title: Cumulative sum plots and retrospective parameters in first-trimester ductus venosus quality assurance.
abstract: OBJECTIVE
  This study aimed to evaluate the application of two quality assurance methods to the ductus venosus pulsatility index (DVPI), as a first-trimester aneuploidy marker, including retrospective assessment of distribution parameters and cumulative sum (CUSUM) plots.
  
  
  METHODS
  The DVPI was measured in 14 444 singleton fetuses at 11+0 to 13+6 weeks in two Fetal Medicine centers during a 4-year period. Sonologist-specific quality assurance distribution parameters, previously described for nuchal translucency, were assessed: the median multiples of the median (MoM), the logarithmic standard deviation of DVPI MoMs and the weekly DVPI percent decrease. Quality assurance results were compared between median MoMs and MoM-based CUSUM plots.
  
  
  RESULTS
  When sonologist-specific DVPI distribution parameters were retrospectively applied for quality assurance, a 1.0 median MoM, a 0.1 median logarithmic standard deviation and a 3.4 median weekly DVPI drop percentage were observed. CUSUM plots showed good agreement with 0.9-1.1 MoMs range for median MoM, in the assessment of sonologist-specific performances.
  
  
  CONCLUSIONS
  Retrospective and prospective DVPI quality assurance methods appear to be applicable to DVPI at 11+0 to 13+6 weeks. Its use should be encouraged if DVPI is to be added to first-trimester Down syndrome or cardiac defects screening.
authors.affiliation: Ultrasound Unit, Department of Obstetrics and Gynecology, Hospital Sant Joan de Déu, Barcelona, Catalonia, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Sabria
authors.forename: Carmina
authors.initials: C
authors.lastname: Comas
authors.forename: Carles
authors.initials: C
authors.lastname: Barceló-Vidal
authors.forename: Miriam
authors.initials: M
authors.lastname: Illa
authors.forename: Monica
authors.initials: M
authors.lastname: Echevarria
authors.forename: Maria Dolors
authors.initials: MD
authors.lastname: Gomez-Roig
authors.forename: Antoni
authors.initials: A
authors.lastname: Borrell
mesh_terms: D000782:Aneuploidy; D025063:Chromosome Disorders / Q000000981:diagnostic imaging*; D005260:Female; D005333:Fetus / Q000098:blood supply / Q000502:physiology*; D006801:Humans; D008403:Mass Screening; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011673:Pulsatile Flow; D011785:Quality Assurance, Health Care; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal / Q000592:standards*