Ultrasound detects cancers in about 0.40% of women with mammography-negative dense breasts, with a higher contribution in women younger than 50 years. However, false positives are a major concern in screening ultrasound. Several approaches to ultrasound interpretation and breast imaging management have been developed that substantially reduce the frequency of false-positive cases, involving both recall examinations and biopsies, without meaningfully reducing the detection of nonpalpable favorable-prognosis cancers.
Successful methods to reduce the recall rate for screening ultrasound involve (1) obtaining clinical history and physical examination information, (2) confidently and correctly identifying some normal structures and artifacts, and (3) learning to ignore subtle sonographic findings of doubtful significance. Procedure-related changes including fat necrosis and foreign body can be ignored with the proper history. Fat lobule often mimics solid nodule and Cooper's ligament produces architectural distortion and shadowing. Dilated ducts without intraductal masses are incidental benign findings. Complicated cysts can mimic solid nodules. They are nonparallel orientation and often show curvilinear bright line of anterior wall. Oval circumscribed solid masses less than 1cm in size can be followed.
Doppler ultrasound and elastography can help distinguish normal or benign from suspicious solid masses. When a breast lesion categorized as BI-RADS 3 or 4 shows a normal strain on elastography and no vascularity on color Doppler ultrasound, biopsy can be averted. Physicians performed the screening ultrasound could directly evaluate lesions in real-time and reduce patient anxiety and discomfort. By applying these approaches successfully, we will be able to demonstrate convincingly that the benefits of ultrasound far outweigh the risks of false-positive interpretations.