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Functional MRI

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https://www.readbyqxmd.com/read/27913820/cerebral-blood-flow-transit-time-and-apparent-diffusion-coefficient-in-moyamoya-disease-before-and-after-acetazolamide
#1
Christian Federau, Soren Christensen, Zungho Zun, Sun-Won Park, Wendy Ni, Michael Moseley, Greg Zaharchuk
INTRODUCTION: The goal of this study was to assess the changes in arterial spin labeling (ASL) cerebral blood flow (CBF) and arterial transit time (ATT), and in apparent diffusion coefficient (ADC), before and after an acetazolamide challenge in moyamoya patients, as function of arterial stenosis severity. METHODS: Pre-operative patients diagnosed with moyamoya disease who could undergo MRI at 3.0T were recruited for this study. A multi-delay pseudo-continuous ASL and a diffusion-weighted sequence were acquired before and 15 min after acetazolamide injection...
December 2, 2016: Neuroradiology
https://www.readbyqxmd.com/read/27913627/aberrant-interhemispheric-homotopic-functional-and-structural-connectivity-in-amyotrophic-lateral-sclerosis
#2
Jiuquan Zhang, Bing Ji, Jun Hu, Chaoyang Zhou, Longchuan Li, Zhihao Li, Xuequan Huang, Xiaoping Hu
OBJECTIVE: Amyotrophic lateral sclerosis (ALS) is an idiopathic and fatal neurodegenerative disease of the human motor system. While microstructural alterations in corpus callosum (CC) have been identified as a consistent feature of ALS, studies directly examining interhemispheric neural connectivity are still lacking. To shed more light on the pathophysiology of ALS, the present study aims to examine alterations of interhemispheric structural and functional connectivity in individuals with ALS...
December 2, 2016: Journal of Neurology, Neurosurgery, and Psychiatry
https://www.readbyqxmd.com/read/27913338/intracardiac-vortex-dynamics-by-high-frame-rate-doppler-vortography-i-in-vivo-i-comparison-with-vector-flow-mapping-and-4-d-flow-mri
#3
Julia Faurie, Mathilde Baudet, Kondo Claude Assi, Dominique Auger, Guillaume Gilbert, Francois Tournoux, Damien Garcia
Recent studies have suggested that intracardiac vortex flow imaging could be of clinical interest to early diagnose the diastolic heart function. Doppler vortography has been intro-duced as a simple color Doppler method to detect and quantify intraventricular vortices. This method is able to locate a vortex core based on the recognition of an antisymmetric pattern in the Doppler velocity field. Because the heart is a fast-moving organ, high frame rates are needed to decipher the whole blood vortex dynamics during diastole...
November 29, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27913180/structure-activity-and-in-vivo-evaluation-of-a-novel-lipoprotein-lipase-lpl-activator
#4
Werner J Geldenhuys, Joel Caporoso, Thomas C Leeper, Yoon-Kwang Lee, Li Lin, Altaf S Darvesh, Prabodh Sadana
Elevated triglycerides (TG) contribute towards increased risk for cardiovascular disease. Lipoprotein lipase (LPL) is an enzyme that is responsible for the metabolism of core triglycerides of very-low density lipoproteins (VLDL) and chylomicrons in the vasculature. In this study, we explored the structure-activity relationships of our lead compound (C10d) that we have previously identified as an LPL agonist. We found that the cyclopropyl moiety of C10d is not absolutely necessary for LPL activity. Several substitutions were found to result in loss of LPL activity...
