A Novel Approach to Investigate the Impact of RF Pulses on the BOLD Contrast in Steady-State Pulse Sequences

Ute Goerke¹, Kamil Ugurbil¹

In recent research efforts, fMRI contrast in steady-state sequence has been investigated. Potential contributions to the fMRI signal changes in these sequences, in which a large fraction of the imaging time is used for excitation pulse, include magnetization transfer effects and/or relaxation during RF pulses. In this paper, we propose a novel approach using non-slice selective spoiled 3D GRE with chirp pulse excitation and multiple echo acquisition. Activation maps are obtained from the undersampled fMRI signal changes using the spectral side band analysis (SSBA). Initial results indicate differences in amplitude of the fMRI signal change depending on pulse bandwidth.