双源CT低剂量适应性序列扫描对高心率冠状动脉成像的初步研究

Low-dose adaptive sequence scan of dual-source heart rate： an initial study

目的研究双源CT低剂量适应性序列扫描技术在高心率患者冠状动脉CTA的应用，并评价其图像质量。方法将72例心率70次／min（bpm）以上行冠状动脉CTA检查的患者按扫描方式分为2组。A组40例行适应性序列扫描。B组32例行常规回顾性心电门控螺旋扫描。对2组扫描的冠状动脉分别做图像处理，应用秩和检验比较2组患者冠状动脉段图像质量总体评分，应用两独立样本t检验比较2组患者辐射剂量。结果A组评价501段冠状动脉，B组评价400段冠状动脉。可评价的冠状动脉段图像质量评分平均秩次，A组为475．42，B组为420．41，2组间比较差异有统计学意义（Z=-3．509，P=0．000）。平均有效剂量A组为（6．2±0．9）mSv，B组为（14．7±1．9）mSv，2组间差异有统计学意义（t=-27．011，P=0．000）。结论适应性序列扫描对高心率患者冠状动脉CTA检查具有可行性，该技术能显著降低辐射剂量而保证诊断所需图像质量。

Objective To investigate the application of low-dose adaptive sequence scan of dualsource CT coronary angiography in patients with high heart rate and evaluate the image quality. Methods Seventy-two patients who underwent coronary CT angiography with heart rate 〉 70 bpm were divided into 2 groups. Group A was adaptive sequence scan, and Group B was retrospective ECG-gating helical scan. Examinations were performed on a dual-source CT scanner （Somatom Definition ）. All images were transferred to a workstation for further processing and analysis. The image quality was evaluated using same criteria. The image quality of coronary artery segments was compared in two groups using rank sum test, and the radiation dose was compared using t test. Results A total of 501 coronary artery segments were evaluated in group A and 400 segments in group B. The mean ranks in image quality of coronary artery segments in group A was 475.42, whereas 420. 41 in group B. There was a statistical difference in image quality between the two groups （ Z = - 3. 509, P = 0. 000 ）. The effective dose was on average （ 6. 2 ± 0. 9） mSv in group A, whereas on average （14. 7 ± 1.9 ） mSv in group B, there was a statistical difference between the two groups（t = -27.011, P = 0. 000）. Conclusions Adaptive sequence scan in dual-source CT coronary angiography is feasible in patients with high heart rates. This scan mode can substantially reduce radiation dose and maintain the diagnostic image quality.