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Cerebrovascular reactivity, CVR,

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https://www.readbyqxmd.com/read/28152241/invalidation-of-fmri-experiments-secondary-to-neurovascular-uncoupling-in-patients-with-cerebrovascular-disease
#1
Andrea E Para, Kevin Sam, Julien Poublanc, Joseph A Fisher, Adrian P Crawley, David J Mikulis
PURPOSE: Blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is a technique used to infer neuronal activity from the observed changes in blood flow. Cerebrovascular reactivity (CVR) is the ability of arterioles to increase blood flow in response to vasodilatory stimulus. We hypothesize that in areas of disease where there is exhausted vascular reserve and impaired CVR there will be diminished blood flow response following neuronal activation, and that these areas would appear as false-negative tests on BOLD fMRI...
February 2, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28061015/impact-of-vessel-wall-lesions-and-vascular-stenoses-on-cerebrovascular-reactivity-in-patients-with-intracranial-stenotic-disease
#2
Petrice M Cogswell, Taylor L Davis, Megan K Strother, Carlos C Faraco, Allison O Scott, Lori C Jordan, Matthew R Fusco, Blaise deB Frederick, Jeroen Hendrikse, Manus J Donahue
PURPOSE: To compare cerebrovascular reactivity (CVR) and CVR lagtimes in flow territories perfused by vessels with vs. without proximal arterial wall disease and/or stenosis, separately in patients with atherosclerotic and nonatherosclerotic (moyamoya) intracranial stenosis. MATERIALS AND METHODS: Atherosclerotic and moyamoya patients with >50% intracranial stenosis and <70% cervical stenosis underwent angiography, vessel wall imaging (VWI), and CVR-weighted imaging (n = 36; vessel segments evaluated = 396)...
January 6, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28047432/su-g-iep1-11-resting-state-fluctuation-of-bold-signal-amplitude-for-mapping-cerebrovascular-reactivity-in-presurgical-functional-mri
#3
P Wang, P Hou, S Kesler, R Colen, A Kumar, S Prabhu, H Liu
PURPOSE: Cerebrovascular reactivity (CVR) MRI with hypercapnia challenges, such as a breath-hold (BH) task, has been proposed to indicate areas with neurovascular uncoupling potentials for presurgical functional MRI (fMRI). This study aimed to explore the use of resting-state (RS) fMRI, in particular, the RS fluctuation of amplitude (RSFA) for detecting the impaired CVR and compare with BH MRI in patients with gliomas. METHODS: The BH and RS fMRI from six patients as part of their presurgical fMRI studies were analyzed...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28029271/hemodynamic-mechanisms-underlying-elevated-oxygen-extraction-fraction-oef-in-moyamoya-and-sickle-cell-anemia-patients
#4
Jennifer M Watchmaker, Meher R Juttukonda, Larry T Davis, Allison O Scott, Carlos C Faraco, Melissa C Gindville, Lori C Jordan, Petrice M Cogswell, Angela L Jefferson, Howard S Kirshner, Manus J Donahue
Moyamoya is a bilateral, complex cerebrovascular condition characterized by progressive non-atherosclerotic intracranial stenosis and collateral vessel formation. Moyamoya treatment focuses on restoring cerebral blood flow (CBF) through surgical revascularization, however stratifying patients for revascularization requires abilities to quantify how well parenchyma is compensating for arterial steno-occlusion. Globally elevated oxygen extraction fraction (OEF) secondary to CBF reduction may serve as a biomarker for tissue health in moyamoya patients, as suggested in patients with sickle cell anemia (SCA) and reduced oxygen carrying capacity...
January 1, 2016: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/27978784/correlation-between-decreased-parasympathetic-activity-and-reduced-cerebrovascular-reactivity-in-patients-with-lacunar-infarct
#5
Kannakorn Intharakham, Kesorn Suwanprasert, Sombat Muengtaweepongsa
Reduced cerebrovascular reactivity (CVR) was found in patients with recent lacunar infarct. However, its mechanisms were controversial. The breath holding maneuver as vasodilatory stimulus is clinically useful for an estimation of cerebrovasomotor reactivity in well co-operative patients. Patients with lacunar infarct have no higher cortical dysfunction and remain well co-operation. The breath holding maneuver is feasible and safe to perform in patients with lacunar infarct. Autonomic nervous system regulates systemic vascular activity...
