RESUMO
Objective To observe image quality and impact factors for single heart beat coronary CTA (CCTA) with prospectively ECG-triggered CT in patients with low,high heart rate (HR) and arrhythmia.Methods Single heart-beat CCTA was performed for 208 patients with prospectively ECG-triggered 256-slice wide-detector CT without drug control of HR.The patients were divided into 3 groups,including low HR group (n=87,HR≤70 bpm),high HR group (n=38,HR＞70 bpm) and arrhythmia group (n=83,HR variation ＞ 10 bpm in 5 cardiac cycles).The normal reconstruction phase was set as 75％ or 45％ in R-R interval,while the optimal phase was that with the least motion artifacts.Univariate linear regression was used to analyze the impact factors for image quality.Results Compared with images of normal phase,the optimal phase of 105 patients (105/208,50.48％) was altered.In the optimal images,imaging quality,SNR and CNR were not significantly different among 3 groups (all P＞0.05).Image quality was significantly influenced by reconstruction phase and artifact type (both P＜0.001).Conclusion During prospectively ECG-triggered 256-slice wide-detector CCTA without drug control of HR,high HR and arrhythmia are not significant impact factors of image quality.