Document Type

Article

Language

eng

Format of Original

10 p.

Publication Date

2-2012

Publisher

Elsevier

Source Publication

NeuroImage

Source ISSN

1053-8119

Original Item ID

doi: 10.1016/j.neuroimage.2011.09.082

Abstract

As more evidence is presented suggesting that the phase, as well as the magnitude, of functional MRI (fMRI) time series may contain important information and that there are theoretical drawbacks to modeling functional response in the magnitude alone, removing noise in the phase is becoming more important. Previous studies have shown that retrospective correction of noise from physiologic sources can remove significant phase variance and that dynamic main magnetic field correction and regression of estimated motion parameters also remove significant phase fluctuations. In this work, we investigate the performance of physiologic noise regression in a framework along with correction for dynamic main field fluctuations and motion regression. Our findings suggest that including physiologic regressors provides some benefit in terms of reduction in phase noise power, but it is small compared to the benefit of dynamic field corrections and use of estimated motion parameters as nuisance regressors. Additionally, we show that the use of all three techniques reduces phase variance substantially, removes undesirable spatial phase correlations and improves detection of the functional response in magnitude and phase.

Comments

Accepted version. NeuroImage, Vol. 59, No. 3, (Feb, 2012): 2231–2240. DOI. © 2012 Elsevier. Used with permission.

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