Hi and Welcome Jo-Ann!
I had a carotid endarterectomy in 2001 in which they removed the excess plaque from the carotid artery. Generally the concern seems to begin when the blockage is about 70% or above and/or you are showing symptoms such as TIA's, or you've had a stroke...a person can show a narrowing in most any blood vessel of the body, due to plaque, and the older we get the greater likelihood of it happening - perhaps this is what this is? I'm wondering why you had these tests done? What symptoms you are having at the present time?
Your neurologist is sure to be able to answer these questions for you, Jo-Ann, and I truly hope they are positive answers!!
Please stop back by and let me know how you are doing!?