What you can expect

Before the procedure

Before your ultrasound begins, you may be asked to do the following:

• Remove any jewelry from the area being examined.
• Remove some or all of your clothing.
• Change into a gown.

You'll be asked to lie on an examination table.

During the procedure

Gel is applied to your skin over the area being examined. It helps prevent air pockets, which can block the sound waves that create the images. This water-based gel is easy to remove from skin and, if needed, clothing.

A trained technician (sonographer) presses a small, hand-held device (transducer) against the area being studied and moves it as needed to capture the images. The transducer sends sound waves into your body, collects the ones that bounce back and sends them to a computer, which creates the images.

Sometimes, ultrasounds are done inside your body. In this case, the transducer is attached to a probe that's inserted into a natural opening in your body. Examples include:

• Transesophageal echocardiogram. A transducer, inserted into your esophagus, obtains heart images. It's usually done while you are sedated.
• Transrectal ultrasound. This test creates images of the prostate by placing a special transducer into the rectum.
• Transvaginal ultrasound. A special transducer is gently inserted into the vagina to get a quick look at the uterus and ovaries.

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, or inserts it into your body.

A typical ultrasound exam takes from 30 minutes to an hour.