What is an old infarct?

An old infarct is an area of permanent scarring or a small, fluid-filled cavity left behind by a past stroke. This happens when a blood vessel gets blocked, cutting off oxygen and causing a small piece of brain tissue to die. While some strokes cause obvious symptoms like speech loss or weakness, many are silent stroke. These are events that are so small or located in areas that don't produce immediate symptoms, causing them to pass entirely unnoticed until they are discovered on a scan.

Old infarcts are classified by their mechanism and location:

• Lacunar infarcts: the most common type of silent stroke. These are tiny, deep scars caused by long-term damage to the brain's smallest blood vessels from high blood pressure or diabetes.

• Cortical infarcts: scars on the outer surface of the brain, usually caused by a larger blood clot traveling from the heart or neck arteries.

• Watershed infarcts: scars that form in the border zones between major blood vessels, typically from a sudden, severe drop in blood pressure or a cardiac arrest.

Symptoms of an old infarct

By definition, an old infarct caused no recognised neurological symptoms at the time it occurred. However, the cumulative burden of silent infarcts over time is associated with a progressive spectrum of subtle and then more significant consequences:

• Subtle cognitive slowing, reduced processing speed, and mild memory difficulties

• Reduced executive function, affecting planning, multitasking, and decision-making

• Mild gait changes, a slightly shortened stride or reduced confidence on uneven surfaces

• Low mood, apathy, or emotional lability from frontal subcortical circuit disruption

• Increased risk of future clinically apparent stroke

• Progressive accumulation increasing the risk of vascular dementia over time

Many people with one or several old infarcts on MRI have no detectable symptoms on standard clinical assessment, yet careful neuropsychological testing often reveals subtle processing speed and executive function deficits.

What causes old infarcts?

Old infarcts develop from the same mechanisms as clinically apparent strokes. Contributing causes include:

• Chronic hypertension is the single most important cause of lacunar silent infarcts, causing progressive small vessel disease and penetrating artery occlusion over years.

• Diabetes accelerates small vessel wall damage through glycation of vessel walls and endothelial dysfunction, independently driving lacunar infarct formation.

• Atrial fibrillation causes cardioembolic strokes from clots forming in the left atrial appendage. Many embolic strokes, particularly small ones, are clinically silent.

• Atherosclerosis of large and medium cerebral vessels causes both large vessel and small vessel occlusions contributing to silent cortical and subcortical infarcts.

• Smoking causes direct vascular endothelial damage accelerating both large and small vessel cerebrovascular disease.

• Elevated homocysteine damages vessel walls and promotes a prothrombotic state, independently associated with lacunar infarct burden.

• Dyslipidaemia contributes to arterial stiffness and atherosclerosis driving cerebrovascular disease.

• Obstructive sleep apnoea causes repeated nocturnal hypoxia and blood pressure surges that accelerate cerebrovascular damage.

How are old infarcts detected?

Old infarcts are detected primarily through brain MRI, which is far more sensitive than CT, especially for the small lacunar infarcts that make up most silent strokes. Blood tests identify the modifiable vascular risk factors driving their formation and assess the risk of future events.

Brain MRI Elfcare’s full-body MRI easily spots past strokes (old infarcts), showing up as permanent scars on the brain. The scan counts these scars, measures their size, and determines whether they happened deep inside the brain or on its surface. By looking at these spots alongside overall tissue loss and tiny bleeding leaks, the MRI provides a complete picture of your total blood vessel health, helping doctors stop future strokes before they happen.

Blood tests cannot detect old infarcts but identify the modifiable vascular risk factors most strongly driving their formation and recurrence. Relevant markers in Elfcare's panel include:

• HbA1c and glucose: diabetes is a major driver of small vessel disease and lacunar infarct formation

• Total cholesterol, LDL, HDL, ApoB, and Lipoprotein(a): dyslipidaemia drives atherosclerosis and cerebrovascular disease

• Homocysteine: elevated levels are independently associated with lacunar infarct burden and cerebrovascular disease

• CRP: systemic inflammation drives vascular endothelial damage and accelerates atherosclerosis

• Creatinine and eGFR: chronic kidney disease is closely linked to cerebrovascular small vessel disease

• TSH: thyroid dysfunction affects cardiovascular risk profile and cerebrovascular health

• Ferritin and haemoglobin: anaemia and iron dysregulation affect cerebral oxygen delivery and vascular health

Why early detection matters

An old infarct is not a historical curiosity. It is a warning signal that cerebrovascular disease is present and active, and that the risk of a future clinically apparent stroke is substantially elevated. People with silent infarcts on MRI have a two to three times higher risk of future stroke compared to those without. They also have significantly higher rates of cognitive decline and progression to vascular dementia. Yet the same vascular risk factors driving silent infarcts, hypertension, diabetes, dyslipidaemia, and elevated homocysteine, are all modifiable with treatment. Identifying silent infarcts on Elfcare's brain MRI creates the clearest possible motivation for aggressive risk factor management, at a point when the next stroke, which might not be silent, can still be prevented.

How Elfcare can help

Elfcare's full body MRI includes comprehensive brain imaging as standard, directly identifying old infarcts, characterising their type and distribution, and assessing the overall burden of cerebrovascular disease. Finding one or more old infarcts on a routine health check MRI is one of the most clinically important incidental findings possible, providing objective evidence of past cerebrovascular events that demands risk factor assessment and aggressive preventive management.

Our blood panel covers the complete vascular risk profile including HbA1c, lipids, homocysteine, CRP, and kidney function, identifying every modifiable driver of future infarct formation that can be addressed through treatment and lifestyle change.

If our MRI or blood tests identify old infarcts or a high vascular risk profile, we take care of further diagnostics or refer you to the appropriate specialist.