Evaluation of normal variants of the circle of Willis using MRI-MR angiography

Abstract

Background: The Circle of Willis (CoW) is a critical arterial structure supplying blood to the brain. Variations in its configuration can influence cerebrovascular pathology and ischemic stroke risk. Magnetic Resonance Angiography (MRA) is a non-invasive imaging modality that provides detailed visualization of these variations.

Objective: To evaluate normal variants of the Circle of Willis using MRI-MR Angiography and assess their prevalence among different age groups and genders.

Materials and Methods: This hospital-based observational study was conducted at Vinayaka Mission's medical College and hospital,karaikal, over two years (November 2022–November 2024). A total of 50 patients referred for MRI Brain underwent 3D Time-of-Flight (TOF) MR Angiography. Variations in the anterior and posterior components of the CoW were analyzed using SYNGO VIA USER software. Statistical analysis was performed using SPSS version 20, with a p-value <0.05 considered statistically significant.

Results: Among the 50 participants, 56% were male and 44% were female, with a mean age of 47.26 (±18.48) years. The most common variation in the anterior circulation was Pattern A (82%), while the posterior circulation was predominantly Pattern K (54%). A complete CoW was observed in 52% of cases, whereas 44% had a partial configuration, and 4% exhibited an incomplete pattern. There was no significant association between CoW variations and age or gender (p > 0.05).

Conclusion: Normal variants of the Circle of Willis are prevalent, with a balanced configuration observed in most cases. MRA serves as an effective imaging modality for assessing these variations, aiding in the early identification of individuals at risk for cerebrovascular events.