Objectives: To investigate the performance of a delayed-enhancement (DE) sequence adapted for a 3-minute delay after bolus injection of a contrast media in cardiac magnetic resonance imaging (MRI) in acute reperfused myocardial infarction.
Materials and methods: Sixty-three patients with recent myocardial infarction underwent contrast-enhanced MRI. Sequences of first-pass (FP) perfusion imaging and DE imaging at 3 and 15 minutes were performed at the acute phase. Of these patients, 49 had a follow-up cardiac magnetic resonance examination. Infarct sizes were quantified by 2 experienced users with a 17-segment model at the acute phase (at FP and at 3- and 15-minute delay) and at the chronic phase (at 15 minutes because only fibrous areas hyperenhance late). Areas of hypoenhancement and hyperenhancement were also calculated. Results from the 3-minute imaging sequence at the acute phase were compared with the FP (taking into account dark signal areas), with the 15-minute DE imaging sequence results at the acute phase [taking into account dark signal and hyperenhanced (white plus dark signal) areas] and with the 15-minute DE imaging sequence from the chronic phase (taking into account hyperenhanced areas). Least squares regression and Bland-Altman plots were performed for the comparisons.
Results: For the evaluation of hyperenhancement, the comparison between imaging sequence results at 3 minutes versus 15-minute DE at the acute phase (respectively, at the chronic phase) shows a good correlation (r(2) = 0.941; respectively r(2) = 0.862, at the chronic phase) and the Bland-Altman plot indicates a good concordance (m =-0.43; SD = 2.69; respectively m = 2.76; SD = 3.92); For the evaluation of hypoenhancement, the comparison between imaging sequence results at 3 minutes versus FP (respectively, 15 minutes at the acute phase) also shows a good correlation (r(2) = 0.751; respectively r(2) = 0.71) and the Bland-Altman plot indicates a good concordance (m = -1.06; SD = 3.34; respectively m = 2.90; SD = 3.11). Finally, the interobserver study provides a very good kappa coefficient (kappa = 0.82), and good kappa coefficients from the intraobserver study (kappa1 = 0.78 and kappa2 = 0.86).
Conclusions: The use of a delayed contrast-enhanced sequence adapted for a 3-minute delay after the bolus injection has the potential to obtain quickly reliable information comparable with the perfusion delay at FP and reliable information from the infarct size at 15 minutes and at the chronic phase.