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

D uring the past 10 years, the use of thallium- 201 myocardial perfusion imaging has un- dergone considerable expansion and evalu- ation. 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 myocar- dium. 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, electrocar- diographic, and angiographic variables, are dis- cussed. Finally, the physiological basis of these ob- servations are examined.