Dynamic Shimset Calibration for Bo Offset

摘要

A magnetic resonance imaging scanner includes a main magnet ( 20 ) generating a main B₀ magnetic field, one or more shim coils ( 60 ) selectively shimming the main B₀ magnetic field at selected shim currents, and a processor ( 70 ) executing a process including determining a magnitude shift of the main B₀ magnetic field responsive to the selective shimming and performing a correction during the energizing to correct for the determined magnitude shift of the main B₀ magnetic field. The performed correction includes one of (i) selectively energizing a D.C. shim coil ( 82 ) to counteract the determined magnitude shift of the main B₀ magnetic field and (ii) computing a magnetic resonance frequency corresponding to the main B₀ magnetic field including the determined magnitude shift and tuning a radio frequency transceiver ( 44, 46 ) to the computed magnetic resonance frequency.