Angiographic Characteristics of Lobulated Intracranial Aneurysms

Previous studies have indicated that lobulated aneurysms are more susceptible to rupture than are single-sac aneurysms. We aimed to determine the angiographic characteristics related to the lobulated shape of unruptured intracranial aneurysms (UIAs) and ruptured (RIAs) intracranial aneurysms.

This is a retrospective analysis of consecutive patients with UIAs (n = 143) and RIAs (n = 190) who underwent digital subtraction angiography at our institution between 2010 and 2017. Patient and aneurysm characteristics were compared between lobulated and regular single-sac aneurysms.

Patients with lobulated UIAs were significantly older than were patients with regular aneurysms (56.5 ± 10.7 years vs. 49.3 ± 13.0 years; P = 0.003). In the multivariate analysis, lobulated morphology was significantly related to bifurcation location (69.5% vs. 27.3%; odds ratio [OR], 3.0, 95% confidence interval [CI], 1.2-7.5; P = 0.019), aneurysm size (8.1 ± 3.2 mm vs. 4.9 ± 3.0 mm; OR, 5.4; 95% CI, 1.7-17.8; P = 0.005), and inflow angle (145 ± 27° vs. 114 ± 27°; OR, 2.8; 95% CI, 1.1-7.2; P = 0.031). Bifurcation location (P = 0.031) and larger aneurysm size (P < 0.001) were confirmed as independent characteristics for lobulation in the RIA group. Compared with regular aneurysms, lobulated UIAs were more often allocated to treatment (86.6% vs. 60.3%; P < 0.001) and treated by microsurgical clipping (39.4% vs. 16.4%; P = 0.002).

Bifurcation location, an increased aneurysm size, and a straighter aneurysm inflow angle are independently associated with lobulated aneurysms.