title: Maturation of the limbic system revealed by MR FLAIR imaging.
abstract: BACKGROUND
  Cortical signal intensity (SI) of the limbic system in adults is known to be higher than in neocortical structures, but time-related changes in SI during childhood have not been described.
  
  
  OBJECTIVE
  To detect maturation-related SI changes within the limbic system using a fluid-attenuated inversion recovery (FLAIR) MR sequence.
  
  
  METHODS
  Twenty children (10 boys, 10 girls; age 3.5-18 years, mean 11.2 years) with no neurological abnormality and normal MR imaging examination were retrospectively selected. On two coronal FLAIR slices, ten regions of interest (ROI) with a constant area of 10 mm2 were manually placed in the archeocortex (hippocampus), periarcheocortex (parahippocampal gyrus, subcallosal area, cingulate gyrus) and in the neocortex at the level of the superior frontal gyrus on both sides.
  
  
  RESULTS
  Significant SI gradients were observed with a higher intensity in the archeocortex, intermediate intensity in the periarcheocortex and low intensity in the neocortex. Significant higher SI values in hippocampal and parahippocampal structures were detected in children up to 10 years of age.
  
  
  CONCLUSIONS
  These differences mainly reflected differences in cortical structure and myelination state. Archeocortical structures especially showed significant age-related intensity progression suggesting ongoing organization and/or myelination until early adolescence.
authors.affiliation: Department of Paediatric Radiology, University Children's Hospital UKBB, Römergasse 8, Basel, 4058, Switzerland. jacques.schneider@ukbb.ch
authors.forename: Jacques Frédéric
authors.initials: JF
authors.lastname: Schneider
authors.forename: Klara
authors.initials: K
authors.lastname: Vergesslich
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003337:Corpus Callosum / Q000033:anatomy & histology / Q000254:growth & development; D005260:Female; D006179:Gyrus Cinguli / Q000033:anatomy & histology / Q000254:growth & development; D006624:Hippocampus / Q000033:anatomy & histology / Q000254:growth & development; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008032:Limbic System / Q000033:anatomy & histology / Q000254:growth & development*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009186:Myelin Sheath / Q000502:physiology; D019579:Neocortex / Q000033:anatomy & histology / Q000254:growth & development; D020534:Parahippocampal Gyrus / Q000033:anatomy & histology / Q000254:growth & development; D012189:Retrospective Studies