“W-shaped” volume curve with gated myocardial perfusion single photon emission computed tomography

Technical Aspects and Errors of Triggering and Synchronization in Gated Single Photon Emission Computed Tomography Myocardial Perfusion Imaging

Gated imaging, as a technically demanding procedure, requires special attention and effort to fulfill the technical adequacy and accuracy of the study, based on the available standard guidelines. One of the essential requirements to be met by both technologists and physicians, in nuclear cardiology, is triggering and synchronization as a fundamental subject of gating. There are many sources of gating errors that produce imaging artifacts and, in some occasions, render the images uninterpretable or the quantitative analyses less accurate. Sufficient knowledge of recognition of these artifacts and understanding of their related mechanisms (from physical and technical perspectives) enable the technologists and physicians to promote their performance in daily practice. In this article, intended as a readily practical technical review for nuclear medicine practitioners, it is aimed to present the technical and computer aspects of triggering and synchronization as well as the related errors during imaging.

Gating error because of prominent T waves with ECG-gated myocardial SPECT

It was well known that with marked arrhythmias, gating errors may produce perfusion and wall motion abnormalities. In the present case, without any arrhythmias or perfusion defects, severe abnormalities of wall contraction and thickening were demonstrated because of prominent T waves. This gating error was easily corrected by changing guidance lead to increase the amplitude of the R wave and decrease that of the T wave.