Ozcan Alpay
Biomedical MR Laboratory, Mallinckrodt Institute of Radiology, Washington University in Saint Louis, School of Medicine, Box 8227, MO 63110, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2010;2010:2710-3. doi: 10.1109/IEMBS.2010.5626530.
The diffusion weighted MR signal is modeled using particle methods. The model shows that the signal is the Fourier transform of the distribution function of the number of spins at the initial time at a given position with a given displacement integral value. The distribution function is computed via Fourier transform steps that keep the Hermitian property of the signal in order to guarantee that the distribution function is real valued. The function, which depicts the tissue microstructure 'as it is' without being tied to any expansions, transformations and assumptions such as Markovian property or symmetry about the spin motions, is displayed using isosurfaces overlayed on the spin density map for a fixed baboon brain sample.
扩散加权磁共振信号采用粒子方法进行建模。该模型表明，信号是在给定位置具有给定位移积分值的初始时刻自旋数分布函数的傅里叶变换。分布函数通过傅里叶变换步骤计算得出，这些步骤保持信号的厄米特性，以确保分布函数为实值。对于一个固定的狒狒脑样本，该函数描绘了“真实的”组织微观结构，而不依赖于任何诸如马尔可夫性质或自旋运动对称性等扩展、变换和假设，通过叠加在自旋密度图上的等值面来显示。
