Brief Answer:
Read below

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

You speak of CT scan, but on the other hand you mention T2 which confuses me a little because T2 is a MRI sequence, there is no T2 on a CT scan.

Anyway the report speaks of diffuse changes in the white matter and suggests as a primary hypothesis for their origin chronic small vessel disease, meaning narrowing of the blood vessels leading to closure of the tiniest of them and small areas of damage due to lack of blood supply. It is a common finding in many people after the age of 60 as our blood vessels undergo changes with age. Their significance depends a little on their degree, the extent of the phenomenon, if only mild with a few scattered areas not that worrying but if more widespread then it is worrying, not in the sense of acute life threatening but in the sense of causing slowing in thinking and movement, with a greater risk of dementia as years go by. I can't see the images and the report doesn't mention whether changes are mild, moderate or advanced, but by the terms used and age of 61 I would say they do seem to be more than they should be for your age. Causes the process may be more advanced in some individuals may be many, but the most common is changes of blood vessels over time due to high blood pressure, diabetes, smoking. So some attention is needed in that regard, identifying predisposing factors (if any - genetic factors may be at play and can't be altered) and address them so that further progress is stopped/slowed.

The other suggested cause is metabolic toxic encephalopathy. That is a term used for brain damage due to many causes such as metabolic changes due to other conditions like kidney failure, thyroid dysfunction or exposure to toxic substances. So to exclude that some routine blood tests as well as a detailed history is needed.

The PRES diagnosis is also mentioned, you do not provide any detail on your history but it is more of an acute event with symptoms such as seizures, vision loss, so since you seem to have received the report at home, not admitted in a hospital it doesn't seem to be the case.

As for the prominence of the ventricles an sulci, since it says according to age it is not a reason for worry. The brains of all of us undergo some shrinking after our thirties which leads to those findings, only if too advanced for ones age would it raise concerns of dementia.

I remain at your disposal for other questions.

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