If you work with lizards, snakes, tortoises, or other reptiles, x-rays are an important diagnostic tool for these patients.
So, how does the process of radiographing reptiles differ from dogs and cats? Here are some helpful tips for reptile x-rays…
Considerations for Reptile Radiographs
Many reptiles are small in size compared to the average dog or cat. Thus, good quality radiographs with sufficient detail are required for images to be diagnostic. High detail films such as those used for mammography can be beneficial here.
At the same time, many reptiles have highly keratinized scales, or, in the case of chelonians (turtles and tortoises), a shell. These coverings can mean a higher power beam is required, which can also mean loss of detail for internal body structures. Fortunately, motion blur is not a common issue, though.
As with other species of pets, good general rules of radiography apply. This means taking a minimum of two orthogonal views to get a complete picture of the part(s) of the body being radiographed.
Indications for Reptile Radiography
With reptiles, clinical symptoms are often subtle, and exam findings are often non-specific. So, diagnostic tools such as radiographs are important for figuring out what’s going on and providing the best treatment.
With this in mind, full-body radiographs are beneficial for any reptile who is showing symptoms of illness.
Additional common indications may include evaluating…
Bone lesions, such as osteomyelitis, traumatic injuries, or metabolic bone disease such as nutritional secondary hyperparathyroidism.
The digestive tract, including looking for ingested foreign bodies or other digestive ailments.
Reproductive issues, such as dystocia, egg binding, or yolk coelomitis.
Abscesses and other soft tissue swellings.
Lung disease.
Urinary issues such as bladder stones.
Problems with other organs such as the heart or liver, although these organs may be difficult to evaluate in detail for many types of reptiles.
Assessing if intraosseous catheters are placed correctly.
Restraint for Reptile X-Rays
Fortunately, many reptiles hold still without restraint, or with limited restraint, for certain x-ray views. But it’s still important to have a plan in place to ensure quality, diagnostic images are obtained.
A few examples of restraint for different reptile species may include…
For snakes, allowing them to crawl inside a plastic tube. This also prevents coiling (which may interfere with radiographic interpretation) and ensures the snake is evenly extended for their radiographs.
Cardboard boxes or other radiolucent containers for smaller species, especially small lizards. Note that this may result in a minor reduction in details/image quality.
Vagal response in large lizards, which means placing pressure over the eyeballs when the lizard’s eyes are closed. This stimulates the vagus nerve, resulting in a lower heart rate and a calmer lizard. A vagal response could be accomplished with gentle digital pressure, or by placing cotton balls over the eyes and holding them in place with VetWrap wrapped around the head. Dimming the lights and avoiding any noise stimulation will also help.
Chemical restraint if indicated. This could mean sedation or general anesthesia, depending on how challenging the patient is to work with, what information needs to be obtained from radiographs, and the health status of the patient. Be sure to check the best sedative drugs and doses for the particular reptile species you are working with.
Common Radiographic Views for Reptiles
As mentioned above, it’s important to obtain orthogonal x-ray views. Often, due to the smaller size of many reptiles, this means orthogonal views (a lateral and a DV) of the entire body.
It’s important to remember that reptiles don’t have a diaphragm. They have a coelomic cavity, rather than separate abdominal and thoracic cavities like mammals have. Because of this difference, placing a reptile (except for snakes) in lateral recumbency may result in coelomic contents shifting, which can confound radiographic interpretation.
To prevent this issue and view organs in their natural position, many veterinarians obtain lateral radiographs of reptiles using a horizontal beam while the animal is standing.
For chelonians, it helps to place them on some type of stand by balancing the plastron on a block, overturned bucket, etc. This facilitates the horizontal beam view and encourages the patient to hold still and extend their limbs and head from their shell.
Additionally, the horizontal beam can be used to obtain a craniocaudal view in chelonians. This allows comparison of the right and left lung fields.
Contrast agents, such as barium or iodine-based contrast, may be used, especially when evaluating the GI tract. However, it’s important to keep in mind that digestive transit times are highly variable (within a day at the shortest, and weeks at the longest) depending on the species, their nutritional status, and environmental conditions such as temperature and season.
If more detailed radiographs of the skull or extremities must be obtained, it’s important to collimate. For some species, veterinary dental films may provide better detail. Anesthesia may be needed for chelonians to fully view the skull or extremities outside of the shell.
Conclusion
Radiographs are a key tool when assessing reptiles for disease or injuries. But it’s important to understand the wide range of species variations in anatomy and become familiar with what’s normal and what’s not for each type of patient. This could mean having a good reference text, obtaining additional CE, or radiographing a healthy patient of the same species for comparison.
Once the best strategies and techniques are incorporated, diagnostic images can help a practitioner evaluate these unique pets and form an appropriate treatment plan.
Written by: Dr. Tammy Powell, DVM