Institute of Imaging Science (B.B.R., S.B., Q.R.W., A.A.W., A.T.N., H.R.F., B.R., S.A.S., A.B.), Vanderbilt University, Nashville, Tennessee.
From the Department of Radiology and Radiological Sciences (A.T.N., P.C., S.A.S., A.B.).
AJNR Am J Neuroradiol. 2019 Jul;40(7):1236-1241. doi: 10.3174/ajnr.A6104. Epub 2019 Jun 13.
The purpose of the study is to characterize diffusion tensor imaging indices in the developing spinal cord, evaluating differences based on age and cord region. Describing the progression of DTI indices in the pediatric cord increases our understanding of spinal cord development.
A retrospective analysis was performed on DTI acquired in 121 pediatric patients (mean, 8.6 years; range, 0.3-18.0 years) at Monroe Carell Jr. Children's Hospital at Vanderbilt from 2017 to 2018. Diffusion-weighted images (15 directions; = 750 s/mm; slice thickness, 5 mm; in-plane resolution, 1.0 × 1.0 mm) were acquired on a 3T scanner in the cervicothoracic and/or thoracolumbar cord. Manual whole-cord segmentation was performed. Images were masked and further segmented into cervical, upper thoracic, thoracolumbar, and conus regions. Analyses of covariance were performed for each DTI-derived index to investigate how age affects diffusion across cord regions, and 95% confidence intervals were calculated across age for each derived index and region. Post hoc testing was performed to analyze regional differences.
Analyses of covariance revealed significant correlations of age with axial diffusivity, mean diffusivity, and fractional anisotropy (all, < .001). There were also significant differences among cord regions for axial diffusivity, radial diffusivity, mean diffusivity, and fractional anisotropy (all, < .001).
This research demonstrates that diffusion evolves in the pediatric spinal cord during development, dependent on both cord region and the diffusion index of interest. Future research could investigate how diffusion may be affected by common pediatric spinal pathologies.
本研究旨在对发育中的脊髓的扩散张量成像（DTI）指数进行特征描述，评估基于年龄和脊髓区域的差异。描述小儿脊髓 DTI 指数的进展情况可增加我们对脊髓发育的理解。
对 2017 年至 2018 年期间在范德比尔特大学门罗·加勒尔儿童医院（Monroe Carell Jr. Children's Hospital at Vanderbilt）使用 3T 扫描仪获取的 121 例儿科患者（平均年龄 8.6 岁；范围 0.3-18.0 岁）的 DTI 进行了回顾性分析。在颈椎和/或胸腰椎脊髓上采集扩散加权图像（15 个方向；b 值=750 s/mm²；层厚 5mm；平面分辨率 1.0×1.0mm）。手动进行全脊髓分割。对图像进行掩蔽，并进一步分割为颈段、上胸段、胸腰段和圆锥段。对每个 DTI 衍生指数进行协方差分析，以研究年龄如何影响脊髓区域的扩散，计算每个衍生指数和区域的年龄 95%置信区间。进行事后检验以分析区域差异。
协方差分析显示，年龄与轴索弥散度、平均弥散度和各向异性分数（均，P<.001）显著相关。脊髓区域之间的轴索弥散度、径向弥散度、平均弥散度和各向异性分数也存在显著差异（均，P<.001）。
本研究表明，在儿童脊髓发育过程中，扩散会发生变化，这取决于脊髓区域和感兴趣的扩散指数。未来的研究可以调查扩散如何受常见的小儿脊髓病理影响。
