Medicare Declines to Cover Virtual Colonoscopies

AP coverage of the decision

Seems logical to me, as much as I dislike colonoscopies the evidence isn't quite there (from what I've seen) that virtual colonoscopies are as effective, and they don't address what you do when you find something (polyps and such can be removed during the same procedure with a colonoscopy.)

FDA bowel prep guidelines

FDA medical recommendations for bowel prep for colonoscopies.

It's dry and technical reading, but if you want to understand the different bowel preps that get recommended these days and why, this is a starting point.