双能量CT单能谱成像技术在骨折金属固定术后的应用

Clinical application of monoenergetic technique of dual-energy CT in the fractures fixed with metal fixer

目的探讨双能量CT单能谱成像技术去除金属伪影用于骨折金属固定术后的临床应用价值。方法对45例骨折金属固定术后复查的患者使用双源CT双能量扫描，采用双能量扫捕程序，一次性扫描采集2个不同能量的数据。所得原始数据的后处理采用100及140kV2个不同能量的数据，用单能谱成像技术利用不同的能谱直接进行不同密度的金属减影。所得数据分别进行单能谱成像法（A法）和模拟常规法（B法）重组，包括MPR、VR和MIP。对2种成像方法的图像质量和伪影显示进行Wilcoxon符号秩和检验。结果南于采用双能量单能谱成像CT重组技术，图像伪影少，其中A法中图像质量为优者平均达91．9％（124／135），B法中图像质量为优者平均为59．3％（80／135），两组间图像质量差异有统计学意义（Z=-12．541，P〈0．01）；A法中无图像伪影者占89．6％（121／135），B法中仅占45．2％（61／135），两者间差异有统计学意义（Z=-11．910，P〈0．01）。结论双能量单能潜CT扫描技术能够有效去除金属伪影，清晰显示骨折金属固定术后的细微结构。

Objective To analyze the clinical application of monoenergetic technique of dual-energy CT in removing metal artifacts for patients with fractures fixed with metal fixer. Methods Forty-five patients with fractures fixed with metal fixer undetavent dual-energy CT scanning for the fractures. Two different data were collected in one-time scanning using dual-energy scanning sequence. With munoenergetic technique, two different data at 100 and 140 kilovolts were used for subtraction to removing metal artifacts based on different densities. Haw data were reconstructed with monoenergetie technique （group A） and conventional simulation method （group B） , respectively. And, all data were reconstructed with muhiplanar reconstruction （MPR）, volume rendering （VR） and maxinmm intensity projection （MIP）, respectively. Wilcoxon signed rank test was applied tor the comparison of imaging quality and artifacts between the two groups. Results There were fewer artifacts on the images due to the application of monoenergetic technique in dual-energy CT scanning. In group A, the rate of high-quality images reached to 91.9% （124/135） ; and, in group B, it was 59.3% （80/135） . There were statistical difference hetween the two gruups （Z = - 12. 541 , P 〈 0. 01）. The images without artitact reached to 89. 6% （121/135） in group A; whereas, it was 45.2% （ 61/135 ） in group B. There was statistical difference between the two groups （ Z = - 11.91 0, P 〈 0.01 ）. Conclusion Using munoenergetic technique, metal artifacts were removed effectively and the fine strueture of fracture was clearly displayed.