On the averaging of cardiac diffusion tensor MRI data: the effect of distance function selection.
On the averaging of cardiac diffusion tensor MRI data: the effect of distance function selection.
复制标题
心脏弥散张量 MRI 数据的平均：距离函数选择的影响。
DOI：
10.1088/0031-9155/61/21/7765
复制
发表时间：
2016
影响因子：
3.5
通讯作者：
Gullberg,GrantT
中科院分区：
文献类型：
--
作者：
Giannakidis,Archontis;Melkus,Gerd;Yang,Guang;Gullberg,GrantT
扩散张量磁共振成像 (DT-MRI) 可以对高度定向组织的微观结构进行独特的洞察。为扩散张量空间选择最合适的距离函数对于增强这种成像方式的临床应用至关重要。多年来，文献中已经提出了线性和非线性度量。关于最合适的 DT-MRI 距离函数的争论仍在继续。在本文中，我们提出了一个框架，使用实际的高分辨率 DT-MRI 大鼠心脏数据来比较欧几里得、仿射不变黎曼和对数欧几里得度量。我们对来自五只大鼠心脏的三个连续且相同采集的 DT-MRI 数据集的扩散张量水平进行时间平均，作为纠正背景噪声引起的心肌细胞方向规律性损失的方法。该过程首次在张量距离函数选择的背景下应用。与之前使用不同的具体应用并置各种 DT-MRI 距离函数的研究相比，这项工作的独特之处在于它结合了以下内容：（i）通过定量而不是定性标准来判断指标，（ii）比较工具是无偏见的，（iii）在相同体素的基础上使用纵向比较操作。比较的统计分析表明，三种 DT-MRI 距离函数往往提供相同的结果。因此，我们得出的结论是，心脏 DT-MRI 研究的张量流形是一个曲率几乎为零的弯曲空间。通过模拟研究了操作的信噪比依赖性。最后，发现欧几里得平均后出现的“膨胀效应”太不重要，不值得考虑。
Diffusion tensor magnetic resonance imaging (DT-MRI) allows a unique insight into the microstructure of highly-directional tissues. The selection of the most proper distance function for the space of diffusion tensors is crucial in enhancing the clinical application of this imaging modality. Both linear and nonlinear metrics have been proposed in the literature over the years. The debate on the most appropriate DT-MRI distance function is still ongoing. In this paper, we presented a framework to compare the Euclidean, affine-invariant Riemannian and log-Euclidean metrics using actual high-resolution DT-MRI rat heart data. We employed temporal averaging at the diffusion tensor level of three consecutive and identically-acquired DT-MRI datasets from each of five rat hearts as a means to rectify the background noise-induced loss of myocyte directional regularity. This procedure is applied here for the first time in the context of tensor distance function selection. When compared with previous studies that used a different concrete application to juxtapose the various DT-MRI distance functions, this work is unique in that it combined the following:(i) metrics were judged by quantitative—rather than qualitative—criteria,(ii) the comparison tools were non-biased,(iii) a longitudinal comparison operation was used on a same-voxel basis. The statistical analyses of the comparison showed that the three DT-MRI distance functions tend to provide equivalent results. Hence, we came to the conclusion that the tensor manifold for cardiac DT-MRI studies is a curved space of almost zero curvature. The signal to noise ratio dependence of the operations was investigated through simulations. Finally, the'swelling effect'occurrence following Euclidean averaging was found to be too unimportant to be worth consideration.