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View Full Version : Mini-MRI-scans miss lower syrinxes in 76% of studied SM-affected cavaliers



RodRussell
14th January 2011, 01:42 AM
In MRI studies of 49 cavaliers, Dr. Clare Rusbridge and others found that "Syrinx formation was present in the C1C4 region and in other parts of the spinal cord. The maximal dorsoventral syrinx size can occur in any region of the spinal cord." Seventy-six per cent of CKCS with a cranial cervical syrinx also had a syrinx in more caudal spinal cord regions.

They concluded that, an "MRI restricted to the cervical region may underestimate the extent of SM and the severity of the disease process in the majority of dogs." Therefore, so-called "mini-MRI-scans" of only the cervical region, such as those scans for breeding protocol purposes, may not necessarily locate all syrinx which an SM-affected cavalier may have. They also found that total syrinx size positively correlated with the age of the dog.

See BREAKING NEWS at http://cavalierhealth.org for more details.

*Pauline*
14th January 2011, 02:17 AM
"They also found that total syrinx size positively correlated with the age of the dog."

Onset can happen at any age and severity varies so how can the size of a syrinx correlate with age??

Karlin
14th January 2011, 05:45 PM
Pauline, because it is a progressive condition, the older the dog the larger the syrinx will tend to be. This holds true whatever the age of onset, though most syrinxes seem to appear before age 4 or so (but a dog being free of a syrinx at 4 does not mean it will not get a syrinx). So syrinx size generally correlates to age of the dog. They almost always progress when dogs are rescanned.

Incidentally I am told by Dr Rusbridge that with this study, in no case was a dog not correctly diagnosed as in every case with these dogs, the syrinx appeared within the vertebrae included in a mini scan. So this finding would NOT affect a dog being correctly diagnosed with SM and would NOT alter the grade given to a dog in a single case from this sample.

Where it might make a difference would be in scanning dog for full diagnosis -- this is why neurologists do NOT recommend using miniscans if you suspect a dog has SM and wish to have an accurate diagnosis of syrinx length, location and number. As far as I know ever single low cost scanning centre has made the point that miniscans are for information and grading purposes primarily for breeders and research -- they are not and never have been intended for diagnosing an ill dog for followup care.

I am aware some breeders tell dog owners they should opt for miniscans to save money (because some of them keep stating this online, directly to me, and to pet owners who mention it to me!)-- but this is poor advice and can be wasteful of money, time and accurate diagnosis for owners as generally they will just have to rescan with a full scan to get follow up care for a sick dog. The miniscans do not include actual guidance on the care of an affected dog.