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An ultrasound is a safe and painless test using sound waves to get an image of different areas inside your body.

Your organs (heart, breast, stomach, liver, spleen, gallbladder, pancreas, kidneys, uterus, bladder, and thyroid—to name just a few) can be examined with ultrasound. This test can also be used to look at lymph nodes or blood vessels.

Images of the area of the body being looked at with the ultrasound equipment show up on a TV-like screen.

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How does an ultrasound work?

Ultrasound, also referred to as diagnostic medical sonography, utilizes high-frequency sound waves to produce images of structures within the body. The images can provide valuable information for diagnosing and treating a variety of diseases and conditions. Because ultrasound images are captured in real-time, they can also show movement of the body's internal organs as well as blood flowing through the blood vessels. Ultrasound does not use ionizing radiation (as used in X-rays) and is generally considered safe when used appropriately by trained professionals.

Ultrasound involves the use of a small transducer (probe) that transmits high-frequency sound waves into the body. The transducer collects the sounds that bounce back off the structures of the body, and the computer in the ultrasound machine then uses those sound waves to create an image.

How to prepare and what to expect

Patient experience

Preparation for the procedure will depend on the type of examination the patient will be having. Some examples of exam preps are:

  • Nothing to eat or drink (NPO), no gum chewing, and no smoking for several hours before the appointment.
  • Drink a certain amount of water to obtain a full bladder prior to the exam, and avoid urinating so that the bladder is full when the scan begins.
  • No prep needed

Ultrasound exams can typically last 20 to 75 minutes, depending on the type of information that has been requested by the physician.

Patients may be asked to change into a gown or remove jewelry in the area to be examined.

To capture images, the sonographer applies a small amount of ultrasound gel to the skin and moves the transducer over the skin in the area of interest. The gel will be removed at the end of the exam. When the exam is over, the sonographer will assist you from the table and out of the room. 

Before and after an ultrasound

Patient preparation

Patients must have complete insurance information with them, including a current insurance card.


Once the exam has been completed, the ultrasound images will be interpreted by a board-certified physician and the findings sent to the ordering provider. The ordering provider will contact the patient with results of the exam.

How an ultrasound helps

Ultrasound examinations can help to diagnose a variety of conditions and is used to evaluate symptoms such as: 

  • pain
  • nausea
  • swelling or enlargement
  • bleeding

Some typical uses for ultrasound examinations include, but are not limited to:

  • pregnancies
  • breast exams
  • internal organs (e.g., heart, gallbladder, liver, kidneys, thyroid uterus and ovaries)
  • external structures (e.g., breast, scrotum, skin lumps)
  • blood vessels (to check for blood clots and vessel narrowing)
  • ligaments (e.g., rotator cuff, Achilles tendon)
  • guidance for biopsies and injections

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Reviewed by: Kathleen Inveen, director, radiology

First published: 3/7/2017
Last reviewed: 2/22/2017