Abstract
BACKGROUND: Colorectal cancer (CRC) ranks among the leading causes of cancer-related mortality worldwide. Accurate detection of lymph node metastases plays a crucial role in determining disease stage and guiding treatment decisions. Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) and 18F-FDG PET/magnetic resonance imaging (MRI) are advanced imaging modalities widely used in clinical practice. The study aimed to compare the diagnostic accuracy of [ (18) F]FDG PET/CT and [ (18) F]FDG PET/MRI in detecting lymph node metastases in CRC patients. METHODS: A comprehensive literature search was conducted across PubMed, Embase, and Web of Science databases to identify relevant studies published up to February 2025. Inclusion criteria encompassed studies evaluating the diagnostic performance of [ (18) F]FDG PET/CT and [ (18) F]FDG PET/MRI for detecting lymph node metastases in CRC patients. Sensitivity and specificity were analyzed using the DerSimonian and Laird random-effects model, with results adjusted by the Freeman-Tukey double arcsine transformation. The quality of the included studies was appraised using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. RESULTS: This meta-analysis incorporated 24 studies with a cumulative total of 3,369 patients. The findings revealed that [ (18) F]FDG PET/CT exhibited significantly lower sensitivity (0.75 vs. 0.93, p = 0.0096) and a lower AUC value (0.81 vs. 0.96) compared with [ (18) F]FDG PET/MRI in detecting lymph node metastases among CRC patients. Both [ (18) F]FDG PET/CT and [ (18) F]FDG PET/MRI demonstrated similar specificity (0.77 vs. 0.88, p = 0.1892). Furthermore, the funnel plot asymmetry test indicated no significant publication bias across any of the outcomes (Egger's test: all p > 0.05). CONCLUSIONS: Our meta-analysis demonstrated that [ (18) F]FDG PET/MRI has higher sensitivity and comparable specificity to [ (18) F]FDG PET/CT in detecting lymph node metastases in CRC patients, suggesting its potential superiority for preoperative staging and postoperative surveillance. However, the limited number of direct head-to-head studies (only two) underscores the need for larger, prospective studies to validate these findings and assess their impact on clinical decision-making and patient outcomes.