MicroCT liver contrast agent enhancement over time, dose, and mouse strain

Abstract

Purpose: The aim of this study was to examine strain differences in the uptake of Fenestra liver contrast agent (LC) in Nude, C57, and severe-combined immunodeficient (SCID) mice. In addition, we aimed to determine optimum dosing and to determine if there are positron emission tomography (PET)-attenuation effects on 2-deoxy-2[F-18]fluoro-D-glucose (FDG) values due to Fenestra LC.

Procedures: Nude, C57, and SCID mice were injected via tail vein at 5.0, 7.5, 10.0, and 15.0 ml/kg with contrast agent and imaged using micro computed tomography (microCT) 2 h after uptake and then daily up to 7 days. Mice were imaged by microPET/CT with FDG, with or without contrast agent.

Results: Significant variations in contrast were observed between mouse strains. SCID mice had significantly more spleen uptake of contrast than the other strains, and C57 mice had significantly more liver uptake of contrast than other strains. Across all strains, the spleen showed significantly higher uptake and duration of contrast than liver. Only the heart showed a significant attenuation of FDG uptake following contrast administration.

Conclusions: Strain-specific variations in Fenestra LC uptake and signal duration were observed. At 7.5 ml/kg, this contrast agent is effective for imaging for 1 day, whereas at 15 ml/kg, it can be used up to 1 week. Fenestra LC does not appear to attenuate FDG uptake at 15 ml/kg for most tissues; therefore, it can be used in conjunction with microPET imaging studies.