Syringomyelia (SM) and the
Cavalier King Charles Spaniel

• IN SHORT
• IN DEPTH
• CM - OH - COMS
• What SM Is
• Symptoms
• Diagnosis
• - MRIs
• - CTs
• - thermography
• - ultrasound
• - BAER
• MRI Clinics
• Progression
• Treatment
• - drugs
• - alternative care
• - surgery
• - soundwave therapy
• Current Research
• Seminars
• Breeders' Responsibilities
• What You Can Do
• Related Links
• Veterinary Resources

IN SHORT:

Syringomyelia (SM) is an extremely serious condition in which fluid-filled cavities develop within the spinal cord near the brain.  It is also known as "neck scratcher's disease", because one of its common signs is scratching in the air near the neck.

The back half of the Cavalier King Charles spaniel’s skull typically may be too small to accommodate all of the brain’s cerebellum, which may also be too large, and so it squeezes through the foramen magnum – the hole at the back of the skull – partially blocking the flow of cerebrospinal fluid (CSF) down the spinal cord. The variable pressure created by the abnormal flow of CSF is believed to create the SM cavities – called syrinx – in the spinal cord.

SM is rare in most breeds but has become very widespread in Cavalier King Charles spaniels. The number of diagnosed cases in Cavaliers has increased dramatically since 2000. Researchers estimate that up to 95% of CKCSs have Chiari-like malformation (CM or CLM) – also known as caudal occipital malformation syndrome (COMS) or occipital hypoplasia (OH), the skull bone malformation believed to be at least part of the  cause of syringomyelia – and that as many as 50% of Cavaliers have SM. The severity and extent of syringomyelia also appear to get worse in each succeeding generation of Cavaliers. It is worldwide in scope and not limited to any country, breeding line, or kennel, and experts report that it is believed to be inherited in the Cavalier.  More... 

Symptoms

SM seldom can be detected in young puppies, as symptoms of it usually are not evident before the age of six months or years later.

Pain is the most important clinical sign of the disorder.  Symptoms may vary widely among different dogs, but the earliest sign often is that the dog feels a hypersensitivity in its neck area, causing an uncontrollable urge to scratch at its neck and shoulders. Then usually follows severe pain around its head, neck, and shoulders, causing it yelp or scream. As the disease progresses, it destroys portions of the Cavalier's spinal cord, and is so painful that the affected dog may contort its neck and even sleep and eat only with its head held high. The dog's legs may become progressively weaker, so that walking becomes increasingly difficult.  Some dogs deteriorate to the point of paralysis. More...

Diagnosis

The only accurate way of diagnosing the disease is through the use of magnetic resonance imaging (MRI) scanning, an extremely costly procedure.  The MRI allows the veterinary neurologist to study the spine for the presence of  any abnormality which might obstruct the flow of the cerebrospinal fluid.   Accurate MRI results require that the dog be anesthetized.  Clinic charges for MRI examinations of canines have been known to vary from a rare discounted rate of $900.00 to over $2,000.00.

The names and locations of veterinary neurologists who are board certified by the American College of Veterinary Internal Medicine (ACVIM) are on our Neurologists webpage.

Another disorder common to Cavaliers and with symptoms similar to SM is Primary Secretory Otitis Media (PSOM), which is a highly viscous mucus plug which fills the middle ear and causes the tympanic membrane to bulge.  Because the pain and other sensations in the head and neck areas, resulting from PSOM, are so similar to symptoms due to SM, the possibility that the Cavalier has PSOM and not SM should be determined before diagnosing SM.  More...

Treatment

Treatment options for SM are very limited.  Before the disease progresses to its severe form, the use of cortisteroids, such as prednisolone, or non-steroidal anti-inflammatory drugs (NSAIDs, such as Rimadyl and Metacam) may relieve the symptoms but not the deterioration. Cortisteroids have serious side effects, such as weight, gait, and skin changes, and harmful suppression of the immune system.  Long term use of these drugs is not advised.

Anticonvulsants, such as gabapentin (Neurontin), have been successful in some more severe cases, but they may be very expensive.  Oral opioids (pethidine or methadone) are alternatives.  Methylsulfonylmethane (MSM) is recommended by some veterinary neurologists as a dietary supplement.

Drugs which reduce the production of cerebrospinal fluid, including proton pump inhibitors such as omeprazole (Prilosec), and the diuretic, furosemide (Lasix, Diuride, Frudix, Frusemide) and spironolactone (Aldactone), may be useful, but clinical data on their use and effectiveness is lacking.  Carbonic anhydrase inhibitors, such as acetazolamide (Diamox) also serve to decrease the flow of cerebrospinal fluid, but their adverse side effects of abdominal pain, lethargy, and weakness limit long term use.

