title: A standardized measurement technique may improve the reliability of measurements of endometrial thickness and volume.
abstract: OBJECTIVE
  To investigate whether standardization of the multiplanar view (SMV) when evaluating the uterus using three-dimensional ultrasonography (3D-US) improves intra- and interobserver reliability and agreement with regard to endometrial measurement.
  
  
  METHODS
  Two-dimensional (2D) and 3D-US was used to measure endometrial thickness by two observers in 30 women undergoing assisted reproduction treatment. Endometrial volume was measured with Virtual Organ Computer-aided AnaLysis (VOCAL(™)) in the longitudinal (A) and coronal (C) planes using an unmodified multiplanar view (UMV) and a standardized multiplanar view (SMV). Measurement reliability was evaluated by intraclass correlation coefficient (ICC) and agreement was examined using Bland-Altman plots with limits of agreement (LoA). The ease of outlining the endometrial-myometrial interface was compared between the A- and C-planes using subjective assessment.
  
  
  RESULTS
  Endometrial volume measurements using the SMV and A-plane were more reliable (intra- and interobserver ICCs, 0.979 and 0.975, respectively) than were measurements of endometrial thickness using 2D-US (intra- and interobserver ICCs, 0.742 and 0.702, respectively) or 3D-US (intra- and interobserver ICCs, 0.890 and 0.784, respectively). The LoAs were narrower for SMV than for UMV. Reliability and agreement were not much different between the A- and C-planes. However the observers agreed that delineating the endometrial-myometrial interface using the A-plane was easier (first and second observer, 50.0 and 46.7%, respectively) or 'comparable' (50 and 53.3%, respectively), but never more difficult than using the C-plane.
  
  
  CONCLUSIONS
  Endometrial volume measurements are more reliable than endometrial thickness measurements and are best performed using SMV and the A-plane.
authors.affiliation: Departamento de Ginecologia e Obstetrícia da Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (FMRP-USP), Ribeirão Preto, Brazil. wpmartins@gmail.com
authors.forename: W P
authors.initials: WP
authors.lastname: Martins
authors.forename: N J
authors.initials: NJ
authors.lastname: Raine-Fenning
authors.forename: S P
authors.initials: SP
authors.lastname: Leite
authors.forename: R A
authors.initials: RA
authors.lastname: Ferriani
authors.forename: C O
authors.initials: CO
authors.lastname: Nastri
mesh_terms: D000328:Adult; D004717:Endometrium / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000145:classification / Q000379:methods*; D015588:Observer Variation; D015203:Reproducibility of Results; D027724:Reproductive Techniques, Assisted; D014463:Ultrasonography; D055815:Young Adult