Noninvasive plaque imaging using contrast-enhanced cardiac computed tomography

Recent technical advances in both multislice spiral computed tomography (MSCT) and electron-beam computed tomography (EBT) renewed the clinicians' interest in the potentials of CT-based, contrast-enhanced, noninvasive coronary angiography. Despite the fact that invasive, selective coronary angiography remains the "gold standard", cardiac CT lumenography permits visualization of flow-limiting coronary stenosis with a sensitivity and specificity of about 90%. The method is, nevertheless, limited by imaging artifacts which are due to extensive coronary calcifications, or, especially in the right coronary and circumflex artery, to rapid coronary motion. Moreover, the clinical value for the exclusion of obstructive coronary artery disease is not yet established, and further prospective studies are required. On the other hand, cardiac CT permits reliable estimation of coronary calcification and quantification of overall coronary plaque burden and thereby allows risk assessment to predict the individual cardiovascular risk. Diagnostic accuracy may be enhanced by combining assessment of calcified plaque burden and contrast imaging. The newer MSCT technology also allows for differentiation of coronary lesion configuration, especially of noncalcified plaques. However, very few data are currently available on this aspect, and the future clinical relevance of this promising technique remains to be proven. The purpose of this article is to describe the principles and potentials of contrast-enhanced coronary CT imaging and to summarize the practical limitations with the currently available scanning equipment.