[The x-ray anatomical structure of the anterior portions of the circulus arteriosus (Willisi) cerebri in aneurysms of the anterior cerebral-anterior communicating arteries]

Abstract

The angiographic findings were analyzed in 136 patients with aneurysms of forebrain and anterior communicating arteries and 27 patients examined for brain extravascular abnormality. Depending on the magnitude of effects of one of the internal carotids on the blood supply anterior communicating and forebrain arteries, symmetric and asymmetric filling variants for the anterior portions of Willis' circle were identified. The symmetric variant was detected in 30% of cases and in 67% of controls, the asymmetric was revealed in 70 and 33%, respectively. One of the ICAs was prevalent in filling the anterior portions of Willis's circle in 70.3% of patients with aneurysms and in 90.6% of cases the diameter of its ipsilateral segment A1 was larger than of the segment contralateral to A1. Aneurysms were located in the trunk of the anterior communicating artery in 13% of cases and in the corner of the forebrain artery and the anterior communicating artery in 87% of cases. Most aneurysms were located on the side of the prevailing segment A1. The influence of a hemodynamic factor on the formation of aneurysms in the area of the anterior communicating and forebrain arteries.