Basilar artery fenestration detected with CT angiography.

OBJECTIVES

To analyse the characteristics of basilar artery (BA) fenestrations and their coexistence with aneurysms and other anomalies in a massive cases by computed tomographic angiography (CTA).

METHODS

A total of 5,657 sequential cerebral CTA images performed from January 2006 to February 2012 were reviewed. CTA images were obtained from the raw datasets by using volume rendering and maximal intensity projection reconstruction.

RESULTS

One hundred and thirty-two (2.33 %) BA fenestrations were detected with CTA, and most common at the proximal segment (n = 124). BA fenestration-associated aneurysms were found in 34 cases and 7 located at the posterior circulation, and the frequency of posterior circulation aneurysms was significantly different in patients with and without BA fenestrations (P = 0.025). Other associated anomalies included arteriovenous malformation (n = 7) and moyamoya disease (n = 6). BA fenestrations were classified into Type I (74 cases), Type II (15 cases), Type III (41 cases) and Type IV (2 cases). A significant difference was observed between Types II + III associated with convex-lens-like and slit-like fenestrations (P = 0.008).

CONCLUSIONS

BA fenestrations were found in 2.33 % with CTA. They were significantly more often associated with posterior circulation aneurysms than those without BA fenestration. The anterior inferior cerebral artery (AICA) tends to originate more often from convex-lens-like fenestration than slit-like.

KEY POINTS: • Basilar artery fenestrations were found in 2.33 % of patients undergoing CT angiography. • Fenestrations were seen more often in the lower third with slit-like configurations. • No obvious relationship exists between basilar artery fenestration and aneurysm formation. • Basilar artery fenestrations perhaps predispose a patient to posterior circulation aneurysm formation. • The AICA tends to originate more often from convex-lens-like than slit-like fenestrations.