Predictive Value of Single or Combined Ultrasound Signs in the Diagnosis of Ovarian Torsion.

Objectives: To determine predictive values of isolated and combined ultrasound signs in the diagnosis of adnexal torsion.

Methods: This work was a retrospective study of 129 adult female patients who underwent an ultrasound examination followed by a definitive surgical procedure within a 24-hour period to determine whether adnexal torsion was present.

Results: The positive predictive value (PPV) of the ultrasound diagnosis of adnexal torsion was 82.2%. The statistically significant ultrasound signs in multivariate logistic regression with single-predictor analyses were relative enlargement of the ovary, an abnormal adnexal position, a twisted vascular pedicle, and the follicular edema "ring sign." Possible combinations of these ultrasound criteria showed high specificities (74%-100%), high PPVs (93%-100%), and lower sensitivities (29%-71%) and negative predictive values (24%-35%). Any combination that included a twisted vascular pedicle or the follicular ring sign as one of the signs had high odds ratios and positive likelihood ratios.

Conclusions: Ultrasound has a high PPV as a first-choice imaging modality in the diagnosis of adnexal torsion. The combinations of the following 4 statistically significant ultrasound signs, consisting of an abnormal position, relative enlargement of the index ovary, a twisted vascular pedicle, and the follicular edema ring sign, substantially narrow the imaging differential diagnosis in such cases. The presence of vascular pedicle twisting and the follicular ring sign was highly associated with a positive ovarian torsion diagnosis, with 100% specificity.