keyword
MENU ▼
Read by QxMD icon Read
search

BOLD Mri

keyword
https://www.readbyqxmd.com/read/28634048/activation-volume-vs-bold-signal-change-as-measures-of-fmri-activation-its-impact-on-gaba-fmri-activation-correlation
#1
Pallab K Bhattacharyya, Micheal D Phillips, Lael A Stone, Mark J Lowe
PURPOSE: To explore the relative robustness of functional MRI (fMRI) activation volume and blood oxygen level-dependent (BOLD) signal change as fMRI metric, and to study the effect of relative robustness on the correlation between fMRI activation and cortical gamma amino butyric acid (GABA) in healthy controls and patients with multiple sclerosis (MS). METHODS: fMRI data were acquired from healthy controls and patients with MS, with the subjects peforming self paced bilateral finger tapping in block design...
June 17, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28629975/anatomical-and-functional-properties-of-the-foot-and-leg-representation-in-areas-3b-1-and-2-of-primary-somatosensory-cortex-in-humans-a-7t-fmri-study
#2
Michel Akselrod, Roberto Martuzzi, Andrea Serino, Wietske van der Zwaag, Roger Gassert, Olaf Blanke
Primary somatosensory cortex (S1) processes somatosensory information and is composed of multiple subregions. In particular, tactile information from the skin is encoded in three subregions, namely Brodmann areas (BAs) 3b, 1 and 2, with each area representing a complete map of the contralateral body. Although, much is known about the somatotopic organization of the hand in human S1, less research has been carried out regarding the somatotopic maps of the foot and leg in S1. Moreover, a latero-medial S1 organization along the superior part of the postcentral gyrus has been reported when moving from hip to toes, yet to date there is no study investigating leg/foot maps within the different subregions of S1...
June 16, 2017: NeuroImage
https://www.readbyqxmd.com/read/28628224/human-exposure-to-power-frequency-magnetic-fields-up-to-7-6%C3%A2-mt-an-integrated-eeg-fmri-study
#3
Julien Modolo, Alex W Thomas, Alexandre Legros
We assessed the effects of power-line frequency (60 Hz in North America) magnetic fields (MF) in humans using simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Twenty-five participants were enrolled in a pseudo-double-blind experiment involving "real" or "sham" exposure to sinusoidal 60 Hz MF exposures delivered using the gradient coil of an MRI scanner following two conditions: (i) 10 s exposures at 3 mT (10 repetitions); (ii) 2 s exposures at 7.6 mT (100 repetitions)...
June 19, 2017: Bioelectromagnetics
https://www.readbyqxmd.com/read/28623277/in-vivo-quantification-of-placental-insufficiency-by-bold-mri-a-human-study
#4
Jie Luo, Esra Abaci Turk, Carolina Bibbo, Borjan Gagoski, Drucilla J Roberts, Mark Vangel, Clare M Tempany-Afdhal, Carol Barnewolt, Judy Estroff, Arvind Palanisamy, William H Barth, Chloe Zera, Norberto Malpica, Polina Golland, Elfar Adalsteinsson, Julian N Robinson, Patricia Ellen Grant
Fetal health is critically dependent on placental function, especially placental transport of oxygen from mother to fetus. When fetal growth is compromised, placental insufficiency must be distinguished from modest genetic growth potential. If placental insufficiency is present, the physician must trade off the risk of prolonged fetal exposure to placental insufficiency against the risks of preterm delivery. Current ultrasound methods to evaluate the placenta are indirect and insensitive. We propose to use Blood-Oxygenation-Level-Dependent (BOLD) MRI with maternal hyperoxia to quantitatively assess mismatch in placental function in seven monozygotic twin pairs naturally matched for genetic growth potential...
June 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28588363/blood-oxygenation-level-dependent-functional-mri-of-early-evidences-of-brain-plasticity-after-hemodialysis-session-by-helixone-membrane-of-patients-with-indices-of-adrenal-deficiency
#5
Saïd Boujraf, Rachida Belaïch, Abdelkhalek Housni, Mustapha Maaroufi, Siham Tizniti, Tarik Sqalli, Mohammed Benzagmout
BACKGROUND: Various alterations of hypothalamic-pituitary-adrenal axis function have been described in patients with chronic renal failure. Nevertheless, controversial evidences were stated about the association between adrenal function deficiency (AD) and hemodialysis (HD). PURPOSE: The goal of this paper was to estimate indirect indices of the adrenal gland dysfunction which is potentially influenced by oxidative stress (OS) that still generates brain plasticity and reorganization of the functional control...
