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 II LE and 12 healthy control subjects (age, 22-59y).

Intervention: Indocyanine green (25 μg 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.