Hello and Welcome,
I have to say, that is a really weird way for them to describe it!! Did they mention anything about crowding or a herniation? If it is Chiari, the Dr that took a look at your MRI pics does not seem to know a lot about Chiari otherwise I think it would be described differently.
There are different options that it could be:
First, you have the crowding in your brain but not a large herniation, this would be called Chiari 0 and will be very hard to get dx'd with unless you see a Chiari specialist. Most NS stand by the criteria that if you herniation is not at least 5mm, they won't do anything about it. The problem with that is, if you have crowding w/blockage of CSF flow, you can have symptoms just as badly as someone with a 10mm herniation. A true Chiari specialist will know the difference.
Secondly, you do have the 5mm or more herniation and it is just not being recognized. This happened to me, no mention was made on my MRI report and I was left for 6 months longer, rapidly getting worse and with no diagnosis.
So, my first question...when do you see this NL to go over your MRI? Be very clear to him/her that you want to address this. NL's are not the right Dr to be making decisions regarding Chiari and if they are good, they will refer you to a NS.
If that doesn't happen, you will need to do it yourself. Here is a list of specialists that other members here have used and liked, be careful to research them on you own too.
http://www.medhelp.org/posts/Chiari-Malformation/LIST-OF-CHIARI-SPECIALISTS/show/1293483
I can't stress enough how important it is to get a NS to look at your scans if there is any likely hood that it's Chiari!! Unfortunately, with this condition, most of the time we have to fight for ourselves!! This site is a really good place to get support while you are going through this, so please make use of it.
Take care
Carolyn