Fenestrations of the anterior communicating artery: incidence on 3D angiography and relationship to aneurysms.

BACKGROUND AND PURPOSE Demonstration of fenestrations of the anterior communicating artery (AcomA) with conventional digital subtraction angiography is very uncommon. The purpose of this study was to assess the incidence of visible fenestrations of the AcomA on 3D rotational angiography (3DRA) and to evaluate the relationship between fenestrations of the AcomA and aneurysms of the AcomA. MATERIALS AND METHODS We systematically reviewed 305 datasets of 3DRA of the internal carotid artery in 305 patients with aneurysms of the anterior circulation on a dedicated workstation for the presence of fenestrations on the AcomA. RESULTS In 78 of 305 3DRAs, only the ipsilateral A2 segment was visible; thus, the AcomA could not be evaluated. Of the remaining 227 3DRAs, a fenestration of the AcomA was present in 12 (5.3%; 95% CI, 3.0%-9.1%). Of 12 fenestrations of the AcomA, 10 (83%) were associated with 1 or more aneurysms of the AcomA. Of 305 patients, 133 had an aneurysm on the AcomA, and in 127 of these, the AcomA was visible. Of 127 AcomA aneurysms with a visible AcomA, 10 were associated with fenestration, which accounted for an incidence of AcomA fenestrations with AcomA aneurysms of 7.9% (95% CI, 4.2%-14.0%). The proportion of fenestrations of the AcomA with aneurysms of the AcomA was 4.4% (10/227), and the proportion of AcomA fenestration with an aneurysm at another location was 0.9% (2/227). This difference was statistically significant (P = .040). Even in retrospect, 11 of 12 fenestrations were not visible on 2D DSA images. CONCLUSION In selected patients with aneurysms of the anterior circulation, fenestrations in the AcomA were found with 3DRA in 5.3% of datasets. Most fenestrations were associated with 1 or more aneurysms of the AcomA.