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Cerebrovascular reactivity, CVR,

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https://www.readbyqxmd.com/read/29726891/understanding-the-role-of-the-perivascular-space-in-cerebral-small-vessel-disease
#1
Rosalind Brown, Helene Benveniste, Sandra E Black, Serge Charpak, Martin Dichgans, Anne Joutel, Maiken Nedergaard, Kenneth J Smith, Berislav V Zlokovic, Joanna M Wardlaw
Small vessel diseases are a group of disorders that result from pathological alteration of the small blood vessels in the brain, including the small arteries, capillaries and veins. Of the 35-36 million people that are estimated to suffer from dementia worldwide, up to 65% have an SVD component. Furthermore, SVD causes 20-25% of strokes, worsens outcome after stroke and is a leading cause of disability, cognitive impairment and poor mobility. Yet the underlying cause(s) of SVD are not fully understood.Magnetic resonance imaging (MRI) has confirmed enlarged perivascular spaces (PVS) as a hallmark feature of SVD...
May 2, 2018: Cardiovascular Research
https://www.readbyqxmd.com/read/29687019/phosphodiesterase-5-inhibition-potentiates-cerebrovascular-reactivity-in-chronic-traumatic-brain-injury
#2
Kimbra Kenney, Franck Amyot, Carol Moore, Margalit Haber, L Christine Turtzo, Christian Shenouda, Erika Silverman, Yunhua Gong, Bao-Xi Qu, Leah Harburg, Eric M Wassermann, Hanzhang Lu, Ramon Diaz-Arrastia
Background: Traumatic cerebrovascular injury (TCVI), a common consequence of traumatic brain injury (TBI), presents an attractive therapeutic target. Because phosphodiesterase-5 (PDE5) inhibitors potentiate the action of nitric oxide (NO) produced by endothelial cells, they are candidate therapies for TCVI. This study aims to: (1) measure cerebral blood flow (CBF), cerebrovascular reactivity (CVR), and change in CVR after a single dose of sildenafil (ΔCVR) in chronic TBI compared to uninjured controls; (2) examine the safety and tolerability of 8-week sildenafil administration in chronic symptomatic moderate/severe TBI patients; and as an exploratory aim, (3) assess the effect of an 8-week course of sildenafil on chronic TBI symptoms...
April 2018: Annals of Clinical and Translational Neurology
https://www.readbyqxmd.com/read/29681886/importance-of-collateralization-in-patients-with-large-artery-intracranial-occlusive-disease-long-term-longitudinal-assessment-of-cerebral-hemodynamic-function
#3
Larissa McKetton, Lakshmikumar Venkatraghavan, Julien Poublanc, Olivia Sobczyk, Adrian P Crawley, Casey Rosen, Frank L Silver, James Duffin, Joseph A Fisher, David J Mikulis
Patients with large artery intracranial occlusive disease (LAICOD) are at risk for both acute ischemia and chronic hypoperfusion. Collateral circulation plays an important role in prognosis, and imaging plays an essential role in diagnosis, treatment planning, and prognosis of patients with LAICOD. In addition to standard structural imaging, assessment of cerebral hemodynamic function is important to determine the adequacy of collateral supply. Among the currently available methods of assessment of cerebral hemodynamic function, measurement of cerebrovascular reactivity (CVR) using blood oxygen level-dependent (BOLD) MRI and precisely controlled CO2 has shown to be a safe, reliable, reproducible, and clinically useful method for long-term assessment of patients...
2018: Frontiers in Neurology
https://www.readbyqxmd.com/read/29649969/magnetic-resonance-imaging-for-assessment-of-cerebrovascular-reactivity-and-its-relationship-to-cognition-a-systematic-review
#4
Sarah J Catchlove, Andrew Pipingas, Matthew E Hughes, Helen Macpherson
BACKGROUND: Cerebrovascular reactivity (CVR) refers to the responsiveness of cerebral vasculature to vasoactive stimuli. CVR is an indicator of brain health and can be assessed using vasodilatory techniques and magnetic resonance imaging (MRI). Using such approaches, some researchers have explored the relationship between CVR and cognition; here we systematically review this work. RESULTS: We extracted information pertaining to: (1) study location and design, participant characteristics, sample sizes, (2) design of vascular challenge, end-tidal CO 2 (etCO 2 ) concentrations (if applicable), (3) MRI protocol, (4) cognitive assessment, (5) CVR values, and outcomes of statistical analyses with cognitive tests...
