Which cystography in the diagnosis and grading of vesicoureteral reflux?

Contrast-enhanced voiding urosonography, a possible candidate for the diagnosis of vesicoureteral reflux in children and adolescents; a systematic review and meta-analysis

INTRODUCTION

The diagnostic value of contrast-enhanced voiding urosonography (ceVUS) in the diagnosis of vesicoureteral reflux (VUR) is still a subject of dispute.

OBJECTIVE

Assessing the diagnostic value of ceVUS in VUR, performing a systematic review and meta-analysis.

METHODS

An extensive search on Medline, Embase, Scopus and Web of Science databases was conducted by the end of 2020. The inclusion criteria were studies on the diagnostic value of ceVUS for VUR. Two independent researchers summarized the included articles and the findings were reported as area under the curve (AUC), sensitivity and specificity with a 95% confidence interval (95% CI).

RESULTS

Finally, the data of 36 articles were included in the present meta-analysis (2768 children). The VUS assessment showed that 1297 of the cases were true positives, 3661 were true negatives, 398 were false positives and 169 were false negatives. The AUC, sensitivity and specificity of ceVUS with the first-generation contrast agent in the diagnosis of VUR in children and adolescents were obtained as 0.97 (95% CI: 0.95, 0.98), 0.92 (95% CI: 0.86, 0.96) and 0.94 (95% CI: 0.95, 0.98), respectively. Moreover, AUC, sensitivity and specificity of ceVUS with the second-generation contrast agent were 0.97 (95% CI: 0.95, 0.98), 0.93 (95% CI: 0.86, 0.97) and 0.91 (95% CI: 0.86, 0.95).

CONCLUSION

The findings of the present study showed that diagnostic value of ceVUS with both first-generation and second-generation contrast agents for VUR, is in an excellent range. Although it seems that ceVUS may be applied as a radiation-free alternative to imaging techniques such as VCUG, the presence of 3% of false negatives in this test is a limitation. Since the lack of punctual management of VUR is associated with serious renal complications in children, future studies are recommended to be focused on the evaluation of the Benefit-risk evaluation of ceVUS.

The Change in the Renal Pelvis Anterior-Posterior Diameter Between Prevoiding and Postvoiding Status, and Its Correlation With Vesicoureteral Reflux

In this study, our aim was to evaluate the significance of the change in renal pelvis anterior-posterior diameter (RPAPD) before and after micturition between vesicoureteral reflux (VUR)-positive and -negative patients to whom had voiding cystourethrography (VCUG) was performed.In this study, 69 children, age ranging from 0 to 12 years, were included. Before the VCUG imaging, the RPAPD was measured first with a full bladder and then after urination via ultrasound (US). The differences between in RPAPD measurements were noted and values compared made among VUR-positive and -negative children. Data distribution was inhomogeneous, and the Wilcoxon Sign Rank test was utilized instead of Student t test. There was no statistically significant difference in prevoiding and postvoiding RPAPD in VUR (+) and VUR (-) patients (P = 0.672). There was no statistically significant relation between VUR and the presence of hydronephrosis (P = 0.126). Vesicoureteral reflux is more common in patients with urinary tract infections (UTI) (P = 0.001). There was no statistically significant relationship between prevoiding and postvoiding RPAPD change and VUR diagnosis (P = 0,164).Ultrasound is the modality of choice for urinary system evaluation. Diagnosis of hydronephrosis via US is not sufficient in predicting VUR; however, indirect findings may reveal the diagnosis. A decrease in RPAPD in postvoiding US evaluation may not rule out the VUR diagnosis for this reason further imaging modalities, such as VCUG, should be taken into consideration for the patients with clinical suspicion.

Brazilian consensus on vesicoureteral reflux-recommendations for clinical practice

Introduction

Vesicoureteral Reflux (VUR) is characterized by a retrograde flow of urine from the bladder into the ureters and kidneys. It is one of the most common urinary tract anomalies and the major cause of urinary tract infection (UTI) in the first years of life. If not properly diagnosed and treated can lead to recurrent UTI, renal scar and, in severe cases, to end stage renal disease. Despite recent advances in scientific and technological knowledge, evaluation and treatment of VUR is still controversial and there is still considerable heterogeneity in evaluation methods and therapeutic approaches. The aim of the present consensus is to give a practical orientation on how to evaluate and treat VUR.

