Positive (PPV) and negative predictive values (NPV) for different tracer uptake thresholds for sestamibi (MIBI) and fluorodeoxyglucose (FDG) uptake. Positive predictive value indicates improvement of function ≥1 SD of regions with tracer uptake above the threshold; negative predictive value indicates lack of improvement in regions with uptake equal to or below the threshold. Regions (n = 59) with reduced wall motion (less than or equal to −1 SD) at baseline and successful revascularization are analyzed. Note that the positive predictive value for increasing fluorodeoxyglucose values increases, indicating the effects of perfusion/metabolism mismatches. The high negative predictive value of fluorodeoxyglucose for uptake values between 50% and 80% is influenced by scar or intermediate regions with no elevated glucose metabolism. In contrast, sestamibi shows decreasing positive predictive value with increasing baseline values, indicating that revascularization of dysfunctioning regions without evidence for reduced rest perfusion does not result in substantial functional improvement.