Brain MRI Injury Patterns across Gestational Age among Preterm Infants with Perinatal Asphyxia

Abstract

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 outcomes in these newborns.

Methods: Retrospective multicenter study included infants with gestational age (GA) 24.0-36.0 weeks and PA, defined as ≥2 of the following: (1) umbilical cord pH ≤7.0, (2) 5-min Apgar score ≤5, and (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 groups 1 (56%) and 2 (45%), and white matter (WM)/watershed injury in group 3 (43%). Around TEA, WM scores were highest in groups 2 and 3. Deep gray matter (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 outcomes.

Conclusion: The brain injury patterns following PA in preterm infants differ across GA. Particularly DGM abnormalities are associated with adverse neurodevelopmental outcomes.

Keywords: Brain injury; Magnetic resonance imaging; Neonatal encephalopathy; Neurodevelopmental outcome; Perinatal asphyxia; Prematurity.

Fig. 1.

Examples of the main patterns of injury on early MRI on T2-weighted imaging (upper row) and diffusion-weighted imaging (lower row): a small hemorrhage in the right cerebellar hemisphere (a, e), an extensive intraventricular hemorrhage and diffusion-restriction of the deep WM (b, f), extensive diffusion restriction in the WM and posterior limb of the internal capsule (c, g), and diffusion restriction in the DGM with an intraventricular hemorrhage in the left ventricle (d, h).

Fig. 2.

Predominant pattern of injury on early MRI versus Kidokoro global brain injury scores for the infants with both early MRI and MRI around TEA, separately demonstrated for infants with a normal 18–24 month neurodevelopmental outcome (white diamonds) and infants with an adverse outcome (black diamonds). Kidokoro global brain abnormality scores were significantly higher (p < 0.001) in infants with an adverse outcome (median 11, IQR 7) compared to infants with a normal outcome (median 5, IQR 6).