Threshold-Independent Amide Proton Transfer-Weighted MRI in Post-Treatment Gliomas: A Systematic Review and Meta-Analysis of Effect Size and Diagnostic Accuracy

Post-treatment glioma surveillance often cannot reliably separate progressive disease (PD) from treatment-related effects (TRE) using conventional MRI alone. Amide proton transfer-weighted (APTw) MRI, a chemical exchange saturation transfer technique that reflects tissue protein content, has been investigated for this purpose; however, existing meta-analyses have quantified only cutoff-dependent diagnostic accuracy, and the magnitude of APTw signal separation has not been systematically synthesized. A systematic literature search was performed in PubMed and Web of Science (7 July 2026; no language restrictions). The same search strategy was applied to both databases. The search identified seven eligible studies. Five studies reporting continuous data (n = 218 patients) were pooled for the standardized mean difference (Hedges’ g) in APTw signal between PD and TRE. The pooled Hedges’ g was 1.54 (95% CI, 0.73–2.35; p = 0.006, Hartung–Knapp adjustment). Between-study heterogeneity was 63.9%, and the 95% prediction interval ranged from 0.04 to 3.04. Six studies provided diagnostic accuracy data, yielding pooled sensitivity, specificity, and HSROC AUC values of 0.88, 0.78, and 0.86, respectively. Case definitions varied across studies: four studies confirmed 19–40% of cases histopathologically, whereas three relied exclusively on radiologic follow-up. The limited number of available studies precluded subgroup analyses and molecular stratification. The small number of included studies and the high between-study heterogeneity (I2 = 63.9%) limit the generalizability of these results. All five studies reported higher APTw signal in PD than in TRE; however, the magnitude of this difference remains imprecisely estimated and requires confirmation in prospective, homogeneous cohorts.