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Abstract #0950

High Precision Calibration of MRS Thermometry Using Validated Temperature Standards

Elena Vescovo1, Andrew Levick2, Sha Zhao1, Graham Machin2, Charmaine Childs3, Timothy Rainey3, Steve Williams1

1Imaging Science and Biomedical Engineering, The University of Manchester, Manchester, Greater Manchester, United Kingdom; 2Temperature Group, National Physical Laboratory, Teddington, Middlesex, United Kingdom; 3Brain Injury Research Group, The University of Manchester, Manchester, Greater Manchester, United Kingdom


Estimation of temperature by MRS from the chemical shift of water relative to N-acetylaspartate (NAA) relies on a calibration curve. To date these have never been related back to primary standards. We describe extremely stable temperature control of an MRS phantom at 1.5T using a circulating water bath and organic fixed-point materials, with measurements related back to the International Temperature Scale 1990 (ITS-90) at the UK National Physical Laboratory. Frequency differences (water-NAA) were highly reproducible (SD<10-4 ppm) at fixed temperature and R2 for the fit was 0.9996. Ionic strength affected the intercept but not slope of the temperature calibration.