Lymphatic Mapping for LVA with Noncontrast Lymphatic Ultrasound: How We Do It.

Recently, lymphatic ultrasonography has received increasing attention. Although there are several reports on contrast-enhanced lymphatic ultrasound as a preoperative examination for lymphaticovenous anastomosis (LVA), we have been reporting the usefulness of preoperative noncontrast lymphatic ultrasound. In this article, the detailed procedure for conducting lymphatic ultrasound during the preoperative examination of LVA is thoroughly described. The only items required for lymphatic ultrasound are an ultrasound device, an echo jelly, a straw for marking, and a marker. We use an ordinary ultrasound device with an 18-MHz linear probe. We apply the Doppler, Crossing, Uncollapsible, Parallel, and Superficial fascia index to identify the lymphatic vessels. While imagining the course of the lymph vessels, we position the probe perpendicular to the long axis of the lymphatic vessels. When a vessel is found under the superficial fascia, the probe is moved proximally to trace the vessel's path. If the vessel transverses a nearby vein without connecting to it, it is most likely a lymphatic vessel. To confirm, we ensure that the vessel does not exhibit coloration in the Doppler mode. As LVA is most effective when the dilated lymph vessels are anastomosed, we use lymphatic ultrasound to identify the most dilated lymphatic vessels in each lymphosome, and mark incision lines where suitable veins are in close proximity. No contrast agent is required; therefore, medical staff such as nurses and ultrasound technicians can autonomously conduct the test.