Basically, there's a belief that the blood not draining fast enough is resulting in iron build up in the head, which triggers the auto immune response.

That's the simplest way of putting it I think, correct me if I'm wrong. MS is the result of a vascular condition acting as the catalyst to kick start the disease process in some folks.

There's probably many walking around with CCSVI without MS, but the important thing is they're finding that many with MS have narrowing of the jugglar veins.