ANATOMICAL VARIATIONS AND DIMENSIONS OF ARTERIES IN THE POSTERIOR PART OF THE CIRCLE OF WILLIS

Abstract

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Background. The circle of Willis (COW) as an anastomotic polygon at the base of the brain, forms an important collateral network to maintain cerebral blood perfusion. Most of the variations have been reported on posterior cerebral and posterior communicating arteries. Aim. The aim of this study was to investigate different anatomic variations and dimensions of posterior part of the COW and their prevalence. Material and Methods. This is an observative descriptive study performed at the University Clinical Center, Clinic of Radiology. A randomized sample of 513 angiographic examinations in adult patients of both sexes without clinical manifestations for cerebrovascular disease who were instructed to exploration is included. Results and Discussion. The complete anterior part of COW is common with 77.7% of the all subjects, while the posterior part had a complete structure in 27.6% of the cases. The prevalence of unilateral FTPcomA was 14.7% and bilateral FTPcomA was found in 12.9%, while hypoplasia or absence of both PCoA in 45.8%. All dimensions of the arteries are larger in male than female, except the diameter of PCoA that is larger in female (p<0.05). Significant differences were found in diameters of arteries between the younger and the older age groups. Conclusions. Similar to other studies, most variations are related to the posterior part of the circle of Willis. Thus, knowledge of the variations, diameter and the length of the arteries of the circle of Willis has a great importance in interventional radiology for various endovascular interventions as well as during anatomy lessons.