Theoretical description of modern 1H in Vivo magnetic resonance spectroscopic pulse sequences

This article reviews the most commonly used modern sequences designed to confront the two major challenges of in vivo magnetic resonance spectroscopy (MRS): spatial localization and metabolic specificity. The purpose of this review article is to provide a deeper and clearer understanding of the underlying mechanisms by which all modern MRS sequences operate. A descriptive explanation, consistent pulse sequence diagram, and theoretical concepts of the measured signal are given for five spatial localization sequences and three modules designed to increase metabolic specificity. Cross-sequence comparisons, including potential modifications for estimating quantitative measures like spin-lattice relaxation time T-1, spin-spin relaxation time T-2, and diffusion coefficients are briefly discussed. Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;51:1008-1029.