缩窄320排CT冠状动脉成像采集时间窗的可行性

Feasibility of narrowing acquisition time window of 320-slice CT coronary angiography

目的探讨缩窄320排CT冠状动脉CT血管成像(CCTA)采集时间窗的可行性。方法收集90例接受CCTA的疑似冠心病患者。根据CCTA图像质量评分结果获得血管和患者层面最佳时相,依照不同心率患者CCTA最佳时相预估其由舒张期转移至收缩期的临界心率,预估采集时间窗缩窄范围。比较预估缩窄时间窗后(缩窄时间窗组)与CT设备预设时相(预设时相组)的图像质量,以及预估缩窄时间窗前后辐射剂量的差异。结果患者层面CCTA最佳时相转移临界心率为70次/分。预估心率65~70次/分患者CCTA时间窗可缩窄为R-R间期72%~80%,心率70~95次/分患者可缩窄为R-R间期40%~50%。2组之间最佳血管时相和最佳患者时相图像质量差异均有统计学意义(P均<0.05)。预估缩窄时间窗前后有效辐射剂量差异有统计学意义(t=44.14,P<0.01),缩窄后辐射剂量降低约43%。结论对屏气后心率稳定(心率波动≤5次/分)患者行CCTA时,根据不同心率缩窄采集时间窗,可提高图像质量、降低辐射剂量。

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.