Novel lymphography using indocyanine green dye for near-infrared fluorescence labeling.

Lymphedema is known to be caused by many pathologic conditions; however, its diagnostic and therapeutic strategies remain to be unestablished. In this study, we investigated the usefulness of a novel lymphographic method based on fluorometric sensing using indocyanine green (ICG) dye for imaging lymphatic vessels using rat models. The real-time imaging system enabled visualization of superficial lymphatic vessels with a diameter of 0.1 mm in 33 frames/second. In addition, morphologic changes in lymphatic vessels in a radiation-induced lymphedema model were detected even at the latent stage. These results suggest that this imaging technique is acceptable as an evaluation method for the lymphatic system.