Hi I'm mum to a 10 year old with IIH.
When M had a venogram she had a cannula in her arm. They scanned before adding the contrast - then she had to remain completely still whilst they injected the contrast through the cannula then they scanned again. The container of contrast was HUGE. M was suspected to have had a venous sinuous thrombosis previously as a consequence of other health issues and drugs but suffered no ill effects from the venogram.
We have no experience of stenting.
Hope you get lots of useful info from others, G