Prior to an adjustment of your atlas (C1), I would definitely get the “dedicated imaging” that Dr. Smith has suggested. If there’s any risk of that adjustment tightening up the space between styloids & C1 further, it would be a terrible idea to do it. On the other hand, the adjustment might move it further away from your IJV & could help reduce your vascular symptoms. Such a tough call to make but I would err on the side of caution & see what the scan says.