Figure 3.

Contrast agent migration from the injection site into the lymph vessels and nodes. Upon microbubble injection, unidirectional transport of microbubbles away from the injection site, through an afferent lymph vessel into a draining lymph node can be observed with CEUS (A1). Image (B1) shows the trafficking of microbubble contrast signal through branched lymph vessels. In (C1), the CEUS image shows a lymph node connected to one afferent lymph vessel and 3 efferent lymph vessels that take the contrast agents further away from the injection site. Corresponding B-mode images are shown in (A2), (B2) and (C2), respectively. Images were obtained after injection of mRNA-loaded microbubbles in different female dogs. The injection site is marked as “i.s.” (unless outside of the field-of-view), arrows indicate lymph nodes and asterisks point out lymph vessels. Time after microbubble injection is noted on the CEUS images (in min:s).