A novel approach to investigate the impact of RF pulses on the BOLD contrast in steady-state pulse sequences

Introduction: Various mechanisms have recently been proposed to impact on the BOLD-contrast in steady-state sequences [1]. It has been speculated that magnetization transfer effects and/or relaxation during RF pulses, which are applied during a significant percentage of the imaging time, contribute to the detected signal changes. However, the investigation of various potential mechanisms has been hampered by the interaction of multiple effects. In this paper, we propose a novel acquisition and post processing approach, which allows adjusting pulse parameters independently in order to be able to systematically study various mechanisms, which potentially contribute to fMRI signal changes, such as relaxation during the pulse and magnetization transfer effects.