Imaging of the breast: techniques and results.

Procedures for imaging of the breast have increased in number substantially in the past 30 years. Mammography, currently the most important breast imaging technique, was introduced at the Mayo Clinic in 1961. In 1988, more than 36,000 mammographic procedures were done. Breast ultrasonography is also a valuable examination, particularly for determining whether mass lesions are cystic or solid. The use of mammography for screening is increasing. Screening mammography allows the detection of breast cancer before it is palpable and while it is still in a stage known as minimal breast cancer. Lesions metastatic to axillary lymph nodes are less common in women with nonpalpable breast cancers than in women with palpable lesions. Nondiagnostic mammography should not delay the biopsy of a mass that is suspicious on physical examination. A special breast imaging center for performance of screening studies and evaluation of breast problems has been established at the Mayo Clinic.