正常上颈髓面积的活体MRI测量与标准化

Measurement and Normalization of Normal Upper Cervical Cord Area in Vivo by MRI

目的:上颈髓面积(UCCA)是普遍接受并且易于测量的评估脊髓萎缩的参数。应用3D-MRI技术结合半自动测量技术测量健康中国人的上颈髓面积(UCCA),探讨最大腰髓面积(MLCA)是否是理想的UCCA校正参数。方法:应用3D-MRI技术分别获取51例健康人的颈髓和腰髓的头颅矢状面及横断面图像,应用半自动测量技术分别测量上颈髓面积、颅腔矢状面最大面积(ICA)、颅腔横断面最大面积(MICA)和腰髓最大横断面面积(MLCA),对它们的测量可重复性分别进行评估,分析UCCA与这几种潜在校正参数的相关性并用这几种校正参数分别对上颈髓面积进行校正。结果:健康成年人UCCA为(80.00±7.22)mm2,变异系数为9.0%。其中UCCA与MLCA的测量可重复性比其它两项参数高,UCCA与MLCA有显著相关性(r=0.88,P<0.01)。采用MLCA校正后,UCCA的变异系数由9.3%下降到4.4%。结论:利用MRI结合半自动测量技术能准确活体测量上颈髓面积,MLCA是理想的校正参数。

Objective：The upper cervical cord area （UCCA） is an acknowledged and easily gauged measurement to assess spinal cord atrophy. This study is to use 3D-MRI in combination with semi-automatic measuring technique to measure the UCCA of healthy Chinese adults and to investigate whether maximum lumbar cord area （MLCA） is a valid and optimized correction factor for upper cervical cord area （UCCA）. Methods： The sagittal and axial plane images of the cervical cord,lumbar cord and cranium of 51 healthy Chinese were obtained by 3D-MRI technique, UCCA, mid-sagittal intracranial area （ICA）,maximum intracranial cross section area （MICA） and MLCA were measured and their reliability of repetition were evaluated respectively. The linear relationships between UCCA and these potential correction factors were analyzed. Then,UCCA was normalized by these factors respectively. Results： Of these healthy Chinese adults, normal value of UCCA was （80±7.22）mm^2 and the coefficient of variation （COV） was 9.0%. The reliability of repetition of UCCA and MLCA were higher than the others with significant correlation （r=0. 88,P〈0. 01）. The COV of UCCA was reduced to 4.4% from 9.3 % after corrected by MLCA. Conclusion： UCCA could be measured accurately in vivo by 3D-MRI technique in combination with semi-automatic measuring technique. MLCA is an optimal correction factor for UCCA.