Use of functional magnetic resonance imaging (fMRI) scans to detect leukoaraiosis benefits patients undergoing brain mapping for surgery or other treatments, according to researchers in a study published online in the journal Radiology.
Leukoaraiosis, tiny areas of the brain that have been deprived of oxygen and appear as bright white dots on MRI scans, have long been considered to be a benign part of aging. However, this small vessel ischemia, which is common among people over the age of 60, may affect connectivity in the brain’s network activity, researchers said.
“We know that aging is a risk factor for leukoaraiosis, and we suspect that high blood pressure may also play a role,” said Kirk M. Welker, MD, assistant professor of radiology in the College of Medicine at Mayo Clinic in Rochester, Minn.
Welker and his colleagues studied 36 elderly patients. Eighteen patients had a moderate amount (25 ml) of leukoaraiosis and 18 were age-matched control subjects who had less than 5 ml of leukoaraiosis. All subjects underwent fMRI while performing two tasks: identifying word pairs and performing a visual perception task involving differentiating straight lines from diagonal lines.
The researchers found that while both groups similarly performed the tasks, there were different brain activation patterns between the two. Those with the most leukoaraiosis demonstrated atypical activation patterns. In addition to showing decreased activation in areas of the brain involved in language processing during the semantic decision task, they experienced increased activation in the visual-spatial areas while performing the visual perception task.
“Different systems of the brain respond differently to disease,” said Welker. “White matter damage affects connections within the brain’s language network, which leads to an overall reduction in network activity.”