Fig. 1

Longitudinal view of the right kidney demonstrating moderate hydronephrosis in a 5-year-old boy with a 5-mm proximal ureter calculus.

Fig. 2

Longitudinal view of the right kidney demonstrating moderate hydronephrosis in a 17-year-old adolescent girl with a 2-mm mid-ureter calculus. The application of color Doppler allows differentiation of the dilated collecting system from renal hilar vasculature.

Fig. 3

Longitudinal view of the bladder in a 17-year-old adolescent girl demonstrating a visible calculus (arrow) at the right ureterovesicle junction, with acoustic shadowing deep to the stone.

Fig. 4

Transverse view of the bladder demonstrating twinkling artifact from a 1.5-mm calculus at the right ureterovesicle junction in a 10-year-old boy. This artifact of alternating color Doppler signal arises from the acoustically reflective surface of a calculus.

Fig. 5

Transverse view of the bladder demonstrating bladder bulge (arrow) at the level of the right utererovesicle junction in the same patient as in Fig. 3 .

Fig. 6

Transverse view of the bladder demonstrating a right ureteral jet. Observation of this imaging plane over the course of 10 minutes did not demonstrate a left ureteral jet, consistent with complete left ureter obstruction. This 9-year-old boy with ulcerative colitis had a 7-mm calculus in the proximal left ureter.