平山病中心位及过屈位颈髓磁共振成像特点

Features of Cervical Cord MRI with Neutral and Flexion Positions of Hirayama Disease

目的观察平山病颈部正常位及过屈位磁共振成像(MRI)特点,对平山病发病机制进行初步探讨。方法20例确诊平山病患者进行正常位及过屈位颈段脊髓MRI检查。结果20例患者经中立位颈髓MRI检查结果显示,其中10例下颈段脊髓存在萎缩变平现象且与萎缩侧肢体一致,萎缩节段以第6颈椎水平最明显。过屈位颈段MRI检查发现14例(70%)存在硬膜囊后壁前移现象,硬膜外腔内可见月牙形长T1长T2信号影,向前压迫脊髓;14例(70%)硬膜外腔内有异常扩张的血管流空信号,3例(15%)髓内有长T1长T2信号。结论颈部前屈动力学改变以及血管因素可能在平山病发病机制中起一定作用。

Objective To make a comprehensive understanding of cervical MRI with the neck in neutral and flexion positions and investigate the mechanism of Hirayama disease. Methods A detailed neurological examination, cervical MRI in neck flexion and neutral positions were performed in 20 patients. Results Nonflexion cervical sagittal MR images revealed cord atrophy at the C5-T1 vertebral levels, especially at C6 in 10 patients. Sagittal and axial T1-and T2-weighted images showed anterior displacement of the posterior wall of the cervical dural canal in 14（70%） patients. An epidural mass, isointense with the cord on T1-weighted images and T2-weighted images, was noted at the posterior aspect of the lower cervical dural canal in 14 patients with some small flow void signals inside it. Intramedullary signal abnormalities were detected in 3 patients. Conclusions Hirayama disease was a nonprogressive juvenile spinal muscular atrophy of the distal upper limbs. Special MRI findings in neck flexion were remarkable. The dynamic changes and abnormal vascularity in neck flexion might make involvements in the pathogenesis of Hirayama disease.