LCModel and OSPREY GABA and Glu

Hello all,

I had a few questions regarding GABA and Glu Siemens Prisma-FIT 3 Tesla scanner, Glu is measured in ACC with a 2D echo-planar spectroscopic imaging (EPSI) slab (TR/TE=1700/20ms, 8 NEX, voxels 7.6x7.6x9 mm3). Water-suppressed and non-water-suppressed spectra are acquired. A single MEGA-PRESS58 (TR/TE=2000/68ms; 128 pairs of interleaved spectra with GABA editing pulse alternately on and off).

  1. To get the metabolite-to-water ratios (specifically GABA and Glu) in LCModel and OSPREY. For the CSI data, we collected both water-suppressed spectra and without-water-suppressed spectra. In LCModel and OSPREY, how do we quantify water if we collect a water reference scan? Is it automatically scaling or there’s another quantified value for water I need to pull?

  2. Also, where is the GABA+ for each in the output?

  3. Finally, do you have any resources that explain the difference between LCModel and OSPREY, specifically concerning GABA and Glu, and how to determine which software and ratio to use, or if one is better for different metabolites?

Thank you,