Noninvasive imaging in acute coronary disease. A clinical perspective

Numerous highly complex and sensitive noninvasive imaging techniques have enhanced the care of patients with acute myocardial infarction. Optimum use requires specific objectives to be defined in advance, including a review of the potential impact of the test on subsequent decisions. An additional issue that is subject to scrutiny in the current climate of cost containment relates to the incremental value of a specific examination. The imaging modality to be used will partially depend on other issues, including accessibility, cost, and interindividual or institutional expertise with a particular technique. Major applications in noninvasive imaging in the acute coronary syndromes include the following: 1) diagnosis, including identification of associated diseases and contraindications for acute reperfusion; 2) evaluation and management of complications (mechanical and nonmechanical); 3) determination of prognosis (both early and late); 4) estimation of myocardial viability; 5) assessment of therapeutic efficacy; 6) investigational approaches, including 99mTc-sestamibi tomographic imaging, ultrafast cine computed tomographic scanning, and nuclear magnetic resonance imaging. Previous studies in the prethrombolytic era have documented the powerful impact of radionuclide stress testing on prognosis, but this needs to be reevaluated in the light of the changing current population undergoing stress testing. Preliminary data imply that the prognostic accuracy of stress testing after thrombolytic therapy is diminished. Moreover, the role of the open infarct-related artery in traditional estimates of prognosis (e.g., ejection fraction) requires further study. Noninvasive imaging has multiple applications in the diagnosis and management of patients with acute coronary disease, but the decision to use a specific technology in a particular circumstance mandates good clinical judgment and selectivity.