Aim To compare antemortem cranial MRI with postmortem histopathological examination of the brain in full-term infants with neonatal encephalopathy following perinatal asphyxia.

Patients and methods In this retrospective observational cohort study, 23 infants with neonatal encephalopathy who subsequently died, were analysed. Infants underwent antemortem cranial MRI and postmortem histopathological examination of the brain. MRI included T1, T2 and diffusion-weighted sequences. Histopathology included staining with H&E, and monoclonal antibodies to CD68 and HLA-DR. Histological abnormalities were compared with MRI in 10 different brain regions.

Results All neonates underwent cranial MRI within 7 days after birth (median day 3, IQR 2–4 days). Infants died on median day 4 (IQR 2–5 days). Histopathology demonstrated significantly (p=0.0016) more abnormal regions (median 10, IQR 7–10) per patient than did MRI (median 8, IQR 5–9). The number of cases with abnormalities in the thalamus, basal ganglia, posterior limb of the internal capsule (PLIC), cerebral cortex and cerebellum were not significantly different between MRI and histopathology. By contrast, the hippocampus (70% vs 96%, p=0.047), cerebral white matter (anterior 65% vs 96%, p=0.022, posterior 61% vs 91%, p=0.035) and brainstem (57% vs 96%, p=0.004) were confirmed to be affected more often on histopathological examination than with MRI.

Conclusions Whereas early postnatal MR imaging is excellent in detecting injury to the basal ganglia and thalamus, PLIC, cortex and cerebellum, it may underestimate injury to the hippocampus, cerebral white matter, and the brainstem in term infants with neonatal encephalopathy following perinatal asphyxia.