Contrast-enhanced magnetic resonance imaging reveals early decrease of transmural extent of reperfused acute myocardial infarction

In patients with myocardial infarction infarct size and transmural extent are of high prognostic value for clinical outcome and recovery of contractile function of the affected myocardium either spontaneously or after revascularisation. Delayed contrast-enhancement magnetic resonance imaging (DCE-MRI) is a non-invasive imaging technique of high accuracy for determination of myocardial infarct size and transmural extent. As decisions whether revascularisation procedures are promising in patients with coronary artery disease are increasingly based on the transmural infarct extent assessed by DCE-MRI we sought to examine whether the timing of MRI after acute myocardial infarction would influence the transmural extent. We performed DCE-imaging on a clinical 1.5 T scanner in patients at day-1 and day-7 after reperfused STEMI. We assessed the total number of segments displaying DCE as well as differentiated by the transmural infarct extent. The total number of affected segments as well as the number of segments with only subendocardial DCE did not change between day-1 and day-7. In contrast, we observed a significant decrease of the number of segments with DCE of a parts per thousand yen75% transmurality and a significant increase of segments with DCE grade III (51%-75% transmurality). We conclude that the transmural infarct extent is not stable over the first days after STEMI which should be taken into account when assessing viability in clinical and research settings.