Because it can accurately detect preserved glucose metabolism even in the hypoperfused or stunned myocardium, 18-FDG-PET is considered as the gold standard of myocardial viability assessment. In tako-tsubo cardiomyopathy, a presumed condition of stunning, absence of glucose metabolism however is not a marker of death. This sheds a critical light on 18-FDG-PET as a gold standard for viability.