While it is not without risks, optical colonoscopy (OC) has long been the gold standard for colorectal cancer screening. The problem is that most Americans fail to undergo screening as recommended, probably because it is an invasive procedure that requires what many consider to be an onerous preparation regimen designed to cleanse the colon. For that precise reason, there is growing interest in CT colonography (CTC) as an alternative screening procedure that could potentially encourage many more people to undergo colorectal screening, and ultimately save lives.