Lack of Baseline Intracranial Aneurysm Wall Enhancement Predicts Future Stability: A Systematic Review and Meta-Analysis of Longitudinal Studies.

ABSTRACT

BACKGROUND: The utility of vessel wall MR imaging in identifying unstable intracranial aneurysms has been suggested but remains controversial. PURPOSE: Our aim was to provide further insight into the potential relationship between aneurysm wall enhancement on initial vessel wall imaging and aneurysm instability at follow-up. DATA SOURCES Our sources were PubMed, Scopus, the Web of Science, and the Cochrane Central Register of Controlled Trials. STUDY SELECTION We searched for English language studies that reported the presence of vessel wall enhancement of unruptured intracranial aneurysms on baseline vessel wall imaging studies with longitudinal follow-up of aneurysm status. DATA ANALYSIS: Aneurysms were grouped into "stable" and "unstable" groups at follow-up on the basis of growth, symptomatic manifestation, or rupture. The association of each group with aneurysm wall enhancement on initial vessel wall imaging was determined. DATA SYNTHESIS: Three studies constituting 407 aneurysms were included. Aneurysms with wall enhancement were at higher risk of being unstable at follow-up (risk ratio = 3.6; 95% confidence interval, 1.7-7.5). The sensitivity of aneurysm wall enhancement on vessel wall imaging was 74.3% (95% CI, 56.7%-87.5%), specificity was 58.3% (95% CI, 53.1%-63.4%), positive predictive value was 14.4% (95% CI, 11.8%-17.4%), negative predictive value was 96.0% (95% CI, 93.2%-97.7%), and the overall accuracy of the test was 59.7% (95% CI, 54.8%-64.5%). LIMITATIONS: Only 3 studies were identified for inclusion in this analysis. More longitudinal studies of vessel wall imaging and aneurysm progression are needed. CONCLUSIONS: The lack of wall enhancement may be a predictor of aneurysm stability. The utility of vessel wall imaging in detecting unstable aneurysms requires more data.