Ultrasonography of breast lesions detected in mammography screening.

Mammography screening was carried out in 18,012 women (aged 50-59) of whom 579 (3.21%) had to be recalled for clinical mammography. After completion of the clinical mammography each woman also had ultrasonography (US) with a hand-held real-time apparatus using a 7.5 MHz probe. There were 79 verified breast cancers; 32 of these were palpable and were also depicted at US, but only 29 (61.7%) of non-palpable breast cancers (n = 47) were found at US. Twenty-two of the non-palpable breast cancers were seen at US as a tumor-like lesion, 2 because of local echo-architecture distortion, and 5 only because of acoustic shadowing. The US image did not help to differentiate between malignant and benign lesions.