The frequency of intracranial arterial fenestrations: a study with 64-detector CT-angiography.

Fenestration is a vascular variation that begins with a common origin, then splits into two parallel luminal channels and rejoins distally. Potential association between anomalies of cerebral circulation and increased occurrence of aneurysm makes intracranial arterial fenestrations important. The planning of intracranial arterial interventions may be complicated if a fenestration occurs proximal to the site of intended treatment. This study is planned to determine the frequency of fenestrations on CT angiography and to search whether there is relationship between aneurysms and fenestrations. CT angiographies of 395 consecutive patients, performed by 64-detector CT, were retrospectively reviewed for aneurysms and fenestrations. Overall fenestration frequency, fenestration frequency in patients with and without aneurysm, and aneurysm frequency in patients with and without fenestration were searched. Demographic characteristics of patients were also compared. Overall fenestration frequency was 12.9%. Vertebrobasilar system (5.56%) and anterior communicating region (5.32%) were the two most frequent sites of fenestration. The rate of fenestrations was not significantly different between patients who had and did not have aneurysms. Mean age was significantly higher, and females were predominant in patients with aneurysms. However our results did not show significant difference in age and sex of patients with fenestrations. The frequency of fenestrations in this study is higher than in previously published radiological studies, suggesting that fenestrations are relatively common. There is no significant relationship between the frequency of aneurysms and fenestrations.