Ultrasound is used to confirm and monitor pregnancies and also to carry out detailed examinations of the heart, liver and other abdominal organs without the risk of general anaesthetic or surgery.
Ultrasound offers a non-invasive, non-painful method for the diagnosis and staging of many diseases. It is the best method to evaluate fluid filled and soft tissue organs. Because ultrasound will not penetrate through air, ultrasound cannot be used to evaluate abnormalities if they are surrounded by gas.
Why Ultrasound?
Ultrasound allows us to visualise the internal architecture of many organs using sound waves.
Internal abnormalities such as nodules, masses, cysts and abscesses that are inapparent on x-rays can not only be seen, but can be counted and measured.
Although the ultrasound examination alone is in many cases non-specific for a particular disease, in conjunction with the animal's age, sex, breed, history, physical exam, radiographic findings and lab work, as well as ultrasound guided fine needle aspirates or true-cut biopsies, the specificity for disease can be high.
Many organs that are difficult to see on plain film radiographs (prostate) can be seen with ultrasound. Real-time echocardiography (ultrasound examination of the heart) also allows us to see the heart in motion. From these images, measurements of abnormal motion can be compared to normal values.
How is an Ultrasound performed?
The typical ultrasound examination requires no anaesthesia and is easily performed on awake animals. The only patient preparation necessary is clipping of the hair overlying the area to be scanned (the ultrasound will not penetrate through hair) and placing coupling gel on the skin surface just prior to the exam process. The entire scanning process takes 30-40 minutes. Images are acquired on the monitor of the ultrasound machine as well as on film for later viewing.
What Can I See With Ultrasound?
Ultrasound is best at diagnosing abnormalities that are discrete. An example of this type of lesion would include a mass (tumor) in the liver. Once found, the mass can be measured for later comparison.
Ultrasound is used to diagnose a variety of both benign and malignant diseases such as the presence of stones within the urinary bladder, kidneys or gall bladder, infection of the gall bladder, urinary bladder, prostate or kidneys, the presence of enlarged lymph nodes, abnormal blood vessels, or free fluid within the abdomen. It is especially good in diagnosing disease of the pancreas (pancreatitis), adrenal abnormalities, urinary bladder wall tumors, uterine infections (pyometra) and masses that are located behind the eyeball (retrobulbar masses).
In animals with a history of vomiting, ultrasound can be used to evaluate if the problem is within the liver, gall bladder or pancreas. It can often diagnose problems that are associated with the stomach or small intestinal wall, or see an intestinal foreign body, thus preventing a labor intensive and costly exploratory surgery.
The diagnosis of pregnancy and fetal viability (heartbeats) are commonly seen by 21 days post-conception with ultrasound, which is much earlier than can be done with x-rays (42 days).
In the heart, ultrasound is at it's best, as the heart is fluid filled organ. Abnormalities such as a diseased heart muscle (hypertrophic and dilatory cardiomyopathy), fluid around the heart (pericardial effusion), and congenital abnormalities can be diagnosed and the severity can be assessed. Heartbase tumors, which are rarely seen on radiographs, can be visualized with ultrasonography. Ultrasound can easily differentiate fluid from a mass.
Recently, ultrasound has been used to evaluate tendon abnormalities of the shoulder and knee (stifle). Ultrasound often diagnoses problems earlier than would otherwise be possible. This a better chance of successful treatment.
Why am I Being Referred?
Although ultrasound capability is found in many general small animal clinics, many cases require the animal to be scanned (or re-scanned) by a registered specialist with training in ultrasound.
Many diseases can be diagnosed using ultrasound by your family veterinarian. Occasionally, however, there are questionable findings or the diagnosis is not "clear-cut" and a second opinion is in the best interest of the animal patient. This process is similar to human medicine where, for example, a family practitioner will perform the initial ultrasound examination, but for a number of reasons may then refer you to a radiologist who is specifically trained in ultrasound, to get a second opinion.