Cerebral Aneurysms: Are They Associated with Anatomic Variations of Carotid and Main Cerebral Arteries?

OBJECTIVE: Vascular anatomic variations are very common in the population, but their coexistence with life-threating vascular malformations remains unclear. The objective of the study was to assess the correlation between the presence of anatomic variants of both carotid and main cerebral arteries and the occurrence of cerebral aneurysms.

METHODS: We analyzed examinations of 194 patients who underwent computed tomography angiography of the head and neck between September of 2016 and November of 2017. The assessed parameters were: the variation of the common carotid arteries origin, hypoplasia or duplication of any of the main cerebral arteries, carotid artery kinking, and the presence of cerebral aneurysms.

RESULTS: We found 5.7% of patients had a cerebral aneurysm. Hypoplasia of at least 1 main cerebral artery occurred in 34.5% of patients, with the most frequent being the vertebral artery (21.6%). Duplication of at least 1 main cerebral artery was detected in 2.6%. Cerebral aneurysms occurred more often together with hypoplasia (P = 0.041; OR = 3.175) or duplication (P < 0.001; OR = 18.500) of at least 1 main cerebral artery. In 7.2% of cases, the origin of common carotid arteries created a true bovine arch, and in 4.1% the so-called bovine arch. Patients with alternative variants of aortic arch branching were more likely to have cerebral aneurysms (P = 0.002; OR = 5.903). We found 27.3% of patients had internal carotid arteries affected by kinking. Carotid kinking did not predispose the patient to the formation of a cerebral aneurysm (P = 0.378).

CONCLUSIONS: There is an evident correspondence between the presence of vascular anatomic variants (abnormal origin of the carotid arteries, hypoplasia, or duplication of the main cerebral artery) and the occurrence of cerebral aneurysms.