Investigation of image quality and radiation dose of coronary CT angiography in a single cardiac cycle with different heart rate

Objective: To investigate the image quality and radiation dose of coronary computed tomography argiograply (CCTA) with wide-body detector CT in single cardiac cycle with different heart rate. Methods: A total of 821 patients with clinically suspected coronary artery lesions were performed CCTA examination continuously. They were divided into six groups:group A (< 65 bpm) with 132 cases, group B (66-75 bpm) with 244 cases, group C (76-85 bpm) with 145 cases, group D (86-95 bpm) with 101 cases, group E (96-105 bpm) with 101 cases and group F (106-135 bpm) with 98 cases. The CT values of the aorta root and the middle segment of LAD and RCA, the signal to noise ratios (SNRs), the contrast noise ratios (CNRs), the effective doses (E), the diagnostic rates and scores were compared among six groups of CCTA images. Results: There was no significant difference in objective quality between the six groups (P > 0.05). There was no significant difference in the diagnostic rates of LAD, LCX and RCA (all P > 0.05). However, there were significant differences in LAD, LCX and RCA with 4 points (excellent) among the six groups (x² = 27.614, 58.475, 39.571, P < 0.05). There were significant differences in radiation dose among the 6 groups (F = 37.32, P < 0.05). The radiation dose of group B was highest, and that of group D, group E and group F was the lowest. Conclusions The CCTA images with wide-body detector CT in single heart cycle with different heart rate can meet the clinical diagnostic requirements, but image quality declined with heart rate increasing. The higher heart rate groups (heart rate > 85 beats/min) had lower radiation doses. (authors)