title: Structures Showing Negative Correlations of Signal Intensity with Postnatal Age on T1-weighted Imaging of the Brain of Newborns and Infants.
abstract: OBJECTIVE
  Although the neonatal and infantile brain typically shows sequential T1shortening according to gestational age as a result of myelination, several structures do not follow this rule. We evaluated the relationship between the signal intensity of various structures in the neonatal and infantile brain on T1-weighted imaging (T1WI) and either postnatal or gestational age.
  
  
  METHODS
  We examined magnetic resonance images from 120 newborns and infants without any abnormalities in the central nervous system. Written informed consent was obtained from all parents and the institutional review board approved the study. Gestational age at examination ranged from 35 weeks, 3 days to 46 weeks, 6 days, and postnatal age ranged from 7 days to 127 days. Signal intensity on T1WI was evaluated on a scale from Grade 1 (indistinguishable from surrounding structures) to Grade 4 (higher than cortex and close to fat). We evaluated relationships between the T1signal grades of various structures in the neonatal brain and postnatal or gestational age using Spearman's correlation analysis.
  
  
  RESULTS
  Significant positive correlations were identified between T1signal grade and gestational age in the pyramidal tract (P < 0.001). Conversely, significant negative correlations were evident between T1signal grade and postnatal age (P < 0.001), in structures including the stria medullaris thalami, fornix cerebellar vermis, dentate nucleus and anterior pituitary gland.
  
  
  CONCLUSIONS
  Significant negative correlations exist between signal intensity on T1WI and postnatal age in some structures of the neonatal and infantile brain. Some mechanisms other than myelination might play roles in the course of signal appearance.
authors.affiliation: Department of Radiology, Nara Medical University.
authors.forename: Saeka
authors.initials: S
authors.lastname: Hori
authors.affiliation: Department of Radiology, Nagoya University.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Taoka
authors.affiliation: Department of Radiology, Nara Medical University.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ochi
authors.affiliation: Department of Radiology, Nara Medical University.
authors.forename: Toshiteru
authors.initials: T
authors.lastname: Miyasaka
authors.affiliation: Department of Radiology, Nara Medical University.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Sakamoto
authors.affiliation: Department of Radiology, Nara Medical University.
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Takayama
authors.affiliation: Department of Radiology, Nara Medical University.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Wada
authors.affiliation: Department of Radiology, Nara Medical University.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Myochin
authors.affiliation: Department of Pediatrics, Nara Medical University.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Department of Radiology, Nara Medical University.
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Kichikawa
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology*; D002657:Child Development / Q000502:physiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male
keywords: T1-weighted images; brain; development; magnetic resonance imaging; newborn