Vessel Wall Imaging of Intracranial Aneurysms: Systematic Review and Meta-analysis.

Vessel wall imaging (VWI) is emerging as a novel imaging tool for the management and risk stratification of patients with intracranial saccular aneurysms. Our objective was to compare the rates of wall enhancement in unstable (ruptured, growing, or symptomatic) and stable aneurysms and assess the ability of VWI with high-resolution magnetic resonance imaging to distinguish between these 2 entities. This study was performed according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, and eligible studies were identified through a comprehensive literature review. A meta-analysis was conducted to examine the association between aneurysm wall enhancement and aneurysm instability with the use of a random effects model. The I statistic was used to assess for heterogeneity. Six studies comprising 505 saccular aneurysms were included. Aneurysms that showed vessel wall enhancement had statistically significant higher odds of being unstable (odds ratio [OR]: 20; 95% confidence interval [CI]: 6.4-62.1; I: 63.1%). The sensitivity, specificity, positive predictive value, and negative predictive value of VWI in identifying unstable aneurysms were 95.0% (90.4-97.8), 62.7% (57.1-67.9), 55.8% (52.2-59.4), and 96.2% (92.8-98.0), respectively. There is a statistically significant association between vessel wall enhancement and aneurysm instability. Importantly, the lack of wall enhancement is a strong predictor of aneurysm stability. VWI could potentially provide new insights in the management of intracranial aneurysms.