TIME AND FREQUENCY-DOMAIN ANALYSIS OF NMR DATA COMPARED - AN APPLICATION TO 1D H-1 SPECTRA OF LIPOPROTEINS

A comparison between a time domain analysis algorithm (VARPRO) and a f requency domain analysis algorithm (FITPLA(C)) for parameter estimatio n of magnetic resonance spectroscopy (MRS) data series is presented. V ARPRO analyses the measured MRS signal (free induction decay; FID); FI TPLA(C) analyses the discrete Fourier transform of the FID, the freque ncy domain magnetic resonance spectrum. A rapid time domain method, us ed to subtract the dominating water resonance from a H-1 MRS FID, with out affecting the metabolites of interest, is outlined and applied. Al so a new ''pseudo-frequency selective'' approach to time domain fittin g is introduced. The possibilities of combining the most favorable fea tures of time and frequency domain processing into one single MRS sign al processing method are assessed. The H-1 MRS signals of ultracentrif uged very low (VLDL), intermediate (IDL), and high (HDL) density lipop rotein fractions from human blood plasma were used for the comparisons . The results from both algorithms were in good agreement.