Abstract: Objective To analyze the feasibility of dual-low-dose coronary computed tomography angiography (CCTA) with low tube voltage and low contrast agents in the elderly patients. Methods This study consecutively enrolled the elderly patients who underwent CCTA examination in Geriatric Hospital of Nanjing Medical University from March 1, 2021 to August 31, 2021. The patients were randomly divided into two groups. Routine-dose group underwent routine-dose scanning with tube voltage of 100 kVp and contrast dose of 70 mL, and dual-low-dose group underwent dual-low-dose scanning with low tube voltage of 70 kVp and low contrast dose of 30 mL. The two groups were further divided into four subgroups according to whether the heart rate was >70 beats/min or whether the body mass index (BMI) was >25. The CCTA image quality and radiation dose were compared between the corresponding subgroups. Results The radiation dose in all subgroups of dual-low-dose group was significantly lower than that in the corresponding subgroup of routine-dose group(P<0.01). The coronary artery luminal CT value, image noise, signal-to-noise ratio, contrast-to-noise ratio and the overall subjective mean score of coronary artery showed no significant differences between the subgroups with BMI≤25 of dual-low-dose group and the corresponding subgroups of routine-dose group(P＞0.05). The coronary artery luminal CT value and the overall subjective mean score of coronary artery showed no significant differences(P＞0.05), while image noise, signal-to-noise ratio, contrast-to-noise ratio showed significant differences between the subgroup with heart rate ≤70 beats/min,BMI＞25 of dual-low-dose group and the corresponding subgroup of routine-dose group(P＜0.01 or 0.05).All the subjective and objective image quality indicators showed significant differences between the subgroup with heart rate ＞70 beats/min,BMI＞25 of dual-low-dose group and the corresponding subgroup of routine-dose group(P＜0.01 or 0.05). Conclusions In the elderly, BMI shows obvious effects on the image quality of dual-low-dose CCTA examination. The elderly patients with BMI ≤ 25 are suitable for dual-low-dose CCTA examination with low tube voltage and low contrast agents.

Key words: angiography, coronary artery disease, radiation dosage, contrast medium, aged