An ultrasound (also called a sonogram) is a non-invasive procedure used to evaluate the internal organs in dogs and other animals. Ultrasound examinations can be used to examine the abdominal organs, heart, eyes and 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. The abbreviation of US is commonly used for ultrasound.
An abdominal ultrasound is indicated to evaluate dogs 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 viability of the fetus later in the pregnancy.
Many veterinarians refer dogs needing an ultrasound exam to a specialty veterinary hospital because performing the procedure requires specialized skills and equipment. Some clinics do have ultrasound facilities on-site, and others use the services of mobile specialists who come to the clinic to perform ultrasound examinations. There is no real contraindication to performing this test. Even normal results help determine health or exclude certain diseases.
What Does an Abdominal Ultrasound Reveal in Dogs?
Abdominal ultrasound helps in the evaluation of abdominal organs including the liver, spleen, stomach, intestines, kidneys, bladder, uterus and prostate gland. This test can be extremely useful for detecting changes in the shape, size, tissue density, internal structure, and position of organs. The exam also can identify most abdominal masses or tumors, abdominal fluid, and abnormal lymph nodes. Frequently abnormal tissue or fluid is sampled with a needle or biopsy instrument using the guidance of the ultrasound exam.
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 such as endoscopy (scoping), contrast X-ray with barium or intravenous contrast (dye) study will be needed to diagnose an intra-abdominal problem. The last resort in most cases of unexplained abdominal disease is an exploratory surgery.
How Is an Abdominal Ultrasound Done in Dogs?
Specialized (and very expensive) equipment is required to perform an ultrasound exam. The hair on the abdomen needs to be clipped. The pet is placed on a padded table and held so the abdominal surface is exposed to the examiner. 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 and moves it across the surface to examine the organs or regions of interest. Ultrasound waves are transmitted from the probe and are either absorbed or echo back from internal organs. Based on how many sound waves are absorbed or reflected, an image of the internal organs is displayed on a computer screen. With proper training and sufficient experience, the sonographer (examiner) can create consistent images of the internal organs and recognize departures from normal. Abdominal ultrasonography is a safe procedure and generally takes about 20 to 60 minutes to complete. The only risk involved occurs during fine needle aspiration or biopsy of suspected lesions (diseased tissues). Rarely, biopsy will lead to serious bleeding or damage to an internal organ. However, the procedure is far safer and less invasive than an exploratory surgery of the abdomen.
Is an Abdominal Ultrasound Painful to Dogs?
No pain is involved. The procedure is noninvasive.
Is Sedation or Anesthesia Needed for an Abdominal Ultrasound?
Neither sedation nor anesthesia is needed in most patients; however, some dogs resent laying on their backs and may require some sedation to allow a diagnostic procedure. If a biopsy needle is used to obtain a tissue sample, a local anesthetic or ultrashort anesthesia is used.