Cerebral arterial fenestration.

Fenestration or duplication of a cerebral vessel is a rare congenital variation which most commonly involves the vertebral artery and is usually of no clinical significance. Fenestrations may have associated aneurysms remote to the anomaly or involving the proximal bifurcation of the fenestration. They may also be associated with other vascular malformations e.g. arteriovenous malformations and venous angiomas. Four fenestrated cerebral vessels and their angiographic appearances are reported in this study.