目的：评价MR扩散加权成像（DWI）对肝纤维化的诊断效能，探讨表观扩散系数（ADC）与肝纤维化血清学指标之间的相关性。方法：CCl4皮下注射建立大鼠肝纤维化模型（38只）和对照组（10只）进行MR常规和DWI扫描，按肝纤维化病理分期进行分组，b取333、666和1000s/mm2时，比较各组DWI图像的信号强度（SI）和ADC值的变化。检测肝纤维化大鼠血清HA、PC Ⅲ、C-Ⅳ和LN变化，与肝纤维化分期和ADC值进行相关性分析。结果：肝纤维化病理分级：S0（n=3）、S1（n=5）、S2（n=9）、S3（n=13）、S4（n=8）。b取333、666和1000s/mm2时，随肝纤维化程度加重，SI依次升高，ADC值依次降低，差异有显著统计学意义（P<0.01）。ADC值与肝纤维化分期之间有很好的相关性，以b=1000s/mm2时相关关系最密切。b=333和666s/mm2时，根据SI值和ADC值可以将S0~S2期与S4期进行区分，S0期与S3、S4期进行区分。b=1000s/mm2时，可将S0~S2期与S4期进行区分。血清HA、PC Ⅲ、C-Ⅳ和LN随肝纤维化分期进展依次升高，ADC值与肝纤维化血清学指标之间存在不同程度的负相关（P<0.05）。结论：DWI可检测S3、S4期肝纤维化，但对判定S0～S2期轻度纤维化有局限性。ADC值与肝纤维化血液生化学各指标间存在很好的相关性，共同反映肝纤维化细胞外基质（ECM）异常增生和沉积的特征性病理改变。

Objective: To evaluate the diagnostic efficacy of diffusion-weighted MR imaging for liver fibrosis. To investigate the correlation between apparent diffusion coefficient(ADC) value and serum markers of liver fibrosis. Methods: Thirty-eight Wistar rats developed experimental model of liver fibrosis by carbon tetrachloride(CCl4) hypodermic injected and ten rats as control group were performed MR scans and MR-DWI. Grouping according to different stage of fibrosis, the results of DWI signal intensity(SI) and ADC were compared with different b values(333, 666 and 1000s/mm2). Blood samples were obtained after MR examination to observe serum markers of liver fibrosis including hyaluronic acid(HA), procollagen type Ⅲ(PC Ⅲ), type Ⅳ collagen(C-Ⅳ) and laminin(LN). The differences of results at various stages of liver fibrosis were compared. Analysis of relationships among serum markers and stage of liver fibrosis were performed. Results: Grouping according to different stage of fibrosis, S0(n=3), S1(n=5), S2(n=9), S3(n=13), S4(n=8). When b values equal to 333, 666 and 1000s/mm2 respectively, SI increased and ADC decreased gradually as the stage of fibrosis progressed(P<0.01). There was a good relationship between ADC and stage of fibrosis, especially when b value was 1000s/mm2. When b value equal to 333 and 666s/mm2, S0～S2 can be distinguished from S3 and S4 stage, and S3 can be distinguished from S4 stage according to SI and ADC values. Moreover b value equal to 1000s/mm2, S0～S2 can be distinguished from S4 stage. There was excellent negative correlation between ADC and serum indices(P<0.05). Conclusions: DWI would be a useful criterion for detecting liver fibrosis on S3 and S4 stage, but having limitation to detect early fibrosis(S0～S2 stage). Excellent correlation between ADC value and serum indices reflects the characteristic pathologic state of abnormal synthesis and deposition of extracellular matrix.