Abstract：Objective To determine the optimal automatic bolus tracking delay of coronary CTA by using high temporal resolution
wide-detector CT. Methods Nighty-one patients with suspected coronary heart disease underwent coronary CTA. The patients were
randomly divided into three groups based on different diagnostic delay (Td): Group A (n=30, Td=1.7 s), Group B (n=33, Td=3 s) and
Group C (n=28, Td=5 s). The images were assessed by 2 radiologists with experience of more than 5 years in CCTA. Results For
the root of ascending aorta and proximal sections of coronary arteries, the CT value of Group A and Group B were higher than that
of Group C. For distal sections, the CT value of Group B and C was higher than that of Group A. The ratios of distal and proximal
CT values were sorted as Group C, B and A from high to low. Subjective scores of Group B and C were higher than that of Group A.
Conclusion The enhancement of proximal and distal sections should be concidered when selecting the of automatic bolus tracking
delay in coronary CTA when using high temporal wide-detector CT.
