MR spectroscopy in stroke

Magnetic resonance spectroscopy (MRS) is a non-invasive in vivo method that allows the investigation of biochemical changes in both animals and humans . The application of MRS to the study of stroke has made possible dynamic s tudies of intracellular metabolism of cerebral ischaemia. The majority of t he stroke studies have been carried out using proton [H-1]-MRS which allows the detection of N-acetyl aspartate (NAA), a neuronal marker. [H-1]-MRS ch anges in humans demonstrate that after an infarct, lactate appears, while N AA and total creatine are reduced compared to the contralateral hemisphere. Longitudinal studies demonstrate a further reduction of NAA suggesting tha t ischaemic injury continues for more than a week following infarction. Major advances in the treatment of acute stroke require the accurate predic tion of the mortality of stroke patients. Patients with large infarcts are known to do badly. In patients with small infarcts, less than 80 cm(3), the addition of core NAA concentrations and cerebral blood flow have enabled t he identification of some of the patients likely to benefit from new drug t reatment.