Differentiation of High and Low Output Lymphatic Failure Using Qualitative Lymphangioscintigraphy.

Abstract

To use qualitative lymphangioscintigraphy (LAS) findings to differentiate leg edema caused by high and low output lymphatic failure. LAS was performed in legs with secondary lymphedema (LE), i.e., low output failure (N = 79), and functional venous insufficiency (FVI), i.e., high output failure (N = 56), and normal legs (N = 26). Whole body images were obtained, 15, 60, and 180 min after technetium-99m injection. The rate and timing of visualization of lymphatic structures, washout out of tracer, and presence of dermal backflow were assessed. The most significant finding for differentiating LE from other conditions was not the visualization of lymphatic structures, but the washout of the tracer from the leg trunk (LE 27%, FVI 100%, normal leg 100%, P <.0001). On the other hand, the most significant finding for differentiating FVI from other legs was the visualization of inguinal lymph nodes at 15 min (LE 11%, FVI 82%, normal leg 8%, P <.0001). We found that the lack of washout from the leg trunk was most suggestive of a low output status of the lymphatic system, while earlier visualization of inguinal lymph nodes was suggestive of a high output status.