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Cerebrovascular reactivity, CVR,

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https://www.readbyqxmd.com/read/28615420/insulin-resistance-among-obese-middle-aged-is-associated-with-decreased-cerebrovascular-reactivity
#1
Olivia H Frosch, Po Lai Yau, Ricardo S Osorio, Henry Rusinek, Pippa Storey, Antonio Convit
OBJECTIVE: To evaluate differences in cerebrovascular reactivity (CVR) to mild hypercapnia in obese/overweight individuals with and without insulin resistance (IR) compared to comparable lean controls. METHODS: A total of 60 cognitively normal participants (20 lean controls and 24 obese/overweight individuals with and 16 without IR) were evaluated using a high spatial resolution arterial spin labeling MRI technique at rest and during mild hypercapnia. We analyzed group differences in CVR in cerebral cortex and ascertained the relationships between CVR, IR, and body mass index (BMI)...
June 14, 2017: Neurology
https://www.readbyqxmd.com/read/28560160/application-of-calibrated-fmri-in-alzheimer-s-disease
#2
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/28529871/subtle-alterations-in-cerebrovascular-reactivity-in-mild-cognitive-impairment-detected-by-graph-theoretical-analysis-and-not-by-the-standard-approach
#3
Carlos A Sánchez-Catasús, Gretel Sanabria-Diaz, Antoon Willemsen, Eduardo Martinez-Montes, Juan Samper-Noa, Angel Aguila-Ruiz, Ronald Boellaard, Peter De Deyn, Rudi A J O Dierckx, Lester Melie-Garcia
There is growing support that cerebrovascular reactivity (CVR) in response to a vasodilatory challenge, also defined as the cerebrovascular reserve, is reduced in Alzheimer's disease dementia. However, this is less clear in patients with mild cognitive impairment (MCI). The current standard analysis may not reflect subtle abnormalities in CVR. In this study, we aimed to investigate vasodilatory-induced changes in the topology of the cerebral blood flow correlation (CBFcorr) network to study possible network-related CVR abnormalities in MCI...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28487157/cerebrovascular-reactivity-measured-by-functional-magnetic-resonance-imaging-during-breath-hold-challenge-a-systematic-review
#4
REVIEW
Adam L Urback, Bradley J MacIntosh, Benjamin I Goldstein
Cerebrovascular reactivity (CVR) is the cerebral hemodynamic response to a vasoactive substance. Breath-hold (BH) induced CVR has the advantage of being non-invasive and easy to implement during magnetic resonance imaging (MRI). We systematically reviewed the literature regarding MRI measurement of BH induced CVR. The literature was searched using MEDLINE with the search terms breath-hold; and MRI or cerebrovascular reactivity. The search yielded 2244 results and 54 articles were included. Between-group comparisons have found that CVR was higher among healthy controls than patients with various pathologies (e...
August 2017: Neuroscience and Biobehavioral Reviews
https://www.readbyqxmd.com/read/28355354/cerebral-blood-flow-and-vasoreactivity-in-aging-an-arterial-spin-labeling-study
#5
R F Leoni, I A F Oliveira, O M Pontes-Neto, A C Santos, J P Leite
Regional cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) in young and elderly participants were assessed using pulsed arterial spin labeling (ASL) and blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) techniques in combination with inhalation of CO2. Pulsed ASL and BOLD-MRI were acquired in seventeen asymptomatic volunteers (10 young adults, age: 30±7 years; 7 elderly adults, age: 64±8 years) with no history of diabetes, hypertension, and neurological diseases. Data from one elderly participant was excluded due to the incorrigible head motion...
March 23, 2017: Brazilian Journal of Medical and Biological Research, Revista Brasileira de Pesquisas Médicas e Biológicas
https://www.readbyqxmd.com/read/28351960/pathogenesis-of-white-matter-changes-in-cerebral-small-vessel-diseases-beyond-vessel-intrinsic-mechanisms
#6
REVIEW
Anne Joutel, Hugues Chabriat
Cerebral small vessel diseases (SVDs) are a leading cause of age and hypertension-related stroke and dementia. The salient features of SVDs visible on conventional brain magnetic resonance images include white matter hyperintensities (WMHs) on T2-weighted images, small infarcts, macrohemorrhages, dilated perivascular spaces, microbleeds and brain atrophy. Among these, WMHs are the most common and often the earliest brain tissue changes. Moreover, over the past two decades, large population- and patient-based studies have established the clinical importance of WMHs, notably with respect to cognitive and motor disturbances...
