Breast ultrasound: current concepts.

Breast ultrasound plays a major role in the identification, diagnosis, and staging of breast cancer. Gray-scale (brightness mode) is the most common form of ultrasound used in breast imaging (BI); newer techniques such as harmonic imaging, Doppler imaging, three-dimensional (3D) ultrasound, and elasticity imaging have also been employed. Breast lesions that are initially identified on mammography and magnetic resonance imaging can be further characterized with ultrasound. Breast ultrasound can differentiate solid from cystic masses, suspicious from benign lesions, and abnormal from normal lymph nodes. Ultrasound can guide needle biopsy of suspicious breast lesions and lymph nodes. Breast ultrasound can also be valuable when staging breast cancer and can help to determine if there is multifocal or multicentric disease, and also if there is associated regional lymphadenopathy.