Methods

The board of Pediatric Urology of the Brazilian Society of Urology joined a group of experts and reviewed all important issues on Vesicoureteral Reflux evaluation and treatment and elaborated a draft of the document. On November 2017 the panel met to review, discuss and write a consensus document.

Results and Discussion

Vesicoureteral Reflux is a common and challenging problem in children. Children presenting with Vesicoureteral Reflux require careful evaluation and treatment to avoid future urinary tract infections and kidney scars. The panel addressed recommendations on up to date choice of diagnosis evaluation and therapies.

Current Management of Urinary Tract Infection and Vesicoureteral Reflux

Urinary tract infection (UTI) is defined as the growth of a significant number of microorganisms of a single species in the urine, in the presence of symptoms. Symptoms in young children are non-specific such as fever without focus; young infants may manifest with irritability, failure to thrive, jaundice, vomiting and diarrhea. Older children usually have symptoms of cystitis or pyelonephritis. Symptoms of cystitis are dysuria, frequency, new onset incontinence and malodorous urine while symptoms of pyelonephritis are high grade fever, flank pain and vomiting. Rapid urine testing by microscopy for pus cells, dipstick testing for leukocyte esterase and nitrite, and enhanced urinalysis are supportive tests. Urine culture samples should be collected with proper technique and results interpreted for significant growth accordingly. Antibiotic therapy for 7-14 d for complicated UTI and 3-4 d for uncomplicated UTI is adequate. Further evaluation is recommended clinically for bladder-bowel dysfunction and obvious anatomical defects and by imaging for vesicoureteral reflux (VUR), usually by micturating cystourethrography (MCU). Since MCU involves exposure to radiation and urethral catheterization, it is now reserved for children with parenchymal involvement or recurrent UTI. VUR is the backward flow of urine into one or both ureters. Clinical manifestations other than UTI include incidental diagnosis on antenatal ultrasonography. Reflux nephropathy, the renal scarring associated with VUR may manifest clinically as hypertension, proteinuria and renal failure. The management of VUR is primarily with antibiotic prophylaxis. Anatomical correction is indicated in case of breakthrough febrile UTI. No intervention has been shown to reduce renal scarring.

Off-label-use of sulfur-hexafluoride in voiding urosonography for diagnosis of vesicoureteral reflux in children: A survey on adverse events

AIM

To evaluate the risk profile of sulfur hexafluoride in voiding urosonography (VUS) based on a large cohort of children.

METHODS

Since 2011 sulfur hexafluoride (SH, SonoVue^®, Bracco, Italy) is the only ultrasound contrast available in the European Union and its use in children has not been approved. Within a 4-year-period, 531 children with suspected or proven vesicoureteral reflux (f/m = 478/53; mean age 4.9 years; 1 mo-25.2 years) following parental informed consent underwent VUS with administration of 2.6 ± 1.2 mL SH in a two-center study. A standardized telephone survey on adverse events was conducted three days later.

RESULTS

No acute adverse reactions were observed. The survey revealed subacute, mostly self-limited adverse events in 4.1% (22/531). The majority of observed adverse events (17/22) was not suspected to be caused by an allergic reaction: Five were related to catheter placement, three to reactivated urinary tract infections, five were associated with perineal disinfection before voiding urosonography or perineal dermatitis and four with a common cold. In five patients (0.9%) hints to a potential allergic cause were noted: Perineal urticaria was reported in three interviews and isolated, mild fever in two. These were minor self-limited adverse events with a subacute onset and no hospital admittance was necessary. Ninety-six point two percent of the parents would prefer future VUS examinations with use of SH.

CONCLUSION

No severe adverse events were observed and indications of self-limited minor allergic reactions related to intravesical administration of SH were reported in less than 1%.

