title: Regional brain development in serial magnetic resonance imaging of low-risk preterm infants.
abstract: OBJECTIVE
  MRI studies have shown that preterm infants with brain injury have altered brain tissue volumes. Investigation of preterm infants without brain injury offers the opportunity to define the influence of early birth on brain development and provide normative data to assess effects of adverse conditions on the preterm brain. In this study, we investigated serial MRI of low-risk preterm infants with the aim to identify regions of altered brain development.
  
  
  METHODS
  Twenty-three preterm infants appropriate for gestational age without magnetic resonance-visible brain injury underwent MRI twice at 32 and at 42 weeks' postmenstrual age. Fifteen term infants were scanned 2 weeks after birth. Brain tissue classification and parcellation were conducted to allow comparison of regional brain tissue volumes. Longitudinal brain growth was assessed from preterm infants' serial scans.
  
  
  RESULTS
  At 42 weeks' postmenstrual age, gray matter volumes were not different between preterm and term infants. Myelinated white matter was decreased, as were unmyelinated white matter volumes in the region including the central gyri. The gray matter proportion of the brain parenchyma constituted 30% and 37% at 32 and 42 weeks' postmenstrual age, respectively.
  
  
  CONCLUSIONS
  This MRI study of preterm infants appropriate for gestational age and without brain injury establishes the influence of early birth on brain development. No decreased cortical gray matter volumes were found, which is in contrast to findings in preterm infants with brain injury. Moderately decreased white matter volumes suggest an adverse influence of early birth on white matter development. We identified a sharp increase in cortical gray matter volume in preterm infants' serial data, which may correspond to a critical period for cortical development.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, Massachusetts 02115, USA. mewes@bwh.harvard.edu
authors.forename: Andrea U J
authors.initials: AU
authors.lastname: Mewes
authors.forename: Petra S
authors.initials: PS
authors.lastname: Hüppi
authors.forename: Heidelise
authors.initials: H
authors.lastname: Als
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Rybicki
authors.forename: Terrie E
authors.initials: TE
authors.lastname: Inder
authors.forename: Gloria B
authors.initials: GB
authors.lastname: McAnulty
authors.forename: Robert V
authors.initials: RV
authors.lastname: Mulkern
authors.forename: Richard L
authors.initials: RL
authors.lastname: Robertson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rivkin
authors.forename: Simon K
authors.initials: SK
authors.lastname: Warfield
mesh_terms: D001921:Brain / Q000254:growth & development* / Q000473:pathology*; D002531:Cerebellum / Q000473:pathology; D002540:Cerebral Cortex / Q000473:pathology; D005865:Gestational Age; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007231:Infant, Newborn; D007234:Infant, Premature; D008279:Magnetic Resonance Imaging