Did they show you any of the "pictures" and explain the results to you?
I'd even ask for copies of the films/pictures - for future reference- or in case you want to have another dr read them.
What did the MRA show?? did you get a copy of the written report?
You can ask for all of those reports and records, most likely you will need to fill out a request form and maybe pay for the copied pages.

what does artifact mean in medical terms? {something old??}

[weakness in hands,difficulty with speech , ringing in my ears, and whooshing noises as well..]

I had all of those , still do sometimes - from RSI/TOS when my scalene and SCM {neck} muscles got very tight.
the whooshing might be a bruit - is it in time with your heart beat?

Many with thoracic outlet syndrome have vascular symptoms and some have nerve symptoms also.

here's our useful links & info thread about TOS-
http://neurotalk.psychcentral.com/showthread.php?t=84

What kind of work do you do?
whiplash , or other accident, sports, falls?