Insurance denied my brain PET scan even though my doctors know I definitely need it

My insurance denied my brain PET scan because 1. The doctor needing to perform a physical and mental exam 2. The mental exam needs to point to 2 types of dementia: Frontotemporal and Alzheimers 3. The notes did not mention dementia. It was originally ordered because my neurologists suspect I may have a prion disease due to a total inability to sleep with a loss of REM/and deep sleep. They want to look for thalamic hypometabolism. I’m going to try to fight it to get coverage, but I have to get this PET scan. I’ve been waiting a year for some answers and it’s going to be the only thing that gives me some real answers. If insurance continues to deny it, is there any way I can just get the scan regardless and pay out of pocket? This PET scan is currently my only hope and it has to go through. My appointment to get it is still scheduled and hasn’t been cancelled and I still plan to get it no matter what.

I just hate that it’s the weekend and I have to find out about it just now when I can’t get in contact with anyone. I just need reassurance I’ll still be able get it if I pay for it out of pocket, I’m worrying myself sick over it. I have it scheduled for this coming Wednesday at a local hospital nearby. I just need some reassurance to put my mind at ease.