Dolichoectasia of the Vertebrobasilar System

The Rt VA is measuring 6.2mm and left VA is hypoplastic, with non-visualized V4. Basilar artery measued maximum diameter of 6.9mm and is seen compressing the antero-lateral pons on the right side.


Other names for this disorder include dolichoectasia, megadolichoectasia, fusiform aneurysm of the vertebral and basilar arteries, and tortuous vertebrobasilar system.


The mean diameter of the normal basilar artery is 3.17 mm at the level of the pons, and the bifurcation is located in the interpeduncular cistern adjacent to the dorsum sellae or in the suprasellar cistern below the level of the floor of the third ventricle.The major criteria for diagnosis of VBDE are an arterial diameter of over 4.5 mm at any location along its course and deviation of any portion by over 10 mm from the shortest expected course.

The vertebrobasilar system can be considered elongated if the basilar artery lies lateral to the margin of the clivus or dorsum sellae, or if it bifurcates above the plane of the suprasellar cistern. Ectasia can be considered to be present if the basilar artery has a diameter greater than 4.5 mm.
(Ref - Smoker WR, Corbett JJ, Gentry LR, Keyes WD, Price MJ, Mc- Kusker S. High-resolution computed tomography of the basilar artery, 2: vertebrobasilar dolichoectasia: clinical-pathological correlation
and review. AJNR Am J Neuroradiol 1986;7:61–72)


While many patients are asymptomatic, these cases illustrate some of the diversity of symptoms associated with vertebrobasilar dolichoectasia. Patients may present with cranial nerve dysfunction, transient ischemic attacks, hydrocephalus, and subarachnoid hemorrhage, rarely midbrain infarct associated with vertebral artery dissection, an unusual complication of dolichoectasia.
Ref : Vertebrobasilar Dolichoectasia: Evaluation with CT Angiography
Pedro T. Vieco, Edward E. Maurin III, and Cordell E. Gross, AJNR 1997


NOTE: Dolichoectasia has been also described in Anterior Circulation.
Ref : http://www.ajnr.org/content/16/7/1548.full.pdf