(Agencies)
Updated: 2007-11-01 20:10

Thirteen percent of healthy adults have abnormalities in their brains without even knowing it, according to new research published in the New England Journal of Medicine Wednesday.

This study, led by Dutch researcher Meike Vernooij of the Erasmus MC University Medical Center in Rotterdam, analyzed the MRI scans of 2,000 healthy individuals with an average age of 63 with no signs of brain problems.

It found that more than 7 percent showed evidence of a brain clot, but the clots were too small to produce symptoms and seemed to be more common with age.

Nearly 2 percent had a brain aneurysm, which is a bulge in a blood vessel that can burst if it becomes too big, causing a stroke. But 32 of the 35 aneurysms were so small, the researchers did not suggest follow-up medical treatment.

These findings may have implications for patients in the future: As more of these abnormalities are spotted with more sophisticated equipment during routine medical tests, some doctors may urge patients to have surgery or other treatment as a precaution. Or some patients may push doctors to fix the potential problem.

One of the researchers Van der Lugt said that tracking such "incidental" abnormalities "will hopefully provide more information that will be useful for both researchers and clinicians."

However, experts say that MRI scans are thought to be safe, but caution that screening healthy people for brain abnormalities does not make sense at present. If the scans show a brain infarct, for example, there is nothing doctors can do to treat it.