Diagnostic efficacy of [18F]FDG PET/CT and [18F]FDG PET/MRI in preoperative staging of locoregional urinary bladder cancer: a systematic review and Meta-Analysis

Abstract

Background: This systematic review and meta-analysis aims to evaluate the diagnostic utility of [18F]Fluorodeoxyglucose ([18F]FDG) PET/CT and [18F]FDG PET/MRI in preoperative locoregional staging of bladder cancer (BC). Methods: A comprehensive search of PubMed and Scopus databases was conducted up to February 26, 2025, to collect and analyze diagnostic accuracy parameters. Statistical analyses, including publication bias assessment, interstudy heterogeneity evaluation, and effect size adjustment, were performed using Stata software, with a significance threshold set at p < 0.05. Results: A total of 25 eligible studies were identified. Among these, three studies utilized [18F]FDG PET/MRI for primary tumor detection, yielding a pooled sensitivity of 90%. In contrast, five studies employing [18F]FDG PET/CT for the same purpose reported a pooled sensitivity of 69%. Notably, [18F]FDG PET/MRI demonstrated threefold greater effectiveness in primary tumor detection compared to [18F]FDG PET/CT based on results of indirect comparison of true positive odds ratio between the two modalities. For lymph node staging, 18 studies employed [18F]FDG PET/CT, with pooled sensitivity and specificity estimates of 50% and 91%, respectively. Significant interstudy heterogeneity was observed in lymph node staging, primarily attributed to variations in PET/CT protocols. Studies incorporating bladder priming strategies, dual-time-point imaging, and contrast-enhanced CT protocols achieved superior sensitivity and specificity compared to traditional PET/CT approaches. Conclusion: The findings highlight the compelling potential of [18F]FDG PET/MRI for primary tumor staging in BC. Further research is warranted to explore this innovative modality’s role in locoregional BC evaluation. Additionally, substantial heterogeneity in [18F]FDG PET/CT protocols underscores the need for standardization to improve sensitivity. Thus, Future studies should focus on addressing these limitations by adopting optimized PET/CT protocols.