Therapeutic hypothermia for neonatal hypoxic-ischemic encephalopathy: magnetic resonance imaging findings and neurological outcomes in a Brazilian cohort

Abstract

Objective: To determine the neurodevelopment outcomes after therapeutic hypothermia for neonatal hypoxic-ischemic encephalopathy (HIE) and identify the neonatal magnetic resonance imaging (MRI) findings associated with neurological outcome in a middle-income country.

Study design: All infants born after 35 completed weeks' gestation with signs of moderate to severe encephalopathy and evidence of perinatal asphyxia before 6 hours of life were submitted to whole-body hypothermia and were imaged at 18 ± 8.4 days of life (range 7-33 days) after birth. Surviving infants had the neurodevelopment outcome assessed at 12 to 18 months of age by trained professional masked to MRI findings.

Results: Forty-eight infants included, MRI scans were obtained from 34 infants; 14 (29.1%) patients died during hospitalization before MRI was performed. Nine (64.3%) of 14 patients were classified as severe encephalopathy presented Posterior Limb Internal Capsule (PLIC) sign at the MRI, 10 (71.4%) thalamus and basal ganglia (TBG) lesion, 9 (64.3%) white matter (WM) lesion, and 7 (50.0%) cortical lesion. Severe encephalopathy was associated with the motor delay at 12-18 months by Bayley III, Alberta Infant Motor Scale (AIMS), and Gross Motor Function Classification System (GMFCS) scores (p = .020, p = .048, p = .033, respectively), but not for the cognitive (p = .167) or language skills (p = .309). Lower BSID-III motor, cognitive, and language composite scores were associated with PLIC sign (p = .047; p = .006 and p = .003, respectively). TBG lesion (p = .051) and cortical lesion (p = .030) were associated with lower language composite score. Motor delay by AIMS and the presence of PLIC sign, TBG lesion, WM lesion, and Cortical lesion on MRI were observed (p < .001; p = .002; p = .001 and p = .027, respectively); as well as higher GMFCS score were associated with the presence of PLIC sign, TBG lesion, WM lesion, and Cortical lesion on MRI (p < .001; p = .001; p = .001, and p = .011, respectively).

Conclusions: Brain MRI in neonates with HIE after therapeutic hypothermia is a valuable tool for diagnosis of encephalopathy cerebral abnormalities and is an early predictor of outcome in infants treated with whole body hypothermia for HIE in the Brazilian experience.

Keywords: Neonates; hypoxic-ischemic encephalopathy; magnetic resonance imaging; neurodevelopmental outcome; therapeutic hypothermia.