Wild and Neal(1) first described the use of ultrasound to examine the breast in 1951. Since that time, ultrasound technology has improved significantly. Now ultrasound is the most widely used and most effective adjunctive technique tomammography. Initially, ultrasound was mainly used for lesion characterization and to provide guidance for interventional procedures. Then, automated breast ultrasound was developed as a consequence of exaggerated concern about radiation risk from mammography. Several studies showed that ultrasound, at that time, failed to detect small cancers not evident on other modalities, such as mammography or even clinical breast examination. Tremendous improvements in ultrasound technology over the years, with the development of higher resolution probes, have meant improved quality of images. Breast ultrasound examinations are cheaper than examinations using MR imaging. Also, breast ultrasound poses no radiation risk during the examination. Furthermore, the breast ultrasound examination is a much more comfortable examination than examinations requiring a mammographic compression plate. However, the operator dependence of breast ultrasound, its small field of view, and the high likelihood of false-positive and false-negative findings have limited its application in breast imaging.