Back to 2014 Fall Congress Meeting Abstracts

INTRODUCTION AND OBJECTIVES: The gold standard for evaluating and diagnosing vesicoureteral reflux (VUR) is voiding cystourethrography (VCUG). No standards exist for testing parameters and institutional variation in these parameters may affect detection of reflux and impair comparison of results between institutions. The aim of this study is to assess the effect of contrast height on reflux detection.
METHODS: In a prospective, non-randomized, observational study at the University of Oklahoma (OU) and University of Iowa (UI), patients undergoing VCUG for routine analysis were selected. Indications for performing VCUG included febrile UTIs, pyelonephritis, hydronephrosis, or history of VUR. Inclusion criteria were male and female patients aged 1 to 10 years old without known genitourinary anomalies.
In this study, the VCUG was performed per protocol except for a change in contrast height. The initial fill was performed at a contrast height of 50cm above the patient, and the second fill at a contrast height of 100cm. Each filling was performed until void and the bladder was emptied between fillings.
Data collected included the volume filled with each filling phase and the estimated volume at reflux. Estimated bladder capacity (EBC) was calculated using the formula: (age + 2) × 30 mL. The actual bladder volume filled was compared to the estimated bladder capacity as a percentage (%EBC filled = [Volume filled divided by EBC] x 100). A Wilcoxon signed rank test was used to test for difference between VCUG contrast heights of 50cm and 100cm in overall reflux grade and %EBC filled.
RESULTS: From May 2012 through Nov 2013, 184 patients were enrolled in the study from OU and UI. All studies were interpreted by staff pediatric radiologists at our institution, and, if present, VUR was graded from 1 to 5 as defined by the International Reflux Study Committee.
Of these, 88 exhibited reflux at 50cm and 100 at 100cm. The Kappa coefficient of agreement between the 50cm and 100cm fills for presence of VUR showed substantial agreement and there was no significant difference in VUR grade.
The percent of estimated bladder capacity filled at each height was available on 122 patients of the OU cohort and was significantly different (p < 0.0001):
OU %EBC filled at 50cm: 101 ± 46 [range 9.2 - 228.3]
OU %EBC filled at 100cm: 130 ± 56 [range 37.8 - 280.6]
CONCLUSIONS: In this study, there is no significant difference in the detection of VUR with contrast heights of 50cm and 100cm. A significant difference was found in the average filled volume over expected bladder capacity at one institution.