Reliability of grading of vesicoureteral reflux and other findings on voiding cystourethrography

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.

Quantification of vesicoureteral reflux using machine learning

INTRODUCTION

The radiographic grading of voiding cystourethrogram (VCUG) images is often used to determine the clinical course and appropriate treatment in patients with vesicoureteral reflux (VUR). However, image-based evaluation of VUR remains highly subjective, so we developed a supervised machine learning model to automatically and objectively grade VCUG data.

STUDY DESIGN

A total of 113 VCUG images were gathered from public sources to compile the dataset for this study. For each image, VUR severity was graded by four pediatric radiologists and three pediatric urologists (low severity scored 1-3; high severity 4-5). Ground truth for each image was assigned based on the grade diagnosed by a majority of the expert assessors. Nine features were extracted from each VCUG image, then six machine learning models were trained, validated, and tested using 'leave-one-out' cross-validation. All features were compared and contrasted, with the highest-ranked then being used to train the final models.

RESULTS

F1-score is a metric that is often used to indicate performance accuracy of machine learning models. When using the highest-ranked VCUG image features, F1-scores for the support vector machine (SVM) and multi-layer perceptron (MLP) classifiers were 90.27 % and 91.14 %, respectively, indicating a high level of accuracy. When using all features combined, F1 scores were 89.37 % for SVM and 90.27 % for MLP.

DISCUSSION

These findings indicate that a distorted pattern of renal calyces is an accurate predictor of high-grade VUR. Machine learning protocols can be enhanced in future to improve objective grading of VUR.

Development and multi-institutional validation of a deep learning model for grading of vesicoureteral reflux on voiding cystourethrogram: a retrospective multicenter study

Background

Voiding cystourethrography (VCUG) is the gold standard for the diagnosis and grading of vesicoureteral reflux (VUR). However, VUR grading from voiding cystourethrograms is highly subjective with low reliability. This study aimed to develop a deep learning model to improve reliability for VUR grading on VCUG and compare its performance to that of clinicians.

Methods

In this retrospective study in China, VCUG images were collected between January 2019 and September 2022 from our institution as an internal dataset for training and 4 external data sets as external testing set for validation. Samples were divided into training (N = 1000) and validation sets (N = 500), internal testing set (N = 168), and external testing set (N = 280). An ensemble learning-based model, Deep-VCUG, using Res-Net 101 and the voting methods was developed to predict VUR grade. The grading performance was assessed using heatmaps, area under the receiver operating characteristic curve (AUC), sensitivity, specificity, accuracy, and F1 score in the internal and external testing set. The performances of four clinicians (2 pediatric urologists and 2 radiologists) with and without the Deep-VCUG assisted to predict VUR grade were explored in external testing sets.

Findings

A total of 1948 VCUG images were collected (Internal dataset = 1668; multi-center external dataset = 280). For assessing unilateral VUR grading, the Deep-VCUG achieved AUCs of 0.962 (95% confidence interval [CI]: 0.943-0.978) and 0.944 (95% [CI]: 0.921-0.964) in the internal and external testing sets, respectively, for bilateral VUR grading, the Deep-VCUG also achieved high AUCs of 0.960 (95% [CI]: 0.922-0.983) and 0.924 (95% [CI]: 0.887-0.957). The Deep-VCUG model using voting method outperformed single model and clinician in terms of classification based on VCUG image. Moreover, Under the Dee-VCUG assisted, the classification ability of junior and senior clinicians was significantly improved.

Interpretation

The Deep-VCUG model is a generalizable, objective, and accurate tool for vesicoureteral reflux grading based on VCUG imaging and had good assistance with clinicians to VUR grading applicability.

Funding

This study was supported by Natural Science Foundation of China, "Fuqing Scholar" Student Scientific Research Program of Shanghai Medical College, Fudan University, and the Program of Greater Bay Area Institute of Precision Medicine (Guangzhou).

A quantitative analysis of voiding cystourethrogram features confirms the association between high-grade vesicoureteral reflux with male sex, younger age, and hydronephrosis

INTRODUCTION

Vesicoureteral reflux (VUR) is commonly diagnosed in the workup of urinary tract infections or hydronephrosis in children. Traditionally, VUR severity is graded subjectively based on voiding cystourethrogram (VCUG) imaging. Herein, we characterized the association between age, sex, and indication for VCUG, by employing standardized quantitative features.

METHODS

We included renal units with a high certainty in VUR grade (>80% consensus) from the qVUR model validation study at our institution between 2013 and 2019. We abstracted the following variables: age, sex, laterality, indication for VCUG, and qVUR parameters (tortuosity, ureter widths on VCUG). High-grade VUR was defined as grade 4 or 5 The association between each variable and VUR grade was assessed.

RESULTS

A total of 443 patients (523 renal units) were included, consisting of a 48:52 male/female ratio. The median age at VCUG was 13 months. Younger age at VCUG (<6 months) was associated with greater odds of severe VUR (odds ratio [OR] 2.0), and there was a weak correlation between age and VUR grade (ρ=-0.17). Male sex was associated with increased odds of high-grade VUR (OR 2.7). VCUGs indicated for hydronephrosis were associated with high-grade VUR (OR 4.1) compared to those indicated for UTI only. Ureter tortuosity and width were significantly associated with each clinical variable and VUR severity.

