Until recently, ultrasound has been viewed primarily as an adjunct to mammography for the characterization of identified breast masses as cystic or solid. With the development of high frequency linear array transducers and computer-enhanced image capabilities of modern-day ultrasound equipment, clinicians have recognized the vastly expanded potential for use of ultrasound in the diagnosis and management of breast disease.

Not only can ultrasound now identify and characterize cysts as small as 3 mm in diameter but it can be utilized to access and biopsy those lesions identified as solid with an accuracy that equals and sometimes surpasses the much more uncomfortable procedure of mammography. In those patients with a negative or nonspecific mammogram and a difficult physical exam, ultrasound may help to support the benign nature of an otherwise questionable area or identify and confirm the malignant nature of a palpable but mammographically obscure lesion.

Ultrasonically defined solid lesions can be described in terms of not only size but shape, acoustic shadowing phenomenon, margin definition, compressibility and relationship to surrounding tissues which may allow separation into obviously benign or suspicious categories. The real time capability of ultrasound allows quick access for either fine needle or core needle biopsy and immediate confirmation of success of biopsy.

Another area of breast pathology that has previously thought to be best approached radiologically with ductography is nipple discharge. However, ductography is limited by the need to express fluid at the time of the exam and the limited ability to cannulate the duct in question. Ultrasound is an excellent alternative in the evaluation of these patients. By maintaining the transducer in a radial orientation to the nipple, the dilated fluid filled duct can usually be identified and in experienced hands intraductal papillomas can be detected.

Ultrasound is the preferred imaging modality when evaluating the breasts of women prior to mammographic age. The lack of ionizing radiation exposure makes ultrasound essential in assessment of breast lesions in pregnant women. By avoiding compression, ultrasound allows the comfortable evaluation of postoperative fluid collections, post-traumatic hematomas and abscesses as well as directing easy aspiration or biopsy.

While not widely used in the United States, whole breast "screening" ultrasound is currently used in several European countries. This technique may be appropriate for screening select women such as those with very dense breast in which mammographic lesions might be missed and particularly when such women have difficult physical examinations and strong family histories for breast cancer.

As ultrasound techniques and equipment become more sophisticated and are incorporated into the training of medical specialists outside of the Radiology suite, the patients with breast pathology should expect ultrasound to be part of every evaluation as an extension of the physical exam. It is incumbent on those physicians engaged in the evaluation and treatment of breast disease to fully use these new capabilities for the safety and comfort of our patients.

INDICATIONS FOR ULTRASOUND IN THE TREATMENT OF BREAST DISEASE

Differentiating cystic from solid lesions

Evaluating palpable but mammographically obscure lesions

Characterization of solid lesions as benign or suspicious

Evaluation of nipple discharge

Breast lesions in pregnancy

Breast evaluation in young women

Evaluation of the postoperative or painful breast

Identification of breast implant rupture

Screening for patients with dense or mammographically difficult breasts

Direction of fine needle, core needle or open biopsies