title: Screening performance of different methods defining fetal nasal bone hypoplasia as a single and combined marker for the detection of trisomy 21 in the second trimester.
abstract: OBJECTIVE
  To evaluate different methods of defining fetal nasal bone hypoplasia in the second trimester for the detection of trisomy 21.
  
  
  METHODS
  Prospective study in Greek women undergoing anomaly scan between 18 + 0 and 23 + 6 weeks. The following methods of defining nasal bone hypoplasia were evaluated, either as a single marker or in combination with others: (1) BPD to nasal bone length (NBL) ratio; (2) multiples of the median (MoM) of NBL, according to normal curves from a Greek population; (3-4) NBL < 2.5 percentile according to normal curves (3) commonly used internationally curves and (4) curves from a Greek population.
  
  
  RESULTS
  In total, 1301 singleton fetuses were evaluated - 10 with trisomy 21. The best detection rate of trisomy 21 was achieved when the applied method was nasal bone percentiles adjusted to maternal ethnicity, in combination with other markers (<2.5 percentile according to normal curves from a Greek population; p < 0.001; sensitivity 50%; specificity 94.8%; false-positive rate 5.2%; positive likelihood ratio 9.6).
  
  
  CONCLUSIONS
  Screening performance of fetal nasal bone hypoplasia in detecting trisomy 21 varies according to the method applied. The best screening performance is achieved by using percentiles adjusted to maternal ethnicity in combination with other markers of aneuploidy.
authors.affiliation: a 1st Department of Obstetrics and Gynecology , Papageorgiou Hospital, Medical School, Aristotle University of Thessaloniki , Thessaloniki , Greece .|b Prenatal Diagnostic Center of Thessaloniki , Thessaloniki , Greece .
authors.forename: Panayiota
authors.initials: P
authors.lastname: Papasozomenou
authors.affiliation: a 1st Department of Obstetrics and Gynecology , Papageorgiou Hospital, Medical School, Aristotle University of Thessaloniki , Thessaloniki , Greece .|b Prenatal Diagnostic Center of Thessaloniki , Thessaloniki , Greece .
authors.forename: Apostolos P
authors.initials: AP
authors.lastname: Athanasiadis
authors.affiliation: a 1st Department of Obstetrics and Gynecology , Papageorgiou Hospital, Medical School, Aristotle University of Thessaloniki , Thessaloniki , Greece .|c Research Laboratory , School of Health and Medical Care, Alexander Technological Institute of Thessaloniki , Thessaloniki , Greece , and.
authors.forename: Menelaos
authors.initials: M
authors.lastname: Zafrakas
authors.affiliation: c Research Laboratory , School of Health and Medical Care, Alexander Technological Institute of Thessaloniki , Thessaloniki , Greece , and.
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Panteris
authors.affiliation: a 1st Department of Obstetrics and Gynecology , Papageorgiou Hospital, Medical School, Aristotle University of Thessaloniki , Thessaloniki , Greece .
authors.forename: Themistokles
authors.initials: T
authors.lastname: Mikos
authors.affiliation: d 2nd Department of Obstetrics and Gynecology , Hippokratio Hospital, Medical School, Aristotle University of Thessaloniki , Thessaloniki , Greece.
authors.forename: Angelos
authors.initials: A
authors.lastname: Daniilidis
authors.affiliation: d 2nd Department of Obstetrics and Gynecology , Hippokratio Hospital, Medical School, Aristotle University of Thessaloniki , Thessaloniki , Greece.
authors.forename: Aristoteles
authors.initials: A
authors.lastname: Loufopoulos
authors.affiliation: d 2nd Department of Obstetrics and Gynecology , Hippokratio Hospital, Medical School, Aristotle University of Thessaloniki , Thessaloniki , Greece.
authors.forename: Efstratios
authors.initials: E
authors.lastname: Assimakopoulos
authors.affiliation: a 1st Department of Obstetrics and Gynecology , Papageorgiou Hospital, Medical School, Aristotle University of Thessaloniki , Thessaloniki , Greece .
authors.forename: Basil C
authors.initials: BC
authors.lastname: Tarlatzis
mesh_terms: D004314:Down Syndrome / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008403:Mass Screening; D009295:Nasal Bone / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal / Q000379:methods*
keywords: Fetal nasal bone hypoplasia; fetal nasal bone length; screening performance; second trimester