keyword
MENU ▼
Read by QxMD icon Read
search

BOLD Mri

keyword
https://www.readbyqxmd.com/read/29454105/assessing-the-repeatability-of-absolute-cmro-2-oef-and-haemodynamic-measurements-from-calibrated-fmri
#1
Alberto Merola, Michael A Germuska, Kevin Murphy, Richard G Wise
As energy metabolism in the brain is largely oxidative, the measurement of cerebral metabolic rate of oxygen consumption (CMRO 2 ) is a desirable biomarker for quantifying brain activity and tissue viability. Currently, PET techniques based on oxygen isotopes are the gold standard for obtaining whole brain CMRO 2 maps. Among MRI techniques that have been developed as an alternative are dual calibrated fMRI (dcFMRI) methods, which exploit simultaneous measurements of BOLD and ASL signals during a hypercapnic-hyperoxic experiment to modulate brain blood flow and oxygenation...
February 14, 2018: NeuroImage
https://www.readbyqxmd.com/read/29447850/impact-of-baseline-co-2-on-blood-oxygenation-level-dependent-mri-measurements-of-cerebrovascular-reactivity-and-task-evoked-signal-activation
#2
Christiaan Hendrik Bas van Niftrik, Marco Piccirelli, Oliver Bozinov, Nicolai Maldaner, Catherine Strittmatter, Athina Pangalu, Antonios Valavanis, Luca Regli, Jorn Fierstra
Neurovascular coupling describes the cascade between neuronal activity and subsequent Blood-Oxygenation-Level-Dependent (BOLD) signal increase. Based on this premise, the correlation of this BOLD signal increase with a particular task, such as finger-tapping, is used to map neuronal activation. This signal increase may be dampened in brain areas exhibiting impaired cerebrovascular reactivity (BOLD-CVR), leading to false negative activation. Blood-oxygen-level-dependent (BOLD) cerebrovascular reactivity (CVR) has also been used to optimize task evoked BOLD signal changes...
February 12, 2018: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/29446322/bold-mri-to-evaluate-early-development-of-renal-injury-in-a-rat-model-of-diabetes
#3
Qidong Wang, Chuangen Guo, Lan Zhang, Rui Zhang, Zhaoming Wang, Ying Xu, Wenbo Xiao
Objective To investigate changes in renal oxygenation levels by blood-oxygenation-level dependent (BOLD)-magnetic resonance imaging (MRI), and to evaluate BOLD-MRI for detecting early diabetic renal injury. Methods Seventy-five rats, with unilateral nephrectomy, were randomly divided into streptozotocin-induced diabetes mellitus (DM, n = 65) and normal control (NC, n = 10) groups. BOLD-MRI scans were performed at baseline (both groups) and at 3, 7, 14, 21, 28, 35, 42, 49, 56, 63 and 70 days (DM only). Renal cortical (C) and medullary (M) R2* signals were measured and R2* medulla/cortex ratio (MCR) was calculated...
January 1, 2018: Journal of International Medical Research
https://www.readbyqxmd.com/read/29442388/maximizing-sensitivity-for-fast-gaba-edited-spectroscopy-in-the-visual-cortex-at-7%C3%A2-t
#4
Arjan D Hendriks, Alessio Fracasso, Catalina S Arteaga de Castro, Mark W J M Gosselink, Peter R Luijten, Natalia Petridou, Dennis W J Klomp
The combination of functional MRI (fMRI) and MRS is a promising approach to relate BOLD imaging to neuronal metabolism, especially at high field strength. However, typical scan times for GABA edited spectroscopy are of the order of 6-30 min, which is long compared with functional changes observed with fMRI. The aim of this study is to reduce scan time and increase GABA sensitivity for edited spectroscopy in the human visual cortex, by enlarging the volume of activated tissue in the primary visual cortex. A dedicated setup at 7 T for combined fMRI and GABA MRS is developed...
