with each direction scanned with a step size of 0.5 mm. The transmission ultrasound signal at every point was the average of 1000 sample waves consisting of 1000 points recorded over a 48.000 µs period with a delay of 49.000 µs upon the initial wave pulse. The peak frequency of the transducers was 0.5 MHz. The tone-burst pulser was set to 32 half-cycles.