Abstract 3145: High-resolution, High Frame-rate Strain Imaging for Early Myocardial Infarction Detection
Background: Myocardial elastography ( Konofagou EE et al, Ultrasound Med. Biol. 2002; 28: 475–482) is a novel technique for noninvasively imaging regional myocardial function.
Methods: In vivo experiments were performed in anesthetized, nine normal and seven post-infarction (one day post-LAD ligation) mice using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc.). Radio-frequency signals and the associated electrocardiogram (ECG) were simultaneously acquired. Using an ECG triggering technique, an ultrafast frame rate of 8000 frames/s was achieved that resulted in high-quality strain estimation. The strains during the entire cardiac cycle were imaged using an elastographic technique.
Results: High-resolution strain images (elastograms) clearly depicted all cardiac events including left-ventricular (LV) contraction, LV relaxation, atrial contraction and isovolumic phase in both normal and infarcted mice. The strain images showed a mechanical contrast of up to 10 times (p = 0.02) between normal and infarcted myocardia. Preliminary statistical results from normal mice (n = 9; p = 0.01) and infarcted mice (n = 7; p = 0.02) showed the cumulative strains during systole were equal to 0.56 ± 0.13 and −0.04 ± 0.32, respectively (see Fig. 1⇓).
Conclusion: Myocardial elastography can provide strain information at both high temporal and spatial resolution, and is capable of accurately characterizing normal myocardial function as well as detecting and localizing early myocardial infarction in vivo.