【摘要】 目的探讨单指数及拉伸指数模型扩散成像诊断肝纤维化大鼠模型病理分期的价值。材料与方法将40只成年雄性Sprague-Dawley(SD)大鼠采用随机数字表法分为对照组(n=8)和模型组(n=32)。模型组采用胆管结扎法建立肝纤维化模型,在术后4个时间点(7、14、21、28d)采用随机数字表法选取8只大鼠行扩散加权成像检查获得肝脏表观扩散系数(ADC)、分布扩散系数(DDC)和水分子扩散异质性指数(α)值。MRI扫描结束后进行病理分析,将肝纤维化分为F0~4期。比较不同病理分期组间ADC、DDC和α值的差异,评价ADC、DDC和α值与病理分期的相关性。结果对照组8只均无纤维化,均为F0期。模型组F1期8只、F2期9只、F3期9只、F4期6只。不同肝纤维化病理分期各组大鼠的ADC、DDC和α值差异均有统计学意义(P均<0.05)。纤维化肝脏(F1~F4期)的扩散参数均低于对照组(F0期),差异有统计学意义,且不同纤维化分级之间的参数差异均有统计学意义(P均<0.05)。纤维化分期与单指数及拉伸指数参数(ADC、DDC、α)均具有相关性(r=-0.734、-0.792、0.505,P均<0.05)。结论拉伸指数模型扩散成像能更好地反映组织在超高b值下的水扩散特性,可作为标准DWI单指数模型的补充手段。更多还原

【Abstract】 Purpose To explore the diagnostic value of monoexponential and stretched exponential model diffusion imaging in pathological staging in rat liver fibrosis model.Materials and Methods Forty adult male Sprague-Dawley(SD) rats were randomly assigned into control group(n=8) and model group(n=32) by randomized digital table.Liver fibrosis was induced by biliary duct ligation(BDL).Diffusion weighted imaging was performed at 4 time points(7,14,21,28 days after operation),apparent diffusion coefficient(ADC),distributed diffusion coefficient(DDC) and waterdiffusionheterogeneityindex(α) were obtained.Pathologic analysis was carried out after MRI,and liver fibrosis was classified into 5 stages(F0-F4).The differences inthe diffusion parameters(ADC,DDC and α) between different stages were analyzed using one-way analysis of variance,and the correlation between the diffusion parameters and pathological staging was evaluated.Results No fibrosis occurred in the control group,all at F0 stage(n=8).There were 8 rats at F1 stage,9 rats at F2 stage,9 rats at F3 stage,and 6 rats at F4 stage in the model group.There were significant differences in the diffusion parametersamong different stages(F0-F4)(P<0.05).All the diffusion parameters of fibrotic livers(F1-F4) were lower than those in the control group,with statistically significant differences(P<0.05).There were also significant differences in these parameters between different fibrosis grades(P<0.05).Fibrosis stage had correlations with ADC,DDC and α(with r-0.734,-0.792 and 0.505,P<0.05).Conclusion Stretched exponential model diffusion imaging can better reflect the water diffusion characteristics of tissue under ultra-high b value,which can be used as a supplement to the standard DWI monoexponential model.更多还原