13, 2016: Current Neurovascular Research
https://www.readbyqxmd.com/read/27942454/acetazolamide-augmented-dynamic-bold-aczbold-imaging-for-assessing-cerebrovascular-reactivity-in-chronic-steno-occlusive-disease-of-the-anterior-circulation-an-initial-experience
#6
Junjie Wu, Seena Dehkharghani, Fadi Nahab, Deqiang Qiu
The purpose of this study was to measure cerebrovascular reactivity (CVR) in chronic steno-occlusive disease using a novel approach that couples BOLD imaging with acetazolamide (ACZ) vasoreactivity (aczBOLD), to evaluate dynamic effects of ACZ on BOLD and to establish the relationship between aczBOLD and dynamic susceptibility contrast (DSC) perfusion MRI. Eighteen patients with unilateral chronic steno-occlusive disease of the anterior circulation underwent a 20-min aczBOLD imaging protocol, with ACZ infusion starting at 5 min of scan initiation...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27939758/assessment-of-hemodynamic-compromise-using-computed-tomography-perfusion-in-combination-with-123-i-imp-single-photon-emission-computed-tomography-without-acetazolamide-challenge-test
#7
Atsumu Hashimoto, Takeshi Mikami, Katsuya Komatsu, Shouhei Noshiro, Tohru Hirano, Masahiko Wanibuchi, Nobuhiro Mikuni
OBJECTIVES: The acetazolamide challenge test in conjunction with (123)I-IMP single-photon emission computed tomography (SPECT) is a known method of assessing cerebrovascular reserve capacity. In this study, we investigated whether CT perfusion in combination with resting state (123)I-IMP SPECT could be used instead of the acetazolamide challenge test to evaluate hemodynamic compromise in patients with atherosclerotic occlusive disease. METHODS: Twenty consecutive patients with unilateral internal carotid artery or middle cerebral artery steno-occlusive disease were enrolled...
December 6, 2016: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/27905100/the-severity-of-anaemia-depletes-cerebrovascular-dilatory-reserve-in-children-with-sickle-cell-disease-a-quantitative-magnetic-resonance-imaging-study
#8
Przemyslaw D Kosinski, Paula L Croal, Jackie Leung, Suzan Williams, Isaac Odame, Gregory M T Hare, Manohar Shroff, Andrea Kassner
Overt ischaemic stroke is one of the most devastating complications in children with sickle cell disease (SCD). The compensatory response to anaemia in SCD includes an increase in cerebral blood flow (CBF) by accessing cerebrovascular dilatory reserve. Exhaustion of dilatory reserve secondary to anaemic stress may lead to cerebral ischaemia. The purpose of this study was to investigate CBF and cerebrovascular reactivity (CVR) using magnetic resonance imaging (MRI) in children with SCD and to correlate these with haematological markers of anaemia...
December 1, 2016: British Journal of Haematology
https://www.readbyqxmd.com/read/27888058/cerebrovascular-reactivity-mapping-without-gas-challenges
#9
Peiying Liu, Yang Li, Marco Pinho, Denise C Park, Babu G Welch, Hanzhang Lu
Cerebrovascular reactivity (CVR), the ability of cerebral vessels to dilate or constrict, has been shown to provide valuable information in the diagnosis and treatment evaluation of patients with various cerebrovascular conditions. CVR mapping is typically performed using hypercapnic gas inhalation as a vasoactive challenge while collecting BOLD images, but the inherent need of gas inhalation and the associated apparatus setup present a practical obstacle in applying it in routine clinical use. Therefore, we aimed to develop a new method to map CVR using resting-state BOLD data without the need of gas inhalation...
February 1, 2017: NeuroImage
https://www.readbyqxmd.com/read/27794113/cerebrovascular-reactivity-and-white-matter-integrity
#10
Kevin Sam, Boris Peltenburg, John Conklin, Olivia Sobczyk, Julien Poublanc, Adrian P Crawley, Daniel M Mandell, Lakshmikumar Venkatraghavan, James Duffin, Joseph A Fisher, Sandra E Black, David J Mikulis
OBJECTIVE: To compare the diffusion and perfusion MRI metrics of normal-appearing white matter (NAWM) with and without impaired cerebrovascular reactivity (CVR). METHODS: Seventy-five participants with moderate to severe leukoaraiosis underwent blood oxygen level-dependent CVR mapping using a 3T MRI system with precise carbon dioxide stimulus manipulation. Several MRI metrics were statistically compared between areas of NAWM with positive and negative CVR using one-way analysis of variance with Bonferroni correction for multiple comparisons...
