SEARCH

SEARCH BY CITATION

Keywords:

  • magnetic resonance spectroscopy;
  • proton MRS;
  • quantitation;
  • LCModel;
  • brain;
  • in vivo

Abstract

The LCModel method analyzes an in vivo spectrum as a Linear Combination of Model in vitro spectra from individual metabolite solutions. Complete model spectra, rather than individual resonances, are used in order to incorporate maximum prior information into the analysis. A nearly model-free constrained regularization method automatically accounts for the baseline and lineshape in vivo without imposing a restrictive parameterized form on them. LCModel is automatic (non-interactive) with no subjective input. Approximately maximum-likelihood estimates of the metabolite concentrations and their uncertainties (Cramér-Rao lower bounds) are obtained. LCModel analyses of spectra from users with fields from 1.5 to 9.4 T and a wide range of sequences, particularly with short TE, are used here to illustrate the capabilities and limitations of LCModel and proton MRS. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:
Ala

alanine

Asp

aspartate

Cr

creatine

GABA

γ-aminobutyric acid

Glc

glucose

Gln

glutamine

Glu

glutamate

GPC

glycerophosphocholine

GSH

glutathione

Ins

myo-inositol

Lac

lactate

NAA

N-acetylaspartate

NAAG

N-acetylaspartylglutamate

PC

phosphocholine

PCr

phosphocreatine

PE

phosphoethanolamine

Scyllo

scyllo-inositol

S/N

signal-to-noise ratio

Tau

taurine.