You don't want to overlook an emergency. If you have a fever, go in. Fever, sweating, pain and vomiting are signs of an organ being inflamed or infected. Emergency surgery is very painful so you want to avoid it by getting it removed asap. The ER doctor told me I needed it removed, and the first surgeon refused. I got a second opinion and the second surgeon took me in. By then my gallbladder was barely working. You do not need an MRI. I only had an ultrasound.