title: Nasal bone length: prenasal thickness ratio: a strong 2D ultrasound marker for Down syndrome.
abstract: OBJECTIVE
  To evaluate the feasibility of incorporating two-dimensional ultrasound measurements of nasal bone length (NBL) and prenasal thickness (PT) into the second-trimester anomaly scan and to determine whether the NBL : PT ratio could help in differentiating euploid and Down syndrome fetuses.
  
  
  METHODS
  Two-dimensional measurements of NBL and PT were obtained from the midsagittal plane of the fetal head at 14-28 weeks of gestation in a Caucasian population at risk for aneuploidy. The screening performances of NBL, PT, and the ratios NBL : PT and PT : NBL were analyzed in euploid (n = 1330) and Down syndrome (n = 33) fetuses.
  
  
  RESULTS
  Nasal bone length and PT alone showed strong correlations with Down syndrome (sensitivity: 76% at 1.88% and 2.35% false positive rate, respectively). However, the NBL : PT ratio showed an even stronger correlation with Down syndrome (false positive rate: 0.9%, sensitivity: 97%). The mean NBL : PT ratio showed a gradual increase from 1.48 to 1.79 (a 21.2% increase) between 14 and 28 weeks of gestation.
  
  
  CONCLUSIONS
  Two-dimensional ultrasound measurements of NBL and PT, particularly the NBL : PT ratio, are highly sensitive markers for Down syndrome fetuses.
authors: MEDISONO Fetal and Adult Health Research Center, Szeged, Hungary; Department of Medical Genetics, University of Szeged, Szeged, Hungary.
authors: Andrea
authors: A
authors: Szabó
authors: Károly
authors: K
authors: Szili
authors: János Tamás
authors: JT
authors: Szabó
authors: János
authors: J
authors: Sikovanyecz
authors: Dóra
authors: D
authors: Isaszegi
authors: Emese
authors: E
authors: Horváth
authors: János
authors: J
authors: Szabó
mesh_terms: D000328:Adult; D015415:Biomarkers; D004314:Down Syndrome / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D009295:Nasal Bone / Q000000981:diagnostic imaging*; D011247:Pregnancy; D012016:Reference Values; D016216:Ultrasonography, Prenatal; D055815:Young Adult
chemical_list: D015415:Biomarkers