Transthoracic and transesophageal echocardiograms allow excellent visualization of ventricular function and intracardiac structures. This recruitment of function may be detected by echocardiography. A significant limitation of echocardiography is its dependency on satisfactory acoustic images and operator variability. Since its development over 20 years ago, positron emission tomography has managed to enter the realm of clinical medicine. The development of new imaging systems, analysis and metabolic tracers have broadened the application of PET imaging.
PET imaging offers several benefits over other nuclear imaging modalities.
Cardiac PET allows the non-invasive quantification of regional functional processes such as myocardial blood flow, glucose utilization, oxidative metabolism, fatty acid metabolism, tissue hypoxia, and adrenergic and cholinergic innervation. Currently, the two major uses of cardiac PET are for the detection of coronary artery disease and the determination of myocardial viability. Ischemic but still viable myocardium will demonstrate decreased blood flow but will continue utilizing glucose as an energy substrate. When Rubidium-82 perfusion imaging is combined with FDG imaging an overall picture of blood supply and viable regions can be formed. Short axis FDg viability study demonstrates no uptake of activity in inferior wall matching the perfusion study.