How frustrating. Did the MRV follow the Haacke protocol? Did it extend far enough down to where the jugulars meet the subclavical vein (a common problem area)? Do the images look sharp or crappy? If what you describe as a helix is a bright area, then a twist that is darker, then a bright area, did they give any explanation for that? And how the heck did you get your neuro to order an MRV?
Are you located anywhere near an IR who is testing and treating? A doppler is will show different things than the MRV, most particularly the reflux.