Relationship of MRI-Determined Infarct Size and cTnI Measurements in Patients with ST-Elevation Myocardial Infarction

The extent of myocardial infarction (MI) is related to patient outcomes (1), and clinicians often wish to have a sense for this critical measure. Imaging methods, although accurate, have limited accessibility and high cost. Thus clinicians often use biomarkers to provide such an estimate. Measurement of cardiac troponin T (cTnT) at 96 h after onset of MI was observed to correlate with MRI-determined infarct size in both ST-elevation MI (STEMI) and non-STEMI (2). We tested the hypothesis that cardiac troponin I (cTnI), another myocardium-specific biomarker, would provide an equivalent estimation in the subset of STEMI patients previously described (2).The 28 patients with STEMI had sufficient sample remaining to allow for determination of cTnI (2). The characteristics of this group have previously been reported (2), but in brief the mean age (SD) was 56 (11) years, and 17.4% of patients were women. Mean (SD) body mass index was 26.46 (3.5) kg/m2, and 71.4% of patients were hypertensive, 64.3% were current smokers, 60.7% had hypercholesterolemia, and 14.3% had diabetes. Blood samples were available at admission and at 24, 48, …