Protocol of Noncontrast High-frequency Ultrasound and Contrast-enhanced Ultrasound-guided Lymphatic Mapping for Lymphaticovenous Anastomosis Surgery.

Lymphaticovenous anastomosis (LVA) surgery, one of the main methods for lymphedema, creates connections between lymphatic vessels and adjacent veins, facilitating lymphatic drainage. Preoperative mapping of lymphatic vessels is essential for LVA surgery. Noncontrast high-frequency ultrasound (HFUS) and contrast-enhanced ultrasound (CEUS) have emerged as promising tools for lymphatic mapping. Although previous studies have demonstrated the feasibility of these methods, a standardized protocol for combining noncontrast HFUS and CEUS for lymphatic mapping is still lacking. In this study, we provide a detailed protocol of preoperative lymphatic mapping using combined HFUS and CEUS based on our practice on 150 cases. We first use CEUS to detect lymphatic vessels, which are further measured by noncontrast HFUS. Then, we use the noncontrast ultrasound to localize more lymphatic vessels and adjacent veins. We also improved the method of marking lymphatic vessels on the skin by indicating the positions of the lymphatic vessels and veins on the longitudinal section of the probe.