ABSTRACT
PURPOSE: This study aimed at analyzing the relationship between the estimated volume of distribution on computed tomography (eVdCT) of non-ionic contrast medium and four different patients' body size parameters (BSPs) (total body weight, body mass index, body surface area, and lean body weight) in abdominal dynamic contrast-enhanced computed tomography (ADCE-CT) . Moreover, this study intended to derive a method for calculating the iodine dose to target contrast enhancement. METHODS: We measured enhanced CT values of the equilibrium phase of the abdominal aorta in 527 patients who underwent ADCE-CT. The eVdCT of the ADCE-CT equilibrium phase was calculated from enhanced CT values based on the pharmacokinetic model. The optimal iodine dose (OID) was calculated from the regression analysis of eVdCT and BSP. RESULTS: The eVdCT was 7741.1±1799.5 ml. The eVdCT showed a strong positive correlation with BSP and could be calculated using a linear regression equation. The correlation coefficients for total body weight, body surface area, and lean body weight were 0.83, 0.84, and 0.81, respectively. The OID per unit BSP required for target iodine concentration of the abdominal aorta on ADCE-CT (TIC) could be calculated as "OID [mgI/BSP]=[(aï½¥BSP+b)×TIC]/BSP". CONCLUSION: The OID calculation method based on the patients' body size parameters and estimated volume of distribution can normalize contrast enhancement in abdominal dynamic contrast-enhanced CT.
