Influence of saline flushing on the optimal temporal window for CT of the liver using a time-density analysis

The purpose of this study was to evaluate the influence of saline flushing on the optimal temporal window for hepatic CT by analyzing time-density curves. Eighty-eight patients were randomly assigned to three groups to receive 100 mL of contrast material alone (n=32; group A), 100 mL of contrast material with 30 mL of saline flush (n=26; group B), and 85 mL of contrast material with 30 mL of saline flush (n=30; group C). In each group, the time-density curves of the liver, portal vein, and aorta were obtained. The degree of mean peak enhancement (PE), mean time to peak (TTP), time to onset of the equilibrium phase (Teq), and time between aortic peak enhancement and onset of equilibrium phase (Ta-eq) were analyzed. The PE of liver and portal vein for group B were significantly greater than those of group A (p<0.05). There was no significant difference in PE of liver, portal vein, and aorta, and TTP of liver and aorta between group A and group C. However, Teq and Ta-eq for group C were significantly shorter than those of group A and group B (p<0.0001). Using a saline flush was able to reduce iodine dose, however, when using the decreased contrast material with saline flush, the duration of the optimal temporal window for hepatic CT was shortened. (author)