Volumetric differences in the brain in children with hypoxic-ischemic encephalopathy after therapeutic hypothermia: a review of MRI findings

Hypoxic-ischemic encephalopathy (HIE) remains a leading cause of neonatal brain injury, often resulting in long-term neurodevelopmental impairment. Therapeutic hypothermia (TH) is currently the only evidence-based treatment for HIE. This review summarizes volumetric magnetic resonance imaging (MRI) findings in children with HIE treated with TH. Across multiple studies, the hippocampus, thalamus, cerebellum, and basal ganglia consistently exhibit reduced volumes compared to healthy controls, though the statistical significance of these differences varies. Hippocampal volume reductions are observed in the neonatal period and later childhood, and are associated with poorer memory and cognitive outcomes. Thalamic and basal ganglia volumes are lower from the neonatal period through later childhood. Reduced thalamic volume is associated with impairments in cognitive and motor function. Cerebellar volume findings are inconsistent. Interpretation of volumetric differences remains challenging due to methodological heterogeneity across studies. Future studies are needed to validate volumetric biomarkers and establish normative data, facilitating the integration of volumetric MRI into early diagnostic and therapeutic strategies for children with HIE.