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Cerebrovascular reactivity, CVR,

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https://www.readbyqxmd.com/read/29117962/lower-cardiac-index-levels-relate-to-lower-cerebral-blood-flow-in-older-adults
#1
Angela L Jefferson, Dandan Liu, Deepak K Gupta, Kimberly R Pechman, Jennifer M Watchmaker, Elizabeth A Gordon, Swati Rane, Susan P Bell, Lisa A Mendes, L Taylor Davis, Katherine A Gifford, Timothy J Hohman, Thomas J Wang, Manus J Donahue
OBJECTIVE: To assess cross-sectionally whether lower cardiac index relates to lower resting cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) among older adults. METHODS: Vanderbilt Memory & Aging Project participants free of stroke, dementia, and heart failure were studied (n = 314, age 73 ± 7 years, 59% male, 39% with mild cognitive impairment). Cardiac index (liters per minute per meter squared) was quantified from echocardiography. Resting CBF (milliliters per 100 grams per minute) and hypercapnia-induced CVR were quantified from pseudo-continuous arterial spin-labeling MRI...
November 8, 2017: Neurology
https://www.readbyqxmd.com/read/29084064/new-insights-into-cerebral-small-vessel-disease-and-vascular-cognitive-impairment-from-mri
#2
Eric E Smith, Andrew E Beaudin
PURPOSE OF REVIEW: We review recent MRI research that addresses two important challenges in cerebral small vessel disease (SVD) research: early diagnosis, and linking SVD with cognitive impairment. First, we review studies of MRI measurements of blood flow and blood-brain barrier integrity. Second, we review MRI studies identifying neuroimaging correlates of SVD-related cognitive dysfunction, focusing on brain connectivity and white matter microarchitecture. This research is placed in context through discussion of recent recommendations for management of incidentally discovered SVD, and neuroimaging biomarker use in clinical trials...
October 27, 2017: Current Opinion in Neurology
https://www.readbyqxmd.com/read/29066902/effects-of-sevoflurane-versus-propofol-on-cerebrovascular-reactivity-to-carbon-dioxide-during-laparoscopic-surgery
#3
Chunyi Wang, Cheng Ni, Gang Li, Yan Li, Liyuan Tao, Nan Li, Jun Wang, Xiangyang Guo
PURPOSE: Cerebrovascular reactivity to carbon dioxide (CVR-CO2) reflects cerebrovascular reserve capacity, which is important in many brain disorders, including cerebrovascular and Alzheimer's diseases. Meanwhile, there is a relationship between CVR-CO2 and cognitive function. Therefore, the study is aimed at investigating the effects of sevoflurane versus propofol on CVR-CO2 during laparoscopic surgery, as well as the role of CVR-CO2 on cognitive function during perioperative period...
2017: Therapeutics and Clinical Risk Management
https://www.readbyqxmd.com/read/29065769/imaging-of-cerebrovascular-function-in-chronic-traumatic-brain-injury
#4
Franck Amyot, Kimbra Kenney, Carol Moore, Maraglit Harber, L Christine Turtzo, Christian N Shenouda, Erika Silverman, Yunhua Gong, Bao-Xi Qu, Leah Harburg, Hangzang Lu, Eric Wassermann, Ramon Diaz-Arrastia
Traumatic cerebrovascular injury (TCVI) is a common pathologic mechanism of traumatic brain injury (TBI) and presents an attractive target for intervention. The aims of this study were to assess cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) using magnetic resonance imaging (MRI), to assess their value as biomarkers of TCVI in chronic TBI, characterize the spatial distribution of TCVI, and assess the relationships between each biomarker and neuropsychological and clinical assessments. 42 subjects (27 chronic TBI, 15 age and gender-matched healthy volunteers) were studied cross-sectionally...
October 25, 2017: Journal of Neurotrauma
https://www.readbyqxmd.com/read/29036811/sildenafil-improves-vascular-and-metabolic-function-in-patients-with-alzheimer-s-disease
#5
Min Sheng, Hanzhang Lu, Peiying Liu, Yang Li, Harshan Ravi, Shin-Lei Peng, Ramon Diaz-Arrastia, Michael D Devous, Kyle B Womack
BACKGROUND: Alzheimer's disease (AD) is the leading cause of degenerative dementia in the aging population. Patients with AD have alterations in cerebral hemodynamic function including reduced cerebral blood flow (CBF) and cerebral metabolic rate. Therefore, improved cerebrovascular function may be an attractive goal for pharmaceutical intervention in AD. OBJECTIVE: We wished to observe the acute effects of sildenafil on cerebrovascular function and brain metabolism in patients with AD...
