Department of Neuro-Urology, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland.
NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, University College London, London, UK.
Sci Rep. 2022 Oct 3;12(1):16498. doi: 10.1038/s41598-022-20395-1.
Atrophy in the spinal cord (SC), gray (GM) and white matter (WM) is typically measured in-vivo by image segmentation on multi-echo gradient-echo magnetic resonance images. The aim of this study was to establish an acquisition and analysis protocol for optimal SC and GM segmentation in the lumbosacral cord at 3 T. Ten healthy volunteers underwent imaging of the lumbosacral cord using a 3D spoiled multi-echo gradient-echo sequence (Siemens FLASH, with 5 echoes and 8 repetitions) on a Siemens Prisma 3 T scanner. Optimal numbers of successive echoes and signal averages were investigated comparing signal-to-noise (SNR) and contrast-to-noise ratio (CNR) values as well as qualitative ratings for segmentability by experts. The combination of 5 successive echoes yielded the highest CNR between WM and cerebrospinal fluid and the highest rating for SC segmentability. The combination of 3 and 4 successive echoes yielded the highest CNR between GM and WM and the highest rating for GM segmentability in the lumbosacral enlargement and conus medullaris, respectively. For segmenting the SC and GM in the same image, we suggest combining 3 successive echoes. For SC or GM segmentation only, we recommend combining 5 or 3 successive echoes, respectively. Six signal averages yielded good contrast for reliable SC and GM segmentation in all subjects. Clinical applications could benefit from these recommendations as they allow for accurate SC and GM segmentation in the lumbosacral cord.
脊髓（SC）、灰质（GM）和白质（WM）萎缩通常通过多回波梯度回波磁共振图像的图像分割在体内进行测量。本研究的目的是在 3T 下建立一种用于腰骶脊髓 SC 和 GM 最佳分割的采集和分析方案。十名健康志愿者在西门子 Prisma 3T 扫描仪上使用西门子FLASH 的 3D 扰相多回波梯度回波序列（具有 5 个回波和 8 个重复）对腰骶脊髓进行成像。通过专家的可分割性进行定性评分，比较信噪比（SNR）和对比噪声比（CNR）值，研究了连续回波和信号平均的最佳数量。连续 5 个回波的组合产生了 WM 和脑脊液之间最高的 CNR 值和 SC 可分割性的最高评分。连续 3 个和 4 个回波的组合分别在腰骶部扩张和脊髓圆锥中产生了 GM 和 WM 之间最高的 CNR 值和 GM 可分割性的最高评分。对于在同一图像中分割 SC 和 GM，我们建议组合使用 3 个连续回波。对于仅分割 SC 或 GM，我们建议分别组合使用 5 个或 3 个连续回波。在所有受试者中，6 个信号平均可产生良好的对比度，以可靠地分割 SC 和 GM。这些建议可使临床应用受益，因为它们允许在腰骶脊髓中进行准确的 SC 和 GM 分割。
