Cerebral magnetic resonance imaging of preterm infants after corrected age of one year.

A total of 17 very-low-birth-weight (range from 625-1500 grams) preterm infants received brain magnetic resonance imaging (MRI) study at a mean corrected age of 23 months (range from 15-33 months). They were classified into two groups. In Group 1 (12 cases) the cranial ultrasound study was normal during infancy. There were two cases with typical change of periventricular leukomalacia (PVL) detected by MRI study; both showed spastic diplegia. In Group 2 (five cases) ultrasound study was abnormal during infancy while the MRI confirmed the change of PVL in these cases whose ultrasound study showed typical change of PVL. In two cases of intraventricular hemorrhage (IVH) Grade I and III separately, the MRI also revealed the change of PVL, but only the case of IVH grade III had spastic diplegia. The myelination process of all cases were completed as normal term infants. In conclusion, brain MRI confirmed the PVL change discovered by cranial ultrasound and the results were strongly correlated with spastic type cerebral palsy. For those infants with an abnormal neurological examination, MRI may be useful for diagnosis of PVL in spite of normal ultrasound findings during the newborn period.