Single-photon emission computed tomography for assessment of myocardial viability.

Left ventricular dysfunction in patients with chronic coronary artery disease may be a result of dysfunctional but viable myocardium due to myocardial hibernation. Coronary revascularisation may substantially improve regional and global left ventricular dysfunction and long-term survival if a substantial amount of dysfunctional but viable myocardium is present. Because coronary revascularisation, by percutaneous coronary intervention or coronary bypass surgery, is associated with an increased periprocedural risk in patients with severe left ventricular dysfunction, careful preprocedural selection is needed. Assessment of myocardial viability with SPECT may facilitate clinical decision making and should be considered in patients with ischaemic left ventricular dysfunction who are eligible for coronary revascularisation. The most frequently used SPECT protocols use thallium-201 (201Tl) rest-redistribution, technetium-99m (99mTc) labelled viability tracers, or 18F-fluorodeoxyglucose (FDG) for assessment of myocardial glucose metabolism. Approximately 50% of the patients with ischaemic left ventricular dysfunction have a substantial amount of dysfunctional but viable myocardium on SPECT and should be considered for coronary revascularisation. The absence of myocardial viability can help to identify patients who will not benefit from high-risk percutaneous coronary interventions or surgery.