Structural covariance in the cortex of very preterm adolescents: a voxel-based morphometry study

On the basis of findings in normative samples that different cortical brain regions covary in gray matter volume, most likely as a result of mutually trophic influences during cortical development, we aimed to study whether patterns of covariation in regional gray matter, i.e., structural covariance, differed between adolescents who were born very preterm and full-term controls. Optimized voxel-based morphometry was used to study structural magnetic resonance imaging scans from 218 very preterm adolescents (gestational age <33 weeks) and 127 controls at 14-15 years of age. Local gray matter volumes were obtained for 18 regions of interest involved in sensorimotor and higher-order cognitive functions. These were then used to predict local volumes in the remaining areas of the cortex, with total gray matter volume, age and gender used as confounding variables. Very preterm adolescents compared with controls demonstrated differential (i.e., both increased and decreased) structural covariance between medial, frontal and cingulate gyri, caudate nucleus, thalamus, primary visual cortex, cerebellum and several other cortical and subcortical regions of the cortex. These findings support previous research indicating that preterm birth is associated with altered cortical development, and suggest that developmental changes in one brain region may result in a cascade of alterations in multiple regions.