目的 探讨低管电流联合窄窗、 迭代重建技术在降低冠状动脉CT血管成 像辐射剂量中的价值。方法 将80例怀疑 冠心病患者随机分为A、B两组，每组40 例，行CCTA，A组扫描管电压为120kV、管 电流为智能毫安，扫描窗为心动周期的 30%-80%；B组扫描管电压为120kV、管电 流为智能毫安的75%，扫描窗为心动周期 的70%-80%。对A组进行滤波反投影法重 建(filtered back projection，FBP)和 迭代重建(iterative reconstruction， IR)得到AF和AI两组，B组进行IR重建，比 较3组图像的噪声、信噪比(SNR)、主观 图像质量(评分)及辐射剂量(effective dose，ED)。结果 AI、B、AF组噪声依次 升高，SNR依次降低，AF组与AI、B间的噪 声及SNR差异均有统计学意义(P<0.05)； 主观图像质量评价，AI组优于其他两组 (P<0.05)，AF组最差，AF与B组差异无统 计学意义(P＞0.05)；A、B两组ED分别为 (3.40±1.34)mSv、(1.26±0.61)mSv，有 统计学差异(P＜0.05)。结论 在不降低冠 状动脉成像质量的情况下，低管电流联合 窄窗、迭代重建技术能降低CCTA的辐射剂 量。

Objective To investigate the value of low tube current combined with narrow window and iterative reconstruction in reducing radiation dose of coronary CT angiography. Methods 80 patients with suspected coronary heart disease were randomly divided into two groups: group A and group B, 40 patients in each group were treated with CCTA. Group A had 120 kV scan tube voltage, intelligent milliampere tube current and scan window 30%-80% of cardiac cycle. Group B had 120 kV scan tube voltage, 75% of intelligent milliampere tube current and scan window 70%-80% of cardiac cycle. Group A was reconstructed by filtering back projection (FBP) and iterative reconstruction (IR) to obtain AF and AI. Group B was reconstructed by IR. The noise, signal-to-noise ratio (SNR), subjective image quality (score) and radiation dose (ED) of the three groups were compared. Results Noise in AI, B and AF groups increased and SNR decreased in turn. There was statistical significance in noise and SNR between AF group and AI and B group (P<0.05). Subjective image quality evaluation showed that AI group was better than other two groups (P<0.05), AF group was the worst, and there was no statistical significance between AF group and B group (P>0.05). EDs in A and B groups were (3.40±1.34) mSv and (1.26±0.61) mSv, respectively, with statistical difference (P<0.05). Conclusion Low tube current combined with narrow window and iterative reconstruction can reduce the radiation dose of CCTA without reducing the quality of coronary artery imaging.