The value of restriction spectrum imaging in predicting lymph node metastases in rectal cancer: a comparative study with diffusion-weighted imaging and diffusion kurtosis imaging

Background To investigate the efficacy of three-compartment restriction spectrum imaging (RSI), diffusion kurtosis imaging (DKI), and diffusion-weighted imaging (DWI) in the assessment of lymph node metastases (LNM) in rectal cancer. Methods A total of 77 patients with rectal cancer who underwent pelvic MRI were enrolled. RSI-derived parameters (f 1 , f 2 , and f 3 ), DKI-derived parameters (D app and K app ), and the DWI-derived parameter (ADC) were calculated and compared using a Mann–Whitney U test or independent samples t -test. Logistic regression (LR) analysis was used to identify independent predictors of LNM status. Area under the receiver operating characteristic curve (AUC) and Delong analysis were performed to assess the diagnostic performance of each parameter. Results The LNM-positive group exhibited significantly higher f 1 and K app levels and significantly lower f 3 , D app , and ADC levels compared to the LNM-negative group ( p