title: A novel method for evaluating uterine cervical consistency using vaginal ultrasound gray-level histogram.
abstract: To evaluate uterine cervical consistency using a vaginal ultrasound gray-level histogram.
  
  
  
  Vaginal ultrasound and digital examination were performed for 214 women with low-risk singleton pregnancy during 27-30(th) pregnancy week. The mean gray-level (MGL) of an ultrasound gray-level histogram, representing the echogenicity of a region of interest, was measured in the midsection of anterior and posterior cervical walls. The difference in MGL between anterior and posterior (AP difference) was related to the Bishop sub-score for cervical consistency (0, 1, or 2), determined before ultrasound.
  
  
  
  A larger positive AP difference indicated significantly lower Bishop sub-score. After analyzing the receiver operator characteristic curves for the AP difference, a value of 1.42 and -1.98 was the best cut-off value to determine a hard cervix (score 0) and a soft cervix (score 2), respectively. To identify a hard cervix, this test had 71% sensitivity and 82% specificity. For a soft cervix, it was 66% and 87%, respectively.
  
  
  
  A more echogenic anterior than posterior cervix indicates a hard cervix; the greater the difference in echogenicity between anterior and posterior walls the harder the cervix. The difference in MGL of the ultrasound gray-level histogram may enable objective evaluation of cervical consistency.
authors.affiliation: Department of Obstetrics and Gynecology, Jichi Medical University, Shimotsuke, Tochigi, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kuwata
authors.forename: Shigeki
authors.initials: S
authors.lastname: Matsubara
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Taniguchi
authors.forename: Akihide
authors.initials: A
authors.lastname: Ohkuchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohkusa
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D000328:Adult; D020070:Cervical Ripening; D002584:Cervix Uteri / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D016216:Ultrasonography, Prenatal / Q000379:methods* / Q000706:statistics & numerical data; D014621:Vagina / Q000000981:diagnostic imaging*