Applications of magnetic resonance spectroscopy to chronic liver disease.

In vivo magnetic resonance spectroscopy (MRS) provides a non-invasive 'window' on biochemical processes within the body. The technique is currently a research tool, but new developments in whole-body magnetic resonance imaging (MRI) may provide a role for clinical MRS in obtaining functional information at the end of a standard MRI examination. Applications of hepatic and cerebral MRS to chronic liver disease and its associated complications are specifically considered in this article. Changes in phosphorus-31 MRS with the underlying functional severity of the cirrhotic liver are discussed. These reflect increased turnover of cell membranes as the liver attempts to regenerate. Patterns of spectral abnormality in the transplanted liver are described, and also the potential use of the technique to assess the viability of the stored donor liver in the time period between organ harvesting and implantation in the transplant recipient. Metabolite abnormalities in the brain are defined in hepatic encephalopathy and in patients infected with the hepatitis C virus who have minimal hepatic inflammation. Future trends are considered: for example, the use of MRS as a non-invasive tool to assess the effectiveness of liver-directed gene therapy.