Prospective cross-validation of Doppler ultrasound examination and gray-scale ultrasound imaging for discrimination of benign and malignant pelvic masses

Abstract

Objective. To cross-validate, prospectively, the diagnostic performance of established ultrasound methods for discrimination of benign and malignant pelvic masses. Methods. A total of 173 consecutive women with a pelvic mass judged clinically to be of adnexal origin underwent preoperative ultrasound examination including color and spectral Doppler techniques. A total of 149 tumors were benign, and 24 were malignant. The sensitivity and false-positive rate with regard to malignancy were calculated for the following methods, using cut-off values recommended in previous publications: Lerner score; ultrasound morphology, i.e. tumors without solid components being classified as benign and tumors with solid components as malignant; tumor color score; pulsatility index; resistance index; time-averaged maximum velocity; peak systolic velocity; the combined use of ultrasound morphology and tumor color score and the combined use of ultrasound morphology and peak systolic velocity. Sensitivity and false-positive rate were also calculated for subjective evaluation of the gray-scale ultrasound image and for subjective evaluation of the gray-scale ultrasound image supplemeted with subjective evaluation of color Doppler ultrasound examination. The confidence with which the diagnosis was made, based on subjective evaluation, was rated on a visual analog scale. Results. Subjective evaluation of the gray-scale ultrasound image was by far the best method for distinguishing benign from malignant tumors (sensitivity 88%, false-positive rate 4%), followed in descending order by subjective evaluation of the gray-scale ultrasound image supplemented with color Doppler examination, the Lerner score and the time-averaged maximum velocity. Adding Doppler examination to subjective evaluation of the gray-scale image did not increase the number of correct diagnoses, but it increased the confidence with which a correct diagnosis was made in 14% of tumors. In 11 tumors (6% of the series as a whole), the addition of Doppler examination changed the diagnosis based on subjective evaluation of the gray-scale ultrasound image from an incorrect (n = 1) or uncertain (n = 10) diagnosis to a correct and confident diagnosis. Conclusion. In experienced hands, subjective evaluation of the gray-scale ultrasound image is the best ultrasound method for discriminating between benign and malignant adnexal masses. The main advantage of adding Doppler examination to subjective evaluation of the gray-scale image is an increase in the confidence with which a correct diagnosis is made.