Supplementary Material for: Supratentorial Brain Metrics Predict Neurodevelopmental Outcome in Very Preterm Infants without Brain Injury at Age 2 Years

Introduction: Very preterm infants are at risk for adverse neurodevelopmental outcome. To better identify children without brain injury at risk for developmental sequelae, we assessed predictive values of supratentorial brain metrics in relation to outcome. Methods: Very preterm infants underwent magnetic resonance imaging (MRI) at term-equivalent age. Infants with any grade of supra- or infratentorial brain injury according to Kidokoro et al. [Pediatrics 2014;134:e444–53] were excluded. Supratentorial brain metrics (biparietal width, extracerebral space, interhemispheric distance) were measured and categorised using existing cut-off values. The Psychomotor Developmental Index (PDI) and Mental Developmental Index (MDI) were assessed using the Bayley Scales of Infant Development, second and third edition, at 2 years of age. Developmental delay was defined as a score <85. Positive and negative predictive values for developmental delay were calculated. Results: A total of 237 very preterm infants were enrolled. Of all infants, 59 (21.2%) showed developmental delay. Infants with z-scores less than –0.5 for biparietal width had significantly lower PDI (p = 0.039) and MDI (p = 0.042) than infants with normal z-scores. Enlargement of extracerebral spaces was also related to lower PDI (p = 0.047) and MDI (p = 0.036). Negative predictive value was highest when all brain metrics were within the normal range (PDI <85: 96.6%, MDI <85: 90.0%). Combining the biparietal width and the interhemispheric distance showed highest positive predictive values for developmental delay (MDI or PDI <85: 58.3%). Discussion: Supratentorial brain metrics are predictive for neurodevelopmental outcome in infants with ostensibly normal MRI. A combination of supratentorial brain metrics is most meaningful for identifying infants at risk for long-term sequelae.