Congratulations to Eric Livingston and Jon Frank, who were co-first authors on the best poster award for the Cardiovascular and Pulmonary section at the 2024 WMIC conference in Montreal, CA. The poster titled, “Evaluation of the new CT contrast agent VivoVist for vascular and liver imaging in mouse models” examined three different commercially available contrast agents over a 30 day period in mice. The Small Animal Imaging facility has worked to expand our CT contrast pipeline to enhance our ability to image soft tissues in small animals.
Abstract
Small animal CT imaging provides excellent bone structure, lung imaging, and gross anatomy with high resolution. However, it is limited in providing high quality tissue contrast in vivo. While several blood pool CT contrast agents have been developed to enhance vascular contrast for preclinical imaging, their enhancement capacity and performances are different in mouse models. VivoVistTM is the most recent commercially available blood pool CT contrast agent for preclinical applications. This study aimed to conduct an independent evaluation of its radiopacity and tissue enhancement by comparison with other preclinical CT contrast agents. Materials and Methods: Normal healthy nude mice were administered with one of the three contrast agents: VivoVist, MvivoAu, and Fenestra-HDVC. CT imaging was conducted before and 5 minutes after injection, with follow-up scans at 1, 4, 24, 48, 96, and 168 hours (7 days) after injection. Tissue intensity and enhancement ratio to the pre-injection level were quantified at all timepoints for each contrast agent. Results: At 5 min post injection, VivoVist had the highest blood enhancement level compared to MvivoAu, and Fenestra-HDVC. On the other hand, VivoVist had the fastest blood clearance among the three contrast agents with a blood half-life of 3.4 hours. The half-life for MvivoAU and Fenestra-HDVC was 31.6 hours and 9.7 hours, respectively. Late phase CT imaging showed that VivoVist had the highest liver enhancement among the three contrast agents and remained high over the 7 -day imaging duration. Biodistribution assessment revealed that the spleen uptake of VivoVist was extremely high, and future spleen tissue histology is needed to assess its tissue toxicity. Conclusions: VivoVist has demonstrated a promising contrast agent for CT imaging in mouse models for vascular and liver imaging with a limited blood circulation half-life.