Two new studies use MRI to map painful malformations in toy dog breeds

Stefano Venturi/Shutterstock.comResearchers from the University of Surrey School of Veterinary Medicine collaborated with neurologists at Fitzpatrick Referrals and Helsinki University and a geneticist from the University of Montreal on two Chiari malformation and Syringomyelia disorder studies that were published in PLOS ONE in January, according to a University of Surrey release.

The first study used a novel MRI mapping technique to study how the Chiari malformation, a skull bone deformity that changes the flow of cerebrospinal fluid and creates fluid-filled pockets (Syringomyelia) in the spinal cord, develops in the Cavalier King Charles spaniel-a breed that is predisposed to the condition.

Thanks to detailed MRI footage of the the dog's skull, brain and vertebrae, researchers were able to see how the premature fusion of bones in the skull can both compress a dog's brain and cause a dog's face to become flatter and more doll-like, depending on the fusion location.

Using a similar method, the second study discovered that the hind skull was smaller in Syringomyelia-affected Cavalier King Charles spaniels, Chihuahuas and affenpinschers, which altered how the skull lined up with adjacent bones.

The MRI footage also revealed differences among the three breeds. Chihuahuas exhibited a smaller angle between the skull base and the first and second neck vertebrae. And while affenpinshers had less space between the first and second vertebrae, Cavalier King Charles spaniels had less space between the skull base joint and the first cervical vertebrae.

“Toy dogs are increasingly popular and as such demand for these breeds is unprecedented,” says University of Surrey researcher Clare Rusbridge, BVMS, DECVN, PhD, MRCVS, RCVS. “Due to selection for rounded head shapes with short muzzles, we are seeing more and more dogs with the painful Chiari malformation and Syringomyelia disorder. The innovative mapping technique used in this study has the potential to provide a diagnostic tool for vets, helping them to quickly identify dogs suffering from these painful disorders.”