Radioclinical problems raised by megalodolichobasilar artery. 17 cases and a review of the literature.

Megalodolichobasilar artery (MDBA) is a vascular abnormality characterized by a regular increase in caliber and lengthening of the vertebrobasilar system (VBS), with varying degrees of displacement. Several physiopathological theories have been put forward. Clinically, MDBA may compress the cranial nerves and may be responsible for ischaemic accidents of the brain stem, hydrocephalus or mass syndrome. The radiological images may be misleading. The diagnosis of MDBA should be considered on the basis of CT findings, and its should be confirmed by vertebral arteriography at the slightest doubt.