title: Alteration of human fetal subplate layer and intermediate zone during normal development on MR and diffusion tensor imaging.
abstract: OBJECTIVE
  The subplate layer and intermediate zone are the precursors for neonatal white matter. The aims of this study were to evaluate 1) T1 and T2 signal intensity, and 2) FA of subplate and intermediate zone in postmortem fetuses and correlate with histology, and 3) T2 signal intensity of subplate and intermediate zone on antenatal MR imaging.
  
  
  METHODS
  Fourteen immersion-fixed normal brains from 18 to 25 gestational weeks underwent 1.5T MR imaging, including DTI and histologic examination. The subplate and intermediate zone were graded on a scale of 1-5 on T1 and T2, and FAs were evaluated and then correlated with age. Seventeen antenatal MR images from 20 to 26 gestational weeks with normal brain were evaluated by using the same grading.
  
  
  RESULTS
  On T1 postmortem MR imaging, subplate has lower signal intensity compared with intermediate zone; subplate signal intensity correlated positively (r = 0.66, P = .012) with age, and intermediate zone signal intensity correlated negatively (r = -0.78, P = .001) with age. On T2 postmortem MR imaging, subplate has higher signal intensity compared with intermediate zone and remained persistently high in signal intensity; intermediate zone signal intensity showed moderate correlation (r = 0.48, P = .086) with age. FA of subplate correlated positively (r = 0.55, P < .001) with age; FA of intermediate zone correlated negatively (r = -0.64, P < .0001) with age. On histology, extracellular matrix decreased and cellularity increased in subplate layer, tangentially organized cellularity decreased, and projecting fibers became thicker in intermediate zone with increasing gestation. The findings on T2-weighted antenatal MR imaging were similar to T2-weighted postmortem MR imaging.
  
  
  CONCLUSIONS
  The changes in signal intensity and FA of subplate and intermediate zone in the second trimester reflect microstructural changes on histology.
authors.affiliation: Diagnostic Imaging, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada. Elysa.Widjaja@sickkids.ca
authors.forename: E
authors.initials: E
authors.lastname: Widjaja
authors.forename: S
authors.initials: S
authors.lastname: Geibprasert
authors.forename: S Z
authors.initials: SZ
authors.lastname: Mahmoodabadi
authors.forename: S
authors.initials: S
authors.lastname: Blaser
authors.forename: N E
authors.initials: NE
authors.lastname: Brown
authors.forename: P
authors.initials: P
authors.lastname: Shannon
mesh_terms: D016880:Anisotropy; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000166:cytology* / Q000196:embryology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005865:Gestational Age; D006801:Humans; D008279:Magnetic Resonance Imaging; D009413:Nerve Fibers, Myelinated; D009434:Neural Pathways / Q000166:cytology* / Q000196:embryology*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012016:Reference Values; D012189:Retrospective Studies