To evaluate the application of contrast-enhanced ultrasound (CEUS) in the breast imaging reporting and data system (BI-RADS) classification.

From November 2008 to January 2012, 298 breast lesions in 298 patients underwent baseline ultrasonography and CEUS and the pathological diagnosis was obtained. The imaging data were analyzed independently by 3 radiologists, all of whom were blinded to identi, cation, clinical histories, histopathologic results and other imaging results of the patients and were not involved in sonographic imaging. Consensus results were obtained if opinions were different. The baseline ultrasound features were analyzed at first. Then the dynamic enhancement features were analyzed. Lesions were classified according to BI-RADS. The distinctions between benign and malignant lesions were analyzed. One hundred samples were randomly selected. According to the estimate odds ratios in multiple logistic regression analysis, important indicators of CEUS were selected. Then BI-RADS classification of the whole 298 cases corrected by important CEUS indicators were obtained. The receiver operating characteristic curve was used to evaluate the diagnostic capability of BI-RADS classification before and after CEUS.

Enhancement level, perfusion modes, alteration of enhanced region, distribution of the contrast medium, edge of enhancement and tumor vessels showed statistical difference between benign and malignant lesions. After logistic regression was performed, edge of enhancement (OR=12.173), alteration of enhanced region (OR=6.182), tumor vessels (OR=4.124 ) were selected as significant factors. BI-RADS classification of baseline ultrasound were as follows, 3 cases in category 2, 132 cases in category 3, 154 cases in category 4 and 9 cases in category 5. BI-RADS classification of baseline ultrasound combined CEUS were as follows, 3 cases in category 2, 157 cases in category 3, 109 cases in category 4 and 29 cases in category 5. After CEUS, more cases are classified as Category 3 and Category 5. Before and after CEUS, areas under the ROC curve were 0.826 and 0.885 (95% confidence interval were 0.772-0.880 and 0.839-0.932).

Enhancement level, perfusion modes, alteration of enhanced region, distribution of the contrast medium, edge of enhancement and tumor vessels showed statistical difference between benign and malignant lesions. Edge of enhancement, alteration of enhanced region and tumor vessels were significant factors. Bringing CEUS into BI-RADS could reduce the number of cases of BI-RADS category 4 and reduce unnecessary biopsies.