磁共振扩散加权成像在家兔肝纤维化分期的诊断价值

目的：探讨磁共振扩散加权成像(MR-DWI)在家兔肝纤维化(HF)分期中的价值。材料与方法将60只健康新西兰大白兔随机分为HF组(32只)、对照组(16只)和补充组(12只)。HF组和补充组兔经颈背部皮下注射50%的CCl4油溶液建立肝纤维化模型。在造模过程中，如HF组兔出现死亡，由补充组兔随机补充。HF组按预实验结果在注射CCl4后第4、5、6、10周末分别选HF组兔8只、对照组兔4只进行肝脏MRI常规轴位T1WI、T2WI序列及轴位DWI序列扫描，扫描完成后立即处死，进行病理学分期。DWI采用SE-EPI序列(b=50 s/mm2、400 s/mm2、800 s/mm2)，在ADC图上测量表观扩散系数(ADC值)。以组织病理学分期为标准，评价第4、5、6、10周ADC值与HF病理分期的相关性，并采用ROC曲线分析ADC值的诊断准确性。结果不同HF病理分期之间ADC值存在明显差异(F=5.344，P＜0.005)。随着肝纤维化的进展，肝脏实质平均ADC值相应降低；S0组和S1～S2组的ADC值均高于S3～S4组(P＜0.05)，S0组与S1～S2组的ADC值之间均无显著差异(P＞0.05)。ADC值与HF分期存在明显的相关性(r=－0.630，P＜0.001)但是S0、S1和S2三者之间以及S3和S4之间ADC值无明显差异(P＞0.1)。但相邻各组间ADC值重叠较大。结论 MR-DWI序列作为一种安全、可靠的无创性扫描技术，可为临床随访和疗效观察提供一种重要的补充手段。

Aassessment of diffusion-weighted imaging in staging liver ifbrosis in rabbits

Objective: To evaluate the accuracy of apparent diffusion coefifcient(ADC) correlates on staging liver ifbrosis.Materials and Methods:The study consisted of three groups: HF group (n=32), control group (n=15) and supplemental group (n=12). Rabbits from control and HF group underwent conventional MRI and DWI scan and the liver ADC values were measured. In HF group, eight rabbits randomly underwent MRI examinations at 4, 5, 6, 10 weeks after CCl4 administration. The correlation between ADC values and HF stages was assessed. The diagnostic performance of DWI for staging HF was compared using the receiver operating characteristic curve analysis on the basis of the histopathologic analysis of HF.Results:Signiifcant differences of ADC values were present among HF stages (F=5.344,P<0.005). The ADC values were correlated with the HF stages (r=-0.630,P<0.001). Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) were for≥S1: 75.00%, 55.56%, 85.70%, 38.50%, respectively; for≥S2: 79.2%, 58.8%, 73.1%, 66.7%; for≥S3: 87.5%, 80.0%, 73.70%, 90.9%; for S4: 87.50%, 66.67%, 38.90%, 95.7%.Conclusion:DWI can offer important assistance in staging HF as a non-invasive technique.