Assessment of Lymphatic Contractile Function After Manual Lymphatic Drainage Using Near-Infrared Fluorescence Imaging

Objective: To investigate the feasibility of assessing the efficacy of manual lymphatic drainage (MLD), a method for lymphedema (LE) management, by using near-infrared (NIR) fluorescence imaging. Design: Exploratory pilot study. Setting: Primary care unit. Participants: Subjects (N=10; age, 18-68y) with a diagnosis of grade I or IT LE and 12 healthy control subjects (age, 22-59y). Intervention: Indocyanine green (25 mu g in 0.1 mL each) was injected intradermally in bilateral arms or legs of subjects. Diffused excitation light illuminated the limbs, and NIR fluorescence images were collected by using custom-built imaging systems. Subjects received MLD therapy, and imaging was performed pre- and posttherapy. Main Outcome Measures: Apparent lymph velocities and periods between lymphatic propulsion events were computed from fluorescence images. Data collected pre- and post-MLD were compared and evaluated for differences. Results: By comparing pre-MLD lymphatic contractile function against post-MLD lymphatic function, results showed that average apparent lymph velocity increased in both the symptomatic (+23%) and asymptomatic (+25%) limbs of subjects with LE and control limbs (+28%) of healthy subjects. The average lymphatic propulsion period decreased in symptomatic (-9%) and asymptomatic (-20%) limbs of subjects with LE, as well as in control limbs (-23%). Conclusions: We showed that NIR fluorescence imaging could be used to quantify immediate improvement of lymphatic contractile function after MLD.