Fenestrations accompanied by intracranial aneurysms assessed with magnetic resonance angiography

The aim of this study was to evaluate the anatomical changes and investigate the prevalence in intracranial aneurysm with fenestrations using magnetic resonance angiography (MRA).

Between June 2008 and October 2010, 4652 patients (aged 23-73 years) with suspected intracranial aneurysm or other cerebrovascular diseases underwent MRA examination. MRA was performed using a three-dimensional time-of-flight technique (3D-TOF) with volume rendering (VR) and maximum intensity projection reconstruction methods. The presence and location of fenestrations and aneurysms was reviewed. When fenestrations were present in combination with aneurysms, we noted the relationship of the locations. The classification of fenestration accompanied by intracranial aneurysm was divided into three types according to the anatomical relationship as follows: Type I, aneurysm adjacent to but not on a fenestration; Type II, aneurysm located on the fenestration; type III, aneurysm located at a position remote from a fenestration.

Among the 4652 patients examined, 409 patients were defined with 412 intracranial aneurysms, and the prevalence of aneurysms was 8.8%. One hundred and forty-one patients were identified with fenestrations; 24 of these patients were confirmed with intracranial aneurysms. Seven cases were classified as type I, three as type II and 14 as type III. The prevalence of intracranial aneurysm with fenestrations was 17.0%, with significant statistical difference compared with aneurysms unaccompanied with fenestrations (P=0.0064).

The anatomical relationship between fenestrations and intracranial aneurysms was visualized by MRA with VR, which displayed pathologies with sufficient clarity to enable diagnosis. Furthermore, the results of this study suggest that physicians should be alerted to the occurrence of intracranial aneurysm following the detection of fenestrations by MRA.