Parallel vessels as a predictor of benignity in solid breast masses.

To evaluate the presence of a parallel artery and vein on color Doppler ultrasound as a predictor of benignity in solid breast masses. This prospective study included all patients with solid breast masses identified by ultrasound at our center from January 2012 through December 2015. All masses were studied with B mode and color Doppler ultrasound. We calculated the sensitivity, specificity, positive predictive value, and negative predictive value, and their respective 95% confidence intervals for the parallel vessel sign against the histologic findings or 2 years' follow-up without changes. A total of 526 solid masses were included in the 3-year period; the parallel vessel sign was observed in 377 (71.6%). We found 74.8% (95% CI: 70.9-78.7) sensitivity, 65% (95% CI: 50.2-79.7) specificity, 96.2% (95% CI: 94.3-98.1) positive predictive value, and 17.5% (95% CI: 11.4-23.6) negative predictive value. Of the 379 masses classified as breast imaging reporting and data system (BI-RADS) 3, the parallel vessel sign was observed in 275 (72.5%); all of these were definitively benign. Of the 109 masses classified as BI-RADS 4, the parallel vessel sign was observed in 89 (80.7%); 88 (98.8%) of these were definitively benign. Of the 38 masses classified as BI-RADS 5, the parallel vessel sign was observed in 13 (34.2%); all of these were definitively malignant. The parallel artery and vein sign is a good predictor of benignity, although it must be analyzed together with other morphologic descriptors.