Comparative study of the arterial circle of Willis in individuals with or without cerebrovascular disorders

The study is devoted to the describe the anatomy of Willis circle in people with and without the cerebrovascular pathology. It was investigated in 243 angiograms of both males and females between the ages of 18 and 72. 120 patients had no signs of cerebrovascular pathology, and 123 patients had various types of disorders of the cerebral circulation. Results of the study have shown that only 32% of patients from the group without cerebrovascular disorders have the classical type of Willis circle. In 68% of patients, the atypical Willis circle was found, namely: 23% – hypoplasia of the anterior communicating artery, 21% – aplasia or hypoplasia of one of the posterior communicating arteries, 17% – combination of both anterior and one of the posterior communicating arteries aplasia, 4% – anterior and both posterior communicating arteries aplasia, 3% – parietal contact of both anterior cerebral arteries. Patients with cerebrovascular pathology show the typical anatomy of the Willis circle only in 2%. Other ones have different type of variation: aplasia of one of the posterior communicans artery have been noted in 53%, aplasia of both posterior communicating arteries – in 26%, combined aplasia of both anterior and posterior communicating arteries have been met in 19% of cases. Based on the above, it can be assumed the atypical type of the Willis circle is a predisposing factor for the development of cerebrovascular disorders.