Localized two-dimensional shift correlated spectroscopy in humans at 2 Tesla.

A method for the acquisition of localized 2D shift-correlated spectra, based on the combination of the stimulated-echo volume-selection and gradient-enhanced COSY experiments, is described. The sequence can be modified to perform a number of localized experiments including HOHAHA and DQF-COSY. The method is demonstrated in vivo by presentation of localized COSY and HOHAHA spectra of human tibia marrow, and a localized COSY spectrum of human brain acquired at a field strength of 2 Tesla. Cross peaks corresponding to correlations between coupled groups along the acyl chains of triglycerides are observed in the spectra of marrow. The major cerebral metabolites are represented in the in vivo COSY brain spectrum, including N-acetylaspartate, glutamate/glutamine, total creatine, aspartate, and myo-inositol. Difficulties in the implementation of localized shift-correlation spectroscopy, including water suppression and T2 relaxation, are discussed.