Hi Annhere,
Yes, I've had the MRA/MRV/MRI. My report is very long and dense, so I may be missing something, but I don't see any place where it indicates a specific measurement in reference to compression. It has more general references to compression/stenosis of the subclavian artery and multiple veins (e.g. subclavian, axillary, cephalic, jugular etc. etc.) It also indicates interscalene triangle fibrosis and more fun stuff.
Sorry I couldn't help with the specific info you requested but I wanted to be sure you got a response. Pls. feel free to PM me if you would like.
Good luck!