May 2017: Annals of Neurosciences
https://www.readbyqxmd.com/read/28582450/spontaneous-low-frequency-bold-signal-variations-from-resting-state-fmri-are-decreased-in-alzheimer-disease
#6
Samaneh Kazemifar, Kathryn Y Manning, Nagalingam Rajakumar, Francisco A Gómez, Andrea Soddu, Michael J Borrie, Ravi S Menon, Robert Bartha
Previous studies have demonstrated altered brain activity in Alzheimer's disease using task based functional MRI (fMRI), network based resting-state fMRI, and glucose metabolism from 18F fluorodeoxyglucose-PET (FDG-PET). Our goal was to define a novel indicator of neuronal activity based on a first-order textural feature of the resting state functional MRI (RS-fMRI) signal. Furthermore, we examined the association between this neuronal activity metric and glucose metabolism from 18F FDG-PET. We studied 15 normal elderly controls (NEC) and 15 probable Alzheimer disease (AD) subjects from the AD Neuroimaging Initiative...
2017: PloS One
https://www.readbyqxmd.com/read/28579187/functional-mri-bold-response-in-sickle-mice-with-hyperalgesia
#7
Ying Wang, Xiao Wang, Wei Chen, Kalpna Gupta, Xiao-Hong Zhu
Patients with sickle cell anemia (SCA) have abnormal hemoglobin (sickle hemoglobin S) leading to the crystallization of hemoglobin chains in red blood cells (RBCs), which assume sickle shape and display reduced flexibility. Sickle RBCs (sRBCs) adhere to vessel walls and block blood flow, thus preventing oxygen delivery to the tissues leading to vaso-occlusive crises (VOC), acute pain and organ damage. SCA patients often have chronic pain that can be attributed to inflammation, vasculopathy, neuropathy, ischemia-reperfusion injury and organ damage...
June 2017: Blood Cells, Molecules & Diseases
https://www.readbyqxmd.com/read/28578390/a-proof-of-concept-study-for-developing-integrated-two-photon-microscopic-and-magnetic-resonance-imaging-modality-at-ultrahigh-field-of-16-4-tesla
#8
Meng Cui, Yifeng Zhou, Bowen Wei, Xiao-Hong Zhu, Wei Zhu, Mark A Sanders, Kamil Ugurbil, Wei Chen
Functional magnetic resonance imaging (fMRI) based on the blood oxygen level dependent (BOLD) contrast has gained a prominent position in neuroscience for imaging neuronal activity and studying effective brain connectivity under working state and functional connectivity at resting state. However, the fundamental questions in regards to fMRI technology: how the BOLD signal inferences the underlying microscopic neuronal activity and physiological changes and what is the ultimate specificity of fMRI for functional mapping of microcircuits, remain unanswered...
June 2, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28572765/white-matter-structural-connectivity-is-not-correlated-to-cortical-resting-state-functional-connectivity-over-the-healthy-adult-lifespan
#9
Adrian Tsang, Catherine A Lebel, Signe L Bray, Bradley G Goodyear, Moiz Hafeez, Roberto C Sotero, Cheryl R McCreary, Richard Frayne
Structural connectivity (SC) of white matter (WM) and functional connectivity (FC) of cortical regions undergo changes in normal aging. As WM tracts form the underlying anatomical architecture that connects regions within resting state networks (RSNs), it is intuitive to expect that SC and FC changes with age are correlated. Studies that investigated the relationship between SC and FC in normal aging are rare, and have mainly compared between groups of elderly and younger subjects. The objectives of this work were to investigate linear SC and FC changes across the healthy adult lifespan, and to define relationships between SC and FC measures within seven whole-brain large scale RSNs...
