扩散取向分布函数的分辨率
Resolving power for the diffusion orientation distribution function.
作者信息
Jensen Jens H, Helpern Joseph A
机构信息
Center for Biomedical Imaging, Medical University of South Carolina, Charleston, South Carolina, USA.
Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina, USA.
出版信息
Magn Reson Med. 2016 Aug;76(2):679-88. doi: 10.1002/mrm.25900. Epub 2015 Oct 7.
PURPOSE
The diffusion orientation distribution function (dODF) is primarily used for white matter fiber tractography. Here the resolving power of the dODF is investigated for a simple diffusion model of two intersecting axonal fiber bundles.
METHODS
The resolving power for the dODF is evaluated using the Sparrow criterion. This is determined for the exact dODF and also for q-space imaging (QSI), q-ball, and kurtosis approximations.
RESULTS
Based on theoretical and numerical calculations, the resolving power is found to depend on the eigenvalues of the diffusion model and on the degree of radial weighting for the dODF. The resolving powers of the QSI and q-ball dODFs improve with increased b-value. The kurtosis dODF has a resolving power similar to that of the exact dODF.
CONCLUSION
The dODFs, whether exact or approximate, have finite resolving powers that limit their sensitivity to fiber crossings. The resolving powers for the different dODFs considered here provide convenient benchmarks for assessing and comparing their performance. Magn Reson Med 76:679-688, 2016. © 2015 Wiley Periodicals, Inc.
目的
扩散取向分布函数（dODF）主要用于白质纤维束成像。本文针对两个相交轴突纤维束的简单扩散模型，研究了dODF的分辨能力。
方法
使用Sparrow准则评估dODF的分辨能力。分别针对精确的dODF以及q空间成像（QSI）、q球和峰度近似进行了确定。
结果
基于理论和数值计算，发现分辨能力取决于扩散模型的特征值以及dODF的径向加权程度。QSI和q球dODF的分辨能力随着b值的增加而提高。峰度dODF的分辨能力与精确dODF相似。
结论
精确或近似的dODF都具有有限的分辨能力，这限制了它们对纤维交叉的敏感度。本文所考虑的不同dODF的分辨能力为评估和比较它们的性能提供了便利的基准。《磁共振医学》76:679 - 688，2016年。© 2015威利期刊公司。
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