双X线透视成像系统进行颈椎在体运动研究方法学的探索

Dual fluoroscopic image study on in vivo kinematics of cervical spine

目的观察应用双X线透视成像系统在颈椎在体运动学研究中下颌骨对颈椎图像的干扰度,探索颈椎在体运动学最佳位置的透视方法,为颈椎在体运动学研究提供方法学的可行性论证。方法应用双X线透视成像系统分别在两个C型臂夹角呈正交(90°)位、60°位及45°位采集健康志愿者5名(男4名,女1名)颈椎双平面X线图像,包括中立位、前屈后伸位、左右旋转位、左右侧屈位,比较各个不同位置时下颌骨对颈椎椎体图像的遮挡;采用下颌角对颈椎的干扰程度来作为评价的标准,通过对各个不同位置时下颌骨对颈椎图像干扰程度的评分,筛选最佳角度的透视方法。在做颈椎左右旋转运动透视时,比较躯干固定-头颅旋转模式和头颅固定-躯干旋转模式下下颌骨对颈椎图像的干扰程度,分别采集两种模式下的透视图像。结果 90°、60°和45°位时中立位、前屈后伸位、左右侧屈位、左右旋位透视下颌骨对颈椎图像干扰度均存在显著性差异(P<0.05)。45°位在上述位置时干扰度最小。在相同角度60°位,躯干固定-头颅旋转组与头颅固定-躯干旋转组相比有显著性差异(P<0.05)。结论颈椎在体运动学研究中应用双X线透视成像系统在交角45°位时可以最大限度的减少下颌骨的阻挡,坐位同轴躯干旋转代替头颅旋转可以减少下颌骨的干扰度,基本满足双X线成像系统二维-三维图像的匹配条件。

Objective To observe the obstacle of mandible to the cervical spine with the aid of dual fluoroscopic imaging system,explore the optimal perspective methods of in vivo kinematics of cervical spine,and verify the feasibility of cervical in vivo kinematic researches.Methods A dual fluoroscopic imaging system composed of two C-arms placed in different angles was utilized.X ray images of the cervical spine for five healthy volunteers（4 male,1 female） with standing,flexion-extension,twisting and bending positions were obtained with the C-arms in the angle of 90°,60°and 45°,respectively.The obstacles of mandible to the cervical spine in different positions were compared and the obstacle degree of mandible to the cervical spine was evaluated to screen the optimal perspective methods.The perspective images under conventional head rotation and coaxial trunk rotation were collected during cervical twisting to compare the obstacle of mandible to cervical images.Results There were significant differences in mandibular obstacle degrees among the three angles measured in standing,flexion-extension,twisting and bending positions（P〈0.05）.With two C-arms in 45°,the cervical spine was best imaged with the least obstacle.With two C-arms in 60°,significant differences could be found between the coaxial trunk rotation and the head rotation group.Conclusions For in vivo kinematics study of cervical spine,the obstacle of mandible to the cervical spine can be minimized with C-arms of dual fluoroscopic imaging system in 45°,and the coaxial trunk rotation can decrease the mandibular obstacle degrees as compared with the head rotation,which satisfy the requirement of 2D-3D image matching.