Re: intestinal exams
An endoscopy and colonoscopy take a "ride thru" the esophagus and sigmoid colon. A CT scan shows a clear picture of the lower bowel (outside) and surrounding organs.
I have never had a small bowel series, but am assuming it is done with contrast much like the CT, but specific to the small intestines.
As for swallowing a "video pill" - same concept as a colonoscopy....takes a look at the inside.