CONCLUSIONS

Male sex, younger age (<6 months), and history of hydronephrosis are associated with both high-grade VUR and standardized quantitative measures, including greater ureter tortuosity and increased ureteral width. This lends support to quantitative assessment to improve reliability in VUR grading.

Spontaneous vesicoureteral reflux resolution curves based on ureteral diameter ratio

INTRODUCTION

Various factors influence the clinical course of vesicoureteral reflux (VUR) in the pediatric population. Distal ureteral diameter ratio (UDR) is an objective measure reflective of ureterovesical junction anatomy that has been shown to independently predict both spontaneous resolution and breakthrough febrile urinary tract infection (UTI) in children with primary reflux. UDR resolution curves were created, hypothesizing that a UDR value existed at which spontaneous resolution was unlikely to occur.

MATERIALS AND METHODS

UDR was computed by measuring largest ureteral diameter within the pelvis and dividing by the distance between L1-L3 vertebral bodies. Recursive partitioning with 10-fold cross validation methodology for time to event data, utilizing martingale residuals was used to create high and low risk groups based on UDR, and stratified by age at diagnosis and laterality.

RESULTS

Three hundred and four patients (226 female, 78 male) were analyzed with a mean age at diagnosis of 1.55 ± 1.98 years. Unilateral reflux (p = 0.02), VUR grades 1-3 (p < 0.001), and lower UDR (p < 0.001) were associated with spontaneous resolution on univariate analysis. UDR values were categorized into risk groups based on recursive partitioning. Low risk patients (those with UDR <0.30) achieved VUR resolution faster and with a continuing rate compared to the high-risk group (≥0.30), which had persistent reflux after 3 years [Summary Figure]. When the 0.30 cutoff was applied randomly to patients in test group, the cutoff significantly discriminated between low and high-risk patients (log rank test p = 0.02).

DISCUSSION

Primary VUR is often a self-limiting diagnosis, with conservative management favored in low-risk children, UDR may be used to help distinguish those children who may benefit from intervention. Unlike traditional VUR grading where children with any grade of reflux may spontaneously resolve, there appears to be a consistent UDR cutoff whereby patients are very unlikely to spontaneously resolve, regardless of length of follow-up. Therefore, parents of children with a UDR above the 0.3 cutoff, regardless of VUR grade, may be counselled that VUR is very unlikely to resolve over time - thereby reducing the number of VCUGs and length of time these patients are on prophylactic antibiotic prior to surgical intervention.

CONCLUSIONS

Children with primary VUR and a UDR of greater than 0.30 are significantly less likely to spontaneously resolve regardless of length of follow-up, and resolution after 3 years was rare. UDR provides objective prognostic information facilitating individualized patient management.

Accuracy of contrast-enhanced voiding urosonography using Optison™ for diagnosis of vesicoureteral reflux in children

BACKGROUND

There is limited quality of evidence regarding the accuracy of contrast-enhanced voiding urosonography (ceVUS) for diagnosis of vesicoureteral reflux (VUR) compared to fluoroscopic voiding cystourethrography (VCUG), and minimal data on the use of the ultrasound contrast agent Optison™ for this purpose.

OBJECTIVE

To compare the accuracy of ceVUS using Optison™ to VCUG, and to assess inter-rater agreement regarding presence and grading of VUR.

STUDY DESIGN

In this retrospective investigation, all sequential ceVUS with Optison™ and VCUG studies performed in children between 2014 and 2017 were reviewed. Two raters independently graded all ceVUS studies using a 5-point scale. CeVUS sensitivity and specificity were estimated separately for each rater using the VCUG report as the ground truth for presence and degree of VUR. Logistic and ordinary linear regression models assessed rater-report agreement and inter-rater agreement for each kidney, Optison™ dose, and referral diagnosis.

RESULTS

97 children (51 females) with 101 paired studies were included. Sensitivity and specificity of ceVUS for VUR detection were identical for both raters: right kidney 75%/90.9%; left kidney 85.7%/78.9% (Figure). There was no statistically significant difference in disagreement between raters and the VCUG report for the right or left kidney. Inter-rater agreement on ceVUS grading was 90% and 88% for right and left kidneys, respectively. There was a significant negative association between fetal hydronephrosis vs urinary tract infection and disagreement between Rater 2 and the VCUG report for the left kidney. There were no other significant associations with respect to either kidney, Optison™ dose, or referral diagnosis.

DISCUSSION

Our study showed that detection of VUR with ceVUS and Optison™ is comparable to fluoroscopic VCUG. Based on the VCUG reports, the incidence of VUR in our patient population was substantially lower than in the meta-analysis of Chua et al. and in the study of Kim et al. The explanation for the large discrepancy in VUR incidence may reflect differences in the patient populations, and in our reporting of VUR with respect to kidney number rather than to pelviureteral units. Study limitations include its retrospective nature and potential bias in terms of patient selection. Since VUR is an intermittent phenomenon, sequential rather than simultaneous performance of the ceVUS and fluoroscopic studies might have influenced VUR detection.

CONCLUSION

A blinded comparison of ceVUS performed with Optison™ to fluoroscopic VCUG showed moderate-good sensitivity and specificity for diagnosis of VUR.

