Test-retest methodological precision of global PET myocardial perfusion by serial rest or stress PET minutes apart is ±10%. Day-to-different-day biological plus methodological variability is ±21%, thereby establishing boundaries of variability on physiological severity to guide or follow coronary artery disease management. Maximum stress increases perfusion and coronary flow reserve, thereby reducing potentially falsely low values mimicking ischemia.

Since randomized coronary revascularization trials in stable CAD have shown no reduced MI or mortality, the threshold of quantitative myocardial perfusion severity was analyzed for association with reduced death, MI or stroke after revascularization within 90 days after PET. In a prospective long-term cohort of stable CAD, regional, artery specific, quantitative myocardial perfusion by positron emission tomography (PET), coronary revascularization within 90 days after PET and all cause death, myocardial infarction and stroke (DMS) at 9 years follow-up, mean 3.0 ± 2.3 years, were analyzed by multivariate Cox regression models and propensity analysis. For 3774 sequential rest-stress PET scans, regional, artery specific, severely reduced Coronary Flow Capacity (CFC) (CFR ≤ 1.27 and stress perfusion ≤ 0.83 cc/min/g) associated with 60% increased hazard ratio for major adverse cardiovascular events (MACE) and 30% increased hazard of DMS that was significantly reduced by 54% associated with revascularization within 90 days after PET ( = 0.0369), compared to moderate or mild CFC, CFR, other PET metrics or medical treatment alone. Depending on severity threshold for statistical certainty, up to 19% of this clinical cohort had CFC severity associated with reduced DMS after revascularization. Coronary Flow Capacity by PET provides objective, regional, artery specific, size-severity physiologic quantification of CAD severity associated with high risk of death, MI and stroke that is significantly reduced after revascularization within 90 days after PET, an association not seen for moderate to mild perfusion abnormalities or medical treatment alone.

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Rationale. We aimed to define the impact of variable arterial input function on myocardial perfusion severity that may misguide interventional decisions and relates to limited capacity of 3D PET for high-count arterial input function of standard bolus R-82.Methods. We used GE Discovery-ST 16 slice PET-CT, serial 2D and 3D acquisitions of variable Rb-82 dose in a dynamic circulating arterial function model, static resolution and uniformity phantoms, and in patients with dipyridamole stress to quantify per-pixel rest and stress ccÁmin 21 Ág 21 , CFR and CFC with (1) and (2) 10% simulated change in arterial input.Results. For intermediate, border zone severity of stress perfusion, CFR and CFC comprising 7% of 3987 cases, simulated arterial input variability of ± 10% may cause over or underestimation of perfusion severity altering interventional decisions. In phantom tests, current 3D PET has capacity for quantifying high activity of arterial input and high-count perpixel values of perfusion metrics per artery or branches.Conclusions. Accurate, reproducible arterial input function is essential for at least 7% of patients at thresholds of perfusion severity for optimally guiding interventions and providing high-activity regional per-pixel perfusion metrics by 3D PET for displaying complex quantitative perfusion readily understood (''owned'') by interventionalists to guide procedures. (J Nucl Cardiol 2020;27:397-409.) Key Words: Quantitative myocardial perfusion AE cardiac PET Electronic supplementary material The online version of this article (https://doi.

Background. PET quantitative myocardial perfusion requires correction for partial volume loss due to one-dimensional LV wall thickness smaller than scanner resolution. Methods. We aimed to assess accuracy of risk stratification for death, MI, or revascularization after PET using partial volume corrections derived from two-dimensional ACR and three-dimensional NEMA phantoms for 3987 diagnostic rest-stress perfusion PETs and 187 MACE events. NEMA, ACR, and Tree phantoms were imaged with Rb-82 or F-18 for sizedependent partial volume loss. Perfusion and Coronary Flow Capacity were recalculated using different ACR-and NEMA-derived partial volume corrections compared by Kolmogorov-Smirnov statistics to standard perfusion metrics with established correlations with MACE.