this is the fellow that has looked at a couple of our TIMS locals:
perhaps he can refer you to the right people closer to your location...
this is one part of the answer to your question, and it's from the 'glossary' sticky right at the top of the main ccsvi topic:
Magnetic resonance venography
The type of magnetic resonance imaging (MRI) used to visualize veins. The MRV uses the same machine as an MRI, but a special computer software allows it to only extract generated-by-blood images, as it flows through the veins. These images give doctors a rough idea of whether blood flow through a vein of interest is affected by blood clots or other disease processes