scholarly journals Comparison of CO2 in Air Versus Carbogen for the Measurement of Cerebrovascular Reactivity with Magnetic Resonance Imaging

2013 ◽  
Vol 33 (11) ◽  
pp. 1799-1805 ◽  
Author(s):  
Hannah V Hare ◽  
Michael Germuska ◽  
Michael E Kelly ◽  
Daniel P Bulte
Keyword(s):  
Arterial Spin Labeling ◽  
Spin Labeling ◽  
Blood Oxygen Level Dependent ◽  
Cerebrovascular Reactivity ◽  
Blood Oxygen ◽  
Resonance Imaging ◽  
Blood Oxygen Level ◽  
Bold Imaging ◽  
Flow Response ◽  
Alternative Stimulus

Measurement of cerebrovascular reactivity (CVR) can give valuable information about existing pathology and the risk of adverse events, such as stroke. A common method of obtaining regional CVR values is by measuring the blood flow response to carbon dioxide (CO2)-enriched air using arterial spin labeling (ASL) or blood oxygen level-dependent (BOLD) imaging. Recently, several studies have used carbogen gas (containing only CO2 and oxygen) as an alternative stimulus. A direct comparison was performed between CVR values acquired by ASL and BOLD imaging using stimuli of (1) 5% CO2 in air and (2) 5% CO2 in oxygen (carbogen-5). Although BOLD and ASL CVR values are shown to be correlated for CO2 in air (mean response 0.11 ± 0.03% BOLD, 4.46 ± 1.80% ASL, n = 16 hemispheres), this correlation disappears during a carbogen stimulus (0.36 ± 0.06% BOLD, 4.97 ± 1.30% ASL). It is concluded that BOLD imaging should generally not be used in conjunction with a carbogen stimulus when measuring CVR, and that care must be taken when interpreting CVR as measured by ASL, as values obtained from different stimuli (CO2 in air versus carbogen) are not directly comparable.

scholarly journals Arterial Spin Labeling and Blood Oxygen Level-Dependent MRI Cerebrovascular Reactivity in Cerebrovascular Disease: A Systematic Review and Meta-Analysis

2016 ◽  
Vol 42 (3-4) ◽  
pp. 288-307 ◽  
Author(s):  
Diederik P.J. Smeeing ◽  
Jeroen Hendrikse ◽  
Esben T. Petersen ◽  
Manus J. Donahue ◽  
Jill B. de Vis
Keyword(s):  
Cerebrovascular Disease ◽  
Arterial Spin Labeling ◽  
Meta Analysis ◽  
Spin Labeling ◽  
Blood Oxygen Level Dependent ◽  
Cerebrovascular Reactivity ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Blood Oxygen Level ◽  
Occlusive Vascular Disease

Background: The cerebrovascular reactivity (CVR) results of blood oxygen level-dependent (BOLD) and arterial spin labeling (ASL) MRI studies performed in patients with cerebrovascular disease (steno-occlusive vascular disease or stroke) were systematically reviewed. Summary: Thirty-one articles were included. Twenty-three (74.2%) studies used BOLD MRI to evaluate the CVR, 4 (12.9%) studies used ASL MRI and 4 (12.9%) studies used both BOLD and ASL MRI. Thirteen studies (3 significant) found a lower BOLD CVR, 2 studies found a similar CVR and 3 studies found a higher CVR in the ipsilateral compared to the contralateral hemisphere. Nine (5 significant) out of 10 studies found a lower BOLD CVR in the ipsilateral hemispheres of patients compared to controls. Six studies (2 significant) found a lower ASL CVR in the ipsilateral compared to the contralateral hemispheres. Three out of 5 studies found a significant lower ASL CVR in the ipsilateral hemispheres of patients compared to controls. Key Messages: This review brings support for a reduced BOLD and ASL CVR in the ipsilateral hemisphere of patients with cerebrovascular disease. We suggest that future studies will be performed in a uniform way so reference values can be established and could be used to guide treatment decisions in patients with cerebrovascular disease.

scholarly journals Measuring Cerebrovascular Reactivity: The Dynamic Response to a Step Hypercapnic Stimulus

2015 ◽  
Vol 35 (11) ◽  
pp. 1746-1756 ◽  
Author(s):  
Julien Poublanc ◽  
Adrian P Crawley ◽  
Olivia Sobczyk ◽  
Gaspard Montandon ◽  
Kevin Sam ◽  
...  
Keyword(s):  
Vascular Reactivity ◽  
Blood Oxygen Level Dependent ◽  
Cerebrovascular Reactivity ◽  
Blood Oxygen ◽  
Resonance Imaging ◽  
Blood Oxygen Level ◽  
First Order ◽  
Speed Of Response ◽  
Magnetic Resonance Imaging Mri ◽  
Best Fit

We define cerebral vascular reactivity (CVR) as the ratio of the change in blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) signal (S) to an increase in blood partial pressure of CO2 (PCO2): % Δ S/Δ PCO2 mm Hg. Our aim was to further characterize CVR into dynamic and static components and then study 46 healthy subjects collated into a reference atlas and 20 patients with unilateral carotid artery stenosis. We applied an abrupt boxcar change in PCO2 and monitored S. We convolved the PCO2 with a set of first-order exponential functions whose time constant τ was increased in 2-second intervals between 2 and 100 seconds. The τ corresponding to the best fit between S and the convolved PCO2 was used to score the speed of response. Additionally, the slope of the regression between S and the convolved PCO2 represents the steady-state CVR (ssCVR). We found that both prolongations of τ and reductions in ssCVR (compared with the reference atlas) were associated with the reductions in CVR on the side of the lesion. τ and ssCVR are respectively the dynamic and static components of measured CVR.

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