The Pet Owner's Guide to Veterinary Ultrasound

Some diagnoses of certain pet health conditions need the use of a veterinary ultrasound machine. Veterinary ultrasound is painless, non-invasive and does not involve any ionizing radiation unlike some other veterinary diagnostic equipment, such as x-rays. However, this procedure is expensive to use and can cost between $300 to $500 depending upon the extent of the procedure and whether it was done at a pet hospital or at a veterinarian's office.

How Does An Ultrasound Machine Work?

An ultrasound machine uses sound waves to penetrate internal organs rather than radiation as in the case on x-rays (contrast veterinary radiology). These sound waves are transmitted at a much higher frequency than we can hear. Depending upon the density of the material the sound waves hit, they reflect back in greater or lesser amount creating an image on a monitor of the machine, which resembles a computer screen. A hand-held probe is placed above the location for viewing. This probe transmits and then receives the reflected sound waves. The computer analyzes the amplitude and time delay of the returning sound waves and forms a computerized image that it displays on the screen using the amount of "round-trip" time in calculating the depth of the structure. Tissues and fluids reflect the sound the best while gas, bone or air prevents the transmission of the sound wave.

Since the pulses of sound and the images produced by them are updated approximately 30 times per second, organs can be seen as they are functioning. This allows the veterinarian to determine if an organ is functioning properly without surgery. For example, an echocardiogram, which provides ultrasound views of the heart, will show the heart as it is pumping. This will allow the veterinarian to determine if the heart is pumping enough blood per beat or if one its valves are defective. Detection of bladder or kidney stones, gallstones, fluid pockets, the thickness of organ walls, obstructions, cysts and even pregnancy can all be "seen" by the vet ultrasound machine. These images can be stored and printed as a photograph or even recorded on a computer or videotape.

Procedures Using Animal Ultrasound

Since air impedes ultrasound waves, any hair must be shaven away first. The fur will trap air and deflect the waves. Gel is applied on the area to be viewed to block out air between the receiver and the patient. Depending upon the length of the ultrasound procedure, if the pet is apprehensive about clippers or if a biopsy is necessary, sedation or anesthesia may be required.

Ultrasound is a safe, non-invasive tool allowing visualization of tissues not otherwise possible. It is safer and more economical than contrast radiography and shows more detail than x-rays. It can help confirm a diagnosis. Guided by the image of the ultrasound, a veterinarian can obtain a small tissue sample (biopsy) by making a small incision and inserting a needle and withdrawing fluid to be sent for analysis.