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https://www.readbyqxmd.com/read/28106942/assessment-of-intracranial-meningioma-associated-calcifications-using-susceptibility-weighted-mri
#1
Lisa C Adams, Sarah M Böker, Yvonne Y Bender, Eva M Fallenberg, Moritz Wagner, Ralph Buchert, Bernd Hamm, Marcus R Makowski
PURPOSE: To determine the diagnostic accuracy of susceptibility-weighted MRI (SW-MRI) for the detection of intracranial meningioma-associated calcifications compared with standard MR sequences, using computed tomography (CT) as a reference standard. MATERIALS AND METHODS: 354 patients, who had received both a CT and a 1.5 Tesla clinical brain MRI with SW-MRI sequences between January 2014 and July 2016, were retrospectively evaluated and 316 patients were included...
January 20, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28106936/whole-brain-vessel-wall-mri-a-parameter-tune-up-solution-to-improve-the-scan-efficiency-of-three-dimensional-variable-flip-angle-turbo-spin-echo
#2
Qi Yang, Zixin Deng, Xiaoming Bi, Shlee S Song, Konrad H Schlick, Nestor R Gonzalez, Debiao Li, Zhaoyang Fan
PURPOSE: To propose and evaluate a parameter tune-up solution to expedite a three-dimensional (3D) variable-flip-angle turbo spin-echo (TSE) sequence for whole-brain intracranial vessel wall (IVW) imaging. MATERIALS AND METHODS: Elliptical k-space sampling and prolonged echo train length (ETL), were used to expedite a 3D variable-flip-angle TSE-based sequence. To compensate for the potential loss in vessel wall signal, optimal combination of prescribed T2 and ETL was experimentally investigated on 22 healthy volunteers at 3 Tesla...
January 20, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28102957/rf-safety-assessment-of-a-bilateral-four-channel-transmit-receive-7-tesla-breast-coil-sar-versus-tissue-temperature-limits
#3
Thomas M Fiedler, Mark E Ladd, Andreas K Bitz
PURPOSE: The purpose of this work was to perform an RF safety evaluation for a bilateral four-channel transmit/receive breast coil and to determine the maximum permissible input power for which RF exposure of the subject stays within recommended limits. The safety evaluation was done based on SAR as well as on temperature simulations. In comparison to SAR, temperature is more directly correlated with tissue damage, which allows a more precise safety assessment. The temperature simulations were performed by applying three different blood perfusion models as well as two different ambient temperatures...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28090448/quantitative-techniques-for-musculoskeletal-mri-at-7-tesla
#4
REVIEW
Neal K Bangerter, Meredith D Taylor, Grayson J Tarbox, Antony J Palmer, Daniel J Park
Whole-body 7 Tesla MRI scanners have been approved solely for research since they appeared on the market over 10 years ago, but may soon be approved for selected clinical neurological and musculoskeletal applications in both the EU and the United States. There has been considerable research work on musculoskeletal applications at 7 Tesla over the past decade, including techniques for ultra-high resolution morphological imaging, 3D T2 and T2* mapping, ultra-short TE applications, diffusion tensor imaging of cartilage, and several techniques for assessing proteoglycan content in cartilage...
December 2016: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28073197/detection-rate-for-significant-cancer-at-confirmatory-biopsy-in-men-enrolled-in-active-surveillance-protocol-20-cores-vs-30-cores-vs-mri-trus-fusion-prostate-biopsy
#5
Pietro Pepe, Sebastiano Cimino, Antonio Garufi, Giandomenico Priolo, Giorgio Ivan Russo, Raimondo Giardina, Giulio Reale, Michele Barbera, Paolo Panella, Michele Pennisi, Giuseppe Morgia
INTRODUCTION: The detection rate for significant prostate cancer of extended vs saturation vs mMRI/TRUS fusion biopsy was prospectively evaluated in men enrolled in active surveillance (AS) protocol. Mterials and methods: From May 2013 to September 2016 75 men aged 66 years (median) with very low risk PCa were enrolled in an AS protocol and elegible criteria were: life expectancy greater than 10 years, cT1C, PSA below 10 ng/ml, PSA density < 0.20, 2 < unilateral positive biopsy cores, Gleason score (GS) equal to 6, greatest percentage of cancer (GPC) in a core < 50%...
