Objective: To assess whether tube voltages and contrast flow rates have an impact on a test bolus (TB)-based contrast-enhancement-prediction (CEP) algorithm during coronary computed tomographic angiography (CCTA). Materials and Methods: A total of 188 anonymized CCTA examinations following TB scans were collected. During TB, a tube voltage of 100 kV and contrast flow rate of 3.5 mL/s were applied for Group 1 and 120 kV and 4.5 mL/s for Group 2. True aortic enhancements were extracted with a region of interest at the ascending aorta (AAo). TB signals and group information were used as independent variables in a stepwise linear regression analysis to predict aortic enhancement. For each patient, the errors in predicted aortic enhancements were calculated. Results: Time to peak enhancement in the AAo (PT AAo) and peak enhancement in the descending aorta (PE DAo) during the TB study had significant correlations with AAo (AAo= -125.627+1.619×PE DAo+16.236×PT AAo r=0.782, p<0.001). The CEP algorithm without group information presented a minor systemic underestimation in Group 1 [-8 Hounsfield unit (HU)] and an overestimation in Group 2 (8 HU). Conclusion: The TB-based CEP of aortic enhancement is feasible. The tube voltages and contrast flow rates during TB scanning were statistically significant, but resulted in a clinical negligible impact on the CEP algorithm.