Nuclear Cardiology

Nuclear cardiology is generally considered a clinical phenomenon of the past four decades. However, the field has its roots in earlier times. This chapter focuses on these historical roots as they have evolved into the present era. The initial application of radioisotopes to cardiac studies occurred in the mid-1920s. Ventricular function was evaluated in the 1960s and 1970s by first pass and equilibrium techniques. Myocardial stress perfusion imaging was first performed using potassium-43 and exercise in 1973. Stress imaging rapidly evolved thereafter with new tracers (thallium-201 and technetium-labeled agents) and from planar to SPECT approaches. Perfusion imaging rapidly proved its value diagnostically and in assessing prognosis. Infarct imaging reached its peak use in the 1970s but is now no longer employed. Advances in hybrid imaging, combining CT with radionuclide imaging has recently allowed attenuation correction as well as providing the combination of anatomic and physiologic data. PET myocardial perfusion studies have recently become a standard approach for evaluating perfusion, absolute coronary blood flow and coronary reserve. PET FDG studies of cardiac sarcoidosis have recently been established as a new approach for defining myocardial inflammation. New SPECT systems provide high sensitivity, high resolution studies, allowing for radiation dose reduction and high quality imaging studies.