MRI Findings in Infants With Infantile Spasms After Neonatal Hypoxic-Ischemic Encephalopathy

BACKGROUND: To evaluate the predominant pattern of brain injury and the anatomic areas of injury in children with infantile spasms following neonatal hypoxic-ischemic encephalopathy. METHODS: A nested case-control study of infantile spasms in children with term neonatal hypoxic-ischemic encephalopathy was performed. All patients had T1/T2-weighted magnetic resonance imaging with diffusion-weighted imaging performed on the third day of life. Using a validated scoring system, the magnetic resonance imaging was classified as: normal, watershed, basal ganglia/thalamus, total, or focal-multifocal. Two study investigators scored additional anatomic areas of injury (cortical extent, levels of the brainstem, hypothalamus) on T1/T2-weighted magnetic resonance imaging and diffusion-weighted imaging blinded to the outcome. The predominant pattern of brain injury and anatomic areas of injury were compared between patients who developed infantile spasms and randomly selected controls. RESULTS: Eight patients who developed infantile spasms were identified among a cohort of 176 term newborns with hypoxic-ischemic encephalopathy (4.5%). There were no significant differences in the perinatal and neonatal course between newborns who developed infantile spasms and controls who did not. The development of infantile spasms after neonatal hypoxic-ischemic encephalopathy was significantly associated with basal ganglia/thalamus and total brain injury (P ¼ 0.001), extent of cortical injury greater than 50% (odds ratio ¼ 11.7, 95% confidence interval ¼ 1.1-158.5, P ¼ 0.01), injury to the midbrain (odds ratio ¼ 13, 95% confidence interval ¼ 1.3-172, P ¼ 0.007) and hypothalamic abnormalities (P ¼ 0.01). CONCLUSIONS: The development of infantile spasms after hypoxic-ischemic encephalopathy is associated with injury to the basal ganglia and thalami on neonatal magnetic resonance imaging, particularly when extensive cortical injury and/or injury to the midbrain is present.