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,synthesized and injected into rats via the tail vein at 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.