MRI assessment of myelination patterns in high-risk infants.

Magnetic resonance imaging (MRI) was used in high-risk infants to assess the myelination process and its relationship with neurologic outcome. The time period when delayed myelination is best detected by MRI was also studied. MRI was performed in 39 high-risk infants (i.e., preterm infants, infants with respiratory distress syndrome, or with neonatal convulsions and asphyxia). In 10 of 11 infants with normal development, MRI revealed a normal myelination pattern before 2 months of age, and in 11 of 13 infants after 2 months of age. Conversely, in infants with poor outcomes, MRI demonstrated delayed myelination patterns in only 1 of 4 infants before 2 months of age but in 9 of 11 infants after 2 months of age. In patients with poor outcomes, delayed myelination was found more frequently after rather than before 2 months of age. These findings demonstrate that delayed myelination detected by MRI is useful in predicting the neurologic outcome of high-risk infants, especially after 2 months of age.