Morphological Differences between Single and Multiple Unruptured Aneurysms

Abstract

The natural history and risk of rupture in multiple unruptured aneurysms is not clearly known. Various Morphometric indices have been proposed to correlate with risk of rupture of intracranial aneurysms. The present study aims to characterize and compare the morphology of patients with unruptured single and multiple aneurysms and correlate the results with rupture risk reported in previous studies. All patients with unruptured single and multiple aneurysms who presented to the hospital from 2009 to 2012 and who had complete 3D digital subtraction angiographic studies were included in the study. Their angiograms were analyzed for aneurysm height, width, and neck width and parent artery diameter. Aspect ratio, bottleneck ratio, height to width ratio and size ratio (SR) of single and multiple aneurysms were compared. 30 patients with single aneurysms and 18 patients with multiple (38) aneurysms were included in the study. Multiple aneurysms had a significantly smaller height and size ratios when compared to single aneurysms. There was no difference in age, gender, history of smoking and hypertension, aneurysm width, neck width, parent artery diameter, aspect ratio, bottle neck ratio and height to width ratio in both the groups. Multiple aneurysms have a lower size ratio than single aneurysms which may translate to a lower rupture risk per aneurysm. However, when patients with multiple aneurysms are considered, the cumulative risk of rupture should be taken into consideration.