Wang Junqiang, Wang Yu, Zhu Gang, Chen Xiangqian, Zhao Xiangrui, Qiao Huiting, Fan Yubo
School of Biological Science and Medical Engineering, Beihang University, China.
Beijing Jishuitan Hospital, China.
Int J Med Robot. 2018 Jun;14(3):e1898. doi: 10.1002/rcs.1898. Epub 2018 Mar 30.
Spatial positioning accuracy is a key issue in a computer-assisted orthopaedic surgery (CAOS) system. Since intraoperative fluoroscopic images are one of the most important input data to the CAOS system, the quality of these images should have a significant influence on the accuracy of the CAOS system. But the regularities and mechanism of the influence of the quality of intraoperative images on the accuracy of a CAOS system have yet to be studied.
Two typical spatial positioning methods - a C-arm calibration-based method and a bi-planar positioning method - are used to study the influence of different image quality parameters, such as resolution, distortion, contrast and signal-to-noise ratio, on positioning accuracy. The error propagation rules of image error in different spatial positioning methods are analyzed by the Monte Carlo method.
Correlation analysis showed that resolution and distortion had a significant influence on spatial positioning accuracy. In addition the C-arm calibration-based method was more sensitive to image distortion, while the bi-planar positioning method was more susceptible to image resolution. The image contrast and signal-to-noise ratio have no significant influence on the spatial positioning accuracy. The result of Monte Carlo analysis proved that generally the bi-planar positioning method was more sensitive to image quality than the C-arm calibration-based method.
The quality of intraoperative fluoroscopic images is a key issue in the spatial positioning accuracy of a CAOS system. Although the 2 typical positioning methods have very similar mathematical principles, they showed different sensitivities to different image quality parameters. The result of this research may help to create a realistic standard for intraoperative fluoroscopic images for CAOS systems.
空间定位精度是计算机辅助骨科手术（CAOS）系统中的一个关键问题。由于术中透视图像是CAOS系统最重要的输入数据之一，这些图像的质量应会对CAOS系统的精度产生重大影响。但术中图像质量对CAOS系统精度的影响规律及机制尚未得到研究。
采用两种典型的空间定位方法——基于C形臂校准的方法和双平面定位方法——来研究不同图像质量参数，如分辨率、失真、对比度和信噪比，对定位精度的影响。通过蒙特卡洛方法分析不同空间定位方法中图像误差的误差传播规律。
相关性分析表明，分辨率和失真对空间定位精度有显著影响。此外，基于C形臂校准的方法对图像失真更敏感，而双平面定位方法对图像分辨率更敏感。图像对比度和信噪比对空间定位精度无显著影响。蒙特卡洛分析结果证明，一般来说，双平面定位方法比基于C形臂校准的方法对图像质量更敏感。
术中透视图像质量是CAOS系统空间定位精度的一个关键问题。尽管这两种典型定位方法具有非常相似的数学原理，但它们对不同图像质量参数表现出不同的敏感性。本研究结果可能有助于为CAOS系统创建术中透视图像的现实标准。
