Diagnostic imaging in companion animals

Veterinary medicine has come a long way in its ability to diagnose and treat disease in our companion animals, and the diagnostic tools we have available to us have come a long way as well. In addition to our physical exam, we can run a myriad of laboratory tests, including blood work, urinalyses and cytological analyses, to name a few. These tests may provide us with clues as to the metabolic status and overall health of a patient, but in order to actually visualize their internal organs and structures, we rely on diagnostic imaging.

One modality of diagnostic imaging that most of us are familiar with is the standard radiograph, or X-ray. Radiography uses electromagnetic radiation to view the internal structure of a non-uniformly composed, opaque object. An x-ray can let us look inside a patient, at their skeletal system and abdominal and thoracic cavities. We can look at their bone structure and evaluate for fractures or joint dislocations. With an X-ray, we can get an idea of whether there is a mass or tumor in the chest or abdomen, or if there are any foreign objects within the stomach or intestinal tract. An X-ray can even give us an idea of the size of the heart and the health of the lung fields. Dental radiology is used to evaluate the oral cavity for pathology, including tooth-root abscesses and fractures.

As advanced as radiography has become, it still does not tell us the architectural make-up or functional capabilities of an organ. Ultrasound is a modality of diagnostic imaging that provides us an even deeper look into a patient’s internal-organ structure. The ultrasound machine sends out high-frequency sound waves, which reflect off body structures. A computer receives these reflected waves and uses them to create an image. Unlike with radiography, there is no ionizing radiation exposure with an ultrasound. This type of imaging can provide us with the architecture and dimensions of a mass on the liver or spleen, and help us plan our surgical approach. An ultrasound allows us to measure the thickness of the intestinal walls to provide a diagnosis of inflammatory-bowel disease, or to evaluate the integrity of tendons and ligaments. With an ultrasound, we can even obtain an evaluation of the heart, called an echocardiogram, and quantify how well the cardiac muscle is functioning.

In situations where an even more thorough evaluation of the body is needed, we can now utilize technology in our animal patients that has previously been reserved for human patients. These include magnetic resonance imaging (MRI) and computed tomography (CT). Although both MRI and CT scans require general anesthesia for our patients, the information they provide can be invaluable in obtaining an accurate diagnosis of disease.

MRI scanners use strong magnetic fields and radiowaves to form images of the internal structures of the body. MRI can be used to evaluate the musculoskeletal system, including the spinal column, joint cavities and soft tissues, the gastrointestinal system and the nervous system. MRI is the diagnostic tool of choice for evaluation of the central nervous system, including the brain and spinal cord, and allows us to locate congenital defects, tumors and degenerative changes.

A CT scan combines a series of X-ray views taken from multiple different angles, which are processed by a computer to create cross-sectional images of the bones and soft tissues. These images can even be combined to create three-dimensional images, providing much more information than plain X-rays.

Given the diagnostic capabilities available to us, we have the ability to provide our patients with the advanced medical and surgical care that they deserve. Please contact your veterinarian if you have any questions regarding diagnostic imaging.

Dr. Nicholle Hommel is an associate veterinarian at Society Hill Veterinary Hospital. For more information, call 215-627-5955 or visit www.societyhillvets.com.

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