Syringomyelia in Dogs
Syringomyelia (SM) is a condition in which fluid-filled cavities (syrinxes) form within the spinal cord, most commonly associated with Chiari-like malformation in Cavalier King Charles Spaniels. The hallmark sign is “phantom scratching” — scratching at the neck or shoulder without making contact — along with neck pain and progressive neurological dysfunction.
MRI is the only way to diagnose syringomyelia. At Sage Veterinary Imaging, our 3-Tesla MRI provides the resolution needed to visualize syrinx cavities within the spinal cord, measure their size, identify the underlying Chiari-like malformation, and monitor disease progression or treatment response over time.
SVI offers advanced mri services at our centers in Round Rock, Texas; Spring, Texas; and Sandy, Utah.
Syringomyelia at a Glance
What Causes Syringomyelia?
Syringomyelia in dogs is almost always secondary to Chiari-like malformation (CM), a condition where the back of the skull is too small for the cerebellum. This overcrowding forces the cerebellum and brainstem to herniate through the foramen magnum (the opening at the skull base), obstructing the normal flow of cerebrospinal fluid (CSF).
When CSF flow is obstructed, abnormal fluid dynamics create pressure differentials that force fluid into the spinal cord, forming syrinx cavities. These syrinxes damage the spinal cord from within, disrupting pain pathways and motor function. The damage is typically most severe in the cervical (neck) region of the spinal cord.
The condition is overwhelmingly associated with Cavalier King Charles Spaniels due to selective breeding for a dome-shaped skull that is often too small to accommodate the brain. Studies suggest 70% or more of Cavaliers have some degree of SM on MRI, though not all are clinically affected.
Signs & Symptoms of Syringomyelia
Syringomyelia signs range from subtle pain behaviors to significant neurological dysfunction. Many affected dogs show signs between 6 months and 4 years of age.
How MRI Diagnoses Syringomyelia
MRI is the only imaging modality that can diagnose syringomyelia. The syrinx cavities within the spinal cord and the Chiari-like malformation at the craniocervical junction are invisible on X-rays, CT, and ultrasound.
What Our 3T MRI Reveals
Syrinx identification and measurement — MRI clearly shows fluid-filled cavities within the spinal cord as bright signal on T2-weighted images. Our radiologists measure syrinx width relative to cord diameter, which correlates with clinical severity and helps monitor progression.
Chiari-like malformation — MRI shows the degree of cerebellar herniation through the foramen magnum, the presence of dorsal compression, and any associated conditions like atlantoaxial instability.
CSF flow assessment — Advanced MRI techniques can evaluate CSF flow dynamics at the craniocervical junction, helping identify the degree of obstruction driving syrinx formation.
Serial monitoring — Repeat MRI studies track syrinx size over time, assessing whether the condition is stable, progressing, or responding to treatment (medical or surgical).
MRI vs. Other Imaging for Syringomyelia
MRI
The only way to see syrinxes and Chiari malformation. Measures syrinx size, evaluates CSF flow, and monitors progression.
CT
Shows skull shape and bone anatomy. Cannot visualize the spinal cord or syrinxes. Useful only as a surgical planning adjunct.
X-Ray
Cannot visualize the brain, spinal cord, or syrinxes. Shows only bone. Not useful for syringomyelia diagnosis.
Which Breeds Are Most at Risk?
Breeds at Highest Risk
Cavalier King Charles Spaniels are by far the most affected breed, with studies showing 70%+ have some degree of syringomyelia on MRI. Brussels Griffons (Griffon Bruxellois) are the second most commonly affected breed. King Charles Spaniels (English Toy Spaniels), Chihuahuas, and Pomeranians can also develop CM/SM. Responsible breeding programs use MRI screening to reduce SM prevalence in breeding lines.
What to Expect During a Syringomyelia MRI
MRI evaluation for syringomyelia includes imaging of both the brain (to assess the Chiari-like malformation and cerebellar herniation) and the cervical/thoracic spinal cord (to identify and measure syrinxes). The study takes approximately 60–90 minutes under general anesthesia.
Results are interpreted by a board-certified veterinary radiologist the same day. The report includes detailed measurements of syrinx size, cerebellar herniation, and any additional findings, providing your veterinarian or neurologist with the information needed to guide treatment decisions and establish a monitoring plan.
Dr. Jaime Sage, DVM, MS, DACVR
Dr. Jaime Sage is the founder of Sage Veterinary Imaging and a board-certified veterinary radiologist (DACVR) with advanced expertise in diagnostic MRI for companion animals. Dr. Sage personally interprets complex cases and works closely with referring veterinarians to ensure every imaging study delivers clear, actionable diagnostic answers.
Her published research on MRI in veterinary medicine — co-authored with Dr. Patrick Gavin, a pioneer in the field — has contributed to advancing the standard of care for pets requiring advanced diagnostic imaging.
Why Choose Sage for Syringomyelia Evaluation
Schedule a Syringomyelia MRI
If your Cavalier or other at-risk breed is showing signs of neck pain, phantom scratching, or neurological problems, MRI can confirm the diagnosis and guide treatment.
Syringomyelia FAQ
Get Answers for Your Pet
If your dog is showing signs of syringomyelia, MRI is the essential first step toward accurate diagnosis and effective pain management. Visit one of our locations to get started.