Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 12 Sandy Bay Rd, Pokfulam, Hong Kong.
Spine J. 2013 Jun;13(6):697-705. doi: 10.1016/j.spinee.2013.02.061. Epub 2013 Apr 23.
Diffusion tensor fiber tractography is an emerging tool for the visualization of spinal cord microstructure. However, there are few quantitative analyses of the damage in the nerve fiber tracts of the myelopathic spinal cord.
The aim of this study was to develop a quantitative approach for fiber tractography analysis in cervical spondylotic myelopathy (CSM).
STUDY DESIGN/SETTING: Prospective study on a series of patients.
A total of 22 volunteers were recruited with informed consent, including 15 healthy subjects and 7 CSM patients. The clinical severity of CSM was evaluated using modified Japanese Orthopedic Association (JOA) score. The microstructure of myelopathic cervical cord was analyzed using diffusion tensor imaging. Diffusion tensor imaging was performed with a 3.0-T magnetic resonance imaging scanner using pulsed gradient, spin-echo, echo-planar imaging sequence. Fiber tractography was generated via TrackVis with fractional anisotropy threshold set at 0.2 and angle threshold at 40°. Region of interest (ROI) was defined to cover C4 level only or the whole-length cervical spinal cord from C1 to C7 for analysis. The length and density of tracked nerve bundles were measured for comparison between healthy subjects and CSM patients.
The length of tracked nerve bundles significantly shortened in CSM patients compared with healthy subjects (healthy: 6.85-77.90 mm, CSM: 0.68-62.53 mm). The density of the tracked nerve bundles was also lower in CSM patients (healthy: 086±0.03, CSM: 0.80±0.06, p<.05). Although the definition of ROI covering C4 only or whole cervical cord appeared not to affect the trend of the disparity between healthy and myelopathic cervical cords, the density of the tracked nerve bundle through whole myelopathic cords was in an association with the modified JOA score in CSM cases (r=0.949, p=.015), yet not found with ROI at C4 only (r=0.316, p=.684).
The quantitative analysis of fiber tractography is a reliable approach to detect cervical spondylotic myelopathic lesions compared with healthy spinal cords. It could be employed to delineate the severity of CSM.
弥散张量纤维束追踪是一种新兴的脊髓微观结构可视化工具。然而，对于脊髓型颈椎病（CSM）神经纤维束的损伤，目前还很少进行定量分析。
本研究旨在开发一种用于颈椎脊髓病（CSM）纤维束追踪分析的定量方法。
研究设计/设置：一系列患者的前瞻性研究。
共招募了 22 名志愿者，均签署了知情同意书，包括 15 名健康受试者和 7 名 CSM 患者。CSM 的临床严重程度采用改良日本矫形协会（JOA）评分进行评估。使用弥散张量成像对脊髓型颈椎病的脊髓微观结构进行分析。弥散张量成像采用 3.0T 磁共振成像扫描仪，采用脉冲梯度、自旋回波、回波平面成像序列。通过 TrackVis 生成纤维束，各向异性分数阈值设定为 0.2，角度阈值设定为 40°。ROI 定义为仅覆盖 C4 水平或从 C1 到 C7 的整个颈椎脊髓进行分析。比较健康受试者和 CSM 患者之间跟踪神经束的长度和密度。
与健康受试者相比，CSM 患者跟踪的神经束长度明显缩短（健康受试者：6.85-77.90mm，CSM 患者：0.68-62.53mm）。CSM 患者跟踪的神经束密度也较低（健康受试者：0.86±0.03，CSM 患者：0.80±0.06，p<.05）。尽管仅覆盖 C4 或整个颈椎脊髓的 ROI 定义似乎并不影响健康和脊髓型颈椎病脊髓之间差异的趋势，但在 CSM 病例中，通过整个脊髓型颈椎病的跟踪神经束密度与改良的 JOA 评分相关（r=0.949，p=.015），而在仅覆盖 C4 的 ROI 中未发现相关（r=0.316，p=.684）。
与健康脊髓相比，纤维束追踪的定量分析是一种可靠的方法，可用于检测颈椎脊髓病病变。它可以用来描绘 CSM 的严重程度。
