Diagnostic efficacy of the diffusion weighted imaging in the characterization of different types of breast lesions

PURPOSE: To evaluate the diagnostic efficacy of quantitative Diffusion-weighted imaging (DWI) in the characterization of breast lesions of mass and non-mass enhancement (NME) types. MATERIALS AND METHODS: After the institutional review board gave approval, DWI exams of 267 women with 212 suspicious masses, 73 NMEs were retrospectively analyzed. Apparent diffusion coefficients (ADCs) of benign and malignant lesions were compared. Cutoff values were obtained by receiver operating characteristics analysis. Diagnostic accuracies of DWI for masses and NMEs were compared with the use of Chi-square test. The effect of the lesions histologic subtypes and size on diagnostic accuracies was evaluated. RESULTS: ADCs were significantly lower in malignants than in benigns for both masses (0.75 versus 1.21 × 10(-3) mm(2) /s,) and NMEs (0.79 versus 1.06 × 10(-3) mm(2) /s)(P < 0.001). Cutoff value was 0.90 × 10(-3) mm(2) /s for both lesion types. The accuracy of DWI was lower in NMEs (76.7%) than masses (89.2%) (P = 0.008) unrelated to lesion size. There was more overlap in ADCs of the benign and malignant NMEs due to the lower ADCs of the benign histologies of this group. CONCLUSION: Despite the lower diagnostic accuracy of DWI in NMEs, it could be helpful in the characterization of suspicious breast lesions of both mass and NME types.