keyword
MENU ▼
Read by QxMD icon Read
search

MRI 7 Tesla

keyword
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
#1
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
#2
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
#3
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
https://www.readbyqxmd.com/read/27895684/investigation-of-the-gold-nanoparticles-effects-on-the-prostate-dose-distribution-in-brachytherapy-gel-dosimetry-and-monte-carlo-method
#4
Hossein Khosravi, Bijan Hashemi, Faezeh Rahmani, Ahmad Ebadi
PURPOSE: In this work, gold nanoparticles (GNPs) were embedded in the MAGIC-f polymer gel irradiated with the (192)Ir brachytherapy sources. MATERIAL AND METHODS: At the first plexiglas phantom was made as the human pelvis. The GNPs were synthesized with 15 nm in diameter and 0.1 mM (0.0197 mg/ml) in concentration by using a chemical reduction method. Then, the MAGIC-f gel was synthesized. The fabricated gel was poured into the tubes located at the prostate (with and without the GNPs) locations of the phantom...
October 2016: Journal of Contemporary Brachytherapy
https://www.readbyqxmd.com/read/27881126/initial-evaluation-of-prospective-cardiac-triggering-using-photoplethysmography-signals-recorded-with-a-video-camera-compared-to-pulse-oximetry-and-electrocardiography-at-7t-mri
#5
Nicolai Spicher, Markus Kukuk, Stefan Maderwald, Mark E Ladd
BACKGROUND: Accurate synchronization between magnetic resonance imaging data acquisition and a subject's cardiac activity ("triggering") is essential for reducing image artifacts but conventional, contact-based methods for this task are limited by several factors, including preparation time, patient inconvenience, and susceptibility to signal degradation. The purpose of this work is to evaluate the performance of a new contact-free triggering method developed with the aim to eventually replace conventional methods in non-cardiac imaging applications...
November 24, 2016: Biomedical Engineering Online
https://www.readbyqxmd.com/read/27872810/the-association-between-intra-and-juxta-cortical-pathology-and-cognitive-impairment-in-multiple-sclerosis-by-quantitative-t2-mapping-at-7%C3%A2-t-mri
#6
Céline Louapre, Sindhuja T Govindarajan, Costanza Giannì, Nancy Madigan, A Scott Nielsen, Jacob A Sloane, Revere P Kinkel, Caterina Mainero
Using quantitative T2* at 7 Tesla (T) magnetic resonance imaging, we investigated whether impairment in selective cognitive functions in multiple sclerosis (MS) can be explained by pathology in specific areas and/or layers of the cortex. Thirty-one MS patients underwent neuropsychological evaluation, acquisition of 7 T multi-echo T2* gradient-echo sequences, and 3 T anatomical images for cortical surfaces reconstruction. Seventeen age-matched healthy subjects served as controls. Cortical T2* maps were sampled at various depths throughout the cortex and juxtacortex...
2016: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27867929/comparison-of-3-and-7-tesla-magnetic-resonance-imaging-of-obstructive-hydrocephalus-caused-by-tectal-glioma
#7
Hyeong Cheol Moon, Hyeon-Man Baek, Young Seok Park
Obstructive hydrocephalus caused by tectal glioma, which relived by neuroendoscopy, have been described using 3.0 Tesla magnetic resonance imaging (3T MRI) so far, we present the results obtained from 3T and 7T MRI in this patient. A 21-year-old woman presented at our hospital with gait disturbance, hormonal insufficiency, and urinary incontinence that began prior to 6 years of age. 3.0T MRI revealed a non-enhancing tectal mass along with obstructive hydrocephalus. The mass measured approximately 1.1×1.0×1...
October 2016: Brain Tumor Research and Treatment
https://www.readbyqxmd.com/read/27865025/mr-targeted-imaging-for-the-expression-of-tenascin-c-in-myocardial-infarction-in-vivo
#8
Jiacheng Song, Jing Yu, Yan Li, Shanshan Lu, Zhanlong Ma, Haibin Shi
PURPOSE: To investigate the presence of viable myocardium in mice with acute myocardial infarction (MI) using a molecular targeted probe. MATERIALS AND METHODS: Super paramagnetic iron oxide (SPIO) nanoparticles and tenascin-C antibody were conjugated as an MRI probe. Fifteen mice with infarction were injected with SPIO-anti-tenascin-C (3 days [d], 5d, 7d after infarction; n = 5 for each group). Another five mice with infarction (5d, n = 5) were injected with SPIO for comparison...
November 16, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27862577/crossover-comparison-of-ferumoxytol-and-gadobenate-dimeglumine-for-abdominal-mr-angiography-at-3-0-tesla-effects-of-contrast-bolus-length-and-flip-angle
#9
Tilman Schubert, Utaroh Motosugi, Sonja Kinner, Timothy J Colgan, Samir D Sharma, Scott Hetzel, Shane Wells, Camilo A Campo, Scott B Reeder
PURPOSE: Ferumoxytol (FE) has gained interest as an alternative to gadolinium-based contrast agents (GBCAs). The purpose of this study was to evaluate and optimize ferumoxytol dose and T1 weighting, in comparison to a conventional GBCA. MATERIALS AND METHODS: Twelve healthy volunteers (six women / six men, mean age 44.3 years) were recruited for this study. Scanning was performed on a clinical 3 Tesla (T) MRI system. Gadobenate dimeglumine (GD)-enhanced MRA was performed followed by FE-enhanced MRA 1 month later...
