Preoperative Sentinel Node Identification With Ultrasound Using Microbubbles in Patients With Breast Cancer

OBJECTIVE. Sentinel lymph node (SLN) biopsy is the standard procedure for axillary staging in early breast cancer. Lymphatic imaging after peritumoral microbubble injection has been described in animal models. The aim of this study was to identify and localize SLNs preoperatively by contrast-enhanced sonography after intradermal injection of microbubbles in patients with breast cancer. SUBJECTS AND METHODS. Eighty consecutive consenting patients with primary breast cancer were recruited. Patients received a periareolar intradermal injection of microbubble contrast agent. Breast lymphatics were visualized by sonography and followed to the axilla to identify SLNs. A guidewire was deployed to localize the SLN. The next day, patients underwent standard tumor excision and SLN biopsy. RESULTS. In 71 (89%) of the 80 patients, SLNs were identified and guidewires were inserted. In these patients, operative findings using conventional radioisotope and blue dye techniques confirmed that the wired nodes were SLNs. Fourteen patients were found to have metastases in SLNs. In these patients, the SLNs were identified correctly and were localized with guidewires before surgery. CONCLUSION. SLNs may be identified and localized before surgery using contrast-enhanced sonography after injection of microbubbles.