OUTLINE: This is a diagnostic study. Patients receive ultrasound contrast agent IV. An ultrasound probe with Power Doppler facility is swept over the skin surface in a standard fashion before and after contrast enhancement. Blood flow data is acquired over the volume of the mass and/or lymph nodes using a video recorder. The scanning time ranges between 5 to 15 minutes depending on the size and exact location of the breast mass and axillary lymph nodes. Within 1 week of the ultrasound, patients undergo surgery and the mass and axillary lymph nodes are removed.