Ultrasound imaging

Ultrasound is a test that uses reflected sound waves to produce an image of organs and other structures in the body. It does not use X-rays or other types of possibly harmful radiation.

For ultrasound testing, gel or oil is applied to the skin to help transmit the sound waves. A small, handheld instrument called a transducer is passed back and forth over the area of the body that is being examined. The transducer sends out high-pitched sound waves (above the range of human hearing) that are reflected back to the transducer. A computer analyzes the reflected sound waves and converts them into a picture that is displayed on a TV screen. The picture produced by ultrasound is called a sonogram, echogram, or ultrasound scan. Pictures or videos of the ultrasound images may be made for a permanent record.

Ultrasound is most useful for looking at organs and structures that are either uniform and solid (such as the liver) or fluid-filled (such as the gallbladder). Mineralized structures (such as bones) or air-filled organs (such as the lungs) do not show up well on a sonogram.

An ultrasound is done for several reasons. It may be used to look for a blocked blood vessel. It may be used to find the cause of pain in your belly or another part of your body. Or it can be used to look for a cyst, tumor, or abscess that may need treatment. It may also be used to help guide the placement of a needle or other tool during a biopsy.

This test is done in an ultrasound room in a hospital, clinic, or doctor's office.

• Gel is applied to the skin to help the sound waves pass through.
• The transducer will be pressed against the gel on your skin. It will be moved across your skin several times.
• You need to be very still while the test is being done.

In general, there's nothing you have to do before this test, unless your doctor tells you to. Depending on what is being looked at, you may get special instructions such as when you can eat or drink.

The scans from the test will be read within a short time.

Normal:

• The organs, tissues, and vessels are normal in size, shape, and structure.
• No growths, tumors, fluid, or other problems are seen.
• No signs of disease, inflammation, or infection are seen.
• Blood vessels and blood flow are normal. No blood clots are seen.

Abnormal:

• The organs, tissues, and vessels may be abnormal in size, shape, or structure.
• Growths, tumors, or fluid may be seen.
• Signs of disease, inflammation, or infection may be seen.
• Blockages in blood vessels, changes in blood flow, or blood clots may be seen.