Imaging techniques for coronary artery disease: current status and future directions

We review the current status and future directions of sestamibi single-photon emission-computed tomography (SPECT), position emission tomography (PET), magnetic resonance imaging (MRI), and contrast perfusion echocardiography (CPE) for coronary artery disease evaluation. Diagnostic accuracy and adjunctive assessment of ventricular function make sestamibi SPECT the currently favored stress imaging radioisotope technique. Tissue attenuation correction will likely enhance these capabilities of SPECT in the near future. PET potentially offers valuable diagnostic information, as it may be a superior technique where body habitus limits cardiac imaging. We project that it is unlikely to become routinely used for cardiac imaging because of improvements in routine radionuclide imaging and the lack of evidence that the small resolution gain with PET is of importance, given the much larger cost. Cardiac MRI for assessing cardiac function, perfusion, and coronary angiography is an exciting new modality at an early stage of development. The possible comprehensive nature of MRI for coronary artery disease evaluation, potential cost savings related to utilization of a single, noninvasive test, and availability of scanning equipment in current community settings all project an important role for MRI in the future. Contrast perfusion echocardiography is also a relatively new and untested imaging modality which offers great future promise. The recent development of intravenous contrast agents and the current widespread availability of echocardiographic expertise and equipment throughout the country suggest that the speed of development as well as the dispersion of technologic advances will be rapid. We project that these techniques will play important roles in future coronary artery disease testing and will result in improved diagnostic efficacy and possibly cost utility.