluation of soft tissue sarcoma response to preoperative chemoradiotherapy. In total, 20 patients with intermediate- to high-grade soft tissue sarcomas received either a phase I trial regimen of sorafenib + chemoradiotherapy (n = 8) or chemoradiotherapy only (n = 12), and underwent DCE-MRI at baseline, after 2 weeks of treatment with sorafenib or after the first chemotherapy cycle, and after therapy completion...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28065695/perfusion-of-the-uterine-junctional-zone-in-nulliparous-and-primiparous-women-assessed-by-dce-mri-as-a-function-of-menstrual-cycle-and-hormonal-contraception
#2
L J Meylaerts, L Wijnen, M Bazot, M Grieten, W Ombelet, M Vandersteen
PURPOSE: To evaluate the perfusion parameters of inner and outer myometrium in healthy nulliparous and primiparous women who are and who are not currently using hormonal contraceptives by means of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). MATERIAL AND METHODS: We performed pelvic 1.5T DCE-MRI on 98 women: 18 nulliparous non-users, 30 nulliparous users, 12 primiparous non-users and 38 primiparous users of hormonal contraception (mean age respectively 26...
January 6, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28065382/energy-efficiency-and-pulmonary-artery-flow-after-balloon-pulmonary-angioplasty-for-inoperable-chronic-thromboembolic-pulmonary-hypertension-analysis-by-phase-contrast-mri
#3
Michinobu Nagao, Yuzo Yamasaki, Kohtaro Abe, Kazuya Hosokawa, Satoshi Kawanami, Takeshi Kamitani, Torahiko Yamanouchi, Hidetake Yabuuchi, Kenji Fukushima, Hiroshi Honda
PURPOSE: The aims of this study were to propose a new quantitative method for pulmonary artery (PA) flow energetics using phase-contrast magnetic resonance imaging (PC-MRI), and to investigate how balloon pulmonary angioplasty (BPA) impacts energetics in chronic thromboembolic pulmonary hypertension (CTEPH). MATERIALS AND METHODS: PC-MRI at 3-Teslar and with a flow sensitive gradient echo was used to examine energetics prior to and following BPA for 24 CTEPH patients...
February 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28065166/the-predictive-capabilities-of-a-novel-cardiovascular-magnetic-resonance-derived-marker-of-cardiopulmonary-reserve-on-established-prognostic-surrogate-markers-in-patients-with-pulmonary-vascular-disease-results-of-a-longitudinal-pilot-study
#4
Timothy J Baillie, Samuel Sidharta, Peter M Steele, Stephen G Worthley, Scott Willoughby, Karen Teo, Prashanthan Sanders, Stephen J Nicholls, Matthew I Worthley
BACKGROUND: No unified method exists to effectively predict and monitor progression of pulmonary arterial hypertension (PAH). We assessed the longitudinal relationship between a novel marker of cardiopulmonary reserve and established prognostic surrogate markers in patients with pulmonary vascular disease. METHODS AND RESULTS: Twenty participants with confirmed (n = 14) or at high risk (n = 6) for PAH underwent cardiovascular magnetic resonance (CMR) at baseline and after ~6 months of guideline-appropriate management...
January 9, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28063459/cardiac-remodeling-following-reperfused-acute-myocardial-infarction-is-linked-to-the-concomitant-evolution-of-vascular-function-as-assessed-by-cardiovascular-magnetic-resonance
#5
Olivier Huttin, Damien Mandry, Romain Eschalier, Lin Zhang, Emilien Micard, Freddy Odille, Marine Beaumont, Renaud Fay, Jacques Felblinger, Edoardo Camenzind, Faïez Zannad, Nicolas Girerd, Pierre Y Marie
BACKGROUND: Left ventricular (LV) remodeling following acute myocardial infarction (MI) is difficult to predict at an individual level although a possible interfering role of vascular function has yet to be considered to date. This study aimed to determine the extent to which this LV remodeling is influenced by the concomitant evolution of vascular function and LV loading conditions, as assessed by phase-contrast Cardiovascular Magnetic Resonance (CMR) of the ascending aorta. METHODS: CMR was performed in 121 patients, 2-4 days after reperfusion of a first ST-segment elevation myocardial infarction and 6 months thereafter...
