Influence of the gender on cerebral vascular diameters observed during the magnetic resonance angiographic examination of Willis circle

Abstract

The present study evaluated the calibers and anatomic configurations based on the Magnetic Resonance analysis (MRA), assaying the cerebral vascular territories and sex-linked variations. A randomized sample of 30 angiographic examinations in adult patients of both sexes was obtained and components of the circle of Willis were identified. Branch diameters were measured on a transversal cut 5mm from the vessel origin in a typical angiographic frontal incidence. For the comparative statistical analysis, tests were divided in the groups considering the patients' sex and age. The classical Circle of Willis configuration was oberved in only 15 samples (50%). Greater calibers were observed in the arteries of the posterior circulation and multiple linear regression analysis established that the caliber of the posterior circulation was influenced by an independent variable related to the gender. Additional variations included unilateral and bilateral fetal and hypoplasic Posterior communicating arteries. In the anterior cerebral artery (ACA), the presence of an accessory developed ACA, an ACA giving branches to the distal portion of the two hemispheres and a third median ACA the variants were observed. Gender influenced the variations on internal diameters of posterior circulation vessels, with larger measurements in men.