Causes and consequences of cerebral microinfarcts. Characterizing the “(in)visible” lesion

Abstract

Microinfarcts are very small brain infarcts, that have been described in autopsy studies for a number of years. These studies suggest that microinfarcts could play a role in cognitive decline and dementia. For a long time microinfarcts were considered too small to be visible on brain scans of living persons and were coined the “invisible” lesion. Recently, microinfarcts were successfully identified at the UMC Utrecht using high-field strength MRI and later also with more regular MRI. This was an important development for the thesis of Doeschka Ferro, in which she identifies the causes and consequences of cerebral microinfarcts in living persons with the 3 tesla MRI-scanner.

Ferro shows that microinfarcts can have multiple causes, which include small vessel disease, thromboembolism and decreased cerebral perfusion. Moreover, she confirms the suspicion that presence of microinfarcts is associated with cognitive decline and dementia. She also shows that microinfarcts are associated with perilesional injury in adjacent cortical tissue that extends well beyond the visible infarct. This is a highly relevant finding, as it helps to understand how these miniscule lesions can nonetheless have a substantial impact on brain functioning.

Microinfarcts are currently not used in the clinical diagnostics of cognitive complaints. This could potentially change in the near future, as this thesis indicates that acute microinfarcts are a predictor of poor clinical outcome, including higher odds of stroke. Further research is needed on the implementation of this novel MRI marker in daily care and on the development treatment strategies for patients with microinfarcts.