An ultrasound (also referred to as a sonogram) is a non-invasive, pain-free procedure used to evaluate the internal organs in pets without having to perform surgery.  Ultrasound equipment directs a narrow beam of high-frequency sound waves into the area of interest. The sound waves may be transmitted through, reflected or absorbed by the tissues that they encounter.

The ultrasound waves that are reflected will return to the probe as “echoes,” and are converted into an image that is displayed on the monitor, giving a 2-dimensional real-time “picture” of the tissues under examination.

When Are Ultrasounds Used?

Ultrasound is invaluable for the examination of internal organs and was first used in veterinary medicine for pregnancy diagnosis. However, ultrasound has become extremely useful in evaluating the:

  • abdominal organs
  • certain structures in the neck
  • the heart (echocardiogram)
  • eyes
  • muscles/tendons
  • reproductive organs

For many abdominal disorders, both ultrasound and X-rays are recommended for optimal evaluation. The X-ray shows the size, shape and position of the abdominal contents, and the ultrasound allows the veterinarian to see inside the organs.

An abdominal ultrasound is indicated to evaluate pets with abdominal symptoms such as vomiting, diarrhea, straining to urinate or urinating blood. This test can also be helpful in cases of reproductive abnormalities, unexplained fever, loss of appetite or weight loss. An abdominal ultrasound is often done if an X-ray, blood tests, or physical examination indicate a problem with an abdominal organ such as the liver, spleen, or pancreas. If physical examination reveals abdominal pain or enlargement of an abdominal organ, ultrasound examination could be indicated. As with people, the abdominal ultrasound can also be used to detect early pregnancy and determine the viability of the fetus later in the pregnancy

What Does an Ultrasound Involve?

An abdominal ultrasound exam involves imaging the abdominal organs which helps in the evaluation and detection of changes in the size, shape, tissue density, internal structure and position of organs including the liver, spleen, kidneys, gall bladder, stomach, intestines, adrenal glands, pancreas, bladder, prostate, lymph nodes, ovaries, and uterus.

An abdominal ultrasound is an excellent diagnostic test and is noninvasive and painless. However, as with all tests, it is neither 100 percent sensitive or specific. In some cases, additional diagnostic procedures will be needed to diagnose an abdominal problem.

At Roanoke Animal Hospital, we perform abdominal ultrasounds as well as ultrasounds of the neck to examine thyroid and parathyroid glands.  Although ultrasound waves are unable to pass through air, occasionally, we will use the ultrasound to locate a mass in the lungs.

In some cases, it may be advisable to aspirate (suction via a very fine gauge needle) fluid or cells from cavities or tissues within the body using the ultrasound to guide the needle which enhances accurate sampling and improves safety. If this procedure is performed, we typically recommend a sedative or anesthesia.

More FAQs About Ultrasound for Pets

How Is an Abdominal or Neck Ultrasound Performed in Pets?

Specialized equipment is required to perform an ultrasound exam. The pet is placed on his/her back on a padded table or cushion so the abdominal surface or underside of the neck is exposed to the examiner. The hair on the abdomen or neck is shaved and a conductive gel is placed on a probe (transducer) that is attached to the ultrasound machine. The examiner places the probe on the skin of the abdomen or neck and moves it across the surface to examine the organs or regions of interest.

Is an Ultrasound Painful?

Ultrasound is a very safe, non-painful and non-invasive procedure.  Unlike x-rays, which are potentially dangerous, ultrasound waves are considered to be safe.  The sound waves of the ultrasound machine are too high pitch for us, or any of our patients to hear, so there really are no harmful side effects or long-term health risks associated with using an ultrasound as a diagnostic tool.

Do I need to withhold food and water before my pet’s ultrasound?

Yes, in general, it is vital that you withhold food (water is acceptable) from your pet for roughly 8-10 hours before an abdominal ultrasound is performed because food in the stomach can limit the ability to see all the abdominal organs.  Withholding food is less of a concern when an ultrasound is being performed on the neck. However, should mild sedation or anesthesia be required for either ultrasound procedure, it is better if your pet does NOT eat at least 8-10 hours prior to an ultrasound procedure.  If your pet is currently on any medications or has a certain medical condition, we recommend you call our hospital and speak to a staff member to ensure different recommendations are not suggested. Your pet can have water available at all times prior to the ultrasound procedure.

Is Sedation or Anesthesia Needed for an Abdominal or Neck Ultrasound?

Most of the time, neither sedation nor anesthesia is needed.  Pet’s getting an ultrasound lie on their back on a padded table or cushion.   Veterinary technicians and assistants gently restrain pets for about 30 minutes during the examination.  However, some pets resent laying on their backs and may require some sedation to allow an ultrasound to be performed.  Should your pet require a mild sedative, we will contact or discuss this with you prior.

If a biopsy needle is used to obtain a tissue or fluids sample, a local anesthetic or ultrashort sedative or anesthesia may be required. Should your pet require a needle biopsy and sedation is required, we will contact or discuss this with you prior.

Is it necessary to shave my pet's fur?

In most cases, the fur must be shaved to perform an ultrasound examination. Since ultrasound waves are not transmitted through air, it is imperative that the hand-held probe makes complete contact with the skin. In some cases, such as pregnancy diagnosis, it may be possible to get adequate images by moistening the hair with rubbing alcohol and applying a copious amount of ultrasound gel.

When will I know the results of the examination?

Since an ultrasound study is performed in real-time, the results of what is seen are known immediately. In some cases, the ultrasound images may be sent to a veterinary radiologist for further consultation. When this occurs, the final report may not be available for a few days.