The Diagnostic Value of Dual-energy CT Multi-parameters in Differentiating Colorectal Cancer from Inflammatory Thickening of the Colorectal Wall.

INTRODUCTION: To compare and analyse the differences in dual-energy CT multi-parametric features between Colorectal Cancer (CRC) and Inflammatory Bowel Disease (IBD)-related colorectal wall thickening, and to evaluate their clinical application value. MATERIALS AND METHODS: A retrospective analysis was conducted on 300 patients with localized colorectal wall thickening who underwent dual-energy CT scans at our hospital between 2018 and 2025. After exclusions, 260 patients were included and divided into CRC (n = 140) and IBD (n = 120) groups. Measured parameters included Iodine Concentration (IC), Normalized IC (NIC), Effective Atomic Number (Zeff), Normalized Zeff (N-Zeff), Dual-Energy Index (DEI), Normalized DEI (N-DEI), CT40keV, CT100keV, and slope λ. Univariate and multivariate logistic regression identified independent predictors and constructed a combined model. ROC curves evaluated diagnostic performance. RESULTS: Significant differences were observed between groups for multiple arterial and venous parameters (p < 0.05). ICAP, NICAP, CT40keVAP, ICVP, NICVP, CT40keVVP, and λVP were independent predictors. The combined model achieved the highest AUC (0.937), sensitivity (91.9%), and specificity (84.8%); NICVP was the best individual parameter (AUC = 0.823). DISCUSSION: Dual-energy CT offers advantages over conventional CT in radiation dose and diagnostic accuracy, especially when endoscopy is not feasible. Venous-phase parameters generally outperformed arterial-phase parameters; NICVP was the best single parameter, and the combined model was superior. CONCLUSION: DECT multi-parametric analysis demonstrates clinical value in differentiating CRC from IBD, offering a non-invasive alternative that may reduce unnecessary colonoscopies, particularly when endoscopy is unsuccessful or contraindicated.