O-MAR技术在头颈CT检查中去除口腔内金属伪影的应用评估

摘要

ObjectiveTo explore the effect of Orthopedic Metal Artifact Reduction (O-MAR) technique in reducing dental metallic artifacts in head and neck CT examination.Methods65 patients with dental titanium prosthesis were conducted head and neck CT angiography scan. The patients were selected from Jan. to Dec. in 2014 of our hospital. The images were reconstructed by two different algorithms of O-MAR technique (group A) and traditional technique (group B). The regions of interest were placed in bilateral masseter muscles. Two groups’ standard deviation of the regions of interest was measured with paired t-test and image quality was subjectively scored. The image quality scores and demonstration of the oral cavity were conducted between two doctors, and analyzed with rank sum test andχ2test.Results The results of two doctors’ image quality scores are: ipsilateral masseter (z=-6.06,P<0.05); contralateral masseter (z=-4.79,P<0.05), the difference is statistically significant. Image quality score in group A is higher than that of group B (χ2=34.03,P<0.05), the difference is statistically significant; The standard deviation results are ipsilateral masseter (t=-9.34,P<0.05) and contralateral masseter (t=-4.06,P<0.05), the difference is statistically significant. There is no significant difference of bilateral masseter standard deviation in group A (t=1.48,P>0.05), while the difference of bilateral masseter standard deviation in group B (t=5.38,P<0.05) is statistically significant.Conclusion O-MAR technique is superior in decreasing the effect of high atomic number artifacts on image quality, and provides valuable information for clinical diagnosis.%目的：探讨金属伪影去除技术（Orthopedic Metal Artifact Reduction，O­MAR）在头颈CT检查中去除口腔内金属伪影的效果。方法按照入选条件选取2014年1月～12月间在我院行头颈CT血管造影（Computed Tomographic Angiography，CTA）检查同时口腔内含有钛金属补牙材料植入物的患者65例，扫描后对图像分别进行O­MAR技术重建（A组）与常规技术重建（B组）。以双侧咬肌作为感兴趣区（Region­of­Interest，ROI），比较两组ROI的CT值标准差（Standard Deviation，SD），并对图像质量进行主观评分。采用配对t检验比较两组SD值；图像质量评分的比较采用配对资料的秩和检验和χ2检验。结果两位医师对两组图像质量评分结果：同侧咬肌（z=­6.06，P<0.05）；对侧咬肌（z=­4.79，P<0.05），差异具有统计学意义。且评分结果A组平均分较B组高（χ2=34.03，P<0.05），差异具有统计学意义；A、B两组图像测得的SD值结果：同侧咬肌（t=­9.34，P<0.05），对侧咬肌（t=­4.06，P<0.05），差异具有统计学意义；A组双侧咬肌测得的SD值结果（t=1.48，P>0.05）差异没有统计学意义，B组双侧咬肌测得的SD值结果（t=5.38，P<0.05）差异具有统计学意义。结论 O­MAR能有效减少高原子序数伪影对图像质量的影响，为临床诊断提供有价值的诊断信息。