Strain Rate Imaging Differentiates Transmural From Non-Transmural Myocardial Infarction: A Validation Study Using Delayed-Enhancement Magnetic Resonance Imaging Original Research Article

Objectives The aim of this study was to determine if strain rate imaging (SRI) correlates with the transmural extent of myocardial infarction (MI) measured by contrast-enhanced magnetic resonance imaging (Ce-MRI). Background Identification of the transmural extent of myocardial necrosis and degree of non-viability after acute MI is clinically important. Methods Tissue Doppler echocardiography with SRI and Ce-MRI were performed in 47 consecutive patients with a first acute MI between days 2 and 6 and compared to 60 age-matched healthy volunteers. Peak myocardial velocities and peak myocardial deformation strain rates were measured. Location and size of the infarct zone was confirmed by Ce-MRI using the delayed enhancement technique with a 16-segment model. Results Contrast-enhanced MRI identified transmural infarction in 21 patients, non-transmural infarction in 15 (mean transmurality of infarct 72.3 ± 10.6%), and another 11 patients with subendocardial infarction (<50% transmural extent of the left ventricular wall). Peak systolic strain rate (SRs) of the transmural infarction segments was significantly lower compared to normal myocardium or with non-transmural infarction segments (both p < 0.0005). A cutoff value of SRs >−0.59 s−1 detected a transmural infarction with high sensitivity (90.9%) and high specificity (96.4%), and −0.98 s−1 >SRs >−1.26 s−1 distinguished subendocardial infarction from normal myocardium with a sensitivity of 81.3% and a specificity of 83.3%. Conclusions Peak myocardial deformation by SRI can differentiate transmural from non-transmural MI, and it allows noninvasive determination of transmurality of the scar after MI and thereby the extent of non-viable myocardium.