Single-Photon Emission Computed Tomography Perfusion Imaging

Abstract

In business and legal transactions, a warranty is an assurance by one party to the other party that certain facts or conditions are true or will happen; the other party is permitted to rely on that assurance and seek some type of remedy if it is not true or followed. http://en.wikipedia.org/wiki/Warranty As single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) has reached scientific and clinical maturity, we have grown to expect that the results of this test when negative, reliably predicts an excellent patient outcome. Typically, less than 1% of patients with a normal study will have a “hard” cardiac event, defined as myocardial infarction or cardiac death, but that 1% can be shortened or lengthened based on the presence of coronary artery disease (CAD), cardiac symptoms, age, sex, the need for pharmacological stress, and coronary risk factors such as diabetes mellitus. The time variability was assessed by Hachamovitch et al,1 and termed the “warranty period” for a normal SPECT MPI, defined the time to 1% risk of a cardiac event per year. The study published in this issue of Circulation: Cardiovascular Imaging by Carryer et al2 sought to explore the timing of follow-up SPECT study after a normal initial study and its prediction of cardiac events during a 5-year follow-up. They identified 3010 patients with a normal SPECT …