My understanding is that concussions don't necessarily show up on MRIs. My son did have an inital CAT scan following his injury and maybe a second (I'd have to look it up), but both the neuropsychologist and neuro-surgeon were in agreement that further brain scans would be inconsequential. The simple fact of the matter is that you have to treat the symptoms, and if the sypmtoms are screaming PCS what harm are you doing by following that protocol? Maybe there is a migrane med to consider and even trial, but I don't see how the possibility of PCS can be ignored. Stick with your gut. If you don't like your doctors, don't be afraid to move on. We withstood the condescending judgement of 2 ER docs and a specialist at Children's hospital in Boston before we found docs who really knew what they were talking about.