Myocardial perfusion imaging and multidetector computed tomographic coronary angiography: appropriate for all patients with suspected coronary artery disease?

摘要

Over the last 5 years, we have witnessed an impressive introduction of new imaging technology for the evaluation of patients with known or suspected coronary artery disease (CAD). The introduction of multidetector computed tomographic (CT) scanners with submillimeter spatial resolution and subsecond gantry rotations has revolutionized the field of cardiac imaging by making "direct" noninvasive imaging of the coronary arteries possible. The application of this technology in the form of CT coronary angiography (CTA) Results in an accurate test for excluding coronary atherosclerosis with a very high negative predictive value (>95%), especially when using 16- or 64-slice CT (1). Theuse of CTA also provides excellent diagnostic sensitivity for identifying stenoses in the proximal and middle segments (>1.5 mm in diameter) of the main coronary arteries. Unlike invasive coronary angiography, CTA not only assesses disease within the coronary lumen but also provides direct qualitative and quantitative information about non-obstructive atherosclerotic plaque burden and its composition. Thus, it is possible that CTA-based patient evaluation may provide more clinically relevant information upon which to base risk assessments compared with conventional "lumenography."Consequently, CTA is without a doubt a powerful noninvasive modality for evaluating and excluding CAD-with respect to both obstructive stenoses and atherosclerosis-and it will likely play an important role in the diagnosis of CAD. Before the widespread clinical application of CTA to daily practice, however, major questions must be answered. For example, where in a testing algorithm will this test fit?Does it replace exercise treadmill testing, stress myocardial perfusion imaging (MPI), both, or neither? Who are appropriate candidates for CTA? To this end, defining the role of CTA in a patient testing algorithm awaits the Results of investigations defining the relative roles and capabilities of CTA compared with conventional noninvasive testing.