Restoration of motion-related signal loss and line-shape deterioration of proton MR spectra using the residual water as intrinsic reference

Abstract

A postprocessing method to restore motion-related signal loss and line-shape deterioration in single-volume proton MR spectroscopy (MRS) is presented. Each acquisition is corrected by its phase offset and frequency shift, extracted from the residual water signal prior to averaging. Requirements are good gradient selection and selective suppression of CSF in residual water. Stimulated echo acquisition mode (STEAM) spectra (TE = 30 ms) were analyzed using the LCModel program to study gains in metabolite signal and spectral quality in five brain regions. Increases of total N-acetyl-aspartate concentrations of up to 5% were observed. The method may be beneficial for clinical examinations of less compliant subjects and for dynamic spectroscopy.