Dr. Sue Schaefer, UW Veterinary Care orthopedic surgeon, was very frustrated with the tools available to her for diagnosing shoulder problems in dogs. So, she began her own research on the application of MRI technology to muscular skeletal anatomy and to orthopedic problems in dogs.
“Many of our clients come in and say they’ve had an MRI on their knee or on their shoulder and they want the same thing done for their animal because they understand that it is a very useful diagnostic tool,” Schaefer said. “But we didn’t have a baseline for being able to look at the dog shoulder. I could do an MRI of a dog that has lameness in its forelimb and has pain in its shoulder, but I wouldn’t know what I was looking at.”
Since no one had written an anatomy guide to what a normal dog shoulder should look like under MRI, Schaefer decided to do just that. She began her research several years ago by using MRI to compare normal joints to abnormal joints and is now using this information for what she calls the “Dog Shoulder Atlas.”
“You have to have a baseline, you have to have a guidebook,” she said. “If we’re doing an MRI and we are trying to look for torn ligaments or torn cartilage we need to know what normal looks like and we need to know where we would find it on the MRI—where in the joint I should find one specific tendon and another ligament, where’s the normal position, what’s the normal size, those kinds of things.”
Schaefer began her research by using cadaver joints from dogs who died from other unrelated illnesses. She used these joints in her “normal” group and evaluated them with MRI to determine “normal.” From this, she created scans of different sections and different views and angles of those sections to put together her atlas of normal joints.
“We were able to match the anatomy perfectly with what we see on the MRI so I can now go back to the MRI and say ‘oh I know this is the bicep tendon, I know that this is the supraspinatus tendon, I know this is the humerus, because here’s my guide’,” Schaefer said. She would then compare the scans from her “normal” group to actual patients in order to determine the nature and location of the problem.
“This is really a foundation,” said Schaefer. “We undertook a clinical trial performing MRIs on dogs in our clinic with shoulder problems. We then confirmed [through] surgery that the MRI showed the same changes seen at surgery. We were able to demonstrate that MRI is a useful tool. Through clinical research we were able to validate its application to diagnosing shoulder injuries in dogs. We need to develop an atlas for all of the joints in the dog, but we’ve started with the shoulder. I wanted to start here because it is a very challenging joint.”
Now Dr. Schaefer and others can use this atlas to better diagnose patients who have shoulder problems and to prescribe the best treatment options. “The more we learn about the shoulder, the more we understand how complex it is, the better we are at diagnosing very specific tendon and ligament problems. If we get better diagnostic information, then we can figure out better ways to treat the animals. It improves our therapeutics.”
Schaefer isn’t finished yet. Her next area of interest is the “Dog Hip Atlas!”