Method for estimation of myocardial strain rate using effective position of correlation window

Abstract

Strain rate imaging is known as an effective method for evaluation of the regional heart function. Strain rate can be estimated by the velocity difference and the distance between regional 2 points. In the conventional method, the geometrical centers of correlation windows, which are used for velocity estimation, are referred to determine the distance between two points. However, echo amplitudes in a correlation window are non-uniform, and the contribution of each sampled data needs to be considered. In the present study, the effective position of the correlation window was determined as the gravity center weighted by echo amplitude. In a basic experiment, the strain rate distributions along the depth direction, which were obtained by the conventional and proposed methods, were compared. Using the proposed method, the fluctuation of the strain rate could be decreased to less than 0.1 (m/s)/m compared to that of the conventional method of about 0.3 (m/s)/s.