Accuracy of subjective vesicoureteral reflux timing assessment: supporting new voiding cystourethrogram guidelines

Update on imaging recommendations in paediatric uroradiology: the European Society of Paediatric Radiology workgroup session on voiding cystourethrography

Voiding cystourethrography (VCUG) is a fluoroscopic technique that allows the assessment of the urinary tract, including the urethra, bladder, and-if vesicoureteral reflux (VUR) is present-the ureters and the pelvicalyceal systems. The technique also allows for the assessment of bladder filling and emptying, providing information on anatomical and functional aspects. VCUG is, together with contrast-enhanced voiding urosonography (VUS), still the gold standard test to diagnose VUR and it is one of the most performed fluoroscopic examinations in pediatric radiology departments. VCUG is also considered a follow-up examination after urinary tract surgery, and one of the most sensitive techniques for studying anatomy of the lower genitourinary tract in suspected anatomical malformations. The international reflux study in 1985 published the first reflux-protocol and graded VUR into five classes; over the following years, other papers have been published on this topic. In 2008, the European Society of Paediatric Radiology (ESPR) Uroradiology Task Force published the first proposed VCUG Guidelines with internal scientific society agreement. The purpose of our work is to create a detailed overview of VCUG indications, procedural recommendations, and to provide a structured final report, with the aim of updating the 2008 VCUG paper proposed by the European Society of Paediatric Radiology (ESPR). We have also compared VCUG with contrast-enhanced VUS as an emergent alternative. As a result of this work, the ESPR Urogenital Task Force strongly recommends the use of contrast-enhanced VUS as a non-radiating imaging technique whenever indicated and possible.

Standardized protocol for voiding cystourethrogram: Are recommendations being followed?

BACKGROUND

Voiding cystourethrogram (VCUG) images the urethra and bladder during filling and emptying, as well as ureters and kidneys when vesicoureteral reflux (VUR) is present, providing detailed information about both anatomical and functional status of the urinary tract. Given the importance of information obtained, and the varying quality depending on VCUG technique and radiology reporting, the American Academy of Pediatrics Sections on Urology and Radiology published a joint standardized VCUG protocol in 2016.

OBJECTIVE

We compared VCUG reports from multiple institutions before and after publication of the protocol to determine adherence to recommendations.

STUDY DESIGN

VCUG reports generated during two separate time periods were assessed - before and after publication - to evaluate impact of the protocol. Adherence to the reporting template was evaluated. Studies performed on patients >18 years of age and those obtained for trauma evaluation were excluded from study.

RESULTS

A total of 3121 VCUG reports were analyzed, 989 (31.7%) were generated before and 2132 (68.3%) after protocol publication. Comparing cohorts, there was no difference in gender (62.6% female versus 61.4%; p = 0.53) though children in the post-cohort were slightly older (3.34 ± 3.82 versus 3.68 ± 4.19 years; p = 0.03). A significant increase in scout image reporting (91.5%) and cyclic studies (20.5%) were observed in the post-cohort, in comparison to 79.2% and 13.1%, respectively, in the pre-protocol cohort (p < 0.001) [Figure]. Measured PVR and recorded infused volume actually decreased between study periods (84.7% vs 72.8% and 97.2% vs 91.5%, p < 0.001). There was no statistically significant difference between VUR grade reporting (99.4 vs 98.5%, p = 0.25). Recorded volume in which reflux occurred increased between periods (0.6% vs 2.3%, p < 0.05), while reporting of filling vs voiding reflux decreased in the post-cohort (84.4% pre-vs 77.4% post-protocol, p < 0.008).

DISCUSSION

The 2016 VCUG protocol recommended inclusion of various data points, however the volume at which reflux occurs remained vastly underreported. Timing of reflux has been shown to predict likelihood of spontaneous resolution and risk of breakthrough urinary tract infection; thus, its omission may limit the information used to counsel families and provide individualized care.

CONCLUSION

Despite consensus on standard VCUG protocol to best perform and record data, reports remain inconsistent. While VUR grade is routinely reported, other important anatomic and functional findings which are known to impact resolution and breakthrough urinary tract infection rates, such as volume at which reflux occurs, are consistently underreported.