CCTA has its foundation in coronary calcium scoring, which provides a quantification and measurement of calcified coronary plaque. Numerous scientific publications have documented the relationship between coronary artery calcification (CAC), the extent of coronary atherosclerosis and the attendant risks of this disease process. The presence of CAC provides information that is additive to standard risk factors and predictive data regarding future cardiac events. CAC is not, however, specific to obstructive coronary disease. Hence the development of CCTA using multi-detector scanners, which have improved temporal and spatial resolution, allowing non-invasive coronary angiography. Since 1999, multi-detector scanners have increased from four to 64 detectors with 256-detector and flat panel devices on the horizon. This progressive evolution of scanners with higher resolution will make the technology more accessible to a larger patient population and allow its application to an increasing number of clinical scenarios.

Atherosclerotic vascular disease in general and coronary artery disease (CAD) in particular remain the leading cause of morbidity and mortality in the industrialized world. Early detection and treatment remain cornerstones of therapy.CCTA’s unique combination of high spatial and temporal resolution allows visualization of not only the coronary lumen but also atherosclerotic plaque and associated vessel stenosis. Furthermore, CCTA allows characterization of atherosclerotic plaque based upon tissue attenuation measured with CT Hounsfield units. Early studies suggest that plaque density as well as volume can be assessed with CCTA.

Numerous clinical studies have documented the accuracy of CCTA. Early systems using 4- and 16- detector scanners were accurate in excluding disease but were limited in their ability to quantify disease. This limitation was primarily the result of motion artifact secondary to prolonged scan time and cardiac movement. Despite this problem, early studies documented a sensitivity from 83% to 99%, a specificity between 93% and 98% and a negative predictive value (NPV) of 95–100% when compared with invasive coronary angiography. Current-generation 64-detector scanners have maintained the excellent negative predictive capacity and have improved upon the positive predictive value (PPV). Sixty-four-detector scanners improve spatial resolution with thinner collimation (0.5mm) and improve temporal resolution with faster gantry rotation (0.33 seconds), thereby providing greater detail of the coronary arteries with limited artifact from cardiac motion. Further developments in scanner technology have included additional detectors (up to 256) and the placement of a second detector array in a single gantry (dual-source CT), which reduces scan times and decreases temporal resolution.These advances will allow for accurate visualization of smaller caliber vessels at higher heart rates without attendant motion artifact. Reduced scan times translates to shorter breath hold, increased patient comfort, decreased need for betablockade, and improved throughput.