Improved High Frame Rate Speckle Tracking for Echocardiography

摘要

High frame rate (HFR) speckle tracking echocardiography (STE) assesses myocardial function by quantifying motion and deformation at high temporal resolution. Our lab recently proposed a two-step HFR STE methodology based on 1-D cross-correlation [1]. Even if it was proved to be accurate for a global assessment of the mid-wall myocardial motion, an impaired sensitivity to motion and lower feasibilities for the apical regions gave higher errors. Thus, the aim of this study was to improve the speckle tracking algorithm by improving the tracking quality in the apical region specifically while preserving tracking quality on the other segments as well as picking up movement transmurally, i.e. the endocardial, mid-wall and epicardial motion. Hereto, the original algorithm was modified by improving robustness and accuracy of the lateral motion estimation. Simulation results showed that the proposed changes resulted in a significantly lower error in the estimation of the global longitudinal strain (GLS). Moreover, these improvements were mostly visible in the apical region (e.g. strain error 4.64 ± 2.65% vs 1.19 ± 0.71% for the septum) and prioritized the local movements resulting in lower error ranges between contours ([0.2-0.46]% vs [0.33-1.66]%). Finally, for a qualitative comparison, a preliminary in vivo acquisition was performed.