自然位磁共振影像对平山病的诊断价值

Neutral position magnetic resonance imaging for diagnosis of hirayama disease

目的探讨低位颈髓自然位各种影像学改变对平山病的诊断价值。方法观察18例患者和31例对照自然位颈MRI各种影像改变的敏感性、特异性和相关性。结果(1)病例和对照间,低位颈髓萎缩,变扁平,失连接有统计学差异(P<0．05)。(2)失连接与平山病有显著相关OR= 49．38(95％CI:3．97～614．73,P=0．002),灵敏性和特异性分别为88．0％,90．6％。(3)低位颈髓萎缩的灵敏性84．6％,特异性80．6％。变扁平的灵敏性87．5％,特异性73．2％,与平山病均无显著相关性。结论平山病低位颈髓在自然位MRI的失连接可协助诊断。

Objective To investigate the sensitivity and specificity of neutral position cervical MRI in the diagnosis of Hirayama disease. Methods Neutral position cervical MRI of 18 patients and 31 young normal control subjects were evaluated for localized lower cervical cord atrophy, asymmetric cord flattening, abnormal cervical curvature, loss of attachment （LOA） and noncompressed intramedullary high signal intensity on T2-weighted MRI. The difference in frequency of these findings between the control and patient groups was examined by means of the x＇test. The sensitivity and specificity of these MRI findings in the diagnosis of Hirayama disease were calculated. Multiple logistic regression was performed to explore the relationship with Hirayama disease. Results （1） There was significant difference in the frequency of localized lower cervical cord atrophy, asymmetric cord flattening and LOA between the patient and control groups （P 〈 0.05 ）. （2） After adjusting localized lower cervical cord atrophy, asymmetric cord flattening, abnormal cervical curvature and LOA, the analysis showed that LOA was the only significantly important predictor of the disease, with odds ratio of 49. 38 （95% CI： 3.97-614. 73 ）. Sensitivity and specificity of LOA were 88.0% and 90. 6% respectively. （ 3 ） Sensitivity and specificity of localized lower cervical cord atrophy were 84. 6% and 80. 6%. Sensitivity and specificity of asymmetric cord flattening were 87. 5% and 73.2% , but our case-control study did not fine any significant association between localized lower cervical cord atrophy and Hirayama disease and also between asymmetric cord flattening and Hirayama disease. Conclusions LOA between posterior dural sac and subjacent lamina is the most valuable finding in the diagnosis of Hirayama disease at neutral position MR imaging.