Antoine Lutti1, Chloe Hutton1, Gunther Helms2, Jurgen Finsterbusch3, Nikolaus Weiskopf1
1Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, UK; 2MR-Research in Neurology and Psychiatry, Faculty of Medicine, University of Gttingen, Gttingen, Germany; 3Department of Systems Neuroscience, University Medical Center HamburgEppendorf, Hamburg, Germany
Inhomogeneities in the RF field (B1) lead to bias in quantitative imaging. We optimize three B1 mapping methods (dual-TR FLASH/AFI, SE/STE 3D EPI, 2D STEAM) in order to reduce the level of artefacts arising from inhomogeneities of the main static field (B0) and physiology in the resulting B1 maps. Our group study shows that flip angle maps obtained using the AFI and EPI methods are within 5% agreement and their stability is ~2% over repetitions across subjects. These optimized methods are therefore ideally suited for correction of B1 inhomogeneities in quantitative imaging at 3T.