Fenestrations of intracranial arteries detected with 3D rotational angiography

Abstract

Background and purpose: Fenestrations of intracranial arteries are variants resulting from incomplete fusion of primitive vessels. An association with aneurysms is suggested in many studies. On conventional angiography, fenestrations are rarely visible. 3D rotational angiography (3DRA) provides improved visualization of cerebral vessels from any desired angle. We used 3DRA to assess the frequency and location of fenestrations of intracranial arteries and a possible relationship with aneurysms.

Materials and methods: In 208 patients with suspected intracranial aneurysms, 3DRA of 1, 2, or 3 cerebral vessels (in 143, 16, and 49 patients) was reviewed for the presence and location of fenestrations and aneurysms. When fenestrations were present in combination with aneurysms, we noted the relationship of the locations.

Results: In 59 of 208 patients, 61 fenestrations were detected (28%). Fenestrations were more frequent in the anterior than in the posterior circulation (23% versus 7%), and the most common location was the anterior communicating artery (AcomA) (43 of 61, 70%). The frequency of fenestrations in 185 patients with aneurysms was not different from the frequency in 23 patients without aneurysms. Of 220 aneurysms present in 208 patients, 10 aneurysms (4.5%) were located on a fenestration. Of 61 fenestrations, 51 (84%) were not associated with an aneurysm.

Conclusions: With 3DRA, fenestrations were found in 28% of patients. In our study, fenestrations occurred more often in the anterior than in the posterior circulation, and the most common location was the AcomA. A definite relationship between fenestrations and aneurysms cannot be concluded from our data.

Fig 1.

Classification of the relation of the location of the fenestration with the location of the aneurysm. A, Aneurysm is located on the fenestration in a patient with a vertebrobasilar junction aneurysm and a proximal basilar fenestration. B, Aneurysm is located adjacent to (but not on) a fenestration in a patient with an AcomA aneurysm and a fenestration of the AcomA. C, Aneurysm is located remote from a fenestration in a patient with a basilar tip aneurysm and a proximal basilar fenestration.

Fig 2.

Flow chart of 208 patients with 3DRA.

Fig 3.

Unusual locations of fenestrations of intracranial arteries. A, Fenestration of the supraclinoid internal carotid artery associated with an aneurysm. B, A very small fenestration on the proximal middle cerebral artery. C, A short-segment fenestration of the posterior cerebral artery.

Fig 4.

Examples of middle cerebral artery fenestrations (arrows). A, Fenestration at the bifurcation with an associated aneurysm. B, Small fenestration at the neck of an aneurysm in a patient with 2 middle cerebral artery aneurysms. C, A 10-mm segment fenestration in a distal middle cerebral artery (M3).