Metabolic cardiac imaging with [18F]-fluorodeoxyglucose (FDG) and positron emission tomography (PET) has been established as the diagnostic and prognostic gold standard. This is usually combined with a perfusion scan, as the classical diagnostic finding is the so-called flow–metabolism mismatch (low flow, preserved FDG uptake). Hybrid PET/computed tomography (CT) and single photon emission computed tomography (SPECT)/CT scanners add a new dimension to non invasive diagnostic procedures, as they allow simultaneous assessment of function (metabolism or perfusion) and coronary anatomy. Hybrid imaging can integrate metabolic FDG information with CT-visualized
anatomy, thus providing a new approach for diagnosing dysfunctional but viable myocardium by directly visualizing information on viability in segments subtended by severely stenosed/occluded coronary vessels.