Effect of Patient Characteristics, Including Cardiothoracic Ratio, on Vessel Enhancement in Coronary Computed Tomography Angiography

This retrospective study aimed to evaluate the effects of various patient characteristics, including cardiothoracic ratio (CTR), on vessel enhancement in coronary computed tomography (CT) angiography (CCTA). We screened the 306 patients who underwent CCTA with 80-detector row CT for clinical assessment due to suspected or confirmed coronary artery disease. The change in iodine dose per contrast enhancement (IDCE) (mgI/HU) was calculated as the product of 300 mgI multiplied by total body weight (TBW), divided by the change in Hounsfield unit (HU) obtained by subtracting the HU value. CTR was measured on CT images in scout view. Subsequently, we conducted linear regression analyses among age, sex, body size, CTR, heart rate, scan length, and scan start on IDCE. To evaluate the effects of age, sex, BSA, heart rate, scan length, scan start, and CTR on the IDCE, we used multivariate regression analysis. A significant positive correlation was observed between coronary artery IDCE and patient age (r2 = 0.07, p < 0.01). Linear regression analysis revealed inverse correlations between coronary artery IDCE and height (r2 =  − 0.30), total body weight (r2 =  − 0.53), body mass index (r2 =  − 0.23), body surface area (BSA; r2 =  − 0.56), lean body weight (r2 =  − 0.50), scan length (r2 =  − 0.01), and CTR (r2 =  − 0.02). There was no significant correlation between coronary artery IDCE and heart rate (r2 = 0.00, p = 0.74) or scan start (r2 =  − 0.01, p = 0.10). Standardized regression coefficients showed that the effect of BSA (− 0.71) was greater than that of other variables (CTR − 0.14, scan start − 0.10). The results of this study showed that patient BSA, CTR, and start scan significantly affect the IDCE of the coronary artery on CCTA images.