Abstract 3050: Studies of Strain Mechanics for Detecting Right Ventricular Scarring
Background: The unique shape of the right ventricle (RV) offers a particular challenge for strain imaging. Speckle tracking is a newer method of computing strain without the angle dependency of tissue Doppler imaging (TDI). We sought to test and compare both methods in a modeled RV infarct.
Methods: We studied 5 freshly harvested pig hearts in a water bath for ultrasound imaging. A pulsatile pump was attached to a latex balloon inserted into the RV cavity, delivering 6 different calibrated stroke volumes (SV) (15 to 40 ml) at 60 beats/min. Hearts were scanned in short axis views with a 10S probe on a GE Vivid 7 Dimensions system at 2D frame rates of 80 –100fps for grey scale and TDI. After baseline imaging, we injected 1–2ml of gluteraldehyde into the RV free wall to produce myocardial stiffening. The study was then repeated at the same SVs. Images were exported to EchoPac PC for analysis of circumferential strain (CS) in the RV free wall by speckle tracking and Doppler based methods.
Results: At each SV, Doppler derived strain showed higher (8 –14.5%) strain values as compared to speckle tracking based strain. With increased SV, a corresponding increase in CS was detected by both methods but speckle tracking derived strain showed better correlation with SV (r=0.85) than Doppler derived strain (r=0.71). Both methods delineated myocardial damage but speckle tracking showed higher reproducibility (r=0.78) than the Doppler based method (r=0.61).
Conclusions: In our study, speckle tracking was a superior method to delineate altered RV wall mechanics.