2017: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/28560160/application-of-calibrated-fmri-in-alzheimer-s-disease
#10
Isabelle Lajoie, Scott Nugent, Clément Debacker, Kenneth Dyson, Felipe B Tancredi, AmanPreet Badhwar, Sylvie Belleville, Yan Deschaintre, Pierre Bellec, Julien Doyon, Christian Bocti, Serge Gauthier, Douglas Arnold, Marie-Jeanne Kergoat, Howard Chertkow, Oury Monchi, Richard D Hoge
Calibrated fMRI based on arterial spin-labeling (ASL) and blood oxygen-dependent contrast (BOLD), combined with periods of hypercapnia and hyperoxia, can provide information on cerebrovascular reactivity (CVR), resting blood flow (CBF), oxygen extraction fraction (OEF), and resting oxidative metabolism (CMRO2). Vascular and metabolic integrity are believed to be affected in Alzheimer's disease (AD), thus, the use of calibrated fMRI in AD may help understand the disease and monitor therapeutic responses in future clinical trials...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28559793/initial-validation-for-the-estimation-of-resting-state-fmri-effective-connectivity-by-a-generalization-of-the-correlation-approach
#11
Nan Xu, R Nathan Spreng, Peter C Doerschuk
Resting-state functional MRI (rs-fMRI) is widely used to noninvasively study human brain networks. Network functional connectivity is often estimated by calculating the timeseries correlation between blood-oxygen-level dependent (BOLD) signal from different regions of interest (ROIs). However, standard correlation cannot characterize the direction of information flow between regions. In this paper, we introduce and test a new concept, prediction correlation, to estimate effective connectivity in functional brain networks from rs-fMRI...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28550313/quantification-of-hepatocellular-carcinoma-heterogeneity-with-multiparametric-magnetic-resonance-imaging
#12
Stefanie J Hectors, Mathilde Wagner, Octavia Bane, Cecilia Besa, Sara Lewis, Romain Remark, Nelson Chen, M Isabel Fiel, Hongfa Zhu, Sacha Gnjatic, Miriam Merad, Yujin Hoshida, Bachir Taouli
Tumour heterogeneity poses a significant challenge for treatment stratification. The goals of this study were to quantify heterogeneity in hepatocellular carcinoma (HCC) using multiparametric magnetic resonance imaging (mpMRI), and to report preliminary data correlating quantitative MRI parameters with advanced histopathology and gene expression in a patient subset. Thirty-two HCC patients with 39 HCC lesions underwent mpMRI including diffusion-weighted imaging (DWI), blood-oxygenation-level-dependent (BOLD), tissue-oxygenation-level-dependent (TOLD) and dynamic contrast-enhanced (DCE)-MRI...
May 26, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28547846/multiline-balanced-ssfp-for-rapid-functional-imaging-at-ultrahigh-field
#13
Philipp Ehses, Klaus Scheffler
PURPOSE: The goal of this study is to develop and evaluate a multiline balanced steady-state free-precession (bSSFP) sequence for passband functional MRI at ultrahigh field. METHODS: Passband bSSFP functional MRI experiments using a visual task were performed on a 9.4 T system with echo trains ranging from one up to seven echoes. We analyze the acquisition efficiency, temporal and thermal signal-to-noise ratio, as well as the observed blood oxygen-level-dependent (BOLD) signal changes...
May 25, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28546311/evidence-for-functional-networks-within-the-human-brain-s-white-matter
#14
Michael Peer, Mor Nitzan, Atira S Bick, Netta Levin, Shahar Arzy
Investigation of the functional macro-scale organization of the human cortex is fundamental in modern neuroscience. While numerous studies have identified networks of interacting functional modules in the grey-matter, limited research was directed to the functional organization of the white-matter. Recent studies have demonstrated that the white-matter exhibits blood oxygen level dependent (BOLD) signal fluctuations similar to those of the grey-matter. Here we used these signal fluctuations to investigate whether the white-matter is organized as functional networks by applying a clustering analysis on resting-state functional MRI (RSfMRI) data from white-matter voxels, in 176 subjects (of both sexes)...
