Ultrasound, also referred to as sonography and ultrasonography, uses high frequency sound waves to create an image of some part of the inside of the body.
A trained technologist (sonographer) presses a small, hand-held device (transducer), about the size of a bar of soap, against your skin over the area being examined, moving it as necessary to capture the image. The transducer sends sound waves into your body, collects sound waves that bounce back and sends them to a computer, which creates the images.
The preparation for the test will depend on the type of ultrasound test that your doctor has ordered. Some preparations include drinking a quart of water prior to the test to obtain better images. Other preparations may include fasting or eating a fat-free dinner the night before. You will be provided with complete instructions when your exam is scheduled.
You may need to remove jewelry and some or all of your clothing, change into a gown and lie on an examination table. A warm, water soluble gel is applied to your skin over the area to be examined. The gel does not stain your clothes or harm your skin.
Ultrasound is usually painless. However, you may experience mild discomfort as the sonographer guides the transducer over your body, especially if you're required to have a full bladder.
A typical ultrasound exam lasts 30 minutes to an hour.