Vascular geometry of vertebrobasilar tree with and without aneurysm.

AIM To examine a possible relationship between the variable vascular geometry of vertebrobasilar joint angle and basilar bifurcation angle as well as the diameters of these blood vessels. METHODS The study included 60 adult patients, of both sexes, who were divided into two groups. One group (30) consisted of patients without aneurysm of vertebrobasilar tree, and another group (30) of patients with aneurysm. The patients were examined using Magnetic Resonance Imaging (MRI) and Computed Tomography Angiography (CTA) of head and neck. RESULTS In the group without aneurysm of vertebrobasilar tree, in 14 (46.6%) patients diameters of the right and the left vertebral artery were approximately the same. The average value of the angle of junctions of vertebral arteries was 65.43°, and the average angle of basilar bifurcation was around 94.53°. In the group with aneurysm of vertebrobasilar tree, in 12 (40%) patients diameters of the right and the left vertebral artery were also approximately the same. The average angle of junction of vertebral arteries was 68.46º, and the average angle of basilar bifurcation was 121.93º. CONCLUSION Anatomic variations of the vertebrobasilar joint angle and basilar bifurcation angle, as well as the diameters of these blood vessels, are some of the factors in the increase of the incidence of aneurysm in this anatomic area.