Annhere-
I have not had the test you describe- but there is a special ultrasound examination that Dr. Jordan does ( i do not know if it has a name) and he told me that my circulation was completely cut off by the time my right arm was up to shoulder level.

When I asked him how bad that was relative to other cases of TOS he has seen, he said "pretty bad". I got the options of Botox or surgery, with the strong suggestion that I try the botox first.