基于能谱CT的脾脏相关参数与食管静脉曲张程度的研究

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

目的:探讨应用能谱CT获得的脾脏血流动力学参数无创评估肝硬化门静脉高压症患者食管静脉曲张(EV)程度的价值。方法:回顾性选取2018年1月至2019年3月期间的肝硬化并发EV的患者57例作为研究组,根据内镜显示的EV程度将其分为轻度(EV1)、中度(EV2)及重度(EV3)三组;选取同期肝脏CT正常的患者20例作为对照组。所有患者均以能谱CT GSI模式行上腹部增强CT扫描检查,测量门静脉期脾脏实质碘浓度(IC-S)、脾脏体积(V-S)、脾静脉直径(D-SV),计算得脾脏碘容量(IV-S):IV-S=IC-S×V-S。应用单因素方差分析比较四组间上述指标的差异,组内两两比较采用LSD法,方差不齐采用Welch检验及Tamhane’s T2法,对有统计学意义的指标进一步应用ROC曲线评价其对重度EV的诊断效能,所有指标均以P<0.05为有统计学意义。结果:V-S,D-SV,IV-S在四组间的差异均具有统计学意义(P<0.001),其中研究组各参数的值均大于对照组,研究组内EV程度越重,各参数值越大。两两比较结果显示,除对照组与EV1组间的D-SV、EV2与EV3组间的V-S以及EV1与EV2组间V-S,D-SV,IV-S外,其余各组间的各参数的差异均具有统计学意义(P<0.05)。IC-S在各组间的总体差异不具有统计学意义(P>0.05)。当V-S,D-SV,IV-S预测EV3的临界值分别为736.220 cm3、12.695 mm和1812.285 mg时,曲线下面积分别为0.775、0.757和0.850,诊断重度EV的敏感度分别为0.720、0.480和0.800,特异度为0.750、0.937和0.781。结论:应用能谱CT得到的反映脾脏血流动力学状况的参数V-S,D-SV,IV-S,可反映EV程度,无创预测重度EV,其中以IV-S为最佳指标。

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 EV1 and 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 cm3,12.695 mm,1812.285 mg,respectively to predict EV3,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.