Patent ID: 8854039

Claim:
An MRI apparatus comprising: a magnetic resonance imaging (MRI) system having a plurality of gradient coils positioned about a bore of a magnet, and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly to acquire MR images; and a computer programmed to: execute an MR scan comprising an application of an RF pulse, an echo time (TE) period, and an application of a data acquisition gradient pulse, wherein the TE period begins after the RF pulse and ends before the data acquisition gradient pulse; acquire MR data of an imaging object during application of the data acquisition gradient pulse; reconstruct a phase image based on the acquired MR data; calculate a first contribution of phase to the phase image during the application of the RF pulse; calculate a second contribution of phase to the phase image during the application of the data acquisition gradient pulse; generate a frequency map based on the phase image and based on the first and second contributions of phase.