Premature Destruction of Microbubbles during Voiding Urosonography in Children and Possible Underlying Mechanisms: Post Hoc Analysis from the Prospective Study

The aim of this study is to describe premature microbubbles destruction with contrast-enhanced voiding urosonography (ce-VUS) in children using 2nd-generation ultrasound contrast agents (UCA) and to hypothesize about the reason. 141 children (61 females and 80 males) were included in the study, with mean age of 3.3 years (range 4 weeks–16.0 years), who underwent ce-VUS examination between 2011 and 2014. Premature destruction of the microbubbles in the urinary bladder during ce-VUS was observed in 11 children (7.8%). In all these cases the voiding phase of ce-VUS examination could not be performed because of destroyed UCA microbubbles. This was noted in anxious, crying infants and children with restricted voiding. The premature destruction of ultrasound contrast agent during ce-VUS is an underreported, important limitation of ce-VUS, which prevents evaluation of the voiding phase and the establishment of vesicoureteric reflux (VUR). This was particularly noted in crying infants and children.

Voiding urosonography with second-generation contrast as a main tool for examining the upper and lower urinary tract in children. Pilot Study

INTRODUCTION

In this series, we analyse the diagnostic efficacy of serial voiding urosonography (VUS) with second-generation contrast, combined harmoniously and specifically with contrast technology, in the examination of the urinary tract in children. This examination includes the diagnosis and follow-up for vesicoureteral reflux (VUR) and urethral disorders, mainly those of the posterior urethral valve (PUV).

PATIENTS AND METHODS

After obtaining informed consent, a prospective study was conducted using urosonography with second-generation contrast (sulphur hexafluoride microbubbles, SonoVue®) from November 2014 to October 2015 (1 year) in paediatric patients with suspected VUR or PUV impairment. For patients with a high suspicion of VUR and in cases of PUV, we also conducted simultaneous voiding cystourethrography (VCUG).

RESULTS

We studied 40 patients (80 renal units) between the ages of 2 months and 13 years (median age, 14 months). The indication for the test was a suspected VUR (36 patients, group A) and PUV follow-up (4 patients, group B). The test was correlated with VCUG in 16 patients (12 cases with high suspicion of VUR in group A and with 4 cases of PUV in group B). The visualisation of the urethra was appropriate in cases of dilation or urethral stricture. For 3 of these patients with bilateral VUR demonstrated in the serial VUS, the VCUG showed only unilateral VUR in 2 of the patients and no VUR in 1 of the patients (κ=.73).

DISCUSSION

We have shown that the visualisation of the urethra is no longer a limitation and that serial VUS can be superior to conventional VCUG in diagnosing VUR.

Value of sonographic anterior-posterior renal pelvis measurements before and after voiding for predicting vesicoureteral reflux in children

PURPOSE

Voiding cystourethrography (VCUG) is the gold standard for diagnosing vesicoureteral reflux (VUR), but it is important to minimize the use of VCUG because of the urinary catheterization and radiation exposure required. Ultrasound (US) observations suggest that pelvicalyceal dilatation varies according to the degree of bladder fullness in children with urinary tract infection. The aim of this study was to assess whether anterior-posterior (AP) measurements of the renal pelvis on US before and after voiding can be used as a screening tool while predicting the presence of VUR in children.

METHODS

The subjects were toilet-trained children older than 4 years who required VCUG. Two groups were established based on the VCUG results: a VUR group of 40 kidney units (each unit defined as calyces and ureter) that exhibited different severities of reflux, and a control group of 68 kidney units unaffected by VUR. Prior to VCUG, US AP measurements of the renal pelvis of each kidney unit were recorded when the urinary bladder was full and again after bladder emptying. The change in AP measurement from before to after voiding was compared between the two groups.

RESULTS

The mean change in AP measurements from before to after voiding in the VUR group was significantly greater than that in the control group (p = 0.003).

CONCLUSIONS

Comparing US AP measurements of the renal pelvis before and after voiding is useful for identifying children who are suspected to have VUR and thus require immediate VCUG.

