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Abstract #4444

B1 Inhomogeneity Mitigation in the Human Brain at 7T with Selective Pulses by using Average Hamiltonian Theory

Nicolas Boulant1, Martijn Cloos1, Alexis Amadon1

1NeuroSpin, CEA Saclay, Saclay, France

The design of the strongly modulating pulses, developed by the same authors and initially non-selective, has been adjusted to create selective pulses by using average Hamiltonian theory. Such a theory formulates an approximate analytical expression of the dynamics which allows navigating quickly in some pulse parameter space. Once a pulse is found to perform sufficiently well using that approximation, it can be modified with a few iterations by calculating more accurately the spin evolution. Using that technique, in-vivo results are reported which show good mitigation of the B1 inhomogeneity problem over an axial slice in the human brain at 7T.