Prognostic value of thallium-201 myocardial perfusion imaging. A diagnostic tool comes of age.

D uring the past 10 years, the use of thallium201 myocardial perfusion imaging has undergone considerable expansion and evaluation. Originally conceived as a noninvasive diagnostic tool useful in determining the presence or absence of anatomical coronary artery disease,1-4 201T1 imaging has now been shown to have important prognostic value in a wide spectrum of patients with coronary artery disease.5-49 This prognostic value derives from the ability of 201T1 imaging to identify the presence and extent of jeopardized viable myocardium. After a brief background discussion, data are reviewed that concern the prognostic value of 201T1 imaging in three primary populations-1) patients presenting with known or suspected coronary artery disease, 2) post-myocardial infarction patients, and 3) patients undergoing noncardiac surgery. Data comparing the prognostic value of 201T1 predictors to other patient variables, including clinical, electrocardiographic, and angiographic variables, are discussed. Finally, the physiological basis of these observations are examined.