Yukihiro Hama MD,PhD, Presenter: Nothing to Disclose

Yoshinori Koyama MD, Abstract Co-Author: Nothing to Disclose

Yasuteru Urano PhD, Abstract Co-Author: Nothing to Disclose

Marcelino Bernardo, Abstract Co-Author: Nothing to Disclose

Peter L. Choyke MD, Abstract Co-Author: Researcher, General Electric Company Researcher, Koninklijke Philips Electronics NV Researcher, Becton, Dickinson and Company Researcher, Siemens AG

Hisataka Kobayashi MD, PhD, Abstract Co-Author: Nothing to Disclose

The lymphatic system is difficult to study due to the small size of its vessels and its difficult accessibility. The purpose of this study was to establish a non-invasive optical lymphangiographic technique to visualize dual lymphatic flows to the axillary lymphatics from the breast and from the ipsilateral extremity in order to better understand the mixing of these two lymphatic basins using real time imaging.

Athymic mice (n=10) received injections of a quantum dot optical agents into the middle phalange of the left upper extremity (Qdot 800) and into the left breast (Qdot 705). Immediately after injection, wavelength-resolved spectral imaging was carried out. The different colors of the quantum dots allowed real time imaging of the lymphatic flow. The lymphatic drainage territory of each contrast agent was assessed before and after removal of the skin. After in vivo lymphangiography, the axillary, lateral thoracic and cervical lymph nodes were extracted for ex vivo fluorescence imaging and fluorescence microscopy to validate the in vivo imaging.

Two-color lymphangiography successfully visualized lymphatic vessels as well as the lymphatic drainage territory in all 10 mice. Eight axillary lymph nodes received two different lymphatic flows simultaneously from the breast and from the upper extremity. Varying patterns of intralymphatic co-enhancement indicating very variable drainage patterns were observed in these 8 mice. Two axillary lymph nodes received only one lymphatic flow either from the breast (n=1) or from the upper extremity (n=1). Ex vivo fluorescence imaging and fluorescence microscopy of resected lymph nodes validated the lymphatic drainage found in the in vivo lymphangiography in all 10 mice.

Dual color quantum dot imaging of the lymphatics demonstrates a highly variable pattern of drainage from the breast and upper extremities into the axillary lymph nodes. Quantum dot imaging provides an excellent means of studying lymphatic flow in vivo.

Dual color optical fluorescence imaging using quantum dots can provide insight into mechanisms of drainage from different lymphatic basins that may lead to prevention of disorders such as lymphedema.

Hama, Y, Koyama, Y, Urano, Y, Bernardo, M, Choyke, P, Kobayashi, H, Two-color Optical Lymphangiography of Axillary Lymph Nodes Using Macromolecular Optical Contrast Agents.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4433069.html