Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China.
Children's Hospital, National Clinical Research Center for Child Health, Zhejiang University School of Medicine, Hangzhou, China.
Magn Reson Med. 2025 Feb;93(2):803-813. doi: 10.1002/mrm.30310. Epub 2024 Oct 7.
To compare the myelin water fraction (MWF) measurements between 3 T and 7 T and between in vivo and ex vivo human brains, and to investigate the relationship between multi-echo gradient-echo (mGRE)-based 3D MWF and myelin content using histological staining, which has not been validated in the human brain.
In this study, we performed 3D mGRE-based MWF measurements on five ex vivo human brain hemispheres and five healthy volunteers at 3 T and 7 T with 1 mm isotropic resolution. The data were fitted with the based on a three compartment complex-valued model to estimate MWF. We obtained myelin basic protein (MBP) staining from two tissue blocks and co-registered the MWF map and histology image for voxel-wise correlation between the two.
The MWF values measured from 7 T were overall higher than 7 T, but data between the two field strength demonstrated high correlations both in vivo (r = 0.88) and ex vivo (r = 0.83) across 19 white matter regions. Moreover, the MWF measurements showed a good agreement between in vivo and ex vivo assessments at 3 T (r = 0.61) and 7 T (r = 0.54). Based on MBP staining, the MWF values exhibited strong positive correlations with myelin content on both 3 T (r = 0.68 and r = 0.78 for the two tissue blocks) and 7 T (r = 0.64 and r = 0.82 for the two tissue blocks).
The findings demonstrated that the mGRE-based MWF mapping can be used to quantify myelin content in the human brain, despite the field-strength dependency of the measurements.
比较 3T 和 7T 之间以及体内和离体人脑之间的髓鞘水分数（MWF）测量值，并利用组织学染色研究基于多回波梯度回波（mGRE）的 3D MWF 与髓鞘含量之间的关系，这在人脑内尚未得到验证。
本研究在 3T 和 7T 下对 5 个离体人脑半球和 5 名健康志愿者进行了基于 3D mGRE 的 MWF 测量，空间分辨率为 1mm 各向同性。使用基于三组分复值模型对数据进行拟合，以估计 MWF。我们从两个组织块中获得髓鞘碱性蛋白（MBP）染色，并对 MWF 图和组织学图像进行配准，以进行两个图之间的体素相关性分析。
7T 测量的 MWF 值总体上高于 3T，但在 19 个白质区域，两种场强下的数据在体内（r=0.88）和体外（r=0.83）均具有高度相关性。此外，3T（r=0.61）和 7T（r=0.54）的体内和体外评估之间的 MWF 测量值具有良好的一致性。基于 MBP 染色，MWF 值与两种组织块的髓鞘含量呈强正相关（r=0.68 和 r=0.78；r=0.64 和 r=0.82）。
这些发现表明，尽管测量存在场强依赖性，但基于 mGRE 的 MWF 映射可用于定量人脑的髓鞘含量。