November 10, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27861502/abnormal-profiles-of-local-functional-connectivity-proximal-to-focal-cortical-dysplasias
#10
René M H Besseling, Jacobus F A Jansen, Anton J A de Louw, Mariëlle C G Vlooswijk, M Christianne Hoeberigs, Albert P Aldenkamp, Walter H Backes, Paul A M Hofman
INTRODUCTION: Focal cortical dysplasia (FCD) is a congenital malformation of cortical development that often leads to medically refractory epilepsy. Focal resection can be an effective treatment, but is challenging as the surgically relevant abnormality may exceed the MR-visible lesion. The aim of the current study is to develop methodology to characterize the profile of functional connectivity around FCDs using resting-state functional MRI and in the individual patient. The detection of aberrant connectivity may provide a means to more completely delineate the clinically relevant lesion...
2016: PloS One
https://www.readbyqxmd.com/read/27859874/comparison-of-conventional-dce-mri-and-a-novel-golden-angle-radial-multicoil-compressed-sensing-method-for-the-evaluation-of-breast-lesion-conspicuity
#11
Laura Heacock, Yiming Gao, Samantha L Heller, Amy N Melsaether, James S Babb, Tobias K Block, Ricardo Otazo, Sungheon G Kim, Linda Moy
PURPOSE: To compare a novel multicoil compressed sensing technique with flexible temporal resolution, golden-angle radial sparse parallel (GRASP), to conventional fat-suppressed spoiled three-dimensional (3D) gradient-echo (volumetric interpolated breath-hold examination, VIBE) MRI in evaluating the conspicuity of benign and malignant breast lesions. MATERIALS AND METHODS: Between March and August 2015, 121 women (24-84 years; mean, 49.7 years) with 180 biopsy-proven benign and malignant lesions were imaged consecutively at 3...
November 17, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27859558/7-tesla-22-channel-wrap-around-coil-array-for-cervical-spinal-cord-and-brainstem-imaging
#12
Bei Zhang, Alan C Seifert, Joo-Won Kim, Joseph Borrello, Junqian Xu
PURPOSE: Increased signal-to-noise ratio and blood oxygenation level-dependent sensitivity at 7 Tesla (T) have the potential to enable high-resolution imaging of the human cervical spinal cord and brainstem. We propose a new two-panel radiofrequency coil design for these regions to fully exploit the advantages of ultra-high field. METHODS: A two-panel array, containing four transmit/receive and 18 receive-only elements fully encircling the head and neck, was constructed following simulations demonstrating the B1+ and specific absorption rate (SAR) benefits of two-panel over one-panel arrays...
November 17, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27856398/recovery-of-accurate-t2-from-historical-1-5-tesla-proton-density-and-t2-weighted-images-application-to-7-year-t2-changes-in-multiple-sclerosis-brain
#13
Md Nasir Uddin, Kelly C McPhee, Gregg Blevins, Alan H Wilman
OBJECTIVE: To determine accurate quantitative transverse relaxation times (T2) using retrospective clinical images and apply it to examine 7-year changes in multiple sclerosis (MS) brain. METHODS: A method for T2 mapping from retrospective proton density (PD) and T2-weighted fast spin echo images was recently introduced, but requires measurement of flip angles. We examined whether 1.5T flip angle variation in brain can be predicted, thus enabling T2 analysis of historical PD and T2-weighted images without a concurrent flip angle map...
November 14, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27851881/magnetic-resonance-safety-and-compatibility-of-tantalum-markers-used-in-proton-beam-therapy-for-intraocular-tumors-a-7-0-tesla-study
#14
Eva Oberacker, Katharina Paul, Till Huelnhagen, Celal Oezerdem, Lukas Winter, Andreas Pohlmann, Laura Boehmert, Oliver Stachs, Jens Heufelder, Andreas Weber, Matus Rehak, Ira Seibel, Thoralf Niendorf
PURPOSE: Proton radiation therapy (PRT) is a standard treatment of uveal melanoma. PRT patients undergo implantation of ocular tantalum markers (OTMs) for treatment planning. Ultra-high-field MRI is a promising technique for 3D tumor visualization and PRT planning. This work examines MR safety and compatibility of OTMs at 7.0 Tesla. METHODS: MR safety assessment included deflection angle measurements (DAMs), electromagnetic field (EMF) simulations for specific absorption rate (SAR) estimation, and temperature simulations for examining radiofrequency heating using a bow-tie dipole antenna for transmission...
