2D myocardial strain assessment in the mouse: a comparison between a synthetic lateral phase approach and block-matching using computer simulation

Estimating myocardial strain in the mouse with clinical equipment remains difficult due to the high heart rate and the small size of the mouse heart. Measuring the strain component perpendicular to the ultrasound beam is especially challenging because of the lack of phase information in that direction and the large speckle width compared to the wall thickness. In this study, the performance of a Synthetic Lateral Phase (SLP) approach was contrasted to a standard and a regularized 2D Speckle Tracking (2D ST) algorithm using simulated data sets. SLP yielded higher rms errors for the lateral strain estimates than the regularized 2D ST (Lateral rms error: 0.087 ± 0.012 vs. 0.052 ± 0.010; p < 0.05). No significant difference was found between the standard 2D ST and SLP. For the axial strain estimates, SLP produced higher rms errors than the standard 2D ST (Axial rms error: 0.063 ± 0.012 vs. 0.040 ± 0.008; p < 0.05). 2D ST combined with geometric regularization showed thus to be the most accurate method.