Region-specific growth restriction of brain following preterm birth

Regional brain sizes of very-preterm infants at term-equivalent age differ from those of term-born peers, which have been linked with later cognitive impairments. However, dependence of regional brain volume loss on gestational age has not been studied in detail. To investigate the spatial pattern of brain growth in neonates without destructive brain lesions, head MRI of 189 neonates with a wide range of gestational age (24-42 weeks gestation) was assessed using simple metrics measurements. Dependence of MRI findings on gestational age at birth (Age(birth)) and the corrected age at MRI scan (Age(MRI)) were assessed. The head circumference was positively correlated with Age(MRI), but not Age(birth). The bi-parietal width, deep grey matter area and the trans-cerebellar diameter were positively correlated with both Age(birth) and Age(MRI). The callosal thickness (positive), atrial width of lateral ventricle (negative) and the inter-hemispheric distance (negative) were exclusively correlated with Age(birth). The callosal thickness and cerebral/cerebellar transverse diameters showed predominant dependence on Age(birth) over Age(MRI), suggesting that brain growth after preterm-birth was considerably restricted or even became negligible compared with that in utero. Such growth restriction after preterm birth may extensively affect relatively more matured infants, considering the linear relationships observed between brain sizes and Age(birth).