Perfusion contrast-enhanced ultrasound to predict early lymph-node metastasis in breast cancer

Purpose: To evaluate whether quantitative analysis of perfusion contrast-enhanced ultrasound (CE-US) could predict early lymph-node (LN) metastasis in clinically node-negative breast cancer. Materials and methods: In this prospective study, 64 breast cancer patients were selected for perfusion CE-US imaging. Regions of interest were placed where the strongest and weakest signal increases were found to obtain peak intensities (PIs; PI _max and PI _min , respectively) for time–intensity curve analyzes. The PI difference and PI ratio were calculated as follows: PI difference = PI _max −PI _min ; PI ratio = PI _max /PI _min . Results: Forty-seven cases were histologically diagnosed as negative for LN metastasis and 17 were positive. There was a significant difference in PI _min and the PI ratio between the LN-negative and -positive metastasis groups (p = 0.0053 and 0.0082, respectively). Receiver-operating curve analysis revealed that the area under the curve of PI _min and the PI ratio were 0.73 and 0.72, respectively. The most effective threshold for the PI ratio was 1.52, and the sensitivity, specificity, positive predictive value, and negative predictive value were 59% (10/17), 87% (41/47), 63% (10/16), and 85% (41/48), respectively. Conclusions: Parameters from the quantitative analysis of perfusion CE-US imaging showed significant differences between the LN-negative and -positive metastasis groups in clinically node-negative breast cancer.