Boston: A Dutch study has found thirteen percent of healthy adults have some type of undiagnosed, likely harmless abnormality in brain.

The study led by Meiki Vernooij of Erasmus MC University Center in Rotterdam, is significant as brain scans have becoming more common and more detailed, and doctors need to know whether to be concerned about it.

The study team examined the (magnetic resonance imaging) MRI scans of 2,000 volunteers over the age of 45.

The study findings may have implications for patients in future. During the routine medical tests, the doctors may urge patients to have surgery or other treatment as a precaution. Patients may force doctors to fix the potential problem.

Dr. Aad van der Lugt, an associate professor in radiology at Erasmus MC University Medical Center in Rotterdam and a co-author of the study, said, “It’s very scary to learn there’s something wrong in your head.

Van der Lugt, said, “Unfortunately, we know little of the natural course of these asymptomatic findings.”

“It may well be that the clinical course and relevance of these unexpected asymptomatic findings differ from those of similar symptomatic findings for which persons seek medical treatment,” he added.

Researchers said that none of brain tumors spotted by MRIs required surgery. The participants, who needed additional evaluation or treatment, were referred to specialists.

More than 7 % showed evidence of brain clot, but there were no symptoms and seemed to be common with age.

About 2 % had a brain aneurysm (a bulge in blood vessel that can burst if it is too big, causing stroke). But 32 out 35 aneurysms were so small that researchers did not suggest any follow-up medical treatment.

Another 1.6 % persons in study had brain tumors, but were non-cancerous. The benign tumors can kill if they grow and shut down vital brain function, so doctors sometimes treat these.

Judy Illes, professor at University of British Columbia, said, “In brain scans to investigate headaches or other problems, it’s not unusual to find a small percentage of unexpected abnormalities. But the new study — one of the largest of its kind which used a state-of-the-art MRI scanner — gives perhaps the best estimate of how often these occur in the general public.”

The study was published in the New England Journal of Medicine.