title: Mid-facial anthropometry in second-trimester fetuses with trisomy 21: a three-dimensional ultrasound study.
abstract: OBJECTIVE
  The aim of this study was to evaluate whether fetuses with trisomy 21 and detectable nasal bones have a distinct facial anthropometry that can be objectively defined using three-dimensional (3D) ultrasonography.
  
  
  METHODS
  A prospective cross-sectional study of 40 fetuses in the second trimester, 17 with trisomy 21 and 23 controls, was performed. The 3D volume datasets of each case were evaluated for documentation of the nasal bones using the multiplanar and the maximum mode. The nasal bone length and the angle formed by the two maxillary bones at the level of the frontal process were then measured.
  
  
  RESULTS
  The nasal bones were absent in 7 (41%) of the 17 fetuses with Down syndrome. All of the 23 normal fetuses had detectable nasal bones. The difference between nasal bone length in trisomy 21 fetuses and controls did not reach statistical significance (p = 0.087). The mean maxillary angle in trisomy 21 fetuses with nasal bones was significantly wider compared to controls (p = 0.029).
  
  
  CONCLUSIONS
  The nasal bones are present in the majority of fetuses with trisomy 21 in the second trimester. This group of fetuses has a characteristic mid-facial anthropometry (wider maxillary angle) that can be assessed by means of 3D ultrasonography.
authors.affiliation: Department of Obstetrics and Gynecology of the Charité University Hospital-Campus Mitte, Berlin, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Bergann
authors.forename: Christian
authors.initials: C
authors.lastname: Bamberg
authors.forename: Katja
authors.initials: K
authors.lastname: Eder
authors.forename: Hans
authors.initials: H
authors.lastname: Proquitté
authors.forename: John P
authors.initials: JP
authors.lastname: Hartung
authors.forename: Rainer
authors.initials: R
authors.lastname: Bollmann
authors.forename: Karim D
authors.initials: KD
authors.lastname: Kalache
mesh_terms: D000328:Adult; D000886:Anthropometry / Q000379:methods*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004314:Down Syndrome / Q000000981:diagnostic imaging* / Q000196:embryology* / Q000473:pathology; D005260:Female; D005865:Gestational Age; D006801:Humans; D021621:Imaging, Three-Dimensional; D007621:Karyotyping; D008437:Maxilla / Q000000981:diagnostic imaging; D009295:Nasal Bone / Q000000981:diagnostic imaging / Q000196:embryology*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal