Myelination of the central nervous system can be demonstrated with magnetic resonance imaging. The influence of periventricular-intraventricular hemorrhage and periventricular leukomalacia on cerebral myelination was studied using magnetic resonance imaging. The subjects were 33 preterm infants of less than 30 weeks' gestation studied at 44 weeks' postmenstrual age: 11 infants with periventricular-intraventricular hemorrhage, 7 with periventricular leukomalacia, and 15 without periventricular-intraventricular hemorrhage or periventricular leukomalacia VSports手机版. There were no differences in mean gestational age and birth weight between the three groups. However, infants without periventricular-intraventricular hemorrhage or periventricular leukomalacia had significantly less respiratory distress syndrome. At 44 weeks postmenstrual age, infants with periventricular leukomalacia had a significantly delayed myelination pattern (stage M2) in comparison with infants without periventricular-intraventricular hemorrhage or periventricular leukomalacia and infants with periventricular-intraventricular hemorrhage (stages M3 and M4). The latter two groups had myelination stages that were similar to those of healthy term infants at 44 weeks' postmenstrual age. The results demonstrate that periventricular leukomalacia causes delayed myelination of the cerebrum, whereas periventricular-intraventricular hemorrhage does not. .