An ultrasound imaging apparatus (200, 600) may include at least one controller (210, 610) which may be configured to: acquire ultrasound data of an anatomical region-of-interest (ROI), the ultrasound data including at least two frames acquired at different times over an interval of time as a push force is applied to induce movement in the anatomical ROI； determine a correlation between at least two of the acquired frames and form corresponding correlation coefficients； generate a correlation coefficient (CC) map based upon the determined correlation information between the at least two frames； and distinguish fluid from tissue within the CC map based upon a comparison of the correlation coefficients with at least one threshold value.