February 14, 2018: NMR in Biomedicine
https://www.readbyqxmd.com/read/29431005/reduced-blood-oxygenation-level-dependent-connectivity-is-related-to-hypoperfusion-in-alzheimer-s-disease
#5
Jens Göttler, Christine Preibisch, Isabelle Riederer, Lorenzo Pasquini, Panagiotis Alexopoulos, Karl Peter Bohn, Igor Yakushev, Ebba Beller, Stephan Kaczmarz, Claus Zimmer, Timo Grimmer, Alexander Drzezga, Christian Sorg
Functional connectivity of blood oxygenation level dependent signal fluctuations (BOLD-FC) is decreased in Alzheimer's disease (AD), and suggested to reflect reduced coherence in neural population activity; however, as both neuronal and vascular-hemodynamic processes underlie BOLD signals, impaired perfusion might also contribute to reduced BOLD-FC; 42 AD patients and 27 controls underwent simultaneous PET/MR imaging. Resting-state functional MRI assessed BOLD co-activity to quantify BOLD-FC, pulsed arterial spin labeling (pASL) assessed cerebral blood flow (CBF) as proxy for vascular hemodynamics, and 18F-fluorodeoxyglucose PET assessed glucose metabolism (GluMet) to index neuronal activity...
January 1, 2018: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/29426280/blood-oxygen-level-dependent-magnetic-resonance-imaging-for-detecting-pathological-patterns-in-lupus-nephritis-patients-a-preliminary-study-using-a-decision-tree-model
#6
Huilan Shi, Junya Jia, Dong Li, Li Wei, Wenya Shang, Zhenfeng Zheng
BACKGROUND: Precise renal histopathological diagnosis will guide therapy strategy in patients with lupus nephritis. Blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) has been applicable noninvasive technique in renal disease. This current study was performed to explore whether BOLD MRI could contribute to diagnose renal pathological pattern. METHODS: Adult patients with lupus nephritis renal pathological diagnosis were recruited for this study...
February 9, 2018: BMC Nephrology
https://www.readbyqxmd.com/read/29416525/patient-specific-alterations-in-co2-cerebrovascular-responsiveness-in-acute-and-sub-acute-sports-related-concussion
#7
W Alan C Mutch, Michael J Ellis, Lawrence N Ryner, Patrick J McDonald, Marc P Morissette, Philip Pries, Marco Essig, David J Mikulis, James Duffin, Joseph A Fisher
Background: Preliminary studies suggest that sports-related concussion (SRC) is associated with alterations in cerebral blood flow (CBF) regulation. Here, we use advanced magnetic resonance imaging (MRI) techniques to measure CBF and cerebrovascular responsiveness (CVR) in individual SRC patients and healthy control subjects. Methods: 15 SRC patients (mean age = 16.3, range 14-20 years) and 27 healthy control subjects (mean age = 17.6, range 13-21 years) underwent anatomical MRI, pseudo-continuous arterial spin labeling (pCASL) MRI and model-based prospective end-tidal targeting (MPET) of CO2 during blood oxygenation level-dependent (BOLD) MRI...
2018: Frontiers in Neurology
https://www.readbyqxmd.com/read/29410219/dopaminergic-modulation-of-hemodynamic-signal-variability-and-the-functional-connectome-during-cognitive-performance
#8
Mohsen Alavash, Sung-Joo Lim, Christiane Thiel, Bernhard Sehm, Lorenz Deserno, Jonas Obleser
Dopamine underlies important aspects of cognition, and has been suggested to boost cognitive performance. However, how dopamine modulates the large-scale cortical dynamics during cognitive performance has remained elusive. Using functional MRI during a working memory task in healthy young human listeners, we investigated the effect of levodopa (l-dopa) on two aspects of cortical dynamics, blood oxygen-level-dependent (BOLD) signal variability and the functional connectome of large-scale cortical networks. We here show that enhanced dopaminergic signaling modulates the two potentially interrelated aspects of large-scale cortical dynamics during cognitive performance, and the degree of these modulations is able to explain inter-individual differences in l-dopa-induced behavioral benefits...
