Mapping Myocardial Salvage Index by Extracellular Volume Fraction Are We There Yet?

In ST-segment–elevation myocardial infarction (STEMI) patients treated by primary percutaneous coronary intervention (PPCI), the myocardial salvage index (MSI) provides a more sensitive measure for assessing the efficacy of novel cardioprotective therapies, than an absolute reduction in myocardial infarct (MI) size. Knowledge of the MI size and the size of the area at risk (AAR) are prerequisites for measuring the MSI, and both may be obtained by cardiovascular magnetic resonance (CMR) in reperfused STEMI patients, with the MSI shown to predict clinical outcomes after PPCI.1 CMR is considered the gold standard imaging modality for quantifying MI size, and it can also delineate the edema-based AAR, with T2- and T1-mapping CMR emerging as the most robust techniques,2 although no consensus has yet been reached