Magnetic susceptibility induced white matter MR signal frequency shifts--experimental comparison between Lorentzian sphere and generalized Lorentzian approaches.
Magnetic susceptibility induced white matter MR signal frequency shifts--experimental comparison between Lorentzian sphere and generalized Lorentzian approaches.
复制标题
磁敏感性引起的白质MR信号频率转移 - 洛伦兹球体和广义洛伦兹方法之间的实验比较。
DOI：
10.1002/mrm.24762
复制
发表时间：
2014-03
影响因子：
3.3
通讯作者：
Yablonskiy, D. A.
中科院分区：
文献类型：
--
作者：
Luo, J.;He, X.;Yablonskiy, D. A.
关键词：
人脑高场梯度回波MRI研究中显著相衬的性质是一个激烈争论的主题。广义洛伦兹方法（GLA） （He & Yablonskiy, PNAS 2009;106:13558）为相衬各向异性、WM和CSF之间几乎没有相衬以及多发性硬化症相衬变化提供了解释。在本研究中，我们通过实验验证了GLA。GLA表明，WM中局部频移的贡献并不取决于平均组织磁化率（如洛伦兹球近似所示），而是取决于细胞水平上磁化率包涵体的分布和对称性。我们使用离体大鼠视神经作为模型系统，具有高度组织化的细胞结构，包含纵向排列的髓鞘和神经丝。神经的圆柱形可以精确测量其磁化率和局部频率偏移。我们发现神经与水的体积磁化率差异为- 0.116ppm，新鲜神经的纵向成分磁化率为- 0.043ppm，固定神经的纵向成分磁化率为- 0.020ppm。视神经的频移作为WM的代表与GLA一致，但与洛伦兹球近似不一致。
The nature of the remarkable phase contrast in high field gradient echo MRI studies of human brain is a subject of intense debates. The Generalized Lorentzian Approach (GLA) (He & Yablonskiy, PNAS 2009;106:13558) provides an explanation for the anisotropy of phase contrast, the near absence of phase contrast between WM and CSF, and changes of phase contrast in multiple sclerosis. In this study we experimentally validate the GLA. The GLA suggests that the local contribution to frequency shifts in WM does not depend on the average tissue magnetic susceptibility (as suggested by Lorentzian sphere approximation), but on the distribution and symmetry of magnetic susceptibility inclusions at the cellular level. We use ex vivo rat optic nerve as a model system of highly organized cellular structure containing longitudinally arranged myelin and neurofilaments. The nerve's cylindrical shape allowed accurate measurement of its magnetic susceptibility and local frequency shifts. We found that the volume magnetic susceptibility difference between nerve and water is −0.116ppm, and the magnetic susceptibilities of longitudinal components are −0.043ppm in fresh nerve, and −0.020ppm in fixed nerve. The frequency shift observed in the optic nerve as a representative of WM is consistent with GLA but inconsistent with Lorentzian sphere approximation.
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DOI：
10.1016/j.jmr.2009.10.005
发表时间：
2010-01
期刊：
Journal of magnetic resonance (San Diego, Calif. : 1997)
影响因子：
--
作者：
Luo J;He X;d'Avignon DA;Ackerman JJ;Yablonskiy DA
通讯作者：
Yablonskiy DA
影响因子：
5.7
作者：
Luo, Jie;Jagadeesan, Bharathi D.;Cross, Anne H.;Yablonskiy, Dmitriy A.
通讯作者：
Yablonskiy, Dmitriy A.
影响因子：
3.3
作者：
Sukstanskii, Alexander L.;Yablonskiy, Dmitriy A.
通讯作者：
Yablonskiy, Dmitriy A.
影响因子：
3.3
作者：
CHU, SCK;XU, Y;SPRINGER, CS
通讯作者：
SPRINGER, CS
影响因子：
2.5
作者：
BAKKER, CJG;MOERLAND, MA;BEERSMA, R
通讯作者：
BEERSMA, R