Surgery to allow the cerebrospinal fluid to flow normally may be necessary to reduce the pain and deterioration.  However, such surgeries are technically difficult and should be performed only by specialists.  In some cases a shunt is installed.  Although surgery often is successful, it is very expensive, and many dogs either have a recurrence of the disease or still show signs of pain and scratching.  The most frequent reason for recurrence reportedly is the development of  post-operative scar tissue. At least one neurologist has been inserting titanium mesh, in an effort to prevent such scar tissue from building up.  More...

Breeders' Responsibilities

SM has a tendency to be more severe in each subsequent generation, and with an earlier onset.  Breeders should follow the SM Breeding Protocol.  The aim of the breeding protocol is to reduce the incidence of symptomatic syringomyelia in the Cavalier breed, and not to create litters of puppies guaranteed not to have SM.  The chance of producing an affected dog cannot be predicted without knowing the inheritance.

What You Can Do

4Donate by buying For the love of Ollie.

4Participate in the Syringomyelia Cavalier Collection Scheme. Read about it here.

4Donate funds to Cavalier SM DNA research; payee "Syringomyelia DNA Research", address: Stone Lion Veterinary Hospital, Goddard Veterinary Group, 41 High Street Wimbledon Common London SW19 5AU, email CRusbridge@goddardvetgroup.co.uk, telephone: 020 8946 4228, fax: 020 8944 0871.  Read about it here.

4Send MRI scans of Cavaliers 5 years old or older and which do not have SM, along with MRIs of those dogs' family members, to Dr. Clare Rusbridge at neuro.vet@btinternet.com Read about it here.

4Contact Sheena Stevens in Devon, UK, telephone 01884 821080, email Kilnshena@hotmail.com, about sending aborted Cavalier fetuses and deceased young puppies (that have died for any reason) to Dr. Imelda McGonnell at The Royal Veterinary College for research. Read about it here.

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IN DEPTH:

Syringomyelia (SM -- also known as syrinx and hydromyelia, and occasionally mis-identified as Arnold Chiari malformation) is a condition of the development of fluid-filled cavities in the spinal cord, which is believed by researchers to be due to abnormal flow of cerebrospinal fluid (CSF) between the brain and the spinal cord through the foramen magnum at the base of the skull.  It more technically is described as syringomyelia secondary to Chiari-like malformation (CM or CLM).  CM also is referred to as occipital hypoplasia (OH) or  caudal occipital malformation syndrome (COMS).

SM is rare in most breeds but has become very widespread in Cavalier King Charles spaniels.  Some researchers estimate that as many as 95% of CKCSs have Chiari-like malformation (CM or CLM), the skull bone malformation believed to be a part of the cause of syringomyelia, and that up to 50% of Cavaliers have SM. It is worldwide in scope and not limited to any country, breeding line, or kennel, and experts report that it is believed to be inherited in the Cavalier King Charles spaniel. CM is so widespread in the Cavalier that it may be an inherent part of the CKCS's breed standard.

The severity and extent of syringomyelia also appear to get worse in each succeeding generation of Cavaliers.  Other breeds known to be affected to a lesser extent include the Boston terrier, Brussels Griffon (Griffon Bruxellois), bull terrier, Chihuahua, King Charles spaniel (the English toy spaniel), Maltese terrier, Pomeranian, toy poodle, and the Yorkshire terrier.

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Chiari-like malformation (CM or CLM) -- Occipital hypoplasia (OH) -- Caudal occipital malformation syndrome (COMS)

These three terms have been used to identify the malformation believed to cause syringomyelia.  Although they technically mean different things, they often are used interchangeably.  Some neurologists prefer one term over the others. However, researchers meeting at the International Conference on Syringomyelia at the Royal Veterinary College in London in November 2006 agreed upon the use of Chiari-like malformation (CM or CLM) to describe the malformation found in the Cavalier and to a lesser extent in a few other breeds.

4Chiari-like malformation (CM or CLM): The foramen magnum is a hole in the back of the skull, leading to the spinal cord. In the Cavalier breed, the back half of the skull is smaller than the typical toy dog breed. This condition is called Chiari-like malformation, named after a similar condition in humans, discovered by Dr. Hans Chiari. Chiari-like malformation is defined as "decreased caudal fossa volume with caudal descent of the cerebellum, and often the brainstem, into or though the foramen magnum."  See Karen Kennedy's* Understanding Canine Chiari Malformation and Syrningomyelia for diagrams of the occipital bone and foramen magnum.

