Real-Time Shim Feedback for Field Stabilization in Human MRI Systems

Y. Drst¹, B. J. Wilm¹, B. E. Dietrich¹, S. J. Vannesj¹, K. P. Pruessmann¹

Field changes stemming from various sources such as temperature drifts, physiological motion, or any other external effects can severely degrade results of MRI/MRS experiments. We implemented a real-time feedback system where NMR field probes are employed to measure magnetic field variations and actively compensate field changes using the shim coils of a whole-body. Successful field stabilization has been achieved in three experimental situations of varying effect strength, update rate, and spatial order of the field control.