Why Quantify Myocardial Perfusion?

New insights from major prospective cohort studies with cardiac nuclear imaging

For more than two decades, radionuclide imaging has prevailed as a cornerstone in the diagnosis and treatment of patients with cardiac disease. From this experience, large cohort studies have emerged that demonstrate the prognostic value of cardiac radionuclide imaging in a variety of patient groups and conditions. Myocardial perfusion imaging has accrued the most robust evidence for accurate and independent risk stratification over traditional clinical variables. In a variety of patient populations, the presence of myocardial ischemia is a strong predictor of cardiac events on follow-up. In patients with heart failure, smaller observations have similarly established the prognostic value of viability imaging and imaging of cardiac sympathetic activity. The present review provides a summary of recent cohort studies with radionuclide imaging and a critical appraisal of their clinical implications. Its purpose is to put the available evidence into a clinical context, analyze its potential impact on patient management and identify gaps in knowledge and unanswered questions to be addressed in future randomized trials.