When I had my TBI my symptoms are all concussion symptoms but when my PCP did the imaging (3 days later) it showed brain contusion (literally bruising on the brain). After that several MRIs and no more bleeding but showed minimal brain softening (encephalomalacia) and will show that rest of my life. Not that anything can be done for that but is just an evidence there was a mild TBI.

They can look at your vestibular system, sinuses and so many other things just to rule out and give you peace of mind. Sometime subtle CSF leaks can cause headaches etc., which may be able to fixed. Anyway the chances of all these are very less if it is a mild concussion. I didn't know I was claustrophobic until I got into the MRI. So next time my doctor gave me Xanax and sure I tolerated pretty well. By the way that is how I found out Xanax helped me with Dizziness too. As Mark mentioned close your eyes before you they slide you into the machine and never open until you get out. It is not that bad after that. They also talk to you during the whole process explaining what is going on.