November 29, 2016: Neurology
https://www.readbyqxmd.com/read/27743788/cerebrovascular-reactivity-in-the-caudate-nucleus-lentiform-nucleus-and-thalamus-in-patients-with-carotid-artery-disease
#11
Nolan S Hartkamp, Reinoud P H Bokkers, M J P van Osch, Gert J de Borst, Jeroen Hendrikse
BACKGROUND AND PURPOSE: To assess the effect of unilateral large vessel disease upon the cerebral hemodynamic autoregulatory status in the basal ganglia of patients with steno-occlusive internal carotid artery (ICA) disease. MATERIALS AND METHODS: Twenty-five healthy volunteers and 38 patients with a unilateral symptomatic steno-occlusive ICA lesion and were investigated; 20 with a stenosis >50% and 18 with an occlusion. Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were assessed with pseudo-continuous arterial spin labeling (ASL) magnetic resonance (MR) imaging before and after administration of acetazolamide...
October 12, 2016: Journal of Neuroradiology. Journal de Neuroradiologie
https://www.readbyqxmd.com/read/27722086/mri-based-cerebrovascular-reactivity-using-transfer-function-analysis-reveals-temporal-group-differences-between-patients-with-sickle-cell-disease-and-healthy-controls
#12
Jackie Leung, James Duffin, Joseph A Fisher, Andrea Kassner
OBJECTIVES: Cerebrovascular reactivity (CVR) measures the ability of cerebral blood vessels to change their diameter and, hence, their capacity to regulate regional blood flow in the brain. High resolution quantitative maps of CVR can be produced using blood-oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) in combination with a carbon dioxide stimulus, and these maps have become a useful tool in the clinical evaluation of cerebrovascular disorders. However, conventional CVR analysis does not fully characterize the BOLD response to a stimulus as certain regions of the brain are slower to react to the stimulus than others, especially in disease...
2016: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27693818/correlation-of-homocysteine-with-cerebral-hemodynamic-abnormality-endothelial-dysfunction-markers-and-cognition-impairment-in-patients-with-traumatic-brain-injury
#13
Masoud Hatefi, Someyeh Behzadi, Masoud Moghadas Dastjerdi, Alireza Abootalebi Ghahnavieh, Asghar Rahmani, Fatemeh Mahdizadeh, Mohammad Reza Hafezi Ahmadi, Khairollah Asadollahi
OBJECTIVE: This study aimed to assess any correlation between serum levels of homocysteine (Hcy) and markers of cerebral hemodynamics, endothelial dysfunction, and cognition impairment in patients with traumatic brain injury (TBI). METHODS: By a cross-sectional study, all clinical data and serum levels of homocysteine of 85 TBI patients were collected. The pulsatility indices (PIs) of the middle cerebral artery were recorded by transcranial color-coded Doppler ultrasonography and cerebrovascular reactivity was measured by the increase in middle cerebral artery flow velocity in response to 5% inhaled CO2...
January 2017: World Neurosurgery
https://www.readbyqxmd.com/read/27693197/multiparametric-imaging-of-brain-hemodynamics-and-function-using-gas-inhalation-mri
#14
Peiying Liu, Babu G Welch, Yang Li, Hong Gu, Darlene King, Yihong Yang, Marco Pinho, Hanzhang Lu
Diagnosis and treatment monitoring of cerebrovascular diseases routinely require hemodynamic imaging of the brain. Current methods either only provide part of the desired information or require the injection of multiple exogenous agents. In this study, we developed a multiparametric imaging scheme for the imaging of brain hemodynamics and function using gas-inhalation MRI. The proposed technique uses a single MRI scan to provide simultaneous measurements of baseline venous cerebral blood volume (vCBV), cerebrovascular reactivity (CVR), bolus arrival time (BAT), and resting-state functional connectivity (fcMRI)...
February 1, 2017: NeuroImage
https://www.readbyqxmd.com/read/27619639/assessment-of-cerebrovascular-reserve-in-unilateral-middle-cerebral-artery-stenosis-using-perfusion-ct-and-co2-inhalation-tests
#15
Fen Yang, Wenqian Shi, Jin Shi, Yingqian Zhang, Yanwei Yin, Huiping Shi, Dawei Chen
: Purpose/Aim of the study: Cerebrovascular reactivity (CVR) is an important marker for assessing cerebrovascular disease. This study assessed the CVR by perfusion computed tomography (CT) and CO2 inhalation tests in patients with unilateral middle cerebral artery (MCA) stenosis disease. MATERIALS AND METHODS: Thirty-one patients with unilateral MCA stenosis disease diagnosed by digital subtraction angiography were studied. Patients were divided into two groups according to the degree of stenosis: severe and moderate...
