Neuroimaging Predictors of Futile Recanalization in Posterior Circulation Stroke: A Systematic Review and Meta-Analysis

PURPOSE: This systematic review and meta-analysis aimed to synthesize evidence on baseline and procedural neuroimaging markers associated with futile recanalization in posterior circulation stroke. DATA SOURCES: A systematic search was conducted across PubMed, Scopus, Web of Science, and Embase from inception through April 2025. STUDY SELECTION: Studies evaluating neuroimaging predictors of futile recanalization in patients with posterior circulation stroke who achieved successful recanalization (mTICI ≥2b) after endovascular treatment were included. DATA ANALYSIS: Risk of bias was assessed using PROBAST. Random-effects meta-analysis was performed for imaging parameters reported in two or more studies. Heterogeneity was assessed using I² statistics, and leave-one-out sensitivity analyses were conducted. DATA SYNTHESIS: Twelve studies comprising 3,521 patients met the inclusion criteria. Meta-analysis of five studies demonstrated that higher PC-ASPECTS scores were significantly associated with reduced odds of futile recanalization (pooled OR = 0.72, 95% CI: 0.60-0.86; I² = 74.8%). The BATMAN collateral score showed a non-significant general direction toward lower futile recanalization with higher scores (OR = 0.81; 95% CI: 0.57–1.14; I² = 51.8%). Additional imaging predictors identified across studies included PMT score, PC-CS, PComA patency, CBF <35% volume, and cerebral circulation time. Perfusion metrics such as hypoperfusion intensity ratio and core volume did not independently predict futile recanalization. LIMITATIONS: The current study has several limitations. A small number of included studies (mostly retrospective with limited sample sizes), high heterogeneity (I² = 74.8% for PC-ASPECTS), varying definitions of functional outcome, differing covariates in multivariable models with possible residual confounding, and wide variation in study size/design. Furthermore, we were unable to perform reliable formal subgroup analyses, and publication-bias assessments due to only five eligible studies for PC-ASPECTS and two for BATMAN, necessitating reliance on qualitative assessment and leave-one-out sensitivity analyses while leaving publication bias and small-study effects unexcluded. CONCLUSION: PC-ASPECTS is a robust imaging predictor of futile recanalization in posterior circulation stroke. Location-based and collateral-based imaging parameters demonstrate greater prognostic value than volumetric thresholds in this territory. Integration of multiple imaging parameters into composite scores may enhance predictive accuracy and guide patient selection.