Vasa previa: prenatal detection by three‐dimensional ultrasonography

Objective To describe three‐dimensional (3D) ultrasonography (US) for the antepartum diagnosis of vasa previa. Design 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. Conclusion 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. Copyright © 2000 International Society of Ultrasound in Obstetrics and Gynecology