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

PURPOSE

Acutely infarcted native T1 (native T1) and extracellular volume (ECV) 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, ECV, infarct size and LV global function, respectively. LV remodeling was evaluated as the change in LV end-diastolic volume index (△EDV) at follow-up scan compared with baseline.

RESULTS

In acute scan, 37 patients (66.07 %) had microvascular obstruction (MVO). The native T1 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, ECV 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 only correlated with △EDV in patients without MVO (r = 0.495, P = 0.031); while ECV was associated with △EDV in all patients (r = 0.665, P =  0.002; r = 0.506, P =  0.001; r = 0.570, P <  0.001). Furthermore, ECV was independently associated with LV remodeling in multivariable linear regression analysis (β = 0.490, P =  0.002).

CONCLUSION

As a promising parameter for early risk stratification after AMI, ECV is associated with LV remodeling during follow-up; while native T1 may be feasible when MVO is absent.