Accuracy of myocardial viability imaging by cardiac MRI and PET depending on left ventricular function

Table 1 Scoring system for evaluation of myocardial viability in cardiac magnetic resonance imaging and positron emission tomography

Score	CMR	PET
1	No enhancement	Normal FDG uptake
2	Enhancement < 50% of wall thickness	Reduced FDG uptake, ≥ 50% of maximum
3	Enhancement ≥ 50% of wall thickness	Reduced FDG uptake, < 50% of maximum
4	Transmural enhancement	No FDG uptake

Based on the data by Kim et al[22], score 1 and 2 represent viable myocardium, while score 3 and 4 are regarded as non-viable tissue (“scar”) in view of expected functional improvement after revascularization. Per definition, reduced or completely missing viability encompassed decreased or no FDG-uptake. CMR: Cardiac magnetic resonance imaging; PET: Positron emission tomography; FDG: Fluorodeoxyglucose.