Comparison of lymphatic contrast-enhanced ultrasound and intravenous contrast-enhanced ultrasound in the preoperative diagnosis of axillary sentinel lymph node metastasis in patients with breast cancer

This study aimed to compare diagnostic efficiency for axillary sentinel lymph node (SLN) metastasis between lymphatic contrast-enhanced ultrasound (LCEUS) and intravenous contrast-enhanced ultrasound (ICEUS) in patients with breast cancer. We also examined whether adding ICEUS to LCEUS could improve the diagnostic accuracy of LCEUS. Sixty-nine patients with breast cancer were recruited preoperatively. All patients underwent LCEUS followed by ICEUS, and the enhancement pattern of one SLN was analysed for each patient. The targeted SLN was marked with wire and excised during surgery. The imaging diagnosis was compared with the histopathological result. Diagnostic efficiency was compared among LCEUS, ICEUS, and the combination of LCEUS and ICEUS. The sensitivity values for LCEUS, ICEUS, and the combination of LCEUS and ICEUS were 86.2%, 82.6% and 93.1%, respectively. Specificity values for the three methods were 95.0%, 92.5% and 87.5%, respectively. Accuracy values for the three methods were 91.3%, 88.4% and 89.9%, respectively. The area under the receiver operating characteristic (ROC) curve for LCEUS was 0.906, and there was no significant difference among LCEUS, ICEUS, and the combination of LCEUS and ICEUS ( = 0.752). LCEUS may represent an accurate method for predicting SLN metastasis preoperatively. Our findings suggest that adding ICEUS to LCEUS for SLN evaluation in patients with breast cancer is unnecessary. This is the first study in which both LCEUS and ICEUS were performed for the same lymph node and the first to compare the diagnostic efficiency of LCEUS, ICEUS, and the combination of LCEUS + ICEUS.