(a)
(b)
(c)
(d)
Figure 1: Subject 2: seven-year-old girl. (a) Filling the urinary bladder (white long arrows) with the contrast agent. (b) Urinary bladder (white long arrows) 2 minutes after removal of the catheter and two failed voiding attempts, beginning of microbubbles destruction. (c) Urine bladder (white long arrows) 5 minutes after removal of the catheter with visible areas of destructed microbubbles (short white arrows). (d) Urinary bladder (white long arrows) 6 minutes after removal of the catheter and multiple voiding attempts, with visible single echoes from not destroyed microbubbles (short white arrows).