There is not yet a consensus among veterinary investigators as to how to measure the Cavalier's occipital bone to determine what should be the shape of the cerebellum within a "normal" CKCS's occipital bone.  Dr. Clare Rusbridge,  BVMS, MRCVS, PhD, DipECVN, of the Stone Lion Veterinary Centre in London, England, a leading investigator into SM, describes the three "classic features" of occipital malformation as: (1) loss of the normal round shape of the cerebellum, which can appear to be indented by the occipital bone; (2) displacement of the cerebellum into and through the foramen magnum, i.e. herniation; and (3) kinking of the medulla.

In a 2006 study conducted by Dr. Natasha J. Olby and Dr. Sofia Cerda-Gonzalez, both board certified veterinary neurologists, and others at North Carolina State University's College of Veterinary Medicine's Department of Clinical Sciences and the IAMS Pet Imaging Center in Raleigh, NC., they have concluded that the incidence of caudal fossa and cervical spinal abnormalities is high in Cavaliers, and that the pathogenesis of syringomyelia is multifactorial rather than due to a single malformation.

In a 2009 Scottish study led by Dr. Jacques Penderis, of 70 Cavaliers and 80 dogs of other breeds, the researchers found that "all [of the] CKCSs had abnormalities in occipital bone shape. ... CKCSs had a shallower caudal cranial fossa and abnormalities of the occipital bone, compared with those of mesaticephalic dogs. These changes were more severe in CKCSs with syringomyelia."

In a 2009 German study of 40 Cavaliers and 25 dogs of other brachycephalic breeds, the researchers concluded: "Results of this study suggested that descent of the cerebellum into the foramen magnum and the presence of syringohydromyelia in CKCSs are not necessarily associated with a volume reduction in the CF of the skull."

In a 2009 UK study comparing the cerebral cranium volumes of the CKCS with those of other small breeds and the Labrador retriever, Hannah Cross and Drs. Rusbridge and Rodolfo Cappello found that Cavaliers do not have a proportionately smaller caudal fossa compared to other small breeds, but that the CKCS's brain is comparatively large.

In that 2009 UK study, the researchers found:

"When compared with Labradors, CKCS had proportionately the same volume of parenchyma in their caudal fossa, hence there is a mismatch of volumes with too much parenchyma in a too small caudal fossa causing overcrowding. ... Other small breeds of dogs had a proportionately smaller volume of parenchyma in their caudal fossa which can explain why, despite having a similar sized caudal fossa to CKCS, they do not experience overcrowding. It is hypothesised that through the miniaturisation process of other small dogs, both the cranium and brain are proportionately smaller but in CKCS only the cranium has reduced in volume, hence why there is a higher incidence of CM in CKCS than other small breeds.

"Cavalier King Charles spaniels also had a greater percentage of their cranial fossa filled with parenchyma (cranial fossa parenchyma percentage) compared with small breeds and Labradors which had a similar percentage. Overcrowding in CKCS might therefore occur due to a mismatch in volumes in both the caudal fossa and cranial fossa of the skull, suggesting the cranial fossa is also involved in the pathophysiology of CM."

As noted above, the current definition of "Chiari-like malformation" is "decreased caudal fossa volume with caudal descent of the cerebellum, and often the brainstem, into or though the foramen magnum." However, based upon these 2009 studies of brain size, "caudal fossa volume" may not the problem. Instead, the oversized cerebellar parenchyma may be the culprit. or a combination of the two.

If the 2009 German and UK studies are on the right track, then we may have to either re-define "Chiari-like malformation" or use another term to describe the disorder, since the "malformation" is not of the caudal fossa, but of the cerebellar parenchyma. A re-definition could be "increased cerebellar parenchyma volume with caudal descent of the cerebellum, and often the brainstem, into or though the foramen magnum."

It has not been conclusively established that CM is, by itself, the cause of SM.  While CM is very widespread in the Cavalier breed, and CM logically leads to syringomyelia, the apparent severity of CM in the CKCS does not always accurately predict the presence or future presence of SM in the dog.  Ongoing research into genetic correlations between CM and SM seeks to determine whether different genes may control the expression of SM and CM.  If so, it may be possible to select breeding stock which has been diagnosed to have CM but may not be expected to produce offspring with SM genes.

