Veterinarians use many modes of imaging, from X-rays to computed tomography (CT) scans and magnetic resonance imaging (MRI). Each type employs different methods to create images, and each is best suited to distinct bodily components.

While CT and MRI units are rarely seen outside of large specialty practices, ultrasound technology is becoming more and more common, with many clinics using ultrasound machines on a daily basis for diagnosis and other procedures.

“Ultrasound, the same technology used to generate sonograms during human pregnancy, uses sound waves transmitted into the body to create an image,” says Dr. Drew Sullivan, who serves as medical director of the Medical District Veterinary Clinic at Illinois, a small animal clinic located in Chicago that is run by the University of Illinois College of Veterinary Medicine. Dr. Sullivan is certified in small animal ultrasound.

“Ultrasound is a very non-invasive modality that has no side effects, although occasionally mild sedation is needed to help an anxious patient remain still so a clear image can be captured,” says Dr. Sullivan.

Whereas radiographs provide an overall snapshot of an abdomen or a thorax, ultrasound does not offer a view of the entirety of region in the body. Ultrasound does, however, allow clinicians to look at the architecture of an organ, which can be very useful, according to Dr. Sullivan.

Another advantage of ultrasound is that it is faster and more affordable than some other advanced imaging modalities.

“Ultrasound can provide a lot of information for its cost and is often more readily available compared with other advanced imaging modalities such as a CT or MRI,” says Dr. Sullivan. “Using ultrasound and X-rays together form a great diagnostic tool.”

For example, when a pet has a tumor or ingests something it shouldn’t have, an ultrasound can be helpful to locate these objects and characterize them.

“Fluid can be distinguished from soft tissue masses or foreign bodies, which is sometimes difficult to differentiate on X-rays,” explains Dr. Sullivan about the process. Thus, ultrasound is a useful tool to diagnose patients for hemoabdomen and pericardial effusion, which are blood in the abdomen and around the heart, respectively.

“Being able to diagnose these conditions can be lifesaving in an emergency situation. Once we understand that there is blood in the abdomen or around the heart, we can attempt to remove this fluid and potentially save the patient,” explains Dr. Sullivan.

“Ultrasound is one way we can evaluate the function of the heart and diagnose specific heart diseases. With an echocardiogram—an ultrasound of the heart—we can evaluate how the blood is flowing as well as whether the heart valves are functioning properly during a heartbeat,” says Dr. Sullivan.

“I think that ultrasound technology is necessary for treating my patients appropriately on a daily basis,” he says. He finds ultrasound especially useful to rule out potential diagnoses such as bladder stones in a urinary tract infection. It can also be used for fine-needle aspirates, which are small biopsies of organs or masses, or to obtain urine from the bladder.

“Ultrasound improves the quality of veterinary diagnosis and care,” says Dr. Sullivan. As more clinicians begin to feel this way, ultrasound equipment may become as prevalent as radiograph machines in veterinary practices.