Contrast enhancement of the liver of anesthetized, paralyzed, and artificially ventilated rabbits was measured during suspended respiration prior to, during, and after the intravenous infusion of meglumine diatrizoate at doses of 208, 416, and 624 mg I/kg. Infusion time was 30 seconds, and, at the highest dose, infusion times of 1, 2, and 4 minutes were also used. Highest contrast enhancement values were obtained at the conclusion of each infusion, with contrast enhancement increasing proportionately with increase in dose. Highest enhancement was obtained at all times studied from the most rapid infusion. Unlike cranial CT, optimum hepatic contrast enhancement in body CT requires rapid contrast medium injection with immediate CT scanning with a very fast scanner.