Synthetic MRI demonstrates prolonged regional relaxation times in the brain of preterm born neonates with severe postnatal morbidity

•Early biomarkers are needed to identify preterm infants at risk for neurodevelopment impairment.•Synthetic MRI-based relaxometry is sensitive to age-related maturational changes.•Severe postnatal morbidity results in significantly prolonged regional tissue relaxation times.•Early myelinating structures appear to be more susceptible to brain injury.•Synthetic MRI may provide early prognostic biomarkers for neurodevelopment impairment.