Near-Infrared Fluorescent Lymphography

Abstract

Near-infrared fluorescent lymphography or indocyanine green (ICG) lymphography is becoming popular in the management of lymphedema. ICG lymphography can clearly visualize superficial lymph flows in real time without radiation exposure. ICG lymphography findings change from normal «linear» pattern to abnormal «dermal backflow (DB)» patterns (mild DB, «splash» pattern; moderate DB, «stardust» pattern; severe DB, «diffuse» pattern) with progression of lymphedema. Splash pattern represents reversible change; on the other hand «stardust» and «diffuse» patterns represent irreversible change. ICG lymphography-based DB stages [arm DB (ADB) stage, leg DB (LDB) stage, genital DB (GDB) stage, and facial DB (FDB) stage] allow pathophysiological severity staging for secondary lymphedema. ICG lymphography also allows classification of primary lymphedema: proximal DB (PDB), distal DB (DDB), less enhancement (LE), and no enhancement (NE) patterns. ICG velocity, representing lymph pump function, decreases with lymphedema progression. ICG lymphography is also used as pre- and intraoperative navigation for lymphatic surgeries such as lymphaticovenular anastomosis, lymph node transfer, and liposuction. In «linear» pattern region, a surgeon can easily find lymphatic vessels. Progression of ICG lymphography pattern represents lymphosclerosis progression. Dynamic ICG lymphography, dual-phase lymphography, allows pathophysiological severity staging, evaluation of lymph pump function, and navigation for lymphatic surgery with only one ICG injection. Dynamic ICG lymphography is useful for the evaluation and treatments of primary and secondary lymphedema.