If your dog has Degenerative Myelopathy, you’re going to want to pay close attention to this study at Cornell University. Dr. Philippa J. Johnson is trying to determine if a cutting-edge MRI technique, called diffusion tensor imaging, is able to identify early spinal cord lesions that are caused by degenerative myelopathy. In plain English, this medical jargon means there could soon be a reliable advanced imaging procedure to diagnose degenerative myelopathy. And if that happens, a whole new world of treatment for DM dogs could become a reality.
I had the privilege of interviewing Philippa Johnson, BVSc, MSc, CertVDI, DipECVDI, MRCVS about her study and what it could potentially mean to sick dogs. She also shared how pet owners can enroll their dog in the clinical trial. That information is at the end of this story.
Before we start, here is a short explanation about DM
Degenerative myelopathy is a progressive neurologic disease caused by a degeneration of the spinal cord. It most often strikes dogs between the ages of 8-14. The symptoms begin with a loss of coordination and weakness in the hind legs. That progresses to paralysis in the back legs. Eventually the paralysis moves to the front limbs and respiratory system. Dogs typically pass away after 2-3 years, although some dogs live up to 5 years.
The disease is seen in a number of large breed dogs like German shepherds and Golden retrievers and a few smaller breeds like Shetland sheepdogs and Corgis.
Existing diagnosis methods
Dogs currently receive a diagnosis of DM based on their symptoms and by omission, which means other illnesses have been ruled out. There is no definitive test to diagnose DM.
The Orthopedic Foundation for Animals (OFA) has a DNA test, but it cannot diagnose degenerative myelopathy. It is limited to telling pet owners if their dog is a carrier or at-risk for developing the disease. At this time, the only way to positively confirm degenerative myelopathy is through a necropsy (post mortem exam).
Dogs suspected of having DM are routinely sent for a MRI, but like the DNA test it can’t confirm the disease. The test used to rule out other problems with the spine. The standard MRI is not able to pick up the spinal lesions that are caused by degenerative myelopathy.
Help from ALS patients
DM is very similar to a disease in humans called ALS (Amyotrophic lateral sclerosis) or Lou Gehrig’s disease. For years, the two diseases have been studied in conjunction with each other. Not long ago, a clinical trial for ALS patients discovered that microscopic changes in the spinal cord could be seen when the advanced MRI technique of diffusion tensor imaging was applied. Diffusion tensor imaging uses the motion of water molecules to detect changes.
Dr. Johnson was intrigued by the results of the ALS study and put together a similar clinical trial for dogs. The goal is to determine whether diffusion tensor imaging can detect early spine lesions in dogs with symptoms of DM. If so, it would be the first way to confirm the diagnosis degenerative myelopathy in a living dog.
The Morris Animal Foundation has granted funding for the advanced imaging study for two years.
Here is what Dr. Johnson had to say about the study and her hope for the future of DM dogs:
Q: Your specialty is in veterinary radiology. What is your background in the field?
I’m a veterinarian who trained in spine and brain imaging and developed an interest for research in the area. That led me to getting a master’s degree in human neuroimaging. Their programs are more advanced. I wanted to take the knowledge I learned and improve the diagnosis for dogs with degenerative myelopathy. I hope that will lead to understanding the disease better.
Q: Please explain an overview of the study.
The problem we are addressing is that the standard MRI doesn’t see the lesions in the spine that form with canine degenerative myelopathy. And the DNA test cannot predict onset of clinical signs. Some dogs who receive test results that say they are “at risk” to develop DM, never show signs of the disease. The two current tests leave us with more questions than answers.
Diffusion tensor imaging for ALS patients has proven it can detect lesions in the spine. It confirms the condition and tells patients how far their disease has progressed. Our study will use the identical imaging technique with the goal of getting similar results in dogs.
Q: There is no cure for degenerative myelopathy. How will the ability to see spinal lesions help these dogs?
We will be able to tell owners how bad the lesions are and what stage of the disease their dog has. If they are in the early stages, we can advise owners to enroll their dog in a physical therapy program or other rehabilitation therapy.
Dogs will also be helped because veterinarians will have a tangible method for monitoring the results of new treatments. And we will be able to monitor dogs at risk, but not yet sick.
Q: If your theory is correct, will diffusion tensor imaging be readily available to the average pet owner with a sick dog?
Most universities are getting tensor advanced imaging. If we prove it to be useful for diagnosing pets, more private veterinary hospitals will add them. Diffusion tensor imaging is one of the fastest growing fields. It could potentially be used in the diagnosis of epilepsy and brain tumors in animals.
You’ll also see more of them as hospitals upgrade their MRI machines, which happens approximately every 10 years. I think diffusion tensor imaging will become commonplace.
Q: Will an advanced MRI cost more?
It shouldn’t be more expensive because it will be part of a hospital’s MRI machine. It’s not an added feature to an existing piece of equipment.
Q: Do you need dogs for the study?
Yes. We want to have a total of 30 dogs; 15 normal, healthy dogs and 15 dogs that show clinical signs of degenerative myelopathy. The normal dogs must be at least 8-years-old.
Dogs enrolled in the study will only need to come to Cornell University one time. They will receive an exam, blood work and undergo the advanced MRI procedure while under anesthesia.
Pet owners must also agree to another key part of the study. That will be a post mortem exam of their dog by the Cornell University pathologist. The university will work with your personal veterinarian to coordinate transportation after your dog has passed.
Q: Do the dogs need to be purebreds?
No, dogs in the study do not have to be purebreds. We’ve had a Corgi, several German shepherds, Boxers and 4 mixed breed dogs take part. We’ve also had people enroll their dogs even if they don’t live in New York. One pet owner traveled from Michigan. She brought her normal, healthy dog and her dog with DM symptoms. We have arranged for MSU College of Veterinary Medicine to do the post mortem exam so the woman doesn’t have to make a second trip here. We are trying to be very flexible.
How to enroll your dog in the study
Dr. Johnson is in need of 5 additional dogs who show clinical signs of DM and 10 normal dogs without signs of neurological disease. Dr. Johnson explained that she is having a harder time enrolling healthy dogs. Some of the normal dogs are housemates of the sick dogs.
If you would like to learn more about enrolling your dog, please email the clinical trials coordinator at: [email protected] Or click here to read the clinical trial requirements.
This is an extremely important clinical study for those of us with paralyzed dogs. Please share this story with dog owners who you think might be interested in helping.