title: Multi-institutional Study Comparing the Height of Contrast During Performance of Voiding Cystourethrogram in Children.
abstract: OBJECTIVE
  To assess the effect of contrast height during the voiding cystourethrogram (VCUG). The VCUG is the gold standard diagnostic test for vesicoureteral reflux (VUR). Variation in parameters may affect detection and grade of reflux.
  
  
  METHODS
  In a multicenter, prospective, nonrandomized, observational study, patients undergoing VCUG were selected. VCUG was performed per study protocol except for a change in contrast height. The initial fill was performed at 50 cm and the second at 100 cm. Data collected included presence and grade of VUR and volume filled. The actual bladder volume filled was normalized to the estimated bladder capacity (EBC) as a percentage. A Cohen's kappa coefficient of agreement was used to test for difference in the incidence of reflux and grade between contrast heights. A Wilcoxon signed-rank test was used for differences in the percent EBC filled between heights.
  
  
  RESULTS
  From May 2012 to November 2013, 184 patients were enrolled. Seventy-one patients (39%) exhibited VUR at 50 cm and 80 patients (43%) at 100 cm. The kappa coefficient of agreement between 50 cm and 100 cm showed substantial agreement, with no significant difference in VUR grade. The percent of EBC filled at each height was significantly different: %EBC filled at 50 cm: 101 ± 46 (range 9.2-228.3), and %EBC filled at 100 cm: 130 ± 56 (range 37.8-280.6) (P < .0001).
  
  
  CONCLUSIONS
  No significant difference was noted in the detection of VUR with different contrast heights. A significantly larger bladder volume was instilled at 100 cm.
authors.affiliation: Pediatric Urology, University of Oklahoma Health Science Center, Oklahoma City, OK. Electronic address: Dominic-Frimberger@ouhsc.edu.
authors.forename: Dominic
authors.initials: D
authors.lastname: Frimberger
authors.affiliation: Pediatric Urology, University of Iowa, Iowa City, IA.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Cooper
authors.affiliation: Pediatric Radiology, University of Oklahoma Health Science Center, Oklahoma City, OK.
authors.forename: Faridali
authors.initials: F
authors.lastname: Ramji
authors.affiliation: Pediatrics, University of Oklahoma Health Science Center, Oklahoma City, OK.
authors.forename: Christopher
authors.initials: C
authors.lastname: Aston
authors.affiliation: Pediatric Urology, University of Oklahoma Health Science Center, Oklahoma City, OK.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ramadan
authors.affiliation: Pediatric Urology, University of Iowa, Iowa City, IA.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Kieran
authors.affiliation: Pediatric Urology, University of Iowa, Iowa City, IA.
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Storm
authors.affiliation: Pediatric Urology, University of Iowa, Iowa City, IA.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Pediatric Urology, University of Oklahoma Health Science Center, Oklahoma City, OK.
authors.forename: Brad P
authors.initials: BP
authors.lastname: Kropp
authors.affiliation: Pediatric Urology, University of Oklahoma Health Science Center, Oklahoma City, OK.
authors.forename: Blake
authors.initials: B
authors.lastname: Palmer
mesh_terms: D002648:Child; D002675:Child, Preschool; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D011446:Prospective Studies; D014521:Urethra / Q000000981:diagnostic imaging*; D001743:Urinary Bladder / Q000000981:diagnostic imaging*; D014554:Urination; D014567:Urography / Q000379:methods*; D014718:Vesico-Ureteral Reflux / Q000000981:diagnostic imaging*
chemical_list: D003287:Contrast Media