20 Myocardial extracellular volume predicts functional recovery in acute myocardial infarction more accurately than threshold-based measures of late gadolinium enhancement transmural extent

Abstract

The transmural extent of late gadolinium enhancement (LGE) CMR predicts functional recovery in acute myocardial infarction (AMI). Automated methods are recommended 1 to define infarct extent on LGE imaging, such as ‘n-standard deviations’ (SD) and ‘full width at half maximum’ (FWHM). These define infarcted myocardium by signal intensity as compared to remote myocardium, which in turn depends on signal-to-noise and contrast. Individual variability in these parameters makes a single thresholding technique unlikely to be universally suitable. Extracellular volume (ECV) estimation by T1-mapping CMR is theoretically less affected by sequence and contrast variations. We compared infarct ECV with threshold-based measures of LGE transmural extent to predict contractile recovery in reperfused AMI. Consecutive patients with reperfused first ST-elevation AMI underwent acute (day 2) and convalescent (3 months) CMR. Cine imaging, modified Look-Locker inversion T1 mapping natively and 15 min post gadolinium-contrast administration and LGE imaging were performed. Five LGE thresholding techniques were compared: 2, 5 and 6 SD, FWHM and a histogram-based technique (Otsu). 2 The ability of acute infarct ECV to predict improvement in segmental wall motion was compared with these thresholding techniques. n = 35 (28(80%) male, age 57 ± 11 years). Infarct characteristics are shown in Table 1. ECV showed modest correlation with all threshold measures of LGE (r 2 = 0.16–0.31, p Acute infarct ECV outperforms threshold-based LGE transmural extent to predict segmental LV functional recovery in reperfused AMI. References Schulz-Menger J, et al . J Card Magn Reson 2013;15:35 Otsu N. IEEE Trans Sys Man Cyber. 1979;9:62–6