February 2, 2018: NeuroImage
https://www.readbyqxmd.com/read/29408607/functional-mri-in-prenatally-opioid-exposed-children-during-a-working-memory-selective-attention-task
#9
Eivind Sirnes, Silja T Griffiths, Stein Magnus Aukland, Geir Egil Eide, Irene B Elgen, Hilde Gundersen
BACKGROUND: Opioid induced cerebral changes may contribute to neuropsychological difficulties, like attention problems, frequently reported in prenatally opioid-exposed children. Reduced regional brain volumes have been shown after prenatal opioid exposure, but no study to date has explored the possible impact of prenatal opioids on brain activation patterns. MATERIALS AND METHODS: A hospital-based sample of prenatally opioid-exposed school-aged children (n = 11) and unexposed controls (n = 12) underwent functional magnetic resonance imaging (fMRI) during a combined working memory-selective attention task...
February 1, 2018: Neurotoxicology and Teratology
https://www.readbyqxmd.com/read/29398359/ultra-slow-single-vessel-bold-and-cbv-based-fmri-spatiotemporal-dynamics-and-their-correlation-with-neuronal-intracellular-calcium-signals
#10
Yi He, Maosen Wang, Xuming Chen, Rolf Pohmann, Jonathan R Polimeni, Klaus Scheffler, Bruce R Rosen, David Kleinfeld, Xin Yu
Functional MRI has been used to map brain activity and functional connectivity based on the strength and temporal coherence of neurovascular-coupled hemodynamic signals. Here, single-vessel fMRI reveals vessel-specific correlation patterns in both rodents and humans. In anesthetized rats, fluctuations in the vessel-specific fMRI signal are correlated with the intracellular calcium signal measured in neighboring neurons. Further, the blood-oxygen-level-dependent (BOLD) signal from individual venules and the cerebral-blood-volume signal from individual arterioles show correlations at ultra-slow (<0...
January 26, 2018: Neuron
https://www.readbyqxmd.com/read/29389985/multiband-multi-echo-simultaneous-asl-bold-for-task-induced-functional-mri
#11
Alexander D Cohen, Andrew S Nencka, Yang Wang
Typical simultaneous blood oxygenation-level dependent (BOLD) and arterial spin labeling (ASL) sequences acquire two echoes, one perfusion-sensitive and one BOLD-sensitive. However, for ASL, spatial resolution and brain coverage are limited due to the T1 decay of the labeled blood. This study applies a sequence combining a multiband acquisition with four echoes for simultaneous BOLD and pseudo-continuous ASL (pCASL) echo planar imaging (MBME ASL/BOLD) for block-design task-fMRI. A multiband acceleration of four was employed to increase brain coverage and reduce slice-timing effects on the ASL signal...
2018: PloS One
https://www.readbyqxmd.com/read/29381374/obese-humans-have-disordered-brain-responses-to-food-images-during-physiological-hyperglycemia
#12
Renata Belfort-DeAguiar, Dongju Seo, Cheryl Lacadie, Sarita Naik, Christian Schmidt, Wai Lam, Janice Hwang, Todd Constable, Rajita Sinha, Robert S Sherwin
Blood glucose levels influence brain regulation of food intake. This study assessed the effect of mild physiological hyperglycemia on brain response to food cues in obese (OB) versus normal weight (NW) individuals. Brain responses in ten OB and ten NW non-diabetic healthy adults (BMI: 34{plus minus}3 vs. 23{plus minus}2 kg/m2, p<0.0001) were measured with functional MRI (BOLD contrast) in combination with a 2-step-normoglycemic-hyperglycemic-clamp. Participants were shown food and non-food (NF) images during normoglycemia (~95 mg/dL) and hyperglycemia (~130 mg/dL)...
