Figure 7.

Contrast-enhanced lymphosonography in oral cancer. After microbubble injection at one or multiple peritumoral locations, contrast-enhancement of the injection site is visualized in ultrasound contrast mode. Using real-time imaging, the transportation of the microbubbles through lymphatic vessels may be followed until they accumulate in the sentinel lymph nodes. Subsequently, the neck is scanned for additional contrast-enhanced lymph nodes. Contrast-enhanced lymph nodes can be either marked for surgical resection or directly subjected to biopsy or aspiration cytology. Peritumoral injections can be repeated if necessary. (a) Schematic representation of a microbubble; (b) Principle of contrast-enhanced ultrasound (CEUS): oscillating microbubbles produce strong nonlinear scattering which can be distinguished from scattering by the surrounding tissue; (c) Contrast-enhanced ultrasonography with Sonazoid. On the left half is a contrast-enhanced image, and on the right is the B-mode image. Contrast-enhancement of sentinel lymph nodes (SLNs) (arrowheads) was observed concomitant with lymphatic ducts (arrows) draining the nodes. (Adapted with permission from [35], copyright 2019 Taylor & Francis Group: license number: 4810090088685).