Recent advances in ultrasound imaging of breast lesions.

Ultrasonography works as an essential tool in diagnosing breast cancer. For mass screening of breast cancer, mammography is used worldwide as a main tool. However, in the screening of women with dense breasts and in detecting small cancer of the breast, ultrasonography is known to be more useful than mammography. Most Japanese women contract breast cancer in their 40s. Women in their 40s have more dense breasts than those in their 50s. It is expected that mass screening for breast cancer in the future will be done by a combined use of mammography and sonography. A randomized control trial of the combined use is being carried out at present in Japan. In recent years, the degree and distribution of tissue strain induced by tissue compression with an ultrasound device has enabled evaluation with color. The method, real-time tissue elastography, is used as an auxiliary tool in diagnosing diseases of various organs. Breast elastography images, classified into patterns and scores, have also begun to be widely used. Compared with conventional B-mode sonography, elastography is superior in specificity. Based on this fact, we have considered omitting available histological examinations for some breast lesions in the near future. Furthermore, elastography was useful in preoperative assessment of the margin of breast cancer. Further development of ultrasound elastography in the future is expected.