In vivo proton spectroscopy without solvent suppression

In H-1 MR spectroscopy of the human brain, it is common practice to suppres s the solvent signal prior to acquisition. This reduces the large dynamic r ange which is otherwise required of the MR receiver and digitizer in order to detect the dilute metabolite resonances in the presence of the much larg er water signal. However, complete solvent suppression is not always obtain able, particularly over large volumes and in superficial regions containing large susceptibility gradients. In this work, it demonstrated that modern commercial MR scanners possess the dynamic range necessary to adequately re solve the 1H metabolites in unsuppressed spectra. Moreover, a postacquisiti on method is presented which can completely remove the intact water signal and accurately quantitate the metabolite peaks Preserving the water signal in in vivo spectroscopy has several useful benefits. such as providing a hi gh signal-to-noise ratio internal concentration, frequency. and line shape reference. Comparison is made between suppressed and unsuppressed spectra f rom both a phantom and the human brain acquired at 4 T (C) 2001 John Wiley G Sons, Inc.