Diagnostic value of ultrasonography in patients with palpable mammographically noncalcified breast tumors

PURPOSE: To analyze the diagnostic accuracy of mammography, ultrasonography (US), and both methods combined in evaluation of palpable noncalcified breast tumors. MATERIAL AND METHODS: Mammograms and sonograms of 200 patients with palpable noncalcified breast masses were retrospectively analyzed independently by four experienced radiologists in 3 sessions: Mammography or US interpretations in the first two and combined reading in the last session. Nonneoplastic abnormalities and mammographically obvious cancers were excluded. Receiver operating characteristic (ROC) analyses were performed for 115 (60 benign and 55 malignant) tumors and subgroups according to tissue density and tumor size. A single ROC curve for each diagnostic test was obtained by pooling the individual ratings. The area under the ROC curve was used as a measure of diagnostic performance. RESULTS: US revealed significantly higher diagnostic performance than mammography for tumors larger than 2 cm. Combined reading showed significantly higher performance than mammography except for tumors smaller than 2 cm. The performance of all three tests was reduced in dense parenchyma, and significantly so for mammographic and combined interpretation. CONCLUSION: The accuracy of US in patients with palpable mammographically noncalcified and not obviously malignant breast tumors is lower than reported for mixed sample populations. The accuracy of US may be influenced by breast parenchyma density. Combined reading offers the highest diagnostic accuracy.