Brain Lesions Predict MS Progression
TUESDAY Aug. 28, 2007 -- Certain types of lesions on the brains of multiple sclerosis patients may help predict the severity of disease progression and the accompanying disability, researchers are reporting.
"This is a new way to try to understand what is changing in the tissue of the patient's lesions," said lead researcher Dr. Rohit Bakshi, associate professor of neurology and radiology at Harvard Medical School and director of Clinical MS-MRI at Brigham and Women's Hospital and Partners MS Center, in Boston.
The new findings, based on magnetic resonance images of the brain, may help doctors both diagnose multiple sclerosis more accurately and identify patients at greater risk for disease progression and disability, said Bakshi, a neurologist and neuroimager and senior author of the study, published in the September issue of the journal Radiology.
"The standard MRI measurements are poor at telling us how severe the disease is and telling us how patients are likely to do several years later, how the disease is going to progress and respond to therapy," Bakshi said.
Bakshi and his colleagues used an MRI image called a T1-weighted image and found that specific lesions on that image seemed to predict how severe the disease would get.
"The type of lesions we are describing are relatively new," he said. "Called T1 hyperintense lesions, they look bright when you look at the image." They are different than the lesions known as T2 hyperintense lesions, he said.
MS affects about 400,000 people in the United States, most of them women between the ages of 20 and 50, the National Multiple Sclerosis Society estimates. The disease is chronic and marked by the destruction of myelin, the protective layer surrounding the body's nerve cells. As the disease progresses, it can affect many bodily functions and can result in visual and speech problems, memory loss, muscle weakness, loss of coordination and other problems.
"This is the first time that hyperintense T1 lesions have been correlated with the progression of disease," Bakshi said.
The two most common types of multiple sclerosis are called relapsing-remitting and secondary-progressive disease. People with relapsing-remitting MS have flare-ups of symptoms, followed by periods when the disease does not worsen. Those with secondary-progressive MS have a period of relapsing-remitting disease and then get steadily worse.
In the study, Bakshi reviewed the T1 MRI data of 145 patients, 112 women and 33 men. Of those, 92 had relapsing-remitting multiple sclerosis, 49 had secondary-progressive MS, and the status of four patients wasn't known.
The researchers found 340 T1 hyperintense lesions in 123 patients. These lesions were more likely to be found in patients with secondary-progressive disease. The researchers also found that 71percent of those with secondary-progressive MS had multiple T1 lesions, but just 46 percent of the relapsing-remitting patients did.
The more T1 hyperintense lesions a person had, the more likely they were to be physically disabled, to have disease progression and to have brain atrophy, another marker of the disease.
"Seventy-eight percent of the patients had at least one T1 hyperintense lesion," Bakshi said. "The average number was three per patient."
While researchers have known about hyperintense T1 lesions for years, it is understandable that it has taken a while to find the link between them and disease status, Bakshi said. "The hyper-intensity is not very obvious to the casual observer, so finding it is subtle. Unless you have a trained eye, you will miss it."
Bakshi concluded: "Patients who have a more severe form of MS have a median number of three [hyperintense T1 lesions]; the relapsing-remitting patients have only one."
Dr. John Richert, executive vice president for research and clinical programs at the National Multiple Sclerosis Society, praised the study findings and said they could prove useful. "To my knowledge, this is the first time anyone has made this correlation," he said.
"The correlation was modest, but it was there," he added, and needs to be replicated by other groups of researchers, just as all scientific research should.
"This is potentially important, because it will stimulate more research into what it [the hyperintense lesion] actually represents in the damaged tissue," Richert said.
Tracking the lesions may also turn out to be useful when evaluating new drugs for MS, he said.
To learn more about MRIs, visit the American College of Radiology.
Posted: August 2007