January 30, 2018: American Journal of Physiology. Endocrinology and Metabolism
https://www.readbyqxmd.com/read/29359833/functional-connectivity-maps-based-on-hippocampal-and-thalamic-dynamics-may-account-for-the-default-mode-network
#13
Tien-Wen Lee, Shao-Wei Xue
The default-mode network (DMN) has been reported to comprise a set of inter-connected transmodal cortical areas, including the posterior cingulate cortex (PCC), medial prefrontal cortex, posterior inferior parietal lobule, lateral temporal region, and others. However, the subcortical constituents of the DMN are still not clear. This study aimed to examine whether the correlation maps derived from subcortical structures may also account for neural pattern of the DMN. Structural magnetic resonance imaging (MRI) and resting state functional MRI scans of 36 subjects were selected from the Rockland sample (Nathan Kline Institute)...
January 23, 2018: European Journal of Neuroscience
https://www.readbyqxmd.com/read/29352123/tumor-tissue-detection-using-blood-oxygen-level-dependent-functional-mri-based-on-independent-component-analysis
#14
Huiyuan Huang, Junfeng Lu, Jinsong Wu, Zhongxiang Ding, Shuda Chen, Lisha Duan, Jianling Cui, Fuyong Chen, Dezhi Kang, Le Qi, Wusi Qiu, Seong-Whan Lee, ShiJun Qiu, Dinggang Shen, Yu-Feng Zang, Han Zhang
Accurate delineation of gliomas from the surrounding normal brain areas helps maximize tumor resection and improves outcome. Blood-oxygen-level-dependent (BOLD) functional MRI (fMRI) has been routinely adopted for presurgical mapping of the surrounding functional areas. For completely utilizing such imaging data, here we show the feasibility of using presurgical fMRI for tumor delineation. In particular, we introduce a novel method dedicated to tumor detection based on independent component analysis (ICA) of resting-state fMRI (rs-fMRI) with automatic tumor component identification...
January 19, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29341006/mapping-functional-connectivity-in-the-rodent-brain-using-electric-stimulation-fmri
#15
Laura Pérez-Cervera, José María Caramés, Luis Miguel Fernández-Mollá, Andrea Moreno, Begoña Fernández, Elena Pérez-Montoyo, David Moratal, Santiago Canals, Jesús Pacheco-Torres
Since its discovery in the early 90s, BOLD signal-based functional Magnetic Resonance Imaging (fMRI) has become a fundamental technique for the study of brain activity in basic and clinical research. Functional MRI signals provide an indirect but robust and quantitative readout of brain activity through the tight coupling between cerebral blood flow and neuronal activation, the so-called neurovascular coupling. Combined with experimental techniques only available in animal models, such as intracerebral micro-stimulation, optogenetics or pharmacogenetics, provides a powerful framework to investigate the impact of specific circuit manipulations on overall brain dynamics...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29334834/mild-jugular-compression-collar-ameliorated-changes-in-brain-activation-of-working-memory-after-one-soccer-season-in-female-high-school-athletes
#16
Weihong Yuan, Jonathan Dudley, Kim Barber-Foss, Jonathan D Ellis, Staci Thomas, Ryan T Galloway, Christopher DiCesare, James Leach, Janet Adams, Thomas Maloney, Brooke Gadd, David Smith, Jeff Epstein, Dustin R Grooms, Kelsey Logan, David R Howell, Mekibib Altaye, Gregory D Myer
Recent neuroimaging studies have suggested that repetitive sub-concussive head impacts, even after only one sport season, may lead to pre- to post-season structural and functional alterations in male high school football athletes. However, data on female atheletes is limited. In the current investigation, we aimed to (1) assess the longitudinal pre- to post-season changes in fMRI of working memory and working memory performance, (2) quantify the association between the pre- to post-season change in fMRI of working memory and the exposure to head impact and working memory performance, and (3) assess whether wearing a neck collar designed to reduce intracranial slosh via mild compression of the jugular veins can ameliorate the changes in fMRI brain activation observed in the non-collar group after a full soccer season...
