Chorionic rim sign on transvaginal sonography: Unrealiable of intrauterine pregnancy
Magnetic Resonance Imaging
The purpose of this study was to assess the value of the chorionic rim sign as evidence of intrauterine pregnancy on transvaginal sonography. The chorionic rim sign (a curvilinear echogenic rim separate from the underlying decidua that borders an outwardly convex intrauterine fluid collection) has been reported to be helpful in differentiating between a true gestational sac and a pseudosac when transvaginal sonography in a pregnant patient with symptoms shows a nondescript intrauterine fluid collection. We retrospectively reviewed transvaginal sonograms performed in 88 consecutive patients with symptoms in whom the final diagnosis was ectopic pregnancy. An intrauterine fluid collection (i.e., pseudosac) was identified in 12 patients. The chorionic rim sign was identified in one third of the patients with a pseudosac. When an otherwise nondescript intrauterine fluid collection is seen in a pregnant patient with symptoms, the presence of the chorionic rim sign does not reliably exclude the possibility of a pseudosac related to ectopic pregnancy.