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Cerebrovascular reactivity, CVR,

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
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
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 SPECT using a subjective 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. Preoperative resting asymmetry index (CBF ratio from the affected to unaffected hemisphere) and cerebrovascular reactivity (CVR) to acetazolamide were measured by N-isopropyl-p-[123 I]-iodoamphetamine SPECT using the SEE and ROI method in 84 patients...
March 7, 2018: Journal of Neuroradiology. Journal de Neuroradiologie
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 (CMRO 2 ) 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 CMRO 2 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...
February 14, 2018: NeuroImage
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)...
February 13, 2018: NeuroImage
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...
February 13, 2018: Magnetic Resonance Imaging
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
Lennart Geurts, Alex Bhogal, Jeroen Siero, Peter Luijten, Geert Jan Biessels, Jaco 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...
February 2, 2018: NeuroImage
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 (15O-)H2O 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)...
January 25, 2018: Stroke; a Journal of Cerebral Circulation
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
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
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
Jill N Barnes, Ronée E Harvey, Kathleen B Miller, Muthuvel Jayachandran, Katherine R Malterer, Brian D Lahr, Kent R Bailey, Michael J Joyner, Virginia M Miller
Cerebrovascular reactivity (CVR) is reduced in patients with cognitive decline. Women with a history of preeclampsia are at increased risk for cognitive decline. This study examined an association between pregnancy history and CVR using a subgroup of 40 age- and parity-matched pairs of women having histories of preeclampsia (n=27) or normotensive pregnancy (n=29) and the association of activated blood elements with CVR. Middle cerebral artery velocity was measured by Doppler ultrasound before and during hypercapnia to assess CVR...
November 20, 2017: Hypertension
Margarita Abi Zeid Daou, Brian D Boyd, Manus J Donahue, Kimberly Albert, Warren D Taylor
Vascular pathology is common in late-life depression, contributing to changes in cerebral function. We examined whether late-life depression was associated with differences in cerebral blood flow (CBF) and whether such differences were related to vascular risk and cerebrovascular pathology, specifically white matter hyperintensity (WMH) volumes. Twenty-three depressed elders and 20 age- and sex-matched elders with no psychiatric history completed cranial 3T MRI. MRI procedures included a pseudo-continuous Arterial Spin Labeling (pcASL) acquisition obtained while on room air and during a hypercapnia challenge allowing for calculation of cerebrovascular reactivity (CVR)...
February 2018: Journal of Psychiatric Research
Ichiro Nakagawa, Shohei Yokoyama, Daisuke Wajima, Fumihiko Nishimura, Shuichi Yamada, Hiroshi Yokota, Yasushi Motoyama, Young Su Park, Takeshi Wada, Kimihiko Kichikawa, Hiroyuki Nakase
Cerebral hyperperfusion syndrome (CHS) is a serious complication following carotid artery stenting (CAS), but definitive early prediction of CHS has not been established. Here, we evaluated whether indocyanine green kinetics and near-infrared spectroscopy (ICG-NIRS) with hyperventilation (HV) and the breath-holding (BH) test can predict hyperperfusion phenomenon after CAS. The blood flow index (BFI) ratio during HV and BH was prospectively monitored using ICG-NIRS in 66 patients scheduled to undergo CAS. Preoperative cerebrovascular reactivity (CVR) and the postoperative asymmetry index (AI) were also assessed with single-photon emission computed tomography before and after CAS and the correlation with the BFI HV/rest ratio, BFI BH/rest ratio was evaluated...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
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...
December 5, 2017: Neurology
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...
February 2018: Current Opinion in Neurology
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
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
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...
2017: Journal of Alzheimer's Disease: JAD
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