Role of computed tomography in the evaluation of acute chest pain.

Chest pain is common and the initial clinical presentation is often nonspecific. The emergency physician faces the challenge of correctly identifying those patients with a life-threatening cause of chest pain while avoiding unnecessary hospital admissions. Three important life-threatening causes of chest pain are aortic dissection, pulmonary embolism, and acute coronary syndrome. Simple clinical tools should be applied to exclude these diagnoses and avoid CT whenever possible. A normal serum d-dimer measurement can safely exclude pulmonary embolism and aortic dissection, although elevated d-dimer levels are common and nonspecific. Promising markers for early myocardial ischemia have been described and should be developed further. CT provides a first-line imaging tool for aortic dissection and pulmonary embolism based on its wide availability, speed, and high level of diagnostic performance. Improvements in CT scanner technology now enable in-depth data on the coronary arteries. Although angiographic information is limited in its relation to physiologic lesion significance, coronary CT is used to safely diagnose or exclude coronary disease as a source of chest pain in emergency department patients. "Triple rule-out" protocols designed to simultaneously assess the aorta, pulmonary arteries, and coronary arteries are a compromise between dedicated protocols for each diagnosis. The diagnostic value and appropriate clinical use of these protocols remain to be shown by randomized, controlled, outcomes-based trials.