Characterization of infarcted myocardium by T1-mapping and its association with left ventricular remodeling

Purpose: Acutely infarcted native T1 (native T1(AI)) and extracellular volume (ECVAI) could quantify myocardial injury after acute myocardial infarction (AMI). Therefore, we sought to further explore their association with left ventricular (LV) remodeling during follow-up. Methods: 56 ST-segment-elevation MI patients were prospectively recruited and completed acute and 3-month cardiac magnetic resonance scans. T1 mapping, late gadolinium enhancement and cine imaging were performed to measure native T1(AI), ECVAI, infarct size and LV global function, respectively. LV remodeling was evaluated as the change in LV end-diastolic volume index (Delta EDV) at follow-up scan compared with baseline. Results: In acute scan, 37 patients (66.07 %) had microvascular obstruction (MVO). The native T1(AI) did not significantly differ between patients with or without MVO (1482.0 +/- 80.6 ms vs. 1469.0 +/- 71.6 ms, P = 0.541). However, ECVAI in patients without MVO was lower than that in patients with MVO (49.60 +/- 8.57 % vs. 58.53 +/- 8.62 %, P = 0.001). The native T1(AI) only correlated with Delta EDV in patients without MVO (r(mvo-) = 0.495, P = 0.031); while ECVAI was associated with Delta EDV in all patients (r(mvo-) = 0.665, P = 0.002; r(mvo+) = 0.506, P = 0.001; r(all patients) = 0.570, P < 0.001). Furthermore, ECVAI was independently associated with LV remodeling in multivariable linear regression analysis (beta = 0.490, P = 0.002). Conclusion: As a promising parameter for early risk stratification after AMI, ECVAI is associated with LV remodeling during follow-up; while native T1(AI) may be feasible when MVO is absent.