The Mind Research Network, Albuquerque, NM 87106, United States.
J Neurosci Methods. 2011 Aug 15;199(2):363-9. doi: 10.1016/j.jneumeth.2011.05.018. Epub 2011 May 26.
BOLD fMRI is accepted as a noninvasive imaging modality for neuroimaging and brain mapping. A BOLD fMRI dataset consists of magnitude and phase components. Currently, only the magnitude is used for neuroimage analysis. In this paper, we show that the fMRI-magnitude-based neuroimage analysis may suffer two pitfalls: one is that the magnitude is non-negative and cannot differentiate positive from negative BOLD activity; the other is an edge effect that may manifest as an edge enhancement or a spatial interior dip artifact at a local uniform BOLD region. We demonstrate these pitfalls via numeric simulations using a BOLD fMRI model and also via a phantom experiment. We also propose a solution by making use of the fMRI phase image, the counterpart of the fMRI magnitude.
BOLD fMRI 被公认为神经影像学和脑图谱的一种非侵入性成像方式。BOLD fMRI 数据集由幅度和相位分量组成。目前，仅使用幅度进行神经影像分析。在本文中，我们表明，基于 fMRI 幅度的神经影像分析可能存在两个缺陷：一是幅度为非负，无法区分正性和负性 BOLD 活动；二是边缘效应，可能表现为局部均匀 BOLD 区域的边缘增强或空间内部凹陷伪影。我们通过使用 BOLD fMRI 模型进行数值模拟以及通过体模实验来证明这些缺陷。我们还通过利用 fMRI 相位图像（fMRI 幅度的对应物）提出了一种解决方案。
