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Diagnostic Imaging for Your Dog or Cat

Diagnostic Imaging for Your Dog or Cat

Is your dog or cat scheduled to have a diagnostic imaging test? You may be wondering how the appointment will go and how you can prepare. Here, our Gaithersburg vets explain what you can expect when you bring your dog in for a CT scan, MRI or ultrasound at our veterinary diagnostic lab.

About CT Scans, MRIs & Ultrasounds on Cats & Dogs

Also referred to as a CT or cat scan, computed tomographic imaging works by capturing multiple individual images or "slices" throughout a region of interest in the body through the use of radiation (X-rays) and a computer. 

The image a CT scanner produces can be compared to one individual slice of bread that's part of an entire loaf. The CT machine produces two-dimensional slices of a section of your pet's anatomy, then reconfigures them to a complete image that a veterinary specialist can see. 

These slices can also be used to create three-dimensional reconstructions that can be used to help plan surgeries. Once the images are produced, your veterinary specialist can review and interpret them. 

An ultrasound is a safe, non-invasive imaging technology that transmits sound waves into an animal's body to produce an image of specific internal structures. They allow a vet to assess organ function in real-time, evaluate blood flow, perform rapid traige assessment in an emergency, and more. 

MRI (magnetic resonance imaging) scans can provide your veterinarian with detailed, high-resolution images of your cat or dog's soft tissues, such as the brain, spinal cord, tendons, ligaments, and abdominal organs. 

What Can Dog or Cat CT Scans, MRIs and Ultrasounds Help Vets Diagnose?

Frequently used in both human healthcare and veterinary healthcare, these diagnostic tools are used to diagnose different conditions or illnesses depending on an animal's needs. 

CT Scans

A CT machine produces high-resolution images, which allows for a detailed evaluation of your pet's anatomy that would not be possible with standard X-rays.

CT scanners provide a clear view of the soft and bony structures in your pet's body, including the spine, nasal cavity, musculoskeletal system, thorax, and extra-thoracic structures. They can be used to evaluate: 

  • Nasal disease
  • Lung cancer 
  • The extent of canine and feline cancers
  • Ear disease
  • Pulmonary pathology 
  • Vascular abnormalities
  • Musculoskeletal and bone disorders, such as fractures or bone tumors 

CT scans can be used to help plan and facilitate surgery and minimize surgery time, which is important for pulmonary and liver tumors. 


Veterinary MRIs can produce a more detailed image of your pet's body than other diagnostic imaging tools, such as X-rays or CT scans, for many types of soft tissue injuries or diseases. An MRI may be useful in these situations:

  • To better visualize internal organ abnormalities
  • To identify issues with the brain and spine (brain tumor or inflammation, spinal disc tumor, herniated discs, stenosis)
  • Examination of the nasal cavity, sinuses and ears 
  • To diagnose musculoskeletal diseases and injuries (e.g. shoulder instability, ruptured cranial cruciate ligament) 
  • In cases where a simple X-ray or ultrasound did not reveal enough information to make a diagnosis

MRIs typically take about 45 minutes to an hour to complete and can provide critical diagnostic information about your pet's condition. 


Ultrasounds allow us to distinguish foreign bodies, fluid and soft tissue masses from one another — a task that may prove difficult to achieve with other tests such as X-rays. 

This technology can be used to help detect disease in its earliest stages. Conditions that may require an ultrasound include: 

  • Abnormal blood or urine test results 
  • Examination of soft tissues such as eyes, ligaments, fetus, tendons, and thyroid glands 
  • Heart conditions 

We can conduct many diagnostic tests at our in-house veterinary diagnostic laboratory in Gaithersburg to quickly and accurately identify your pet's condition.

We also collaborate with Eastern Vet Pathology and Synergy Veterinary Imaging Partners for additional diagnostic tests. CT scans, MRIs and ultrasounds are some of the many diagnostic services offered at Veterinary Referral Associates. 

Your veterinarian will recommend which test is best for your pet based on the structure to be examined and what he or she hopes to discover. 

How Can I Prepare for My Dog or Cat's CT Scan, MRI or Ultrasound Appointment?

CT scans are often done when a cat or dog is brought in for an appointment with one of our veterinary specialists. No preparation for these is required.

Depending on the area of the body to be examined, ultrasounds require different preparations. For example, particularly with abdominal ultrasounds, you may be required to withhold food and water for between 8 and 12 hours. The urinary bladder can be examined best when it is full of urine, which is why your dog or cat should not urinate for about 3 to 6 hours before the ultrasound, if possible. 

The area to be examined will likely need to be shaved so clear ultrasound images can be produced. 

Preparation instructions for an MRI may vary depending on what the vet is looking for. Their may be fasting requirements for which you'll need to withhold food for a specific number of hours. You may also need to restrict medication intake and remove any metal objects from their body, such as a collar. Following these guidelines is important so the best results can be achieved. 

The vet specialist will examine your pet and take some time to explain the CT scan, MRI or ultrasound procedure if one is required. They'll also discuss what they will be looking for. 

If a diagnostic test is scheduled ahead of time for your pet at our vet lab in Gaithersburg, you'll receive any instructions you'll need for the day of the procedure from your veterinary specialist. 

Will My Dog Or Cat Be Sedated When They Have Their Diagnostic Imaging Test?

If your dog or cat is calm, not in too much pain, and able to lay in a comfortable position while the CT scan or ultrasound is being taken, sedation will not be necessary.

On the other hand, if your dog or cat is squirmy, edgy, or in pain sedation will be recommended. Other reasons why sedation may be used during your pet's scan or ultrasound include if the dog's or cat's muscles need to be relaxed to get a clear image.

If biopsies need to be done, your pet will require a short-acting anesthetic or heavy sedative to help them relax during the ultrasound procedure, and to prevent potential complications. Your veterinary specialist will let you know if this is necessary.

For an MRI to be successful, the patient needs to remain still, so a general anesthetic will be administered to your dog or cat before their MRI scan. Vets usually recommend blood tests and X-rays be completed before diagnostic tests to be sure that your pet is healthy enough to be under general anesthetic. 

Are CT Scans, MRIs and Ultrasounds Safe For Dogs And Cats?

CT scans and ultrasounds are very safe procedures. Like an X-ray, CT scans use ionizing radiation, but at doses that are not harmful to pets.

X-rays and CTs are typically used only occasionally and generally as diagnostic tools. In some circumstances, vets will use X-ray technology to glean information about a dog's pregnancy however other forms of imaging such as ultrasound could be used in that case. Ultrasounds do not use radiation, and the sound waves are not harmful or painful to your cat or dog. 

If you're concerned about the use of X-ray or CT scanner technology and your dog's or cat's health, speak to your vet. Your veterinarian will be able to give you an understanding of the risks versus the benefits in your dog's and cat's particular case so that you can decide whether you want your dog or cat to have an X-ray or CT scan.

How Much Will My Dog or Cat's CT Scan, MRI or Ultrasound Cost?

There is a range of factors that will dictate the cost of your dog's or cat's diagnostic tests, including the size of your pet, the area being examined, whether sedation was used, the type of clinic, where your veterinary clinic and diagnostic lab are located, and more. If you are concerned about the cost of your cat or dog's diagnostic tests, ask your vet for an estimate before proceeding.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

Do you have questions about CT scans, MRIs, ultrasounds or other diagnostic imaging technologies? Contact our Gaithersburg vet specialists today.  

New Patients Welcome

Veterinary Referral Associates is accepting new patients! Our experienced vets are passionate about the health of Gaithersburg companion animals. Get in touch today to book your pet's first appointment.

Contact (301) 926-3300