Preliminary experience with a novel fluorescence lymphography using indocyanine green in patients with secondary lymphedema.

BACKGROUND: Lymphoscintigraphy has largely been performed to diagnose lymphedema. It is, however a time-consuming and expensive technique, which has not been covered by Japanese medical insurance since the year 2002. In this report we introduce a new imaging technique of fluorescent lymphography to diagnose lymphedema.
METHODS: Fluorescence images of subcutaneous lymphatic drainage after subcutaneous injection of indocyanine green (ICG) at the foot were obtained using a newly developed near-infrared camera system. ICG fluorescent lymphography was performed in 12 patients with secondary lymphedema and 10 healthy volunteers. The 12 patients were diagnosed with secondary lymphedema according to the medical history and lymphoscintigram, of which 11 had a history of hysterectomy with extended lymph node dissection and local radiation therapy for uterine cancer. Lymphedema developed in one patient after femorotibial artery bypass for peripheral artery occlusive disease.
RESULTS: Four abnormal fluorescent patterns of the lymph drainage were observed in lymphedema: dermal backflow (an abnormal filling of the lymph capillaries), extended fluorescent signal at the dorsum and plantar region of the foot, dilated lymph channels with proximal obliteration, and diffuse glittering of fluorescent signals with scattered twinkling of the dye. Continuous lymph channels from the injection site of the foot to the groin were observed along the medial aspect of thigh in healthy subjects.
CONCLUSION: ICG fluorescence lymphography is safe, simple, and minimally invasive. The device is portable and easy to use. The technique may be useful in clinical practice to identify presence of lymphatic disorder.