Premature exposure to the extrauterine environment negatively affects the brains' developmental trajectory. Our aim was to determine whether extremely preterm (EPT) infants, with no evidence of focal brain lesions, show morphological brain differences when compared with term-born infants. Additionally, we investigated associations between perinatal factors and neuroanatomical alterations. Conventional magnetic resonance imaging was acquired at term-equivalent age (TEA) from 47 EPT infants born before 27 weeks of gestation, and 15 healthy, term-born controls. Automatic segmentation and voxel-based morphometry-Diffeomorphic Anatomical Registration through Exponentiated Lie algebra (DARTEL) were used. Compared with controls, EPT infants displayed global reductions in cortical and subcortical gray matter, brainstem, and an increased cerebrospinal fluid volume. Regionally, they showed decreased volumes of all brain tissues, in particular cortical gray matter. Increased volumes of cortical gray and white matter were observed in regions involved in visual processing. Increasing prematurity, intraventricular hemorrhage grade I-II, and patent ductus arteriosus ligation were associated with decreased volumes and had a particular effect on the cerebellum. Concluding, EPT infants without focal brain lesions had an altered brain growth at TEA that particularly affected the gray matter, and varied when it came to the presence of perinatal risk factors. Brain growth gains in EPT infants may be related to a longer extrauterine experience.
Keywords: brain growth; extremely preterm birth; perinatal risk factors; voxel-based morphometry.
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