Publication: Prevalence and Patterns of Circle of Willis Variants in Civil Service Hospital: A Retrospective Cross-Sectional Study Using 3 Tesla Magnetic Resonance Angiography
Date
2025
Journal Title
Journal ISSN
Volume Title
Publisher
Nepal Medical Association
Abstract
Abstract
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.
Description
Subash Thapa
Department of Radiodiagnosis, Nepal Police Hospital, Mahrajgunj, Kathmandu, Nepal,
Rabindra Desar
Department of Radiodiagnosis, Civil Service Hospital, Minbhawan, Kathmandu, Nepal
Jorina Basnet
Department of Internal Medicine, KIST Medical College & Teaching Hospital, Lalitpur, Nepal
Sushmita Thapa
Department of Accident and Emergency, Birendra Hospital, Chhauni, Kathmandu, Nepal