4Occipital hypoplasia (OH) has been used to describe the displacement of the cerebellum into the area of the foramen magnum and a kinking of the medulla and an indentation of the cerebellum.  "Hypoplasia" is a medical term defined as underdevelopment or incomplete development, and so, "occipital hypoplasia" in this instance means an underdeveloped or incompletely developed occipital bone, which is part of the back of the skull. However, at the November 2006 London conference, this term was rejected because there is no proof yet that the condition is related to a hypoplastic occipital bone.  The actual disorder is believed to be caused either by an unusually small occipital bone or a confining membrane within the occipital bone, resulting in the cavity in the skull containing the cerebellum to be too small to fully contain it, leading to overcrowding of the caudal fossa and obstruction of the neural structures, including the incomplete closure or development of the neural tube through which flows the cerebrospinal fluid (CSF).

In a January 2009 article, Drs. Sofia Cerda-Gonzalez, Natasha J. Olby, Susan McCullough, Anthony P. Pease, Richard Broadstone, and Jason A. Osborne concluded that: "While several factors are associated with neurologic signs [of SM], occipital hypoplasia appears to be the most important factor."

Occipital hypoplasia is to be distinguished from occipital dysplasia, which is an incomplete ossification of the supraoccipital bone, causing a widening of the foramen magnum. The more brachycephalic is the shape of  the dog's skull, the more likely there will be occipital dysplasia.  The Cavalier is a brachycephalic breed, and therefore a combination of both occipital hypoplasia and occipital dysplasia can occur in the CKCS.

In a 2008 German study, the researchers recommend that Cavaliers be screened for both occipital hypoplasia and occipital dysplasia.

4Caudal occipital malformation syndrome (COMS), had been used, particularly by some specialists in the United States, to describe the disorder. However, at the November 2006 London conference, the term COMS also was rejected because there is no proof yet that the condition is related to a malformed occipital bone.

Because prior to the November 2006 London conference, CM and OH and COMS all were used to describe the same malformation, they all are used interchangeably in this article.  See Karen Kennedy's* Understanding Canine Chiari Malformation and Syrningomyelia for scans of the occipital bone and foramen magnum, comparing "normal", mild Chiari" and "severe Chiari" dogs.

*Karen Kennedy, RTMR, MappSc, is a magnetic resonance imaging specialist with The London Health Sciences Centre, London, Ontario, Canada.

4A possible cause of CM? In their 2009 report comparing the cerebral cranium volumes of the CKCS with those of other small breeds and the Labrador retriever, Hannah Cross and Drs. Rusbridge and Cappello conclude:

"The results support mesoderm* insufficiency or craniosynostosis* as the pathogenesis of Chiari-like malformation (CM) in CKCS. It presents evidence for overcrowding of the caudal fossa due to a mismatch of brain parenchyma and fossa volumes as to why CKCS and not other small dogs are affected."

*The mesoderm is the middle of the three primary germ cell layers -- the others being ectoderm and endoderm -- in the early stage of an embryo. The mesoderm is responsible for developing various tissues and structures, such as bone, muscle, connective tissue, and the middle layer of the skin. Mesoderm insufficiency during embryology may cause insufficient scope for the mesoderm and ectoderm layers to develop.  Craniosynostosis is the premature closure of the skull's growth plate.

This suggests both a possible genetic cause of CM, as well as evidence that the Cavalier's caudal fossa is too small and that its brain is too large, hence the "mismatch".

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What SM is

Syringomyelia (SM) is defined as "a condition that results in the development of fluid-containing cavities within the parenchyma of the spinal cord. as a consequence of abnormal cerebrospinal fluid movement." (November 2006 International Conference on Syringomyelia).

Cerebrospinal fluid normally flows back and forth between the brain and spinal cord with each heart beat.  As the heart pumps blood to the brain, the CSF flows from the brain through the hole called the foramen magnum to the spinal cord, to accommodate the increased volume of incoming blood.

Syringomyelia results when the cerebrospinal fluid is prevented from circulating normally between the brain and spinal cord, due to a narrowing or blockage of the CSF flow at the foramen magnum, thereby forcing the CSF at a higher than normal pressure into the spinal cord.  The pressure difference causes the spinal cord to distend or pull apart, creating a cavity called a syrinx, and squeezing fluid from blood vessels into the cavity.  Technically, hydromyelia is a dilatation of the central canal within the spinal cord, and syringomyelia is the cavitation of the spinal cord parenchyma.  Combined, they are referred to either as syringohydromyelia (SHM) or hydrosyringomyelia.  The disease is referred to generally as syringomyelia and SM herein.  This condition is similar, but not identical, to Arnold Chiari Type I Syndrome in humans.

