Bobe-ster: Just out of curiosity, how can the doctor be so sure you don't have an ulcer upon your first visit to him, without having done an upper GI series (barium x-ray), an endoscopy or a colonoscopy? What is he basing such a quick diagnosis on?

I googled CAT scans and skimmed an article or two, and contrary to what Kent said, a CAT scan is a low-risk, non-invasive way to look for tumors and infections in the multiple organs in the abdomen (liver, gallbladder, pancreas, spleen, aorta and kidneys, in addition to the GI tract). Sounds like the doc wants to see if there's an obvious anomaly that he should be targeting before he starts poking around randomly in your innards.

Good luck!