SOURCE: Radiology, news release, Sept. 10, 2014
FRIDAY, Sept. 12, 2014 (HealthDay News) -- There's a strong connection between the severity of disease and the loss of myelin in the brain's gray matter for who have multiple sclerosis (MS), a new study says.
MS causes the loss of myelin, the fatty, protective sheath around nerve fibers that is most abundant in the brain's signal-conducting white matter. That's why MS is typically considered a disease of the white matter, the researchers noted.
But myelin is also present in smaller amounts in gray matter, which is the brain's information processing center, and the researchers used MRI to spot the impact of that loss as well, according to the study, published online Sept. 10 in the journal Radiology.
"The fact that MS patients lose myelin not only in white but also in gray matter has been proven by earlier post-mortem pathological studies," Vasily Yarnykh, an associate professor in the radiology department at the University of Washington in Seattle, said in a journal news release.
"However, the clinical significance of the myelin loss, or demyelination, in gray matter has not been established because of the absence of appropriate imaging methods," he added.
Yarnykh and colleagues used a new type of MRI called MPF mapping to examine the brains of 30 MS patients and 14 people without the disease. Eighteen of the patients had relapsing-remitting MS, the most common type initially diagnosed, and 12 had secondary-progressive MS, a more advanced form of the disease.
"The major finding of the study is that the loss of myelin in gray matter caused by MS in its relative amount is comparable to, or even larger than, that in white matter," Yarnykh said.
"Furthermore, gray matter demyelination is much more advanced in patients with secondary-progressive MS, and it is very strongly related to patients' disability. As such, we believe that information about gray matter myelin damage in MS is of primary clinical relevance," he explained.
The researchers also said that the new MRI technique could be useful in assessing new treatments for MS and in helping manage the disease.
The U.S. National Library of Medicine has more about multiple sclerosis.