3.0T MR弥散加权成像及张量成像评价肝纤维化的临床研究石喻

 目的 探讨MR弥散加权成像(DWI)及张量成像（DTI）对慢性病毒性肝炎患者的肝纤维化程度定量分析的能力。方法 应用3.0T MR对8名志愿者、40例慢性病毒性（乙型或丙型）肝炎患者进行DWI及DTI检查，弥散敏感度(b值)选择0，800 s/mm2，比照肝穿病理结果，计算表观弥散系数（ADC）及平均弥散率（MD），分析两种方法定量肝纤维化分期的能力。结果 受试者的肝脏ADC和MD分别为(1.26±0.12)×10-3 mm2/s和(1.39±0.14)×10-3 mm2/s，差异有统计学意义（Z=-5.775，P<0.01）。ADC、MD与纤维化分期呈显著负相关（r分别为-0.686，-0.481，P<0.01）；ADC可有效鉴别正常肝脏（S0期）与S2 、S3、S4期纤维化（P<0.05），肝硬化（S4期）与S1、S2、S3期纤维化（P值分别为 0.003，0.041，0.014）；MD能有效鉴别S4期与S0、S1期纤维化(P值分别为0.002，0.026），但不能鉴别比较其他各期纤维化(P >0.05）。ADC预测≥S2期、≥S3期及≥S4期纤维化的能力均优于MD（ROC曲线下面积，ADC分别为0.879、0.823、0.866；MD分别为0.796、0.743、0.725）。结论 DWI对肝纤维化分期的定量分析效果全面优于DTI，适合慢性病毒性肝炎患者的纤维化评价。

MR Diffusion Weighted Imaging and Diffusion Tensor Imaging for Quantification of Liver Fibrosis at 3.0T

Objective To evaluate MR diffusion weighted imaging(DWI)and diffusion tensor imaging(DTI)for quantifying liver fibrosis in patients with chronic viral hepatitis.Methods A total of 8 healthy volunteers and 40 patients with chronic HBV or HCV hepatitis who underwent liverbiopsy,and were enrolled in this study using a 3.0T MR unit at b values of 0,800 s/mm2.The apparent diffusion coefficient(ADC) and mean diffusion(MD) were measured in the liver parenchyma respectively and compared between patients stratified by fibrosis stage.Results The mean ADC values were significantly lower than the MD values in volunteers and patients(1.26±0.12×10-3 mm2/s,1.39±0.14×10-3 mm2/s;Z =-5.775,P < 0.01).ADC was negatively correlated with the staging of liver fibrosis,which was more accurate in staging than MD(r =-0.686,P < 0.01;r =-0.481,P < 0.01).There was no significant difference in liver MD among individual stages of fibrosis(except for S4 vs.S0,S1,P =0.002,0.026).There were significant differences in liver ADC between control livers and moderate to severe fibrosis(S0 vs.S2,S3,S4,P < 0.05),and between cirrhosis and mild to moderate fibrosis(S4 vs.S1,S2,S3,P =0.003,0.041,0.014).ROC analysis showed that ADC was superior to MD for the detection of fibrosis stage≥2,stage≥3 and stage≥4(area under the ROC curve,ADC:0.879,0.823,0.866;MD:0.796,0.743,0.725).Conclusion DWI can be used to predict the liver fibrosis of chronic viral hepatitis with acceptable sensitivity and specificity,and perform better than DTI at a 3.0T MR unit.