DETERMINATION OF PROTON METABOLITE CONCENTRATIONS AND RELAXATION PARAMETERS IN NORMAL HUMAN BRAIN AND INTRACRANIAL TUMORS

Quantitative proton spectroscopic studies were performed on 39 volunte ers and 16 patients with intracranial tumours, Estimates of T-2 were o btained in white matter, grey matter, cerebellum, astrocytomas and men ingiomas; T, was determined in white matter only, White matter values of T-1 for trimethylamines, creatine and N-acetyl aspartate (NAA) were 309 +/- 84, 195 +/- 41 and 369 +/- 124 ms, respectively (mean +/- SD, n = 20). Metabolite concentrations in white matter were 2.0 +/- 0.4 m u mol/g wet weight for trimethylamines, 7.3 +/- 1.1 for creatine and 1 1.4 +/- 1.4 for NAA. The mean concentrations of creatine and NAA in gr ey matter and all of three metabolites in cerebellum were greater than those in white matter. Tumour spectra were characterized by increased trimethylamines, reduced creatine and NAA and occasionally the presen ce of lactate, Meningiomas were further characterized by the presence of alanine, The mean T-2 and concentration of trimethylamines in tumou rs was significantly greater than in normal brain, Creatine and NAA co ncentrations were decreased in all tumours, The longer T-2 of trimethy lamines and presence of alanine in meningiomas indicate that important differences exist in membrane and glucose metabolism within these tum ours when compared to either astrocytomas or normal brain tissue.