January 4, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28063406/contemporary-imaging-of-incidentally-discovered-adrenal-masses
#6
REVIEW
Daniel J Wale, Ka Kit Wong, Benjamin L Viglianti, Domenico Rubello, Milton D Gross
Adrenal lesions are routinely encountered incidentally in clinical practice. Although most of these lesions are benign, malignancy needs to be excluded. Therefore, the initial clinical workup is to exclude aggressive characteristics suggesting malignancy and to identify characteristics predictive of the most common benign lesion, an adrenal adenoma. Predicting a benign adenoma using a variety of imaging modalities has been widely studied using unenhanced computed tomography (CT), contrast enhanced CT, and magnetic resonance (MR) imaging...
January 4, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28061002/closed-form-expressions-for-flip-angle-variation-that-maximize-total-signal-in-t1-weighted-rapid-gradient-echo-mri
#7
Matthias Drobnitzky, Uwe Klose
PURPOSE: Magnetization-prepared rapid gradient-echo (MPRAGE) sequences are commonly employed for T1-weighted structural brain imaging. Following a contrast preparation radiofrequency (RF) pulse the data acquisition proceeds under non-equilibrium conditions of the relaxing longitudinal magnetization. Variation of the flip angle can be used to maximize total available signal. Simulated annealing or greedy algorithms have so far been published to numerically solve this problem, with signal to noise ratios optimized for clinical imaging scenarios by adhering to a predefined shape of the signal evolution...
January 6, 2017: Medical Physics
https://www.readbyqxmd.com/read/28060492/tetragonal-to-cubic-transformation-of-sio2-stabilized-zro2-polymorph-through-dysprosium-substitutions
#8
Subramaniyan Vasanthavel, Brian Derby, Sanjeevi Kannan
Partially stabilized tetragonal zirconia (t-ZrO2) is of particular interest for hard tissue replacements. Aging-related failures of the ceramic associated with the gradual transformation from t-ZrO2 to m-ZrO2 (monoclinic zirconia) can lead to its premature removal from the implant site. In addition, monitoring the satisfactory performance of the implant throughout its lifespan without invasive techniques is a challenging task. The magnetic resonance imaging (MRI) contrast ability of dysprosium (Dy(3+)) is well-established...
January 6, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28059854/perforator-phase-contrast-angiography-of-deep-inferior-epigastric-perforators-a-better-preoperative-imaging-tool-for-flap-surgery-than-computed-tomographic-angiography
#9
Xiangyu Yang, Michael J Miller, Harry T Friel, Allison Slijepcevic, Michael V Knopp
OBJECTIVE: The aim of this study was to demonstrate the feasibility of in vivo perforator visualization by a newly proposed magnetic resonance-based perforator phase contrast angiography (pPCA) technique for deep inferior epigastric perforator (DIEP) flap surgery and to prospectively compare its image quality and clinical value with computed tomographic angiography (CTA), the state-of-the-art perforator imaging technique. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained...
January 4, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28058480/everyman-s-prostate-phantom-kiwi-fruit-substitute-for-human-prostates-at-magnetic-resonance-imaging-diffusion-weighted-imaging-and-magnetic-resonance-spectroscopy
#10
Ullrich G Mueller-Lisse, Sophie Murer, Ulrike L Mueller-Lisse, Marissa Kuhn, Juergen Scheidler, Michael Scherr
OBJECTIVES: To apply an easy-to-assemble phantom substitute for human prostates in T2-weighted magnetic resonance imaging (T2WI), diffusion-weighted imaging (DWI) and 3D magnetic resonance spectroscopy (MRS). METHODS: Kiwi fruit were fixed with gel hot and cold compress packs on two plastic nursery pots, separated by a plastic plate, and submerged in tap water inside a 1-L open-spout plastic watering can for T2WI (TR/TE 7500/101 ms), DWI (5500/61 ms, ADC b50-800 s/mm(2) map) and MRS (940/145 ms) at 3...
