CT visualization of blood pool in rats by using long-circulating, iodine-containing micelles.

RATIONALE AND OBJECTIVES

Small, long-circulating particulate carriers of contrast agents, such as micelles, are potentially useful in computed tomographic (CT) blood-pool imaging. An iodine-containing amphiphilic block-copolymer consisting of iodine-substituted poly-L-lysine (MPEG-iodolysine) forms micelles in an aqueous solution. The biodistribution and CT depiction of these radiopaque micelles were therefore studied in rats.

MATERIALS AND METHODS

MPEG-iodolysine micelles were synthesized and injected into rats via the tail vein at a dose of 170 mg iodine per kilogram. Three animals were used, and tissue enhancement was followed on serial CT scans.

RESULTS

MPEG-iodolysine block-copolymer forms particulates with an average diameter of 80 nm and an iodine content of 33.8%. After intravenous injection into rats, the agent produced noticeable and sustained enhancement of the blood pool (aorta and heart), liver, and spleen for least 3 hours.

CONCLUSION

In rats, MPEG-iodolysine micelles were a long-lived blood-pool contrast agent useful for CT.