多b值扩散加权成像诊断血吸虫肝纤维化的实验研究

The Experimental Study of Multi b Value Diffusion Weighted Imaging to Diagnose Liver Fibrosis of Schistosomiasis

目的探讨MR扩散加权成像(DWI)和肝纤维化血清学指标诊断血吸虫肝纤维化及鉴别肝纤维化分期的能力。方法采用经腹部尾蚴贴片法感染兔建立血吸虫肝纤维化模型,行MR常规扫描及多b值DWI检查(b=0、20、50、80、100、200、400、600、800、1000 s/mm^2),同时检测血清肝纤维化指标透明质酸酶(HA)、层粘连蛋白(LN)、Ⅲ型前胶原(PC-Ⅲ)、Ⅳ型胶原(Ⅳ-C)。按METAVIR评分系统进行病理学分期,实验组兔分为无肝纤维化期(S0组),轻中度肝纤维化期(S1~2组),重度肝纤维化期(S3~4组),比较不同分期、不同b值的表观扩散系数(ADC)和指数表观扩散系数(eADC)以及血清学指标的变化情况。结果随着b值的增大,肝实质的ADC值逐渐变小,eADC值逐渐增大;随着肝纤维化的进展,ADC、eADC值亦表现出同样的变化趋势(P<0.01);b=600 s/mm^2时,各组间两两比较均具有统计学差异(P<0.05);b=80 s/mm^2、600 s/mm^2时,ADC、eADC值对于鉴别肝纤维化分期≥S1、≥S3具有较高的敏感度和特异度。血清肝纤维化4项指标中,只有HA与不同b值的ADC值之间均存在相关性,具有统计学意义(P<0.01)。结论 DWI的ADC/eADC值可以有效鉴别肝纤维化的不同分期;血清HA对血吸虫肝纤维化的诊断具有一定价值。

Objective To investigate the ability of MR diffusion-weighted imaging(DWI)and liver fibrosis serological markers to diagnose schistosomiasis liver fibrosis and to identify liver fibrosis staging.Methods The model of schistosomiasis liver fibrosis was established by infecting rabbits with abdominal sacral patch.MR routine scan and multi-b value DWI were performed(b=0,20,50,80,100,200,400,600,800,1000 s/mm^2),simultaneous detection of four indicators of serum liver fibrosis(HA,LN,PC-Ⅲ,Ⅳ-C).Pathological staging was performed according to the METAVIR scoring system.Rabbits in the experimental group were divided into no liver fibrosis(S0 group),mild to moderate fibrosis(S1-2 group),and severe liver fibrosis(S3-S4 group).Apparent diffusion coefficient(ADC)and exponential apparent diffusion coefficient(EADC)of different stages and different b values,as well as changes in serological indicators were analysed.Results With the increase of b value,the ADC value of liver parenchyma gradually decreased,and the EADC value increased gradually,and with the progress of liver fibrosis,the values of ADC and EADC showed the same trend(P<0.01).When b=600 s/mm^2,the comparison between the two groups was statistically significant(P<0.05).When b=80 s/mm^2,600 s/mm^2,ADC and EADC have a higher sensitivity and specificity for the differentiation of liver fibrosis stage than S1,or greater than S3.In the four markers of hepatic fibrosis,only HA has a correlation with ADC values of different b values,which is statistically significant(P<0.01).Conclusion DWI ADC and EADC value can effectively identify different stages of hepatic fibrosis.HA has a certain value in the diagnosis of liver fibrosis of schistosomiasis.