On the role of neuronal magnetic susceptibility and structure symmetry on gradient echo MR signal formation.
On the role of neuronal magnetic susceptibility and structure symmetry on gradient echo MR signal formation.
复制标题
DOI：
10.1002/mrm.24629
复制
发表时间：
2014-01
影响因子：
3.3
通讯作者：
Yablonskiy, Dmitriy A.
中科院分区：
文献类型：
--
作者：
Sukstanskii, Alexander L.;Yablonskiy, Dmitriy A.
通过梯度回波（GRE）MRI获得的相位图像提供了新的对比度，与传统的T1加权和T2加权图像不同。结果是特别有趣的白色的问题，信号的幅度和相位显示各向异性。然而，这些现象的生物物理起源还没有得到很好的理解。本文的目标是提供一个全面的GRE信号形成理论的基础上，一个现实的神经元结构模型。我们利用麦克斯韦方程组来求解髓鞘和轴突所产生的磁场分布。我们解释了神经元组织“磁微结构”的各向异性和髓鞘磁化率的各向异性。模型描述了GRE信号包括三个隔室-轴突，髓鞘和细胞外。轴突和髓鞘水信号都具有受形成脂质双层膜的长分子的磁化率各向异性影响的频率偏移。这些部分的频移达到极端的轴突定向垂直于磁场和零的平行的情况下。髓鞘水信号基本上是非单指数的。神经元组织磁微结构的各向异性和髓鞘磁化率的各向异性对于描述GRE信号的相位和幅度都很重要。
Phase images obtained by gradient-recalled echo (GRE) MRI provide new contrast in the brain that is distinct from that obtained with conventional T1-weighted and T2-weighted images. The results are especially intriguing in white matter where both signal amplitude and phase display anisotropic properties. However, the biophysical origins of these phenomena are not well understood. The goal of this paper is to provide a comprehensive theory of GRE signal formation based on a realistic model of neuronal structure. We use Maxwell equations to find the distribution of magnetic field induced by myelin sheath and axon. We account for both anisotropy of neuronal tissue “magnetic micro-architecture” and anisotropy of myelin sheath magnetic susceptibility. Model describes GRE signal comprising of three compartments – axonal, myelin and extracellular. Both axonal and myelin water signals have frequency shifts that are affected by the magnetic susceptibility anisotropy of long molecules forming lipid bi-layer membranes. These parts of frequency shifts reach extrema for axon oriented perpendicular to the magnetic field and are zeros in a parallel case. Myelin water signal is substantially non-monoexponential. Both, anisotropy of neuronal tissue “magnetic micro-architecture” and anisotropy of myelin sheath magnetic susceptibility, are important for describing GRE signal phase and magnitude.
登录
查看更多内容
影响因子：
2.5
作者：
Liu, Tian;Spincemaille, Pascal;de Rochefort, Ludovic;Wong, Richard;Prince, Martin;Wang, Yi
通讯作者：
Wang, Yi
影响因子：
3.3
作者：
CHU, SCK;XU, Y;SPRINGER, CS
通讯作者：
SPRINGER, CS
DOI：
10.1073/pnas.0910222107
发表时间：
2010-03-16
影响因子：
11.1
作者：
Lee, Jongho;Shmueli, Karin;Duyn, Jeff H.
通讯作者：
Duyn, Jeff H.
影响因子：
3.3
作者：
He, Xiang;Yablonskiy, Dmitriy A.
通讯作者：
Yablonskiy, Dmitriy A.
影响因子：
5.7
作者：
Lee, Jongho;Hirano, Yoshiyuki;Fukunaga, Masaki;Silva, Afonso C.;Duyn, Jeff H.
通讯作者：
Duyn, Jeff H.