January 5, 2017: European Radiology
https://www.readbyqxmd.com/read/28050234/how-to-assess-the-efficacy-or-failure-of-targeted-therapy-deciding-when-to-stop-sorafenib-in-hepatocellular-carcinoma
#11
REVIEW
Jean-Luc Raoul, Xavier Adhoute, Marine Gilabert, Julien Edeline
Sorafenib is thus far the only systemic treatment for hepatocellular carcinoma (HCC) based on the results of two randomized controlled trials performed in Western and in Eastern countries, despite a poor response rate (from 2% to 3.3%) following conventional evaluation criteria. It is now recognized that the criteria (European Association of the Study of the Liver criteria, modified response evaluation criteria in solid tumors) based on contrast enhanced techniques (computed tomography scan, magnetic resonance imaging) aimed to assess the evolution of the viable part of the tumor (hypervascularized on arterial phase) are of major interest to determine the efficacy of sorafenib and of most antiangiogenic drugs in patients with HCC...
December 18, 2016: World Journal of Hepatology
https://www.readbyqxmd.com/read/28048234/su-f-i-19-mri-positive-contrast-visualization-of-prostate-brachytherapy-seeds-using-an-integrated-laplacian-based-phase-processing
#12
A Soliman, R Nosrati, H Safigholi, A Owrangi, G Morton, W Song
PURPOSE: To propose a new method that provides a positive contrast visualization of the prostate brachytherapy seeds using the phase information from MR images. Additionally, the feasibility of using the processed phase information to distinguish seeds from calcifications is explored. METHODS: A gel phantom was constructed using 2% agar dissolved in 1 L of distilled water. Contrast agents were added to adjust the relaxation times. Four iodine-125 (Eckert & Ziegler SML86999) dummy seeds were placed at different orientations with respect to the main magnetic field (B0)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047460/su-f-j-143-initial-assessment-of-image-quality-of-an-integrated-mr-linac-system-with-acr-phantom
#13
J Wang, J Yung, M Kadbi, Y Ding, C Fuller, G Ibbott
PURPOSE/OBJECTIVE(S): To assess the image quality of an integrated MR-Linac system and compare with other MRI systems that are primarily used for diagnostic purposes. MATERIALS/METHODS: An ACR MRI quality control (QC) phantom was used to evaluate the image quality of a fully integrated 1.5T MRI-Linac system recently installed at our institution. This system has a new split magnet design which gives the magnetic field strength of 1.5T. All images were acquired with a set of phased-array surface coils which are designed to have minimal attention of radiation beam...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046410/we-de-206-03-mri-image-formation-slice-selection-phase-encoding-frequency-encoding-k-space-snr
#14
C Lin
: Magnetic resonance imaging (MRI) has become an essential part of clinical imaging due to its ability to render high soft tissue contrast. Instead of ionizing radiation, MRI use strong magnetic field, radio frequency waves and field gradients to create diagnostic useful images. It can be used to image the anatomy and also functional and physiological activities within the human body. Knowledge of the basic physical principles underlying MRI acquisition is vitally important to successful image production and proper image interpretation...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046076/visual-imagery-and-false-memory-for-pictures-a-functional-magnetic-resonance-imaging-study-in-healthy-participants
#15
Christian Stephan-Otto, Sara Siddi, Carl Senior, Daniel Muñoz-Samons, Susana Ochoa, Ana María Sánchez-Laforga, Gildas Brébion
BACKGROUND: Visual mental imagery might be critical in the ability to discriminate imagined from perceived pictures. Our aim was to investigate the neural bases of this specific type of reality-monitoring process in individuals with high visual imagery abilities. METHODS: A reality-monitoring task was administered to twenty-six healthy participants using functional magnetic resonance imaging. During the encoding phase, 45 words designating common items, and 45 pictures of other common items, were presented in random order...
