Improved proton spectroscopic U-FLARE imaging for the detection of coupledresonances in the rat brain in vivo

Modifications of the pulse sequence for spectroscopic U-FLARE imaging are d iscussed to detect not only the predominant singlet signals of N-acetylaspa rtate, total creatine, and choline containing compounds or the doublet sign al of lactate, but also the coupled resonances of glutamate, glutamine, tau rine and myo-inositol. Effective homonuclear decoupling is achieved by use of constant time chemical shift encoding. A maximum signal-to-noise ratio ( SNR) can be obtained for a certain coupled resonance of interest by optimiz ing the evolution period t(c) of the J modulated spin echo. Good reproducib ility and a high SNR were achieved by combining several methods for water s uppression and by using the displaced variant of U-FLARE. Measurements of a 3 mm slice of the rat brain were performed in vivo within 4 min, giving a nominal voxel size of 1.5 x 1.5 x 3.0 mm(3) or 1.5 x 0.75 x 3.0 mm(3). Thus , optimized spectroscopic U-FLARE is a powerful tool for proton spectroscop ic imaging with high spectral, spatial and temporal resolution. (C) 1999 El sevier Science Inc.