on January 26, 2009
Published online before print January 26, 2009, doi: 10.1161/CIRCIMAGING.108.789032
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Original Article |
Strain-Encoded Magnetic Resonance Imaging for Evaluation of Left Ventricular Function and Transmurality in Acute Myocardial Infarction
1 University Hospital Heidelberg, Heidelberg, Germany;
2 University Hospital Aachen, Aachen, Germany;
3 Johns Hopkins University, Baltimore, Maryland
4 E-mail: mneizel{at}ukaachen.de
Background—Strain-encoded imaging (SENC) is a new technique for myocardial deformation analysis in cardiac magnetic resonance imaging (CMR). The aim of the study was therefore to evaluate whether myocardial deformation imaging performed by SENC allows for quantification of regional left ventricular function and is related to transmurality states of infarcted tissue in patients with acute myocardial infarction (AMI).
Methods and Results—CMR was performed in 38 patients with AMI 3±1 days after successful reperfusion using a clinical 1.5 Tesla MR-scanner. Ten healthy volunteers served as controls. SENC is a technique that directly measures peak circumferential strain from long-axis views and peak longitudinal strain from short axis views. Measurements were obtained for each segment in a modified 17 segment model. Wall motion and infarcted tissue were evaluated semi-quantitatively from SSFP cine sequences and contrast-enhanced-MR-images and were then related to myocardial strain. Comparison of peak circumferential strain assessed by SENC and MR-tagging was performed. In total, 456 segments were analysed. Peak circumferential and longitudinal strain calculated from SENC-images was significantly different in regions defined as normokinetic, hypokinetic or akinetic (p<0.001). A cut-off peak systolic circumferential strain value of -10% differentiated non-transmural from transmural infarcted myocardium with a sensitivity of 97% and a specificity of 94%. Strain-analysis of SENC and MR tagging correlated well (r=0.76) with narrow limits of agreement (-9.9-8.5%).
Conclusions—SENC provides rapid and objective quantification of regional myocardial function and allows discrimination between different transmurality states in patients with AMI.
Key Words: myocardial infarction • myocardial strain • strain-encoded magnetic resonance imaging • viability
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