Successful management of neonatal renal venous thrombosis

Renal vein thrombosis is the most common vascular condition involving the newborn kidney and it can result in severe renal damage. We report a newborn with renal vein thrombosis treated with continuous infusion of unfractionated heparin who had normal total renal function after 3 years of follow up, despite reduction of the functional contribution of the affected kidney.

Safety of contrast-enhanced ultrasound in children for non-cardiac applications: a review by the Society for Pediatric Radiology (SPR) and the International Contrast Ultrasound Society (ICUS)

The practice of contrast-enhanced ultrasound in children is in the setting of off-label use or research. The widespread practice of pediatric contrast-enhanced US is primarily in Europe. There is ongoing effort by the Society for Pediatric Radiology (SPR) and International Contrast Ultrasound Society (ICUS) to push for pediatric contrast-enhanced US in the United States. With this in mind, the main objective of this review is to describe the status of US contrast agent safety in non-cardiac applications in children. The five published studies using pediatric intravenous contrast-enhanced US comprise 110 children. There is no mention of adverse events in these studies. From a European survey 948 children can be added. In that survey six minor adverse events were reported in five children. The intravesical administration of US contrast agents for diagnosis of vesicoureteric reflux entails the use of a bladder catheter. Fifteen studies encompassing 2,951 children have evaluated the safety of intravesical US contrast agents in children. A European survey adds 4,131 children to this group. No adverse events could be attributed to the contrast agent. They were most likely related to the bladder catheterization. The existing data on US contrast agent safety in children are encouraging in promoting the widespread use of contrast-enhanced US.

Febrile urinary tract infections in young children: recommendations for the diagnosis, treatment and follow-up

We report the recommendations for the diagnosis, treatment, imaging evaluation and use of antibiotic prophylaxis in children with the first febrile urinary tract infection, aged 2 months to 3 years. They were prepared by a working group of the Italian Society of Pediatric Nephrology after careful review of the available literature and a consensus decision, when clear evidence was not available.

CONCLUSION

These recommendations are endorsed by the Italian Society of Pediatric Nephrology. They can also be a tool of comparison with other existing guidelines in issues in which much controversy still exists.

A comparison of echo-enhanced voiding urosonography with X-ray voiding cystourethrography in the first year of life

BACKGROUND

Second-generation echo-enhanced voiding urosonography (VUS) with improved contrast-specific ultrasound (US) techniques is increasingly being used for vesicoureteric reflux (VUR) detection.

AIM

To compare VUS with X-ray voiding cystourethrography (VCUG) and to evaluate the predictive value of pelvicalyceal dilatation for detecting VUR in the first year of life.

MATERIALS AND METHODS

Sixty-six children younger than one were investigated by US, VUS and VCUG. VCUG represented the reference method for VUR detection.

RESULTS

According to VCUG, VUR was present in 16/132 (12%) renal units. VUS confirmed all these and additionally revealed VUR in 26 renal units (all together 42/132 (32%) renal units with VUR). It should be noted that all VUR detected only with VUS and missed by VCUG were of grades II and III. In 27/92 (29%) US normal and in 15/40 (37%) renal units with pelvicalyceal dilatation, VUR was detected by VUS.

CONCLUSION

We believe that VUS could safely replace VCUG in VUR detection in infants, with no regard to the degree of abnormality of the upper urinary tract seen on US. VCUG should be limited only to cases where bladder and/or urethra pathology are suspected.

Comparative study of color Doppler voiding urosonography without contrast enhancement and direct radionuclide voiding cystography for diagnosis of vesicoureteric reflux in children

OBJECTIVES

Most available studies investigating the diagnostic accuracy of color Doppler voiding urosonography in the detection of vesicoureteric reflux used an echo contrast agent. It is unknown whether echo contrast agents are necessary for diagnosis or follow-up of vesicoureteric reflux. We compared color Doppler voiding urosonography without contrast enhancement and direct radionuclide voiding cystography in the detection and grading of vesicoureteric reflux with respect to the sex and age of patients as well as the severity of reflux.

METHODS

In the 66 patients enrolled (56 girls and 10 boys), 132 renoureteral units were investigated. All patients under went Doppler voiding urosonography and direct radionuclide voiding cystography within 3 hours. Direct radionuclide voiding cystography was used as the reference standard.

