Aaron Oliver-Taylor1, Chris Randell2, Roger J. Ordidge3, David L. Thomas4
1Department of Medical Physics and Bioengineering, University College London, London, England, United Kingdom; 2PulseTeq Products Division, Renishaw PLC, United Kingdom; 3Centre for Neuroscience, University of Melbourne, Melbourne, Victoria, Australia; 4Institute of Neurology, University College London, London, England, United Kingdom
Presented is a method to acquire SAR maps of a pair of ASL labelling coils using proton resonance shift MR thermometry. Accurate SAR measurements can only be made from the linear initial temperature change when RF heating commences, however due to the low power of the ASL coils (1W) this temperature change is small and consequently suffers from low SNR. Regular EPI phase images were acquired over an extended period of RF heating, and the time series of each voxel fit to a suitable function to improve SNR. Resultant SAR maps are accurate and reproducible.