Simulations on the influence of myelin water in diffusion-weighted imaging.
Simulations on the influence of myelin water in diffusion-weighted imaging.
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DOI：
10.1088/0031-9155/61/13/4729
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发表时间：
2016-07-07
影响因子：
3.5
通讯作者：
Does MD
中科院分区：
文献类型：
--
作者：
Harkins KD;Does MD
虽然髓鞘轴突是水扩散的重要屏障，但许多用于解释DWI信号的模型忽略了髓鞘的其他潜在影响。在这项工作中，蒙特卡罗模拟用于测试DWI结果对髓鞘内水扩散特性的敏感性。在这些模拟中，表观扩散系数（Dapp）在髓磷脂水扩散系数（Dm）的几个数量级上缓慢变化，但与忽略Dm（=0）的模拟Dapp值相比表现出重要差异。与Dapp相比，表观扩散峰度（Kapp）通常对Dm更敏感。模拟还测试了Dapp和Kapp对髓磷脂存在量的敏感性。髓磷脂体积分数差异引起的Dapp和Kapp的独特变化在髓磷脂水扩散时减弱。此外，在考虑髓鞘水扩散时，Dapp和Kapp随实验回波时间的预期趋势降低或反转，并且在离体大鼠脑DWI实验中可以看到这些降低/反转趋势。一般来说，髓鞘水有可能微妙地影响DWI结果和忽略这些白质成分的DWI偏差模型。
While myelinated axons present an important barrier to water diffusion, many models used to interpret DWI signal neglect other potential influences of myelin. In this work, Monte Carlo simulations were used to test the sensitivity of DWI results to the diffusive properties of water within myelin. Within these simulations, the apparent diffusion coefficient (Dapp) varied slowly over several orders of magnitude of the coefficient of myelin water diffusion (Dm), but exhibited important differences compared to Dapp values simulated that neglect Dm (=0). Compared to Dapp, the apparent diffusion kurtosis (Kapp) was generally more sensitive to Dm. Simulations also tested the sensitivity of Dapp and Kapp to the amount of myelin present. Unique variations in Dapp and Kapp caused by differences in the myelin volume fraction were diminished when myelin water diffusion was included. Also, expected trends in Dapp and Kapp with experimental echo time were reduced or inverted when accounting for myelin water diffusion, and these reduced/inverted trends were seen experimentally in ex vivo rat brain DWI experiments. In general, myelin water has the potential to subtly influence DWI results and bias models of DWI that neglect these components of white matter.