Diagnosis of polycystic ovaries by three-dimensional transvaginal ultrasound

Objective: To study diagnostic thresholds for polycystic ovary (PCO). Design: Retrospective cohort study. Setting: Academic hospital. Patient(s): Normoandrogenic ovulatory women and patients with polycystic ovary syndrome (PCOS). Intervention(s): Two-dimensional (2D) and three-dimensional (3D) transvaginal ultrasound. Main Outcome Measure(S): The mean follicle number per ovary (FNPO) of both ovaries and the maximum number follicles in a single sonographic plane (FSSP) of either ovary were determined using 3D transvaginal ultrasound. Ovarian volume was determined using 2D transvaginal ultrasound. Result(s): Twenty-nine normoandrogenic ovulatory women were compared with 10 patients with PCOS. Diagnostic thresholds for PCO with 100% specificity as determined by receiver operator characteristic (ROC) curves were >= 20 for mean FNPO, >= 10 for maximum FSSP, and >= 13 cm(3) for ovarian volume. Both 2D and 3D transvaginal ultrasound were highly accurate in the diagnosis of PCO as determined by areas under the curve (AUC) that were >90% for all three measures. Conclusion(s): Mean FNPO and maximum FSSP by 3D transvaginal ultrasound have comparable high accuracy for diagnosis of PCO. The diagnostic threshold with 100% specificity for mean FNPO is 20, which is greater than suggested by the Rotterdam Consensus Workshop in 2003. Use of the consensus standard, consequently, may result in overdiagnosis of PCO. A threshold of >= 20 mean FNPO using 3D transvaginal ultrasound may be appropriate to minimize false-positive diagnoses of PCO.