Browsing by Author "Thapa, Subash"
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Publication Prevalence and Patterns of Circle of Willis Variants in Civil Service Hospital: A Retrospective Cross-Sectional Study Using 3 Tesla Magnetic Resonance Angiography(Nepal Medical Association, 2025) Thapa, Subash; Desar, Rabindra; Basnet, Jorina; Thapa, SushmitaAbstract Introduction: The Circle of Willis (CoW) is a crucial cerebral arterial network, and its anatomical variations may influence cerebrovascular health. This study aimed to determine the prevalence and patterns of CoW variants using 3 Tesla magnetic resonance angiography. Methods: This retrospective cross-sectional study was conducted at the Department of Radiology, of a tertiary care center, Nepal, from October 2022 to September 2024 following ethical approval (IRC- 16/2024). Inclusion required adequate 3T MRI imaging using a TOF MRA protocol. (TR 20 ms, TE 3.5 ms, flip angle 15°, slice thickness 0.5 mm). Patients with cerebrovascular disease, prior interventions, or contraindications were excluded. Circle of Willis morphology was analyzed for prevalence, variants, and age/gender correlations using SPSS and Excel. Results: The study included 384 participants of which 206 (53.65%) were male. The mean age was 59.20±16.30 years. A complete Circle of Willis (COW) was observed in 139 (36.19%), while 220 (57.39%) were incomplete. Anterior anomalies 126 (32.81%) primarily consisted of hypoplasia 95 (75.40%), right A1 dominance) and absence 24 (19.05%). Posterior variants 345 (89.84%) frequently involved hypoplasia 155 (44.93%) or absence 189 (54.78%) of the posterior communicating artery, with fetal PCA origin in 121 (31.51%). Conclusions: This study found common Circle of Willis variations, especially in older adults. Hypoplasia of the posterior communicating artery was the most frequent variation, with differences observed by gender.