Reduced CMRO₂ and cerebrovascular reserve in patients with severe intracranial arterial stenosis: A combined multiparametric qBOLD oxygenation and BOLD fMRI study

Abstract

Multiparametric quantitative blood oxygenation level dependent (mqBOLD) magnetic resonance Imaging (MRI) approach allows mapping tissular oxygen saturation (StO2 ) and cerebral metabolic rate of oxygen (CMRO2 ). To identify hemodynamic alteration related to severe intracranial arterial stenosis (SIAS), functional MRI of cerebrovascular reserve (CVR BOLD fMRI) to hypercapnia has been proposed. Diffusion imaging suggests chronic low grade ischemia in patients with impaired CVR. The aim of the present study was to evaluate how oxygen parameters (StO2 and CMRO2 ), assessed with mqBOLD approach, correlate with CVR in patients (n = 12) with SIAS and without arterial occlusion. The perfusion (dynamic susceptibility contrast), oxygenation, and CVR were compared. The MRI protocol conducted at 3T lasted approximately 1 h. Regions of interest measures on maps were delineated on segmented gray matter (GM) of middle cerebral artery territories. We have shown that decreased CVR is spatially associated with decreased CMRO2 in GM of patients with SIAS. Further, the degree of ipsilateral CVR reduction was well-correlated with the amplitude of the CMRO2 deficit. The altered CMRO2 suggests the presence of a moderate ischemia explained by both a decrease in perfusion and in CVR. CVR and mqBOLD method may be helpful in the selection of patients with SIAS to advocate for medical therapy or percutaneous transluminal angioplasty-stenting.

Acetazolamide-augmented dynamic BOLD (aczBOLD) imaging for assessing cerebrovascular reactivity in chronic steno-occlusive disease of the anterior circulation: An initial experience

“…The findings from previous studies on the relationship between CVR and baseline perfusion parameters are not consistent (Bouvier et al, 2015, Kawano et al, 2016), probably due to different imaging methods and correlation measures used. In the present study, we applied a mixed-effects model to account for the intra-subject repeated-measure dependency.…”

“…Cerebrovascular reactivity (CVR) has proved useful in predicting the risk of subsequent ischemic events among these patients (Bouvier et al, 2015, Gupta et al, 2012, Markus and Cullinane, 2001). The measurement of CVR is performed by quantifying the cerebrovascular response to vasodilatory stimuli, such as inhalation of air with increased CO 2 concentration (e.g.…”

“…Previous studies (Bouvier et al, 2015, Duffin et al, 2015, Mandell et al, 2008, Thomas et al, 2014) using BOLD for CVR measurement have largely utilized induced hypercapnia through inhalation of gas with increased CO 2 concentration; however, this approach requires specialized hardware for gas delivery and sampling, as well as good subject cooperation (Ringelstein et al, 1992), limiting its easy translation to clinical settings. In contrast, ACZ administration is safe and highly tolerated among patients from vast SPECT studies (Vagal et al, 2009), requiring only slow intravenous infusion achievable in the majority of subjects.…”

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

“…More importantly, within this study, no stroke-like symptoms outside the range of what should be expected were found [7] . One group reported anxiety evoked by hypercapnic breathing in 13% of their patients, and Bouvier et al [39] reported discomfort due to the face mask in 9% of the patients [40] .…”

BOLD fMRI of cerebrovascular reactivity in the middle cerebral artery territory: A 100 volunteers’ study

“…CVR impairment has been shown to be associated with hemodynamical IE downstream of the stenotic artery [15][16][17] and with low-grade ischemic injury [18,19]. Therefore, CVR imaging could be helpful to better select these patients and to justify the increased risk of PTAS adverse events, as well as to monitor post-therapeutic changes [20][21][22].…”