AUTOMATED CONTOUR TRACKING FOR MYOCARDIAL ELASTOGRAPHY IN VIVO

Using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc.) and a retrospective ECG-gating technique, an extremely high frame-rate (up to 8 kHz) was previously shown achievable for full-view (12-mmtimes12-mm) myocardial elastography. In-vivo experiments were performed in anesthetized normal and infarcted mice. In this paper, myocardial contour was manually initialized in the first frame of the cine-loop and automatically tracked over the entire cardiac cycle, which correctly determined the region of interest (ROI) for better interpretation. The end-systolic cumulative displacement and strain showed that motion and deformation in the infarcted myocardium were significantly reduced, and that the infarcted region underwent thinning, rather than thickening, during systole. In conclusion, high frame rate, full-view myocardial elastography with automated contour tracking could provide regional strain information of the left ventricle throughout an entire cardiac cycle, and characterize normal as well as detect abnormal myocardial function, such as an infarction.