全肝ADC直方图及T2WI肝脏信号强度指标在大鼠肝纤维化分期中的价值

The Value of Whole-liver ADC Histogram and TWI Liver Signal Intensity in Liver Fibrosis Stage in Rats

目的探讨全肝表观扩散系数(ADC)直方图参数和磁共振T2WI肝脏信号强度指标(SII)在大鼠肝纤维化分期中的应用价值。方法将44只大鼠分为四氯化碳诱导2~12周的肝纤维化组(n=37)和对照组(n=7)。利用专用软件(FireVoxel)对全肝ADC值进行直方图分析,计算ADC值的最小值、最大值、均值、中位数、众数、标准差、不均一性、偏度、峰度、熵、第10、25、50、75、90百分位参数;在脂肪抑制T2WI序列测量肝脏信号强度与右侧竖脊肌信号强度的比值,分析T2WI肝脏SII与肝纤维化分期之间的相关性及诊断价值。采用受试者工作特征(ROC)曲线分析其评估肝纤维化分期的诊断效能。结果最终纳入38只大鼠,分别有7、7、7、9、8只大鼠被诊断为F0~F4期。ADC值的直方图参数不均一性、偏度、峰度、熵、第75百分位数在不同肝纤维化阶段分期中有显著差异(P<0.05),其中,峰度是诊断不同肝纤维化分期阶段最有意义的参数,熵其次。对照组与肝纤维化组SII值差异有统计学意义(P<0.05),且Spearman分析示SII值与纤维化程度间r=-0.406,P=0.012,峰度与纤维化程度间r=0.511,P=0.040。ROC曲线示峰度鉴别各组纤维化分期诊断效能均较好。SII值诊断≥F1、≥F2、≥F3肝纤维化的曲线下面积(AUC)为0.906、0.863及0.755,敏感度为85.7%、99.4%及85.7%,特异度为90.3%、75.6%及70.7%。结论ADC直方图参数峰度在一定程度上可用于肝纤维化分期的诊断;SII值对正常及肝纤维化肝脏的诊断有一定的价值。

Objective To investigate the diagnostic value of whole-liver ADC histogram parameters and magnetic resonance T2WI liver signal intensity index(SII)in liver fibrosis stage of rats.Methods 44 rats were divided into carbon tetrachloride-induced fibrosis groups(n=37)and a control group(n=7).Histogram analysis of whole liver ADC using dedicated software(FireVoxel)and parameters including ADC minimum,maximum,mean,median,mode,standard deviation(SD),Inhomogeneity,skewness,kurtosis,entropy,10 th,25 th,50 th,75 th,90 th percentiles were calculated.The SII was calculated as the signal intensity ratio between the hepatic parenchyma and the right erector spinae muscles on the same section of FS T2WI MR images for all included cases.analyzeing the correlation,and staging value between the indexes of liver signal intensity on T2WI and the stages of liver fibrosis.Using receiver operating characteristics(ROC)analyses were further established to evaluate the potential diagnostic performance for differentiating liver fibrosis stages.Results A total of 38 rats were included,and 7,7,7,9,and 8 rats were diagnosed as F0-F4.Inhomogeneity,skewness,Kurtosis,entropy,and 75 th percentiles exhibited significant differences among the pathological fibrosis stages(P<0.05).Kurtosis was found to be the most meaningful parameter in the diagnosis of different stages of liver fibrosis,followed by entropy;There was significant differences in SII between the control group and the liver fibrosis group(P<0.05),and Spearman analysis showed that r=-0.406,P=0.012 between SII value and fibrosis degree,r=0.511,P=0.040 between kurtosis and fibrosis degree.The Kurtosis of ROC curve showed that identify the stages of fibrosis in each group were better than other parameters.The AUC of SII value in the diagnosis of liver fibrosis stage≥F1、≥F2、≥F3,AUC=0.906,0.863,0.755,sensitivity 85.7%,99.4%,85.7%,specificity 90.3%,75.6%,70.7%.Conclusion To some extent,the kurtosis of ADC histogram analysis can be used for the diagnosis of liver fibrosis stage;SII value is valuable for the diagnosis of normal liver and liver fibrosis.