Study of the Association between Spleen-related Parameters and the Degree of Esophageal Varices Using Dual Energy CT

Objective: To noninvasivly evaluate the degree of esophageal varices (EV) in cirrhotic patients with portal hypertension by the splenic hemodynamic parameters usingdual energy CT. Materials and Methods: Fifty-seven patients with EV in cirrhotic patients from January 2018 to March 2019 were retrospectively selected as the study group. The patients were divided into three groups according to the degree of EV confirmed by esophago gastroduo denoscopy (EGD): mild (EV₁), moderate (EV₂) and severe (EV₃). Twenty patients with normal liver CT manifestation were selected as the control group. All the patients underwent abdomen contrast-enhanced CT scan using gemstone spectral imaging mode by Discovery HD750. Iodine content of spleen (IC-S), volume of spleen (V-S) and diameters of splenic vein (D-SV) were measured on portal venous phase images. Iodine volume of spleen (IV-S) were calculated using the following fomula: IV-S=IC-S×V-S. ANOVA was used to compare the differences of the above parameters among four groups. Pairwise comparison within the group was conducted by LSD method, Welch test and Tamhane's T2 method were used for Unequal Variance. The ROC curve was used to analyze the diagnostic efficiency of the significant parameters. P<0.05 was considered statistically significant. Results: The differences of V-S, D-SV and IV-S among the four groups were statistically significant. Among them, the values of the control group were the minimum. The heavier the EV degree of the study group were, the greater the V-S, D-SV and IV-S were (P<0.001). Except for D-SV between the control group and EV₁ group, V-S between EV₂ and EV₃ group, and V-S, D-SV and IV-S between EV₁and EV₂ groups, the differences of above three parameters among the other groups were all statistically significant (P<0.05). The difference of IC-S among the four groups was not statistically significant (P>0.05). When the cut-off value of V-S, D-SV, IV-S was 736.220 cm³, 12.695mm, 1812.285mg, respectively to predict EV_3,the area under ROC curve was 0.775, 0.757, 0.850, and the sensitivity and specificity was 0.720, 0.480, 0.800 and 0.750, 0.937, 0.781, respectively. Conclusion: The parameters V-S, D-SV and IV-S, obtained by dual energy CT, could be used to evaluate the severity of EV and predict severe EV noninvasively, of which IV-S is the best indicator.