Anatomical variations of the intracranial arteries and their association with intracranial aneurysms: Insights from digital subtraction angiographies

The purpose of this study was to identify the anatomical variants (AVs) in the intracranial arterial circulation of patients who underwent neuro-interventional procedures (NIPs) and to describe their relationship with intracranial aneurysms (IA). We performed a cross-sectional analysis of angiographic images from patients who underwent NIP at the Interventional Neuroradiology Department of the National Institute of Neurology and Neurosurgery in México between July 1, 2020, and January 1, 2022. After reviewing images from 150 NIPs, we found 144 AVs., yielding a prevalence of 81%. Of these, 49 AVs (34%) were located in the anterior circulation (AC) and 95 (66%) in the posterior circulation (PC); 23 NIPs (16%) showed AVs in both the AC and PC. The most frequent AVs were the fetal pattern of the posterior cerebral artery (19%) and hypoplasia of the A1 segment (12%). AVs were significantly more common in patients with neurovascular disorders than those without (80% vs 49%, <i>p</i> = .003) and in patients with IA compared to those without (68% vs 47%, <i>p</i> = .048). In the studied population, AVs were predominantly located in the PC and are significantly more frequent in patients with neurovascular disorders, particularly those with IA.