April 12, 2018: BMC Neuroscience
https://www.readbyqxmd.com/read/29593520/iclinfmri-software-for-integrating-functional-mri-techniques-in-presurgical-mapping-and-clinical-studies
#5
Ai-Ling Hsu, Ping Hou, Jason M Johnson, Changwei W Wu, Kyle R Noll, Sujit S Prabhu, Sherise D Ferguson, Vinodh A Kumar, Donald F Schomer, John D Hazle, Jyh-Horng Chen, Ho-Ling Liu
Task-evoked and resting-state (rs) functional magnetic resonance imaging (fMRI) techniques have been applied to the clinical management of neurological diseases, exemplified by presurgical localization of eloquent cortex, to assist neurosurgeons in maximizing resection while preserving brain functions. In addition, recent studies have recommended incorporating cerebrovascular reactivity (CVR) imaging into clinical fMRI to evaluate the risk of lesion-induced neurovascular uncoupling (NVU). Although each of these imaging techniques possesses its own advantage for presurgical mapping, a specialized clinical software that integrates the three complementary techniques and promptly outputs the analyzed results to radiology and surgical navigation systems in a clinical format is still lacking...
2018: Frontiers in Neuroinformatics
https://www.readbyqxmd.com/read/29574034/cerebrovascular-reactivity-cvr-mri-with-co2-challenge-a-technical-review
#6
Peiying Liu, Jill De Vis, Hanzhang Lu
Cerebrovascular reactivity (CVR) is an indicator of cerebrovascular reserve and provides important information about vascular health in a range of brain conditions and diseases. Unlike steady-state vascular parameters, such as cerebral blood flow (CBF) and cerebral blood volume (CBV), CVR measures the ability of cerebral vessels to dilate or constrict in response to challenges or maneuvers. Therefore, CVR mapping requires a physiological challenge while monitoring the corresponding hemodynamic changes in the brain...
March 21, 2018: NeuroImage
https://www.readbyqxmd.com/read/29567504/age-related-changes-in-cerebrovascular-reactivity-and-their-relationship-to-cognition-a-four-year-longitudinal-study
#7
Shin-Lei Peng, Xi Chen, Yang Li, Karen M Rodrigue, Denise C Park, Hanzhang Lu
Although cerebrovascular factors are the second leading cause of cognitive impairment and dementia in elderly, the precise spatial and temporal trajectories of vascular decline in aging have not been fully characterized. With an advanced cerebrovascular reactivity (CVR) MRI technique that specifically informs vascular stiffness and dilatory ability of cerebral vessels, we present four-year longitudinal CVR data measured in 116 healthy individuals (20-88 years of age). Our data revealed a spatial heterogeneity in vascular decline in aging (p = 0...
March 19, 2018: NeuroImage
https://www.readbyqxmd.com/read/29565505/changes-in-cerebrovascular-reactivity-in-healthy-adults-after-acute-exposure-to-high-altitude
#8
J Liu, S-K Zhang, J-M Luo, Q-Z Hu, W-Y Ma, S-Z Wu
OBJECTIVE:   To study changes in the cerebrovascular reactivity (CVR) at different altitude area in healthy adults. SUBJECTS AND METHODS: CVR was tested using transcranial Doppler combined with CO2 inhalation, near-infrared spectroscopy (NIRS) was used to detect the regional cerebral oxygen saturation (rScO2). Blood samples were collected, and the vasoactive substances in serum were detected using the enzyme-linked immunosorbent assay. In this study, 59 healthy adults were divided into 3 groups: low altitude group, medium altitude group and high altitude group...
March 2018: European Review for Medical and Pharmacological Sciences
https://www.readbyqxmd.com/read/29529102/regional-resting-state-perfusion-variability-and-delayed-cerebrovascular-uniform-reactivity-in-subjects-with-chronic-carotid-artery-stenosis
#9
Arkadiusz Szarmach, Mariusz Kaszubowski, Agnieszka Sabisz, Andrzej F Frydrychowski, Grzegorz Halena, Maciej Piskunowicz, Jarosław Dzierzanowski, Michał Studniarek, Edyta Szurowska, Pawel J Winklewski
The aim of this study was to assess regional perfusion at baseline and regional cerebrovascular resistance (CVR) to delayed acetazolamide challenge in subjects with chronic carotid artery stenosis. Sixteen patients (ten males) aged 70.94±7.71 with carotid artery stenosis ≥ 90% on the ipsilateral side and ≤ 50% on the contralateral side were enrolled into the study. In all patients, two computed tomography perfusion examinations were carried out; the first was performed before acetazolamide administration and the second 60 minutes after injection...
