Coronary Atherosclerosis Imaging by Coronary CT Angiography

Abstract

Coronary computed tomography angiography (CTA) provides high resolution, non-invasive visualization of the coronary arteries and coronary atherosclerosis. Recent technologic advances in coronary CTA image acquisition and reconstruction have dramatically reduced patient radiation exposure to relatively low levels while simultaneously improving image quality. Large-scale, multicenter studies have consistently demonstrated coronary CTA to be highly accurate compared to invasive coronary angiography for the detection of coronary artery disease (CAD), prompting the development of guidelines regarding its performance, interpretation and results reporting; as well as Appropriate Use Criteria to promote proper patient selection for testing. Accumulating data show that coronary CTA-based semiquantitative and quantitative measures of plaque characteristics, composition, and geometry have sufficient reproducibility and accuracy as compared to intravascular ultrasound, intravascular ultrasound with radiofrequency backscatter, optical coherence tomography and near-infrared spectroscopy. Beyond its role as a diagnostic test, the burden of coronary artery disease (CAD) visualized on coronary CTA (or absence thereof) ­provides powerful prognostic information, incremental to clinical risk factors and coronary artery calcium severity. Emerging data validating CT-based plaque characteristics such as the degree of remodeling (remodeling index), plaque volume and low plaque CT density may have incremental value for the prediction of adverse cardiovascular events. Similarly, the use of dual-energy imaging to better define plaque characteristics and CT perfusion imaging may prove to further enhance the clinical yield of coronary CTA. Ultimately, to realize the full potential of coronary CTA, studies are needed assessing the potential benefit of intensive preventative therapies that are differentially applied based on coronary CTA results, such as to further define the optimal treatment of advanced non-obstructive CAD or patients with potentially high-risk plaque features on coronary CTA.