3.0 T MRI表观扩散系数诊断中度肝纤维化价值的实验研究

目的探讨3.0 T MRI表观扩散系数（ADC）诊断中度肝纤维化的价值。方法采用猪血清腹腔注射复制肝纤维化大鼠模型。采用3.0 T MRI 行DWI检查，计算b值=800 s/mm2时ADC 值。DWI 检查后快速处死大鼠，行病理检查，对照组（12 只）、轻度肝纤维化组（S1期18 只）和中度肝纤维化组（S2、S3期共22 只）比较采用单因素方差分析及SNK 法多重比较。采用ROC 曲线分析ADC 值区分中度和轻度肝纤维化的效能。结果中度肝纤维化组大鼠肝脏ADC 值为（1.47±0.39）×10-3 mm2/s，轻度肝纤维化组大鼠肝脏ADC 值为（1.78±0.67）×10-3 mm2/s，两组比较，差异有统计学意义，对照组与轻度肝纤维化组大鼠肝脏ADC 值比较差异无统计学意义（p >0.05），与中度组比较差异有统计学意义（p <0.05）。ADC 值区分中度肝纤维化和轻度肝纤维化的ROC曲线下面积（AUC）为0.79，以ADC 值=1.68×10-3 mm2/s为界值时，诊断的敏感性和特异性分别为61%和100%。结论3.0 T MRI 功能弥散加权成像能反映早期肝纤维化微观改变，肝脏ADC值有助于中度肝纤维化的诊断。

Experimental study of apparent diffusion coefficient from 3.0 T MRI in identification of moderate liver fibrosis

Objective To evaluate the value of apparent diffusion coefficient (ADC) from 3.0 T MRI DWI in identifying moderate liver fibrosis. Methods Rat model of hepatic fibrosis was established by intraperitoneal injection of porcine serum. The ADC values of the three groups were calculated when b value was 800 s/mm2. The rats were sacrificed quickly after DWI examination and then pathological examination was performed. The results of the control group, the mild liver fibrosis group (18 rats in S1 stage) and the moderate liver fibrosis group (22 rats in S2 and S3 stages) were compared by analysis of one-way ANOVA and SNK multiple comparison. ROC curve was used to determine the efficiency of ADC values in distinguishing moderate liver fibrosis from mild liver fibrosis. Results The ADC values of moderate and mild liver fibrosis were (1.47 ±0.39)×10-3 mm2/s, (1.78 ±0.67)×10-3 mm2/s respectively, significant difference was found between them. There was significant difference in the ADC value between the control group and the moderate liver fibrosis group, but no significant difference between the control group and the mild liver fibrosis group. The AUC of ADC in differentiating moderate liver fibrosis from mild liver fibrosis was 0.79, with the sensitivity of 61% and the specificity of 100% at the cut-off of 1.68 ×10 -3 mm2/s.Conclusions 3.0 T MR DWI can reflect the microscopic changes of liver fibrosis in the early stage, the ADC value of the liver contributes to identification of moderate liver fibrosis.