November 21, 2016: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/27911950/a-specialized-multi-transmit-head-coil-for-high-resolution-fmri-of-the-human-visual-cortex-at-7t
#5
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/27911758/multimodal-imaging-for-dreadd-expressing-neurons-in-living-brain-and-their-application-to-implantation-of-ipsc-derived-neural-progenitors
#6
Bin Ji, Hiroyuki Kaneko, Takafumi Minamimoto, Haruhisa Inoue, Hiroki Takeuchi, Katsushi Kumata, Ming-Rong Zhang, Ichio Aoki, Chie Seki, Maiko Ono, Masaki Tokunaga, Satoshi Tsukamoto, Koji Tanabe, Ryong-Moon Shin, Takeharu Minamihisamatsu, Seiji Kito, Barry J Richmond, Tetsuya Suhara, Makoto Higuchi
: Chemogenetic manipulation of neuronal activities has been enabled by a designer receptor (designer receptor exclusively activated by designer drugs, DREADD) that is activated exclusively by clozapine-N-oxide (CNO). Here, we applied CNO as a functional reporter probe to positron emission tomography (PET) of DREADD in living brains. Mutant human M4 DREADD (hM4Di) expressed in transgenic (Tg) mouse neurons was visualized by PET with microdose [(11)C]CNO. Deactivation of DREADD-expressing neurons in these mice by nonradioactive CNO at a pharmacological dose could also be captured by arterial spin labeling MRI (ASL-MRI)...
November 9, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27911456/mid-term-results-of-recap-magnum-taperloc-metal-on-metal-total-hip-arthroplasty-with-mean-follow-up-of-7-1-years
#7
Antonios A Koutalos, Aristotelis Kourtis, Ian C Clarke, Evert J Smith
INTRODUCTION: Despite enthusiasm for metal-on-metal bearings, disappointing short- to mid-term outcomes has all but halted the use of this bearing articulation. This review presents mid-term results for the ReCap Magnum total hip replacement. PATIENTS AND METHODS: This prospective study evaluated 79 ReCap/Magnum/Taperloc total hip replacements with mean follow-up of 7.1 (range 3.7-9.2) years. 43 were female and 36 male. Metal ions were measured and radiographic measurement included a 'margin of safety' angle to quantify risk of edge loading...
December 2, 2016: Hip International: the Journal of Clinical and Experimental Research on Hip Pathology and Therapy
https://www.readbyqxmd.com/read/27911366/a-multimodal-imaging-and-stimulation-based-method-of-evaluating-connectivity-related-brain-excitability-in-patients-with-epilepsy
#8
Mouhsin M Shafi, Susan Whitfield-Gabrieli, Catherine J Chu, Alvaro Pascual-Leone, Bernard S Chang
Resting-state functional connectivity MRI (rs-fcMRI) is a technique that identifies connectivity between different brain regions based on correlations over time in the blood-oxygenation level dependent signal. rs-fcMRI has been applied extensively to identify abnormalities in brain connectivity in different neurologic and psychiatric diseases. However, the relationship among rs-fcMRI connectivity abnormalities, brain electrophysiology and disease state is unknown, in part because the causal significance of alterations in functional connectivity in disease pathophysiology has not been established...
November 13, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/27911321/the-effects-of-meditation-on-grey-matter-atrophy-and-neurodegeneration-a%C3%A2-systematic-review
#9
Nicole Last, Emily Tufts, Leslie E Auger
The present systematic review is based on the premise that a variety of neurodegenerative diseases are accompanied by grey matter atrophy in the brain and meditation may impact this. Given that age is a major risk factor for many of these progressive and neurodegenerative diseases and that the percentage of the population over the age of 65 is quickly increasing, there is an obvious need for prompt treatment and prevention advances in research. As there is currently no cure for Alzheimer's disease and other neurodegenerative diseases, many are seeking non-pharmacological treatment options in attempts to offset the disease-related cognitive and functional declines...
November 26, 2016: Journal of Parkinson's Disease
https://www.readbyqxmd.com/read/27911319/autotaxin-is-related-to-metabolic-dysfunction-and-predicts-alzheimer-s-disease-outcomes
#10
Kelsey E McLimans, Auriel A Willette
BACKGROUND: Obesity and insulin resistance are associated with neuropathology and cognitive decline in Alzheimer's disease (AD). OBJECTIVE: Ecto-nucleotide pyrophosphatase/phosphodiesterase 2, also called autotaxin, is produced by beige adipose tissue, regulates metabolism, and is higher in AD prefrontal cortex (PFC). Autotaxin may be a novel biomarker of dysmetabolism and AD. METHODS: We studied Alzheimer's Disease Neuroimaging Initiative participants who were cognitively normal (CN; n = 86) or had mild cognitive impairment (MCI; n = 135) or AD (n = 66)...
