Circumferential Aneurysm Wall Enhancement Predicts Recanalization After Stent‐Assisted Coiling in Small Unruptured Intracranial Aneurysms

Background Circumferential aneurysm wall enhancement (CAWE) on high‐resolution vessel wall imaging (HR‐VWI) as a vessel wall inflammation marker is associated with unruptured intracranial aneurysms (UIAs) instability and recanalization after endovascular treatment. This study evaluates the association of CAWE with recanalization of small UIAs (< 10 mm) treated with stent‐assisted coiling (SAC) or coiling alone and aims to develop a prediction model for recanalization based on CAWE. Methods We analyzed patients with small saccular UIAs undergoing 3T HR‐VWI and treated with SAC or coiling alone between October 2018 and May 2024. A four‐grade scale assessed aneurysm wall enhancement (none, focal thick wall enhancement, thin CAWE, and thick CAWE). The aneurysm‐to‐pituitary stalk contrast ratio (CRstalk) quantified enhancement. We investigated the relationship between CAWE and recanalization and developed a recanalization prediction model. Results Sixty‐five patients with 69 UIAs were included; 11 aneurysms (15.9%) exhibited CAWE, and 10 had a CRstalk ≥ 0.5. Sixty aneurysms (87%) received SAC. Recanalization occurred in 14 of 69 aneurysms (20.3%), assessed by DSA follow‐up at 12.6 months. Multivariate analysis revealed that aneurysm size, CAWE, and CRstalk ≥ 0.5 predicted recanalization undergoing coiling with or without stent assistance. A scoring prediction model was created using aneurysm size, treatment, embolization occlusion, and CAWE, with scores ranging from 0 to 6, where scores ≥ 3 indicated high risk and a C‐statistic of 0.892 demonstrated excellent discrimination. Conclusions CAWE on HR‐VWI is a significant imaging marker for predicting recanalization in small UIAs undergoing SAC. The proposed recanalization risk scale needs validation in larger studies.