title: The intradecidual sign: is it reliable for diagnosis of early intrauterine pregnancy?
abstract: OBJECTIVE
  Our aim was to determine the accuracy of the intradecidual sign for the diagnosis of intrauterine pregnancy and the exclusion of ectopic pregnancy.
  
  
  CONCLUSIONS
  The intradecidual sign reliably excludes the presence of an ectopic pregnancy. The sensitivity for diagnosis of an intrauterine pregnancy increases when human chorionic gonadotropin levels are equal to or greater than 2,000 mIU/mL or the mean sac diameter is equal to or greater than 3 mm. It is of utmost importance to visualize this sign on multiple views with an unchanging appearance.
authors.affiliation: Harvard Medical School, 25 Shattuck St., Boston, MA 02115, USA.
authors.forename: Gloria
authors.initials: G
authors.lastname: Chiang
authors.forename: Deborah
authors.initials: D
authors.lastname: Levine
authors.forename: Michelle
authors.initials: M
authors.lastname: Swire
authors.forename: Ann
authors.initials: A
authors.lastname: McNamara
authors.forename: Tejas
authors.initials: T
authors.lastname: Mehta
mesh_terms: D000328:Adult; D003656:Decidua / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal