Assessment of myocardial viability by cardiac MRI.

Left ventricular systolic dysfunction because of coronary artery disease is common, and ascertaining which patients will benefit from revascularization can be challenging. Viability testing is an accepted means by which to base this decision, with multiple noninvasive imaging modalities available for this purpose. This review aims to highlight the key role of cardiac magnetic resonance in myocardial viability assessment, with a focus on its unique strengths over other imaging modalities. Transmural extent of hyperenhancement with late gadolinium imaging has been shown to be greater acutely in ST elevation myocardial infarction patients undergoing primary percutaneous coronary intervention and regress at follow-up studies. An explanation for this reported phenomenon and an argument against redefining CMR viability criteria in the acute setting will be offered. Although not universally available, cardiac magnetic resonance is an exceptionally powerful and well tolerated imaging modality that should be considered when viability testing will influence patient management. Although observational outcomes data suggest a promising prognostic role for viability, randomized studies in this area are needed.