Neuroimaging Signatures of Neonatal Hypoxic-Ischaemic Encephalopathy and Their Predictive Value for Long-Term Neurodevelopmental Outcomes in South West Nigeria

Neonatal hypoxic-ischaemic encephalopathy (HIE) is a leading cause of childhood neurodisability in Nigeria, yet the relationship between early neuroimaging findings and long-term neurodevelopmental outcomes has not been characterised in a Nigerian clinical cohort. Therapeutic hypothermia, the standard of care for moderate-to-severe HIE in high-income settings, remains largely unavailable in Nigeria, making injury characterisation and outcome prediction from conventional brain imaging critical. This prospective longitudinal study enrolls neonates with confirmed HIE at University College Hospital Ibadan, Oyo State, South West Nigeria, and follows them to age three years. Brain MRI including diffusion-weighted imaging and proton magnetic resonance spectroscopy (1H-MRS) was performed at 5 to 7 days of life in 95 enrolled neonates with Sarnat stage II or III HIE. A standardised neuroimaging scoring protocol adapted for the Nigerian clinical context was applied. Primary outcome is composite neurodevelopmental impairment at age three, assessed using the Bayley-III and clinical neurological examination. Preliminary findings at two-year follow-up of the first 68 completed cases indicate that basal ganglia and thalamic signal abnormality on DWI at day five was the strongest single predictor of adverse neurodevelopmental outcome (OR 8.7, 95% CI 3.2-23.8). NAA/Cr ratio on MRS below 1.0 at the basal ganglia further stratified prognostic risk. A neuroimaging-based prediction model achieved an AUROC of 0.88 for adverse outcome prediction. This study pioneers HIE neuroimaging outcome research in sub-Saharan Africa and provides evidence for implementing structured MRI-based HIE prognostication in Nigerian tertiary centres. Keywords: HIE, neuroimaging, MRI, neurodevelopmental outcomes, South West Nigeria.