Near InfraRed Fluorescence Imaging of Lymphatic Transport Using Indocyanine Green

Lymphedema from various etiologies (i.e. infection, cancer, surgery, and rheumatoid arthritis) remains a major health concern. Efforts to develop effective treatments for this condition have been limited by the absence of quantitative outcome measures for lymphatic function. Published articles have supported the fact that human lymphatic contractions can be readily visualized after intradermal administration of micrograms of Indocyanine Green using laser-induced fluorescence. The use of lasers imposes a risk of eye injury that requires protective eyewear. To address the risk of laser-induced injury, an imaging system was developed by Drs. Ronald Wood and Jay Reeder in a collaborative effort at the University of Rochester. In place of a laser, this system utilizes a tungsten-halogen lamp fitted with a bandpass filter and a multispectral camera for real-time image acquisition and display. This phase 1 study will examine the validity and reliability of this instrument to measure lymphatic transport, contractions, and pressure in the arms of healthy research subjects and establish baseline parameters for subsequent evaluation of rheumatoid arthritis patients in later studies. Indocyanine Green is a dye that has been used clinically for over 50 years to evaluate hepatic clearance, cardiovascular function testing, and retinal angiography. Indocyanine Green has typically been administered intravenously at concentrations of 2.5 mg/ml at total doses of 25 mg in adults. In this study, intradermal administration of micrograms of Indocyanine Green will be used to establish useful dose ranges and concentrations. The dosage regimen for this study is based on prior demonstrations in published articles of successful noninvasive imaging of lymphatic contractions after intradermal administration of microgram amounts of Indocyanine Green.