Characterization and correction of interpolation effects in the realignment of fMRI time series
Characterization and correction of interpolation effects in the realignment of fMRI time series
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DOI：
10.1006/nimg.1999.0515
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发表时间：
2000-01-01
期刊：
影响因子：
5.7
通讯作者：
Turner, R
中科院分区：
文献类型：
--
作者：
Grootoonk, S;Hutton, C;Turner, R
功能磁共振成像(FMRI)研究中的受试者运动可以使用重排算法准确地估计。然而，即使在图像时间序列重新对准之后，仍在数据中识别出由运动引起的信号强度的残余变化。这些伪影的性质是使用fMRI图像的模拟位移来表征的，并且归因于由重新对准中固有的重采样引入的内插误差。提出了一种校正方案，该方案使用估计的位移的周期函数来逐个体素地从图像时间序列中消除内插误差。使用脑模来研究伪影以避免生理上的混淆，小范围和大范围的系统位移表明伪影具有与模拟位移所揭示的相同的形式。一个随机移动的体模和一个人体对象被用来演示使用校正使内插误差最小化。(C)2000年学术出版社。
Subject motion in functional magnetic resonance imaging (fMRI) studies can be accurately estimated using realignment algorithms. However, residual changes in signal intensity arising from motion have been identified in the data even after realignment of the image time series. The nature of these artifacts is characterized using simulated displacements of an fMRI image and is attributed to interpolation errors introduced by the resampling inherent within realignment. A correction scheme that uses a periodic function of the estimated displacements to remove interpolation errors from the image time series on a voxel-by-voxel basis is proposed. The artifacts are investigated using a brain phantom to avoid physiological confounds Small- and large-scale systematic displacements show that the artifacts have the same form as revealed by the simulated displacements. A randomly displaced phantom and a human subject are used to demonstrate that interpolation errors are minimized using the correction. (C) 2000 Academic Press.