Efficacy of coronary CT angiography: where we are, where we are going, and where we want to be.

Over the decade since its earliest introduction, coronary CT angiography has spread rapidly, despite the fact that its validation base is smaller than that of alternative imaging examinations. Consensus statements have issued a call for improvement of coronary CT angiography's knowledge base. This article reviews recent progress in validating the efficacy of coronary CT angiography in the detection of coronary artery disease, with a focus on clinical decision making, management, and outcomes. We discuss the rationale for comparative effectiveness research and a framework for assessment of levels of efficacy. Comparison is made with radionuclide myocardial perfusion imaging, which serves as a model noninvasive examination. The potential roles of coronary CT angiography in screening, early triage, and as a gatekeeper for catheterization are discussed. Although few randomized controlled trials have been performed to date, we review the pivotal publications and mention ongoing and future efforts. Cardiovascular event rates provide the basis for estimating the success of potential study designs. The rigorous validation of coronary CT angiography may serve as a model for other noninvasive diagnostics.