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Cerebrovascular reactivity, CVR,

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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
#1
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
#2
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...
November 23, 2016: NeuroImage
https://www.readbyqxmd.com/read/27794113/cerebrovascular-reactivity-and-white-matter-integrity
#3
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...
October 28, 2016: Neurology
https://www.readbyqxmd.com/read/27743788/cerebrovascular-reactivity-in-the-caudate-nucleus-lentiform-nucleus-and-thalamus-in-patients-with-carotid-artery-disease
#4
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
#5
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
#6
Masoud Hatefi, Someyeh Behzadi, Masoud Moghadas Dastjerdi, Alireza Abootalebi Ghahnavieh, Asghar Rahmani, Fatemeh Madizadeh, Mohammad Reza Hafezi Ahmadi, Khairollah Asadollahi
OBJECTIVE: This study aimed to assess any correlation between serum levels of homocysteine (Hcy) with markers of cerebral hemodynamic, 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 (PI) of the middle cerebral artery (MCA) were recorded by transcranial color-coded doppler ultrasonography (TCD) and cereberovascular reactivity (CVR)...
September 29, 2016: World Neurosurgery
https://www.readbyqxmd.com/read/27693197/multiparametric-imaging-of-brain-hemodynamics-and-function-using-gas-inhalation-mri
#7
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)...
September 28, 2016: NeuroImage
https://www.readbyqxmd.com/read/27619639/assessment-of-cerebrovascular-reserve-in-unilateral-middle-cerebral-artery-stenosis-using-perfusion-ct-and-co2-inhalation-tests
#8
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 (DSA) were studied. Patients were divided into two groups according to the degree of stenosis: severe and moderate...
September 13, 2016: International Journal of Neuroscience
https://www.readbyqxmd.com/read/27615115/quantifying-cerebrovascular-reactivity-in-anterior-and-posterior-cerebral-circulations-during-voluntary-breath-holding
#9
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
#10
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
#11
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...
August 26, 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
#12
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
#13
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
https://www.readbyqxmd.com/read/27462210/distinct-brain-and-behavioral-benefits-from-cognitive-vs-physical-training-a-randomized-trial-in-aging-adults
#14
Sandra B Chapman, Sina Aslan, Jeffrey S Spence, Molly W Keebler, Laura F DeFina, Nyaz Didehbani, Alison M Perez, Hanzhang Lu, Mark D'Esposito
Insidious declines in normal aging are well-established. Emerging evidence suggests that non-pharmacological interventions, specifically cognitive and physical training, may counter diminishing age-related cognitive and brain functions. This randomized trial compared effects of two training protocols: cognitive training (CT) vs. physical training (PT) on cognition and brain function in adults 56-75 years. Sedentary participants (N = 36) were randomized to either CT or PT group for 3 h/week over 12 weeks. They were assessed at baseline-, mid-, and post-training using neurocognitive, MRI, and physiological measures...
2016: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/27437178/hypercapnic-evaluation-of-vascular-reactivity-in-healthy-aging-and-acute-stroke-via-functional-mri
#15
Ryan V Raut, Veena A Nair, Justin A Sattin, Vivek Prabhakaran
Functional MRI (fMRI) is well-established for the study of brain function in healthy populations, although its clinical application has proven more challenging. Specifically, cerebrovascular reactivity (CVR), which allows the assessment of the vascular response that serves as the basis for fMRI, has been shown to be reduced in healthy aging as well as in a range of diseases, including chronic stroke. However, the timing of when this occurs relative to the stroke event is unclear. We used a breath-hold fMRI task to evaluate CVR across gray matter in a group of acute stroke patients (< 10 days from stroke; N = 22) to address this question...
2016: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27386745/cerebrovascular-and-cognitive-benefits-of-high-oleic-peanut-consumption-in-healthy-overweight-middle-aged-adults
#16
Jayne A Barbour, Peter R C Howe, Jonathan D Buckley, Janet Bryan, Alison M Coates
OBJECTIVE: Peanuts contain bioactive nutrients beneficial for vascular function. This study investigated whether consumption of unsalted peanuts (with skins) would enhance cerebrovascular perfusion and cognitive performance. METHOD: In a randomized crossover trial, 61 volunteers (29 males/32 females, 65 ± 7 years, BMI 31 ± 4 kg/m(2)) consumed their habitual diet ± high-oleic peanuts (56-84 g/day), each for 12 weeks. Nutrient intakes, vascular and cognitive function were assessed at baseline and at the end of each 12-week phase...
