Elucidation of Percutaneously Accessible Lymph Nodes in Swine: A Large Animal Model for Interventional Lymphatic Research

Purpose: To define percutaneously accessible, anatomically reproducible swine lymph nodes using magnetic resonance imaging, ultrasound, and ethiodized oil (Lipiodol; Guerbet, Bloomington, Indiana) lymphangiography. Materials and Methods: Five adult female swine (Yorkshire, 50-60 kg) were used. Under general anesthesia, T1-weighted and T2-weighted, coronal and axial images of the entire swine were obtained. The animal's extrathoracic, extraperitoneal soft tissues from the neck to the groins were examined with ultrasound. Lymph nodes ≥ 1 cm were marked before the animal was transferred to the angiography suite. Under ultrasound guidance, the nodes were accessed, and lymphangiograms were obtained. The imaging findings between the 3 modalities were correlated, and the lymph node drainage was mapped. Results: Four lymph nodes/lymph node groups were identified that were reproducible in all 5 animals, > 1 cm and percutaneously accessible: submandibular node, superficial cervical lymph node group, subiliac node, and superficial inguinal lymph node group. Drainage of these nodes mirrored human anatomy. The abdominopelvic lymphatics formed a retroperitoneal cisterna chyli and drained cephalad via a thoracic duct. Conclusions: The swine exhibits reproducible lymphatic anatomy with at least 4 percutaneously accessible lymph nodes/lymph node groups. Based on these results, the swine may be a suitable large animal model for research into lymphatic interventions.