December 30, 2016: Archivio Italiano di Urologia, Andrologia
https://www.readbyqxmd.com/read/28048810/su-f-i-25-reproducibility-of-phosphorus-mrs-and-work-measurements-for-evaluating-skeletal-muscle-metabolism
#6
F Settles, E Ripley, D Shengwen, G Clarke
PURPOSE: Skeletal muscle energetics were studied by phosphorus-31 MRS ((31) P-MRS) during exercise. The reproducibility of work performed and the MRS parameters were investigated. METHODS: Reproducibility of the (31) P-MRS exercise parameters was validated in five healthy volunteers (2 M/3 F, age 39.2 ± 21.9 yr, BMI 25.1 ± 4.8 kg/m(2) ). Five minute exercise of the vastus lateralis (VL) was performed on two separate occasions during MRS in a 3 Tesla MRI system...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046836/we-fg-202-08-assessment-of-treatment-response-via-longitudinal-diffusion-mri-on-a-mri-guided-system-initial-experience-of-quantitative-analysis
#7
X Qi, Y Yang, L Yang, D Low, K Sheng
PURPOSE: To report our initial experience of systematic monitoring treatment response using longitudinal diffusion MR images on a Co-60 MRI-guided radiotherapy system. METHODS: Four patients, including 2 head-and-necks, 1 sarcoma and 1 GBM treated on a 0.35 Tesla MRI-guided treatment system, were analyzed. For each patient, 3D TrueFISP MRIs were acquired during CT simulation and before each treatment for treatment planning and patient setup purposes respectively...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28019663/stereotactic-radiosurgery-planning-of-vestibular-schwannomas-is-mri-at-3-tesla-geometrically-accurate
#8
M A Schmidt, E J Wells, K Davison, A M Riddell, L Welsh, F Saran
PURPOSE: MRI is a mandatory requirement to accurately plan Stereotactic Radiosurgery (SRS) for Vestibular Schwannomas. However, MRI may be distorted due not only to inhomogeneity of the static magnetic field and gradients but also due to susceptibility-induced effects, which are more prominent at higher magnetic fields. We assess geometrical distortions around air spaces and consider MRI protocol requirements for SRS planning at 3T. METHODS: Hardware-related distortion and the effect of incorrect shimming were investigated with structured test objects...
December 26, 2016: Medical Physics
https://www.readbyqxmd.com/read/28008464/long-term-effects-of-the-collagenase-of-the-bacterium-clostridium-histolyticum-for-the-treatment-of-capsular-fibrosis-after-silicone-implants
#9
Sebastian Fischer, Yannick Diehm, Thomas Henzler, Martin R Berger, Jonas Kolbenschlag, Anne Latz, Ericka M Bueno, Christoph Hirche, Ulrich Kneser, Bohdan Pomahac
BACKGROUND: Capsular contracture remains the most frequent long-term complication after augmentation mammoplasty with silicone implants. Thereby, the main part of the fibrotic capsule is collagen. The collagenase of the bacterium Clostridium histolyticum is approved for the treatment of fibrotic diseases and has been demonstrated to be effective for capsular fibrosis treatment in the short term. However, long-term effectiveness is currently unknown but mandatory for clinical utilization...
December 23, 2016: Aesthetic Plastic Surgery
https://www.readbyqxmd.com/read/28005983/alterations-of-the-blood-brain-barrier-and-regional-perfusion-in-tumor-development-mri-insights-from-a-rat-c6-glioma-model
#10
Monika Huhndorf, Amir Moussavi, Nadine Kramann, Olga Will, Kirsten Hattermann, Christine Stadelmann, Olav Jansen, Susann Boretius
OBJECTIVES: Angiogenesis and anti-angiogenetic medications play an important role in progression and therapy of glioblastoma. In this context, in vivo characterization of the blood-brain-barrier and tumor vascularization may be important for individual prognosis and therapy optimization. METHODS: We analyzed perfusion and capillary permeability of C6-gliomas in rats at different stages of tumor-growth by contrast enhanced MRI and dynamic susceptibility contrast (DSC) MRI at 7 Tesla...
2016: PloS One
https://www.readbyqxmd.com/read/28000114/evaluation-of-a-laminin-alginate-biomaterial-adipocytes-and-adipocyte-derived-stem-cells-interaction-in-animal-autologous-fat-grafting-model-using-7-tesla-magnetic-resonance-imaging
#11
Yo-Shen Chen, Yu-Sheng Hsueh, Yen-Yu Chen, Cheng-Yu Lo, Hao-Chih Tai, Feng-Huei Lin
Biomaterials are often added to autologous fat grafts both as supporting matrices for the grafted adipocytes and as cell carrier for adipose-derived stem cells (ADSCs). This in vivo study used an autologous fat graft model to test a lamininalginate biomaterial, adipocytes, and ADSCs in immune-competent rats. We transplanted different combinations of shredded autologous adipose tissue [designated "A" for adipose tissue]), laminin-alginate beads [designated "B" for bead], and ADSCs [designated "C" for cell]) into the backs of 15 Sprague-Dawley rats...
