Dual-energy CT for predicting serosal invasion in gastric cancer and subtype analysis

Purpose To predict the serosal invasion of gastric cancer (GC) using dual-energy CT (DECT)-based parameters and analyze the diagnostic performance according to different subtypes. Methods The patients were divided into the T1-3 group and T4a group. The irregular region of interest (ROI) was manually delineated on the largest cross-section of the lesion. The ROI area, iodine concentration (IC), normalized iodine concentration (nIC), fat fraction, CT value mean, and standard deviation were measured in the late arterial (LAP) and venous phase (VP). The Mann-Whitney U test was used to assess differences between different T-stage groups and histopathological subtypes of GC. A model was established based on DECT parameters, and the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic performance. Results Preliminary analysis showed that there were significant differences in ROI area, IC, nIC and CT value mean in VP and ROI area in LAP between T1-3 and T4a GC (all p < 0.05). The AUC of the comprehensive model composed of ROI and nIC in VP was 0.805. For different subtypes, multiple DECT parameters of poorly cohesive carcinoma (PCC) showed significant differences. Conclusion ROI area in LAP and VP, IC, nIC, and CT value mean in VP have significant differences in distinguishing between T1-3 and T4a GC. Iodine-related parameters in VP differed significantly between T1-3 and T4a in PCCs, rather than TACs. Considering the heterogeneity of different WHO subtypes, DECT iodine-related parameters in VP are more predictive of the serosal invasion status of GC compared to LAP. [GRAPHICS] .