I'm just back from a conference with the neuroradiologist at Stanford who oversaw my MRV. He worked with Dake on the stented MSers. I won't go into our conversation here-my IJVs are open on both sides except for some flattening at C6-7 and like yours, my blood is flowing normally--no slowed perfusion.
The azygous vein drains the trunk & flows upward into the vena cava along with the IJVs that drain the head. The azygous is difficult to image. Apparently, ultrasound cannot image it because it is in the chest behind bony structures. The wand from the ultrasound needs to be pressing against tissue to image.
MRV doesn't get it very well--he showed me how my azygous appears on the slices, then fades away--because as the blood reaches the level of the vena cava, the vein turns horizontal and travels in the same plane as the MRV slice, thereby becoming almost invisible.
He said the only accurate way to image the azygous is with venograms. In their experience, none of the patients they venogramed had azygous stenosis. He said he has never seen it. He and Dake do not know how Zamboni determined the azygous was involved in so many cases. I can't remember what their speculation is.
We talked a lot about how Dake and his team feel MRV is the way to go to image the veins, not ultrasound. The NMSS grant they have applied for is to double blind MRV imaging. We also talked about stenting & angio trials at Stanford.
I came away with more questions than I went in with. I feel like CCSVI is more complicated than I ever could have guessed. I am also more concerned for the future of CCSVI, at least in the U.S.