My 12 1/2 year old lab/sharpei mix has started having seizures. She has had 4 in two days. I took her to my vet and they did blood work that came back negative for any issue. The vet thinks that the seizures could be caused by a tumor that is affecting her central nervous system. I don't want to put her through the process of an MRI -- she's already "freaked out" enough. Can you give me a second opinion? I'm really at a loss as to what to do. Thanks.