Early cerebral-metabolite quantification in perinatal hypoxic-ischaemic encephalopathy by proton and phosphorus magnetic resonance spectroscopy

Acute cerebral hypoxia-ischaemia, often due to birth asphyxia, is the major cause of perinatal brain injury. Phosphorus (31P) magnetic resonance spectroscopy (MRS) enables non-invasive monitoring of cerebral high-energy metabolites such as phosphocreatine (PCr) and nucleotide triphosphates (NTP; mainly adenosine triphosphate) and can evaluate hypoxic-ischaemic cerebral damage in the newbom.1,2 Following severe birth asphyxia, 31P spectra often appear normal for up to 24 h presumably due to apparent recovery of energy generation soon after the acute intrapartum insult. However, subsequent spectra often show reduced [ PCr] / [ inorganic phosphate (Pi)] : a measure of phosphorylation potential. In very severe cases, [NTP] eventually falls indicating impaired cerebral energy generation. This sequence of events has been termed “secondary energy failure” (SEF) .’ Proton (‘H) MRS has also been applied to studies of newborn brain enabling observation of choline-containing compounds (Cho) , total creatine (Cr) , N-acetylaspartate (Naa) and lactate (Lac) .3-5 Both 31P and ‘H spectra can be local&d to specific brain regions4s6 and metabolite concentrations can be quantitated.4~5~7*8 This report describes the early application of quantitative, local&d, ‘H and 31P MRS in severe perinatal hypoxic-ischaemic encephalopathy.