MRI-Based Differentiation of Tumor Deposits and Lymph Node Metastases in Rectal Cancer: A Systematic Review of Diagnostic Performance

<b>Background/Objectives</b>: Preoperative discrimination between tumor deposits (TDs) and lymph node metastases (LNMs) in rectal cancer on MRI is clinically critical but remains challenging. <b>Methods</b>: A systematic review following PRISMA guidelines was conducted, including studies using MRI to differentiate TDs from LNMs with histopathology as reference. Performance metrics such as AUC, sensitivity, and specificity were extracted. <b>Results</b>: Four retrospective studies (n = 344 patients) were included. Morphology-based MRI showed moderate diagnostic accuracy (AUC 0.72-0.76), whereas DCE-MRI and radiomics models demonstrated improved performance (AUC up to 0.86). Combined multiparametric approaches integrating DWI, DCE, and radiomics yielded the highest discriminative values. <b>Conclusions</b>: MRI-based multiparametric models improve discrimination between TDs and LNMs in rectal cancer. Integration of functional and morphologic features may enhance staging precision and guide therapy planning.