Radiation Exposure Reduction during Voiding Cystourethrography in a Pediatric Porcine Model of Vesicoureteral Reflux

Abstract

To compare grid-controlled variable-rate pulsed fluoroscopy (GCPFL) and continuous fluoroscopy (CFL) for the reduction of radiation exposure during voiding cystourethrography (VCUG) in a pediatric porcine model of vesicoureteral reflux. Institutional animal care and use committee approval was obtained. Vesicoureteral reflux was simulated in four pigs, and 48 VCUG studies were performed (24 with GCPFL, 24 with CFL). VCUG was performed at abdominal girths of 8-10 cm (group 1, simulates human newborn to 6-month-old infant), 12-13 cm (group 2, simulates 2-3-year-old child), and 15-17 cm (group 3, simulates 10-year-old child). An electronic device calculated total radiation exposure during fluoroscopy and image recording. With five-point ordinal scales, VCUG images were scored independently for anatomic conspicuity and overall diagnostic quality by two radiologists (radiologists A and B). An analysis of variance was used to compare radiation exposures and fluoroscopy times between GCPFL and CFL and to determine whether radiation exposure and fluoroscopy time were dependent on the pig's abdominal girth. The Pearson product-moment correlation coefficient was used to assess whether fluoroscopy time was correlated with radiation exposure. Anatomic conspicuity and diagnostic quality scores were compared by means of the Wilcoxon signed rank test. Results of analysis of variance revealed that GCPFL resulted in a significant reduction in total radiation exposure compared with CFL for each of the three groups (P < .05 for each comparison), and this reduction was most marked in the larger animals. There were no significant differences in diagnostic quality of the recorded VCUG images (P > .05). Anatomic conspicuity was not significantly different for groups 2 and 3, but there was a significantly higher score for GCPFL in group 1 for radiologist A (P = .04). By using GCPFL in the performance of VCUG in a pediatric porcine model of vesicoureteral reflux, total radiation exposure can be reduced by a factor of 4.6-7.5 lower than with CFL, and diagnostic-quality images can be obtained.