2017: PloS One
https://www.readbyqxmd.com/read/28029800/patellofemoral-kinematics-and-tibial-tuberosity-trochlear-groove-distances-in-female-adolescents-with-patellofemoral-pain
#16
Victor R Carlson, Barry P Boden, Frances T Sheehan
BACKGROUND: Patellofemoral pain (PFP) is a prevalent disorder among female adolescents. Overuse is frequently cited as the cause of pain for this population. What is currently unclear, however, is if the patella demonstrates abnormal tracking patterns relative to the femoral trochlear groove in female adolescents with PFP. PURPOSE: The aim of this case-control study was to determine if abnormal patellar tracking patterns are present in female adolescents with PFP...
December 1, 2016: American Journal of Sports Medicine
https://www.readbyqxmd.com/read/28019028/noninvasive-measurement-of-pressure-gradient-across-a-coronary-stenosis-using-phase-contrast-pc-mri-a-feasibility-study
#17
Zixin Deng, Zhaoyang Fan, Sang-Eun Lee, Christopher Nguyen, Yibin Xie, Jianing Pang, Xiaoming Bi, Qi Yang, Byoung-Wook Choi, Jung-Sun Kim, Daniel Berman, Hyuk-Jae Chang, Debiao Li
PURPOSE: To investigate the feasibility of blood pressure difference measurement, ΔP, across the coronary artery using phase contrast (PC)-MRI for potential noninvasive assessment of the functional significance of coronary artery stenosis. METHODS: Three-directional velocities in the coronary arteries acquired using 2D-PC-MRI were used with the Navier-Stokes equations to derive ΔP. Repeat phantom studies were performed to assess the reproducibility of flow velocity and ΔP...
December 26, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28011114/in-situ-investigation-of-ordering-phase-transformations-in-fept-magnetic-nanoparticles
#18
James E Wittig, James Bentley, Lawrence F Allard
In situ high-resolution electron microscopy was used to reveal information at the atomic level for the disordered-to-ordered phase transformation of equiatomic FePt nanoparticles that can exhibit outstanding magnetic properties after transforming from disordered face-centered-cubic into the tetragonal L10 ordered structure. High-angle annular dark-field imaging in the scanning transmission electron microscope provided sufficient contrast between the Fe and Pt atoms to readily monitor the ordering of the atoms during in situ heating experiments...
December 11, 2016: Ultramicroscopy
https://www.readbyqxmd.com/read/28009562/synchrotron-based-phase-sensitive-imaging-of%C3%A2-leaves-grown-from-magneto-primed-seeds-of-soybean
#19
A Fatima, S Kataria, L Baghel, K N Guruprasad, A K Agrawal, B Singh, P S Sarkar, T Shripathi, Y Kashyap
Experiments were conducted to study the effects of static magnetic fields (SMFs) on the venation network of soybean leaves using the synchrotron-based X-ray micro-imaging technique. The seeds of soybean (Glycine max, variety JS-335) were pretreated with different SMFs from 50 to 300 mT in steps of 50 mT for 1 h. The phase-contrast images obtained showed that, as the strength of the SMF increased, the area, width of the midrib, area of the midrib and minor vein of the middle leaflets of third trifoliate leaves also increased up to the SMF strength of 200 mT (1 h) and decreased thereafter...
January 1, 2017: Journal of Synchrotron Radiation
https://www.readbyqxmd.com/read/28005010/simultaneous-quantitative-imaging-of-electrical-properties-and-proton-density-from-b1-maps-using-mri
#20
Jiaen Liu, Pierre-Francois Van de Moortele, Xiaotong Zhang, Yicun Wang, Bin He
Electrical conductivity and permittivity of biological tissues are important diagnostic parameters and are useful for calculating subject-specific specific absorption rate distribution. On the other hand, water proton density also has clinical relevance for diagnosis purposes. These two kinds of tissue properties are inevitably associated in the technique of electrical properties tomography (EPT), which can be used to map in vivo electrical properties based on the measured B1 field distribution at Larmor frequency using magnetic resonance imaging (MRI)...
September 2016: IEEE Transactions on Medical Imaging
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