Assessment of myelin and brain volumes at early school-age: long-term effects of a preterm birth

Introduction: Structural and functional alterations in white matter architecture are common described in children born preterm (PT) and associated to behavioral implications. Still, how critical gestational immaturity may associate with later myelination is less studied. This study aimed to explore the influence and associations between gestational age (GA) and birthweight (BW) in children born PT compared with fullterm (FT), on quantitative values of brain myelin and volumes. Patients and methods: Participants included 60 children (mean age = 8.2 years) categorized based on GA (weeks); ranging from 25 - 35.4 in PTs (N=27); 38 - 41.9 in FTs (N=33). Volumetric brain measures were conducted by a 3.0-Tesla MRI-scanner and synthetic MRI (SyMRI) acquisition sequence, including synthesis of contrast weighted images. Automatic segmentation of total brain tissues (intracranial [ICV] and parenchymal [BPV] volume [ml]) generated gray-matter (GM), white-matter (WM), cerebrospinal fluid (CSF), and total myelin volume. Result: Children born extremely PT (<27GW) displayed reductions of total BPV and WM compared to FTs, less myelinated content than very PT (VPT; < 32GW) and moderately PT (MPT; <36GW), and significant more CSF than FT-born. Significant positive correlation between respectively increasing GA (r= .48) and BW (r= .53) and amount of myelinated content were found for the PT-born. Conclusion: Detection of diversity regarding myelination and brain-volumes and associations to risk factors related to gestational immaturity may be useful for increased understanding of long-term effects of degree of prematurity and allowing future investigations of how interventions effects brain myelination (and plasticity) in children born PT.