BTW, MRI can size veins very accurately, as Dr. Haacke has been trying to tell people. Doppler ultrasound (or IVUS) can guide measurement. Much can be measured from an MRI, depending on resolution. Whether one is available, or gets used, can't be predetermined.
If some other kind of impediment is already obvious by venography, CAT scan, or any other way, the presence of a web or septum may or may not affect treatment. It is up to the IR or vascular surgeon, or neurosurgeon or other specialist I may have asked for, or been referred to, to decide on and know how to use whatever armament, regardless of what precious metal it is associated with.

I rely on them to know the appropriateness of MRIs, IVUS, venography, Doppler or plethysmography. I think having the right information is important when choosing my doctor, and discussing my treatment.
The best practices evolve and replace the old best practices. They are a snapshot only, and may last for one procedure or many.
I am still asking questions. I don't want to claim any agenda, or to know any of the answers for anyone but myself.
Let us agree to disagree. I have said what I think.