Intravenous Contrast Material Administration at High-pitch Dual-source CT Coronary Angiography： Bolus-tracking Technique with Shortened Time of Respiratory Instruction Versus Test Bolus Technique

Objective To investigate the feasibility of acquiring the similar homogeneous enhancement using bolus-tracking techniques with shortened respiratory time in prospectively electrocardiogram-gated high-pitch spiral acquisition mode （Flash mode） coronary computed tomography angiography （CCTA） compared with test bolus technique. Methods One hundred and eighty-four consecutive patients with mean heart rate ≤65 beats per minute undergoing CCTA were prospectively included in this study. The patients were randomly divided into two groups. Patients in the group A （n=92） instructed to shorten respiratory time received CCTA using bolus-tracking technique with high-pitch spiral acquisition mode （Flash mode）, while those in the group B （n=92） underwent CCTA with test bolus technique. The attenuation in the ascending aorta, image noise, contrast-to-noise ratio and radiation doses of the two groups were assessed. Results There were no significant differences in the mean attenuation values in the ascending aorta （483.18±59.07 HU vs. 498.7±83.51 HU, P=0.183）, image noise （21.4±4.5 HU vs. 20.9±4.3 HU, P=0.414）, contrast-to-noise ratio （12.1±4.2 vs. 13.8±5.1, P=0.31） between the groups A and B. There were no significant differences in the radiation dose of dynamic monitoring scans （0.056±0.026 mSv vs. 0.062±0.018 mSv, P=0.068） and radiation dose of angiography （0.94±0.07 mSv vs. 0.96±0.15 mSv,P=0.926） between the two groups, while 15 mL less contrast material volume was administered in the group A than the group B. Conclusion Bolus-tracking technique with shortened time of respiratory in Flash mode of dual-source CT yields the similar homogeneous enhancement with less contrast material in comparison to the test bolus technique.