Extracting a quality spectrum from the signal involves several processing steps:

  • Zero-filling or apodization filtering to complete the digitized FID signal
  • Phase correction to obtain the real part of the spectrum (absorption spectrum)
  • Baseline correction

In vivo metabolite quantification

  • Relative quantification: The results of the MRS are generally expressed as concentration ratios. Creatine peak or comparison with the healthy controlateral zone often serve as the reference values.
  • Absolute quantification: Measuring the true concentration of metabolites by MRS comes up against several technical difficulties: the peak area has to be determined accurately then converted into concentration after calibration.