April 25, 2017: Clinical Science (1979-)
https://www.readbyqxmd.com/read/28324779/frontocingulate-cerebral-blood-flow-and-cerebrovascular-reactivity-associated-with-antidepressant-response-in-late-life-depression
#7
Margarita Abi Zeid Daou, Brian D Boyd, Manus J Donahue, Kimberly Albert, Warren D Taylor
BACKGROUND: Vascular pathology is common in late-life depression (LLD) and may contribute to alterations in cerebral blood flow (CBF) and cerebrovascular reactivity (CVR). In turn, such hemodynamic deficits may adversely affect brain function and clinical course. The goal of this study was to examine whether altered cerebral hemodynamics in depressed elders predicted antidepressant response. METHODS: 21 depressed elders completed cranial 3T MRI, including a pseudo-continuous Arterial Spin Labeling (pcASL) acquisition on both room air and during a hypercapnia challenge...
June 2017: Journal of Affective Disorders
https://www.readbyqxmd.com/read/28323164/mapping-the-pharmacological-modulation-of-brain-oxygen-metabolism-the-effects-of-caffeine-on-absolute-cmro2-measured-using-dual-calibrated-fmri
#8
Alberto Merola, Michael A Germuska, Esther Ah Warnert, Lewys Richmond, Daniel Helme, Sharmila Khot, Kevin Murphy, Peter J Rogers, Judith E Hall, Richard G Wise
This study aims to map the acute effects of caffeine ingestion on grey matter oxygen metabolism and haemodynamics with a novel MRI method. Sixteen healthy caffeine consumers (8 males, age=24.7±5.1) were recruited to this randomised, double-blind, placebo-controlled study. Each participant was scanned on two days before and after the delivery of an oral caffeine (250mg) or placebo capsule. Our measurements were obtained with a newly proposed estimation approach applied to data from a dual calibration fMRI experiment that uses hypercapnia and hyperoxia to modulate brain blood flow and oxygenation...
March 18, 2017: NeuroImage
https://www.readbyqxmd.com/read/28279732/intra-individual-variability-in-cerebrovascular-and-respiratory-chemosensitivity-can-we-characterize-a-chemoreflex-reactivity-profile
#9
Kennedy J Borle, Jamie R Pfoh, Lindsey M Boulet, Maria Abrosimova, Michael M Tymko, Rachel J Skow, Amy Varner, Trevor A Day
Intra-individual variability in the magnitude of human cerebrovascular and respiratory chemoreflex responses is largely unexplored. By comparing response magnitudes of cerebrovascular CO2 reactivity (CVR; middle and posterior cerebral arteries; MCA, PCA), central (CCR; CO2) and peripheral respiratory chemoreflexes (PCR; CO2 and O2), we tested the hypothesis that a within-individual reactivity magnitude profile could be characterized. The magnitudes of CVR and CCR were tested with hyperoxic rebreathing and PCR magnitudes were tested through transient respiratory tests (TT-CO2, hypercapnia; TT-N2, hypoxia)...
March 6, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28277379/anesthesia-and-concussion
#10
Robert C Tasker
PURPOSE OF REVIEW: As clinicians preparing patients for general anesthesia, should we consider the possibility of concussion in our elective operative patients? If so, why is this necessary? Is it possible that exposure to an anesthetic is detrimental to recovery from concussion? If so, what should we do about the imperative/urgency for surgery? No answers are promised in this review. Rather, the focus is on the questions and approaches taken in the recent literature, as well as highlighting a need for more research...
June 2017: Current Opinion in Anaesthesiology
https://www.readbyqxmd.com/read/28258787/cerebrovascular-reactivity-and-intellectual-outcome-in-childhood-stroke-with-transient-cerebral-arteriopathy
#11
Nomazulu Dlamini, Ivanna Yau, Robyn Westmacott, Manohar Shroff, Derek Armstrong, William Logan, David Mikulis, Gabrielle deVeber, Andrea Kassner
BACKGROUND: Hypercapnic-challenge blood oxygen level-dependent magnetic resonance imaging cerebrovascular reactivity (CVR), measures the regional perfusion response to altered carbon dioxide. CVR correlates with the tissue-level microvascular dysfunction and ischemic risk. Among children with arterial ischemic stroke, transient cerebral arteriopathy (TCA) is a frequent, nonprogressive unilateral intracranial arteriopathy, which typically results in basal ganglia infarction and chronic cerebral artery stenosis...
January 7, 2017: Pediatric Neurology
https://www.readbyqxmd.com/read/28152241/invalidation-of-fmri-experiments-secondary-to-neurovascular-uncoupling-in-patients-with-cerebrovascular-disease
#12
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
#13
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
#14
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
#15
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
#16
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...
December 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
#17
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
#18
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...
March 2017: 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
#19
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...
January 2017: British Journal of Haematology
https://www.readbyqxmd.com/read/27888058/cerebrovascular-reactivity-mapping-without-gas-challenges
#20
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
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