January 15, 2018: Journal of Neurotrauma
https://www.readbyqxmd.com/read/29331056/exploring-the-advantages-of-multiband-fmri-with-simultaneous-eeg-to-investigate-coupling-between-gamma-frequency-neural-activity-and-the-bold-response-in-humans
#17
Makoto Uji, Ross Wilson, Susan T Francis, Karen J Mullinger, Stephen D Mayhew
We established an optimal combination of EEG recording during sparse multiband (MB) fMRI that preserves high-resolution, whole-brain fMRI coverage while enabling broad-band EEG recordings which are uncorrupted by MRI gradient artefacts (GAs). We first determined the safety of simultaneous EEG recording during MB fMRI. Application of MB factor = 4 produced <1°C peak heating of electrode/hardware during 20 min of GE-EPI data acquisition. However, higher SAR sequences require specific safety testing, with greater heating observed using PCASL with MB factor = 4...
January 13, 2018: Human Brain Mapping
https://www.readbyqxmd.com/read/29325997/reduced-cortical-oxygenation-predicts-a-progressive-decline-of-renal-function-in-patients-with-chronic-kidney-disease
#18
Menno Pruijm, Bastien Milani, Edward Pivin, Agata Podhajska, Bruno Vogt, Matthias Stuber, Michel Burnier
Renal tissue hypoxia is a final pathway in the development and progression of chronic kidney disease (CKD), but whether renal oxygenation predicts renal function decline in humans has not been proven. Therefore, we performed a prospective study and measured renal tissue oxygenation by blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) in 112 patients with CKD, 47 with hypertension without CKD, and 24 healthy control individuals. Images were analyzed with the twelve-layer concentric objects method that divided the renal parenchyma in 12 layers of equal thickness and reports the mean R2* value of each layer (a high R2* corresponds to low oxygenation), along with the change in R2* between layers called the R2* slope...
January 9, 2018: Kidney International
https://www.readbyqxmd.com/read/29285809/investigation-of-the-bold-and-cbv-fmri-responses-to-somatosensory-stimulation-in-awake-marmosets-callithrix-jacchus
#19
Yoshiyuki Hirano, Cecil C Yen, Junjie V Liu, Julie B Mackel, Hellmut Merkle, George C Nascimento, Bojana Stefanovic, Afonso C Silva
Understanding the spatiotemporal features of the hemodynamic response function (HRF) to brain stimulation is essential for the correct application of neuroimaging methods to study brain function. Here, we investigated the spatiotemporal evolution of the blood oxygen level-dependent (BOLD) and cerebral blood volume (CBV) HRF in conscious, awake marmosets (Callithrix jacchus), a New World non-human primate with a lissencephalic brain and with growing use in biomedical research. The marmosets were acclimatized to head fixation and placed in a 7-T magnetic resonance imaging (MRI) scanner...
December 29, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/29285782/hyperpolarized-13-c-15-n2-urea-t2-relaxation-changes-in-acute-kidney-injury
#20
Christian Østergaard Mariager, Per Mose Nielsen, Haiyun Qi, Steffen Ringgaard, Christoffer Laustsen
PURPOSE: To investigate the correlation between renal ischemia and 13 C-urea T2 relaxation rate in an acute kidney injury (AKI) rat model. METHODS: Six rats subjected to unilateral renal ischemia were investigated. Creatinine clearance, urine output, plasma creatinine as well as blood-urea nitrogen (BUN) values were acquired before and after the procedure. 1 H T2* mapping was acquired using blood oxygenation level dependent (BOLD) MRI and hyperpolarized 13 C-urea T2 mapping was acquired using a 2D golden-angle radial approach...
December 28, 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"