膝关节5个屈曲角度动态三维MR扫描在运动轨迹模拟中的应用

Application of MRI Scan with Five Intervallic Knee Flexion Angles on Quasi Dynamic Three-dimensional Knee Trajectory Simulation

目的目前有关高度屈膝位扫描方法的报道较少,故尚未能利用MRI图像构建完整屈伸膝过程中的膝关节运动轨迹。本文利用膝关节5个屈曲角度获得动态MRI图像,构建膝关节从过伸位到最大屈膝角度活动过程中的三维图像及准动态运动轨迹。资料与方法回顾性分析2015年9月-11月公开招募的10例健康成年志愿者,受试者取侧卧位,受试侧下肢在下,对侧下肢在上并尽量远离受试侧。膝关节以过伸位、屈膝30°位、屈膝60°位、屈膝90°位、最大屈膝角度位5个角度采集MRI图像。采用三维多回波恢复梯度回波序列,常规行矢状位抑脂扫描。扫描后将5个屈膝角度MRI图像DICOM格式数据分别导入软件进行分割、三维重建及注册后,通过插值计算法模拟完整屈伸膝过程中的运动轨迹。结果通过多屈膝角度MRI技术,获得5个屈膝角度的膝关节MRI图像。采用膝关节5个屈曲角度的MRI图像可重建从过伸位到最大屈膝角度活动过程中膝关节的三维图像及运动轨迹。结论膝关节5个屈曲角度MRI技术能直观地清晰显示膝关节解剖结构及运动轨迹,利用该模型可以对膝关节进行动态生物力学分析,具有良好的研究及临床应用价值。

Purpose Currently, there is rare study on knee flexion, thus the knee trajectory simulation in extension and flexion of the knee using MRI is not completed. This paper aims to establish Quasi dynamic three-dimensional（3D） knee trajectories which are simulated by MRI in five intervallic knee flexion angles. Materials and Methods Sagittal 3D multi-echo recovery gradient echo（MERGE） sequences of knees of ten healthy volunteers from September to November 2015 were acquired on a 3.0T magnet in five intervallic knee flexion angles-hyperextension, 30° flexion, 60° flexion, 90° flexion and maximum flexion. After bone and cartilage segmentation, 3D-reconstruction and 3D-registration, quasi dynamic 3D knee trajectories were simulated by using spine interpolation algorithm. Results All knee MRI of 10 volunteers were acquired by applying this technique and quasi dynamic 3D knee trajectories were simulated afterwards. Conclusion MRI scans in five intervallic knee flexion angles can clearly display the anatomic structure and quasi dynamic 3D trajectories simulation in knee joint, and can be well applied not only in basic but in clinic research.