title: Effect of depth on shear-wave elastography estimated in the internal and external cervical os during pregnancy.
abstract: OBJECTIVE
  To investigate the effect of depth on cervical shear-wave elastography.
  
  
  METHODS
  Shear-wave elastography was applied to estimate the velocity of propagation of the acoustic force impulse (shear wave) in the cervix of 154 pregnant women at 11-36 weeks of gestation. Shear-wave speed (SWS) was evaluated in cross-sectional views of the internal and external cervical os in five regions of interest: anterior, posterior, lateral right, lateral left, and endocervix. Distance from the center of the ultrasound (US) transducer to the center of each region of interest was registered.
  
  
  RESULTS
  In all regions, SWS decreased significantly with gestational age (P=0.006). In the internal os, SWS was similar among the anterior, posterior, and lateral regions and lower in the endocervix. In the external os, the endocervix and anterior regions showed similar SWS values, lower than those from the posterior and lateral regions. In the endocervix, these differences remained significant after adjustment for depth, gestational age, and cervical length. SWS estimations in all regions of the internal os were higher than those of the external os, suggesting denser tissue.
  
  
  CONCLUSIONS
  Depth from the US probe to different regions in the cervix did not significantly affect the SWS estimations.
authors.forename: Edgar
authors.initials: E
authors.lastname: Hernandez-Andrade
authors.forename: Alma
authors.initials: A
authors.lastname: Aurioles-Garibay
authors.forename: Maynor
authors.initials: M
authors.lastname: Garcia
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Korzeniewski
authors.forename: Alyse G
authors.initials: AG
authors.lastname: Schwartz
authors.forename: Hyunyoung
authors.initials: H
authors.lastname: Ahn
authors.forename: Alicia
authors.initials: A
authors.lastname: Martinez-Varea
authors.forename: Lami
authors.initials: L
authors.lastname: Yeo
authors.forename: Tinnakorn
authors.initials: T
authors.lastname: Chaiworapongsa
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Hassan
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
mesh_terms: D000328:Adult; D002584:Cervix Uteri / Q000000981:diagnostic imaging* / Q000502:physiology*; D015331:Cohort Studies; D004547:Elastic Tissue / Q000000981:diagnostic imaging / Q000502:physiology; D004548:Elasticity / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal / Q000379:methods*; D055815:Young Adult