Computed Tomography Appearance of the "Whirlpool Sign" in Ovarian Torsion

A 28-year-old female presented to the emergency department complaining of right lower abdominal pain. A contrast-enhanced computed tomography (CT) was done, which showed a 15-centimeter right adnexal cyst with adjacent "whirlpool sign" concerning for right ovarian torsion. Transvaginal pelvic ultrasound (US) revealed a hemorrhagic cyst in the right adnexa, with duplex Doppler identifying arterial and venous flow in both ovaries. Laparoscopic surgery confirmed right ovarian torsion with an attached cystic mass, and a right salpingo-oophorectomy was performed given the mass was suspicious for malignancy.

Ultrasound is the test of choice for diagnosis of torsion due to its ability to evaluate anatomy and perfusion. When ovarian pathology is on the patient's right, appendicitis is high in the differential diagnosis, and CT may be obtained first. Here we describe a case where CT first accurately diagnosed ovarian torsion by demonstrating the whirlpool sign, despite an US that showed arterial flow to the ovary. Future studies should determine whether CT alone is sufficient to diagnose or exclude ovarian torsion.