(Note: There are other forms of syringomyelia in canines: (a) spinal dysraphism or spinal dysplasia, a genetic disorder in which puppies normally under the age of three months display a bunny hopping gait and wide-based stance and scoliosis, due to the spinal cord not developing forming completely in the womb; and (b) SM caused by tumors, cysts, or trauma; and (c) possible SM-like neurological symptoms due to Chiari-like malformation in brachycephalic breeds.  None are discussed here.)

Syringomyelia is an extremely serious, progressively worsening spinal disease which is rare in most breeds but is becoming very widespread in Cavalier King Charles Spaniels of all bloodlines.  In May 2005, Dr. Rusbridge and Susan P. (Penny) Knowler, BSc (Hons), who have been studying the disease in several hundreds of Cavaliers, reported that a conservative estimate is that at least 50% of Cavalier King Charles Spaniels have a degree of Chiari-like malformation, although not all are so severely affected as to have syringomyelia.

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Symptoms

The number of diagnosed cases in Cavaliers has increased dramatically since 2000. SM and CM very seldom can be detected in young puppies, as symptoms usually are not evident before the age of six months or even many years later. There is no way to know in advance of the symptoms whether a dog is normal or is a syringomyelia carrier which does not develop the disease but can pass it on to its offspring.

The condition causes damage to the spinal cord and usually results in symptoms of hypersensitivity, intense pain, and leg dysfunction. The primary symptoms may vary widely, and in some cases, a Cavalier may have SM without displaying any outward symptoms at all.  It also is possible that a dog with Chiari-like malformation (CM) does not have syringomyelia (the syrinx in the spinal cord), but still may have symptoms of SM due to the CM obstructing the flow of cerebrospinal fluid (CSF).

Symptoms may vary widely among different dogs, but the earliest sign often is that the dog feels a sensitivity in its neck area, causing an uncontrollable urge to scratch at its neck and shoulders excessively, particularly when walking or during other forms of exercise.  This is due to an increase in the pressure of the flow of cerebrospinal fluid through the central canal from the brain down the spinal column, causing the central canal to expand and press against the nerves of the spinal column and creating the needle-like tingling which prompts the dog to scratch.

As the disorder progresses, there usually follows increasingly severe pain around the dog's head, neck, and shoulders, causing it yelp or scream. It is believed to be a neuropathic pain, probably due to disordered neural processing in the damaged dorsal horn. As the disease destroys portions of the Cavalier's spinal cord, the dog may experience so much pain that it may contort its neck and may even sleep and eat only with its head held high.  The dog may develop scoliosis, as a result.  There may also be progressive weakness in the legs, so that walking becomes increasingly difficult. Some dogs deteriorate to the point of paralysis.

In a June 2007 study of 55 Cavaliers, the researchers reported that the wider the syrinx, the stronger the predictor of pain, scratching behavior and scoliosis in dogs with syringomyelia. They stated: "Both pain and syrinx size were positively correlated with syrinxes located in the dorsal half of the spinal cord."  They also concluded that such pain is likely to be neuropathic pain, resulting from disordered neural processing in the damaged dorsal horn.

Syringomyelia can be very deceptive because some symptoms (which may include paw licking, head shaking, head rubbing, circular walking, fly biting, and reluctance to defecate) are common behaviors for many unaffected dogs. One distinction is that dogs suffering from SM engage in these patterns excessively and seemingly compulsively. So, other causes of the dog's symptoms need to be considered and should be ruled out before concluding that SM is the cause. For example, if a syrinx develops in a lower area of the spine, such as the lumbar region, the dog may scoot excessively, even to the extent of rubbing the anal area raw. However, scooting is a common symptom of other disorders, or even of no particular disorder at all.

Another disorder common to Cavaliers and with symptoms similar to SM is Primary Secretory Otitis Media (PSOM), which is a highly viscous mucus plug which fills the middle ear and causes the tympanic membrane to bulge.  Because the pain and other sensations in the head and neck areas, resulting from PSOM, are so similar to symptoms due to SM, the possibility that the Cavalier has PSOM and not SM should be determined before diagnosing SM.

