Cerebral ischaemia studied by nuclear magnetic resonance spectroscopy

In this review, we assess the role of nuclear magnetic resonance (NMR) spectroscopy as a noninvasive method of studying metabolism in cerebral ischaemia. Phosphorus-31 NMR provides a monitor of intracellular pH and energy metabolites, including ATP, phosphocreatine, and inorganic phosphate, while other nuclei, including 1H, 13C, 19F, and 23Na can give additional information about several aspects of brain metabolism and physiology. For example, 1H NMR not only provides excellent images, but may also be used to monitor a range of metabolites, including lactate and several amino acids. Comparisons are made with the large body of information that is available from more traditional methods of studying metabolism. Emphasis is placed on the correlation of NMR data with parallel measurements of regional blood flow, tissue oxygenation, oedema, electrical activity, and tissue damage. Technical aspects of NMR are discussed where appropriate; for example, in relation to the range of metabolites that are accessible to study, the spatial resolution that is available for studies of focal lesions, problems arising from tissue heterogeneity, and quantification of metabolite levels. Applications in animal models and in humans are discussed; these primarily involve the 31P nucleus, but for the future it appears that 1H NMR studies offer particular promise.