Stroke And Brain Lesions: Heightened Risk Comes Even With Tiny Abnormalities

Small brain lesions are sometimes disregarded by clinicians. Yet new findings published in the Annals of Internal Medicine reveal that these shouldn't necessarily be taken so lightly. In fact, they could be a sign of heightened stroke risk or even death.

"The lesions on the brain imaging were very small, less than 3 millimeters, and are typically ignored in clinical practice," said lead study author Dr. Gwen Windham, an associate professor of internal medicine and geriatrics at UMMC, in a news release. "This is because we have been uncertain as to their meaning; no studies have looked to see if these very small lesions are related to important clinical outcomes. Our findings suggest they are at least as important as 3 millimeter or larger lesions that are typically considered abnormal, even in absence of other lesions."

During the study, researchers analyzed brain magnetic resonance imaging (MRI) data from close to 1,900 individuals participating in the Atherosclerosis Risk in Communities (ARIC) Study who were 50 to 73 years of age with no prior history of stroke. Their health was then tracked for up to 15 years. The study sample included a mix of bi-racial and middle-aged patients, which typically differs from prior studies that have focused on older and largely white samples.

Findings revealed that stroke mortality risk was up to three times greater in those with small lesions. Furthermore, people with both very small and larger lesions had seven to eight times higher the risk of those with poor outcomes.

"Some of these lesions are so small they have the resolution of a single pixel," said Dr. Thomas Mosley, director of the Memory Impairment and Neurodegenerative Dementia (MIND) Center at UMMC and senior scientist on the study. "In clinical practice, we would typically ignore these tiny lesions as insignificant. The assumption has been that these very small lesions probably are not particularly consequential, but, in fact, they appear to be."

Statistics show that more than 800,000 strokes occur every year in the United States, according to the National Institute of Neurological Disorders and Strokes--making this health issue a leading cause of death in the country and one of the more serious long-term disabilities of any other disease.

With future studies, researchers hope to learn more about how to identify certain high-risk markers that impact some, and how to spot them.

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