Study design and participants
CAD
CORONARY ARTERY DISEASE, CAD
As illustrated in Figure Flowchart of the study design. CAD, coronary artery disease; CCTA, coronary computed tomography angiography.Radiation and Contrast medium dose parameters.This prospective study received ethical approval from the Institutional Ethics Committee. Patients scheduled for CCTA from February to December 2022 due to suspected or known CAD were enrolled in this study, who were first categorized by body weight and then randomly assigned to one of the corresponding subgroups. Patients with implanted coronary stents were excluded because metal artifacts may be involved, which is important but a separate issue beyond dose and vessel enhancement as considered in the present study. Aside from the current study design, investigation on patients < 55  or > 85 kg was additionally carried out with a small number of cases, where the consideration on optimization might be different. Written informed consent was obtained from each participant before the CT examination.To test whether there was a potentially better setting than the current one, and if so, to determine which the optimal setting was for each group, the process of balancing as well as the priority placed on dose or image quality may vary from case to case. On image quality, it must be noted that the aim was not to evaluate if the resulting images were acceptable for clinical diagnosis but to investigate, with respect to those routinely accepted, the possibility and the associated cost for improvement, which raised the baseline for comparison.