MR FEATURES OF DEVELOPING PERIVENTRICULAR WHITE-MATTER IN PRETERM INFANTS - EVIDENCE OF GLIAL-CELL MIGRATION

PURPOSE: MR imaging of the brain is increasingly used in the investiga tion of the newborn, but little information is available on the normal appearance of the developing brain, We scanned a series of newborn in fants in an attempt to define the normal appearance of developing peri ventricular white matter and to assess how pathologic conditions may m odify this appearance. METHODS: Sixty-eight newborn infants, median po stmenstrual age (PMA) 34 weeks (range, 24 to 42 weeks), were subdivide d into two groups: group A (n = 33), which included those with normal clinical and sonographic examinations, and group B (n = 35), which con tained those with evidence of neuroabnormality detected prior to the M R study, either clinically or by cerebral sonography, Images were acqu ired in two planes on a 1.5-T imager using turbo spin-echo pulse seque nces. RESULTS: Symmetric periventricular bands of reduced signal inten sity were noted in the frontal periventricular white matter on T2-weig hted images in 98% of group A infants and in 97% of group B infants. T he number of bands was inversely related to PMA. The reduction in numb er of bands with increasing PMA was delayed in group B infants. CONCLU SION: The uniform appearance of periventricular bands in a population of healthy infants and their relationship to the infants' maturity is consistent with the results of previous histologic studies. These stud ies demonstrate the presence of migrating glial cells within the periv entricular white matter of infants beyond 20 weeks' gestation, when ne uronal migration to the cortex is complete. We postulate that the band s seen on T2-weighted images represent groups of migrating glial cells , providing a further marker of cerebral maturation.