n the absence of any pressure, the vein walls will collapse to their natural position. But in many of the venogram images, the jugular vein is obstructed in one particular location, caused by some external force, such as a bony protusion, malfunctioning valve, etc. These images still show blood flow above and below the narrowing. Shouldn't the image show no blood flow below the narrowing, if the vein was to collapse in the absence of any flow?
Also, if blood blow is being driven to the vetebral veins, in the presence of flow resistance in the jugulars, why is CCSVI a problem? Aren't the vetebral veins capable of handling this blood flow like when the person is supine?
Those MRVs are a static image taken after the gadolinium has percolated through the area. if you take a snapshot you might see what you expect, but there is slow flow rather than no flow.
good question about the vertebral vein flow. I see that you will make me think by this exercise and i will figure things out or need to learn things along the way......we really are partners in crime, eh.
I would postulate and argue that these vertebral veins have extra flow that they are not prepared to handle. and not all the blood can exit as fast as necessary. the theory is that this "breakdown" in the blood brain barrier leads to problems.
you guys are tough and insatiable