http://www.ctv.ca/CTVNews/WFive/2010...update_100409/

Lots of Information here.

Also you asked about MRV, must have contrast dye.

The Interventional Radiologist will know how to run the following scans:

- a 2D time-of-flight MRV through the head and neck down to the subclavian.
- a time resolved MRA/MRV of the head and neck coronally to the aortic arch.
- flow quatification through the straight sinus, the jugular (upper and lower) and coronally through the jugular/subclavian and brachiocephalic veins in one plane, to check for reflux flow and slow flow.
- SWI if available to check for the small venous structures and iron content

The MRV looks for blockages in both the jugulars and the azygos, but won't find the telltale reflux or backflow of blood. (Doppler does)

That's an important distinction since some people don't have blockages -- but they do have problems with a valve in a vein or with a flap within a vein that causes reflux.

Or go right to the Venagram, and get the procedure at the same time.