Acute CT Brain
Chronic ischaemia

Key points

  • Chronic ischaemic changes commonly seen on brain CT include small vessel disease, old lacunar infarcts and old territorial infarcts

Small vessel disease

Generalised low density of the cerebral white matter is a common sign of chronic ischaemia due to small vessel disease. The finding is associated with vascular risk factors such as smoking, diabetes and hypertension. Many patients with chronic small vessel disease also have generalised loss of brain volume.

Chronic small vessel disease - CT brain

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Chronic small vessel disease

  • Patchy low density of the cerebral white matter is a sign of chronic small vessel disease

Lacunar infarcts

A lacunar infarct (lacuna = small lake) is an area of brain cell death due to a focal ischaemic event. The small middle cerebral artery perforator branches are particularly susceptible to lacunar infarcts.

Acute lacunar infarcts may not be visible with CT imaging as the development of well-defined low density foci takes days to weeks.

Old lacunar infarcts - CT brain

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Old lacunar infarcts

  • Old lacunar infarcts appear as small areas of low density on CT
  • These lacunar infarcts are in the typical distribution of the middle cerebral artery perforator branch territory

Old territorial infarcts

Although acute infarcts may not be clearly visible, over time cell death results in low density in the area affected. Old territorial infarcts appear as well-demarcated areas of low density with replacement of both grey and white matter.

Old territorial infarct - CT brain

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Old territorial infarct

  • The current CT shows a well-demarcated rectangular area of low density replacing both grey and white matter
  • This is the typical appearance of an old infarct - in this case involving the left middle cerebral artery territory
  • The previous CT - performed at the time of the acute event 3 years earlier - is shown for comparison
  • Also note the generalised loss of brain volume over time - enlargement of the sulci

Page author: Salisbury NHS Foundation Trust UK (Read bio)

Last reviewed: November 2016