Hyperpolarized 13c magnetic resonance imaging after neonatal hypoxia-ischemia and therapeutic hypothermia; a newborn piglet model

Background and aims:Biomarkers of brain injury are needed for accurate prognosis and early evaluation of neuroprotective interventions in newborns with hypoxic ischemic encephalopathy (HIE). Hyperpolarized 13C MRI is a novel method to quantify metabolism in vivo with unprecedented resolution. We have previously shown that 13C MRI can quantify changes in cerebral metabolic phenotype in the acute phase after a hypoxic-ischemic (HI) insult in piglets. In this study we aimed to apply 13C MRI to investigate the metabolic phenotype in piglets subjected to a standardised HI insult and treated with therapeutic hypothermia (TH) compared to supportive care only.Methods:16 piglets were anesthetised, subjected to a HI insult, and randomized to treatment with TH (n = 8) or supportive care only (n = 8). Imaging was performed approximately 44 hours after the insult in a 3T MR scanner followed by acquisition of cerebral tissue for histological analysis. For 13C studies, [1-13C] pyruvate was hyperpolarized in a clinical polarizer. Following intravenous injection (6 mL of 125 mM isotonic pyruvate solution), rapid interleaved spectroscopic images were acquired using a spectral-spatial spiral imaging sequence. Metabolism of pyruvate to its metabolic products lactate, bicarbonate, and alanine will be reported as the accumulated signal of each metabolite proportional to the sum of all three metabolites. The 13C MRI metabolic patterns will be compared to conventional 1H MRI/MRS data and cell death measured through TUNEL staining on histological samples. Results:Pending.Conclusion:Experiments was finished in March of 2022. 13C MRI data analysis will be performed in May and results will be presented at EAPS conference in October.