Primary Vesicoureteral Reflux and Renal Scarring

Vesicoureteral reflux (VUR) is the commonest congenital anomaly of urinary tract in children. It is mostly diagnosed after a urinary tract infection or during evaluation for congenital anomalies of the kidney and urinary tract. High-grade VUR, recurrent pyelonephritis, and delayed initiation of antibiotic treatment are important risk factors for renal scarring. The management of VUR depends on multiple factors and may include surveillance only or antimicrobial prophylaxis; very few patients with VUR need surgical correction. Patients with renal scarring should be monitored for hypertension and those with significant scarring should also be monitored for proteinuria and chronic kidney disease.

Intravesical Botulinum toxin-A injection in pediatric overactive neurogenic bladder with Detrusor overactivity: Radiologic and clinical outcomes

Objective:

The neurogenic bladder is one of the most serious and painful disorders seen in pediatric urology clinics. The upper urinary tract can be impaired by increased bladder pressure. Botulinum toxin-A (BTX-A) is one of the new therapeutic interventions for this disease. Thus, this research was designed to determine the clinical as well as radiological outcomes intravesical BTX-A injections in patients with overactive neurogenic bladder with Detrusor over activity.

Patients and methods:

From March 2012 to March 2019, this cohort study was conducted at Shahid Labbafinejad hospital in Tehran, Iran. Thirty-five pediatric patients with a neurogenic bladder and Detrusor overactivity who fulfilled the eligibility criteria received BTX-A injections. Demographic data, including spinal cord lesions or congenital malformations, upper and lower urinary tract nuclear scans, evidence of vesicoureteral reflux (VUR) and its severity, and hydronephrosis and 72 h voiding diary before and after intervention were all recorded.

Results:

The mean ± standard deviation age of participants was 9.47 ± 4.61 years. After injection, nocturia and urination frequency as general symptoms of the overactive neurogenic bladder improved ( p < 0.05). Also, the severity of hydronephrosis was decreased in 33% of patients following injection. In our study, 32 out of 35 patients had vesicoureteral reflux. Of those, there was complete resolution and downgrading of VUR in 17 (53.12%) and 13 (40.62%) respectively. Seventeen patients (53.12%) had complete recovery post-injection from VUR.

Conclusion:

In the evaluation of voiding cystourethrography (VCUG) before and after the injection, downgrading of VUR was seen in 53% of the cases. In the 99mTc-DMSA nuclear scan before and after the injection, the appearance of a new parenchymal scar and uptake reduction was not observed, which indicates the cessation of scar formation in all patients. Although Enuresis, Urgency, Frequency, Nocturia, and UUI significantly improved after injection.

Correlation of Renal Scarring to Urinary Tract Infections and Vesicoureteral Reflux in Children

Objective

To study the association of the grade of vesicoureteral reflux (VUR) and urinary tract infections (UTI) with renal scarring at the first clinical presentation of patients who underwent antireflux surgery. Materials and methods. Between 2015 and 2020, 150 patients (194 units) who underwent antireflux surgery had dimercaptosuccinic acid (DMSA) renal scans preoperatively. Patients were classified into the nonscar and scar groups according to DMSA scan results. Moreover, cases were classified into afebrile UTI, febrile UTI, and antenatal hydronephrosis (ANH) according to the mode of presentation. We correlated the mode of presentation and the grade of VUR to the presence/absence of renal scars in both groups.

Results

The mean follow-up was 45 months preoperatively. The mode of presentation was afebrile, febrile UTIs, and antenatal hydronephrosis in (50, 14), (20, 46), and (10, 10) patients in the nonscar and scar groups, respectively. Of the 20 patients who presented ANH, 10 (50%) had scars. Clinical presentation was correlated to the presence of renal scarring and its degree. The scar group had significantly higher grades of VUR than the nonscar group (grades I–II (50 units versus 10 units), grade III (28 units versus 40 units), and grade IV–V (22 units versus 44 units) for the nonscar versus scar groups, respectively (pvalue <0.001).

Conclusion

Renal scarring is associated with higher grades of reflux and urinary tract infections. We advocate further research investigating infants who had UTIs with or without fever for early detection of reflux.

A machine learning-based approach for quantitative grading of vesicoureteral reflux from voiding cystourethrograms: Methods and proof of concept

INTRODUCTION

The objectivity of vesicoureteral reflux (VUR) grading has come into question for low inter-rater reliability. Using quantitative image features to aid in VUR grading may make it more consistent.

OBJECTIVE

To develop a novel quantitative approach to the assignment of VUR from voiding cystourethrograms (VCUG) alone.

STUDY DESIGN

An online dataset of VCUGs was abstracted and individual renal units were graded as low-grade (I-III) or high-grade (IV-V). We developed an image analysis and machine learning workflow to automatically calculate and normalize the ureteropelvic junction (UPJ) width, ureterovesical junction (UVJ) width, maximum ureter width, and tortuosity of the ureter based on three simple user annotations. A random forest classifier was trained to distinguish between low-vs high-grade VUR. An external validation cohort was generated from the institutional imaging repository. Discriminative capability was quantified using receiver-operating-characteristic and precision-recall curve analysis. We used Shapley Additive exPlanations to interpret the model's predictions.

