B0 METHOD TO DETERMINE A B0 FIELD MAP WITH A MAGNETIC RESONANCE DEVICE AND MAGNETIC RESONANCE DEVICE

摘要

The present invention relates to a method for determining a B0 field map describing a local deviation of a magnetic resonance apparatus (6) from a nominal Ramey frequency, characterized in that it comprises two Magnetic resonance data are acquired at two or more different phase relaxation times in measurements performed at different echo times 2 and 3 and measurements of the B0 field map from differences in measured phases at different echo times 2, The phase changes to be used for different phase relaxation times are determined and the phase changes of the different phase relaxation times are evaluated to at least partially reduce ambiguity due to Nyquist phase wrapping, And are executed by exciters that generate different excitation fields.