Intracranial Aneurysm Wall Enhancement Associated with Aneurysm Rupture: A Systematic Review and Meta-analysis

Rationale and Objectives: Aneurysm wall enhancement (AWE) on magnetic resonance vessel wall imaging has been proposed as an imaging marker of aneurysm wall inflammation and instability. We performed a systematic review and meta-analysis to summarize the association between AWE and aneurysm rupture. Materials and Methods: We performed a comprehensive literature search of studies evaluating the association between AWE and aneurysm rupture. We abstracted the following study data: study design, patient demographics, aneurysm characteristics, MRI protocols, and AWE assessment. We performed meta-analysis using a random-effects model. Study heterogeneity was assessed by using the Cochrane Q and I-2 statistic, and publication bias was examined by using the Begg-Mazumdar test. Results: Five studies with 492 subjects met eligibility for systematic review. We found a significant positive overall association between AWE and aneurysm rupture, with an odds ratio (OR) of 34.26 (95% confidence interval [CI] 10.20-115.07, p < 0.001). No significant heterogeneity (Q=5.38, p=0.25; I-2=26%) or publication bias (p=1.000) was present. In the separate analysis of circumferential AWE and aneurysm rupture, we identified marked heterogeneity across studies (Q=21.23, p < 0.001; I-2=86%). Further subgroup analysis considering the effect of aneurysm size showed that the strength of association between circumferential AWE and aneurysm rupture was significant in small aneurysms (<7 mm), with an OR of 26.12 (95% CI 6.11-111.75, p < 0.001), but limited in large aneurysms (OR=0.56, 95% CI [0.21, 1.44], p=0.23). Conclusion: AWE on magnetic resonance vessel wall imaging is significantly and independently associated with aneurysm rupture and may become a promising imaging marker to predict aneurysm behavior and identify high-risk aneurysms.