Increased SNR & Activation in Hadamard-Encoded fMRI Through Physiological Noise Removal & Phase Correction

Alan Chu^1,2, Jon-Fredrik Nielsen¹, Scott J. Peltier¹, Douglas C. Noll¹

Hadamard-encoded fMRI is a multislice acquisition method that increases SNR. Because the method uses temporal filtering on complex data for subslice extraction, the method is more susceptible to physiological noise and phase fluctuations when compared with conventional fMRI, where only the magnitude is typically used for determination of voxel activation. In this work, we introduce both physiological noise removal and phase correction for Hadamard-encoded fMRI, and compare the resulting functional activation with that of a conventional fMRI scan.