RESULTS

41 renal units were abstracted from an online dataset, and 44 renal units were collected from the institutional imaging repository. Significant differences observed in UVJ width, UPJ width, maximum ureter width, and tortuosity between low- and high-grade VUR. A random-forest classifier performed favourably with an accuracy of 0.83, AUROC of 0.90 and AUPRC of 0.89 on leave-one-out cross-validation, and accuracy of 0.84, AUROC of 0.88 and AUPRC of 0.89 on external validation. Tortuosity had the highest feature importance, followed by maximum ureter width, UVJ width, and UPJ width. We deployed this tool as a web-application, qVUR (quantitative VUR), where users are able to upload any VCUG for automated grading using the model generated here (https://akhondker.shinyapps.io/qVUR/).

DISCUSSION

This study provides the first step towards creating an automated and more objective standard for determining the significance of VUR features. Our findings suggest that tortuosity and ureter dilatation are predictors of high-grade VUR. Moreover, this proof-of-concept model was deployed in a simple-to-use web application.

CONCLUSION

Grading of VUR using quantitative metrics is possible, even in non-standardized datasets of VCUG. Machine learning methods can be applied to objectively grade VUR in the future.

The RiVUR Study Outcomes and Implications on the Management of Vesicoureteral Reflux

The Randomized intervention for Vesicoureteral Reflux (RiVUR) study was an effort by the National Institute of Health to identify the most significant question on the management of vesicoureteral reflux (VUR), i.e. Did antibiotic prophylaxis reduce the incidence of recurrent urinary tract infections (UTI) in children with VUR? During the initial phases of the RiVUR study, several similar studies were performed that seemed to indicate a lack of benefit of antibiotic prophylaxis in VUR. However, few of these studies had the rigorous methodology and true randomization of the pediatric cohort that was studied in RiVUR. Additionally, many of these studies included children of wide age ranges and inconsistent assessments were used for identification of UTI and VUR. In 2011, the American Academy of Pediatrics (AAP) published a guideline statement for the evaluation of initial UTI in febrile children aged 2 to 24 months, which recommended against performing a Voiding Cystourethrogram (VCUG) in all children with a confirmed UTI. The goal of the AAP guidelines was to reduce the number of VCUGs being performed and potentially to reduce the number of children diagnosed with low grade VUR that seems to have low potential to cause renal injury. The RiVUR study included over 600 children identified with VUR after a 1^st or 2^nd febrile UTI randomized to prophylaxis with trimethoprim/sulfamethoxazole (TMP/SMZ), or placebo and followed over a study timeline for 2 years. Overall, a 50% reduction was noted in the incidence of recurrent febrile UTI with the utilization of prophylaxis as compared to placebo. Additional sub-group analyses have been performed on the cohorts of the study; these are also evaluated in this review to determine the overall impact of the RiVUR study on the current management of VUR.

Characteristics and Outcomes of Patients Receiving Sedation for Voiding Cystourethrography

Background

Voiding cystourethrography (VCUG) is used to diagnose vesicoureteral reflux (VUR); however, it is an invasive procedure and can be psychologically distressing. Procedural sedation is occasionally utilized to alleviate anxiety during VCUG, and some patient populations may get referred more readily for sedation than others. Sedative medications may also impact the results of the test due to their effects on smooth muscle. The goals of this study were to compare patient characteristics between those that were referred for procedural sedation and those that were not and to compare VCUG results between sedated and non-sedated patients.

Methodology

We performed a retrospective cohort study of patients aged 2-18 years undergoing VCUG during a five-year period. Sedated patients were matched with non-sedated patients controlling for referring provider and procedure year. Exclusion criteria included chronic catheterization, same-day surgery, current intensive care admission, and sedation restrictions. A total of 284 patients were included. Demographic information, medical comorbidities, and VCUG results were analyzed.

Results

There were no significant differences between sedated and non-sedated patients in any demographic variables. Neurologic, developmental, and gastrointestinal comorbidities were more common in sedated patients. On multivariate analysis, having more than one comorbid condition was the only significant predictor of referral for procedural sedation. There were no significant differences in VCUG results between sedated and non-sedated patients.

Conclusions

Patients with comorbidities were more likely to receive procedural sedation for VCUG. Procedural sedation did not have a significant impact on test results, suggesting its potential utility in relieving pain and anxiety associated with VCUG.

Diagnosis and grading of vesicoureteral reflux on voiding cystourethrography images in children using a deep hybrid model

BACKGROUND AND OBJECTIVE

Vesicoureteral reflux is the leakage of urine from the bladder into the ureter. As a result, urinary tract infections and kidney scarring can occur in children. Voiding cystourethrography is the primary radiological imaging method used to diagnose vesicoureteral reflux in children with a history of recurrent urinary tract infection. Besides the diagnosis of reflux, it is graded with voiding cystourethrography. In this study, we aimed to diagnose and grade vesicoureteral reflux in Voiding cystourethrography images using hybrid CNN in deep learning methods.

METHODS

Images of pediatric patients diagnosed with VUR between 2016 and 2021 in our hospital (Firat University Hospital) were graded according to the international vesicoureteral reflux radiographic grading system. VCUG images of 236 normal and 992 with vesicoureteral reflux pediatric patients were available. A total of 6 classes were created as normal and graded 1-5 patients.

