SPECT Myocardial Perfusion Imaging: Poststress, End Systolic Images and the Ongoing Effort to Improve Diagnostic Accuracy.

It is fair to state that interpretation of SPECT myocardial perfusion images, as with most scintigraphic studies, reflects a mixture of art and science. Increasingly, efforts have been, and are being, made to improve the diagnostic accuracy of SPECT myocardial perfusion imaging (MPI) by enhancing image quality while at the same time reducing radiation burden, via the scientific, technologic approach. Examples include the introduction of solid-state cadmium zinc telluride detectors, cardiac-optimized collimation, and improved image reconstruction software designed to mitigate factors such a patient motion, photon scatter, and tissue attenuation as well as spatial resolution and partial-volume effect (1,2). Although these image-quality issues are much more pronounced in SPECT than in PET, PET is not immune. However, given the fundamental physics involved, PET imaging is better able to correct such errors, a fact previously noted by this group (3) and many others (4–6). It also has been appreciated for some time that apparent tracer distribution in single-photon myocardial perfusion