Effect of duration of contrast material injection on peak enhancement times and values of the aorta, main portal vein, and liver at dynamic MDCT with the dose of contrast medium tailored to patient weight

Aim To investigate the effects of contrast material injection duration on peak enhancement times and attenuation values of the aorta, main portal vein, and liver at MDCT when the dose of contrast material is adjusted to patient weight. Material and methods Seventy-five patients were randomly assigned to one of five groups, with durations of injection of 25, 30, 35, 40, or 45 s. All patients were injected with 2 ml/kg iodine (300 mg/ml). Attenuation values and peak enhancement times for the aorta, main portal vein, and liver were determined. The relationship between patient weight and enhancement times and values, the differences regarding peak enhancement times, and the relationship between injection duration and enhancement values were investigated using Pearson correlation, analysis of variance (ANOVA), and Spearman rank correlation, respectively. Results No significant correlations were seen between patient weight and peak enhancement times or values. Mean peak enhancement times for the aorta, main portal vein, and liver were 9–11 s, 18–22 s, and 30–34 s, respectively ( p  > 0.05). The correlations between injection duration and peak enhancement values were significant and negative. Conclusions Regardless of patient weight and injection duration, peak enhancement times of aorta, main portal vein and liver were approximately 10, 20, and 30 s, respectively. The enhancement values tended to be higher for shorter injection durations.