1Center for Environmental Measurement and Analysis, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
Maps of the transmission field B1t+ and the reception filed B1r- by a quadrature coil differ and show mirror symmetry in human brain at high field. This is similar to a feature in a linear coil. We analytically examined the source of this mirror symmetry in a quadrature coil. We found that B1t+ and B1r- differ in the sign of the sinusoidal phase difference. This relationship is similar to that in a linear coil. We also examined maps of magnitude and phase components in the laboratory frame computed from B1t+ and B1r- maps of human brains at 4.7 T.