Detection of cerebral artery fenestrations by computed tomography angiography

Cerebral artery fenestrations (CAF) are rare congenital variations usually diagnosed by digital subtraction angiography (DSA). The aim of this study was to examine the frequency of occurrence of fenestrations in cerebral arteries and their coexistence with cerebral aneurysms in computed tomography angiography (CTA).

All reports of cerebral CTA (1140) performed in one institution from March 2005 to December 2007 were analysed. We found 40 patients with single fenestrations of the intracranial arteries. All 40 examinations were retrospectively reviewed for location of vascular malformations and presence of aneurysms or subarachnoid haemorrhage (SAH). Medical histories of those patients were then analysed for evidence of SAH and referral reasons for CTA.

Forty fenestrated arteries were found in CTA: 18 basilar arteries (45%), 16 anterior cerebral arteries (40%), 4 anterior communicating arteries (10%) and one middle cerebral artery (2.5%). Only one vertebral artery fenestration was found due to the technique of the examination. Six patients (15%) with fenestrated arteries had a total of 8 aneurysms, although only one aneurysm was ipsilateral to the fenestration. In 8 cases of SAH, two were with no evidence of vascular malformation. The coexistence of CAF and aneurysms in CTA amounted to 15% (6/40), but the incidence of ipsilateral aneurysm was only 2.5% (1/40) and it affected the anterior cerebral artery.

Basilar artery fenestration is the most frequent observed fenestration in CTA, followed by anterior cerebral artery and anterior communicating artery fenestrations. Coexistence of fenestration and aneurysm is uncommon in CTA examination.