Reproducibility, temporal stability, and functional correlation of diffusion MR measurements within the spinal cord in patients with asymptomatic cervical stenosis or cervical myelopathy
Reproducibility, temporal stability, and functional correlation of diffusion MR measurements within the spinal cord in patients with asymptomatic cervical stenosis or cervical myelopathy
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DOI：
10.3171/2017.7.spine176
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发表时间：
2018-05-01
影响因子：
2.8
通讯作者：
Holly, Langston T.
中科院分区：
文献类型：
--
作者：
Ellingson, Benjamin M.;Salamon, Noriko;Holly, Langston T.
目的 本研究的目的是量化伴或不伴脊髓病的颈椎狭窄患者脊髓弥散 MR 特征的再现性、时间稳定性和功能相关性。在群体和个人水平上探讨了纵向扩散张量成像 (DTI) 测量与连续神经功能评估之间的关联。 方法 使用同步连续 MRI 和功能结果评估对 66 名非手术治疗的颈椎狭窄患者进行前瞻性随访（3 个月至 > 5 年）。总共进行了 183 次单独的 MRI 检查，间隔至少 3 个月，每个患者至少进行 2 次 MRI 扫描（范围 2-5 次扫描）。在脊髓内的 C1-2 区域以及最高压缩区域进行了解剖学和 DTI 测量。比较了参考组织和压缩区域的方差系数 (COV)，以进行解剖测量、部分各向异性 (FA) 和平均扩散率 (MD)。评估了受压部位的弥散 MR 测量值与使用改良的日本骨科协会 (mJOA) 量表在多个时间点评估的神经功能评估之间的相关性。 结果 解剖测量值（Torg 比和根管直径）的 COV 在 7% 至 10% 之间。压缩部位 FA 测量的 COV 中位数为 9%，C1-2 参考组织的 COV 中位数为 6%。 MD 受压部位的 COV 中值约为 12%，而 C1-2 处的参考组织为 10%。 C1-2 的 FA 和 MD 测量值平均分别为 0.61 和 0.91 μ m(2)/msec，而压缩部位的 FA 和 MD 测量值平均分别为 0.51 和 1.26 μ m(2)/msec。 FA（斜率 = 0.037，R-2 = 0.3281，p < 0.0001）和 MD（斜率 = -0.074，R-2 = 0.1101，p = 0.0084）均与 mJOA 评分显着相关。每减少一个 mJOA 单位，FA 就会减少约 0.032 个单位（R-2 = 0.2037，p < 0.0001），而每减少一个 mJOA 单位，MD 就会增加约 0.084 μ m(2)/毫秒（R-2 = 0.1016，p < 0.0001）。 结论 颈椎病患者脊髓的定量 DTI 测量伴有或不伴有脊髓病的狭窄的中位 COV 为 5%-10%，与解剖测量结果类似。这些测量的可重复性以及与功能结果状态的显着相关性表明在非手术治疗患者的评估和纵向监测中具有潜在作用。就特定的 DTI 测量而言，脊髓内的 FA 似乎对神经功能稍敏感，并且比 MD 的测量更稳定。因此，脊髓 DTI 可能是一种临床上可行的影像学技术，用于纵向监测脊髓型颈椎病患者。
OBJECTIVE The purpose of this study was to quantify the reproducibility, temporal stability, and functional correlation of diffusion MR characteristics in the spinal cord in patients with cervical stenosis with or without myelopathy. The association between longitudinal diffusion tensor imaging (DTI) measurements and serial neurological function assessment was explored at both the group and individual level.METHODS Sixty-six nonoperatively treated patients with cervical stenosis were prospectively followed (3 months to > 5 years) using synchronous serial MRI and functional outcome assessment. A total of 183 separate MRI examinations were performed, separated by at least 3 months, and each patient had a minimum of 2 MRI scans (range 2-5 scans). Anatomical and DTI measurements were performed within the spinal cord at the C1-2 region as well as at the area of highest compression. Coefficients of variance (COVs) were compared across measurements in both reference tissue and areas of compression for anatomical measurements, fractional amsotropy (FA), and mean diffusivity (MD). The correlation between diffusion MR measures at the site of compression and evaluations of neurological function assessed using the modified Japanese Orthopaedic Association (mJOA) scale at multiple time points was evaluated.RESULTS The COVs for anatomical measurements (Torg ratio and canal diameter) were between 7% and 10%. The median COV for FA measurements at the site of compression was 9%, and for reference tissue at C1-2 it was 6%. The median COV for MD at the site of compression was approximately 12%, and for reference tissue at C1-2 it was 10%. The FA and MD measurements of C1-2 averaged 0.61 and 0.91 mu m(2)/msec, respectively, whereas the FA and MD measurements at the site of compression averaged 0.51 and 1.26 mu m(2)/msec, respectively. Both FA (slope = 0.037, R-2 = 0.3281, p < 0.0001) and MD (slope = -0.074, R-2 = 0.1101, p = 0.0084) were significantly correlated with the mJOA score. The FA decreased by approximately 0.032 units per mJOA unit decrease (R-2 = 0.2037, p < 0.0001), whereas the MD was increased by approximately 0.084 mu m(2)/msec for every mJOA unit decrease (R-2 = 0.1016, p < 0.0001).CONCLUSIONS Quantitative DTI measurements of the spinal cord in patients with cervical stenosis with or without myelopathy have a median COV of 5%-10%, similar to anatomical measurements. The reproducibility of these measurements and significant correlation with functional outcome status suggest a potential role in the evaluation and longitudinal surveillance of nonoperatively treated patients. With respect to the specific DTI measurements, FA within the spinal cord appears slightly more sensitive to neurological function and more stable than measures of MD. Therefore, DTI of the spinal cord may be a clinically feasible imaging technique for longitudinally monitoring patients with cervical spondy-lotic myelopathy.