Optimization of Personalized Contrast Agent Injection Protocols Based on High Heart Rate: A Study Aimed at Enhancing Coronary CTA Image Quality

Objective Using wide-detector CT (WDCT), this study examines the effect of integrating heart rate into a P3T-based personalized contrast agent injection protocol on CCTA image quality in patients with high heart rates (HR ≥ 90 bpm), and further validates the clinical efficacy of the modified protocol. Methods This retrospective study included 160 patients who underwent WDCT coronary CTA from January to July 2024. Patients were divided into a low-HR group (heart rate < 90 bpm, n = 79) and a high-HR group (heart rate ≥ 90 bpm, n = 81). Image reconstruction utilized the SSF2 motion-correction algorithm after prospective ECG-gated acquisition. The contrast protocol was based on the P3T technique, considering the patient's BMI and tube voltage. Coronary image quality was evaluated through objective metrics (luminal attenuation, CNR, SNR) and a 5-point Likert scale. In an independent validation cohort (August–December 2024; n = 80; HR ≥ 90 bpm), the injection rate and volume for patients with a high heart rate were proportionally adjusted based on the reduction in CT attenuation to validate the effectiveness of the modified protocol. Result In the Primary Cohort, the conventional P3T protocol led to a 9.7%–16.3% reduction in coronary CT attenuation in the high-HR group compared to the low-HR group, along with significant decreases in CNR and SNR. After implementing the modified protocol in the validation cohort, CT attenuation and CNR for all coronary branches matched those of the low-HR group (all P > 0.05) and were significantly better than the conventional high-HR group (all P < 0.01). No significant differences were found in SVC or RA CT attenuation or CNR among the groups (P > 0.05), with no new venous artefacts detected. Subjective image quality was rated diagnostic (scores 4–5) across all groups, with no significant differences (P > 0.05) and excellent interobserver agreement (ICC > 0.80). Conclusion Using wide-detector CT and the SSF2 motion-correction algorithm, the heart-rate–integrated P3T personalized injection protocol improves coronary opacification and diagnostic confidence in high-heart-rate patients, without increasing artefacts in the superior vena cava or right atrium. This facilitates broader use of CCTA in these populations.