MRI and treatment for Brandy

Hi!!! This is Brandy! She is a 6 year old Saint Bernard who is struggling to walk. Her bones look amazing and they can’t find something wrong with her anymore. They need to take an MRI to find what is wrong with her. She is lovable, playful, and the sweetest dog I have ever had. I’ve spent tons already looking for answers, would like some help to find out what is wrong and help her!