Rapid Brain Glutamate Mapping in Central and Peripheral Gray Matter at 3 and 4 Tesla using short TE Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI)
Posse S, Alger J, Chen H, Zuo C, Otazo R, Caprihan A, Bustillo J, Magnotta V, Renshaw P, Lim K, Ugurbil K, Mueller B, Gasparovic C
The MIND Institute, University of New Mexico School of Medicine
In this study we assess the reliability of mapping glutamate and other multiplet resonances at 3 and 4 Tesla across a whole brain slice that includes peripheral gray matter using the Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI) method. Glutamate maps displayed approximately two-fold concentration differences between white matter and central and peripheral gray matter areas, and mean Cramer-Rao lower bounds of 8 % across the entire slice. Smaller, but consistent gray /white matter differences were also seen in Cr maps. Mean CRLBs at 4 T in supra-ventricular slices were significantly smaller than at 3 T (p < 0.05, except Ala and Gln).