Decreased flow in ischemic stroke with coexisting intracranial artery stenosis and white matter hyperintensities

Background Stroke patients with coexisting intracranial artery stenosis (ICAS) and white matter lesions (WML) usually have a poor outcome. However, how WML affects stroke prognosis has not been determined. Objective To investigate the quantitative forward flow at the middle cerebral artery in ICAS patients with different degrees of WML using 4D flow. Design Single-center cross-sectional cohort study. Methods Ischemic stroke patients with symptomatic middle cerebral artery (MCA) atherosclerosis were included, and they were divided into 2 groups based on Fazekas scale on Flair image (mild group = Fazekas 0-2, and severe group = Fazekas >2), TOF-MRA and 4D flow were performed to quantify the stenosis degree and forward flow at the proximal of stenosis. The flow parameters were compared between different white matter hyperintensity (WMH) groups, as well as in different MCA stenosis groups, logistic regression was used to validate the association between forward flow and WMH. Results A total of 66 patients were included in this study (mean age 56 years old, 68.2% male). 77.3% of them presented with WMH (Fazekas 1-5). Comparison of flow index between mild and severe WMH groups found a significantly lower forward flow (2.34 ± 1.09 vs 3.04 ± 1.35), higher PI (0.75 ± 0.43 vs 0.66 ± 0.32), and RI (0.49 ± 0.19 vs 0.46 ± 0.15) at ipsilateral infarction MCA in the severe WMH group, all P-values <0.05. After adjusting for other covariates, forward mean flow at ipsilateral infarction MCA is still associated with severe WMH independently, OR = 0.537, 95% CI (0.294, 0.981), P = 0.043. Conclusion Intracranial artery stenosis patients with coexisting severe WMH suffer from significantly decreased flow, which could explain the poor clinical outcome in this population, and also provide some insight into recanalization therapy in the future.