What you’ve said means that you have a lot of lesions, spread across both halves of the brain, but that they are not sure of the cause. Chronic ischemia means long-term blood flow problems (and therefore normally stroke I think). Neuro-degenerative is not very specific - it basically means damage to the neurons (the cells of the brain). There are lots of causes of this though, so it’s horribly vague. Plaques just means scars / lesions / areas of damage.
So sorry, there isn’t sufficient info to make an informed guess from this.
Actually, I’ve just read what you’ve written again and I’m confused. The words “high” and “attenuation” do not normally appear together. In fact, they are sort of opposites!
I am neither qualified nor have all the info, but if your symptoms started only a couple of months ago, I think it is pretty likely that you don’t have MS - it doesn’t normally present in this way. There are one-off infection-driven conditions like ADEM that can cause lots of lesions in a short time though, so it may be that you have something like that - in which case, and with any luck, you will be able to put this behind you soon.