title: Interobserver variability of midtrimester fetal nuchal thickness.
abstract: OBJECTIVE
  To assess the interobserver variability of ultrasound measured fetal nuchal thickness (NT).
  
  
  METHODS
  NT was measured in 103 consecutive early midtrimester pregnancies (13-18 weeks) by three ultrasonographists with different levels of expertise, in our Prenatal Unit. Measurements were obtained prior to amniocentesis, blindly in relation to other examiners' values. The Lin's concordance correlation coefficient and the Kappa statistics were used to assess concordance between observed values.
  
  
  RESULTS
  Mean differences between pairs of observers ranged from 0.44 to 0.57 mm. A higher concordance correlation between measurements was obtained between the more experienced observers (r = 0.77 versus r = 0.51). When assigning cases with a NT > or = 5 mm to a group at risk for Down's syndrome, a high concordance between experienced ultrasonographists was observed (98% agreement; kappa = 0.90).
  
  
  CONCLUSIONS
  Interobserver variability in NT was acceptable between experienced ultrasonographists.
authors.affiliation: Department of Obstetrics and Gynecology, University of Barcelona Medical School, Catalonia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Borrell
authors.forename: D
authors.initials: D
authors.lastname: Costa
authors.forename: R D
authors.initials: RD
authors.lastname: Delgado
authors.forename: J M
authors.initials: JM
authors.lastname: Martinez
authors.forename: C
authors.initials: C
authors.lastname: Borrell
authors.forename: A
authors.initials: A
authors.lastname: Fortuny
mesh_terms: D000328:Adult; D004314:Down Syndrome / Q000000981:diagnostic imaging; D005260:Female; D005865:Gestational Age; D006801:Humans; D008423:Maternal Age; D009333:Neck / Q000000981:diagnostic imaging* / Q000196:embryology*; D015588:Observer Variation; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D016216:Ultrasonography, Prenatal