Assessment of myocardial viability by cardiac magnetic resonance imaging

Before putting a patient with a weakened heart through bypass or stenting, there is a question worth answering: is the damaged muscle still alive enough to recover, or is it scar that no amount of restored blood flow will revive? This review argues that cardiac MRI answers that question better than the alternatives.

The technique at its center is late gadolinium enhancement, which lights up scar tissue directly. Where older viability tests infer the state of the muscle indirectly, MRI shows the scar’s extent and location, and from that predicts how likely contraction is to improve after revascularization. The authors make the case for it as a first-line viability test — safe, precise, and uniquely able to distinguish viable tissue from dead.

The clinical payoff is a sharper decision in ischemic cardiomyopathy: spare a patient a futile, risky procedure when the muscle won’t recover, or proceed with confidence when it will. The resistance comes from centers built around nuclear imaging — SPECT and PET — where cost, equipment, and retraining argue against a switch.

We rate the evidence moderate. It is a well-referenced review from a respected group, but a narrative one, summarizing rather than generating evidence. Its clinical significance is likewise moderate: genuinely useful where the viability question is live, but that is a fairly specific population, and MRI access remains limited in many settings.