Abstract: The purpose of percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) is to save dying myocardium as much as possible. The amount of myocardial salvage (MS) is closely related to whether the patients benefit from the PCI. MS is of great value for PCI efficacy evaluation and prognosis. To assess MS, the initial myocardial area at risk (AAR) before PCI and the final infarction size (FIS) after PCI should be determined, and the difference between the two is called MS. AAR and FIS can be quantified by double ⁹⁹Tc^m-methoxy-isobutyl-isonitrile gated SPECT myocardial perfusion imaging (GSMPI) on emergency admission and after PCI, respectively. The results are objective and accurate, and its clinical value has been confirmed in early large sample studies. However, emergency GSMPI has many limitations that make AAR difficult to obtain. In recent years, some scholars proposed that the only one GSMPI method early after PCI could replace double imaging method for MS evaluation, which significantly improved the feasibility and expanded the application extent of GSMPI in the diagnosis and treatment of AMI, and provided supplementary information for risk stratification in patients with AMI. The principle, application value, advantages and development prospect of the new method for evaluating MS in AMI patients are reviewed by authors.