New Technology for Noninvasive Evaluation of Coronary Artery Disease

Abstract

Cardiac computed tomography (CT) and positron emission tomography (PET) are emerging as powerful noninvasive imaging tools for the evaluation of atherosclerosis in patients with known or suspected coronary artery disease (CAD). Unlike invasive coronary angiography, CT coronary angiography (CTA) not only assesses disease within the coronary lumen but can also provide direct qualitative and quantitative information about nonobstructive atherosclerotic plaque burden within the vessel wall. Thus, it is possible that CTA-based patient evaluation may provide more clinically relevant information on which to base risk assessments compared with conventional “lumenography.” On the other hand, PET is rapidly growing as a powerful and efficient alternative to conventional single-photon emission CT (SPECT) imaging to evaluate regional myocardial perfusion and metabolism in patients with CAD. In addition, PET scanners are now being converted to hybrid PET/CT devices, which, in the setting of CAD, offer the potential for a comprehensive noninvasive cardiac evaluation of anatomy and function. This review will discuss current and potential future applications of cardiovascular CT, PET, and hybrid PET/CT, with a particular focus on ischemic heart disease. The information provided by noninvasive imaging generally falls into 1 of 3 categories: myocardial perfusion, left ventricular (LV) function, or coronary artery anatomy. The clinical utility, value, and role of a noninvasive modality are based on 2 test characteristics: What type of information is provided (eg, stress perfusion, stress and/or rest LV function, coronary anatomy), and what is the accuracy of the information provided. For example, SPECT and PET both provide stress and rest perfusion information, but the latter will be a superior clinical tool if the imaging data better represent the actual defect size and are subject to less artifact. The advantage of PET over SPECT will be further enhanced, as will be discussed later, if it provides additional clinically relevant information not …