Diffusion-weighted MR imaging of breast mass and non-mass lesion

Objective To evaluate the efficiency of Diffusion-weighted MR Imaging in differentiating breast mass and non-mass lesion by comparing apparent diffusion coefficient(ADC) of malignant lesion with that of benign one.Methods Two hundreds and ten pathologically confirmed breast lesions were examined using EPI-DWI(b values=0,1000 s/mm2);One-way analysis of variance was applied to compare the mean ADC of malignant lesions with that of benign lesions.The threshold ADC value for malignant lesion was determined using receiver operating characteristic(ROC) curve analysis.Each lesion was classified into either mass or non-mass lesion.The diagnostic accuracy of DWI was compared in breast mass and non-mass lesions.Results Among 150 mass lesions 100 were malignant and 50 were benign.The mean ADC of malignant lesions [(1.0 ± 0.3)×10-3mm2/s] was statistically lower than that of benign ones [(1.5±0.3)×10-3mm2/s].The sensitivity and specificity of the ADC for diagnosis of malignant lesions with a threshold of 1.2×10-3mm2/s was 80﹪ and 82﹪ respectively.Among 60 non-mass lesions 40 were malignant and 20 were benign.The mean ADC of malignant lesions [(1.2±0.3)×10-3mm2/s] was statistically lower than that of benign lesions [(1.5±0.4)×10-3mm2/s].The sensitivity and specificity of the ADC for diagnosis of malignant lesions with a threshold of 1.4×10-3mm2/s was 78﹪ and 72﹪ respectively.Conclusion The ADC is an effective parameter in distinguishing between malignant and benign breast lesions.The diagnostic performance of DWI is better for mass lesion compared to that of non-mass lesions.The cut-off values of ADCs are different between mass and non-mass lesions.