Objective

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.

Methods

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.

Results

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.

Discussion

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.

中文翻译：

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采集协议对临床可行的 DWI 技术对脱髓鞘和轴突丢失的敏感性的影响：模拟研究

客观的

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上可行的 DWI 技术（即 DKI 和 NODDI）的损伤敏感性的影响。

方法

我们在存在轴突损失和脱髓鞘的情况下，在新的白质合成模型中对水扩散进行了蒙特卡罗模拟，三个隔室之间具有可渗透的边界。我们使用多种采集协议比较了 DKI 和 NODDI 检测和评估损坏的能力。我们分别使用F检验统计量作为每个 DWI 参数对轴突损失和脱髓鞘的敏感性的指标。

结果

DKI 参数随着轴突损失的增加而发生显着变化，但在大多数情况下，与脱髓鞘无关；所有 NODDI 参数都显示出对两种损伤过程的敏感性（p  < 0.01）。然而，采集协议强烈影响了 DKI 和 NODDI 参数对损坏的敏感性，尤其是对于 NODDI，参数绝对值也是如此。

讨论

预计这项工作将影响未来的选择，以研究白质微观结构，重点关注疾病的特定阶段，并根据实验目的选择适当的实验框架以获得最佳数据质量。