Advanced template matching method for estimation of intervertebral kinematics of lumbar spine
Advanced template matching method for estimation of intervertebral kinematics of lumbar spine
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DOI：
10.1016/j.medengphy.2011.06.009
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发表时间：
2011-12-01
影响因子：
2.2
通讯作者：
Allen, R.
中科院分区：
文献类型：
--
作者：
Cerciello, T.;Romano, M.;Allen, R.
下背痛和其他退行性脊柱病变的诊断可能非常困难，到目前为止，还没有公认的标准。一般来说，这种病理与脊柱机械性能的改变有关，特别是与脊柱运动的不稳定性有关。椎间运动学可以是一种有价值的，客观的方法来评估脊柱节段的功能。透视成像系统可以在患者运动过程中以可接受的低X射线剂量提供腰束的连续筛查。椎间运动学的估计依赖于在整个荧光透视序列中对椎骨位置的准确识别：通过手动选择或自动方法识别和跟踪特定椎骨特征。本研究提出了一种新的椎体跟踪方法，基于图像模板匹配的椎体轮廓的精确椎间运动学分析。利用图像梯度算子获得椎体轮廓：它在边缘保持平滑滤波器之后操作，该滤波器旨在减少低剂量X射线图像噪声。一旦为每个椎骨定义了模板，就可用于确定整个荧光透视序列中每个图像中的最佳椎骨位置。所提出的方法的准确性进行了测试，使用图像的校准模型。椎间角度的平均误差约为0.4度，椎间旋转中心的平均误差约为2 mm。对进行被动屈伸运动的健康志愿者的五个腰椎透视序列进行处理。通过估计测量误差，将椎间运动学与其他方法（自动和手动）进行比较。结果表明，目前的方法提供了一个更好的表示随时间的运动参数的演变。特别是，当前方法与由经验丰富且经过培训的临床医生执行的手动选择程序之间的均方根差异导致椎间角度为1.3度，椎间轨迹为0.9 mm。该方法提供了一种有效的，自动化和客观的技术估计腰椎椎间运动学。(C)2011年IPEM。由爱思唯尔有限公司出版。保留所有权利。
Diagnosis of low back pain and other degenerative spinal pathologies can be extremely difficult and, so far, there are not accepted standards. In general, such pathologies are associated with alteration of mechanical properties of spine and, in particular, with the instability of spinal motion. Intervertebral kinematics can be a valuable, objective method to assess the functionality of spinal segments. Fluoroscopic imaging system can provide continuous screening of lumbar tracts during patient's motion, with an acceptable low X-ray dose. Estimation of intervertebral kinematics relies on accurate recognition of vertebrae positions throughout the fluoroscopic sequence: specific vertebrae features are identified and tracked either by manual selection or by automated methods. This study presents a new method of vertebra tracking, based on image template matching of the contour of the vertebral body for an accurate intervertebral kinematics analysis. An image gradient operator was utilized to obtain the vertebral contours: it operates after an edge-preserving smoothing filter designed to reduce low dose X-ray image noise. Once a template is defined for each vertebra, this is used to determine the best vertebral location in each image throughout the fluoroscopic sequence. Accuracy of the proposed method was tested using images of a calibration model. Average error achieved for the intervertebral angle is of the order of 0.4 degrees and approximately 2 mm for the intervertebral centre of rotation. Five fluoroscopic lumbar sequences of healthy volunteers undergoing passive flexion extension motion were processed. The intervertebral kinematics was compared with other methods (automated and manual) by an estimation of measurement error. Results showed that the current method provides a better representation of the evolution over time of kinematic parameters. In particular, root mean square differences between the current method and a manual selection procedure performed by an experienced and trained clinician resulted 1.3 degrees for the intervertebral angles and 0.9 mm for the intervertebral trajectory. The proposed method provides an effective, automated and objective technique for estimation of intervertebral kinematics of lumbar spine. (C) 2011 IPEM. Published by Elsevier Ltd. All rights reserved.