BACKGROUND: The management of small unruptured intracranial aneurysms is still controversial. Given the distinctive natural history of aneurysm at different locations, location-specific analysis might be a reasonable approach. This study aimed to investigate morphological discriminators for rupture status by focusing on only posterior communicating artery (PcomA) aneurysms smaller than 7 mm.
METHODS: In 108 small PcomA aneurysms (68 ruptured, 40 unruptured), clinical and morphological characteristics were compared between the ruptured and unruptured groups. Multivariate logistic regression analysis was performed to determine the independent predictors for the rupture status of small PcomA aneurysms.
RESULTS: None of the clinical characteristics were significantly different between the ruptured and unruptured group (P>0.05). The ruptured group revealed a significantly larger size (P=0.009), aspect ratio (P=0.009), size ratio (P=0.002), dome-to-neck ratio (P=0.002), inflow angle (P<0.001) and proportion of bleb formation (P=0.039). Bottleneck factor (P=0.154), diameter of PcomA (P=0.302) and fetal-type PcomA (P=0.832) showed no significance. With multivariate analyses, size ratio (P=0.012) and inflow angle (P=0.001) were shown to be independently associated with the rupture status of small PcomA aneurysms.
CONCLUSIONS: Morphological characteristics were closely related with the rupture status of small PcomA aneurysms. Size ratio and inflow angle were independent risk factors for rupture and might be useful in clinical risk stratification of small PcomA aneurysms.