Methodology for quantifying absolute myocardial perfusion with PET and SPECT.

Noninvasive quantitative measurement of myocardial perfusion has played an important role in cardiac research and also has potential applications in clinical imaging. Positron emission tomography (PET) methods for measuring absolute perfusion are well established, although the need for an on-site cyclotron has restricted its use to a limited number of centers. Single-photon emission CT (SPECT) also has potential for quantifying myocardial perfusion and has more widespread availability. In this article we review the basic principles of absolute myocardial perfusion quantification and the radiopharmaceuticals that are available for both PET and SPECT. We also examine the extent to which recent developments in instrumentation have increased the practicality of absolute perfusion quantification in PET and the potential for absolute quantification in SPECT.