Correlation between P2-PCA volume flow rate and BOLD cerebrovascular reactivity in patients with symptomatic carotid artery occlusion

BACKGROUND AND PURPOSE: Identifying and assessing hemodynamic and flow status in patients with symptomatic internal carotid artery (ICA) occlusion is crucial for evaluating recurrent stroke risk. The aim of this study was to analyze the correlation between two quantitative imaging modalities: (1) blood oxygenation level–dependent (BOLD) cerebrovascular reactivity (CVR) and (2) quantitative magnetic resonance angiography (qMRA) with non-invasive optimal vessel analysis (NOVA), measuring volume flow rate (VFR). Comparing these modalities is relevant for assessing collateral circulation and hemodynamic impairment.

MATERIALS AND METHODS: In this retrospective analysis of prospectively collected data, 37 symptomatic patients with unilateral ICA occlusion, who underwent both, NOVA-qMRA and BOLD-CVR investigation, were included. The correlation analysis between NOVAqMRA-derived second segment of the posterior cerebral artery (PCA-P2) VFR and BOLD-CVR (hemispheric and MCA territory CVR) was done by using a linear mixed-effects model.

RESULTS: A moderate correlation was found between P2-VFR and BOLD-CVR values for the ipsilateral MCA territory (|r|=0.44, R²=0.2, p<0.001) and the ipsilateral hemisphere (|r| =0.39, R²=0.15, p<0.001), indicating that 20% of the variance in P2-VFR can be explained by the BOLD-CVR of the MCA territory and 15% by the BOLD-CVR of the affected hemisphere.

CONCLUSIONS: This correlation suggests that impaired BOLD-CVR is partly linked to an increased PCA-P2 volume flow rate, potentially indicating the activation of leptomeningeal collaterals in severe hemodynamic conditions. Both imaging techniques could aid clinicians in in creating personalized treatment strategies for patients with symptomatic ICA occlusion.

ABBREVIATIONS: ACA = anterior cerebral artery; BOLD = blood oxygenation-level dependent; CVR = cerebrovascular reactivity; M1 = first segment of the middle cerebral artery; MCA =middle cerebral artery; NOVA = non-invasive optimal vessel analysis; P2 = second segment of the posterior cerebral artery; PCA = posterior cerebral artery; PCOM= posterior communicating artery; VFR = volume flow rate