Cerebral maturation in premature infants: Quantitative assessment using MRimaging

BACKGROUND AND PURPOSE: The assessment of whether brain development is at a n appropriate level for age has become an integral part of clinical MR repo rting, although few studies have quantitatively defined the developmental c hanges occurring in premature infants. We have developed a simple scoring s ystem to assess four parameters of cerebral maturation-myelination, cortica l folding, glial cell migration, and germinal matrix distribution-to determ ine the total maturation score (TMS). The aim of this study was to validate this scoring system in a large population of preterm infants across a rang e of gestational ages. METHODS: A retrospective analysis was conducted of MR images acquired over a 3-year period with an identical imaging protocol. Infants born more than 14 days before the imaging examination and those with a clinical or radiolo gic history suggestive of neuroabnormality were excluded from the study. Th e TMS was derived by consensus. Interobserver agreement was evaluated by us ing the Bland-Altman plot. RESULTS: Images from 134 infants (23-41 weeks' gestational age) were evalua ted. The TMS was significantly related to the postmenstrual age of the infa nt, with the mean TMS for each age group increasing with advancing postmens trual age. Interobserver agreement was found to be high (mean difference in score = 0.07, SD = 0.56). CONCLUSION: This scoring system provides a standardized method for assessin g cerebral maturation in the premature infant. The TMS is easy to calculate from standard MR images, is reproducible, and can help detect changes occu rring within a postnatal age of a few weeks.