3D LOCALIZED 2D NMR-SPECTROSCOPY ON AN MRI SCANNER

Three-dimensionally localized versions of several two-dimensional NMR sequences have been implemented on a 1.5 T whole-body MRI/MRS scanner. In addition to the localization of voxels, the slice-selective RF pulses were also used for refocusing/transfer of various coherences in the 2D NMR sequences. Initial phantom and in vivo human studies are presented here. The sequences were localized versions of 2D J-resolved, 2D zero-quantum, 2D double-quantum, zero-quantum-filtered COSY and SECSY, and double-quantum-filtered COSY and SECSY. Two-dimensional plots for the J-resolved and multiple-quantum sequences are presented for a phantom containing an aqueous solution of 10 mM alanine. Sensitivity of different multiple-quantum-coherence orders to B-0 inhomogeneity is discussed. Localized double-quantum-filtered COSY of a phantom containing physiological concentrations of several metabolites also is presented to demonstrate the feasibility of performing this technique within time limits reasonable for human comfort. The first-reported 2D J-resolved H-1 in vivo MR spectrum localized in three dimensions in presented here, acquired predominantly from the cerebral white matter of a healthy volunteer and demonstrating the use of localized 2D NMR techniques in vivo. (C) 1995 Academic Press, Inc.