Fenestrations of cerebral arteries and their correlation with brain aneurysms

Mila Ćetković ^1* Jelena Boljanovoc ² Ema Bexheti ³ Filip Vitosevic ⁴ Damljan Bogićević ⁵ Sonja Milašinović ⁶ Sadi Bexheti ³ Dejan Ćetković ⁷ Aleksandra Dožić ⁷ Milan Milisavljević ^2,8

• ¹ Institute of Histology and Embryology “Aleksandar Dj. Kostic”, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
• ² Laboratory for Vascular Morphology, Institute of Anatomy, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
• ³ Institute of Anatomy, Faculty of Medical Science, State University of Tetova, Tetova, North Macedonia
• ⁴ Special Hospital for Cerebrovascular Diseases “Sent Sava”, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
• ⁵ Special Hospital for Cerebrovascular Diseases “Sent Sava”, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
• ⁶ Institute for Children's Disease, Clinical Centre of Montenegro, Podgorica, Montenegro
• ⁷ Institute of Anatomy, Faculty of Dental Medicine, University of Belgrade, Belgrade, Serbia
• ⁸ Academy of Medical Sciences, Serbian Medical Association, Belgrade, Serbia

Fenestration of intracranial artery is an anatomical remnant from embryonic development of vascular system. Cerebral aneurysm is a focal pathological dilatation of the arterial wall. The combination of an aneurysm at the place of fenestration is rare in cerebral circulation, but with possible clinical implications. The aim of this study was to identify the frequencies of the fenestrations and aneurysms, their locations, and their relationships. The vasculature of 35 adult brains was used for the micromorphological dissection and analysis under the stereoscopic microscope, after injecting into the arterial vessels a mixture of formaldehyde, melted gelatin, and solution of India ink. We analyzed another group of corrosion vascular casts of the brain arteries obtained from 15 brains injected with methyl-methacrylate. One fenestration of the M1 segment of middle cerebral artery was sectioned for the histological analysis. We also examined the CT angiograms of 1230 patients, analyzed data and compared with anatomical findings. The fenestrations in our group of 50 anatomical specimens were found in 12 (24%) brains on different cerebral arteries. The aneurisms were noted in 6 (12%) brains, always one per brain, in one case (2.00%) associated with the wall of fenestration. The CT angiograms of 1230 patients showed 26 (2.11%) arterial fenestrations in 26 patients, 28 (2.28%) aneurysms, and in one case (0.08%), the aneurysm arose from the fenestration. The existence of an aneurysm on the fenestration of a cerebral artery is a rare phenomenon, much less common than the separate fenestration or the formation of an aneurysm.