多层螺旋CT三维成像质量评估方法研究  

Study on the assessment method of 3D imaging quality of multi-slice spiral CT

作　　者：魏方圆 孙博洋 李爽 王超 王依 张斌 WEI Fang-yuan;SUN Boyang;LI Shuang(Medical Engineering Department,Beijing Daxing District People's Hospital,Beijing 102600,China.)

机构地区：[1]北京市大兴区人民医院医学工程部,北京102600 [2]北京市大兴区人民医院组织人事科,北京102600 [3]北京市大兴区人民医院放射科,北京102600

出　　处：《中国医学装备》2023年第2期30-34,共5页China Medical Equipment

摘　　要：目的:研究多层螺旋CT三维成像质量评估方法,提升CT三维成像的准确性,以保障CT影像的高质量。方法:通过简单指数衰减频率,计算X射线在穿透人体过程中散射与反射的穿透效果,建立X射线衰减指数模型。通过直角坐标系扇形束,统计图像测量的组织密度,在CT的初始图像中获得图像噪声模型,并得到图像噪声信号以及通过滤波反投影重建的三维CT图像。以图像信噪比、空间分辨率、灰度值均匀性和重建时间作为评估指标,对CT三维成像质量进行评价。结果:所有图像序列下的信噪比均>2.5,空间分辨率分别>1.51 lp/mm和1.52 lp/mm,灰度值均匀性<20%,且重建时间远<25 s。结论:多层螺旋CT三维成像质量评估方法具备实用性,能够保证得到有效的图像质量评估结果,提高CT三维成像的准确性。Objective: To study the assessment method of three-dimensional(3D) imaging of multi-slice spiral computed tomography(CT) because the high quality CT images can help doctors to judge the disease more accurately and improve the accuracy of 3D imaging of CT. Methods: A simple exponential attenuation frequency was used to calculate the penetration effect of X-ray scattering and reflection in the process of penetrating human body, so as to construct X-ray attenuation exponential model. The flabellum of rectangular coordinate system was used to calculate the tissue density that was measured by image, and the noise model of images was obtained in the CT primary images.And then, the noise signal of images and the reconstructed 3D CT image by filter back projection were obtained. The signal-to-noise ratio of image, the spatial resolution, the homogeneity of gray value and reconstruction time were used as assessment indicators to evaluate the CT 3D imaging quality. Results: The signal-to-noise ratio of all image sequences was > 2.5, and the spatial resolution respectively was > 1.51 lp/mm and 1.52 lp/mm, and the homogeneity of gray value was < 20%, and the time of reconstruction was far less than 25 s. Conclusion: The assessment method of multi-slice spiral CT 3D imaging quality has practicability and it can obtain effective assessment results of image quality and can improve the accuracy of CT 3D imaging.

关 键 词：多层面螺旋CT 三维成像 成像质量评估 X射线衰减指数模型 灰度值均匀性 空间分辨率 

分 类 号：R816[医药卫生—放射医学]