LOCALIZED 2D J-RESOLVED H-1 MR SPECTROSCOPY - STRONG-COUPLING EFFECTSIN-VITRO AND IN-VIVO

A two-dimensional (2D) J-resolved MR spectroscopy sequence (2D J-PRESS ), fully localized in three dimensions, has been implemented on a whol e-body MR scanner. A modified PRESS sequence with [90 degrees-180 degr ees-t(1)/2-180 degrees-t(1)/2-acquisition] was used for voxel localiza tion. An incremental delay (t(1)/2) was added to the intervals before and after the last slice-selective 180 degrees RF pulse to monitor the J-evolution in a localized 2D MR spectrum. Spectra were recorded with phantoms containing common cerebral metabolites-alanine, N-acetyl asp artate, glutamine, glutamate, taurine, myo-inositol, glucose, aspartat e, GABA, and choline at 50 mM. In conformity with previously reported results, additional cross-peaks due to strong coupling were monitored in many metabolites. A brain phantom was developed to mimic the gray m atter of human brain with the metabolites at physiological concentrati ons (0.5-12 mM). In vivo 2D J-PRESS spectra (n = 18) of healthy human brain were in conformity with those recorded from the brain phantom.