Karen Julia Mullinger1, Winston X. Yan1, Takayuki Ohma1, Richard W. Bowtell1
1Sir Peter Mansfield Magnetic Resonance Center, School of Physics and Astronomy, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom
EEG data recorded simultaneously with fMRI acquisition are contaminated by large voltages generated by the time-varying magnetic field gradients. Here, we show that this gradient artefact (GA) can be reduced in magnitude by adjusting the subjects axial position in the scanner. Experiments carried out on four subjects show that the average GA produced by a multi-slice EPI acquisition can be reduced by 36% by moving the subject 4 cm towards the feet, starting with the nasion at iso-centre. A significant reduction in the residual gradient artefact after average artefact subtraction was also found with the subject at the optimal position.