March 12, 2018: Acta Biochimica Polonica
https://www.readbyqxmd.com/read/29528447/clinical-use-of-cerebrovascular-compliance-imaging-to-evaluate-revascularization-in-patients-with-moyamoya
#10
Jennifer M Watchmaker, Blaise deB Frederick, Matthew R Fusco, Larry T Davis, Meher R Juttukonda, Sarah K Lants, Howard S Kirshner, Manus J Donahue
BACKGROUND: Surgical revascularization is often performed in patients with moyamoya, however routine tools for efficacy evaluation are underdeveloped. The gold standard is digital subtraction angiography (DSA); however, DSA requires ionizing radiation and procedural risk, and therefore is suboptimal for routine surveillance of parenchymal health. OBJECTIVE: To determine whether parenchymal vascular compliance measures, obtained noninvasively using magnetic resonance imaging (MRI), provide surrogates to revascularization success by comparing measures with DSA before and after surgical revascularization...
March 8, 2018: Neurosurgery
https://www.readbyqxmd.com/read/29524498/objective-evaluation-of-cerebrovascular-reactivity-for-acetazolamide-predicts-cerebral-hyperperfusion-after-carotid-artery-stenting-comparison-with-region-of-interest-methods
#11
Kouichi Misaki, Naoyuki Uchiyama, Anri Inaki, Seigo Kinuya, Iku Nambu, Tomoya Kamide, Masanao Mohri, Yasuhiko Hayashi, Mitsutoshi Nakada
BACKGROUND AND PURPOSE: Hemodynamic impairments are considered risk factors of cerebral hyperperfusion after carotid artery stenting (CAS); measurement by Single-photon emission computed tomography (SPECT) using a subjective region of interest (ROI) method lacks consistency and reproducibility. MATERIALS AND METHODS: The present study compared objective perfusion analysis (stereotactic extraction estimation [SEE] method) with the ROI method for preoperative SPECT to predict the hyperperfusion phenomenon (HPP) after CAS...
March 7, 2018: Journal of Neuroradiology. Journal de Neuroradiologie
https://www.readbyqxmd.com/read/29454105/assessing-the-repeatability-of-absolute-cmro-2-oef-and-haemodynamic-measurements-from-calibrated-fmri
#12
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 (CMRO2 ) 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 CMRO2 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...
June 2018: NeuroImage
https://www.readbyqxmd.com/read/29452265/characterizing-the-modulation-of-resting-state-fmri-metrics-by-baseline-physiology
#13
Powell P W Chu, Ali M Golestani, Jonathan B Kwinta, Yasha B Khatamian, J Jean Chen
The blood-oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) signal is commonly used to assess functional connectivity across brain regions, particularly in the resting state (rs-fMRI). However, the BOLD fMRI signal is not merely a representation of neural activity, but a combination of neural activity and vascular response. These aspects of the BOLD signal are easily influenced by systemic physiology, potentially biasing BOLD-based functional connectivity measurements. In this work, we focus on the following physiological modulators of the BOLD signal: cerebral blood flow (CBF), venous blood oxygenation, and cerebrovascular reactivity (CVR)...
June 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
#14
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-oxygenation-level-dependent (BOLD) cerebrovascular reactivity (CVR) has also been used to optimize task evoked BOLD signal changes...
June 2018: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/29432609/impaired-cerebral-hemodynamics-and-frailty-in-patients-with-cardiovascular-disease
#15
Miri Lutski, Salo Haratz, Galit Weinstein, Uri Goldbourt, David Tanne
Background: Recent studies suggest that impaired cerebrovascular reactivity (CVR), a marker of cerebral microvascular damage, is associated with a higher risk of stroke, cognitive decline and mortality. We tested whether abnormal cerebrovascular status is associated with late-life frailty among men with pre-existing cardiovascular disease. Methods: A subset of 327 men (mean age at baseline 56.7±6.5 years) who previously participated in the Bezafibrate Infarction Prevention (BIP) trial (1990-1997) and then in the BIP Neurocognitive study underwent a neurovascular evaluation 14...
February 8, 2018: Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
https://www.readbyqxmd.com/read/29408324/vascular-reactivity-in-small-cerebral-perforating-arteries-with-7-t-phase-contrast-mri-a-proof-of-concept-study
#16
Lennart J Geurts, Alex A Bhogal, Jeroen C W Siero, Peter R Luijten, Geert Jan Biessels, Jaco J M Zwanenburg
Existing cerebrovascular reactivity (CVR) techniques assess flow reactivity in either the largest cerebral vessels or at the level of the parenchyma. We examined the ability of 2D phase contrast MRI at 7 T to measure CVR in small cerebral perforating arteries. Blood flow velocity in perforators was measured in 10 healthy volunteers (mean age 26 years) using a 7 T MR scanner, using phase contrast acquisitions in the semioval center (CSO), the basal ganglia (BG) and the middle cerebral artery (MCA). Changes in flow velocity in response to a hypercapnic breathing challenge were assessed, and expressed as the percentual increase of flow velocity as a function of the increase in end tidal partial pressure of CO2 ...