RESULTS

In this study, a hybrid-based mRMR (Minimum Redundancy Maximum Relevance) using CNN (Convolutional Neural Networks) model is developed for the diagnosis and grading of vesicoureteral reflux on voiding cystourethrography images. Googlenet, MobilenetV2, and Densenet201 models are used as a part of the hybrid architecture. The obtained features from these architectures are examined in concatenating process. Then, these features are classified in machine learning classifiers after optimizing with the mRMR method. Among the models used in the study, the highest accuracy value was obtained in the proposed model with an accuracy rate of 96.9%.

CONCLUSIONS

It shows that the hybrid model developed according to the findings of our study can be used in the diagnosis and grading of vesicoureteral reflux in voiding cystourethrography images.

Contemporary Management of Urinary Tract Infection in Children

Urinary tract infection (UTI) is common in children, and girls are at a significantly higher risk, as compared to boys, except in early infancy. Most cases are caused by Escherichia coli Collection of an uncontaminated urine specimen is essential for accurate diagnosis. Oral antibiotic therapy for 7 to 10 days is adequate for uncomplicated cases that respond well to the treatment. A renal ultrasound examination is advised in all young children with first febrile UTI and in older children with recurrent UTI. Most children with first febrile UTI do not need a voiding cystourethrogram; it may be considered after the first UTI in children with abnormal renal and bladder ultrasound examination or a UTI caused by atypical pathogen, complex clinical course, or known renal scarring. Long-term antibiotic prophylaxis is used selectively in high-risk patients. Few patients diagnosed with vesicoureteral reflux after a UTI need surgical correction. The most consequential long-term complication of acute pyelonephritis is renal scarring, which may increase the risk of hypertension or chronic kidney disease later in life. Treatment of acute pyelonephritis with an appropriate antibiotic within 48 hours of fever onset and prevention of recurrent UTI lowers the risk of renal scarring. Pathogens causing UTI are increasingly becoming resistant to commonly used antibiotics, and their indiscriminate use in doubtful cases of UTI must be discouraged.

Management of Vesicoureteral Reflux: What Have We Learned Over the Last 20 Years?

Vesicoureteral reflux (VUR) is associated with increased risks of urinary tract infection, renal scarring and reflux nephropathy. We review advancements over the last two decades in our understanding and management of VUR. Over time, the condition may resolve spontaneously but it can persist for many years and bladder/bowel dysfunction is often involved. Some factors that increase the likelihood of persistence (e.g., high grade) also increase the risk of renal scarring. Voiding cystourethrography (VCUG) is generally considered the definitive method for diagnosing VUR, and helpful in determining the need for treatment. However, this procedure causes distress and radiation exposure. Therefore, strategies to reduce clinicians' reliance upon VCUG (e.g., after a VUR treatment procedure) have been developed. There are several options for managing patients with VUR. Observation is suitable only for patients at low risk of renal injury. Antibiotic prophylaxis can reduce the incidence of UTIs, but drawbacks such as antibiotic resistance and incomplete adherence mean that this option is not viable for long-term use. Long-term studies of endoscopic injection have helped us understand factors influencing use and the effectiveness of this procedure. Ureteral reimplantation is still performed commonly, and robot-assisted laparoscopic methods are gaining popularity. Over the last 20 years, there has been a shift toward more conservative management of VUR with an individualized, risk-based approach. For continued treatment improvement, better identification of children at risk of renal scarring, robust evidence regarding the available interventions, and an improved VUR grading system are needed.

Voiding cystourethrography and 99MTC-MAG3 renal scintigraphy in pediatric vesicoureteral reflux: what is the role of indirect cystography?

BACKGROUND

Primary vesicoureteral reflux (VUR) is the most common urological anomaly in children. Voiding cystourethrography (VCUG) is considered the reference standard for the diagnosis of VUR. Even if it is a secure and standardized technique, it is still an invasive method, hence, the effort to find an alternative method to diagnose VUR. The aim of the study is to evaluate the diagnostic accuracy of ^99mTC-MAG3 scintigraphy with indirect cystography in detecting VUR and to estimate any interobserver variability in ^99mTC-MAG3 scintigraphy interpretation.

METHODS

The authors retrospectively reviewed all the pediatric patients who underwent both a VCUG and a ^99mTC-MAG3 renal scintigraphy at the study institution between 2012 and 2016.

RESULTS

A total of 86 children (and 168 renal units) were included. MAG3 scan revealed a sensitivity of 54% and a specificity of 90% with positive predictive value of 79% and negative predictive value of 73%. Each MAG3 scintigraphy was then independently and blindly evaluated by a pediatric urologist and two nuclear physicians. After revision, the concordance between VCUG and MAG3 in reflux cases dropped from 54% to 27% (on average), and the reviewers reclassified most examinations as non-conclusive.

CONCLUSIONS

^99mTC-MAG3 renal scintigraphy with indirect cystography showed low sensitivity in detecting VUR of any grade and cannot, therefore, be proposed as completely alternative to VCUG in the diagnosis of VUR. Moreover, MAG3 scintigraphy interpretation for the diagnosis of VUR has a very high interobserver variability, mostly because of the lack of a correct and complete voiding phase.

