AORTIC AND HEPATIC PEAK ENHANCEMENT AT CT - EFFECT OF CONTRAST-MEDIUMINJECTION RATE - PHARMACOKINETIC ANALYSIS AND EXPERIMENTAL PORCINE MODEL

PURPOSE: To investigate the effect of injection rate of contrast mediu m on aortic and hepatic peak enhancement at computed tomography. MATER IALS AND METHODS: Early pharmacokinetics of contrast enhancement was a nalyzed theoretically and simulated with a compartment model. Contrast enhancement curves were generated from the model at different injecti on rates (0.5-10.0 mL/sec). Time-enhancement curves were measured. The effect of contrast medium injection rate on the time and magnitude of peak enhancement was evaluated and validated empirically in pigs. RES ULTS: Theoretic predictions and experimental results were in good agre ement. Time to aortic peak enhancement was the sum of injection durati on and bolus transfer time of contrast medium from the injection site to the aorta. Time to hepatic peak enhancement was the sum of Injectio n duration and time to equilibrium. The magnitude of peak enhancement increased with the injection rate, but the increase was different in t he aorta and liver. CONCLUSION: Use of injection rates above 2 mL/sec did not substantially increase hepatic peak enhancement but helped inc rease the magnitude of arterial enhancement and temporal separation of arterial and venous phases of enhancement for dual-phase spiral CT.