Mediation of the relationship between cerebral blood flow and functional outcomes by quantification of perforator collateral capacity in patients with minor stroke and large vessel occlusion.

PURPOSE: Recognition of lenticulostriate arteries (LSAs) may reflect the presence of beneficial local collaterals. This study determined whether the morphological characteristics of LSAs were associated with clinical outcomes in individuals with intracranial atherosclerosis-related large vessel occlusion (ICAS-LVO) and minor stroke who underwent endovascular treatment and examined the potential hemodynamic relevance of these features. MATERIALS AND METHODS: This retrospective observational study included consecutive individuals with ICAS-LVO and minor stroke who underwent successful endovascular treatment between June 2020 and March 2022. LSA morphology was assessed on preinterventional high-resolution magnetic resonance imaging (HR-MRI) and classified as relatively good (LSA-sign+) or reduced (LSA-sign-). Cerebral blood flow in the LSA territory was quantified using arterial spin labeling. Associations between LSA characteristics, cerebral blood flow, and clinical outcomes were evaluated using multivariable logistic regression and Spearman correlation analyses, adjusted for potential confounders. RESULTS: Of 52 individuals included (median age, 59 years; 40 men), 24 (46.2%) had LSA-sign+. Multivariable analysis revealed that longer total LSA length was independently associated with higher odds of favorable outcome at 90 days (modified Rankin Scale score ≤2; OR = 1.14; 95% CI, 1.02-1.27; p = 0.02). Model performance improved with inclusion of the LSA feature. Mediation analysis demonstrated that the association between LSA characteristics and favorable outcome was mediated by cerebral blood flow (indirect effect = 0.16; 95% CI, 0.03-21.40). CONCLUSION: Total LSA length on preinterventional HR-MRI was an independent predictor of favorable outcomes after endovascular treatment. These findings provide new insight that may support clinical decision-making in ICAS-LVO and minor stroke.