October 7, 2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28986176/diffuse-gliomas-exhibit-whole-brain-impaired-cerebrovascular-reactivity
#6
Jorn Fierstra, Christiaan van Niftrik, Marco Piccirelli, Oliver Bozinov, Athina Pangalu, Niklaus Krayenbühl, Antonios Valavanis, Michael Weller, Luca Regli
PURPOSE: Cerebral diffuse gliomas exhibit perilesional impaired cerebrovascular reactivity (CVR), yet the degree of impairment as well as its full spatial extent in the brain remains unknown. With quantitative fMRI, we studied twelve subjects with untreated brain diffuse glioma and twelve healthy controls to assess CVR impairment and determine its distribution throughout the brain. METHODS: In a prospective case-control study, quantitative CVR measurements were derived from BOLD fMRI volumes during standardized iso-oxic changes in carbon dioxide...
October 3, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28967593/measurement-of-cerebrovascular-reactivity-as-blood-oxygen-level-dependent-magnetic-resonance-imaging-signal-response-to-a-hypercapnic-stimulus-in-mechanically-ventilated-patients
#7
Lashmi Venkatraghavan, Julien Poublanc, Jay S Han, Olivia Sobczyk, Casey Rozen, Kevin Sam, James Duffin, David J Mikulis, Joseph A Fisher
BACKGROUND: Impaired cerebrovascular reactivity (CVR) is an important prognostic marker of stroke. Most measures of CVR lack (1) a reproducible vasoactive stimulus and (2) a high time and spatial resolution measure of cerebral blood flow (CBF), particularly for mechanically ventilated patients. The aim of our study was to investigate the feasibility of measuring CVR using sequential gas delivery circuit and gas blender for precise targeting of end-tidal PCO2 (PetCO2), and blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) signal as a surrogate of CBF, in mechanically ventilated patients...
September 26, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28948064/iterative-analysis-of-cerebrovascular-reactivity-dynamic-response-by-temporal-decomposition
#8
Christiaan Hendrik Bas van Niftrik, Marco Piccirelli, Oliver Bozinov, Athina Pangalu, Joseph A Fisher, Antonios Valavanis, Andreas R Luft, Michael Weller, Luca Regli, Jorn Fierstra
OBJECTIVE: To improve quantitative cerebrovascular reactivity (CVR) measurements and CO 2 arrival times, we present an iterative analysis capable of decomposing different temporal components of the dynamic carbon dioxide- Blood Oxygen-Level Dependent (CO 2-BOLD) relationship. EXPERIMENTAL DESIGN: Decomposition of the dynamic parameters included a redefinition of the voxel-wise CO 2 arrival time, and a separation from the vascular response to a stepwise increase in CO 2 (Delay to signal Plateau - DTP) and a decrease in CO 2 (Delay to signal Baseline -DTB)...
September 2017: Brain and Behavior
https://www.readbyqxmd.com/read/28943539/leptomeningeal-collaterals-strongly-correlate-with-reduced-cerebrovascular-reactivity-measured-by-acetazolamide-challenged-single-photon-emission-computed-tomography-using-a-stereotactic-extraction-estimation-analysis-in-patients-with-unilateral-internal-carotid
#9
Takenobu Kunieda, Kosuke Miyake, Hiroki Sakamoto, Yuko Iwasaki, Shin Iida, Satoshi Morise, Kengo Fujita, Masataka Nakamura, Satoshi Kaneko, Hirofumi Kusaka
Objective To assess the correlation between the angiographic appearance of cerebral collateral pathways or the degree of internal carotid artery stenosis (ICAS) and reduced cerebrovascular reactivity (CVR) estimated by single-photon emission computed tomography (SPECT) image analysis in patients with unilateral ICAS. Methods A retrospective analysis was performed in 42 patients with unilateral ICAS who underwent cerebral angiography and acetazolamide-challenged SPECT of the brain. Cerebral blood flow quantitation was performed using the quantitative SPECT/dual-table autoradiography method...
September 25, 2017: Internal Medicine
https://www.readbyqxmd.com/read/28924565/nirs-based-cerebrovascular-regulation-assessment-exercise-and-cerebrovascular-reactivity
#10
Stephanie Miller, Kunal Mitra
Alterations to cerebral blood flow (CBF) have been implicated in diverse neurological conditions. Near-infrared spectroscopy (NIRS)-measured regional cerebral tissue oxygen saturation ([Formula: see text]) provides an estimate of oxygenation of interrogated cerebral volume useful in identifying variations in oxygen supply to cerebral tissue and in monitoring cerebrovascular function. [Formula: see text]-inhalation-based hypercapnic breathing challenges were used to simulate CBF dysregulation, utilizing NIRS to monitor the CBF autoregulatory response...
