BRAIN METABOLITE TRANSVERSE RELAXATION-TIMES IN MAGNETIC-RESONANCE SPECTROSCOPY INCREASE AS ADENOSINE-TRIPHOSPHATE DEPLETES DURING SECONDARY ENERGY FAILURE FOLLOWING ACUTE-HYPOXIA ISCHEMIA IN THE NEWBORN PIGLET

The adenosine triphosphate (ATP)-dependent sodium/potassium pump extrudes intracellular sodium in exchange for extracellular potassium. Low ATP causes pump dysfunction increasing both intracellular sodium and water thereby enhancing metabolite mobility. This should be detectable by proton magnetic resonance spectroscopy (MRS) as increased metabolite transverse relaxation times (T(2)s). During secondary cerebral energy failure in the newborn piglet, proton and phosphorus MRS showed large increases in the T(2)s of choline, creatine, N-acetylaspartate, and lactate that correlated with ATP depletion. These results provide insight into factors affecting metabolite T(2)s and show that T(2)s may be useful for studying cellular oedema.