Color Doppler Ultrasonography in the Differentiation of Benign and Malignant Ovarian Tumors

Objective To determine the accuracy of color Doppler ultrasonography in the detection of ovarian malignancy on the basis of resistance index. Design Cross-sectional study. Setting Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University. Subjects 120 patients who had their ovarian tumors removed surgically between June 2000 and September 2001. Method All patients had color Doppler sonography performed prior to surgery. The Doppler results were compared to the histological diagnosis of the ovarian tumors. Main outcome measurement Sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, false negative rate, and accuracy of the preoperative resistance index. Results Of the 113 patients whose intratumoral blood flow could be evaluated, the resistance index was significantly lower in malignant lesions than in benign lesions (0.49+0.14 vs 0.72+0.12, p < 0.001). The sensitivity, specificity, and accuracy of the preoperative resistance index (< 0.5) in detecting malignant ovarian tumors were 71.4%, 93.6%, and 86.7%, respectively; with 83.3% positive predictive value, 88.0% negative predictive value, 6.4% false positive rate, and 28.6% false negative rate. Conclusion Malignant ovarian lesions tended to have low-impedance flow and benign lesions had high-impedance flow. However, some overlap in individual values of resistance index for benign and malignant lesions was found, indicating that color Doppler sonography has limitations in the differentiation of benign from malignant ovarian masses.