An ultrasound uses sound waves to create images of body parts. It is useful to image soft tissues of the body but not bone. It is easy to administer and can also be performed while the patient moves the imaged part (such as a shoulder or knee) in different positions. The ultrasound may be used to help guide a needle into a specific body tissue either for an aspiration, injection, or biopsy. A doctor who suspects that you have a blockage in the blood vessels of your legs or arms may prescribe an ultrasound test. An ultrasound uses high-frequency sound waves that echo off the body. This creates a picture of the blood vessels. This is a noninvasive test that has no side effects.
A clear jelly is applied to the skin over the blood vessels being tested. The technician uses a sensor that looks like a microphone. The sensor is placed against the skin and moved up and down across the area being tested. The technician will apply pressure every few inches to see if the blood vessels change their shape. The test takes about 30 minutes, and most people experience no pain or discomfort.