Ruth L. O'Gorman1,2, Jonathan Noble3, James M. Stone4, David J. Lythgoe5, Mary A. McLean6, Fahmida A. Chowdhury7, Philip K. McGuire4, Mark P. Richardson7, Gareth J. Barker5
1Neuroradiology, King's College Hospital, London, United Kingdom; 2MR-Zentrum, University Children's Hospital, Zurich, Switzerland; 3Medical Engineering and Physics, King's College Hospital, London, United Kingdom; 4Psychological Medicine and Psychiatry, Institute of Psychiatry, London, United Kingdom; 5Centre for Neuroimaging Sciences, Institute of Psychiatry, London, United Kingdom; 6Institute of Neurology, London, United Kingdom; 7Epilepsy Research Group, Institute of Psychiatry, London, United Kingdom
This study investigated the precision of glutamate (Glu) measurements for a PRESS protocol optimised for Glu/Gln separation (echo time (TE) =80 ms) and a standard short TE (30 ms) PRESS protocol, quantified using both frequency domain and time domain analysis methods. The longer TE improved Glu precision when time-domain fitting methods (AMARES/jMRUI) were used for quantitation, but offered little improvement when frequency-domain methods (LCModel) were used. The TE80 spectra processed with jMRUI offered the best precision for NAA and Choline, while the TE30 spectra processed with LCModel offered the best precision for Glu and Cr.