I would forego the CT scan and would ask for a HIDA scan. That would show how well your gallbladder is functioning. You may not have any stones, but have acalculous cholecystitis which is no stones but your gall bladder is not working, and infected chronically or acutely. The test is done in imaging with an IV and a small amount of "radioactive fat" is injected and travels to your gallbladder and mimics the effects of eating a fatty meal. The test will show how well your gallbladder empties over a course of an hour or so. It was painless to me and showed that my gallbladder was non functioning and working at under 1%. When I had it removed it was full of adhesions, scar tissue and was rather sickly looking. No wonder I felt so bad!!! My gallbladder ultrasound was "normal" since it showed no stones. Good luck to you.