Is it with AND without contrast? The combo can make a big difference.
Having said this, they've done your brain..OK that eliminates a lot of issues ...
http://www.aafp.org/afp/980215ap/poncelet.html It's laid out here in the charts[it's also up in those 'stickies'!]. Keep in mind that diagnosing any PN [ideopathic, toxic, inherited or immune] is a long process of elimination! Eliminating any other more easily determined neuro issues. Look at the 'stickies' at Liza Jane's lists of tests...they about cover almost all PN related issues. Now, don't go out and demand all of these, just take a look at them and see how your doc is progressing along these lists and the 'Poncelet' methodology... Be very SURE you get copies somehow of the test results...they will go with you wherever you end up, and you can learn a LOT from them...even or especially the blood tests. Lots to learn!
Doing the neck is quite reasonable as there can be occasions when we mite have fallen as a kid or adult, or been in and accident that we don't think is important NOW, but really mite be a clue to your issues.
The whole thing is no big deal, if they find nothing? Thats good! But it also means there is a likelihood for more testing. Having run almost the gamut for the PN [Really CIDP in my case-auto-immune] and two other immune issues since I got the PN, I have to say I have been thru more MRI's than I care to recall.
I'm just surprised that they are only doing the 'neck' and not more to be really sure... I had the head, neck and whole spine done at the onset...but then I'd been active in a sport which can cause traumatic impacts..etc. that I won't go into.
Brain scans rule out MS, and tumors and vascular blockages and all sorts of things I can't even imagine! That THAT part is clear is really a GOOD THING! So think positive for all this. To me? The jury is out until all the tests are in!
It took me six months to realize the neuro I'd first had wasn't 'working' for ME and Found another and it took another six months to get the tests I needed and the treatments I really needed!
Oops! Just realized you've likely completed your test already... Do let us know. Remember that 'nothing' can be a good thing? BUT don't give up and keep looking. Hope always! - j