Optimized diffusion-weighted spectroscopy for measuring brain glutamate apparent diffusion coefficient on a whole-body MR system

NMR Biomed. 2005 Dec;18(8):527-33. doi: 10.1002/nbm.985.

Abstract

A diffusion-weighted stimulated echo acquisition mode sequence was implemented in order to measure the glutamate apparent diffusion coefficient (ADC) in the monkey brain on a whole-body 3 T system. TE and TM were adjusted for maximizing glutamate signal intensity. Glutamate ADC was measured in a 5.8 mL voxel made of gray and white matter in macaque monkeys. The effect of post-processing on the estimated ADC was carefully assessed and appeared to be critical. Individual scan phasing and macromolecule subtraction corrected for approximately 25% and approximately 15% biases in glutamate ADC, respectively. Proper data processing yielded ADC values of 0.21 +/- 0.03 microm(2)/ms for glutamate, 0.15 +/- 0.04 microm(2)/ms for N-acetylaspartate + N-acetylaspartylglutamate, 0.12 +/- 0.03 microm(2)/ms for creatine, 0.11 +/- 0.05 microm(2)/ms for choline and 0.18 +/- 0.04 microm(2)/ms for myo-inositol.

MeSH terms

  • Animals
  • Aspartic Acid / analogs & derivatives
  • Aspartic Acid / metabolism
  • Brain / anatomy & histology
  • Brain / metabolism*
  • Brain Chemistry
  • Choline / metabolism
  • Creatine / metabolism
  • Diffusion
  • Diffusion Magnetic Resonance Imaging*
  • Glutamic Acid / chemistry
  • Glutamic Acid / metabolism*
  • Humans
  • Inositol / metabolism
  • Macaca

Substances

  • Aspartic Acid
  • Glutamic Acid
  • Inositol
  • N-acetylaspartate
  • Creatine
  • Choline