Graeme A. Keith1, Christopher T. Rodgers1, Aaron T. Hess1, Carl J. Snyder2, University of Minnesota University of Minnesota Vaughan2, Matthew D. Robson1
1Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, Oxfordshire, United Kingdom; 2Center for Magnetic Resonance Research, Minneapolis, MN, United States
A novel method for tuning and matching an eight channel cardiac RF array for parallel transmit at 7 Tesla is presented. Piezoelectric stepping motors were used to allow automation of the process and remove the need for tuning by hand. S11 profiles for each channel were gathered showing the ratio between reflected and forward power across all of 2-D tune/match space. For both a phantom and in vivo these plots show a clear peak where the maximum S11 occurs. Auto-tuning at 7T was used in vivo to quickly and effectively to maximise the B1+.