MRI在椎间盘平面和椎体平面测量颈脊髓值差异的比较

Diameters of cervical spinal cord at disc versus vertebral planes:MRI measurement

背景：颈脊髓的矢状径测量简单易行，能直接反映脊髓在椎管中状态，但目前对颈脊髓矢状径的测量多局限于椎体平面，椎间盘平面的测量较少见。目的：通过MRI分别对颈椎椎间盘平面和椎体平面的脊髓矢状径进行测量，比较椎间盘平面和椎体平面各测量值异同。设计、时间及地点：对比分析，于2006-03/2007-04在解放军第二军医大学长征医院完成。参试者：选取门诊招募的无颈脊髓的神经症状和体征志愿者120例，男48例，女72例；年龄17-71岁，平均41.4岁。方法：所有受试者行颈椎MRI检查，在MRI片上，对各节段（椎体平面和椎间盘平面）颈脊髓矢状径、颈椎管有效矢状径进行测量，并计算颈脊髓矢状径与颈椎管有效矢状径的比值。主要观察指标：椎体平面脊髓矢状径，椎间盘平面脊髓矢状径，椎体平面椎管有效矢状径，椎间盘节段椎管有效矢状径，同节段脊髓矢状径和有效椎管矢状径的比值。结果：椎体平面平均脊髓矢状径大于椎间盘平面平均脊髓矢状径（t=2.42，P〈0.01）；椎体平面平均椎管有效矢状径大于椎间盘平面平均椎管有效矢状径（t=2.67，P〈0.01）；椎体平面平均脊髓和椎管有效矢状径比值、椎间盘平面平均脊髓和椎管有效矢状径比值及全部节段的平均脊髓和有效椎管有效矢状径比值比较差异无显著性（F=0.703，P=0.495）。结论：椎间盘平面的脊髓矢状径和颈椎管有效矢状径与椎体节段是明显不同的，在测量中不能忽视椎间盘平面的测量；颈脊髓矢状径和椎管有效矢状径比值可作为评价颈脊髓病变的客观标准。

BACKGROUND： The measurement of sagittal diameter of the cervical spinal cord is simple, and the results can reflect spinal cord status in vertebral canal. Previous measurements are commonly involved in vertebral plane, but measurements at disc plane are rare. OBJECTIVE： To compare the difference of measurement of sagittal diameter of the cervical spinal cord at disc versus vertebral planes by MRI. DESIGN, TIME AND SETTING： Comparative analysis was performed at Changzheng Hospital Second Military Medical University of Chinese PLA from March 2006 to April 2007. PARTICIPANTS： 120 volunteers with no cervical spinal diseases were selected from Clinic Outpatient of Changzheng Hospital from March 2006 to April 2007, including 48 males and 72 females, with an average of 41.4 years （range, 17-71 years）. METHODS： The cervical MRI of all participants was performed. The sagittal diameters of cervical spinal cord and effective sagittal diameters of cervical spinal canal at each segment （disc and vertebral planes） were measured to calculate the ratio of sagittal diameters of cervical spinal cord and effective sagittal diameters of cervical spinal canal. MAIN OUTCOME MEASURES： Sagittal diameters of cervical spinal cord at disc and vertebral planes, effective sagittal diameters of cervical spinal canal, and ratio of sagittal diameters of cervical spinal cord and effective sagittal diameters of cervical spinal canal. RESULTS： Mean diameters of cervical spinal cord at vertebral plane were significantly larger than those at disc plane （t=2.42, P 〈 0.01 ）; effective sagittal diameters of cervical spinal canal at vertebral plane were significantly larger than those at disc plane （t =2.67, P 〈 0.01）. However, there were no significantly differences among the ratio of effective sagittal diameters of cervical spinal cord and cervical spinal canal at vertebral plane or at disc plane and the ratio of diameters in total segments （F =0.703, P =0.495）. CONCLUSION： The diameters of cervical spinal cord and cervical spinal canal at disc plane are significantly different from those at vertebral plane, so the measurement at disc plane is necessary. The ratio of diameters of cervical spinal cord and cervical spinal canal can function as an objective radiographic criterion to define and quantify cervical spinal cord disease.