Feasibility of narrowing acquisition time window of 320-slice CT coronary angiography / 中国医学影像技术

ABSTRACT

Objective: To explore the feasibility of narrowing acquisition time window of 320-slice CT coronary angiography (CCTA). Methods: Totally 90 patients with suspected coronary heart disease who received CCTA were collected. The best time phase of blood vessels and patients were obtained according to image quality scores, and the critical heart rate from diastole to systole was observed according to the best time phase of CCTA in patients with different heart rates, then the range of narrowing acquisition time window was estimated. The image quality of estimated narrowing acquisition time window (narrowing time window group) and preset time phase with CT machine (preset time phase group), and the radiation dose before and after estimated narrowing acquisition time window were compared. Results: The critical heart rate of patients for CCTA optimal phase transfer was 70 bpm. In patients with heart rate of 65-70 bpm, CCTA acquisition time window could be narrowed to 72%-80% of R-R interval, while in patients with rate of 70-95 bpm could be narrowed to 40%-50% of R-R interval. Statistical differences were found in imaging quality of the best blood vessels time phase and the best patient time phase between 2 groups (all P<0.05). ED reduced by about 43% after estimated narrowing the acquisition time window (t=44.14, P<0.01). Conclusion: For patients with stable heart rate after breathholding (heart rate fluctuation ≤5 bpm), it is estimated that the acquisition time window of CCTA can be narrowed according to different heart rate, which can improve the image quality, and reduce the radiation dose.