Net water uptake as a predictive neuroimaging marker for acute ischemic stroke outcomes: a meta-analysis

Objective: To assess the role of net water uptake (NWU) in predicting outcomes in acute ischemic stroke (AIS) patients. Methods: A systematic review and meta-analysis were performed, adhering to established guidelines. The search covered PubMed, Scopus, Web of Science, and Embase databases until July 1, 2023. Eligible studies reporting quantitative ischemic lesion NWU in admission CT scans of AIS patients, stratified based on outcomes, were included. Data analysis was performed using R software version 4.2.1. Results: Incorporating 17 original studies with 2217 AIS patients, NWU was significantly higher in patients with poor outcomes compared to those with good outcomes (difference of medians: 5.06, 95% CI: 3.00–7.13, p < 0.001). Despite excluding one outlier study, considerable heterogeneity persisted among the included studies (I ² = 90.8%). The meta-regression and subgroup meta-analyses demonstrated significantly higher NWU in patients with poor functional outcome, as assessed by modified Rankin Scale (difference of medians: 3.83, 95% CI: 1.98–5.68, p < 0.001, I ² = 72.9%), malignant edema/infarct (difference of medians: 8.30, 95% CI: 4.01–12.58, p < 0.001, I ² = 95.6%), and intracranial hemorrhage (difference of medians: 5.43, 95% CI: 0.44–10.43, p = 0.03, I ² = 91.1%). Conclusion: NWU on admission CT scans shows promise as a predictive marker for outcomes in AIS patients. Prospective, multicenter trials with standardized, automated NWU measurement are crucial for robustly predicting diverse clinical outcomes. Clinical relevance statement: The potential of net water uptake as a biomarker for predicting outcomes in acute ischemic stroke patients holds significant promise. Further validation through additional research could lead to its integration into clinical practice, potentially improving the accuracy of clinical decision-making and allowing for the development of more precise patient care strategies. Key Points: • Net water uptake, a CT-based biomarker, quantifies early brain edema after acute ischemic stroke. • Net water uptake is significantly higher in poor outcome acute ischemic stroke patients. • Net water uptake on CT scans holds promise in predicting diverse acute ischemic stroke outcomes.