SPET in cardiology. Diagnosis, prognosis, and management of patients with coronary artery disease.

Stress myocardial perfusion imaging has been considered as a most valuable means for diagnosis and treatment strategy in patients with suspected and known coronary artery disease. (99m)Tc perfusion imaging agents provide excellent myocardial perfusion images. In addition, greater photon flux from the tracer permits simultaneous assessment of regional perfusion and function with use ECG-gated acquisition. Gated SPET imaging technique has a potential for higher diagnostic accuracy for diagnosis of coronary artery disease and assessment of the disease severity. In addition, radionuclide imaging plays an important role to differentiate reversible ischemic myocardium which may improve LV function after revascularization from irreversible scar in patients with history of myocardial infarction. While FDG-PET is considered as a most reliable means for myocardial assessment, SPET imaging has been widely used for the viability assessment, with gaining higher accuracy for predicting reversible ischemia. Recently a variety of new radiopharmaceutical agents have been introduced to probe myocardial function in vivo. [(123)I]BMIPP, a branched fatty acid analog, has been used for metabolic imaging using SPET. Less uptake of BMIPP than perfusion is often observed in the ischemic myocardium. Such a perfusion metabolic mismatch which seems to be similarly observed in FDG-PET is identified in the stunned or hibernating myocardium with regional dysfunction. Severe ischemia is identified as reduced BMIPP uptake at rest, suggesting its role as an ischemic memory imaging. These new techniques will provide insights into new pathological states in the ischemic heart disease and enable to select optimal treatment of these patients.