December 1, 2016: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/27911308/the-effects-of-gene-mutations-on%C3%A2-default%C3%A2-mode-network-in%C3%A2-familial%C3%A2-alzheimer-s-disease
#11
Xiaozhen Li, Eric Westman, Steinunn Thordardottir, Anne Kinhult Ståhlbom, Ove Almkvist, Kaj Blennow, Lars-Olof Wahlund, Caroline Graff
Familial Alzheimer's disease (FAD) mutations have very high penetrance but age at onset and rate of disease progression differ. Neuroimaging and cerebrospinal fluid (CSF) examinations in mutation carriers (MCs) may provide an opportunity to identify early biomarkers that can be used to track disease progression from presymptomatic to the dementia stages of disease. The default mode network (DMN) is a resting state neuronal network composed of regions known to associate with amyloid deposition in AD. We hypothesized that functional connectivity in the DMN might change at pre-clinical stages in FAD MCs and correlate with changes in CSF biomarkers as a consequence of AD brain pathology...
November 29, 2016: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/27910866/biomechanical-analysis-of-normal-brain-development-during-the-first-year-of-life-using-finite-strain-theory
#12
Jeong Chul Kim, Li Wang, Dinggang Shen, Weili Lin
The first year of life is the most critical time period for structural and functional development of the human brain. Combining longitudinal MR imaging and finite strain theory, this study aimed to provide new insights into normal brain development through a biomechanical framework. Thirty-three normal infants were longitudinally imaged using MRI from 2 weeks to 1 year of age. Voxel-wise Jacobian determinant was estimated to elucidate volumetric changes while Lagrange strains (both normal and shear strains) were measured to reveal directional growth information every 3 months during the first year of life...
December 2, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27909774/evaluation-of-upper-abdominal-organs-with-dwi-in-patients-with-familial-mediterranean-fever
#13
Eda Albayrak, Safak Sahin
PURPOSE: To investigate the diagnostic efficiency of diffusion-weighted magnetic resonance imaging (DWI) for the evaluation of functional changes that can occur in upper abdominal organs in patients with familial Mediterranean fever (FMF). METHODS: The study included 50 controls, 45 patients with FMF, and 14 patients with FMF who had accompanying proteinuria. Measurement of apparent diffusion coefficient (ADC) was performed using DWI sections obtained from liver, spleen, kidney, and pancreas parenchyma with 1...
December 2, 2016: Abdominal Radiology
https://www.readbyqxmd.com/read/27909401/implicit-learning-in-transient-global-amnesia-and-the-role-of-stress
#14
Frauke Nees, Martin Griebe, Anne Ebert, Michaela Ruttorf, Benjamin Gerber, Oliver T Wolf, Lothar R Schad, Achim Gass, Kristina Szabo
Transient global amnesia (TGA) is a disorder with reversible anterograde disturbance of explicit memory, frequently preceded by an emotionally or physically stressful event. By using magnetic resonance imaging (MRI) following an episode of TGA, small hippocampal lesions have been observed. Hence it has been postulated that the disorder is caused by the stress-related transient inhibition of memory formation in the hippocampus. In experimental studies, stress has been shown to affect both explicit and implicit learning-the latter defined as learning and memory processes that lack conscious awareness of the information acquired...
