Department Neurosciences, Imaging, and Clinical Sciences, Institute for Advanced Biomedical Technologies, ITAB, Gabriele D'Annunzio University, Chieti, Italy.
MAGMA. 2021 Aug;34(4):523-543. doi: 10.1007/s10334-020-00899-5. Epub 2021 Jan 8.
To evaluate: (a) the specific effect that the demyelination and axonal loss have on the DW signal, and (b) the impact of the sequence parameters on the sensitivity to damage of two clinically feasible DWI techniques, i.e. DKI and NODDI.
We performed a Monte Carlo simulation of water diffusion inside a novel synthetic model of white matter in the presence of axonal loss and demyelination, with three compartments with permeable boundaries between them. We compared DKI and NODDI in their ability to detect and assess the damage, using several acquisition protocols. We used the F test statistic as an index of the sensitivity for each DWI parameter to axonal loss and demyelination, respectively.
DKI parameters significantly changed with increasing axonal loss, but, in most cases, not with demyelination; all the NODDI parameters showed sensitivity to both the damage processes (at p < 0.01). However, the acquisition protocol strongly affected the sensitivity to damage of both the DKI and NODDI parameters and, especially for NODDI, the parameter absolute values also.
This work is expected to impact future choices for investigating white matter microstructure in focusing on specific stages of the disease, and for selecting the appropriate experimental framework to obtain optimal data quality given the purpose of the experiment.
评估（a）脱髓鞘和轴突损失对 DW 信号的具体影响，以及（b）序列参数对两种临床可行的 DWI 技术（即 DKI 和 NODDI）损伤敏感性的影响。
我们在存在轴突损失和脱髓鞘的新型白质合成模型内进行了水扩散的蒙特卡罗模拟，该模型具有三个具有可渗透边界的隔室。我们比较了 DKI 和 NODDI 在使用几种采集方案检测和评估损伤方面的能力。我们使用 F 检验统计量作为每个 DWI 参数对轴突损失和脱髓鞘分别敏感的指标。
DKI 参数随着轴突损失的增加而显著变化，但在大多数情况下，与脱髓鞘无关；所有 NODDI 参数均对两种损伤过程敏感（p<0.01）。然而，采集方案强烈影响了 DKI 和 NODDI 参数的损伤敏感性，特别是对于 NODDI，参数的绝对值也会受到影响。
这项工作有望影响未来在关注疾病特定阶段和选择适当的实验框架以在给定实验目的的情况下获得最佳数据质量方面对研究白质微观结构的选择。
