Association between Pretreatment Circumferential Wall Enhancement and Retreatment Rate in Endovascularly Treated Internal Carotid – Posterior Communicating Artery Aneurysms

Internal carotid-posterior communicating artery (IC-PC) aneurysms have a high recurrence rate after endovascular treatment. Pretreatment MRI vessel wall imaging (VWI) may predict recurrence through aneurysm wall enhancement (AWE) patterns; however, its role in IC-PC aneurysms remains unclear. This study investigated the association between pretreatment VWI findings and retreatment risk in patients with IC-PC aneurysms. This single-center retrospective cohort study included 173 patients with IC-PC aneurysms among 1145 intracranial aneurysms (IAs) treated endovascularly from 2016 to 2021. Patients without 1-year follow-up or pretreatment VWI were excluded. The baseline clinical, angiographic, and VWI characteristics were analyzed. AWE was classified into circumferential aneurysm wall enhancement (CAWE), focal enhancement, or negative. The primary outcome was the identification of risk factors for retreatment, as assessed using multivariate logistic regression. Retreatment was more frequent in IC-PC aneurysms than in all IAs (19% vs. 10%, p <0.001). Among IC-PC aneurysms, 141 patients required no retreatment (effective treatment group), and 32 required retreatment. Factors that were significantly different between the effective treatment and retreatment groups included initial presentation ( p =0.009), maximum aneurysm diameter ( p <0.001), neck width ( p <0.001), posterior communicating artery type ( p =0.019), and VWI enhancement pattern ( p <0.001). Multivariable analysis identified CAWE as the only independent predictor (odds ratio, 28.1; 95% confidence interval, 8.15–90.3; p <0.001). CAWE was observed in 72% of retreatment cases compared with 8.5% of effective treatment cases. Pretreatment CAWE on VWI is a strong independent predictor of retreatment in IC-PC aneurysms after endovascular treatment.