PURPOSE
To investigate how reduction in cardiac output affects the magnitude and timing of aortic and hepatic contrast medium enhancement during abdominal computed tomography (CT).
MATERIALS AND METHODS
Eight 20-30-kg pigs underwent CT before and after pharmacologic reduction of cardiac output (measured by means of thermodilution). Each CT study consisted of 53 dynamic images acquired every 5 seconds at a fixed level through the midliver after intravenous injection of contrast medium (concentration, 282 mg of iodine per milliliter; dose, 2 mL per kilogram of body weight; injection rate, 2 mL/sec). Curves of contrast medium enhancement versus time were measured. Changes in the magnitude and timing of aortic and hepatic enhancement were compared with the reduction in cardiac output.
RESULTS
With reduction in cardiac output, the time from the injection start to the arrival of the contrast medium bolus in the aorta (P < .01) and the times from injection completion to peak aortic (P < .01) and peak hepatic (P < .01) enhancement increased. As cardiac output decreased, peak aortic enhancement increased proportionally (P < .01). Peak hepatic enhancement increased only slightly and correlated weakly with the decrease in cardiac output (P = .07).
CONCLUSION
As cardiac output decreases, the times to the arrival of the contrast medium bolus in the aorta and to peak aortic and hepatic enhancement increase. Reduction in cardiac output results in a substantial increase in peak aortic enhancement but not in peak hepatic enhancement.