July 7, 2016: Nutritional Neuroscience
https://www.readbyqxmd.com/read/27358765/impaired-dynamic-cerebrovascular-response-to-hypercapnia-predicts-development-of-white-matter-hyperintensities
#17
Kevin Sam, John Conklin, Kenneth R Holmes, Olivia Sobczyk, Julien Poublanc, Adrian P Crawley, Daniel M Mandell, Lakshmikumar Venkatraghavan, James Duffin, Joseph A Fisher, Sandra E Black, David J Mikulis
PURPOSE: To evaluate the relationship between both dynamic and steady-state measures of cerebrovascular reactivity (CVR) and the progression of age-related white matter disease. METHODS: Blood oxygen level-dependent (BOLD) MRI CVR scans were acquired from forty-five subjects (age range: 50-90 years, 25 males) with moderate to severe white matter disease, at baseline and one-year follow-up. To calculate the dynamic (τ) and steady-state (ssCVR) components of the BOLD signal response, the PETCO2 signal waveform was convolved with an exponential decay function...
2016: NeuroImage: Clinical
https://www.readbyqxmd.com/read/27352039/development-of-white-matter-hyperintensity-is-preceded-by-reduced-cerebrovascular-reactivity
#18
Kevin Sam, Adrian P Crawley, John Conklin, Julien Poublanc, Olivia Sobczyk, Daniel M Mandell, Lakshmikumar Venkatraghavan, James Duffin, Joseph A Fisher, Sandra E Black, David J Mikulis
OBJECTIVE: White matter hyperintensities (WMH) observed on neuroimaging of elderly individuals are associated with cognitive decline and disability. However, the pathogenesis of WMH remains poorly understood. We observed that regions of reduced cerebrovascular reactivity (CVR) in the white matter of young individuals correspond to the regions most susceptible to WMH in the elderly. This finding prompted us to consider that reduced CVR may play a role in the pathogenesis of WMH. We hypothesized that reduced CVR precedes development of WMH...
August 2016: Annals of Neurology
https://www.readbyqxmd.com/read/27320250/local-cerebral-hypothermia-induced-by-selective-infusion-of-cold-lactated-ringer-s-a-feasibility-study-in-rhesus-monkeys
#19
Bincheng Wang, Di Wu, David Dornbos Iii, Jingfei Shi, Yanhui Ma, Mo Zhang, Yumei Liu, Jian Chen, Yuchuan Ding, Yinghao Luo, Xunming Ji
BACKGROUND AND OBJECTIVE: Hypothermia has shown promise as a neuroprotective strategy for stroke. The use of whole body hypothermia has limited clinical utility due to many severe side effects. Selective brain cooling, or local brain hypothermia, has been previously proposed as an alternative treatment strategy. This study investigated the safety, feasibility, and efficacy of selective brain hypothermia induced by local infusion of ice-cold lactated Ringer's solution in rhesus monkeys...
June 2016: Neurological Research
https://www.readbyqxmd.com/read/27291492/the-bold-cerebrovascular-reactivity-response-to-progressive-hypercapnia-in-young-and-elderly
#20
Alex A Bhogal, Jill B De Vis, Jeroen C W Siero, Esben T Petersen, Peter R Luijten, Jeroen Hendrikse, Marielle E P Philippens, Hans Hoogduin
Blood Oxygenation Level Dependent (BOLD) imaging in combination with vasoactive stimuli can be used to probe cerebrovascular reactivity (CVR). Characterizing the healthy, age-related changes in the BOLD-CVR response can provide a reference point from which to distinguish abnormal CVR from the otherwise normal effects of ageing. Using a computer controlled gas delivery system, we examine differences in BOLD-CVR response to progressive hypercapnia between 16 young (28±3years, 9 female) and 30 elderly subjects (66±4years, 13 female)...
June 9, 2016: NeuroImage
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