Effect of Reader and Patient Parameters on the Performance of Last-Image-Hold for Fluoroscopic Grading of Vesicoureteric Reflux

OBJECTIVE. The purpose of this study is to determine the effect of different reader and patient parameters on the degree of agreement and the rate of misclassification of vesicoureteric reflux grading on last-image-hold frames in relation to spot-exposed frames from voiding cystourethrography (VCUG) as well as to determine the nature of reflux misclassification on last-image-hold frames. MATERIALS AND METHODS. Blinded readers conducted a retrospective evaluation of last-image-hold and spot-exposed frames of the renal fossae from 191 sequential VCUG examinations performed during a five-year period. Kappa tests were used to determine the agreement between reflux gradings and to assess the impact of reader and patient parameters. Pearson product-moment correlations were used to evaluate the effect of patient parameters on reader level of certainty regarding reflux grading. RESULTS. We measured almost perfect overall agreement for more experienced readers and substantial overall agreement for less experienced readers. Point estimates of overall misclassification were less than 2% for more experienced readers and less than 4% for less experienced readers. The readers' level of certainty about reflux grading had a positive impact on agreement values and misclassification rates. Experienced readers' most common misclassification was assigning reflux a grade of 3 on a spot-exposed frame and a grade of 2 on an equivalent last-image-hold frame. Inexperienced readers' most common misclassification involved missing reflux altogether. CONCLUSION. Instances of grade 2 reflux on last-image-hold frames may warrant supplemental evaluation with spot-exposed frames. Otherwise, a reader's level of certainty regarding reflux grading on a last-image-hold frame may help determine whether a supplemental spot-exposed frame would be beneficial.

Long-term antibiotics for preventing recurrent urinary tract infection in children

BACKGROUND

Urinary tract infection (UTI) is common in children. Symptoms include fever, lethargy, anorexia, and vomiting. UTI is caused by Escherichia coli in over 80% of cases and treatment is a course of antibiotics. Due to acute illness caused by UTI and the risk of pyelonephritis-induced permanent kidney damage, many children are given long-term (several months to 2 years) antibiotics aimed at preventing recurrence. This is the third update of a review first published in 2001 and updated in 2006, and 2011.

OBJECTIVES

To assess whether long-term antibiotic prophylaxis was more effective than placebo/no treatment in preventing recurrence of UTI in children, and if so which antibiotic in clinical use was the most effective. We also assessed the harms of long-term antibiotic treatment.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 30 July 2018 through contact with the Cochrane Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised comparisons of antibiotics with other antibiotics, placebo or no treatment to prevent recurrent UTI in children.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed and extracted information for the initial and previous updates. A random-effects model was used to estimate risk ratio (RR) and risk difference (RD) for recurrent UTI with 95% confidence intervals (CI).

MAIN RESULTS

In this update sixteen studies (2036 children randomised, 1977 analysed) were included. Seven studies (612 children) compared two or more types of antibiotics, six (1088 children) compared antibiotics with placebo or no treatment, one four-armed study compared circumcision with and without antibiotic treatment, one study compared dose of antibiotic, and one three-armed study compared two different antibiotics as well as no treatment. Of the sixteen included studies only one study was judged to be at low risk of bias for all domains, with the majority judged to be at unclear risk of bias due to very poorly reported methodology. The number of studies judged to be a low risk of bias was: selection bias (7); performance bias (4); detection bias (1); attrition bias (6); reporting bias (7); and other bias (2). The number of studies judged to be at high risk of bias was: selection bias (0); performance bias (5); detection bias (1); attrition bias (4); reporting bias (6); and other bias (1).Compared to placebo/no treatment, antibiotics lead to a modest decrease in the number of repeat symptomatic UTI in children; however the estimate from combining all studies was not certain and the confidence interval indicates low precision indicating that antibiotics may make little or no difference to risk of repeat infection (RR 0.75, 95% CI 0.28 to 1.98). When we combined only the data from studies with concealed treatment allocation, there was a similar reduction in risk of repeat symptomatic UTI in children taking antibiotics (RR 0.68) and we have greater certainty in this estimate because of the more robust study designs, the confidence interval is smaller and it does not include the point of no effect (95% CI 0.48 to 0.95). The estimated reduction in risk of repeat symptomatic UTI for children taking antibiotics was similar in children with vesicoureteric reflux (VUR) (RR 0.65, 95% CI 0.39 to 1.07) compared to those without VUR (RR 0.56, 95% CI 0.15 to 2.12) however there was considerable uncertainty due to imprecision from fewer events in the smaller group of children with VUR. There was no consistency in occurrence of adverse events, with one study having more events in the placebo group and a second study having more events in the antibiotics group. Three studies reported data for antibiotic resistance with the analysis estimating the risk of a UTI caused by a bacteria resistant to the prophylactic antibiotic being almost 2.5 times greater in children on antibiotics than for children on placebo or no treatment (RR 2.40, 95% CI 0.62 to 9.26). However the confidence interval is wide, showing imprecision and there may be little or no difference between the two groups.Eight studies involving 659 children compared one antibiotic with another but few studies compared the same combination for the same outcome so little data could be pooled. Two studies reported microbial resistance data and analysis showed that treatment with nitrofurantoin may lead to a lower risk of a UTI caused by a bacteria resistant to the treatment drug compared to children given trimethoprim-sulphamethoxazole as their prophylactic treatment (RR 0.54, 95% CI 0.31 to 0.92).

