Three-dimensional demonstration of the lymphatic system in the lower extremities with multi-detector-row computed tomography: a study in a cadaver model.

Sentinel lymph node biopsy (SLNB) has had a great impact on the staging and treatment of cancer. The purpose of this study was to study the lymphatic anatomy of the lower extremities by constructing three-dimensional images using multi-detector-row computed tomography (MDCT). To select appropriate contrast media for MDCT lymphatic imaging in a cadaver, we tested four kinds of contrast media by injecting them into fresh swine kidneys. After the suitable contrast medium was selected, 10 lower extremities from 5 fresh cadavers were studied. After injection of the contrast medium, each lower extremity was scanned with high-spatial-resolution MDCT. The zinc oxide mixture was found to be the most appropriate contrast formula for MDCT imaging of cadaver lymphatics in terms of CT value and no extravasation. The high-resolution MDCT imaging revealed two different superficial lymphatic pathways in the legs. One lymphatic pathway accompanying the great saphenous vein had a constant course and was connected to the superficial inguinal lymph nodes. However, another pathway, along the small saphenous vein, was variable. Some of the deep lymphatic vessels bypassed the inguinal lymph nodes. Using a new protocol, we were able to construct three-dimensional images of the lower extremity lymphatics in a cadaver model. MDCT imaging provided novel information about two different superficial lymphatic pathways in the lower extremities.