title: Are there any differences in three-dimensional placental vascular indices obtained using conventional power Doppler and high-definition flow imaging?
abstract: OBJECTIVE
  The purpose of this study was to determine whether there are differences in values and reproducibility of three-dimensional (3D) vascular indices obtained on placental volumes using power Doppler (PD) or high-definition flow imaging (HDFI) techniques.
  
  
  METHODS
  A prospective study was performed on 121 uncomplicated singleton pregnancies at 11 + 0 to 13 + 6 weeks of gestation. Two placental volumes were acquired from each pregnancy. Vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were then analyzed and compared. In order to assess the reproducibility of the measurements, two additional placental volumes obtained with both PD and HDFI were acquired in 31 pregnancies and the agreement assessed by intraclass correlation coefficients. Inter-observer variability was assessed by analyzing all the volumes by two observers blinded to each other's.
  
  
  RESULTS
  A significant relationship was observed between the vascular indices values obtained with the two techniques (VI Pearson's r=0.891 p<0.001; FI r=0.769 p<0.001; VFI r=0.847 p<0.001). The median values of VI, FI and VFI were significantly higher when obtained with HDFI imaging. In serial recordings, the ICCs resulted higher when volumes were acquired with HDFI rather than with PD techniques. Similarly, HDFI demonstrated a higher inter-observer reproducibility.
  
  
  CONCLUSIONS
  3D vascular indices calculated using HDFI are higher than those calculated using conventional PD. Although the relationship between the two methods is high, HDFI shows a better reproducibility suggesting its potential clinical application.
authors.affiliation: Fetal Medicine Center Genoma, Università di Roma “Tor Vergata”, Rome, Italy. giuseppe.rizzo@uniroma2.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Rizzo
authors.forename: Maria Elena
authors.initials: ME
authors.lastname: Pietrolucci
authors.forename: Eloisa
authors.initials: E
authors.lastname: Aiello
authors.forename: Estelle
authors.initials: E
authors.lastname: Dijmeli
authors.forename: Costanza
authors.initials: C
authors.lastname: Bosi
authors.forename: Domenico
authors.initials: D
authors.lastname: Arduini
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D005260:Female; D005865:Gestational Age; D006305:Health Status Indicators; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D015588:Observer Variation; D009929:Organ Size; D010298:Parity; D010920:Placenta / Q000033:anatomy & histology / Q000098:blood supply* / Q000000981:diagnostic imaging*; D011247:Pregnancy; D018616:Ultrasonography, Doppler, Duplex; D016216:Ultrasonography, Prenatal / Q000379:methods*