Periventricular hyperintensity detected by magnetic resonance imaging in infancy. Twenty-one infants younger than 12 months of age were diagnosed as having periventricular hyperintensity (PVH) on T2-weighted magnetic resonance imaging. Ten infants had experienced neonatal asphyxia, 6 intracranial hemorrhage, 2 bacterial meningitis, and 3 apnea. PVH was classified according to its extent. Round foci of PVH surrounding the frontal and occipital horns of the lateral ventricles were observed in 4 infants (PVH pattern I). Continuous PVH was observed in 17 infants (PVH patterns II and III). Fourteen infants with continuous PVH had spastic diplegia or quadriplegia. Developmental delay was demonstrated in 15 infants with continuous PVH. No PVH pattern I infants had cerebral palsy; only 1 such infant had mild developmental delay. Our study suggests that the extent of PVH reflects the severity of brain damage in neonates with cerebral injuries. 