Abstract TP371: Aneurysmal Wall Enhancement on Vessel-Wall MRI Predicts Intracranial Aneurysm Progression: A Systematic Review, Meta-Analysis and Meta-Regression

Background: Aneurysmal wall enhancement (AWE) on vessel-wall MRI has been proposed as an imaging biomarker of intracranial aneurysm instability. We performed a systematic review and meta-analysis to quantify the association between AWE and subsequent aneurysm progression (growth or symptomatic progression) and to explore study-level modifiers. Methods: A systematic literature search of PubMed, Embase, and CENTRAL was performed from inception through August 2025. Observational studies reporting AWE and subsequent aneurysm progression were eligible. Random-effects meta-analysis produced pooled relative risks (RRs) with 95% confidence intervals (CIs), I 2 for heterogeneity, and a 95% prediction interval. Pre-specified subgroup analysis compared progression definitions (growth vs symptomatic). Meta-regression assessed study-level covariates (diabetes prevalence, female proportion, smoking, dyslipidaemia, prior SAH, hypertension, multiple aneurysms). Protocol: not registered. Results: Sixteen studies comprising 2,293 aneurysms were included. Overall, AWE was associated with a higher risk of aneurysm progression: RR 3.57 (95% CI 2.43–5.23). Heterogeneity was substantial (I 2 = 72%); the 95% prediction interval was 0.93–13.62. By definition, pooled RRs were 3.29 (95% CI 2.24–4.84) for growth and 3.70 (95% CI 1.70–8.05) for symptomatic progression (test for subgroup difference p = 0.79). Meta-regression showed that higher study-level diabetes prevalence was associated with attenuation of the AWE progression effect (coef −2.4548; SE 1.2115; p = 0.0427) as was female proportion (coef −4.0855; SE 0.9867; p < 0.0001). Other covariates were non-significant. Conclusions: AWE is associated with a higher risk of aneurysm growth and symptomatic progression, but substantial heterogeneity and study-level attenuation by diabetes and female proportion temper generalizability. Prospective patient-level studies or meta-analysis using individual participant data (IPD meta-analysis) are needed to confirm these findings.