Comparison of the diagnostic performance of high-frequency ultrasound as a first- or second-line diagnostic tool in non-palpable lesions of the breast.

To compare the diagnostic performance of high-frequency ultrasound (HFU) as a first- or second-line diagnostic tool in non-palpable lesions (NPL) of the breast and to define the place of HFU in the diagnostic process, 89 women with this kind of lesion, previously detected by mammography, underwent HFU with 7.5-13 MHz transducers. The examinations were performed by two equally experienced operators of which only one (operator I) was aware of the mammographic findings. The mammographic examinations revealed the following non-palpable lesions: asymmetry-hyperdensity (17 cases), nodule (44 cases), stellate lesion (5 cases), microcalcifications (23 cases). Total sensitivity of HFU in the examinations performed by operator I was 83 %, while in the examinations performed by operator II (unaware of the mammographic findings) it was only 35 %. In all cases HFU allowed the operators to determine the basic features of the lesions. Our experience confirms that ultrasonography, even if performed with high frequency, cannot be proposed as a screening examination but may profitably be employed as a second-step technique to characterize NPL previously identified by mammography. This 'second-step' role can do the following: rule out true pathology (cases of false-positive mammography findings); furnish some basic features in the case of focal lesions; show other findings in the case of microcalcifications, such as microcysts, 'filled duct' appearance, parenchymal inhomogeneities and nodules; guide interventional procedures; and localize lesions preoperatively.