title: Intraobserver variability of pulsatility index measurements in three fetal vessels in the first trimester.
abstract: OBJECTIVE
  The intraobserver repeatability of pulsatility index measurements in 3 fetal vessels in the early weeks of gestation was evaluated.
  
  
  METHODS
  The pulsatility index was calculated from the flow velocity waveforms from 3 fetal vessels in a series of 58 uneventful, low-risk, singleton first-trimester pregnancies using transvaginal color Doppler sonography. The intraobserver repeatability was expressed as the intraclass correlation coefficient. Mean menstrual age at the time of the examination was 10.3 weeks (range, 7.6-13).
  
  
  RESULTS
  Flow velocity waveforms from the umbilical artery, abdominal aorta, and middle cerebral artery were obtained in 100% (58/58), 98.3% (57/58), and 100% (34/34) of cases, respectively. The intraclass correlation coefficients for these vessels were 0.89, 0.79, and 0.93, respectively.
  
  
  CONCLUSIONS
  The intraobserver repeatability was acceptable for all the vessels studied.
authors.affiliation: Department of Obstetrics and Gynecology, Clínica Universitaria de Navarra, Pamplona, Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: Alcázar
mesh_terms: D000328:Adult; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging* / Q000196:embryology*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging* / Q000196:embryology*; D005260:Female; D005333:Fetus / Q000098:blood supply; D005865:Gestational Age; D006801:Humans; D015588:Observer Variation; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011673:Pulsatile Flow; D018615:Ultrasonography, Doppler, Color; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000000981:diagnostic imaging* / Q000196:embryology*