中文摘要：

目的 探讨能谱智能匹配技术联合自适应统计迭代重建（ASIR）在上腹部低对比剂量增强CT中的应用价值，并优化组合单能量水平及ASIR百分比。方法 将100例行上腹部增强CT的患者随机分为对照组（n=50）和试验组（n=50）。对照组采用120 kVp扫描，对比剂量450 mg I/kg，联合40% ASIR重建；试验组采用能谱智能匹配技术扫描，对比剂量300 mg I/kg，选取40～65 keV单能量图像（以5 keV为间隔）分别联合40%～60% ASIR（以10%为间隔）重建。对全部图像进行客观评价（肝脏、胰腺、腹主动脉和门静脉的CT值和对比噪声比，图像噪声）和主观评价，记录容积CT剂量指数（CTDIvol）。采用独立样本t检验比较客观评价和CTDIvol，采用Mann-Whitney U检验比较主观评分。结果 60 keV联合40% ASIR、55～60 keV联合50% ASIR的各图像质量指标均相当于或优于对照组。试验组CTDIvol与对照组相当。结论 应用能谱智能匹配技术联合ASIR，上腹部低对比剂量增强CT能谱扫描可以在不增加辐射剂量的条件下，获得优于120 kVp联合40% ASIR的图像质量。

英文摘要：

Objective To investigate the value of automatic spectral imaging mode selection and adaptive statistical iterative reconstruction （ ASIR） in upper abdominal enhanced CT with low contrast agent dose, and to optimize the combination of monochromatic energy level and ASIR percentage. Methods 100 patients underwent upper abdominal enhancement CT were randomly assigned into control group （n=50） and study group （n=50）. In the control group, tube voltage of 120 kVp and contrast medium of 450 mg I/kg were used with the images reconstructed using 40% ASIR. In the study group, CT spectral imaging with automatic spectral imaging mode selection and contrast medium of 300 mg I/kg were used, and monochromatic images （40-65 keV,intervals of 5 keV） were reconstructed using 40%-60% ASIR （intervals of 10%）, respectively. CT value, image noise and contrast-to-noise ratio of the liver, pancreas, aorta and portal vein and radiation dose were compared using two independent samples t test. Overall image quality was assessed by Mann-Whitney U test.Results All image quality indexes in 60 keV with 40% ASIR, 55-60 keV with 50% ASIR in the study group were equal to or better than the control group. There was no significant difference in radiation dose between control group and study group.Conclusion Combined automatic spectral imaging mode selection with ASIR, upper abdominal enhanced CT with low contrast agent dose could improve image quality compared to 120 kVp with 400/oo ASIR, without increasing radiation dose.