Study cohort
HIE, brain injury, encephalopathy
MRS, ENCEPHALOPATHY
Among 500 infants with presumed HIE who were participants in HEAL, the severity of encephalopathy was moderate in 77% and severe in 23%. A total of 474 (95%) infants received a brain MRI prior to discharge. The characteristics of infants with and without brain MRI were similar, except that infants without neuroimaging were more likely to have severe HIE (12/26, 46% vs. 101/474, 21%, The final study cohort consisted of 451 infants who had an interpretable MRI study and a primary outcome at 2 years of age. The median age at neuroimaging was 5.0 days (IQR 4.5–5.8). Among infants in the study cohort, we assessed the acuity of brain injury in 408 (91%) infants who received an MRI prior to 8 days of age. We calculated MRS ratios in infants who had spectra of sufficient quality for analysis within the thalamus (About half (51%) of the study cohort had a normal neurodevelopmental outcome at age 2 years, while the remaining infants had mild (12%), moderate (14%), or severe (13%) NDI or died (9%). The median MRI brain injury score was 8 (IQR 2–22). The severity of the brain injury seen on MRI ranged from none (21%) to mild (37%), moderate (21%), and severe (21%) injury.