title: Reproducibility of 3-dimensional sonographic measurements of fetal and placental volume at gestational ages of 11-18 weeks.
abstract: OBJECTIVE
  Determine the reproducibility of 3D ultrasound (3DUS) measurements of fetal and placental volumes.
  
  
  METHODS
  We included 34 pregnant women between gestational weeks (GW) 11-18. Two operators independently acquired fetal and placental volumes using 3DUS. Each volume was acquired twice and stored on disk for off-line analysis. Intra- and interobserver reproducibility was expressed in the intra- and interclass correlation coefficient (intra-CC and inter-CC). In addition, the 3DUS volumes acquired by the first operator were calculated by the second and vice-versa to evaluate the effect of volume acquisition and caliper placement. A value >0.75 was considered a good agreement.
  
  
  RESULTS
  Fetal and placental volume measurements were successful in 97% of all cases. Between GW 11-14 and 14-18 the median fetal volume was 20.8 (5.0-35.1) and 51.7 (37.9-132.8) ml, the median placental volume was 71.3 (40.9-111.9) and 120.7 (94.2- 273.7) ml. Bland-Altman plots were used for statistical analysis. The intraobserver reproducibility was good for fetus (intra-CC: 0.99; 0.99) and placenta (intra-CC: 0.99; 0.98). Also, interobserver reproducibility was good for fetus (inter-CC 0.98) and placenta (inter-CC 0.98). In addition, regardless of the operator who acquired the volumes, the inter-CC remained good for both fetus (inter-CC: 0.99; 0.99) and placenta (inter-CC: 0.97; 0.99).
  
  
  CONCLUSIONS
  The reproducibility of fetal and placental volume measurements by 3DUS between GW 11-18 is good. In addition, individually chosen caliper placement and volume acquisition has no effect on the calculation of either volumes.
authors.affiliation: Department of Obstetrics and Gynecology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Koen
authors.initials: K
authors.lastname: Deurloo
authors.forename: Marieke
authors.initials: M
authors.lastname: Spreeuwenberg
authors.forename: Marijke
authors.initials: M
authors.lastname: Rekoert-Hollander
authors.forename: John
authors.initials: J
authors.lastname: van Vugt
mesh_terms: D000328:Adult; D001185:Artificial Intelligence; D005260:Female; D005865:Gestational Age; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009426:Netherlands; D015588:Observer Variation; D010920:Placenta / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011446:Prospective Studies; D015203:Reproducibility of Results; D016216:Ultrasonography, Prenatal