Ultrasound imaging uses sound waves to produce pictures of the inside of the body. This happens when high-frequency sound waves are transmitted from a hand-held wand ("probe") through gel that's placed directly on the body. The probe collects the sounds that bounce back and a computer uses the sound waves to create an image.
Ultrasound images are captured in real-time and can show the structure and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound is noninvasive (the physician doesn't need to open up your body through biopsy or surgery to use it) and does not use the ionizing radiation that’s used in x-rays.
Ultrasound can be used to help diagnose the causes of pain and swelling and infection in the body’s internal organs. It is most commonly used to examine a baby in pregnant women. It’s also used to help guide biopsies, diagnose heart conditions, and assess damage after a heart attack. An ultrasound can also be used to image dense breast that a mammograph has trouble imaging.