Myocardial area at risk after ST-elevation myocardial infarction measured with the late gadolinium enhancement after scar remodeling and T2-weighted cardiac magnetic resonance imaging

To evaluate the myocardial area at risk (AAR) measured by the endocardial surface area (ESA) method on late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) when applied after scar remodeling (3 months after index infarction) compared to T2-weighted CMR imaging. One hundred and sixty nine patients with ST-elevation myocardial infarction, treated with primary percutaneous coronary intervention, underwent one CMR within 1 week after index treatment to determine the AAR with T2-weighted imaging and a second scan 3 months after to measure AAR with the ESA method. There was a moderate correlation between the two methods (r = 0.86; P < 0.001). The AAR was significantly higher measured with T2-weighted imaging than with the ESA methods (32 ± 11% of left ventricle (LV) vs. 26 ± 10%LV; P < 0.001). The mean difference was 6 ± 6%LV. Furthermore, the mean difference between the two methods was statistical higher in the patients with myocardial salvage index ≥0.90 than in the remaining patients (9 ± 8%LV vs. 6 ± 5%LV; P = 0.02). The ESA method performed after scar remodeling (3 months following STEMI) yields significantly lower AAR′s and myocardial salvage indices compared to the T2-weighted method. Therefore, T2-weighted CMR plus LGE is the method of choice to assess AAR and myocardial salvage index using CMR. However, the ESA method is an easy and valid method for determining AAR, which can be used in settings where T2-weighted imaging has not been obtained in the acute phase.