Near-infrared fluorescence imaging of lymphatics in head and neck lymphedema

Abstract

Treatment of lymphatic disease is complicated and controversial, due in part to the limited understanding of the lymphatic system. Lymphedema (LE) is a frequent complication after surgical resection and radiation treatment in cancer survivors, and is especially debilitating in regions where treatment options are limited. Although some extremity LE can be effectively treated with manual lymphatic drainage (MLD) therapy or compression devices to direct proximal lymph transport, head and neck LE is more challenging, due to complicated geometry and complex lymphatic structure in head and neck region. Herein, we describe the compassionate use of an investigatory technique of near-infrared (NIR) fluorescence imaging to understand the lymphatic anatomy and function, and to help direct MLD in a patient with head and neck LE. Immediately after 9 intradermal injections of 25 μg indocyanine green each around the face and neck region, NIR fluorescence images were collected using a custom-built imaging system with diffused excitation light illumination. These images were then used to direct MLD therapy. In addition, 3-dimensional (3D) surface profilometry was used to monitor response to therapy. NIR fluorescence images of functioning lymphatic vessels and abnormal structures were obtained. Precise geometries of facial structures were obtained using 3D profilometry, and detection of small changes in edema between therapy sessions was achieved. NIR fluorescence imaging provides a mapping of lymphatic architecture to direct MLD therapy and thus improve treatment efficacy in the head and neck LE, while 3D profilometry allowed longitudinal assessment of edema to evaluate the efficacy of therapy.