Golam M. I. Chowdhury1, Graeme F. Mason1,
Kevin L. Behar1, Douglas L. Rothman1, Robin A. de Graaf1
1MRRC,
MR spectroscopy of the olfactory bulb is particularly
challenging due to its small size and proximity to bone and nasal cavities,
distorting field homogeneity with loss in sensitivity and resolution. Using
optimized shimming and adiabatic pulse sequences at 9.4 Tesla, we obtained
high quality 1H MR spectra of GABA (J-edited) and 1<sup>H-[
<sup>13<sup>C]-MRS of <sup>13<sup>C labeled
metabolites and measured the rates of glucose and acetate metabolism in
olfactory bulb. Metabolic fluxes were determined by fitting a
three-compartment metabolic model to time courses of 13C labeling of brain
glutamate and glutamine measured from rats OB receiving timed infusions of
[1,6-<sup>13<sup>C 2<sub>]glucose or [2-
<sup>13<sup>C]acetate.