RESULTS

Our results indicate good overall sensitivity (83%) and specificity (77%) for color Doppler voiding urosonography without contrast enhancement in comparison with direct radionuclide voiding cystography. As the age of the patients decreased, the sensitivity of urosonography increased, reaching 100% among patients younger than 1 year. In the comparison of different grades of reflux severity, we found that the sensitivity and specificity were elevated as the grade increased (both parameters reaching 100% in the most severe cases). Severity grading was equal between the two methods.

CONCLUSIONS

We have shown that Doppler voiding urosonography without contrast enhancement is a comparably reliable method versus direct radionuclide voiding cystography in the detection and grading of vesicoureteric reflux, especially at higher grades of reflux and in children younger than 1 year.

Voiding urosonography with US contrast agent for the diagnosis of vesicoureteric reflux in children: an update

Voiding urosonography (VUS) entails the intravesical administration of US contrast agent (USCA) for the diagnosis of vesicoureteric reflux (VUR). VUS is now recognized as a practical, safe, radiation-free modality with comparable or higher sensitivity than direct radionuclide cystography (DRNC) and voiding cystourethrography (VCUG), respectively. An extensive review of the literature regarding both the procedural aspects and comparative diagnostic values of VUS has been published (Darge Pediatr Radiol 38:40-63, 2008a, b). The aim of this review is to provide an update on various facets of VUS that have taken place since the publication of the above-mentioned two reviews.

Controversies in the management of vesicoureteral reflux: the rationale for the RIVUR study

The current management of vesicoureteral reflux (VUR) focuses on the prevention of urinary tract infections (UTI), with curative surgery being limited to those children that fail conservative measures. This is based on the assumption that UTIs are preventable with the use of prophylatic antibiotics, leading to reduction of renal scarring, and the possibility that VUR in children can resolve spontaneously.

METHODS

Review of the recent literature has demonstrated a growing concern that antibiotic prophylaxis may not lead to prevention of UTIs. Additionally, data indicate that renal scarring may not be preventable with antibiotic prophylaxis or even surgical correction of VUR. An overview of all of the current controversies is presented in this paper.

RESULTS

Does antibiotic prophylaxis lead to reduction in UTIs in children with VUR? To address this question, the National Institutes of Health have developed a randomized placebo-controlled study of children with VUR (the RIVUR Study), identified following the development of a UTI.

CONCLUSIONS

There are far reaching consequences of the results of the RIVUR Study. If antibiotic prophylaxis does not prevent UTI in children with VUR, or lead to reduction in renal scarring, does identification of VUR provide any benefits? Perhaps appropriate treatment of UTI may be all that is necessary for preserving renal function. Final answers will have to wait until the completion of this study.

Direct radionuclide cystography imaging in colovesical fistula due to inguinal hernia operation complication

Colovesical fistula is an abnormal connection between the enteric and urinary systems, usually sigmoid colon, caused by various conditions. One cause of colovesical fistula is iatrogenic injury, such as induced by inguinal hernia surgery. We present a case of colovesical fistula. A 57-year-old male was admitted to a local hospital with complaints of dysuria and pneumaturia. He had a past history of total extraperitoneal laparoscopic inguinal hernia repair operation 7 years previously for bilateral inguinal hernia. The case was assessed with radiologic and scintigraphic techniques. Radiologic techniques (plain abdominal radiography, intravenous pyelogram, ultrasound examination, double-contrast barium enema, CT, MRI) were inadequate to determine the colovesical fistula. The colovesical fistula was visualized with direct radionuclide voiding cystography as an alternative scintigraphic method.

Diagnostic approach to reflux in 2007

There is ongoing controversy regarding the association between vesicoureteric reflux (VUR), recurrent urinary tract infections (UTI), and renal damage. Despite this, routine work up for VUR is still recommended after febrile UTI in most children. The present article reviews the indications and imaging modalities available for VUR diagnosis. Alternative newer techniques like MR cystography and voiding urosonography are discussed. The increasing evidence of the role of DMSA scans in managing children with VUR is highlighted.