November 10, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27851877/understanding-the-continuum-of-radionecrosis-and-vascular-disorders-in-the-brain-following-gamma-knife-irradiation-an-mri-study
#15
Julie Constanzo, Laurence Masson-Côté, Luc Tremblay, Jérémie P Fouquet, Philippe Sarret, Sameh Geha, Kevin Whittingstall, Benoit Paquette, Martin Lepage
PURPOSE: The radiation dose delivered to brain tumors is limited by the possibility to induce vascular damage and necrosis in surrounding healthy tissue. In the present study, we assessed the ability of MRI to monitor the cascade of events occurring in the healthy rat brain after stereotactic radiosurgery, which could be used to optimize the radiation treatment planning. METHODS: The primary somatosensory forelimb area (S1FL) and the primary motor cortex in the right hemisphere of Fischer rats (n = 6) were irradiated with a single dose of Gamma Knife radiation (Leksell Perfexion, Elekta AG, Stockholm, Sweden)...
November 10, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27843765/t2-relaxometry-predicts-outcome-of-dbs-in-idiopathic-parkinson-s-disease
#16
Tarja Lönnfors-Weitzel, Thilo Weitzel, Johannes Slotboom, Claus Kiefer, Claudio Pollo, Michael Schüpbach, Markus Oertel, Alain Kaelin, Roland Wiest
INTRODUCTION: Deep brain stimulation (DBS) nowadays is a well-established treatment of motor symptoms in Parkinson's disease. The subthalamic nucleus (STN) is a common target for DBS, because motor improvements have been shown to be superior to best medical therapy, if DBS electrodes have been appropriately positioned. DBS target identification can be assisted by MRI beyond structural imaging by spatially resolved measurement of T2-relaxation times (T2r). AIM: We pose the question, whether T2r of the STN is linked to the severity of the disease and whether outcome of DBS may be correlated to an asymmetric manifestation of the disease...
2016: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27806835/determinants-of-carotid-atherosclerotic-plaque-burden-in-a-stroke-free-population
#17
Mariana Selwaness, Reinhard Hameeteman, Ronald Van 't Klooster, Quirijn Van den Bouwhuijsen, Albert Hofman, Oscar H Franco, Wiro J Niessen, Stefan Klein, Meike W Vernooij, Aad Van der Lugt, Jolanda J Wentzel
BACKGROUND AND AIMS: In a large stroke-free population, we sought to identify cardiovascular risk factors and carotid plaque components associated with carotid plaque burden, lumen volume and stenosis. METHODS: The carotid arteries of 1562 stroke-free participants from The Rotterdam Study were imaged on a 1.5-Tesla MRI scanner. Inner and outer wall of the carotid arteries were automatically segmented and lumen volume (mm(3)), wall volume (outer wall-inner wall) and plaque burden (wall volume/outer wall volume) (%) were quantified...
October 14, 2016: Atherosclerosis
https://www.readbyqxmd.com/read/27806705/neuroimaging-in-vascular-cognitive-impairment-a-state-of-the-art-review
#18
REVIEW
Wolf-Dieter Heiss, Gary A Rosenberg, Alexander Thiel, Rok Berlot, Jacques de Reuck
Imaging is critical in the diagnosis and treatment of dementia, particularly in vascular cognitive impairment, due to the visualization of ischemic and hemorrhagic injury of gray and white matter. Magnetic resonance imaging (MRI) and positron emission tomography (PET) provide structural and functional information. Clinical MRI is both generally available and versatile - T2-weighted images show infarcts, FLAIR shows white matter changes and lacunar infarcts, and susceptibility-weighted images reveal microbleeds...
November 3, 2016: BMC Medicine
https://www.readbyqxmd.com/read/27797105/gradient-and-shim-pre-emphasis-by-inversion-of-a-linear-time-invariant-system-model
#19
S Johanna Vannesjo, Yolanda Duerst, Laetitia Vionnet, Benjamin E Dietrich, Matteo Pavan, Simon Gross, Christoph Barmet, Klaas P Pruessmann
PURPOSE: The goal of this contribution is to enhance the fidelity and switching speed of gradient and shim fields by advancing pre-emphasis toward broadband and full cross-term correction. THEORY AND METHODS: The proposed approach is based on viewing gradient and shim chains as linear, time-invariant (LTI) systems. Pre-emphasis is accomplished by inversion of a broadband digital system model. In the multiple-channel case, it amounts to a matrix of broadband filters that perform concerted self- and cross-term correction...
October 31, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27789649/persistent-idiopathic-facial-pain-a-prospective-systematic-study-of-clinical-characteristics-and-neuroanatomical-findings-at-3-0-tesla-mri
#20
Stine Maarbjerg, Frauke Wolfram, Tone Bruvik Heinskou, Per Rochat, Aydin Gozalov, Jannick Brennum, Jes Olesen, Lars Bendtsen
INTRODUCTION: Persistent idiopathic facial pain (PIFP) is a poorly understood chronic orofacial pain disorder and a differential diagnosis to trigeminal neuralgia. To address the lack of systematic studies in PIFP we here report clinical characteristics and neuroimaging findings in PIFP. METHODS: Data collection was prospective and standardized in consecutive PIFP patients. All patients underwent 3.0 MRI. RESULTS: In a cohort of 53 PIFP patients, the average age of onset was 44...
October 27, 2016: Cephalalgia: An International Journal of Headache
keyword
keyword
114726
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"