title: Vasa previa: prenatal detection by three-dimensional ultrasonography.
abstract: OBJECTIVE
  To describe three-dimensional (3D) ultrasonography (US) for the antepartum diagnosis of vasa previa.
  
  
  METHODS
  This was a descriptive study of two pregnant women who were suspected to have vasa previa by conventional gray-scale ultrasonography. Three-dimensional studies were also performed during the early third trimester to further investigate the possibility of this condition.
  
  
  RESULTS
  In the first case, 3D US provided gray-scale multiplanar and surface-rendered views of an aberrant vessel over the internal cervical os. For the second case, a 'flight-path' technique allowed the examiner to follow axial views of the endocervical canal toward the internal os until an aberrant vessel was verified. The 'niche-mode' analysis, with and without color power Doppler ultrasonography, was also used to confirm the diagnosis.
  
  
  CONCLUSIONS
  Three-dimensional ultrasonography offers several additional imaging tools that are not currently provided by more conventional ultrasonography for the detection of vasa previa. It represents an important adjunct to two-dimensional (2D) studies, especially when this diagnosis is questionable.
authors.affiliation: Division of Fetal Imaging, Department of Obstetrics and Gynecology, William Beaumont Hospital, 3601 West Thirteen Mile Road, Royal Oak, MI 48073-6769, USA.
authors.forename: W
authors.initials: W
authors.lastname: Lee
authors.forename: J S
authors.initials: JS
authors.lastname: Kirk
authors.forename: C H
authors.initials: CH
authors.lastname: Comstock
authors.forename: R
authors.initials: R
authors.lastname: Romero
mesh_terms: D000328:Adult; D005260:Female; D005333:Fetus / Q000098:blood supply*; D006801:Humans; D010920:Placenta / Q000098:blood supply*; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000000981:diagnostic imaging*; D011263:Pregnancy Trimester, Third; D018615:Ultrasonography, Doppler, Color / Q000379:methods*; D016216:Ultrasonography, Prenatal / Q000379:methods*; D014621:Vagina