Lymphosonographic sentinel node biopsy of the supraglottis in a swine model

To test the feasibility of a novel contrast-enhanced ultrasound (CEUS) technique, or lymphosonography, for sentinel node biopsy (SNB) of the supraglottis in a porcine model. In this prospective, nonrandomized animal study, blue dye and ultrasound contrast agent were injected into the supraglottis in seven 50-kg Yorkshire swine. Transcutaneous CEUS was used to identify real-time lymphatic flow of contrast through lymph channels (LC) to the sentinel lymph node (SLN). SNB was carried out, visually identifying a blue node, with the assistance of intraoperative CEUS. Bilateral modified radical neck dissections were performed to search for any residual contrast-positive or blue SLNs. In each case, at least one SLN was identified by preoperative CEUS. A total of 12 nodes were identified on preoperative CEUS, and 11 of 12 nodes were stained with blue dye (91.7%). No residual blue or contrast-positive nodes were identified on neck dissection. Lymphosonographic SNB of the supraglottis in a porcine model is technically feasible, and yields results comparable to traditional blue dye–guided techniques. No “shine-through” effect or nonsequential nodal enhancement occurred. This technique holds promise for sentinel node biopsy and allows a novel method for in vivo investigation of the lymphatic system.