Dynamic contrast-enhanced computed tomography lymphangiography with intranodal injection of water-soluble iodine contrast media in microminipig: imaging protocol and feasibility

Objectives: To evaluate the optimal imaging protocol and the feasibility of intranodal dynamic contrast-enhanced computed tomography lymphangiography (DCCTL) in microminipigs.

Methods: The Committee for Animal Research and Welfare provided university approval. Five female microminipigs underwent DCCTL after inguinal lymph node injection of 0.1 mL/kg of iodine contrast media at a rate of 0.3 mL/min with three different iodine concentrations: group 1, 75 mgI/mL; group 2, 150 mgI/mL; and group 3, 300 mgI/mL. The CT values of the venous angle, thoracic duct (TD), cisterna chyli, iliac lymphatic duct, and iliac lymph node were measured; increases in CT values pre- to post-contrast were assessed as the contrast-enhanced index (CEI). Multi-detector row CT (MDCT) and volume rendering images showing the highest CEI were qualitatively evaluated.

Results: The CEI of all lymphatics peaked at 5-10 min. The mean CEI of TD at 10 min of group 2 (193.0 HU) and group 3 (201.5 HU) were significantly higher than that of group 1 (70.7 HU) (p = 0.024). The continuity and overall diagnostic acceptability of all lymphatic system components were better in group 3 (3.6 and 3.0, respectively) than group 1 (2.6 and 1.6) and group 2 (3.0 and 2.6) (p = 0.249 and 0.204).

Conclusions: The optimal imaging protocol for intranodal DCCTL could be dual-phase imaging at 5 and 10 min after the injection of 300 mgI/mL iodinated contrast media. DCCTL provided good images of lymphatics and is potentially feasible in clinical settings.

Key points: • Dynamic contrast-enhanced computed tomography lymphangiography with intranodal injection of water-soluble iodine contrast media showed the highest enhancement of all lymphatics at scan delays of 5 and 10 min. • The optimal iodine concentration for intranodal dynamic contrast-enhanced computed tomography lymphangiography might be 300 mgI/mL. • Intranodal dynamic contrast-enhanced computed tomography lymphangiography provided good images of all the lymphatic system components and is potentially feasible in clinical settings.