宝石能谱CT在金属内固定及关节置换术后检查中价值

Value of gemstone spectral CT to the examination after metallic fixation and joint replacement

目的 探讨宝石能谱CT单能量成像技术在消除金属内固定及关节置换术后金属伪影中的临床应用价值。方法 行金属内固定术患者30例,关节置换术患者12例,于术后7d内行能谱CT扫描（gemstone spectral imaging,GSI）,应用后处理工作站中能谱分析软件（GSI Viewer）进行数据分析,从40KeV开始每隔10KeV进行重建,获得40~140keV共11种单能量图像。选择图像信噪比最高的单能量区进行重建,并应用金属伪影消除软件（metal artifacts reduction software,MRAS）进行处理,比较单能量、单能量＋MRAS图像质量。结果 数据分析结果显示,在120KeV单能量区图像信噪比最高;120KeV单能量图像质量评分0分2例（4.76%）,1分8例（19.05%）,2分22例（52.38%）,3分10例（23.81%）;120KeV单能量＋MRAS图像质量评分0分25例（59.52%）,1分16例（38.10%）,2分1例（2.38%）,3分0例（0）,120KeV单能量图像质量优于120KeV单能量＋MRAS,差异有统计学意义（P〈0.05）。结论 宝石能谱CT扫描可有效减少金属内固定及关节置换术后金属伪影和硬化束伪影,提高检查部位的CT图像质量,在不影响诊断条件的前提下,可尝试使用MARS技术,尽可能消除伪影。

Objective To evaluate the application value of gemstone spectral CT to reducing artifacts after metallic fixation and joint replacement. Methods Thirty patients undergoing metallic fixation and 12 patients undergoing joint replacement received gemstone spectral CT imaging scanning 7 days after operation. The gemstone spectral imaging （GSI） viewer in post-processing system was used to analyze the data to obtain 11 monoenergetic images ranging from 40 to 140 KeV by reconstructing at intervals of 10 KeV. The monoenergetic area with the highest image signal-noise ratio was chosen to reconstruct, and metal artifacts reduction software （MRAS） was used to process the data. The qualities of images were compared between monoenergetic image and monoenergetic plus MRAS images. Results The data analysis showed the image signal-noise ratio was the highest in the 120 KeV monoenergetic area, among which the quality grading score was0in2 cases （4.76%）, 1 in8 cases （19.05%）, 2 in 22 cases （52.38%）, and3 inl0 cases （23.81%）. Among 120 KeV monoenergetic＋ MRAS images, the quality grading score was 0 in 25 cases （59. 52%）, 1 in 16 cases （38.10%）, 2 in 1 case （2.38%）, and 3 in 0 case （0）, significantly better than the quality of 120 KeV monoenergetic images （P〈0.05）. Conclusion Gemstone spectral CT can effectively reduce the artifacts of metallic fixation and beam hardening artifacts, and improve the image quality. The MARS reconstruction should be applied individually, reducing the artifact under the premise of not affecting the diagnostic conditions.