AUTHORS' CONCLUSIONS

Long-term antibiotics may reduce the risk of repeat symptomatic UTI in children who have had one or more previous UTIs but the benefit may be small and must be considered together with the increased risk of microbial resistance.

Interventions for primary vesicoureteric reflux

BACKGROUND

Vesicoureteric reflux (VUR) results in urine passing retrograde up the ureter. Urinary tract infections (UTI) associated with VUR have been considered a cause of permanent renal parenchymal damage in children with VUR. Management has been directed at preventing UTI by antibiotic prophylaxis and/or surgical correction of VUR. This is an update of a review first published in 2004 and updated in 2007 and 2011.

OBJECTIVES

The aim of this review was to evaluate the available evidence for both benefits and harms of the currently available treatment options for primary VUR: operative, non-operative or no intervention.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register to 3 May 2018 through contact with the Information Specialist using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE, and EMBASE; handsearching conference proceedings, and searching the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

RCTs in any language comparing any treatment of VUR and any combination of therapies.

DATA COLLECTION AND ANALYSIS

Two authors independently determined study eligibility, assessed quality and extracted data. Dichotomous outcomes were expressed as risk ratios (RR) with 95% confidence intervals (CI) and continuous data as mean differences (MD) with 95% CI. Data were pooled using the random effects model.

MAIN RESULTS

Thirty four studies involving 4001 children were included. Interventions included; long-term low-dose antibiotics, surgical reimplantation of ureters, endoscopic injection treatment, probiotics, cranberry products, circumcision, and oxybutynin. Interventions were used alone and in combinations. The quality of conduct and reporting of these studies was variable, with many studies omitting crucial methodological information used to assess the risk of bias. Only four of the 34 studies were considered at low risk of bias across all fields of study quality. The majority of studies had many areas of uncertainty in the risk of bias fields, reflecting missing detail rather than stated poor design.Low-dose antibiotic prophylaxis compared to no treatment/placebo may make little or no difference to the risk of repeat symptomatic UTI (9 studies, 1667 children: RR 0.77, 95% CI 0.54 to 1.09; low certainty evidence) and febrile UTI (RR 0.83, 95% CI 0.56 to 1.21; low certainty evidence) at one to two years. At one to three years, antibiotic prophylaxis made little or no difference to the risk of new or progressive renal damage on DMSA scan (8 studies, 1503 children: RR 0.73, 95% CI 0.33 to 1.61; low certainty evidence). Adverse events were reported in four studies with little or no difference between treatment groups (1056 children: RR 0.94, 95% CI 0.81 to 1.08; ), but antibiotics increased the likelihood of bacterial drug resistance threefold (187 UTIs: RR 2.97, 95% CI 1.54 to 5.74; moderate certainty evidence).Seven studies compared long-term antibiotic prophylaxis alone with surgical reimplantation of ureters plus antibiotics, but only two reported the outcome febrile UTI (429 children). Surgery plus antibiotic treatment may reduce the risk of repeat febrile UTI by 57% (RR 0.43, 95% CI 0.27 to 0.70; moderate certainty evidence). There was little or no difference in the risk of new kidney defects detected using intravenous pyelogram at 4 to 5 years (4 studies, 572 children, RR 1.09, 95% CI 0.79 to 1.49; moderate certainty evidence)Four studies compared endoscopic injection with antibiotics alone and three reported the outcome febrile UTI. This analysis showed little or no difference in the risk of febrile UTI with endoscopic injection compared to antibiotics (RR 0.74, 95% CI 0.31 to 1.78; low certainty evidence). Four studies involving 425 children compared two different materials for endoscopic injection under the ureters (polydimethylsiloxane (Macroplastique) versus dextranomer/hyaluronic acid polymer (Deflux), glutaraldehyde cross-linked (GAX) collagen (GAX) 35 versus GAX 65 and Deflux versus polyacrylate polyalcohol copolymer (VANTRIS)) but only one study (255 children, low certainty evidence) had the outcome of febrile UTI and it reported no difference between the materials. All four studies reported rates of resolution of VUR, and the two studies comparing Macroplastique with Deflux showed that Macroplastique was probably superior to dextranomer/hyaluronic acid polymer (3 months: RR 0.50, 95% CI 0.33 to 0.78; 12 months: RR 0.54 95% CI 0.35 to 0.83; low certainty evidence)Two studies compared probiotic treatment with antibiotics and showed little or no difference in risk of repeat symptomatic UTI (RR 0.82 95% CI 0.56 to 1.21; low certainty evidence)Single studies compared circumcision with antibiotics, cranberry products with no treatment, oxybutynin with placebo, two different surgical techniques and endoscopic injection with no treatment.

AUTHORS' CONCLUSIONS

Compared with no treatment, the use of long-term, low-dose antibiotics may make little or no difference to the number of repeat symptomatic and febrile UTIs in children with VUR (low certainty evidence). Considerable variation in the study designs and subsequent findings prevented drawing firm conclusions on efficacy of antibiotic treatment.The added benefit of surgical or endoscopic correction of VUR over antibiotic treatment alone remains unclear since few studies comparing the same treatment and with relevant clinical outcomes were available for analysis.

New trends in voiding cystourethrography and vesicoureteral reflux: Who, when and how?