January 2017: Journal of Materials Science. Materials in Medicine
https://www.readbyqxmd.com/read/27989341/juvenile-particulate-osteochondral-allograft-for-treatment-of-osteochondral-lesions-of-the-talus-detection-of-altered-repair-tissue-biochemical-composition-using-7-tesla-mri-and-t2-mapping
#12
Shaleen Vira, Austin J Ramme, Cary Chapman, Ding Xia, Ravinder R Regatte, Gregory Chang
During the previous 2 decades, numerous surgical procedures have become available to treat osteochondral lesions of the talus. The objective of the present study was to use 7 Tesla (7T) magnetic resonance imaging (MRI) to quantify and compare T2 values (a marker of collagen architecture) of native tibiotalar cartilage and cartilage repair tissue in patients treated with a juvenile particulate allograft for osteochondral lesions of the talus. The institutional review board approved the present study, and all subjects provided written informed consent...
January 2017: Journal of Foot and Ankle Surgery: Official Publication of the American College of Foot and Ankle Surgeons
https://www.readbyqxmd.com/read/27981667/assessment-of-pathological-complete-response-to-preoperative-chemoradiotherapy-by-means-of-multiple-mathematical-models-of-diffusion-weighted-mri-in-locally-advanced-rectal-cancer-a-prospective-single-center-study
#13
Hai-Bin Zhu, Xiao-Yan Zhang, Xiao-Hong Zhou, Xiao-Ting Li, Yu-Liang Liu, Shuai Wang, Ying-Shi Sun
PURPOSE: To assess stretched-exponential, mono-exponential and intravoxel incoherent motion (IVIM) models of diffusion-weighted MRI(DWI) in predicting pathological complete response (pCR) to neoadjuvant chemoradiotherapy (CRT) in rectal cancer patients. MATERIALS AND METHODS: This prospective study recruited 98 consecutive patients with locally advanced rectal cancer who underwent 3 Tesla MR examination before, during and after CRT. The apparent diffusion coefficient (ADC), IVIM-derived parameters (D, f, and D*), and stretched-exponential model-derived parameters (DDC and α) were measured...
December 16, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27981395/evaluation-of-exposure-to-ultra-high-static-magnetic-fields-during-activities-around-human-mri-scanners
#14
Mahsa Fatahi, Jolanta Karpowicz, Krzysztof Gryz, Amirmohammad Fattahi, Georg Rose, Oliver Speck
OBJECTIVE: To assess the individual exposure to the static magnetic field (SMF) and the motion-induced time-varying magnetic field (TVMF) generated by activities in an inhomogeneous SMF near high and ultra-high field magnetic resonance imaging (MRI) scanners. The study provides information on the level of exposure to high and ultra-high field MRI scanners during research activities. MATERIALS AND METHODS: A three-axis Hall magnetometer was used to determine the SMF and TVMF around human 3- and 7-Tesla (T) MRI systems...
December 16, 2016: Magma
https://www.readbyqxmd.com/read/27942477/the-effect-of-reducing-spatial-resolution-by-in-plane-partial-volume-averaging-on-peak-velocity-measurements-in-phase-contrast-magnetic-resonance-angiography
#15
Jonathan Rodrigues, Kishore Minhas, Guido Pieles, Elisa McAlindon, Christopher Occleshaw, Nathan Manghat, Mark Hamilton
BACKGROUND: The aim of this study was to quantify the degree of the effect of in-plane partial volume averaging on recorded peak velocity in phase contrast magnetic resonance angiography (PCMRA). METHODS: Using cardiac optimized 1.5 Tesla MRI scanners (Siemens Symphony and Avanto), 145 flow measurements (14 anatomical locations; ventricular outlets, aortic valve (AorV), aorta (5 sites), pulmonary arteries (3 sites), pulmonary veins, superior and inferior vena cava)- in 37 subjects (consisting of healthy volunteers, congenital and acquired heart disease patients) were analyzed by Siemens Argus default voxel averaging technique (where peak velocity = mean of highest velocity voxel and four neighbouring voxels) and by single voxel technique (1...
