The rCBV ratio on perfusion-weighted imaging reveals the extent of blood flow on conventional angiography after acute ischemic stroke

Abstract

Objective: In this study, we evaluated the relationship between the rCBV (regional cerebral blood flow volume) ratio on perfusion-weighted imaging (PWI) and the extent of collateral flow on conventional angiography.

Methods: We recruited 98 patients with AIS (within 24h after ischemic events). All the patients were evaluated by MRI, including PWI and diffusion-weighted imaging (DWI), and underwent digital subtraction angiography (DSA) of the brain. We hypothesized that the rCBV ratio on PWI could reveal the extent of the blood flow and predict early neurological deterioration (END) within 7 days after AIS.

Results: The rCBV ratio on PWI was significantly correlated with its extent on DSA (p<0.01). During the observation period, 24 patients (24.5%) experienced END. The univariate analysis revealed that severe neurological deficit at admission (p<0.01), the volume of the ischemic lesion on DWI (p<0.01), poor blood flow on DSA (p<0.01), the presence of DPM (p=0.05) and a low rCBV ratio on PWI (p<0.01) were related to END occurrence. The multivariate analysis showed that the presence of a low rCBV ratio on PWI was independently significant as a correlate of END (OR, 5.64; 95% CI, 1.68-18.90; p<0.01).

Conclusion: This study shows that the rCBV ratio on PWI may be a useful tool to reveal the status of blood flow after AIS. Moreover, the extent of collateral flow may be an important parameter that subtly influences the fate of DPM in AIS.

Keywords: Collateral flow; Magnetic resonance imaging; Perfusion; Stroke.