Oppong Philip Kyeremeh Jnr, Hamaguchi Hiroyuki, Kitagawa Maho, Patzke Nina, Wakeman Kevin C, Tha Khin Khin
Laboratory for Biomarker Imaging Science, Graduate School of Biomedical Science and Engineering, Hokkaido University, N15 W7, Kita-ku, Sapporo 060-8638, Japan.
Department of Radiological Technology, Hokkaido University Hospital, N14 W5, Kita-ku, Sapporo 060-8648, Japan.
Tomography. 2025 Jan 14;11(1):8. doi: 10.3390/tomography11010008.
Although multiple magnetic resonance imaging (MRI) indices are known to be sensitive to the noninvasive assessment of myelin integrity, their relative sensitivities have not been directly compared. This study aimed to identify the most sensitive MRI index for characterizing myelin composition in the spinal cord's gray matter (GM) and white matter (WM). MRI was performed on a deer's ex vivo cervical spinal cord. Quantitative indices known to be sensitive to myelin, including the myelin water fraction (MWF), magnetization transfer ratio (MTR), the signal ratio between T1- and T2-weighted images (T1W/T2W), fractional anisotropy (FA), mean diffusivity (MD), electrical conductivity (σ), and T1, T2, and T1ρ relaxation times were calculated. Their mean values were compared using repeated measures analysis of variance (ANOVA) and post hoc Bonferroni tests or Friedman and post hoc Wilcoxon tests to identify differences across GM and WM columns possessing distinct myelin distributions, as revealed by histological analysis. Relationships among the indices were examined using Spearman's rank-order correlation analysis. Corrected < 0.05 was considered statistically significant. All indices except σ differed significantly between GM and all WM columns. Two of the three WM columns had significantly different MWF, FA, MD, and T2, whereas one WM column had significantly different MTR, σ, T1, and T1ρ from the others. A significant moderate to very strong correlation was observed among most indices. The sensitivity of MRI indices in distinguishing spinal cord regions varied. A strategic combination of two or more indices may allow the accurate differentiation of spinal cord regions.
尽管已知多种磁共振成像（MRI）指标对髓鞘完整性的无创评估敏感，但其相对敏感性尚未得到直接比较。本研究旨在确定用于表征脊髓灰质（GM）和白质（WM）中髓鞘成分的最敏感MRI指标。对一只鹿的离体颈脊髓进行了MRI检查。计算了已知对髓鞘敏感的定量指标，包括髓鞘水分数（MWF）、磁化传递率（MTR）、T1加权和T2加权图像之间的信号比（T1W/T2W）、分数各向异性（FA）、平均扩散率（MD）、电导率（σ）以及T1、T2和T1ρ弛豫时间。使用重复测量方差分析（ANOVA）以及事后Bonferroni检验或Friedman检验和事后Wilcoxon检验比较它们的平均值，以确定在组织学分析显示具有不同髓鞘分布的GM和WM柱之间的差异。使用Spearman等级相关分析检查指标之间的关系。校正后P<0.05被认为具有统计学意义。除σ外，所有指标在GM和所有WM柱之间均存在显著差异。三个WM柱中的两个在MWF、FA、MD和T2方面存在显著差异，而一个WM柱在MTR、σ、T1和T1ρ方面与其他柱存在显著差异。大多数指标之间观察到显著的中度至非常强的相关性。MRI指标区分脊髓区域的敏感性各不相同。两个或更多指标的策略性组合可能有助于准确区分脊髓区域。
