目的探讨Flash CT双能扫描单 能量成像技术消减脊柱钉棒植入物伪影 的最佳单能量成像值，提供满足临床评 估要求的最佳重建图像。方法 对48例 19组单能量、混合能量图像在脊椎骨窗 和软组织窗行5分法评价，不同组别间差 异用Kruskal-Wallis秩和检验分析，同 一能量上伪影最大与最小层面CT值差异 用配对t检验；253枚螺钉的实际直径与 各单能量上螺钉的宽度比较。结果 单能 量图像评分的秩次比混合能量图像高， 130keV的图像评分秩次最高；120keV以 下的单能量图像伪影最重层面与无伪影 层面的CT值差异明显，P＜0.05；单能量 154keV上钉子近似真实值。结论 130keV 以上的图像金属伪影明显减少，结合骨 窗和软组织窗图像质量评分，130keV图 像质量最佳； 154keV单能量图像最佳观 察螺钉形态。

Objective To evaluate the optimal energy of the monochromatic imaging with Flash CT dual energy scan in reducing spinal pedicle screw metallic artifacts, and find out the best reconstruction images for clinical evalution. Methods The 19 groups images were evaluted by 5 points in bone window and soft tissue window from 48 patients,and the Kruskal-Wallis was used for statistical analysis,and the differences of Max and Mini artifacts was compared using Paired t-test at the same groups. The actual diameter of the 253 screws was compared with the width of each monochromatic images. Results The scores of monochromatic images were higher than the polychromatic images, and the 130keV image was the highest score.The heaviest and little artifacts CT value were large different below the 120keV Monochromatic images, of P＜0.05. Approximate true values of nails on 154keV monochromatic images. Conclusion Above 130keV monochromatic images reduced the metallic artifacts,but combined with the score of bone and soft tissue window, 130keV images was the best. The screw were best observed in the 154keV monochromatic images.