April 2017: International Journal of Neuroscience
https://www.readbyqxmd.com/read/27615115/quantifying-cerebrovascular-reactivity-in-anterior-and-posterior-cerebral-circulations-during-voluntary-breath-holding
#16
Christina D Bruce, Craig D Steinback, Uday V Chauhan, Jamie R Pfoh, Maria Abrosimova, Emily R Vanden Berg, Rachel J Skow, Margie H Davenport, Trevor A Day
What is the central question of this study? We developed and validated a 'stimulus index' (SI; ratio of end-tidal partial pressures of CO2 and O2 ) method to quantify cerebrovascular reactivity (CVR) in anterior and posterior cerebral circulations during breath holding. We aimed to determine whether the magnitude of CVR is correlated with breath-hold duration. What is the main finding and its importance? Using the SI method and transcranial Doppler ultrasound, we found that the magnitude of CVR of the anterior and posterior cerebral circulations is not positively correlated with physiological or psychological break-point during end-inspiratory breath holding...
December 1, 2016: Experimental Physiology
https://www.readbyqxmd.com/read/27598821/simultaneous-multi-slice-sms-acquisition-enhances-the-sensitivity-of-hemodynamic-mapping-using-gas-challenges
#17
Harshan Ravi, Peiying Liu, Shin-Lei Peng, Hanli Liu, Hanzhang Lu
Hemodynamic mapping using gas inhalation has received increasing interest in recent years. Cerebrovascular reactivity (CVR), which reflects the ability of the brain vasculature to dilate in response to a vasoactive stimulus, can be measured by CO2 inhalation with continuous acquisition of blood oxygen level-dependent (BOLD) magnetic resonance images. Cerebral blood volume (CBV) can be measured by O2 inhalation. These hemodynamic mapping methods are appealing because of their absence of gadolinium contrast agent, their ability to assess both baseline perfusion and vascular reserve, and their utility in calibrating the functional magnetic resonance imaging (fMRI) signal...
November 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27566185/changes-in-chorioretinal-blood-flow-velocity-and-cerebral-blood-flow-after-carotid-endarterectomy
#18
Hiroshi Enaida, Shinji Nagata, Atsunobu Takeda, Shintaro Nakao, Yasuhiro Ikeda, Tatsuro Ishibashi
PURPOSE: To investigate the changes in chorioretinal blood flow velocity and cerebral blood after carotid endarterectomy (CEA). METHODS: Nine patients with moderate to severe internal carotid artery stenosis underwent CEA. Chorioretinal blood flow velocity was measured by laser speckle flowgraphy (LSFG), while cerebral blood flow (CBF) was measured by single-photon emission computed tomography (SPECT), on the affected side both before and after CEA. LSFG was evaluated in five areas to determine mean blur rate, while CBF was calculated from regional CBF and cerebrovascular reactivity (CVR), at the middle cerebral artery (MCA) region of each patient...
November 2016: Japanese Journal of Ophthalmology
https://www.readbyqxmd.com/read/27544503/near-infrared-spectroscopy-and-transcranial-sonography-to-evaluate-cerebral-autoregulation-in-middle-cerebral-artery-steno-occlusive-disease
#19
Andreas Oldag, Jens Neumann, Michael Goertler, Hermann Hinrichs, Hans-Jochen Heinze, Andreas Kupsch, Catherine M Sweeney-Reed, Klaus Kopitzki
The measurement of autoregulatory delay by near-infrared spectroscopy (NIRS) has been proposed as an alternative technique to assess cerebral autoregulation, which is routinely assessed via transcranial Doppler sonography (TCD) in most centers. Comparitive studies of NIRS and TCD, however, are largely missing. We investigated whether cerebrovascular reserve (CVR), as assessed via TCD, correlates with the delay of the autoregulatory response to changes in arterial blood pressure (ABP) as assessed by NIRS, i...
November 2016: Journal of Neurology
https://www.readbyqxmd.com/read/27485004/cerebral-vasoconstriction-reactions-and-plasma-levels-of-etbr-et-1-and-enos-in-patients-with-chronic-high-altitude-disease
#20
Shizheng Wu, Guisheng Hao, Shukun Zhang, Dongmei Jiang, Tana Wuren, Junming Luo
The aim of the present study was to examine cerebral vasoconstriction in patients with chronic high altitude disease [cerebrovascular reactivity (CVR)], and to evaluate differences in alterations of brain vascular contractile reactivity of chronic mountain sickness (CMS) patients and healthy controls. Alterations of endothelin (ET) and its receptor, as well as endothelial nitric oxide synthase (eNOS) levels in the plasma were examined to determine the cerebral reservation capacities in CMS patients. Transcranial Doppler ultrasound and carbon dioxide analysis methods were used to detect the CVR variances...
September 2016: Molecular Medicine Reports
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