平山病的MRI诊断价值

目的:探讨平山病的MR表现和价值,认识平山病的临床特征和可能的发病机制.方法:5例经临床确诊的平山病患者均隐匿起病,病变局限于上肢远端肌肉,4例单侧上肢前臂受累,1例双侧不对称性受累.5例患者均行颈椎X线平片检查,及颈髓常规自然体位MR平扫及屈颈位平扫 增强扫描.所有患者均进行常规生化检查,脑脊液检查,肌电图检查和肌肉活检.结果:5例患者普通X线检查4例可见颈椎生理曲度变直,自然体位MR平扫3例有低位脊髓萎缩变扁(萎缩水平在颈5-胸1,最明显在颈6水平),2例萎缩的脊髓内信号异常.曲颈MR检查时,除了可见自然体位MR的表现外,5例患者均可见特征性的颈髓前移、变平,硬脊膜向前移位,硬脊膜外腔增宽,4例患者在增宽的硬膜外腔均可见流空血管信号,增强扫描5例患者在增宽的硬脊膜外腔均可见强化的静脉丛.结论:平山病的MR表现存在一定的特征性,MR屈曲位平扫 增强扫描对平山病的诊断及其发病机制的理解有重要的价值.

MR Diagnostic Value of the Hirayama Disease

Objective:To explore the MR appearance and its diagnostic value,and to improve the knowledge of the clinical characteristics and the possible pathogenesis of the hirayama disease.Methods:5 cases with hirayama disease were screened and confirmed by clinic,all the patients showed insidious onset of muscle atrophy and weakness confined to the distal part of upper limbs,sparing the brachioradiulis muscles (oblique atrophy),four showed unilateral involvement and one showed bilateral but asymmetric involvement.All of them had the cervical lateral X-ray,neutral position and neck flexion position MR examination (pre-post contrast scans),the routine biochemical examination,cerebrospinal fluid examination,electromyogram and muscle biopsy were performed for all the cases.Results:The results of the general X-ray showed the abnormal cervical curvature in 4 patients.In the neck neutral position,4 patients showed the localized lower cervical cord atrophy,asymmetric cord flattening (cord atrophy at C5 to T1 level,particularly marked at C6),and 2 patients showed the signal abnormamities of the spinal cord.Except for the findings of the neutral position images,the neck flexion position MR images can also demonstrate the forward displacement of the dural sac together with passive dilation of the posterior epidural with some abnormal signal in all the patients,with small flow void signals insides the passive dilation of the posterior epidural space in 4 patients.On the post contrast flexion position MR images disclosed the venous plexus located in the passive dilation of the posterior epidural space.Conclusion:The Hirayama disease shows characteristic manifestations on MRI.Neck neutral position and flexion position MR pre and pro-contrast MR scans play an important role in the diagnosis of the hirayama disease and it benefits the understanding of pathogenesis mechanism for the disease.