“A fresh cadaver study on indocyanine green fluorescence lymphography: A new whole body imaging technique for investigating the superficial lymphatics.”

Background: Identification of the lymphatic system in cadavers is painstaking because lymphatic vessels have very thin walls and are transparent. Selection of appropriate contrast agents is a key factor for successfully visualizing the lymphatics. In this study, we introduce a new imaging technique of lymphatic mapping in whole body of fresh cadavers. Methods: Ten fresh human cadavers were used for this study. We injected 0.1 mL of indocyanine green fluorescence (ICG) solution subcutaneously at multiple spots along the watershed lines between lymphatic territories and hand and foot regions. After the body was scanned by the near infrared camera system, fluorescent tissues were harvested and histological examination was performed under the microscope equipped with the infrared camera system to confirm they were the lymphatics. Results: Subcutaneously injected ICG was immediately transported into the lymphatic vessels after gentle massage on the injection points. Sweeping massage along the lymphatic vessels facilitated ICG transport inside the lymphatic vessel to move towards the lymph nodes. The lymphatic system was visualized well in the whole body. Histological examinations confirmed that ICG was detected in the lymphatic lumens specifically, even when located far from the injected points. Conclusions: The lymphatic system could be visualized in whole body fresh cadavers, as in living bodies, using ICG fluorescence lymphography. Compatibility of ICG lymphography would be open to use cadaveric specimens for macro and microscopical analysis. Financial Disclosure Statement: The authors have no financial interest to declare in relation to the content of this article. Acknowledgments: This work was supported by the Japan Society for the Promotion of Science via Grants-in-Aid for Scientific Research (KAKENHI Award Number: 16K20358) and Research Foundation for the Electrotechnology of Chubu. Corresponding author: Akira Shinaoka, Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Science, 2-5-1 Shikata-cho, Kita-ku, Okayama-shi, 700-8558, Japan. Email: a-shinaoka@okayama-u.ac.jp ©2018American Society of Plastic Surgeons