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.