ASL evaluation of cerebral microcirculation after coil embolization for aneurysmal subarachnoid hemorrhage: effects of clazosentan

To evaluate the effect of continuous intravenous clazosentan on cerebral microcirculation after coil embolization for aneurysmal subarachnoid hemorrhage (aSAH) using arterial spin labeling (ASL) MRI. This retrospective study included 50 patients with aSAH treated by coil embolization between January 2021 and December 2024. Fasudil hydrochloride was used before October 2022 and clazosentan thereafter. All patients received cilostazol 200 mg/day and rosuvastatin 5 mg/day for vasospasm prevention. ASL-MRI was performed on day 7 (±1). Cortical and medullary signal intensities were measured, and the cortico-medullary ratio (CMR) was calculated. Multivariate regression identified independent factors associated with ASL signal intensity, and reliability was assessed using intraclass correlation coefficients (ICC). The clazosentan group showed higher cortical intensity ( P = 0.02; d = 0.13) and CMR ( P < 0.01; d = 0.79), while medullary intensity did not differ ( P = 0.12). Clazosentan was independently associated with higher cortical intensity ( β = 0.28, P = 0.04) and CMR ( β = 0.36, P = 0.02). ICCs indicated excellent inter-rater reliability (cortical 0.98, medullary 0.96, CMR 0.74). Continuous clazosentan infusion was associated with increased cortical ASL signal intensity, suggesting enhanced cortical perfusion. ASL provides a reliable, noninvasive method for evaluating cerebral microcirculation in aSAH.