Circle of Willis variations and features in an American Midwestern cadaver population

Background

The Circle of Willis (CoW) is a critical cerebral arterial network. This study investigates CoW variants in a Midwestern U.S. cadaveric population.

Methods

The CoWs of 25 formalin-fixed human cadavers were evaluated with vessel measurements obtained through ImageJ software. Variations were classified per a previously published system with R Studio statistical analysis, including comparisons by sex and body mass index (BMI).

Results

A typical CoW configuration was identified in 2 of 25 specimens (8 %), with the remaining 92 % demonstrating anatomical variants. The most common variations were unilateral hypoplasia (38.3 %), bilateral hypoplasia (21.3 %), and duplications (12.8 %). Variations most commonly involved the posterior communicating artery (73.9 %; PComA; especially PComA hypoplasia), the anterior communicating artery (60.9 %; AComA), and the anterior cerebral artery (52.2 %). Rare anatomical variants included quadruplication of the A2 segment, fetal-type PComA, and AComA aplasia.

Males exhibited significantly greater vessel diameters and lengths across most segments, except for PComA diameter, which was larger in females (p < 0.05). Non-overweight body mass index (BMI < 25) correlated positively with the diameter of the extra triplicated A2, and increased BMI ( ≥ 25) showed a significant increase in the right A1 ACA diameter (p < 0.05). No statistically significant differences were observed in arterial lengths.

Conclusions

This study highlights the high prevalence of CoW anatomical variations in the Midwestern population, including several distinctive variants, adding to the literature. Significant differences based on sex and BMI were identified, suggesting potential implications for neurosurgical and vascular surgery considerations. Further research with additional cohorts is necessary to validate and expand upon these observations.