Purpose: To demonstrate the feasibility of dynamic four-dimensional ( 4D four-dimensional ) intranodal contrast material-enhanced magnetic resonance (MR) lymphangiography with inguinal lymph node injection of gadopentetate dimeglumine.
Materials and methods: All procedures were performed in accordance with the guidelines on the use of animals in research and were approved by the animal care and use committee. Five swine underwent nonenhanced MR lymphangiography with a heavily T2-weighted MR sequence, bilateral inguinal lymph node injection of 2 mL of undiluted gadopentetate at a rate of 1 mL/min, and 60 minutes of MR imaging with T1-weighted high-spatial- and high-temporal-resolution MR angiography. Images were reviewed by a radiologist with expertise in lymphatic imaging and a pediatric cardiac MR imaging specialist for visualization of the thoracic duct ( TD thoracic duct ). Categorical variables were compared by using the exact conditional McNemar test. A difference with a P value less than .05 was considered significant.
Results: The TD thoracic duct was visualized in three of the five animals (60%) on T2-weighted images. In contrast, the TD thoracic duct was visualized in all five of the animals (100%) after contrast agent injection (P = .25). The median time for flow of the contrast agent through the lymphatic system to the TD thoracic duct outlet was 244 seconds (range, 201-387 seconds). Enhancement was seen in the TD thoracic duct up to 1 hour after injection. All animals survived without any complications.
Conclusion: Dynamic 4D four-dimensional contrast-enhanced MR lymphangiography with intranodal injection of gadopentetate dimeglumine is feasible, produces good images of the central lymphatic system, and demonstrates the time course of flow of contrast agent up the central lymphatic ducts. On the basis of the results of this initial animal experiment, it appears that dynamic 4D four-dimensional contrast-enhanced MR lymphangiography is potentially feasible and safe with commercially available contrast agents.