title: Nasal bone evaluation in fetuses with Down syndrome during the second and third trimesters of pregnancy.
abstract: OBJECTIVE
  This study examined the use of three-dimensional ultrasonography for evaluating the fetal nasal bone, as a sonographic marker of Down syndrome, during the second and early third trimesters of pregnancy.
  
  
  METHODS
  Forty fetuses, including 20 with trisomy 21, were scanned once by three-dimensional ultrasonography. A midline sagittal view of the facial profile was used to analyze the volume data. Independent examiners reviewed blinded and randomly allocated volume data sets for the nasal bone. Interobserver reliability was evaluated for the sonographic presence or absence of the nasal bone. Logistic regression determined the contribution of this parameter to the presence of Down syndrome.
  
  
  RESULTS
  Both examiners showed substantial agreement in scoring whether the nasal bone was visualized by three-dimensional ultrasonography (P < .001). They identified 40% to 45% of fetuses with abnormalities using the absence of the nasal bone as a sonographic marker. However, a substantial number of fetuses with abnormalities were also found to have a nasal bone present. The nasal bone was visualized in 80% to 90% of fetuses without abnormalities.
  
  
  CONCLUSIONS
  Three-dimensional ultrasonography can be used to evaluate the fetal nasal bone with substantial interobserver agreement during the second and early third trimesters of pregnancy. A nonvisualized nasal bone identified 40% to 45% of fetuses with Down syndrome in this study.
authors.affiliation: Division of Fetal Imaging, Department of Obstetrics and Gynecology, William Beaumont Hospital, 3601 W Thirteen Mile Rd, Royal Oak, Ml 48073-6769, USA.
authors.forename: Wesley
authors.initials: W
authors.lastname: Lee
authors.forename: Greggory R
authors.initials: GR
authors.lastname: DeVore
authors.forename: Christine H
authors.initials: CH
authors.lastname: Comstock
authors.forename: Karim D
authors.initials: KD
authors.lastname: Kalache
authors.forename: Beverley
authors.initials: B
authors.lastname: McNie
authors.forename: Tinnakorn
authors.initials: T
authors.lastname: Chaiworapongsa
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Conoscenti
authors.forename: Marjorie C
authors.initials: MC
authors.lastname: Treadwell
authors.forename: Anthony
authors.initials: A
authors.lastname: Johnson
authors.forename: Raywin
authors.initials: R
authors.lastname: Huang
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
mesh_terms: D004314:Down Syndrome / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D016015:Logistic Models; D009295:Nasal Bone / Q000000981:diagnostic imaging* / Q000196:embryology*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D016216:Ultrasonography, Prenatal