Changho Choi1,
Aditya Patel1, Deborah Douglas1, Ivan Dimitrov1,2
1Advanced Imaging Research Center,
University of Texas Southwestern Medical Center, Dallas, TX, United States; 2Philips
Medical Systems, Cleveland, OH, United States
Proton
T2 measurement and quantification of brain coupled-spin metabolites in the
human brain, at 3T, is reported. Four pairs of PRESS (point resolved
spectroscopy) subecho times, which were obtained with numerical analyses of
the sequence for optimal separation between glutamate (Glu) and glutamine
(Gln), were used for T2 measurement. Single-voxel measurements were carried
out on the occipital cortex of five healthy volunteers. Spectra were analyzed
with LCModel fitting. From monoexponential fitting of the LCModel estimates
at the selected TEs, apparent T2s of Glu, Gln, and myo-inositol (mIns)
were measured to be 160 - 170 ms. Further, the signal strengths measured with
TR = 8 s were extrapolated to zero TE using the estimated T2 values. The
concentration ratio with respect to creatine was estimated to be 8.21.3,
4.60.6, 9.50.8, and 1.10.1 (meanSD, N = 5) for Glu, mIns, NAA, and
GPC+PC, respectively.