بررسی فراوانی واریاسیون ها و پاتولوژی های حلقه ویلیس با استفاده Magnetic Resonance Angiogram مغزی بدون تزریق ماده حاجب

Background and purpose: The complexity of anatomical variation of Willis circle (CW) has made it susceptible to variation. The goal of this study was to determine the prevalence of the CW variations using magnetic resonance angiography (MRA) without contrast agent in patients attending Sari Imam Khomeini Hospital. Materials and methods: In a cross-sectional study, 200 subjects referring for MRA were analyzed. Variables included hypoplasia, agenesis, stenosis, aneurysm, dolichoectasia, fenestration and duplication. Logistic regression model was applied to estimate the association between variation states in CW and other variables. Results: The most common variation was hypoplasia in left and right posterior communicating arteries (n= 118 (59.3%) and n= 107 (54%), respectively). Stenosis and dolichoectasia were more prevalent in anterior cerebral artery and basilar artery, respectively. Among the participants 90 (45%) were diagnosed with stenosis and 31 (15.5%) were reported to have dolichoectasia. Conclusion: Typical circles were seen only in 28 (14%) individuals and the rest had other variations. Therefore, MRA could be beneficial for diagnosis, treatment and prognosis.