October 2016: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/27939623/factors-associated-with-meniscal-body-extrusion-on-knee-mri-in-overweight-and-obese-women
#16
F Zhang, S M Bierma-Zeinstra, E H G Oei, A Turkiewicz, M Englund, J Runhaar
OBJECTIVE: To determine factors associated with higher degree of meniscal body extrusion in overweight and obese women at high risk of knee osteoarthritis (OA). DESIGN: We used baseline data of the PRevention of knee Osteoarthritis in Overweight Females (PROOF) study, Netherlands, comprising overweight or obese women aged 50-60 years, free of clinical knee OA. All subjects completed a questionnaire on knee complaints and physical activity, underwent physical examination, radiography, and 1...
December 7, 2016: Osteoarthritis and Cartilage
https://www.readbyqxmd.com/read/27927229/evaluation-of-tumor-recurrences-after-radical-prostatectomy-using-18f-choline-pet-ct-and-3t-multiparametric-mri-without-endorectal-coil-a-single-center-experience
#17
Felipe Couñago, Manuel Recio, Antonio Maldonado, Elia Del Cerro, Ana Aurora Díaz-Gavela, Israel J Thuissard, David Sanz-Rosa, Francisco José Marcos, Karmele Olaciregui, María Mateo, Laura Cerezo
BACKGROUND: To evaluate and compare the utility of 18F-fluorocholine (18F-CH) PET/CT versus 3-Tesla multiparametric MRI (mpMRI) without endorectal coil to detect tumor recurrences in patients with biochemical relapse following radical prostatectomy (RP). Secondarily, to identify possible prognostic variables associated with mpMRI and 18F-CH PET/CT findings. METHODS: Retrospective study of 38 patients who developed biochemical recurrence after RP between the years 2011 and 2015 at our institution...
December 7, 2016: Cancer Imaging: the Official Publication of the International Cancer Imaging Society
https://www.readbyqxmd.com/read/27917112/reproducibility-and-reliability-of-quantitative-and-weighted-t1-and-t2-%C3%A2-mapping-for-myelin-based-cortical-parcellation-at-7-tesla
#18
Roy A M Haast, Dimo Ivanov, Elia Formisano, Kâmil Uludaǧ
Different magnetic resonance (MR) parameters, such as R1 (=1/T1) or T2(∗), have been used to visualize non-invasively the myelin distribution across the cortical sheet. Myelin contrast is consistently enhanced in the primary sensory and some higher order cortical areas (such as MT or the cingulate cortex), which renders it suitable for subject-specific anatomical cortical parcellation. However, no systematic comparison has been performed between the previously proposed MR parameters, i.e., the longitudinal and transversal relaxation values (or their ratios), for myelin mapping at 7 Tesla...
2016: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/27911950/a-specialized-multi-transmit-head-coil-for-high-resolution-fmri-of-the-human-visual-cortex-at-7t
#19
Shubharthi Sengupta, Alard Roebroeck, Valentin G Kemper, Benedikt A Poser, Jan Zimmermann, Rainer Goebel, Gregor Adriany
PURPOSE: To design, construct and validate radiofrequency (RF) transmit and receive phased array coils for high-resolution visual cortex imaging at 7 Tesla. METHODS: A 4 channel transmit and 16 channel receive array was constructed on a conformal polycarbonate former. Transmit field efficiency and homogeneity were simulated and validated, along with the Specific Absorption Rate, using [Formula: see text] mapping techniques and electromagnetic simulations. Receiver signal-to-noise ratio (SNR), temporal SNR (tSNR) across EPI time series, g-factors for accelerated imaging and noise correlations were evaluated and compared with a commercial 32 channel whole head coil...
2016: PloS One
https://www.readbyqxmd.com/read/27908188/polymer-gel-dosimetry-for-measuring-the-dose-near-thin-high-z-materials-irradiated-with-high-energy-photon-beams
#20
Leighton L Warmington, N Gopishankar, John H Broadhurst, Yoichi Watanabe
PURPOSE: To investigate the feasibility of three-dimensional (3D) dose measurements near thin high-Z materials placed in a water-like medium by using a polymer gel dosimeter (PGD) when the medium was irradiated with high energy photon beams. METHODS: PGD is potentially a useful tool for this application because it can record the dose around a small object made of a high-Z material in a continuous 3D medium. In this study, the authors manufactured a methacrylic acid-based normoxic PGD, nMAG...
December 2016: Medical Physics
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