Abstract: Objective  To assess the diffusion changes of normal appearing spinal cord (NASC) in MRI examination in patients with neuromyelitis optica (NMO) and multiple sclerosis (MS).  Methods  Axial diffusion tensor imaging (DTI) of cervical cord was performed in 10 patients with NMO, 14 patients with MS and 13 sex- and age-matched healthy controls. Mean diffusivity (MD) and fractional anisotropy (FA) were measured in the C_2-5 level of spinal cord. Regions of interest (ROIs) were placed in the anterior, lateral, posterior funiculi of spinal cord, and the central gray matter of spinal cord.  Results  Compared with healthy controls, the values of FA in anterior, lateral and posterior funiculi of spinal cord were significantly decreased (P < 0.05, for all) and MD in left lateral funiculus, posterior funiculus and gray matter were significantly increased (P ≤ 0.05, for all) in NMO group, and the FA values of right lateral and posterior funiculi in MS group were significantly decreased (P < 0.05, for all). Compared with MS group, FA value in patients with NMO was significantly decreased in lateral funiculus, and MD value in left lateral and right posterior funiculi were significantly increased (P < 0.05, for all).  Conclusions  NASC diffusion abnormalities were found both in patients with NMO and MS. The difference of DTI indicators between NMO and MS patients may offer important information in the early diagnosis and differential diagnosis of NMO and MS.

Key words: Neuromyelitis optica, Multiple sclerosis, Magnetic resonance imaging

摘要： 目的 通过扩散张量成像（DTI）比较视神经脊髓炎和多发性硬化患者与正常对照者常规MRI 表现正常脊髓的扩散性差异，并探讨其临床应用价值。方法 采用平面回波成像技术对10 例视神经脊髓炎、14 例多发性硬化患者和13 例正常对照者进行颈髓DTI 检查，分别测量颈椎C_{2 ~ 5} 水平前索、侧索、后索和灰质兴趣区的部分各向异性（FA）和平均扩散率（MD）。结果 与正常对照组相比，视神经脊髓炎组患者前索、侧索、后索FA 值降低（均P < 0.05），左侧侧索、后索、灰质MD 值升高（均P ≤ 0.05）；多发性硬化组患者右侧侧索、后索FA 值降低（均P < 0.05）。与多发性硬化患者相比，视神经脊髓炎患者侧索FA 值更低，左侧侧索和右侧后索MD 值更高（均P < 0.05）。结论 DTI 可以检出视神经脊髓炎和多发性硬化患者常规MRI表现正常脊髓的水分子扩散异常，进而发现二者脊髓扩散指标的差异性，为早期诊断与鉴别诊断提供重要信息。

关键词: 视神经脊髓炎, 多发性硬化, 磁共振成像