October 2017: Neurophotonics
https://www.readbyqxmd.com/read/28918088/evaluation-of-cerebrovascular-reactivity-in-subjects-with-and-without-obstructive-sleep-apnea
#11
Clodagh M Ryan, Anne Battisti-Charbonney, Olivia Sobczyk, David J Mikulis, James Duffin, Joseph A Fisher, Lashmi Venkatraghavan
BACKGROUND: Both obstructive sleep apnea (OSA) and altered cerebrovascular reactivity (CVR) are associated with increased stroke risk. Nevertheless, the incidence of abnormal CVR in patients with OSA is uncertain due to the high variability in the way CVR is measured both within and between studies. We hypothesized that a standardized CVR with a consistent vasoactive stimulus and cerebral blood flow (CBF) measure would be reduced in patients with severe OSA compared with healthy controls...
September 13, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28860455/age-differences-in-brain-signal-variability-are-robust-to-multiple-vascular-controls
#12
Douglas D Garrett, Ulman Lindenberger, Richard D Hoge, Claudine J Gauthier
A host of studies support that younger, better performing adults express greater moment-to-moment blood oxygen level-dependent (BOLD) signal variability (SDBOLD) in various cortical regions, supporting an emerging view that the aging brain may undergo a generalized reduction in dynamic range. However, the exact physiological nature of age differences in SDBOLD remains understudied. In a sample of 29 younger and 45 older adults, we examined the contribution of vascular factors to age group differences in fixation-based SDBOLD using (1) a dual-echo BOLD/pseudo-continuous arterial spin labeling (pCASL) sequence, and (2) hypercapnia via a computer-controlled gas delivery system...
August 31, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28756241/rapid-cerebrovascular-reactivity-mapping-enabling-vascular-reactivity-information-to-be-routinely-acquired
#13
Nicholas P Blockley, James W Harkin, Daniel P Bulte
Cerebrovascular reactivity mapping (CVR), using magnetic resonance imaging (MRI) and carbon dioxide as a stimulus, provides useful information on how cerebral blood vessels react under stress. This information has proven to be useful in the study of vascular disorders, dementia and healthy ageing. However, clinical adoption of this form of CVR mapping has been hindered by relatively long scan durations of 7-12 min. By replacing the conventional block presentation of carbon dioxide enriched air with a sinusoidally modulated stimulus, the aim of this study was to investigate whether more clinically acceptable scan durations are possible...
July 26, 2017: NeuroImage
https://www.readbyqxmd.com/read/28724339/influence-of-cerebrovascular-reactivity-on-outcome-of-the-patients-with-%C3%A2-50-symptomatic-unilateral-middle-cerebral-artery-stenosis
#14
Weiqing Zhang, Yanwei Yin, Yingqian Zhang, Fen Yang, Wenqian Shi, Dawei Chen, Chen Song, Huiping Shi, Xuanzhu Zhao, Jin Shi
Purpose/aim of the study: Cerebrovascular reactivity (CVR) reflects the vasodilatory reserve of cerebral resistance vessels, which is an important marker for assessing cerebrovascular disease. The present study is to investigate whether CVR impairment increases adverse long-term outcome risk of patients with ≥ 50% symptomatic unilateral middle cerebral artery (MCA) stenosis (ischemic stroke (IS) or transient ischemic attack (TIA)). MATERIAL AND METHODS: Digital subtraction angiography (DSA) was used to assess the degree of stenosis, and perfusion CT and 5% CO2 inhalation were adopted to evaluate CVR...
August 23, 2017: International Journal of Neuroscience
https://www.readbyqxmd.com/read/28704454/indocyanine-green-kinetics-with-near-infrared-spectroscopy-predicts-cerebral-hyperperfusion-syndrome-after-carotid-artery-stenting
#15
Ichiro Nakagawa, Hun Soo Park, Shohei Yokoyama, Shuichi Yamada, Yasushi Motoyama, Young Su Park, Takeshi Wada, Kimihiko Kichikawa, Hiroyuki Nakase
BACKGROUND: Cerebral hyperperfusion syndrome (HPS) is a potentially life-threatening complication following carotid artery stenting (CAS) and carotid endoarterectomy (CEA). Early prediction and treatment of patients at risk for HPS are required in patients undergoing CAS because HPS occurs significantly earlier after CAS than CEA. Near-infrared spectroscopy (NIRS) is often used for monitoring, and indocyanine green (ICG) kinetics by NIRS (ICG-NIRS) can detect reductions in cerebral perfusion in patients with acute stroke...
2017: PloS One
https://www.readbyqxmd.com/read/28615420/insulin-resistance-among-obese-middle-aged-is-associated-with-decreased-cerebrovascular-reactivity
#16
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)...
July 18, 2017: Neurology
https://www.readbyqxmd.com/read/28560160/application-of-calibrated-fmri-in-alzheimer-s-disease
#17
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
#18
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
#19
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
#20
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
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