Friedrich MG et al. (2008) The salvaged area at risk in reperfused acute myocardial infarction as visualized by cardiovascular magnetic resonance. J Am Coll Cardiol 51: 1581–1587

A multinational study has found that cardiovascular magnetic resonance imaging (CMR) can differentiate between reversible and irreversible cardiac damage after acute myocardial infarction, thereby permitting quantification of the salvaged area after reperfusion.

Friedrich et al. enrolled 92 patients with acute myocardial infarction and 18 healthy controls. The median time from symptom onset to reperfusion was 6 h, and CMR was carried out a median of 3 days after the occurrence of infarction. T2-weighted CMR was used to visualize myocardial edema, and contrast-enhanced ('late-enhancement') CMR was used to measure the area of tissue necrosis, with gadolinium DTPA as the contrast medium.

High T2 signal abnormality matched the location of late enhancement for all 92 patients; mean size of the high-T2 area—which represents salvageable myocardium—was, however, significantly larger than the necrotic late-enhancement area. The size difference between the high-T2 and late-enhancement areas correlated inversely with time between symptom onset and reperfusion. Although visual examination showed a localized high T2 signal in 2 of the 18 healthy volunteers, quantitative analysis was negative for any abnormality.

This study suggests that CMR can identify injured but viable myocardium in the area at risk after acute myocardial infarction. This information could be valuable in the management of patients with acute myocardial infarction and might provide a novel end point for clinical trials.