Relationship between variations of circle of willis and multiple intracerebral aneurysms

Non-traumatic subarachnoid hemorrhage is a serious vascular event with high mortality. Most of these are caused by ruptured cerebral aneurysms. Digital subtraction angiography is considered the gold standard for diagnosis of these aneurysms, though CT angiography (CTA) is also known to have high sensitivity and specificity. Hemodynamic stress hypothesis is accepted by many researchers as an explanation of aneurysm development. The relationship between aneurysm development and variations of intracranial circulation that are thought to change the hemodynamics has been the subject of much research. In this study, patients who had a cerebral CTA at Akdeniz University Hospital Department of Radiology between January 2013 and September 2019 have been assessed, and after excluding appropriate patients, 1205 patients (262 cases with aneurysms and 943 control cases without) have been included. Images have been evaluated for twenty-one variations of circle of Willis and the association of these with multiple aneurysms. In all cases, there was a significant relationship between multiple aneurysms and variations such as Anterior cerebral artery (ACA) A1 segment aplasia, posterior cerebral artery (PCA) P1 segment hypoplasia, PCA P2 segment hypoplasia, fetal PCA, true fetal PCA, PCA-SCA common trunk, posterior communicating artery (PCoA) infindibulum. When only cases with aneurysms were considered, PCA P1 segment hypoplasia, fetal PCA, PCoA infindibulum and duplication variations had significant association with multiple aneurysms. We believe, when these variations are encountered on CTA images, keeping in mind the possibility of more than one aneurysm will increase the recognition of multiple aneurysms and thus improve patient care.