Abstract 2289: Speckle Tracking Is Accurate for Computing Cardiac Twist
Background: This study was conducted to test the accuracy of speckle tracking and tissue Doppler based motion-detecting methods for determining cardiac twist in a new dynamic heart model that contracts and expands while twisting in synchrony.
Methods: We developed a twist phantom using a variable speed motor to rotate ten freshly harvested pig hearts in a water bath. The hearts were connected to a pulsatile pump that delivered a calibrated stroke volume synchronized with twisting. Three different degrees of twist (15, 30, 45) were studied. 2D B-mode and tissue Doppler short axis views were acquired with a 10MHz probe at frame rates of >100 fps on a GE Vivid 7 system. The image data was analyzed offline in EchoPac for computation of twist using tissue Doppler and a speckle tracking based method. LV twist by TDI was computed by integrating the velocities towards and away from the transducer at opposite septal and lateral regions after correcting for the changing LV radius.
Results: Both tissue Doppler and speckle tracking based methods yielded accurate results with these very high quality images. Twist at 15°, 30°, and 45° was estimated at 16.4 ± 1.6, 32.7 ± 1.7, and 59.2 ± 2.4 respectively by TDI and 12.6 ± 0.6, 32.3± 1.7, and 50.6 ± 1.2 for STE (r2=0.95 for TDI and 0.97 for STE).
Conclusions: Cardiac twist can be quantified noninvasively by imaging methods. The speckle tracking based method is more user friendly, less laborious than TDI, and has higher accuracy and reproducibility.