title: Mild renal pelvic dilatation is not predictive of vesicoureteral reflux in children.
abstract: OBJECTIVE
  To determine if mild renal pelvic dilatation at renal ultrasound (RUS) is a reliable sign of vesicoureteral reflux (VUR) at voiding cystourethrogram (VCUG) in children.
  
  
  METHODS
  All patients less than 10 years of age who had RUS and VCUG on the same day during a 2-year period were identified in a computerized database. The appearance of the collecting system of each kidney was classified into two groups: group 0 - no dilatation (</= 2-mm anteroposterior diameter of the renal pelvis) and group 1 - 3 to 10-mm AP diameter of the renal pelvis without caliectasis. VUR at VCUG was graded using the International Reflux Study Committee system.
  
  
  RESULTS
  Four hundred fifty-five patients (76 boys; 379 girls) with 910 kidneys were included. VUR occurred in 268 kidneys in 174 patients. There were 820 group 0 kidneys and 90 group 1 kidneys. Kidneys classified as group 1 (25.0 % had reflux) were no more likely to have reflux than were kidneys with nondistended (group 0) collecting systems (31.2 % had reflux). There was no statistical difference in the rate of reflux in patients with group 1 renal pelvic distention (39.2 % refluxed) and a normal collecting system (33.3 % refluxed) (P = 0.365).
  
  
  CONCLUSIONS
  The frequency of vesicoureteral reflux in children with mild renal pelvic distention is not significantly different than in children with no distention. Therefore, mild dilatation of the renal pelvis should not be considered an indication for voiding cystourethrography.
authors.affiliation: Department of Radiology, Indiana University Medical Center, James Whitcomb Riley Hospital for Children, 702 Barnhill Drive, Indianapolis, IN 46202-5200, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Davey
authors.forename: J M
authors.initials: JM
authors.lastname: Zerin
authors.forename: C
authors.initials: C
authors.lastname: Reilly
authors.forename: W T
authors.initials: WT
authors.lastname: Ambrosius
mesh_terms: D002648:Child; D002675:Child, Preschool; D004108:Dilatation, Pathologic / Q000150:complications; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007682:Kidney Pelvis / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014463:Ultrasonography; D014718:Vesico-Ureteral Reflux / Q000150:complications / Q000175:diagnosis*