Fig. 3
Dual-layer spectral-detector CT images of a 59-year-old male with MSI-H gastric cancer. A 64-year-old male with poorly differentiated adenocarcinoma. a–c The conventional CT images (a), ID map (b), and Zeff map (c) in arterial phase, respectively. d–f The conventional CT images (d), ID map (e), and Zeff map (f) in venous phase, respectively. Irregular thickening of the gastric wall in the antrum and local masses with soft tissue density can be seen, exhibiting progressive enhancement. The red dashed line shows the freehand mode ROIs of the tumor. ID values, NID values, and Zeff values are indicated in the figures, respectively. g The coronal image of venous phase. The red arrow shows the thickened wall of the gastric lower body and antrum, without suspicion of enlarged lymph nodes. h The utilization of the nomogram to predict the risk of MSI-H. Corresponding score of each feature is seen on points scale. When point scores for all variables were added, total scores and corresponding probability of MSI-H were presented on total points and probability scales, respectively. Moreover, observation values are superimposed on plot and are shown as red circles or diamonds and solid or dashed droplines. CDLCT value of this patient was 1.21. After points for each predictor were added, total number of points was 102. Corresponding risk of MSI-H was 0.923. Histologic examination verified MSI-H status. AP arterial phase; ID iodine density; λHU the slope of the spectral curve; MSI-H microsatellite instability high; NID normalized iodine density; VP venous phase; Zeff effective atomic number