Three slices, i.e., Basal, Mid, and Apical slices, which correspond to clinically useful ASE segmentation are designated, and the positions of the three slices are tracked through at least one cardiac cycle by performing three-dimensional speckle tracking in the remaining time phases. Three C-mode projection images concerning the tracked positions are reconstructed. In addition, arbitrary myocardial wall motion parameters at the tracked positions are computed and displayed upon being superimposed on C-mode images or projected/displayed on a polar map. As a C-mode projection image method, one of the following techniques can be used detecting and projecting only movement components perpendicular to slices determined in an initial time phase, detecting and projecting average movement components of the respective walls, and tracking and projecting each myocardial position. The obtained C-mode images are simultaneously displayed together with markers indicating the positions of long-axis images and C-mode images.
