As zoo veterinarians, we recognize the importance of identifying animals with health problems as early as possible. Fortunately, the Detroit Zoological Society has exceptional zookeepers who attentively look after each animal in their care and alert the veterinary team whenever they suspect there may be a problem. While subtle changes in demeanor, appetite, fecal and urinary output, and activity level can be key indicators of illness in an animal, most of our patients are very good at hiding their symptoms. In order to get a more comprehensive understanding of an animal’s health, we often rely on diagnostic tests, such as physical examination, bloodwork and cultures for bacteria.
When the Ruth Roby Glancy Animal Health Complex opened in 2004, the radiology suite was equipped with a state-of-the-art radiology unit designed for use in human hospitals. With this upgrade, we found that we increasingly relied on diagnostic imaging (radiographs and ultrasound) to make diagnoses and shape our treatment plans. In fact, we take x-rays during almost every diagnostic examination, on patients as small as dart frogs and as large as bison.
Since the early 2000s, imaging technology has been rapidly advancing, and by upgrading equipment and adding new technologies, the Detroit Zoological Society has stayed on the cutting edge of veterinary care. This includes having ultrasound probes designed for patients of all shapes and sizes, digital dental radiography and portable x-ray equipment that can go out into the Zoo to image animals who are difficult to move to the hospital. Despite these advancements, we still found it necessary to take patients to off-site facilities at least a few times each year for computed tomography (CT) or magnetic resonance imaging (MRI).
In late 2019, two very exciting things happened: first, a generous donor named Thomas A. Mackey came forward with an interest in funding a project that would have an immediate impact on animal care and welfare, and, secondly, we became aware of a revolutionary new computed tomography (CT) technology that had been developed in Ann Arbor. One of the most important features of the new CT technology is that it is portable, and much more affordable and user-friendly than a full-sized CT system. Since our hospital was already equipped with the features and space necessary to install the new system, within just a few months, we were able to bring this exciting new technology to the Zoo.
The new Xoran Portable CT has been in use for only a few months, but it has already had a tremendous impact on patient care at the Detroit Zoo. Adding CT to our diagnostic toolbox has increased the level of care that we can provide to animals at DZS exponentially. CT works by aiming a narrow beam of x-rays at a patient, while quickly rotating around them. The CT’s computer generates cross-sectional images, or “slices” of the body. The images contain more detailed information than conventional x-rays. Once the slices are generated, they can be digitally “stacked” together to form a 3-D image that allows for easier identification and location of basic structures as well as possible tumors or abnormalities.
Here are just a few examples of how this technology is helping us give animals the best possible care:
CT imaging is especially well suited for visualizing the teeth and bones of the jaw. A male aardvark was due for a routine checkup. He had been eating fine, and there was no reason to suspect that he had dental disease. However, aardvarks often have problems with their teeth, so we decided to use the CT machine to scan his head. The images collected showed that he had areas of bone breakdown around the roots of three separate teeth. Treatment was able to be provided before his condition progressed to a point where he was showing signs of discomfort.
This adult McCord’s box turtle was imaged during a routine examination. The shell covering the body can make radiographs hard to interpret, but CT imaging allows us to see inside of the turtle.
McCord’s box turtle: a. Image of the head and forearms, b. image from the side showing the head and neck folded into the shell, c. 3D reconstruction of the face and front limbs seen in image a.
a. b. c.
CT imaging has also proved helpful for several avian patients. One of the cinereous vultures living at the Zoo had a mass (red star) growing on the toe pictured below. The mass needed to be removed, but in order to plan for surgery, we needed to understand if the mass was superficial or more invasive and involved the soft tissues and bone beneath. CT imaging provided better detail for seeing small changes in the muscles and ligaments surrounding the mass. After evaluating the images, we were able to plan a surgical approach to remove the mass, and any adjacent tissue of concern. The vulture is doing great post-operatively and already back in his home!
We currently have four red pandas living at the Detroit Zoo. The oldest is a 14-year-old female named Ta-Shi. During her recent routine examination, we noticed that one of her large molar teeth appeared darker than normal and was cracked on the surface. Within a few moments, we were set up and ready to collect CT images of her head and teeth. The images showed that the tooth was infected at the root, a problem that was likely causing discomfort. The tooth was also broken, meaning it needed to be removed in several pieces. After the tooth was extracted, a repeat CT showed us conclusively that all of the roots had been completely removed.
We are extraordinarily grateful to have state-of-the-art equipment at hand to care for animals at the Detroit Zoo. The recent financial gift that made the addition of CT possible has improved our ability to see small changes more clearly, detect problems earlier and fine-tune treatments. With this tool, we will continue to ensure that animals live long, healthy lives and thrive within our care. We cannot say thank you enough to Thomas A. Mackey for his incredibly generous donation!
– Dr. Ann Duncan is the director of animal health for the Detroit Zoological Society and oversees the Ruth Roby Glancy Animal Health Complex.