The small bowel study is the probably the common diagnostic test in the gut. It is used to diagnose a whole host of abnormalities that show up on x-ray (e.g, ulcers, cancers, obstructions).CT shows the organs from foot-on point of view and probably more easily diagnose tumors, cysts and thngs of that nature.The scintigraphy studies only transit. It is similar to the sitz marker study in that regard.quote:What is the difference between the two tests, what does the one show that the other doesn't? Why would both tests be ordered, isnt it a kind of duplication in a sense.