平山病屈曲位MRI的影像学特征

Flexion MRI Features of Hirayama Disease

目的探讨平山病的屈曲位MR影像学特征及其病理学机制。方法回顾性分析临床确诊为平山病的31例患者的颈椎屈曲位MRI表现，其中10例同期行过伸和屈曲位MR检查。结果31例患者均出现低位颈髓的萎缩变扁；其中非对称性变扁28例，对称性变扁3例；下段颈髓T2WI异常高信号患者4例；所有病例出现硬脊膜外后间隙增宽，其中29例T2WI砸示增宽的硬膜外后间隙内出现小流空信号，10例同期行过伸、属曲位MRI检查者皆显示硬脊膜囊后肇前移。3例接受颈椎减压手术治疗的患者，术后显示：术前增宽的硬膜外后脂肪间隙恢复正常，其内的流空信号也消失。结论平山病的颈椎屈曲位MRI表现具有特征性，颈椎屈曲位MRI对平山病的早期诊断及其发病机制的探讨和治疗后随访具有重要价值。

Objective To explore the flexion MRI features and the possible pathogenesis of Hirayama disease. Method 31 cases with Hirayama disease received flexion MRI examination,while 10 cases of them got extension MRI examination.Results On flexion MRI,all cases demonstrated the lower cervical cord atrophy,28 of them with asymmetric cord flattening,3 with symmetric cord flattening, and 4 with hyperintensity on T2WI.All cases showed the passive dilation of the posterior epidural space,29 with smaill flow void signals inside it on T2WI. 10 cases receiving both flexion and extension MRI examinations showed the forward displacement of the dural sac.After the operation of cervical decompression on 3 cases, the shifting dura mater had returned to its normal position, meanwhile, the flow void signals inside it disappeared.Conclusion The appearance of flexion MRI of Hirayama disease is characteristic and flexion MRI is a very valuable method to early diagnosis and follow-up and exploration ofpathogenesis of Hirayama disease.