Application of multiple inversion recovery for suppression of macromolecule resonances in short echo time H-1 NMR spectroscopy of human brain

Macromolecules contribute broad "background" resonances to the H-1 NMR brai n spectra at short echo times. The application of long echo times is the mo st widely used method for removing these resonances. Here, it is demonstrat ed that these background resonances may be suppressed at short echo times u sing multiple inversion recovery (MIR). In the technique presented, the MIR sequence consists of four adiabatic inversion pulses, applied preparatory to a 20-ms echo time stimulated echo localization sequence. The inversion t imes (359, 157, 69, and 20 ms) were selected to preferentially suppress mac romolecules with longitudinal relaxation times between 38 and 300 ms. While the resulting spectra have lower overall signal-to-noise, baseline contrib utions from macromolecules are greatly reduced. Unlike the typical long TE acquisitions, the short TE MIR acquisition preserves the myoinositol resona nce. (C) 1999 Academic Press.