Vesicoureteral reflux, retrograde flow of urine from the bladder into the upper urinary tract, is one of the most common urological diagnoses in the pediatric population. Diagnosis and subsequent management of urinary reflux have become increasingly debated in the past decade, with divergent opinions over which patients should be evaluated for reflux, and when detected, which children should receive intervention. Although some argue that vesicoureteral reflux is a "phenotype" that often resolves without intervention, others contest that untreated reflux has the potential to cause irreversible renal damage over time. Voiding cystourethrogram images the urethra and bladder during both bladder filling and emptying, as well as the ureters and kidneys when reflux is present, and is considered the gold standard for diagnosing vesicoureteral reflux. Once detected, therapeutic options for urinary reflux are diverse, ranging from observation with or without low-dose antibiotic prophylaxis to a variety of operative interventions. Management should be based on a multitude of factors including patient age, risk of subsequent urinary tract infections, risk of renal parenchymal injury, a given child's projected clinical course and parental preference. Over the past two decades, investigators have elucidated many crucial voiding cystourethrogram findings in addition to grade that provide significant prognostic information and are useful in determining the best course of action for a child on a more individualized basis.

Managing vesicoureteral reflux in children: making sense of all the data

Current management of vesicoureteral reflux (VUR) in children is the result of a steady albeit controversial evolution of data and thinking related to the clinical impact of VUR and urinary tract infection (UTI) in children, the value of clinical screening, and the relative impact of testing and interventions for VUR. While controversy continues, there is consensus on the importance of bladder dysfunction on VUR outcomes, the likelihood of VUR resolution, and the fact that not all children with VUR require active treatment. Early efforts to define risk stratification hold the most promise to provide more patient-specific treatment of UTI and VUR in children.

Pediatric voiding cystourethrography: An essential examination for urologists but a terrible experience for children

Voiding cystourethrography is the most important fluoroscopic examination in pediatric urology for the investigation of lower urogenital tract diseases, such as vesicoureteral reflux or urethral stricture. However, this invasive procedure imposes a significant burden on children and their parents, and recently there has been a paradigm shift in the diagnosis and treatment of vesicoureteral reflux. In the 2011 revision, the American Academy of Pediatrics guidelines on urinary tract infection recommended abandoning routine voiding cystourethrography after the first febrile urinary tract infection. In 2014, the randomized intervention for children with vesicoureteral reflux study recommended discontinuation of routine continuous antibiotic prophylaxis for vesicoureteral reflux. The time is now ripe to radically reconsider indications for voiding cystourethrography and the procedure itself.

Distal Ureteral Diameter Ratio is Predictive of Breakthrough Febrile Urinary Tract Infection

PURPOSE

Distal ureteral diameter ratio is an objective measure that is prognostic of spontaneous resolution of vesicoureteral reflux. Along with likelihood of resolution, improved identification of children at risk for recurrent febrile urinary tract infections may impact management decisions. We evaluated the usefulness of ureteral diameter ratio as a predictive factor for breakthrough febrile urinary tract infections.

MATERIALS AND METHODS

Children with primary vesicoureteral reflux and detailed voiding cystourethrogram were identified. Ureteral diameter ratio was computed by measuring largest ureteral diameter within the pelvis and dividing by the distance between L1 and L3 vertebral bodies. Demographics, vesicoureteral reflux grade, laterality, presence/absence of bladder-bowel dysfunction, and ureteral diameter ratio were tested in univariate and multivariable analyses. Primary outcome was breakthrough febrile urinary tract infections.

RESULTS

We analyzed 112 girls and 28 boys with a mean ± SD age of 2.5 ± 2.3 years at diagnosis. Vesicoureteral reflux was grade 1 to 2 in 64 patients (45.7%), grade 3 in 50 (35.7%), grade 4 in 16 (11.4%) and grade 5 in 10 (7.2%). Mean ± SD followup was 3.2 ± 2.7 years. A total of 40 children (28.6%) experienced breakthrough febrile urinary tract infections. Ureteral diameter ratio was significantly greater in children with (0.36) vs without (0.25) breakthrough febrile infections (p = 0.004). Controlling for vesicoureteral reflux grade, every 0.1 U increase in ureteral diameter ratio resulted in 1.7 times increased odds of breakthrough infection (95% CI 1.24 to 2.26, p <0.0001).

CONCLUSIONS

Children with increased distal ureteral diameter ratio are at greater risk for breakthrough febrile urinary tract infections independent of reflux grade. Ureteral diameter ratio provides valuable prognostic information about risk of recurrent pyelonephritis and may assist with clinical decision-making.

Vesicoureteral reflux and continuous prophylactic antibiotics

Vesicoureteral reflux (VUR) management must be tailored based on the risk for further infections and renal scarring, gender, likelihood of spontaneous resolution, and parental preferences. Because we now understand that sterile VUR is benign and most reflux spontaneously resolves over time, the initial approach in majority of children is non-surgical with continuous antibiotic prophylaxis (CAP) and correction of bladder and bowel dysfunction. Despite increasing utilization of CAP over the past four decades, the efficacy of antibiotic prophylaxis has been questioned due to conflicting results of studies plagued with design flaws and inadequate subject sample size. The Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) trial, which was designed to address many of the limitations from previous studies, provided much needed answers. In this review, we sought to describe the controversy surrounding VUR management, highlight the results of RIVUR trial, and discuss how the RIVUR findings impact our understanding of CAP in the management of VUR.