MRI is the most common diagnostic imaging tool used in both human and veterinary medicine to visualize the nervous system and is the current gold standard for imaging the nervous system in dogs and cats. MRI provides high quality images with excellent detail and resolution of the brain and spinal cord compared to other imaging tools, such as computed tomography (commonly referred to as a CAT scan).
Common examples of MRI use in animals include paralyzed dogs with disc hernaition, (figure 1 – below), brain tumors (Figure 2 – below), stroke (Figure 3 – below), and many other conditions such as rupture cranial cruciate ligament (Figure 4 – below).
MRI techniques for animals are exactly the same as those for humans. Despite aggressive marketing by some veterinary hospitals, there is no such thing as a “veterinary MRI.” The imaging technique is exactly the same whether a “human MRI” machine or a “veterinary MRI” machine is used. The only difference between people and animals receiving an MRI is that animals will not lie still when asked.
In general, it takes approximately 45 minutes to perform a MRI scan. Thus, animals must be under anesthesia for the scan. Prior to this, blood tests and X-rays often are performed to make sure that your pet is as safe an anesthetic candidate as possible.
MRI is very safe and complications associated with anesthesia are rare. The MRI is read the same day in house by a board-certified neurologist for patients with brain or spinal cord disease or within 24 hours by our board-certified radiologist for non-nervous system MRI scans.
Figure 1: Spinal MRI of a dachshund paralyzed due to disc herniation
A – arrow: Spinal MRI scan of a Dachshund paralyzed due to a large disc herniation causing compression of the spinal cord (arrow head).
- Figure 1a is a side view of the spinal cord (head is to the left)
- Figures 1b and 1c are cross-sections through the spinal cord.
- Compare the size of the spinal cord at the site of disc herniation (figure 1b) to the normal size of the spinal cord (figure 1c) below the disc herniation.[/accordion-content]
Figure 2: MRI of the brain of a cat with a history of seizures, lethargy and weakness.
MRI of the brain of a cat with a history of seizures, lethargy, and weakness. The MRI shows a large meningioma, the most common brain tumor seen in cats. Despite the large size of the tumor, the cat did very well following surgery. It lived another three years after the tumor was surgically removed.
This cat died of unrelated causes, but until then, quality of life remained very good.
Figure 3: MRI of the brain of a Greyhound following a sudden onset of a head tilt, incoordination and a high-stepping gait on one side.
MRI of the brain of a Greyhound following a sudden onset of a head tilt, incoordination and a high-stepping gait on one side. The MRI shows a cerebellar infarct (stroke) in the cerebellum. The dog fully recovered within 1 week.
Figure 4: MRI of the stifle (knee) of a dog with a chronic lameness in right rear leg.
MRI of the stifle (knee) of a dog with chronic lameness in the right rear leg. The surgeon was suspicious that the dog had a ruptured cranial cruciate ligament (arrow), the ligament that athletes blow out in their knee. The orthopedic exam was not definitive due to the soft tissue thickening around the knee.
MRI demonstrated that the ligament had indeed been torn and the dog was taken to surgery for repair. The caudal cruciate ligament is intact, although the end is not visible in this image.Back to Top