The extremely small (<3 mm) brain lesions frequently identified on MRI brain scans are often considered as a benign part of “normal aging.” However, recent evidence suggests that, when present, they more than triple the risk for stroke and stroke-related death in asymptomatic middle-aged and older adults. In addition, larger lesions (3 mm or greater) increase the risk for stroke eightfold. Patients with both size lesions raises the stroke risk almost ninefold.

The researchers warned physicians not to dismiss the potentially adverse side effects of such small lesions, even though they do admit that the findings are “conservative”. Lead author Gwen B. Windham, MD, an associate professor of medicine in the division of geriatric medicine, said, “These results potentially will help us better understand early pathological changes that develop in the arterial system in the brain. It also is a step toward understanding the risk, what these lesions mean, and what we need to do about them clinically in the future.”

The researchers reviewed data from 1,884 subjects in Atherosclerosis Risk in Communities (ARIC) study. Participants were between ages 50 and 73, and they were invited to undergo brain MRI between 1993 and 1995. The follow-up period occurred 14.5 years later, wherein they found 157 clinical strokes, 50 stroke-related deaths and 576 all-cause deaths. 89 percent of strokes were ischemic. Of the patients who did not experience a stroke, 90 percent had more than 10 years of follow-up.

Despite the evidence in the study, the findings have not changed imaging protocols because more definitive research is needed. However, clinicians should take the presence of lesions smaller than 3 mm seriously.

Imaging Protocols and Study Sources

    Ann Intern Med. 2015;163(1):22-31. doi:10.7326/M14-2057.

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