Ultrasound imaging, also called ultrasound scanning or sonography, is a method of obtaining images of internal organs by sending high-frequency sound waves into the body. The reflected sound waves' echoes are recorded and displayed as a real-time visual image. No ionizing radiation (x-ray) is involved in ultrasound imaging.

For example, an abdominal ultrasound image is a useful way of examining internal organs, including the liver, gallbladder, spleen, pancreas, kidneys and bladder. Because ultrasound images are captured in real time they can show movement of internal tissues and organs and enable physicians to see blood flow. This can help to diagnose a variety of conditions and to assess damage caused by illness.

What are some common uses of the procedure?

Ultrasound imaging is used extensively for evaluating the kidneys, liver, gallbladder, pancreas, spleen and blood vessels of the abdomen. Because it provides real-time images, it can also be used to:

• Guide procedures such as needle biopsies in which needles are used to sample cells from organs for laboratory testing.
• Help a physician determine the source of many abdominal pains, such as an inflamed appendix or stones in the gall bladder or kidney.
• Help identify the cause for enlargement of an abdominal organ.

Doppler ultrasound is a special type of ultrasound study that examines major blood vessels. These images can help the physician to see and evaluate:

• Blockages to blood flow, such as clots.
• Buildup of plaque inside the vessel.
• Congenital malformation.

With knowledge about the speed and volume of blood flow gained from an ultrasound image, the physician can often determine whether a patient is a good candidate for a procedure like angioplasty.

How should I prepare for the procedure?

You should wear comfortable, loose-fitting clothing for your ultrasound exam. Other preparation depends on the type of examination you will have. For some scans your doctor may instruct you not to eat or drink for as many as 12 hours before your appointment.