肝纤维化MR弥散加权成像与病理的对照研究

摘要

目的 探讨肝纤维化时MR弥散加权成像(MR-DWI)中表观弥散系数(ADC)值的变化规律及其病理基础.方法 使用腹腔注射CCl4法建立兔肝纤维化模型并进行MR-DWI检查.弥散敏感梯度值b=600 s/mm~2.测量ADC值,比较不同肝纤维化分期时ADC值,变化规律,并与光镜及电镜下病理改变进行对照分析.结果 随肝纤维化分期进展,ADC值逐渐下降(P<0.05);病理学表现为肝内纤维基质数量增多、范围扩大,肝组织炎症反应逐渐加重.结论 随肝纤维化分期进展ADC值下降,可能为肝内纤维沉积增多及细胞内外水分子弥散异常限制水分子运动所致.%Objective To investigate the alteration of apparent diffusion coefficient (ADC) in diffusion-weighted MR imaging (MR-DWI) of liver fibrosis and its pathological basis in rabbits. Methods Five rabbits in the control group and 22 with experimental liver fibrosis induced by transperitoneal injection of carbon tetrachloride (CCl4) were examined with MR-DWI. Diffusion-weighted SE EPI sequence with a relatively high b factor (b=600 s/mm~2) was used to measure the ADC. The mean values of ADC were compared among the rabbits in different stages of liver fibrosis and analyzed in relation to the pathological findings. Results The mean ADC value decreased significantly with increased severity of liver fibrosis (P<0.05). Pathologically, the amount and extension of fibrotic matrix increased, and the hepatic necroinflammation worsened with the progression of the liver fibrosis. Conclusion The ADC value decreases with the progression of liver fibrosis possibly as the result of water diffusion limitation due to increased fibrous tissue in the liver and abnormal water diffusion within the intracellular and extracellular spaces.