Developmental features of the neonatal brain: MR imaging. Part I. Gray-white matter differentiation and myelination.

TLDR

Awareness of neonatal brain developmental features helps distinguish normal changes from pathology and enables earlier detection with MR imaging and CT. The study aimed to establish the normal appearance of the neonatal brain by imaging 51 infants aged 29–42 weeks postconception with a 0.6‑T MR scanner. T1‑weighted MR images were used to define stages of gray‑white matter differentiation and myelination in the neonatal brain. Gray‑white matter differentiation and myelination progressed in a predictable, cephalad pattern from 29 to 42 weeks postconception, with white matter intensity decreasing as brain water content fell, and delayed myelination was observed in nine infants with complicated perinatal courses.

Abstract

To establish the normal appearance of the neonatal brain, 51 neonates, 29-42 weeks postconception, underwent magnetic resonance (MR) imaging with a 0.6-T magnet in a prospective study. T1-weighted images were used to devise stages for the appearance of gray-white matter differentiation and extent of myelination. The results show that from 29 to 42 weeks postconception, changes in gray-white matter differentiation and myelination follow the stages in an orderly and predictable fashion. Changes in white matter intensity appear related to progressive decrease in brain water content. Myelination progresses cephalad from the brain stem at 29 weeks to reach the centrum semiovale by 42 weeks. Delayed myelination, defined as the absence of myelin in the corona radiata by 37 weeks, was seen in nine infants with complicated perinatal courses. Awareness of these developmental features should help to minimize misinterpretation of normal changes in the neonatal brain and lead to earlier detection of pathologic conditions, both with MR imaging and computed tomography.