Towards compartment size estimation in vivo based on double wave vector diffusion weighting
Towards compartment size estimation in vivo based on double wave vector diffusion weighting
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DOI：
10.1002/nbm.1711
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发表时间：
2011-12-01
影响因子：
2.9
通讯作者：
Finsterbusch, Juergen
中科院分区：
文献类型：
--
作者：
Koch, Martin A.;Finsterbusch, Juergen
研究表明，双波矢量扩散加权，它采用两个独立方向的梯度脉冲对，可以提供有关组织结构的信息，否则不容易获得，如组织样本中的细胞大小或形状。测量细胞大小的一种方法是基于在两个扩散权重之间的小混合时间内平行和反平行梯度方向之间的信号差异。如果使用有限梯度硬件的临床MR系统，在体内应用的一个主要困难是信号差异的小尺寸。在本研究中，该方法应用于活体人脑组织，采用全身梯度。报告了皮质脊髓束的数据。观测信号在平行和反平行梯度方向上的差异特征与解析和数值预测一致。作为对孔隙大小的估计，由此得到的孔隙旋转半径的平方平均值约为4 μ m2。考虑梯度脉冲持续时间和扩散时间的有限值的分析得出，如果假设柱状孔隙形状，则体积贡献加权平均孔径为13 μ m。结果表明，该技术可以在体内应用。版权所有：John Wiley & Sons， Ltd。
It has been shown that double wave vector diffusion weighting, which employs two gradient pulse pairs of independent directions, can provide information about tissue structure that is not easily available otherwise, such as cell size or shape in a tissue sample. One approach to measure cell size is based on the signal difference between parallel and antiparallel gradient orientations at small mixing times between the two diffusion weightings. A major difficulty for in vivo application is the small size of the signal difference if clinical MR systems with limited gradient hardware are employed. In this study, the method is applied to human brain tissue in vivo, using whole-body gradients. Data are reported for the corticospinal tracts. The characteristics of the observed signal difference between parallel and antiparallel gradient orientations are consistent with both analytical and numerical predictions. As an estimate of pore size, the resulting mean squared radius of gyration of the pores amounts to approximately 4 mu m2. An analysis that accounts for the finite values of gradient pulse duration and diffusion time yields a volume contribution-weighted mean pore diameter of 13 mu m if a cylindrical pore shape is assumed. The results demonstrate that the technique can be applied in vivo. Copyright (C) 2011 John Wiley & Sons, Ltd.