表观扩散系数在乳腺病变诊断中的应用价值

The Diagnostic Value of Apparent Diffusion Coefficient in Breast Lesions

目的:对比乳腺良、恶性病变的表观扩散系数(apparent diffusion coefficient,ADC),探讨DWI在乳腺病变中的诊断价值。材料和方法:搜集术前行MR检查并经病理证实的236例乳腺病变,采用平面回波-扩散加权成像序列(EPI-DWI);测量病变区和对侧正常乳腺腺体的ADC值,应用t检验比较良、恶性病变及正常腺体ADC值的差异,采用接收者工作特征曲线(receiver operating characteristic curve,ROC)确定良、恶性病变的ADC界值;根据BI-RADSMRI将乳腺病变分为肿块性病变和非肿块性病变,比较ADC值在两组病变中定性诊断效能。结果:236例乳腺病变中,恶性病变ADC值[(1.08±0.32)×10-3mm2/s]显著低于良性病变[(1.48±0.35)×10-3mm2/s],差异有统计学意义(P=0.01);根据ROC曲线确定ADC界值为1.25×10-3mm2/s,诊断敏感性和特异性分别为78.2%和77.5%。肿块性病变良、恶性ADC界值为1.15×10-3mm2/s(敏感性和特异性分别为79.8%和81.8%),非肿块性病变良、恶性ADC界值为1.35×10-3mm2/s(敏感性和特异性分别为78%和72%)。结论:根据ADC界值可以鉴别乳腺良、恶性病变;对肿块性病变和非肿块性病变应采用不同的ADC界值;DWI对肿块性病变的诊断效能优于非肿块性病变。

Purpose To evaluate the diagnostic value of apparent diffusion coefficient（ADC）as measured by diffusion-weighted MR Imaging（DWI）in benign and malignant breast lesions.Materials and Methods Two hundred and thirty-six patients with breast lesions underwent magnetic resonance（MR）DWI using echo planar imaging（EPI）technique.Pathological examination was performed for all the beast lesions after MR imaging.The mean ADCs were compared between malignant and benign lesions and disease-free contralateral breast tissues.The threshold ADC value for identifying malignant lesions was determined using a receiver operating characteristic（ROC）curve analysis.The beast lesions were divided into two types according to the BI-RADS criteria：mass and non-mass lesion.The performance of ADC in identifying breast mass and non-mass lesions was also determined.Results In all the patients,236breast lesions were found by MR imaging.The mean ADCs of malignant lesions were significantly lower than that of benign lesions[（1.08±0.32）×10^-3 mm^2/s vs（1.48±0.35）×10^-3 mm^2/s,P=0.01].The sensitivity and specificity of the ADCs for identifying malignant lesions using a threshold of less than 1.25×10^-3 mm^2/s was 78.2%and 77.5%,respectively.For mass lesions,the sensitivity and specificity of the ADCs for identifying malignant lesions using a threshold of less than 1.15×10^-3 mm^2/s was 79.8%and 81.8%,respectively.For non-mass lesions,the sensitivity and specificity of the ADCs for identifying malignant lesions using a threshold of less than 1.35×10^-3 mm^2/s was 78%and 72%,respectively.Conclusions The ADC value as measured by MR DWI is an effective parameter for distinguishing malignant from benign breast lesions.The cut-off value for ADCs is different between mass and non-mass lesions.The diagnostic performance of DWI is better for mass lesion compared to non-mass lesions.