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Abstract #4402

An Algorithm for Automatic Optimisation of Transmit Array Coil Tune and Match Applied in a Cardiac TEM Coil at 7T

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.