IMPORTANCE: The neonatal brain injury score on magnetic resonance imaging following moderate or severe hypoxic-ischemic encephalopathy developed by the National Institute of Child Health and Human Development Neonatal Research Network has been revised to separate watershed and basal ganglia or thalamic injury and their associated outcomes. OBJECTIVE: To evaluate the association of the injury score with outcomes of death or moderate or severe disability among all infants, and with neurodevelopment among survivors in a trial of deeper and longer cooling. DESIGN, SETTING, AND PARTICIPANTS: In this secondary analysis of a multicenter randomized clinical trial, brain imaging was obtained from infants between October 2010 and November 2013. Infants were followed up to 18 months of age, with follow-up completed in January 2016. Data analysis was performed from August 2021 to September 2024. INTERVENTIONS: Infants were assigned to 4 hypothermia groups based on depth and duration of cooling, stratified by center and level of encephalopathy in a 2 × 2 factorial design to cooling at 33.5 °C or 32.0 °C and to 72 or 120 hours. A 10-level brain injury score was examined. MAIN OUTCOMES AND MEASURES: The primary outcome was death or moderate or severe disability measured by the Bayley Scales of Infant and Toddler Development III, the Gross Motor Function Classification System level, vision, and hearing. RESULTS: This study included 298 infants who had magnetic resonance imaging (MRI) and primary outcome data among 364 infants of the initial cohort (mean [SD] age at MRI, 9.18 [4.49] days). Death or moderate or severe disability occurred in 72 of 298 infants (24%), and disability occurred in 52 of 278 surviving infants (19%). Death or disability occurred in 12 of 28 infants (43%) with any or predominant watershed injury and in 17 of 46 (37%) of those with any or predominant basal ganglia or thalamic injury. Among the 32 infants with hemispheric devastation, 30 (94%) had death or disability, and 17 (89%) survived with moderate or severe disability. Injury scores of increasing severity were associated with death or disability among all infants (odds ratio, 13.66 [95% CI, 7.47-24.95]
area under the curve, 0.84 [95% CI, 0.78-0.90]) and with disability among surviving infants (odds ratio, 10.52 [95% CI, 5.46-20.28]
area under the curve, 0.80 [95% CI, 0.73-0.88]). There were no differences in the injury score between infants undergoing usual care cooling and those cooled to a greater depth or longer duration. CONCLUSIONS: Among infants with hypoxic-ischemic encephalopathy, outcomes were similar between infants with watershed and basal ganglia injury. Higher imaging scores were associated with risk of death or disability among all infants and with neurodevelopmental disability among surviving infants. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01192776.