Gated single-photon emission computed tomography. The present-day ''one-stop-shop'' for cardiac imaging.

Gated single-photon emission computed tomography (SPECT) is the current state-of-the-art approach to myocardial perfusion imaging. Initially, major emphasis was given to the improvement in diagnostic accuracy of myocardial perfusion imaging for the detection of coronary artery disease, because the evaluation of wall motion and thickening allows the recognition of attenuation artifacts and increases the observer's confidence. Different processing algorithms make possible to perform a reproducible and reliable assessment of left ventricular (LV) function, which has been extensively validated against various reference methods. Several articles report the additional value of functional data derived from gated SPECT to increase the accuracy of myocardial perfusion imaging in particular patient groups, such as women, to enhance the detection of multivessel coronary artery disease, and to permit the recognition of severe stenosis. An extensive literature indicates that gated SPECT allows a more accurate and reliable prognostic stratification of patients with known coronary artery disease. More recently, the peculiar contribution of gated SPECT in the assessment of myocardial viability has been demonstrated, with the possibility to evaluate in a single myocardial perfusion study the presence of preserved tracer uptake and the amount of contractile reserve through the acquisition of gated SPECT during inotropic stimulation with dobutamine. The most recent advance in the application of gated SPECT is the use of this technique for the reproducible assessment of LV functional changes, at follow-up or during inotropic stimulation, with perfusion data in the background. Various clinical settings, such as assessment of response to medical or resynchronization therapy in dilated or ischemic cardiomyopathy, prediction of outcome in chronic coronary artery disease with LV remodeling, evaluation of different treatment strategies in acute myocardial infarction, could take advantage from the unique combination of perfusion and functional data made possible by the use of gated SPECT. In conclusion, myocardial perfusion imaging with gated SPECT is a convincing reality in the field of cardiac imaging and has a still largely unexplored potential for a wider use in heart disease.