Tubal ring sign, also referred to as bagel sign or blob sign, one of the ultrasound signs of a tubal ectopic. It comprises of an echogenic ring which surrounds an unruptured ectopic pregnancy. It is said to have a 95% positive predictive value (PPV) for ectopic pregnancy.
It can be mimicked by a normal corpus luteum. To differentiate the two, bimanual exam can be useful to differentiate an ovarian corpus luteum (moves with ovary) from a tubal ectopic (moves separately from the ovary). Normal ovarian tissue may also be noticeable around a corpus luteum.
- 1. Weissleder R, Wittenberg J, Harisinghani MM et-al. Primer of Diagnostic Imaging, Expert Consult- Online and Print. Mosby Inc. (2011) ISBN:0323065384. Read it at Google Books - Find it at Amazon
- 2. Chudleigh P, Thilaganathan B. Obstetric ultrasound, how, why and when. Churchill Livingstone. (2004) ISBN:0443054711. Read it at Google Books - Find it at Amazon
- 3. Condous, G., Okaro, E. & Bourne, T. Gynecol Surg (2004) 1: 81. https://doi.org/10.1007/s10397-004-0013-4