Abstract: Objective　To investigate the image quality and radiation dose of computed tomography coronary angiography（CTCA） based on a 3rd generation dual-source SOMATOM Force CT（Force CT） and high-pitch Turbo Flash scan mode when being used in patients with different heart rate（HR）.Methods　A total of 98 patients who underwent CTCA at Zhejiang Hospital between August and November 2016 were selected for this study.The patients were divided into three groups according to the HR during the CTCA scan：A group（HR≤65 beats/min，47 cases），B group（65 beats/min<HR≤75 beats/min，24 cases），and C group（HR>75 beats/min，27 cases）．The patients in all three groups were scanned using Force CT and the high-pitch Turbo Flash scan mode.The image quality of various segments of the coronary artery in the three groups was scored subjectively.The dose-length product（DLP） and effective radiation dose（ED） of each group were recorded and compared.Results　The images of 1 443 coronary segments were obtained and evaluated.There were 1 291 segments（89.47%） that scored 1 point for image quality，149 segments（10.33%） had 2 point image quality，and 3 segments（0.20%） scored 3 points for image quality.Gender had no significant effect on HR，image quality，DLP and ED（P>0.05）．The average DLP of the patients was（51.3±12.8） mGy?cm and the average ED was（0.72±0.18） mSv.There were significant differences in the image quality，DLP，and ED among the three groups（P<0.05）．The image quality scores of the B and C groups were higher than the A group（P<0.05），while the DLP and ED of the C group were higher than the A and B groups（P<0.05）．Conclusion　The CTCA based on Force CT and the high-pitch Turbo Flash scan mode has clinical application value for patients with different HR，particularly for patients with HR≤65 beats/min.The appropriate acquisition phase is chosen according to the patient's HR and the images meeting diagnostic requirements can be obtained.Moreover，the effective radiation dose can be < 1 mSv.

Key words: Coronary angiography, Multidetector computed tomography, Turbo Flash scan mode, Image quality, Radiation dosage

摘要： 目的　基于第三代双源SOMATOM Force CT探讨不同心率患者在采用大螺距Turbo Flash扫描模式进行CT冠状动脉成像（CTCA）的图像质量和辐射剂量。方法　选取2016年8—11月于浙江医院行CTCA的98例患者，根据CTCA扫描时心率将其分为3组：心率≤65次/min为A组（47例），65次/min<心率≤75次/min为B组（24例），心率>75次/min为C组（27例）。3组均采用第三代双源SOMATOM Force CT大螺距Turbo Flash扫描模式进行扫描。对3组冠状动脉各个节段的图像质量进行主观评分，记录并比较3组的剂量长度乘积（DLP）和有效辐射剂量（ED）。结果　3组患者共出现1 443个冠状动脉节段，图像质量评分为1分的节段有1 291个（89.47%），2分的节段有149个（10.33%），3分的节段有3个（0.20%）。不同性别的心率、图像质量评分、DLP和ED比较，差异均无统计学意义（P>0.05）。患者DLP为（51.3±12.8）mGy?cm，ED为（0.72±0.18）mSv。3组图像质量评分、DLP和ED比较，差异均有统计学意义（P<0.05），其中，B、C组图像质量评分均高于A组（P<0.05）；C组DLP、ED均高于A组和B组（P<0.05）。结论　基于Force CT采用大螺距Turbo Flash扫描模式进行CTCA检查对于不同心率患者均有临床应用价值，尤其是心率≤65次/min，根据不同心率选择合适的采集时相，可以得到满足诊断要求的图像，且ED<1 mSv。

关键词: 冠状血管造影术, 多排探测器的计算机断层扫描, Turbo Flash扫描模式, 图像质量, 辐射剂量