Christopher T. Rodgers1, Graeme A. Keith1, Aaron T. Hess2, Carl Snyder3, University of Minnesota University of Minnesota Vaughan3, Matthew D. Robson1
1Univ Oxford, Oxford, United Kingdom; 2University of Oxford, Oxford, United Kingdom; 3CMRR, Univ Minnesota, Minneapolis, MN, United States
7T body MRI requires transmit array coils. The popular TEM resonator design requires time consuming ~30min manual adjustments for each subject. This can be mechanised using piezo-actuators to drive the adjustment capacitors. We implement a system for monitoring coil RF characteristics in situ using RF pulses from the scanner. We characterise 4 potential optimisation metrics before introducing a simple, robust, efficient algorithm that automates coil tuning in less than 5 minutes. We close by explaining how auto-tuning may give not just faster, but actually superior coil tuning by optimising at isocentre and by monitoring power reflected through all RF channels.