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)
- 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.