May 25, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28536517/differential-recruitment-of-parietal-cortex-during-spatial-and-non-spatial-reach-planning
#15
Pierre-Michel Bernier, Kevin Whittingstall, Scott T Grafton
The planning of goal-directed arm reaching movements is associated with activity in the dorsal parieto-frontal cortex, within which multiple regions subserve the integration of arm- and target-related sensory signals to encode a motor goal. Surprisingly, many of these regions show sustained activity during reach preparation even when target location is not specified, i.e., when a motor goal cannot be unambiguously formed. The functional role of these non-spatial preparatory signals remains unresolved. Here this process was investigated in humans by comparing reach preparatory activity in the presence or absence of information regarding upcoming target location...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28535912/effect-of-induced-high-myopia-on-functional-mri-signal-changes
#16
Ali Mirzajani, Mohammad Ghorbani, Behrouz Rasuli, Ali Mahmoud-Pashazadeh
PURPOSE: The current study evaluated the effect of lens-induced high myopia (IHM) on the activity of the occipital visual cortex during two visual stimuli presentations to the subjects. This was done by measuring the Blood Oxygenation Level Dependent (BOLD) signal using functional MRI (fMRI). METHODS: BOLD contrast fMRI was performed with a 1.5T MRI scanner on 12 emmetropic subjects (refractive error <±0.25Diopter) with no history of neurologic disorder. IHM conditions were applied to subjects by three convex lenses of +5D, +7D and +10D...
May 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28534652/a-review-of-the-evidence-of-zolpidem-efficacy-in-neurological-disability-after-brain-damage-due-to-stroke-trauma-and-hypoxia-a-justification-of-further-clinical-trials
#17
J A Sutton, R P Clauss
During 15 years, 23 clinical reports and 6 studies have demonstrated associations between sub-sedative doses of zolpidem and recoveries from brain damage due to strokes, trauma and hypoxia. Clinical findings include unexpected awakenings from vegetative states and regressions of stroke symptoms after dosing that disappear during elimination and reappear on repeat dosing. Initially single-photon emission computed tomography scans showed improved perfusion within, around and distant from infarctions. Then positron emission tomography scans and electroencephalography detected renewed metabolic and neuronal activity...
May 23, 2017: Brain Injury: [BI]
https://www.readbyqxmd.com/read/28528845/comparison-of-3t-and-7t-asl-techniques-for-concurrent-functional-perfusion-and-bold-studies
#18
Dimo Ivanov, Anna Gardumi, Roy A M Haast, Josef Pfeuffer, Benedikt A Poser, Kâmil Uludağ
Arterial spin labeling (ASL) is the primary non-invasive MRI approach to measure baseline cerebral blood flow (CBF) in healthy subjects and patients. ASL also allows concurrent functional BOLD signal and CBF measurements, but the latter typically suffer from low contrast-to-noise (CNR) ratio. Ultra-high-field imaging significantly boosts BOLD signal CNR. However, it is contested whether also CBF CNR benefits from increasing magnetic field strength, especially given that technical challenges related to field inhomogeneities and power deposition constraints exist...
May 19, 2017: NeuroImage
https://www.readbyqxmd.com/read/28506874/impact-of-acquisition-and-analysis-strategies-on-cortical-depth-dependent-fmri
#19
Sriranga Kashyap, Dimo Ivanov, Martin Havlicek, Benedikt A Poser, Kâmil Uludağ
Functional MRI at ultra-high magnetic fields (≥ 7T) provides the opportunity to probe columnar and laminar processing in the human brain in vivo at submillimeter spatial scales. However, fMRI data only indirectly reflects the neuronal laminar profile, due to a bias to ascending and pial veins inherent in gradient- and spin-echo BOLD fMRI. In addition, accurate delineation of the cortical depths is difficult, due to the relatively large voxel sizes and lack of sufficient tissue contrast in the functional images...
May 12, 2017: NeuroImage
https://www.readbyqxmd.com/read/28504360/oxygen-extraction-fraction-mapping-at-3-tesla-using-an-artificial-neural-network-a-feasibility-study
#20
Sebastian Domsch, Bettina Mürle, Sebastian Weingärtner, Jascha Zapp, Frederik Wenz, Lothar R Schad
PURPOSE: The oxygen extraction fraction (OEF) is an important biomarker for tissue-viability. MRI enables noninvasive estimation of the OEF based on the blood-oxygenation-level-dependent (BOLD) effect. Quantitative OEF-mapping is commonly applied using least-squares regression (LSR) to an analytical tissue model. However, the LSR method has not yet become clinically established due to the necessity for long acquisition times. Artificial neural networks (ANNs) recently have received increasing interest for robust curve-fitting and might pose an alternative to the conventional LSR method for reduced acquisition times...
May 14, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
keyword
keyword
114215
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"