May 15, 2018: NeuroImage
https://www.readbyqxmd.com/read/29371433/staging-hemodynamic-failure-with-blood-oxygen-level-dependent-functional-magnetic-resonance-imaging-cerebrovascular-reactivity-a-comparison-versus-gold-standard-15-o-h-2-o-positron-emission-tomography
#17
COMPARATIVE STUDY
Jorn Fierstra, Christiaan van Niftrik, Geoffrey Warnock, Susanne Wegener, Marco Piccirelli, Athina Pangalu, Giuseppe Esposito, Antonios Valavanis, Alfred Buck, Andreas Luft, Oliver Bozinov, Luca Regli
BACKGROUND AND PURPOSE: Increased stroke risk correlates with hemodynamic failure, which can be assessed with (15 O-)H2 O positron emission tomography (PET) cerebral blood flow (CBF) measurements. This gold standard technique, however, is not established for routine clinical imaging. Standardized blood oxygen-level-dependent (BOLD) functional magnetic resonance imaging+CO2 is a noninvasive and potentially widely applicable tool to assess whole-brain quantitative cerebrovascular reactivity (CVR)...
March 2018: Stroke; a Journal of Cerebral Circulation
https://www.readbyqxmd.com/read/29282326/neurocognitive-functioning-and-cerebrovascular-reactivity-after-carotid-endarterectomy
#18
Simona Lattanzi, Luciano Carbonari, Gabriele Pagliariccio, Marco Bartolini, Claudia Cagnetti, Giovanna Viticchi, Laura Buratti, Leandro Provinciali, Mauro Silvestrini
OBJECTIVE: To evaluate in patients with TIA and ipsilateral high-grade internal carotid artery (ICA) stenosis whether changes in cognitive performance and cerebral hemodynamics occurred after carotid endarterectomy (CEA) and to explore their relationship. METHODS: Participants were patients who underwent CEA, had TIA within the last 6 months, and had an ipsilateral severe ICA stenosis. Coloured Progressive Matrices (CPM) plus Complex Figure Copy Test (CFCT) and phonemic (ph) plus categorical (ca) Verbal Fluency (VF) tests were performed to assess right and left hemisphere cognitive functions, respectively...
January 23, 2018: Neurology
https://www.readbyqxmd.com/read/29217405/a-novel-perspective-to-calibrate-temporal-delays-in-cerebrovascular-reactivity-using-hypercapnic-and-hyperoxic-respiratory-challenges
#19
Allen A Champagne, Alex A Bhogal, Nicole S Coverdale, Clarisse I Mark, Douglas J Cook
Redistribution of blood flow across different brain regions, arising from the vasoactive nature of hypercapnia, can introduce errors when examining cerebrovascular reactivity (CVR) response delays. In this study, we propose a novel analysis method to characterize hemodynamic delays in the blood oxygen level dependent (BOLD) response to hypercapnia, and hyperoxia, as a way to provide insight into transient differences in vascular reactivity between cortical regions, and across tissue depths. A pseudo-continuous arterial spin labeling sequence was used to acquire BOLD and cerebral blood flow simultaneously in 19 healthy adults (12 F; 20 ± 2 years) during boxcar CO2 and O2 gas inhalation paradigms...
December 4, 2017: NeuroImage
https://www.readbyqxmd.com/read/29214780/mismatch-between-tof-mr-angiography-and-ct-angiography-of-the-middle-cerebral-artery-may-be-a-critical-sign-in-cerebrovascular-dynamics
#20
Keiji Igase, Michiya Igase, Ichiro Matsubara, Kazuhiko Sadamoto
PURPOSE: Although time-of-flight (TOF)-magnetic resonance angiography (MRA) can clearly depict intracranial arteries, the arterial flow of middle cerebral artery (MCA) is occasionally not detected. We evaluated this phenomenon with reference to cerebrovascular dynamics. MATERIALS AND METHODS: Seventeen patients with suspected occlusion of MCA or internal carotid artery on TOF-MRA were enrolled. All patients underwent CT angiography (CTA) and quantitative cerebral blood flow (CBF) examination for measurement of resting CBF and cerebrovascular reactivity (CVR)...
January 2018: Yonsei Medical Journal
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