Magnetic resonance spectroscopy (MRS) provides a non-invasive 'window' on biochemical processes within the body. Its use is no longer restricted to the field of research, with applications in clinical practice increasingly common. MRS can be conducted at high magnetic field strengths (typically 11-14 T) on body fluids, cell extracts and tissue samples, with new developments in whole-body magnetic resonance imaging (MRI) allowing clinical MRS at the end of a standard MRI examination, obtaining functional information in addition to anatomical information. We discuss the background physics the busy clinician needs to know before considering using the technique as an investigative tool. Some potential applications of hepatic and cerebral MRS in chronic liver disease are also discussed.
Keywords: CPMG, Carr-Purcell-Meiboom-Gill sequence; CSI, chemical shift imaging; FID, free induction decay; K, Kelvin; KEGG, Kyoto Encyclopedia for Genes and Genomes; MR, magnetic resonance; MRI, magnetic resonance imaging; MRS, magnetic resonance spectroscopy; MSEA, metabolite set enrichment analysis; NMR, nuclear magnetic resonance; NOESY, nuclear Overhauser enhancement spectroscopy; PC, principal components; PCA, principal components analysis; PLS-DA, partial least squared discriminant analysis; PRESS, point-resolved spectroscopy; STEAM, stimulated echo acquisition mode; T, Tesla; T1, spin-lattice relaxation; T2, spin-spin relaxation; TE, echo time; TMAO, trimethylamine N-oxide; TR, repetition time; magnetic resonance imaging; magnetic resonance spectroscopy; metabolomics; nuclear magnetic resonance.