MRI brain scans can help doctors predict whether people with possible early signs of multiple sclerosis will develop the central nervous system disorder and how severe it will be, a British study concluded.
Until a few years ago, doctors did not officially diagnose MS or start treatment until patients had two episodes of nerve problems in different parts of the body _ flare-ups that could come many years apart while damage silently accumulated.
Now, researchers at the National Hospital for Neurology and Neurosurgery in London say they have proved that magnetic resonance imaging of patients' brains can detect damage around nerve fibers in nearly all of those who eventually develop MS.
The study was reported in Thursday's New England Journal of Medicine.
``It adds to the impetus to put people on drugs early,'' rather than waiting years for a definitive diagnosis, said Dr. Stuart D. Cook, an MS researcher, professor of neuroscience and president of the University of Medicine and Dentistry of New Jersey.
Recent research has found that putting patients on MS drugs at the first sign of nerve inflammation can sharply cut the chances of developing the disorder within a few years, and the National Multiple Sclerosis Society now recommends doing so.
Cook said researchers still must prove that starting treatment early limits damage for decades, not just a few years. That will probably take 10 to 15 more years of following patients, he said.
The first drugs to cut the severity and frequency of MS attacks were not available until a decade ago.
About 350,000 Americans have multiple sclerosis, believed to be caused by immune cells attacking the protective myelin sheath surrounding nerve fibers in the brain and spinal cord. Initially, the body can repair the damage, but over time the nerves become scarred and stop transmitting signals.
Some people merely suffer mild, intermittent symptoms for decades, while others steadily worsen, becoming blind or paralyzed or even dying from related infections.
Diagnosis is difficult, because initial symptoms, such as numbness, muscle weakness or visual disturbances are temporary and can have other causes.
Researchers led by Dr. David H. Miller, a neurologist at the London hospital, gave periodic MRIs to 71 patients followed for 14 years on average.
Among those who had damaged nerve fibers on the initial MRI, 44 of 50, or 88 percent, developed MS; five of the remaining six had signs that they also had developed it. Of the 21 patients whose initial MRIs were normal but who had possible MS symptoms, 19 percent developed the disorder.
The study also found that patients who had more nerve damage generally developed more severe MS symptoms.
A second study in the journal, involving the examination of brain tissue of 10 deceased MS patients, found that even in advanced stages, the brain tries to replace the sheathing on nerve fibers damaged by MS, counter to previous beliefs. Researchers at the Cleveland Clinic Lerner Research Institute concluded the nerve fibers were no longer allowing that repair.