title: Fractional moving blood volume estimation in the fetal lung using power Doppler ultrasound: a reproducibility study.
abstract: OBJECTIVE
  To evaluate the reproducibility of fractional moving blood volume (FMBV) estimation in the fetal lung using power Doppler ultrasound (PDU).
  
  
  METHODS
  The lung blood perfusion of 20 normally grown singleton fetuses at 32-35 weeks of gestation was evaluated by two experienced observers using PDU. Each observer recorded two consecutive sequences of images from the posterior part of the fetal lung and calculated FMBV offline. FMBV expresses the percentage of blood movement within a defined region of interest (ROI). Repeatability and agreement were evaluated by means of the intraclass (intraCC) and interclass (interCC) correlation coefficients.
  
  
  RESULTS
  FMBV was successfully evaluated in 17/20 fetuses by both observers (kappa index 0.82; 95% CI 0.51-0.93). The intraCC for repeatability for Observer A was 0.92 (95% CI 0.78-0.96), and for Observer B 0.90 (95% CI 0.74-0.96). The mean difference between the first and the second measurement was 0.7% (SD 4.5%). The interCC for repeatability over time and between the operators was 0.70 (95% CI 0.56-0.76) and the mean difference between the observers was 0.6% (SD 4.65%). The interCC for agreement was 0.92 (95% CI 0.84-0.95) and the mean difference in FMBV results when both observers analyzed the same sequences offline was 0.6% (SD 3.85%).
  
  
  CONCLUSIONS
  In the hands of experienced operators, using a well-defined ROI and standard settings, FMBV estimation is a reproducible method of quantifying power Doppler signals recorded from fetal lung blood perfusion.
authors.affiliation: Department of Obstetrics and Gynecology, University of Lund, Lund, Sweden. Edgar.Hernandez-Andrade@gyn.lu.se
authors.forename: E
authors.initials: E
authors.lastname: Hernandez-Andrade
authors.forename: A
authors.initials: A
authors.lastname: Thuring-Jönsson
authors.forename: T
authors.initials: T
authors.lastname: Jansson
authors.forename: G
authors.initials: G
authors.lastname: Lingman
authors.forename: K
authors.initials: K
authors.lastname: Marsál
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D001810:Blood Volume / Q000502:physiology*; D005260:Female; D005318:Fetal Heart / Q000000981:diagnostic imaging; D006351:Heart Valves / Q000000981:diagnostic imaging; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D008168:Lung / Q000098:blood supply* / Q000000981:diagnostic imaging; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D015203:Reproducibility of Results; D018608:Ultrasonography, Doppler / Q000379:methods; D016216:Ultrasonography, Prenatal / Q000379:methods*