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.