In a brief July 2009 article, UK researchers Dr. Richard J Piercy and Gemma Walmsley disclosed that they had identified a genetic form of muscular dystrophy in the Cavalier, with symptoms (weakness and exercise intolerance) similar to some of those of SM.  However, these other symptoms of this muscular dystrophy may clearly distinguish it from SM: muscle atrophy, difficulty swallowing, and an enlarged tongue.  Also, the researchers have found that only males are affected by this form of muscular dystrophy, and the females are only carriers of the mutation.

Dr. Rusbridge has a website, veterinary-neurologist.co.uk, which discusses SM extensively, as well as other neurological disorders which she has researched.  Her doctoral thesis, a 200+ page book (right), Chiari-like Malformation and Syringomyelia in the Cavalier King Charles Spaniel, also is available online.

An excellent review of the various symptoms displayed by dogs affected with syringomyelia may be found on the SM.CavalierTalk.com website, prepared by Karlin Lillington of Dublin, Ireland.  Her website includes videos of SM-affected dogs.  Other videos are available under Related Links below.  Also, see flycatcher's syndrome for a description of another disorder prevalent in CKCSs and which has identical symptoms to the fly biting of some SM/CM-affected dogs.

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Diagnosis

-- magnetic resonance imaging (MRI)

The only accurate way of diagnosing the disease is through the use of magnetic resonance imaging (MRI) scanning.  Clinic charges for MRI examinations of canines have been known to vary from $400.00 to over $2,000.00.   Accurate MRI results require that usually the dog be anesthetized.  In view of the high cost of MRI scans, the examining veterinary specialist usually will attempt to rule out other causes of the symptoms first. Veterinarians who perform MRIs of should consider following this MRI Screening Protocol devised by Dr. Rusbridge.

The MRI allows the veterinary neurologist or neurosurgeon to study the skull and spine for the presence of  any abnormality which might obstruct the flow of the cerebrospinal fluid.  When examined by MRI, the syringomyelia appears as a tubular cavity of fluid, called a syrinx, within the spinal cord. In severe cases, the syrinx is so wide that only a thin rim of the spinal cord is visible.  An MRI scan of a dog without any syrinxes at all still may show that the dog has Chiari-like malformation.

The MRI scan of a Cavalier at the right shows the occipital malformation, with the cerebellum being squeezed out of the occipital bone and into the area of the foramen magnum (red-outlined area).  It also shows pockets of white cerebrospinal fluid in the spinal cord (yellow-outlined area).  See Karen Kennedy's Basic Canine NeuroAnatomy and MRI Imaging Planes, for further information about MRI scans.

In a study conducted by Dr. Rusbridge and Ms. Knowler, in a sample of seventy "unaffected” Cavaliers from Europe and North America, which were MRI-scanned only for breeding purposes, 70% of them had syringomyelia, 17% were "at risk", meaning were young dogs with Chiari-like malformation but no syringomyelia yet, and only 13% were "clear" of both the malformation and SM.

-- computed tomography (CT)

Computed tomography (CT) is an imaging method using digital geometry processing to generate a three-dimensional image of the inside of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation. Researchers have been studying the value of CT scans to detect Chiari-like malformations and syrinxes in Cavaliers and comparing the results with MRIs and other resources. In a very preliminary 2008 French study, researchers CT scanned sixteen CKCS to measure the size of their caudal fossas and to determine standard computed tomography dimensions of the caudal fossa.

Dr. Dominic J. Marino of Long Island Veterinary Specialists (LIVS) reported in October 2007 that evaluation of the entire skull shape and size utilizing Spiral CT technology with 3D reconstruction is currently underway to identify additional mechanisms of syrinx formation. He wrote that CT scanning may enable surgeons to focus on correcting the flow of CSF as the malformation affects its normal passage around the brain and spinal cord and leads to the syrinx formation known as syringomyelia.

-- thermography

Thermography is a non-invasive imaging technique which records thermal patterns. It provides information about the function of the sympathetic nervous system. Thermal imaging has drawn the interest of veterinary researchers as a potential screening test for CM in dogs due to its ability to image dogs without sedation. In a preliminary 2007 study at Long Island Veterinary Specialists (LIVS), Dr. Dominic J. Marino's team found that Cavaliers with CM had “cooler” thermographic patterns when compared with a dog with a normal caudal fossa. Dr. Marino reported in October 2007 that, "based on these very preliminary findings, thermography may be a viable imaging modality to use as a screening tool to detect CLM in dogs."

-- ultrasound

In the same 2008 French study reported under computed tomography above, one dog's syrinx was identified by ultrasound.  The researchers found that ultrasonography probably has too low a s