Circle of Willis Anatomical Variations on CT Angiography: Prevalence and Clinical Associations in a Turkish Cohort

Background and Objectives: Anatomical variations in the Circle of Willis (CoW) may influence cerebral collateral pathways and the interpretation of vascular imaging. This study characterized their prevalence and clinical associations in a Turkish computed tomography angiography (CTA) cohort using complementary patient-level and component-level classifications. Materials and Methods: This retrospective, single-center study included 248 patients who underwent cranial CTA during 2024. Two radiologists independently assessed CoW anatomy, with disagreements resolved by consensus. Mutually exclusive patient-level configurations and non-exclusive arterial components were recorded. Associations with demographic and clinical characteristics were evaluated using logistic regression.