The usefulness of positron emission tomography

The evaluation of myocardial blood flow, especially in conjunction with studying either residual oxidative metabolism or glucose uptake, accurately identifies potentially reversible myocardial dysfunction. It also reliably distinguishes between an irreversible and reversible impairment in left ventricular wall motion. The presence of metabolic abnormalities as evidence of reversible dysfunction is associated with an increased risk for cardiac-related morbidity and death and thus identifies patients likely to gain most from surgical revascularization. Restoration of blood flow to reversibly dysfunctional myocardium that occupies at least 15% to 20% of the left ventricle reduces long-term mortality, improves congestive heart failure-related symptoms, and enhances left ventricular performance. Blood flow-metabolism imaging can be especially useful for patients with ischemic cardiomyopathy who are evaluated for cardiac transplantation. A PET-driven management algorithm aids in identifying those patients likely to benefit most from revascularization. Such identification can reduce significantly the cost of managing patients with end-stage coronary artery disease.