Feasibility of using orthogonal fluoroscopic images to measure in vivo joint kinematics
Feasibility of using orthogonal fluoroscopic images to measure in vivo joint kinematics
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DOI：
10.1115/1.1691448
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发表时间：
2004-04-01
影响因子：
1.7
通讯作者：
DeFrate, LE
中科院分区：
文献类型：
--
作者：
Li, GA;Wuerz, TH;DeFrate, LE
准确确定在体膝关节运动学仍然是生物医学工程中的一个挑战。本文提出了一种成像技术，使用两个正交的图像来测量6度的自由度（DOF）的膝关节运动学在负重屈曲。使用这种技术，在负重屈曲过程中，使用3-D荧光镜以不同屈曲角度捕获膝关节的正交图像。两个正交图像唯一表征了特定屈曲角度下的膝关节位置。然后在实体建模软件中创建虚拟荧光镜，并用于在实际成像过程中再现3D荧光镜的正交图像和X射线源的相对位置。软件中的两个虚拟相机用于表示X射线源。然后将膝关节的三维计算机模型引入虚拟荧光镜中，并通过两个虚拟摄像机投影到正交图像上。通过将膝关节模型的投影与在负重屈曲期间获得的膝关节的正交图像进行匹配，确定了6个自由度的膝关节运动学。使用具有已知位置和方向的规则形状的对象，该技术被证明具有0.1 mm和0.1度的精度，分别确定对象的位置和方向。
Accurately determining in vivo knee kinematics is still a challenge in biomedical engineering. This paper presents an imaging technique using two orthogonal images to measure 6 degree-of-freedom (DOF) knee kinematics during weight-bearing flexion. Using this technique, orthogonal images of the knee were captured using a 3-D fluoroscope at different flexion angles during weight-bearing flexion. The two orthogonal images uniquely characterized the knee Position at the specific flexion angle. A virtual fluoroscope was then created in solid modeling software and was used to reproduce the relative positions of the orthogonal images and X-ray sources of the 3-D fluoroscope during the actual imaging procedure. Two virtual cameras in the software were used to represent the X-ray sources. The 3-D computer model of the knee was then introduced into the virtual fluoroscope and was projected onto the orthogonal images by the two virtual cameras. By matching the projections of the knee model to the orthogonal images of the knee obtained during weight-bearing flexion, the knee kinematics in 6 DOF were determined. Using regularly shaped objects with known positions and orientations, this technique was shown to have an accuracy, of 0.1 mm and 0.1 deg in determining the positions and orientations of the objects, respectively.