Medicare has decided not to pay for virtual CT colonoscopies.
Medicare does cover regular invasive colonoscopies.
The x-ray procedure is a substitute for invasive colonoscopies. It is cheaper and non-invasive, but does involve x-ray radiation.
The invasive colonoscopy allows the surgeons to excise any pre-cancerous polyps found, saving a second procedure.
If the CT colonoscopy finds pre-cancerous growths, then a regular colo must be done to excise the polyps, thus causing two procedures instead of one.
Medicare does point out that the Medicare population, almost all of whom are 65 and over, may not be a good indicator for the under-65 population. Medicare is willing to look at future data.
These are the sorts of dilemmas health insurers must wrestle with. No decision will make everyone happy.
Rationing or evidenced-based medicine? Depends on your point of view.