Ozcan Alpay
Biomedical MR Laboratory, Mallinckrodt Institute of Radiology, Washington University in Saint Louis, School of Medicine, Box 8227, St. Louis, MO 63110, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2009;2009:2703-6. doi: 10.1109/IEMBS.2009.5332852.
A comprehensive, analytical framework for MR- DTI is constructed in a linear algebra setup. The expressions describing the effects of imaging gradients show formulation ambiguities. Center-symmetric gradient schemes use no cross terms (NoCroT) in the calculations resulting, at least in theory, in the alleviation of the issue. When three estimation methods, all gradients, NoCroT and diffusion gradients only are compared based on experimental results it is observed that the full inclusion of imaging gradients can be detrimental and there is slight improvement with NoCroT over diffusion gradients only. It is concluded that design of new diffusion gradient schemes via optimization is necessary to decouple to the maximum extent the effects of imaging gradients.
在一个线性代数设置中构建了一个用于磁共振扩散张量成像（MR-DTI）的全面分析框架。描述成像梯度效应的表达式存在公式模糊性。中心对称梯度方案在计算中不使用交叉项（NoCroT），至少在理论上，这会减轻该问题。当基于实验结果比较三种估计方法，即全梯度、NoCroT和仅扩散梯度时，发现完全包含成像梯度可能是有害的，并且NoCroT相对于仅扩散梯度有轻微改进。得出结论，通过优化设计新的扩散梯度方案对于最大程度地解耦成像梯度的影响是必要的。
