ISSN 1004-4140
CN 11-3017/P

义齿材质对CT图像伪影的影响:模体实验

Effect of denture materials on CT image artifacts: phantom experiment

  • 摘要: 目的:基于模体实验,优化多材质义齿伪影,为临床提供指导。方法:在CIRS模体中心依次放置空白对照及6种不同材质的义齿全冠模型,使用能量CT行双能量扫描,重建空白对照最佳对比度图像作基准,其余6组数据分别重建标准算法和骨算法下的最佳对比度图像及70~140 keV间隔10 keV的单能图像。记录CT值、SD值,计算伪影指数(AI)。行常规扫描,记录常规组与能量组的辐射剂量。由2名放射科医师对各组图像行主观评价,数据分析行方差分析或非参数检验。结果:能量组辐射剂量(6.15±0.10)mGy显著低于常规组(30.35±0.02)mGy。主观图像评分一致性良好,能量组图像质量随能级的提高而改善,伪影指数降低。标准算法:除上脂外,其余模块的AI值均对处理显著;除轻骨外,其余模块的AI值均因义齿材质不同而存在差异。骨算法:各模块的AI均对处理显著;脂肪、肌肉的AI值均因义齿材质不同而存在显著差异。结论:能量CT显著降低辐射剂量,纯钛材质义齿伪影最少,是临床全冠首选材质。能量CT结合虚拟单能成像可减少伪影,优化图像质量。临床观骨组织时推荐:纯钛140 keV;钴铬90 keV;钴铬烤瓷140 keV;镍铬120 keV;镍铬烤瓷120 keV;全瓷140 keV。

     

    Abstract: Objective: Based on phantom experiments, this study aims to optimize artifacts in multimaterial dentures and provide guidance for clinical practice. Method: A blank control and six denture full-crown models of different materials are placed sequentially at the CIRS phantom center. Subsequently, dual-energy CT scanning is performed using energy CT, and the optimal contrast image of the blank control is reconstructed as a baseline. Next, the optimal contrast images are reconstructed under standard and bone algorithms for the six groups, in addition to virtual monochromatic images at 70–140 keV with an interval of 10 keV. CT and SD values are recorded, and the artifact index (AI) is calculated. Routine scanning is performed and radiation doses of the routine and energy groups are recorded. Two radiologists subjectively evaluate the images of each group and perform a variance analysis or nonparametric tests for data analysis. Results: The radiation dose of the energy group (6.15±0.10) mGy is significantly lower than that of the routine group (30.35±0.02) mGy. The consistency of the subjective image scoring is favorable. As the energy levels increase, the image quality of the energy group improves, whereas the AI decreases. Standard algorithm: The AI values of all modules except the upper fat differ significantly. The AI values of all modules except the light bone differ significantly because of the different denture materials used. Bone algorithm: The AI values of all modules differ significantly, and the AI values of fat and muscle differ significantly owing to the different denture materials. Conclusion: Energy CT significantly reduces the radiation dose. Additionally, pure-titanium dentures have the least number of artifacts and are the preferred material for clinical full crowns. Energy CT combined with virtual single-energy imaging can reduce artifacts and optimize image quality. Recommendations for clinical observation of bone tissue are as follows: Pure titanium, 140 keV; cobalt–chromium, 90 keV; cobalt–chromium porcelain, 140 keV; nickel–chromium, 120keV; nickel–chromium porcelain, 120 keV; and all ceramic, 140 keV.

     

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