Brief Answer:
ischemia- reduced blood supply, infarction- died off because of less blood

Detailed Answer:
HI, thanks for using healthcare magic

Ischemia/ischemic disease means that there is reduced supply to an area. Infarction means that reduced blood supply to an area has caused it to die off/ not work or function any longer.

Chronic means long term, has not occurred recently. Microvascular means involves the small blood vessels.
White matter refers to an area of the brain.

Chronic infarction means that reduced blood supply to an area has caused that area to die off/ not work any more. This reduced blood supply did not just happen recently but a long ago.

Chronic white matter microvascular ischemic disease refers to reduced blood supply in the small blood vessels that go to the white matter parts of the brain.
There are some persons with high blood pressure, diabetes , smokers, high cholesterol , that can have these changes.

A stroke occurs when there is reduced blood supply to an area of the brain.

Controlling risk factors such as blood sugar, cholesterol, blood pressure, eliminating smoking--- would reduce the chance of further changes.

I hope this helps, feel free to ask any other questions

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