Pediatric renal pelvic fullness: an ultrasonographic dilemma.

PURPOSE: We conducted a prospective study to define normal renal pelvic size in children.

MATERIALS AND

METHODS

Institutional Review Board approved consent was obtained to perform renal ultrasound during excretory urography (IVP) scheduled for medical management. Mean patient age (17 females, 11 males) was 5.2 years. Renal ultrasound was conducted concurrent with 10-minute IVP.

RESULTS

Fifty kidneys were imaged with 51 collecting systems. IVP defined 44 collecting systems as normal. Mean anteroposterior pelvic diameter on sonography for these 44 systems was 3.3 mm. One normal collecting system on IVP had a diameter greater than 10 mm on ultrasound (14 mm). No sonographic caliceal dilatation was seen in any kidney appearing normal on IVP. The 7 dilated systems on IVP had a mean ultrasound diameter of 17.1 mm. Two dilated collecting systems smaller than 10 mm in diameter on sonography had caliceal distention on ultrasound.

CONCLUSIONS

Normal renal pelvis threshold diameter was 10 mm in asymptomatic children. We recommend further evaluation in children with caliceal dilatation and/or dilatation of the anteroposterior renal pelvis greater than 10 mm. Using these criteria, no system appearing abnormal on IVP would have been missed.