Antoine Lutti1, Chloe Hutton1, Nikolaus Weiskopf1
1Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, UK
Spatial inhomogeneities in the radio-frequency field (B1) pose various problems such as spurious signal and contrast changes in MRI, leading to bias in quantitative imaging and difficulties in tissue segmentation. We optimize a 3D EPI B1 mapping method using carefully chosen RF pulses and a post-processing procedure that corrects biased flip angles and image distortions along the phase direction. We obtain reliable flip angle maps at 3T over the entire brain volume with a sufficient resolution and in an achievable experimental time.