Contrast-enhanced voiding ultrasonography to detect intrarenal reflux in children: comparison with 99mTc-DMSA renal scans

Reduced kidney size and renal function of high-grade vesicoureteral reflux and intrarenal reflux in contrast-enhanced voiding urosonography

BACKGROUND

Vesicoureteral reflux (VUR) is a common pediatric urological condition associated with renal scarring, hypertension, and chronic kidney disease. Contrast-enhanced voiding urosonography (ceVUS) has emerged as a promising technique for diagnosing and evaluating VUR, with intrarenal reflux (IRR) often detected using this method. This study aimed to explore the relationship between different VUR grades and IRR on ceVUS, and assess the impact of VUR and IRR on kidney size and function.

METHODS

We reviewed all ceVUS studies from January 2019 to December 2023 conducted at West China Hospital, Sichuan University. Both video clips and digital images of the ceVUS examinations were recorded. A total of 220 uretero-renal units (URUs) of 110 children (67 males and 43 females) were included in this study.

RESULTS

Among the 220 URUs assessed, 134 were diagnosed with VUR, and 25 exhibited IRR, with IRR exclusively observed in patients with grade II VUR or higher. Upon age and sex matching, the severity of IRR showed a significant positive correlation with high-grade VUR (P < 0.001). Notably, patients with high-grade VUR and IRR displayed reduced kidney size compared to those without VUR or IRR (P < 0.05). Furthermore, patients with high-grade VUR and IRR had reduced DMSA renal function (P = 0.015, P = 0.012, respectively), and patients with high-grade VUR had more DMSA scars (P = 0.027), compared with those without VUR or IRR.

CONCLUSION

Our study highlights that on ceVUS, the IRR degree was associated with the high-grade VUR, along with reductions in kidney size and renal function in patients with high-grade VUR and IRR.

Value of contrast-enhanced sonography in the diagnosis of vesicoureteral reflux

BACKGROUND

Contrast-enhanced ultrasound of the urinary tract and bladder (ceVUS) is an alternative examination method to micturition cysturethrography (MCU/VCUG) for suspected vesicoureteral reflux (VUR) that is increasing in practice. The purpose of this review is to present the current value of ceVUS in the diagnosis.

METHOD

A systematic literature search was performed using the keywords "vesicoureteral reflux", "ceVUS", "VCUG" of the databases MEDLINE and Cochrane Library as well as a review of current German, European, and American guidelines on this topic. In addition, recommendations for action in clinical practice were developed.

CONCLUSION

ceVUS is a quick-to-learn examination method that is equivalent to VCUG for the diagnosis of vesicoureteral reflux and should be used as the diagnostic method of first choice when available given the absence of radiation exposure.

KEY POINTS

· Like VCUG, ceVUS is the diagnostic method of first choice in suspected vesicoureteral reflux and should be used preferentially given the absence of radiation exposure.. · Especially in comparison to the alternative VCUG, ceVUS is a quick-to-learn examination method.. · ceVUS can also be used to diagnose other pathologies of the lower urinary tract..

CITATION FORMAT

· Conen P, Thiemann J, Stredele R et al. Value of contrast-enhanced sonography in the diagnosis of vesicoureteral reflux. Fortschr Röntgenstr 2024; 196: 1022 - 1028.

The Intrarenal Reflux Diagnosed by Contrast-Enhanced Voiding Urosonography (ceVUS): A Reason for the Reclassification of Vesicoureteral Reflux and New Therapeutic Approach?

Vesicoureteral reflux (VUR) is defined as the urine backflow from the urinary bladder to the pyelo-caliceal system. In contrast, intrarenal reflux (IRR) is the backflow of urine from the renal calyces into the tubulointerstitial space. VURs, particularly those associated with IRR can result in reflux nephropathy when accompanied by urinary tract infection (UTI). The prevalence of IRR in patients with diagnosed VUR is 1-11% when using voiding cystourethrography (VCUG), while 11.9-61% when applying the contrast-enhanced voiding urosonography (ceVUS). The presence of IRR diagnosed by VCUG often correlates with parenchymal scars, when diagnosed by a 99mTc dimercaptosuccinic acid scan (DMSA scan), mostly in kidneys with high-grade VURs, and when diagnosed by ceVUS, it correlates with the wide spectrum of parenchymal changes on DMSA scan. The study performed by both ceVUS and DMSA scans showed IRRs associated with non-dilated VURs in 21% of all detected VURs. A significant difference regarding the existence of parenchymal damage was disclosed between the IRR-associated and IRR-non-associated VURs. A higher portion of parenchymal changes existed in the IRR-associated VURs, regardless of the VUR grade. That means that kidneys with IRR-associated VURs represent the high-risk group of VURs, which must be considered in the future classification of VURs. When using ceVUS, 62% of places where IRR was found were still unaffected by parenchymal changes. That was the basis for our recommendation of preventive use of long-term antibiotic prophylaxis until the IRR disappearance, regardless of the VUR grade. We propose a new classification of VURs using the ceVUS method, in which each VUR grade is subdivided based on the presence of an IRR.

Update and Summary of the European Association of Urology/European Society of Paediatric Urology Paediatric Guidelines on Vesicoureteral Reflux in Children

BACKGROUND AND OBJECTIVE

The prescriptive literature on vesicoureteral reflux (VUR) is still limited and thus the level of evidence is generally low. The aim of these guidelines is to provide a practical approach to the treatment of VUR that is based on risk analysis and selective indications for both diagnostic tests and interventions. We provide a 2023 update on the chapter on VUR in children from the European Association of Urology (EAU) and European Society for Paediatric Urology (ESPU) guidelines.

METHODS

A structured literature review was performed for all relevant publications published from the last update up to March 2022.

KEY FINDINGS AND LIMITATIONS

The most important updates are as follows. Bladder and bowel dysfunction (BBD) is common in toilet-trained children presenting with urinary tract infection (UTI) with or without primary VUR and increases the risk of febrile UTI and focal uptake defects on a radionuclide scan. Continuous antibiotic prophylaxis (CAP) may not be required in every VUR patient. Although the literature does not provide any reliable information on CAP duration in VUR patients, a practical approach would be to consider CAP until there is no further BBD. Recommendations for children with febrile UTI and high-grade VUR include initial medical treatment, with surgical care reserved for CAP noncompliance, breakthrough febrile UTIs despite CAP, and symptomatic VUR that persists during long-term follow-up. Comparison of laparoscopic extravesical versus transvesicoscopic ureteral reimplantation demonstrated that both are good option in terms of resolution and complication rates. Extravesical surgery is the most common approach used for robotic reimplantation, with a wide range of variations and success rates.

CONCLUSIONS AND CLINICAL IMPLICATIONS

This summary of the updated 2023 EAU/ESPU guidelines provides practical considerations for the management and diagnostic evaluation of VUR in children.

ADVANCING PRACTICE

For children with VUR, it is important to treat BBD if present. A practical approach regarding the duration of CAP is to consider administration until BBD resolution.

PATIENT SUMMARY

We provide a summary and update of guidelines on the diagnosis and management of urinary reflux (where urine flows back up through the urinary tract) in children. Treatment of bladder and bowel dysfunction is critical, as this is common in toilet-trained children presenting with urinary tract infection.