Sonographic whirlpool sign in ovarian torsion.

OBJECTIVE To describe an additional maneuver during sonography for ovarian torsion and to assess its diagnostic value. METHODS During a period of about 2 years 6 months, 21 patients with acute or intermittent lower abdominal pain who had an ovarian mass and an extraovarian mass suggestive of a twisted vascular pedicle on sonography were studied. The gray scale features of the ovarian mass were recorded. The presence of a twisted vascular pedicle was evaluated. Its location and gray scale features were noted. The probe was moved to and fro along the axis of the pedicle, and the presence of a whirlpool sign was evaluated. The same procedure was repeated on a color Doppler study. RESULTS A twisted pedicle with a whirlpool sign was seen in all 21 patients. Ovarian torsion was confirmed in all 20 patients who underwent surgery. The last patient was pregnant and did well with conservative treatment. Hemorrhagic infarction or early hemorrhage of the ovary or ovarian mass was seen in all 8 patients who did not show flow in the twisted pedicle on the color Doppler study and in 2 patients who showed flow in the artery in the proximal part of the pedicle. Of the 6 patients who showed flow in the artery alone, the ovary was removed in 4, and all had hemorrhagic infarction or early hemorrhage. The ovary was viable in all 5 patients in whom flow was seen in both the artery and vein. CONCLUSIONS A positive whirlpool sign in the twisted vascular pedicle of the ovary is the most definitive sign of ovarian torsion. Absence of blood flow in the twisted pedicle and visualization of the flow in the artery alone are predictive of nonviability of the ovary.