How Preoperative Sentinel Lymph Node Contrast-enhanced Ultrasound Helps Intraoperative Sentinel Lymph Node Biopsy In Breast Cancer

The purpose of this study is to evaluate the value of sentinel lymph node contrast-enhanced ultrasound(SLN-CEUS)and surface tracing for the biopsy of intraoperative sentinel lymph nodes(SLN).Between June 2015 and December 2017,a total of 473 patients with early invasive breast cancer were recruited.Patients received an intradermal injection of microbubble contrast agent around the areola on the day before surgery.The locations and sizes of lymphatic channels(LCs)and SLNs were marked on the body surface using gentian violet.Then,injection of double blue dye was performed half an hour before the surgery.We compared the pathway of LCs and the location of SLNs obtained from SLN-CEUS and blue dye during surgery.Among the 473 patients,the mean number of LCs and SLNs detected by SLN-CEUS was 1.42 and 1.72,respectively,and the coincidence rate was 98.1% compared with blue dye during surgery.The median distance of SLN to skin measured by preoperative CEUS and blue dye was 1.95 ± 0.69 cm and 2.03 ± 0.87 cm,P =0.35.There were three enhancement patterns of SLN in our research,including homogeneous enhancement,inhomogeneous enhancement,and no enhancement,with the sensitivity,specificity,negative predictive value,and positive predictive value of SLN-CEUS for the diagnosis of SLN of 96.73%,91.80%,88.17%,and 97.82%,respectively.SLN-CEUS with skin marking can identify the pathway of LCs and the location of the SLN before surgery,measure the distance of the SLN to skin,and determine if the SLN is metastatic.SLN-CEUS can be used as an effective complement of the blue dye method.