Magnetic Resonance Imaging (MRI) in dogs
What is it for?
How is it done?
What are the risks?
Recover tips
When to worry
Magnetic Resonance Imaging (MRI) in dogs
Magnetic Resonance Imaging (MRI) is an advanced diagnostic tool that allows veterinarians to examine a pet’s internal anatomy in detail. MRI scans are commonly used in dogs, cats, and other small animals, and are particularly useful for evaluating soft tissues, including the brain, intervertebral discs and spinal cord. MRI is considered a very safe and valuable method for clinical diagnosis.
An MRI machine uses a powerful magnet to send gentle magnetic waves through the body, causing some molecules to emit a brief radio wave. These signals can be transformed by a computer into detailed images of the structures inside the body.
What is an MRI for?
An MRI is the most useful imaging tool for evaluating the nervous system and getting an accurate diagnosis for certain neurological conditions. Conditions that it can help diagnose include intervertebral disc disease, brain disease, inner ear problems and also some musculoskeletal issues like cruciate ligament disease.
It provides detailed information about the spinal cord. This helps determine where and how much the spinal cord is being compressed, as well as the severity and extent of nerve damage.
It also shows how much disc material has escaped and entered the space near the spinal cord, which is essential for planning surgery.
The MRI can also be used to evaluate the damaged disc and assess the need for preventive measures (disc fenestration).
MRI is uniquely useful for diagnosing brain problems, often being capable of identifying abnormal brain areas in a lot of detail, be it due to a tumour, bleeding, inflammation or degeneration.
This ability to evaluate soft tissues is also used to diagnose disease in the complex structures of the inner ear.
The complex structures inside major joints are also best looked at with MRI. Ligaments and other soft structures inside the joints can be seen in great detail, unlike other methods.
How is an MRI done in dogs?
MRIs are very safe and non-invasive procedures, but they can be time-consuming. MRI scans require the patient to remain completely still inside a confined space that produces loud noises. Because even small movements can blur or distort the images, dogs are placed under general anaesthesia to ensure they remain motionless throughout the procedure and to minimise stress while inside the machine.
Your dog will be lying on their back on the MRI table. They will be constantly monitored with specialised equipment during the procedure.
The machine goes through a series of steps, in which it briefly creates a magnetic field and measures how this affects the dog’s body.
To reduce the anaesthetic time and improve the quality of the images, the MRI focuses on the affected area of the body. Looking at different structures requires repeating the whole procedure and could yield equivocal results.
What are the risks of doing an MRI in dogs?
Overall, the procedure is considered very safe and is usually well tolerated by patients.
MRI machines use very powerful magnets, but these don’t cause any damage or permanent changes to humans or animals. The only risk from the magnet is that it can displace certain types of metal implants, if your dog has any. Equally, metallic implants distort the image that we acquire and could make it non-diagnostic. Most modern surgical plates and materials are MRI-safe. If your dog has previously had major surgery with implants (for example, to repair a broken bone or ligament), be sure to discuss this with your vet.
General anaesthesia always carries a small risk, and this depends on the dog’s overall health. Every dog will have a thorough examination and risk assessment, and your vet will discuss any concerns with you. IVDE does not increase anaesthetic risk. If there are no other illnesses present, the chances of complications from the MRI are very low.
Recovery tips after an MRI
After the MRI scan, your pet will need a short period to recover from the anaesthesia. During this time, the veterinary team will monitor them closely to make sure they wake up safely and comfortably. Once your pet is stable, they will usually be able to go home.
Your dog will be drowsy or wobbly for a few hours or sometimes longer. Keep them in a quiet and comfortable environment.
Let them rest and make sure they have easy access to water and food. They may also need help staying warm; a cosy blanket may help.
Keep an eye on them to make sure they are recovering well.
When to worry about your dog after an MRI
Speak to a vet straight away if your pet is:
