目的对比正常乳腺及乳腺良、 恶性病变的表观弥散系数(ADC)，探讨DWI 在乳腺良恶性病变中的诊断价值。方法 回顾分析行乳腺MRI检查并经病理证实的 177例乳腺病变，比较良、恶性病变及正 常乳腺组织ADC值的差异，采用接受者工 作特征曲线(ROC)确定良恶性病变的ADC界 值；比较ADC值在乳腺良恶性病变定性诊 断中的效能。结果 177例乳腺病变中良 性112例，恶性65例，正常乳腺177例， 其平均ADC值分别为(1.57±0.25)×10- 3 m m2 /s、(1.11±0.32)×10 - 3m m2 /s、 (1.72±0.22)×10-3mm2 /s，良恶性病变 ADC界值为1.23×10-3mm2 /s，其敏感性 和特异性分别为80.42%和92.13%。； 按病变形态分组：肿块性病变144 例，恶性47例，良性97例，平均ADC 值分别为(1.06±0.27)×10- 3m m2 /s、 (1.58±0.26)×10-3mm2 /s，ADC界值为 1.23×10-3mm2 /s，其敏感性和特异性分 别为85.17%和92.84%。；非肿块性病变 33例，恶性18例，良性15例，平均ADC 值分别为(1.25±0.40)×10- 3m m2 / s、 (1.50±0.18)×10-3mm2 /s，ADC界值为 1.36×10-3mm2 /s，其敏感性和特异性分别 为77.81%和80.35%。结论 乳腺恶性病变 的ADC值低于良性病变，根据ADC界值可以 鉴别良、恶性，对肿块性病变和非肿块性 病变应采用不同的ADC界值，DWI在鉴别乳 腺良恶性病变与正常乳腺组织时也有一定 价值。

Objective To determine the diagnostic potential of Diffusion-weighted MR Imaging to differentiate between benign and malignant breast lesions by comparing apparent diffusion coefficient (ADC) among normal breast tissue, benign and malignant breast lesions. Methods Retrospective analysis of 177 pathologically confirmed breast lesions examined using EPI-DWI and compare the mean ADC among normal breast tissue, benign and malignant breast lesions. The cut-off ADC value for malignant lesion was determined using receiver operating characteristic (ROC) curve analysis. The diagnostic accuracy of DWI was compared in breast mass and non-mass lesions. Results Mean ADC values for benign(112/177), malignant(65/177) breast lesions and normal breast tissue(177) were (1.57±0.25)×10-3mm2 /s, (1.11±0.32)×10-3mm2 / s and (1.72±0.22)×10-3mm2 /s, respectively. With a cut-off value of 1.23×10-3mm2 / s for ADC in ROC analysis, 80.42% sensitivity and 92.13% specificity were achieved. Among 177 lesions 144 were mass and 33 were non-mass. The mean ADC of malignant mass lesions [(1.06±0.27)×10-3mm2 /s] was statistically lower than that of benign ones [(1.58±0.26)×10-3mm2 /s]. The sensitivity and specificity of the ADC with a threshold of [1.23×10-3mm2 /s] was 85.17﹪ and 92.84﹪respectively. The mean ADC of malignant non-mass lesions [(1.25±0.40)×10-3mm2 /s] was statistically lower than that of benign ones [(1.50±0.18)×10-3mm2 /s]. The sensitivity and specificity of the ADC with a threshold of [1.36×10-3mm2 /s] was 77.81﹪ and 80.35﹪respectively. Conclusion The ADC is an effective parameter in distinguishing between malignant and benign breast lesions. The cut-off values of ADCs are different between mass and non-mass lesions. DWI of the breast can help differentiate benign and malignant breast lesions from normal breast tissue.