A breast ultrasound is frequently used to evaluate abnormalities found with screening or diagnostic exams, or during a physician-performed clinical breast exam. Ultrasound is excellent at imaging cysts – round, fluid filled pockets inside the breast. High-frequency sound waves are transmitted from a transducer, or "wand," through the breast. These waves bounce, or "echo," off the breast to reveal abnormalities. This echo is picked up by the transducer and translated by a computer to create a breast image displayed on a computer monitor.