Brief Answer:
Read below

Detailed Answer:
I read your question carefully and I understand your concern.

The report does not suggest any threatening lesions, or lesions which should cause any major symptom.

The first part speaks of the carotid arteries, the two vessels (one on the right and one on the left) which supply with blood the anterior part of the brain. The exam notes atherosclerosis, changes of the vessel walls due to deposition of fatty material. Atherosclerosis of the vessel wall is due to damage of vessel wall by factors like high blood pressure, diabetes, smoking, high cholesterol etc.
Now if these changes are marked they narrow the vessel they can obstruct blood flow to the brain. I do not think that is your case or the report should have noted also the degree of the stenosis (narrowing) in percentages, the fact it doesn't do that indicates there is no marked narrowing. Another issue which may arise from atherosclerosis, is that it can lead to formation of thrombi which can cause detach and obstruct a distant blood vessel (cause a stroke).

The second finding of the report is chronic microvascular ischemia. It mean that your smallest caliber vessels are narrowed and there are changes due to lack of blood supply in the tiny areas these vessels supply. This process happens in many people, to a degree it is a part of aging (as our body ages the vessels do as well), so no reason to panic, but can be accelerated the same factors of high blood pressure, diabetes, smoking, high cholesterol etc.

So from a practical point of view, while there is no major brain lesion, your blood vessels are undergoing change. These changes can lead to brain damage in the future, either by a major stroke (from the carotid arteries) or due to summation of the micro-vascular changes.
The management to prevent that from happening or at least delay it as much as possible is similar, control of the risk factors when present (high blood pressure, diabetes, smoking, high cholesterol, obesity etc), a blood thinner like aspirin to prevent formation of thrombi and a statin (drugs which lower blood lipids and stabilize vessel wall).

I remain at your disposal for other questions.

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