The smoothing artifact of spatially constrained canonical correlation analysis in functional MRI.
The smoothing artifact of spatially constrained canonical correlation analysis in functional MRI.
复制标题
功能 MRI 中空间约束典型相关分析的平滑伪影。
DOI：
10.1155/2012/738283
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发表时间：
2012
影响因子：
7.6
通讯作者：
Nandy,Rajesh
中科院分区：
文献类型：
--
作者：
Cordes,Dietmar;Jin,Mingwu;Curran,Tim;Nandy,Rajesh
大量的研究表明，功能磁共振成像的多元统计方法的能力，以改善在嘈杂的环境中的大脑激活映射。一种先进的方法使用局部典型相关分析（CCA）来包含一组相邻体素，而不是查看单个体素时间过程。使用适当的检验统计量的值作为激活的度量。通常将值分配给中心体素;然而，这是一种方便的选择，并且没有约束会引入伪影，特别是在强局部激活的区域中。为了弥补这些不足，在CCA中引入了不同的空间约束，以加强中心体素的优势。然而，即使中心体素的优势条件得到满足，约束CCA仍然可以导致平滑伪影，通常被称为“CCA出血伪影”，在fMRI激活模式。本文介绍了一种新的方法来衡量和修正的平滑伪影约束CCA方法。结果表明，约束CCA方法校正平滑伪影导致更合理的激活模式，在功能磁共振成像显示使用数据从一个电机任务和记忆任务。
A wide range of studies show the capacity of multivariate statistical methods for fMRI to improve mapping of brain activations in a noisy environment. An advanced method uses local canonical correlation analysis (CCA) to encompass a group of neighboring voxels instead of looking at the single voxel time course. The value of a suitable test statistic is used as a measure of activation. It is customary to assign the value to the center voxel; however, this is a choice of convenience and without constraints introduces artifacts, especially in regions of strong localized activation. To compensate for these deficiencies, different spatial constraints in CCA have been introduced to enforce dominance of the center voxel. However, even if the dominance condition for the center voxel is satisfied, constrained CCA can still lead to a smoothing artifact, often called the “bleeding artifact of CCA”, in fMRI activation patterns. In this paper a new method is introduced to measure and correct for the smoothing artifact for constrained CCA methods. It is shown that constrained CCA methods corrected for the smoothing artifact lead to more plausible activation patterns in fMRI as shown using data from a motor task and a memory task.