Figure 3

Data processing in the flow tracking software. (A) Echo image of the rotating phantom. (B) After tracing the circumference of the phantom (purple line), the software tracks speckles inside this area and displays the estimated flow by means of arrows (yellow) (in this specific figure a velocity of 20 cm/s was used). (C) In a further step, the software defines the biggest continuous area of vortical flow as “vortex” which is marked with a red or blue patch depending on the rotation direction. The white circle indicates the detected vortex center. Note that the patch is smaller than the phantom – see text for details. (D) Echo image of the string phantom (E) After tracing the circumference of the phantom (purple line), the software tracks speckles inside this area and displays the estimated flow by means of arrows (yellow) (in this specific figure also a velocity of 20 cm/s was used).