If coronary computed tomographic angiography (CTA) were compared with invasive angiography on the basis of temporal and spatial resolution alone, coronary CTA would be forced to concede defeat. Whereas invasive angiography has a temporal resolution of just 33 msec, CTA has a temporal resolution of approximately 175 msec. Invasive angiography is superior to 16- and 64-slice coronary CTA in spatial resolution as well: 0.20 to 0.25 mm versus 0.4 to 0.8 mm, respectively.
CTA is capable of much more than "lumenography," however, and its unique strengths are providing new insight into the evaluation of patients with suspected coronary artery disease (CAD). This article will discuss the role of coronary CTA in the evaluation of coronary plaque—not only obstructive plaque (Figure 1) but also nonobstructive plaque and plaque composition. Underscoring the discussion will be the concept of clinically relevant plaque and the potential of coronary CTA to guide diagnosis, treatment, and prognostication in a way that is meaningful to patients and physicians.
