Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology
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Real-time myocardial contrast perfusion imaging (RTMCI) with echocardiography is a promising technique for evaluation of patients with known or suspected coronary artery disease. The technique is based on the utilization of small (<10 mum) microbubbles, which are capable of crossing the pulmonary circulation after intravenous injection. Unlike radioactive isotopes, which are taken actively or diffuse passively in the myocytes, myocardial contrast agents remain extracellularly in the capillaries and present a measure of the myocardial capillary blood volume and microvascular integrity. ⋯ Perfusion abnormalities were also shown to predict short-term cardiac events in patients presenting to the emergency department with chest pain and no ST-segment elevation. Refinement of imaging techniques is expected to improve the specificity of RTMCI, particularly in differentiating true perfusion defects from artifacts. This review will discuss the physiologic basis, methodology, clinical utility, and limitations of RTMCI in the assessment of patients with known or suspected coronary artery disease.