@crumblecookie I had the IR angiogram with manometry prior to my surgery with Dr. Nakaji. He measured the pressure gradients at 18 different locations in the brain both in neutral and flexed neck positions. My gradients were as low as 4 in some places and as high as 18 in others. It’s been a while now since I was doing all of my research and reading all the studies but I seem to recall that anything above 8mm Hg was considered significant.