title: Development of fetal brain of 20 weeks gestational age: assessment with post-mortem Magnetic Resonance Imaging.
abstract: BACKGROUND
  The 20th week gestational age (GA) is at mid-gestation and corresponds to the age at which the termination of pregnancy in several countries and the first Magnetic Resonance Imaging (MRI) can be performed, and at which the premature babies may survive. However, at present, very little is known about the exact anatomical character at this GA.
  
  
  OBJECTIVE
  To delineate the developing fetal brain of 20 weeks GA and obtain the three dimensional visualization model.
  
  
  METHODS
  20 fetal specimens were scanned by 3.0 T and 7.0 T post-mortem MRI, and the three dimensional visualization model was obtained with Amira 4.1.
  
  
  RESULTS
  Most of the sulci or their anlage, except the postcentral sulcus and intraparietal sulcus, were present. The laminar organization, described as layers with different signal intensities, was most clearly distinguished at the parieto-occipital lobe and peripheral regions of the hippocampus. The basal nuclei could be clearly visualized, and the brain stem and cerebellum had formed their common shape. On the visualization model, the shape and relative relationship of the structures could be appropriately delineated. The ranges of normal values of the brain structures were obtained, but no sexual dimorphisms or cerebral asymmetries were found.
  
  
  CONCLUSIONS
  The developing fetal brain of 20 weeks GA can be clearly delineated on 3.0 T and 7.0 T post-mortem MRIs, and the three dimensional visualization model supplies great help in precise cognition of the immature brain. These results may have positive influences on the evaluation of the fetal brain in the uterus.
authors.affiliation: Research Center for Sectional and Imaging Anatomy, Shandong University School of Medicine, 44 Wen-hua Xi Road, 250012 Jinan, Shandong, China.
authors.forename: Zhonghe
authors.initials: Z
authors.lastname: Zhang
authors.forename: Shuwei
authors.initials: S
authors.lastname: Liu
authors.forename: Xiangtao
authors.initials: X
authors.lastname: Lin
authors.forename: Gaojun
authors.initials: G
authors.lastname: Teng
authors.forename: Taifei
authors.initials: T
authors.lastname: Yu
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
authors.forename: Fengchao
authors.initials: F
authors.lastname: Zang
mesh_terms: D001344:Autopsy; D001921:Brain / Q000033:anatomy & histology / Q000196:embryology* / Q000254:growth & development*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011247:Pregnancy; D011262:Pregnancy Trimester, Second