Supplementary Material for: Brain MRI injury patterns across gestational age among preterm infants with perinatal asphyxia.

Introduction: Brain injury patterns of preterm infants with perinatal asphyxia (PA) are underreported. We aimed to explore brain magnetic resonance imaging (MRI) findings and associated neurodevelopmental outcome in these newborns.
Methods: Retrospective multicenter study including infants with gestational age (GA) 24.0-36.0 weeks and PA, defined as ≥2 of the following: 1) umbilical cord pH ≤7.00, 2) 5-minute Apgar ≤5, 3) fetal distress or systemic effects of PA. Findings were compared between GA <28.0 (group 1), 28.0-31.9 (group 2) and 32.0-36.0 weeks (group 3). Early MRI (<36 weeks postmenstrual age or <10 postnatal days) was categorized according to predominant injury pattern, and MRI around term-equivalent age (TEA, 36.0-44.0 weeks and ≥10 postnatal days) using the Kidokoro score. Adverse outcomes included death, cerebral palsy, epilepsy, severe hearing/visual impairment, or neurodevelopment <-1 SD at 18-24 months corrected age.
Results: One hundred nineteen infants with early MRI (n=94) and/or MRI around TEA (n=66) were included. Early MRI showed predominantly hemorrhagic injury in group 1 (56%) and 2 (45%), and white matter (WM)/watershed injury in group 3 (43%). Around TEA, WM scores were highest in group 2 and 3. DGM (aOR 15.0, 95% CI 3.8 – 58.9) and hemorrhagic injury on early MRI (aOR 2.5, 95% CI 1.3 – 4.6), and Kidokoro WM (aOR 1.3, 95% CI 1.0-1.6) and DGM sub-scores (aOR 4.8, 95% CI 1.1–21.7) around TEA were associated with adverse neurodevelopmental outcome.
Conclusion: The brain injury patterns following PA in preterm infants differ across GA. Particularly DGM abnormalities are associated with adverse neurodevelopmental outcomes.