Effect of Regularization Parameter and Scan Time on Crossing Fibers with Constrained Compressed Sensing.
Effect of Regularization Parameter and Scan Time on Crossing Fibers with Constrained Compressed Sensing.
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DOI：
10.1117/12.878382
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Prince JL
中科院分区：
文献类型：
--
作者：
Elshahaby FE;Landman BA;Prince JL
扩散张量成像（DTI）是一种MR成像技术，它使用一组扩散加权测量值来确定每个体素处的水扩散张量。在DTI中，在每个测量的体素处计算单个主导纤维取向，即使该体素内存在多个纤维群体。近年来提出了一种新的处理弥散加权磁共振数据的方法，称为体素内结构的交叉纤维角分辨（CFARI）。基于压缩感知，CFARI能够从有限数量的测量中解析体素内结构，但目前对其作为扫描和算法参数的函数的性能知之甚少。本文介绍了模拟实验，以帮助了解CFARI性能权衡的数据信噪比和算法正则化参数的函数。在压缩感知准则中，正则化参数β的选择是关键的。如果β太小，则解是传统的最小二乘解，而如果β太大，则解是零。β的正确选择是依赖于数据的，这意味着它也是空间变化的。在本文中，模拟使用两个随机张量具有不同的扩散率具有相同的分数各向异性，但不同的主特征值进行。结果表明，对于一个固定的扫描时间，重复测量的采集可以提高CFARI的性能和空间可变的，数据自适应正则化参数是有益的稳定结果。
Diffusion tensor imaging (DTI) is an MR imaging technique that uses a set of diffusion weighted measurements in order to determine the water diffusion tensor at each voxel. In DTI, a single dominant fiber orientation is calculated at each measured voxel, even if multiple populations of fibers are present within this voxel. A new approach called Crossing Fiber Angular Resolution of Intra-voxel structure (CFARI) for processing diffusion weighted magnetic resonance data has been recently introduced. Based on compressed sensing, CFARI is able to resolve intra-voxel structure from limited number of measurements, but its performance as a function of the scan and algorithm parameters is poorly understood at present. This paper describes simulation experiments to help understand CFARI performance tradeoffs as a function of the data signal-to-noise ratio and the algorithm regularization parameter. In the compressed sensing criterion, the choice of the regularization parameter beta is critical. If beta is too small, then the solution is the conventional least squares solution, while if beta is too large then the solution is identically zero. The correct selection of beta turns out to be data dependent, which means that it is also spatially varying. In this paper, simulations using two random tensors with different diffusivities having the same fractional anisotropy but with different principle eigenvalues are carried out. Results reveal that for a fixed scan time, acquisition of repeated measurements can improve CFARI performance and that a spatially variable, data adaptive regularization parameter is beneficial in stabilizing results.
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DOI：
10.1109/jstsp.2007.910971
发表时间：
2007-12-01
影响因子：
7.5
作者：
Kim, Seung-Jean;Koh, K.;Gorinevsky, Dimitry
通讯作者：
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影响因子：
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作者：
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影响因子：
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影响因子：
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作者：
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