title: Comparison of nuchal translucency measurements obtained using Volume NT(TM)  and two- and three-dimensional ultrasound.
abstract: OBJECTIVE
  To evaluate the feasibility of Volume NT(TM) , a new technique that automatically archives mid-sagittal plane views and measures the maximum nuchal translucency (NT) thickness, by comparing its measurements with those made with conventional two- (2D) and three-dimensional (3D) techniques.
  
  
  METHODS
  This was a prospective study of 130 singleton pregnancies undergoing NT screening at 11 + 0 to 13 + 6 weeks of gestation. Fetuses with enlarged NT or multiple anomalies and those in the prone position were excluded. Success rate of NT measurement was assessed using Volume NT(TM) , 2D and 3D techniques. In cases in which all three techniques were successful, intra- and interobserver bias and levels of agreement for NT measurements within and between techniques were evaluated using Bland-Altman plots.
  
  
  RESULTS
  Of 130 cases enrolled into the study, 16 were excluded from analysis due to enlarged NT (n = 3), prone position (n = 2) or missing data (n = 11). Among the 114 cases analyzed, NT measurement was successful by the conventional 2D method in 95.6% (109/114) of cases and by 3D and Volume NT(TM) measurements in 103 and 93 cases, respectively. Success rate was not significantly different between methods. In 89 cases, NT values were available using all three methods. Among them, mean ± SD 2D-NT was 1.3 ± 0.4 mm, 3D-NT was 1.2 ± 0.4 mm and Volume NT(TM) was 1.3 ± 0.4 mm. The mean differences of the intra- and interobserver variability of each method were not significantly different from zero for each method.
  
  
  CONCLUSIONS
  Volume NT(TM) , a novel technique for automated NT measurement, is apparently reproducible and comparable with conventional 2D and 3D ultrasound techniques for NT measurement.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Yonsei University College of Medicine Yonsei University Health System, Seoul, Korea.
authors.forename: H Y
authors.initials: HY
authors.lastname: Cho
authors.forename: J-Y
authors.initials: JY
authors.lastname: Kwon
authors.forename: Y H
authors.initials: YH
authors.lastname: Kim
authors.forename: K H
authors.initials: KH
authors.lastname: Lee
authors.forename: J
authors.initials: J
authors.lastname: Kim
authors.forename: S Y
authors.initials: SY
authors.lastname: Kim
authors.forename: Y W
authors.initials: YW
authors.lastname: Park
mesh_terms: D000328:Adult; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D048208:Nuchal Translucency Measurement / Q000379:methods*; D015588:Observer Variation; D011247:Pregnancy; D011446:Prospective Studies; D015203:Reproducibility of Results; D016216:Ultrasonography, Prenatal / Q000379:methods