Using the biophysical CHARMED model to elucidate the underpinnings of contrast in diffusional kurtosis analysis of diffusion-weighted MRI
Using the biophysical CHARMED model to elucidate the underpinnings of contrast in diffusional kurtosis analysis of diffusion-weighted MRI
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DOI：
10.1007/s10334-011-0292-5
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发表时间：
2012-08-01
影响因子：
2.3
通讯作者：
Jones, Derek K.
中科院分区：
文献类型：
--
作者：
De Santis, Silvia;Assaf, Yaniv;Jones, Derek K.
这项工作的目的是使用复合受阻和受限扩散模型 (CHARMED) 了解白质扩散峰度成像 (DKI) 中支撑对比度的生物物理底物。峰度函数 K 与 CHARMED 参数（即受限体积分数 RF 和轴突纵向扩散率 D）之间的理论关系是为 CHARMED 模型中使用的传播器推导的。然后，对在 3T 下接受 CHARMED 方案的 5 名健康年轻受试者的不同 WM 区域的体内研究了这些测量值之间类似相关性的证据。我们的理论治疗表明，K 随 RF 值的增加和 D 的增加而呈增加趋势。在体内，发现与纤维取向 K (aSyen) 正交的峰度和 RF 之间存在显着的正相关性 (P < 0.001)。多线性回归表明，K (aSyen) 值可以通过 RF 和 D 的混合贡献得到更好的解释。CHARMED 模型用于了解是否以及在何处可以根据底层轴突几何形状来解释 DKI 对比度。这项工作表明，DKI 中包含的信息与 CHARMED 在较高体素内方向相干性的区域中提取的信息重叠。
The aim of this work was to understand biophysical substrate underpinning contrast in diffusional kurtosis imaging (DKI) in white matter, using the composite hindered and restricted model of diffusion (CHARMED).A theoretical relationship between the kurtosis function K and the CHARMED parameters, i.e., the restricted volume fraction RF and the axonal longitudinal diffusivity D was derived for the propagator used in the CHARMED model. Evidence for a similar correlation between these measures was then investigated in vivo across different WM regions in five healthy young subjects that underwent a CHARMED protocol at 3T.Our theoretical treatment shows that K has an increasing trend for both increasing RF values and increasing D. In vivo, a significant positive correlation (P < 0.001) was found between the kurtosis orthogonal to the fibre orientation K (aSyen) and RF. A multilinear regression showed that K (aSyen) values are better explained by a mixed contribution of both RF and D.The CHARMED model was used to understand whether and where DKI contrast can be explained in terms of the underlying axonal geometry. This work demonstrates that the information contained in DKI overlaps with the information extracted by CHARMED in areas of higher intra-voxel directional coherence.