Use of voigt lineshape for Quantification of in vivo H-1 spectra

Quantification of NMR visible metabolites by spectral modeling usually assumes a Lorentzian or Gaussian lineshape, despite the fact that experimental lineshapes are neither, To minimize systematic fitting errors, a mixed Lorentzian-Gaussian (Voigt) lineshape model was developed, When tested with synthetic FIDs, the Voigt lineshape model gave more accurate results (maximum error 2%) than either Lorentzian (maximum error 20%) or Gaussian models (maximum error 12%), The three lineshape models gave substantially different peak areas in an in vitro experiment, with the Voigt model having a much lower chi(2) (2.1 compared with 5.2 for the Lorentzian model and 6.2 for the Gaussian model), In a group of 10 healthy volunteers, fitting of H-1 spectra from cerebral white matter gave significantly different peak areas between the methods, Even when area ratios were taken, the Lorentzian model gave higher values (+5% for NAA/choline and +2% for NAA/creatine) than the Voigt lineshape model, whereas the Gaussian model gave lower values (-2% and -1%, respectively).