Diagnostic Imaging in Veterinary Medicine

At the beginning of the last century, x-ray technology helped bring medicine out of the Dark Ages. Instead of cutting into a body to visualize basic structure, x-ray energy could be sent through the body to look “inside”. The discovery was so important that the first Nobel prize in physics was awarded to Konrad Roentgen for this discovery.

Imaging in veterinary medicine has advanced greatly since the first diagnostic radiographs (x-rays images) were taken of pets just decades ago. Now there are a multitude of imaging tests available to help diagnose and treat diseases in our pets. These tests include radiography (x-rays), ultrasound, CT (or CAT) scans, and MRI scans. Each of these tests have their own advantages and disadvantages, and will provide the veterinarian with different information. Radiographs are available in most general veterinary practices and some have ultrasounds, but CT and MRI scans are normally performed only at large referral practices and Veterinary Colleges due to very high cost.

Radiography equipment and ultrasound are what we have at 11th Street Veterinary Hospital. I’ll have to wait for another article to talk about the truly amazing things an ultrasound can tell us about the heart and other internal organs. A radiograph, commonly called an x-ray, is a black and white two-dimensional image of the interior of a body. In a radiograph, an image is generated by passing energy waves through a particular structure or area, such as the chest or a limb, and the image is then captured. The old way captures the image on x-ray film that senses how much radiation passes through the structure and reaches the film much like an old black and white film camera. The denser a tissue is (such as bone), the whiter the image. Less dense structures, such as air in the lungs, allow almost all of the x-ray energy to pass through to the film, turning that area black. This was an amazing tool in veterinary medicine for many years. Unfortunately, there are limits to the sensitivity of the film. While it is good at showing dense bony structures, it loses some details when looking at soft (not bony) tissues.

In the past several years, many veterinary practices, including 11th Street Vet, have upgraded to digital radiography. The principles are similar, but the images are captured on a digital recording device and displayed on a computer. No x-ray film is used. These images are easy to store as well as to transmit to Veterinary Radiologists for evaluation just like your personal physician does. These systems are a much more expensive investments than the traditional film systems, but boy is it worth it. The sensitivity of digital radiology is far superior to traditional film systems. They can see greater detail in bony structures and differentiate soft tissues in a way that greatly enhances the diagnostic capabilities. To demonstrate the difference, I’ve included examples of film radiographs from before our digital system and more recent digital radiographs. I realize that very few of you who read this are trained in reading diagnostic images, but I believe you will be able to see the difference. In the film image, the soft tissue of the body is generally milky or very faint and hard to see. The digital image shows not only bone difference but many soft tissue variations and even the skin and hair.

In addition to the much greater detail it offers, an additional advantage that digital radiography offers is “tele-radiology” (tele-medicine for radiographs). It has decreased the time and distance barriers that previously hampered referring radiographs to a radiologist for reading by a specialist. In the past, mailing films to a radiologist meant a radiograph report turnaround of at least a few days and often longer. With tele-radiology, report turnaround is measured in hours and even minutes. Digital radiography systems generally require less radiation to produce a higher quality radiograph than film based systems thus making them safer. They are also much more environmentally friendly since they don’t require dark rooms that use hazardous chemicals to develop the film.

Just like the old film cameras have all but disappeared from the scene, film radiographs are also disappearing to make way for improved technology that allows your veterinarian to do a better job at caring for your furry family member. Remember, your family Veterinarian can help guide you through your pet’s care throughout their lives!