2016: Frontiers in Behavioral Neuroscience
https://www.readbyqxmd.com/read/27909095/dynamic-shifts-in-large-scale-brain-network-balance-as-a-function-of-arousal
#15
Christina B Young, Gal Raz, Daphne Everaerd, Christian F Beckmann, Indira Tendolkar, Talma Hendler, Guillén Fernández, Erno J Hermans
: The ability to temporarily prioritize rapid and vigilant reactions over slower higher-order cognitive functions is essential for adaptive responding to threat. This reprioritization is believed to reflect shifts in resource allocation between large-scale brain networks that support these cognitive functions, including the salience and executive control networks. How changes in communication within and between such networks dynamically unfold as a function of threat-related arousal, however, remains unknown...
December 1, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27908914/muscle-mania-the-quest-for-the-perfect-body
#16
Maira Hameed, Ajay Sahu, Maria B Johnson
We describe the case of a young man with repeated hospital presentations for a variety of symptoms related to excessive bodybuilding and associated behaviours. He presented to our department (radiology) with right arm pain and loss of function. Ultrasound showed complete triceps rupture, rare in young patients and multiple cystic areas within the muscles of the arm. MRI revealed these to be multiple proteinaceous lesions within the muscle bellies and the possibility of self-innoculation was raised by the reporting radiologist...
December 1, 2016: BMJ Case Reports
https://www.readbyqxmd.com/read/27908187/dosimetric-characterization-of-mri-only-treatment-planning-for-brain-tumors-in-atlas-based-pseudo-ct-images-generated-from-standard-t1-weighted-mr-images
#17
Benjamin Demol, Christine Boydev, Juha Korhonen, Nick Reynaert
PURPOSE: Magnetic resonance imaging (MRI)-only radiotherapy treatment planning requires accurate pseudo-CT (pCT) images for precise dose calculation. The current work introduced an atlas-based method combined with MR intensity information. pCT analyses and Monte Carlo dose calculations for intracranial stereotactic treatments were performed. METHODS: Twenty-two patients, representing 35 tumor targets, were scanned using a 3D T1-weighted MRI sequence according to the clinical protocol...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27908178/a-probability-based-multi-cycle-sorting-method-for-4d-mri-a-simulation-study
#18
Xiao Liang, Fang-Fang Yin, Yilin Liu, Jing Cai
PURPOSE: To develop a novel probability-based sorting method capable of generating multiple breathing cycles of 4D-MRI images and to evaluate performance of this new method by comparing with conventional phase-based methods in terms of image quality and tumor motion measurement. METHODS: Based on previous findings that breathing motion probability density function (PDF) of a single breathing cycle is dramatically different from true stabilized PDF that resulted from many breathing cycles, it is expected that a probability-based sorting method capable of generating multiple breathing cycles of 4D images may capture breathing variation information missing from conventional single-cycle sorting methods...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27908177/automatic-segmentation-of-right-ventricle-in-cardiac-cine-mr-images-using-a-saliency-analysis
#19
Angélica Atehortúa, Maria A Zuluaga, Juan D García, Eduardo Romero
PURPOSE: Accurate measurement of the right ventricle (RV) volume is important for the assessment of the ventricular function and a biomarker of the progression of any cardiovascular disease. However, the high RV variability makes difficult a proper delineation of the myocardium wall. This paper introduces a new automatic method for segmenting the RV volume from short axis cardiac magnetic resonance (MR) images by a salient analysis of temporal and spatial observations. METHODS: The RV volume estimation starts by localizing the heart as the region with the most coherent motion during the cardiac cycle...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27908173/pacemaker-and-icd-oversensing-induced-by-movements-near-the-mri-scanner-bore
#20
E Mattei, F Censi, G Calcagnini, R Falsaperla, E Genovese, A Napolitano, V Cannatà
PURPOSE: The effect of the movement near the MRI scanner bore for people with a pacemaker (PM) or an implantable cardioverter defibrillator (ICD) is experimentally evaluated and discussed. METHODS: The authors performed in vitro measurements on a saline-filled human-shaped phantom (male, 170 cm height), equipped first with an MR-conditional PM (bicameral configuration, DDD programming), then with an MR-conditional ICD (biventricular configuration, detection algorithms enable but shock delivery disable)...
December 2016: Medical Physics
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