A High Burden of 10 or More Clinically Asymptomatic Lesions Suppresses Neurocognitive Improvement 6 Months After Endovascular Coiling for Unruptured Intracranial Aneurysms

Objective Endovascular coiling (EC) for unruptured intracranial aneurysms (UIAs) aims to safely prevent rupture while preserving cortical functions. However, newly developed silent embolic lesions are frequently captured on postprocedural diffusion-weighted imaging (DWI). This study evaluated how these subclinical lesions influence subsequent longitudinal neurocognitive trajectories using comprehensive psychometric batteries. Methods We retrospectively analyzed 26 consecutive patients who underwent EC for UIAs and completed detailed neurocognitive assessments both preoperatively and 6 months postoperatively. Neuroimaging was conducted using a 3-Tesla system, with DWI strictly obtained both on the immediate preprocedural day and on postoperative day 1 to count newly developed microlesions. Neuropsychological trajectories were evaluated via the WAIS-III and WMS-R batteries. Patients were stratified into the Low-Load (0 to 9 lesions, n  = 16) and the High-Load (10 or more lesions, n  = 10) groups. Results Cross-sectional inter-group comparisons revealed no statistically significant differences between the two cohorts. However, a critical disparity was unveiled during longitudinal intra-group analyses from baseline to 6 months. The Low-Load group demonstrated significant improvements across multiple cognitive domains, capturing score elevations in the PIQ ( p  = 0.0004), composite memory ( p  = 0.046), and average scores ( p  = 0.013). In contrast, these longitudinal improvements were abolished in the High-Load group (PIQ, p  = 0.477; memory, p  = 0.315; average, p  = 0.131). Conclusion While EC achieves excellent overall safety, a postprocedural DWI lesion count ≥ 10 is significantly associated with suboptimal neurocognitive recovery, counteracting the expected longitudinal practice effect. Neurointerventionalists should maintain strict embolic protection to ensure subclinical cognitive safety.