CSF Signal as a Complex-Valued RETROICOR Regressor Removes Unwanted Physiological Signal and Increases the Accuracy of Spatial Correlation in Complex-Valued fMRI
International Society for Magnetic Resonance in Medicine
Proceedings of the International Society for Magnetic Resonance in Medicine Scientific Meeting and Exhibition
Discarding the phase component of the time-series removes relevant biological information from a complex-valued signal. Although, commonly implemented retrospective image correction techniques fail to account for physiological artifacts in both the magnitude and phase components of the time-series. Using the CSF signal, observed during the data acquisition, as a complex-valued regressor increases the statistical power of fMRI analysis, through reducing unwanted physiological variability in the complex-valued signal of interest. The improved performance of implementing the complex-valued image correction methods is demonstrated with a comparison of magnitude-only and complex-valued spatial correlations.