A multifunctional CT technology: Reality or illusion for patient risk assessment?

Abstract

A high-speed, multi-slice coronary computed tomography (CT) imaging has emerged as a promising or clinically available multifunctional technique for the assessment of myocardial ischemia, viability, ischemia-induced cardiac dysfunction, and coronary atherosclerotic alterations in patients with suspected or known coronary artery disease. Despite several technical issues remain to be resolved, cardiac CT imaging will have a reality as a multifunctional modality for guiding physicians in better decision-making for favorable clinical outcomes in patients with suspected coronary artery disease, provided that this imaging technology can contribute to characterization and localization of high-risk coronary atherosclerosis in combination with the quantitative evaluation of functional myocardial ischemia.Key Words: Myocardial ischemia AE stree myocardial perfusion imaging AE coronary artery disease AE cardiac CT See related article, pp. 1253-1262Several non-invasive modalities have emerged as promising or clinically available multifunctional techniques for the assessment of myocardial ischemia, ischemic burden size, ischemia-induced left ventricular dysfunction, myocardial viability, and high-risk coronary plaque, all of which are definitively related to unfavorable clinical outcomes in patients with suspected or known coronary artery disease. Among them, recent remarkable advances in high-speed, multi-slice computed tomography (CT) in cardiac imaging enable to evaluate not only coronary arteriosclerosis, including luminal narrowing, vulnerable plaque, and atherosclerotic remodeling, but also functional ischemia by the measurement of coronary flow reserve with or without a vasodilator agent. A wide-spread use and easy access to coronary CT at cardiology practice contributes to identifying cryptogenic coronary arteriosclerosis and vulnerable coronary plaque. On the other hand, anatomical approach to coronary artery disease tends to overestimate coronary luminal narrowing, which is not necessarily the hallmark of significant coronary artery disease or future cardiac event risks, 1-3 and sometimes results in unnecessary or ineffective selection of invasive diagnostic or therapeutic strategy. [4][5][6][7][8][9][10] In this context, cardiac CT technology as a multifunctional modality is still challenging and in progress. In this issue of J Nucl Cardiol, van Rosendael et al 11 investigated the association between atherosclerotic coronary morphology and functional ischemia both of which were estimated on the same day using a sequential CT imaging protocol together with an adenosine stress approach in 84 of 115 consecutive patients with new onset chest pain referred from the outpatient clinic. Authors demonstrated a limited but positive correlation between CT angiographic stenosis and adenosine-induced CT perfusion abnormality. Besides the small, single-center study and the limited number of ischemic lesions, there are several issues to be recognized in this study before these results can be put into clinical perspective.