Contrast enhancement of liver and spleen in the dog was obtained after intravenous administration of brominated radioopaque liposomes (ROL) (1-5 micron in diameter. Computed tomographic (CT) numbers generated before and after 3 hours of ROL administration demonstrated an increase in hepatic attenuation. ROL are biodegradable lipid vesicles that can be subjected to further physicochemical modifications (size, charge composition) that alter their biodistribution and pharmacokinetics. These changes can result in improved hepatosplenic contrast enhancement.