目的 定量分析肝脏占位性病变 不同b值条件下ADC值的差异，探讨最佳 b值选择及鉴别肝脏良恶性病变的ADC值 阈值。方法 采用Siemens Verio 3.0T磁 共振设备，对96例肝脏占位病变行DWI扫 描，b值设定为200，500，800s/mm2 ，分 别测量不同b值条件下病灶的ADC值并进行 统计学分析。结果 1、随b值增加，各种 病变的ADC值均逐渐下降；各种病变b200 组与b500、800组之间的ADC值差异均具 有统计学意义；而b500与b800组之间， 除肝细胞癌外无明显差异；b值取500、 800s/mm2 时，可获得相对稳定的ADC值。 2、不同b值下，肝血管瘤与其他各组病 变间的ADC值差异均具有统计学意义，肝 脏恶性肿瘤间、FNH与转移瘤间无统计学 差异；当b值为500、800s/mm2 时，肝细胞 癌、胆管细胞癌与FNH差异具有统计学意 义。3、通过ROC曲线分析获得鉴别肝脏良 恶性病变的最佳b值为500s/mm2 ，以ADC值 1.27×10-3mm2 /s为最佳阈值，鉴别良恶性 病变的敏感度、特异度为91.4%、85.2%。 结论 通过不同b值条件下ADC值的定量分 析，有助于肝脏占位性病变的鉴别诊断， 是对常规MR检查的有益补充。

Objective Quantitative analysis of hepatic occupying lesions under different b values of ADC, to explore the optimal selection of b value and differential diagnosis of malignant and benign liver lesions of the ADC threshold. Methods 96 cases of hepatic occupying lesions were examined by Siemens 3.0T MR-DWI, b value were set as 200, 500, 800s/mm2 . The ADC values of various lesions among different b values were measured respectively and analyzed statistically. Results 1 With the increase of b value, the ADC value of various lesions decreased. The differences of ADC value between the b200 group and the b500, 800 group were statistically significant.And between the b500 and the b800 group, there were no significant difference except for HCC.When the b value was 500, 800s/mm2 , the ADC value obtained relatively stable. 2 In three kinds of b value, the ADC values of hemangioma and the other group lesions were statistically significance while there were no significant differences between malignant tumors, also there were no significant difference between FNH and metastasis.When the b value was 500 or 800s/mm2 , the ADC values of FNH and HCC, cholangiocarcinoma were statistically significance. 3 Taking ROC curve，500s/mm2 was the optimal b value in the diagnosis of hepatic occupying lesions.The best threshold of ADC in the differential diagnosis of benign and malignant lesions was 1.27×10-3mm2 /s, while the sensitivity and specificity were 91.4% and 85.2%. Conclusion Quantitative analysis ADC values in different b values is helpful for the differential diagnosis of liver occupying lesions, which is a useful supplement for conventional MR examination.