Automatic quantitation of localized in vivo 1H spectra with LCModel.
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.
Provencher
S W
SW
Max Planck Institute for Biophysical Chemistry, D-37070 Göttingen, Germany. sp@s-provencher.com
D000465:Algorithms; D000818:Animals; D001923:Brain Chemistry; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D051381:Rats; D012815:Signal Processing, Computer-Assisted; D012984:Software