低剂量、大螺距双源CT前瞻性心电门控冠状动脉成像在心房颤动患者中的初步应用

目的评价第二代双源CT大螺距前瞻性心电门控扫描模式（fllash spiral）在房颤患者中应用的可行性。方法从我院接受大螺距双源CT冠状动脉成像检查的1077例患者中，选择房颤患者10例，分别采用HP前瞻性心电门控扫描（flash spiral模式）和回顾性心电门控模式扫描（spiral模式）。Flash spiral模式采集图像时间选择为RR间期的20％-30％成像。结果10例患者均采用flash模式扫描，其中7例患者图像质量好（评分1分），3例患者有轻度伪影，但可评价血管（评分2分）。SpirM扫描中，4例病例右冠状动脉伪影重，为非诊断血管病例，1例回旋支重度伪影。Flash模式扫描有效射线剂量为O．680-1．887mSv，8例患者低于1mSv。Spiral扫描有效射线剂量为14．920-21．306mSv。结论①房颤患者采用大螺距flash spiral模式单个心动周期成像可获得良好的效果，且图像质量优于回顾性心电门控模式。②由于RR间期不规则，房颤患者flash spirM扫描时必须在下一个R波前完成扫描，需提前采集数据时间（RR间期的20％-30％采集为最佳）。③房颤患者flash spiral扫描有效射线剂量低于1mSv。

Application of low-dose, high-pitch spiral acquisition dual-source CT coronary angiography in patients with atrial fibrillation

Objective The objective was to attempted to investigate whether high-pitch spiral acquisitiondual-source CTCA can be performed in patients with atrial fibrillation at low dose. Methods Ten patients with AF who were admitted for a first diagnostic coronary angiogram were screened for participation. All patients underwent dual-source CT. Patients were performed CTCA using the prospectively ECG-gated high-pitch mode and retrospective ECG gating spiral acquisition respectively with their permissions. The start phase for image acquisition of the most cranial slice was selected at 20%-30% of the R-R interval in all patients. Results Image qualities of prospectively ECG-gated high-pitch mode were rated as being excellent in 7 cases of all the patients and only 3 cases image qualities were graded score2. By using retrospective ECG gating spiral acquisition mode. Non-diagnostic image quality （score3） occurred in 4 patients which were observed in RCA and 1 patient in LCX. The estimated radiation dose ranges from 0.680 to 1.887 mSv in flash mode and the radiation dose of spiral mode were very high ranging from 14.920 to 21.306 mSv. Conclusion Our case series suggest that patients with atrial fibrillation rhythm can be performed CTCA with high-pitch spiral acquisition mode. 20%-30% of the RR interval window for data acquisition for high-pitch dual＇source CTCA may probably obtain good image quality with low doses.