understand ct report on brain

I recently (last week) had to have a carotid endarteractomy because of 77 percent stenosis in one carotid. Turns out the other was only 5 percent. I am 61 years old with normal blood pressure and choles. and no factors except 10 years ago I was a smoker for 30 years. The recent ct said precontrast imaging of the brain demonstates mild generalized cerebral atrophy, physiologic for age. There is mild to moderate patch hypodensity in the deep white matte of both cerebral hemispheres, consistent with small vessel disease age indeterminant. No acute cortical ischemic change or bleed. No hemorrhage or extra-=axial fluid collection. No mass.
ct angiogram of the intracranial circulation demonstrates isolated atherosclerotic calcificaion affecting the left pre-cavernous and cavernous carotids without stenosis. The remainder of the intracranial circulation demonstrates no occlusion, stenosis,or significant atherosclerotic irregularity.

I am just getting over the operation and I couldn't think fast enough to understand what this all meant. Is any of this reversable, or am I going to either have a stroke or alzheimers? Is the hypodensity due to the fact that I had less oxygen to the brain for the time my carotid was blocked?