ObjectiveTo assess the values of MRI, ultrasound (US), and X-ray in the differential diagnosis of benign and malignant breast lesions. MethodsThe image data of 50 breast lesions confirmed with histopathology were analyzed retrospectively and the values of MRI, US and X-ray mammography in the differential diagnosis of benign and malignant breast lesions based on the breast imaging reporting and data system (BI-RADS) were assessed. The diagnostic efficiency of MRI, US, and X-ray in 50 benign and malignant breast lesions were compared using receiver operating characteristics (ROC) curves. The areas of ROC curves of MRI, US, and X-ray were calculated with Z test using SPSS 16.0. ResultsThere were 44 patients with 50 breast lesions, 26 malignant lesions, 24 benign lesions. Based on the BI-RADS, according to X-ray imaging features, 26 malignant breast lesions were classified as 5 lesions of category 5, 7 lesions of category 4, 6 lesions of category 3, 3 lesions of category 2, 1 lesion of category 1, 4 lesions of category zero. Twenty-four benign breast lesions were classified as 1 lesion of category 4, 3 lesions of category 3, 4 lesions of category 2, 13 lesions of category 1, 3 lesions of category zero. According to the characteristics of US findings, 26 malignant breast lesions were classified as 17 lesions of category 5, 4 lesions of category 4, 1 lesion of category 3, 1 lesion of category 2, 3 lesions of category 1. Twenty-four benign breast lesions were classified as 1 lesion of category 5, 2 lesions of category 4, 4 lesions of category 3, 14 lesions of category 2, 2 lesions of category 1, 1 lesion of category 0. According to MRI imaging findings, 26 malignant breast lesions were classified as 6 lesions of category 5, 18 lesions of category 4, 1 lesion of category 3, 1 lesion of category 1. Twenty-four benign breast lesions were classified as 20 lesions of category 1, 3 lesions of category 2, 1 lesion of category 3. The area under the ROC curve of the MRI, US, and X-ray was 0.977, 0.835, and 0.764, respectively. The differences of MRI with US (Z=2.05, P < 0.05) and MRI with X-ray mammography (Z=2.81, P < 0.05) were statistically significant. While the difference of US with X-ray mammography (Z=0.73, P > 0.05) was't statistically significant. ConclusionsDynamic contrast-enhanced MRI is an accurate examination in the differential diagnosis of benign and malignant breast lesions. The differential diagnostic efficiency of MRI is significantly better than those with US and X-ray.