Microinfarcts

Microinfarcts are tiny areas of brain tissue that have died due to ischemia, usually detected only by microscopic examination. They are small foci of liquefactive necrosis, typically less than a millimeter to a few millimeters in diameter, and occur most often in the cerebral cortex and deep gray and white matter. They result from occlusion or dysfunction of small penetrating arteries, often in the setting of small vessel disease related to hypertension, diabetes, and atherosclerosis, or following microembolic events. Microinfarcts may occur singly or in greater numbers and are frequently found in autopsy studies of elderly individuals and those with dementia or vascular risk factors. They may contribute to cognitive impairment and vascular dementia, particularly when widespread.

Detection and diagnosis: due to their microscopic size, microinfarcts are usually not visible on standard radiologic imaging and are identified histologically after tissue examination. Advances in high-field MRI and specialized sequences have allowed limited visualization in select cases, but many microinfarcts remain radiologically silent. Pathologic examination shows small foci of neuronal loss with surrounding gliosis and microglial activation.

Clinical management focuses on reducing vascular risk factors and preventing progression, including blood pressure control, glycemic management, lipid lowering, and antithrombotic strategies when indicated. The relationship between microinfarcts and dementia is an active area of research, with ongoing studies into their role in cerebrovascular and neurodegenerative disease.