Stress Myocardial Perfusion Imaging with Multidetector CT

Computed tomographic (CT) coronary angiography is a well-established, noninvasive imaging modality for detection of coronary stenosis, but it has limited accuracy in demonstrating whether a coronary stenosis is hemodynamically significant. An additional functional test is often required because both anatomic and functional information is needed for guiding patient care. Recent developments in CT technology allow CT evaluation of myocardial perfusion during vasodilator stress, thereby providing information about myocardial ischemia. Investigators in several single-center studies have established the feasibility of performing stress myocardial perfusion CT imaging in small groups of patients and have shown that stress myocardial perfusion CT in combination with CT coronary angiography improved the diagnostic accuracy in comparison with CT coronary angiography alone. However, CT perfusion acquisition protocols must be optimized in terms of acquisition and reconstruction parameters, contrast material protocol injections, and radiation dose. Further research is needed to establish the clinical usefulness of this novel technique. The purpose of this review is to (a) provide an overview of the physiology of coronary circulation and myocardial perfusion; (b) describe the technical prerequisites, challenges, and mathematic modeling related to CT perfusion imaging; (c) note recent advances in CT scanners and CT perfusion protocols; and (d) discuss the interpretation of CT perfusion images. Finally, a review and summary of the current literature are provided, and future directions for research are discussed. (C) RSNA, 2014