DTI对两种肝纤维化动物模型的定量研究

目的:探讨扩散张量成像(DTI)对肝纤维化的定量研究价值。方法:10只CCl4诱导肝纤维化SD大鼠模型及5只同期对照鼠在造模后20周行DTI检查(EPI序列,TR 1600ms,TE 68.1ms,6个方向,b=500s/mm2),完成检查后立即断头处死,4h内行离体肝组织DTI检查,18只血吸虫腹贴法诱导肝纤维化兔模型及10只同期对照兔在造模后8、10和12周分别行DTI扫描,完成扫描后将实验动物处死并取组织切片行HE、Masson染色,按肝纤维化分级分期标准将两种模型组的肝组织炎症活动及纤维化程度分为轻、中、重度三级。扫描图像经AW 4.2工作站处理,计算并分析肝纤维化鼠和对照鼠的在体、离体ADC值和FA值,肝纤维化兔各个时期的ADC值和FA值,并与纤维化程度行相关性分析,采用SSPS 13.0进行统计分析,显著水平取0.05。结果:①病理学证实两种模型纤维化程度分布相似,肝纤维化鼠炎症活动度高于肝纤维化兔(P<0.05);②模型组和对照组间在体、离体ADC值差异具有统计学意义,模型组ADC值、FA值在离体与在体间差异具有统计学意义,在体ADC值与纤维化程度呈负相关(r=-0.607,P=0.016);③肝纤维化兔ADC值在10和12周时,FA值在10周时模型组和对照组间差异具有统计学意义,不同时间点ADC值差异具有统计学意义(F=30.169,P<0.01),而FA值差异无统计学意义(F=1.147,P=0.326);ADC值与纤维化程度呈负相关(r=-0.765,P<0.01),而FA值与纤维化程度无相关性(r=0.189,P=0.356)。结论:两种肝纤维化模型纤维化程度与ADC值均有相关性,ADC值可成为定量评价肝纤维化指标。

Diffusion tensor imaging in quantification of two kinds of liver fibrosis animal model

Objective:To explore the feasibility of DTI in quantification of two kind of liver fibrosis animal models.Methods:Ten liver fibrosis Sprague Dawley(SD) rats induced by CCL4 for 20 weeks and five SD rats at the corresponding period were preformed with DTI in vivo and in vitro(within 4 hours after decollation).(EPI,TR 1600ms,TE 68.1ms,6 direction,B=500s/mm2).Eighteen liver fibrosis New Zealand rabbits induced by Schistosomiasis larvae and ten New Zealand rabbits at the corresponding period were performed with DTI at the 8th,10th and 12th week.All the animals were sacrificed after scan,received general observation,histology test,and the degree of fibrosis and inflammation was pathologically graded.The apparent diffusion coefficient(ADC) value and the fractional anisotropy(FA) value of liver were measured on rats(in vivo and in vitro) and rabbits(8th week,10th week,12th week) at the workstation AW4.2,and the results were correlated with the pathology results.Statistical analysis was using SPSS 13.0,and taking significant level of 0.05.Results:①Histology analysis confirmed that degree of the inflammation in the rat model group was statistically higher than that in the rabbit model group(P<0.05),but degree of liver fibrosis showed no statistically difference between the two model groups.②Variation of ADC value and FA value in liver fibrosis rats in vivo and in vitro were statistically significant different,and ADC values of liver fibrosis SD rats(in vivo) was negative correlated with grading scores of fibrosis(r=-0.607,P=0.016).③ADC values(in 10th and 12th week) and FA values of the liver fibrosis rabbits(in 10th week) were statistically significant different from the control groups.Variation of ADC values between time point were statistically significant different(F=30.169,P<0.01),though variation of FA values were not(F=1.147,P=0.326);ADC values of liver fibrosis rabbits were negative correlated with grading scores of fibrosis(r=-0.765,P<0.01),though FA values were not(r=0.189,P=0.356).Conclusion:There was significantly negative correlation between ADC values and pathological grading of fibrosis in the two kinds of liver fibrosis animal models.ADC value was a promising quantitive index to evaluate liver fibrosis.