Utility of the distal ureteral diameter on VCUG for grading VUR

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.

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).

Does the distal ureteral diameter ratio (UDR) matter in the surgical management of vesicoureteral reflux in children?

PURPOSE

To evaluate UDR reliability, sensitivity, specificity and to identify the best treatment basing on UDR among single or double endoscopic injections and ureteral reimplantation.

METHODS

Data of patients affected by primary VUR and treated by endoscopic injection over a 10 years period were retrospectively analyzed. Two radiologist attributed reflux grade and UDR on voiding cystourethrogram twice and blinded. Follow-up focused on resolution after 1 or 2 endoscopic injections. Relation between UDR, reflux grade and outcomes were analyzed.

RESULTS

Patient enrolled were 198. Low grade VUR was present in 24.8%, grade 3 in 41.6%, grade 4-5 in 33.6%. Resolution after one injection was obtained in 88 patients; among 110 not resolved 104 cases had a second injection. Success after 2 injections was reported in 138 cases. UDR showed a higher reliability compared with reflux grade both in intra than inter-reader measurement (ICC > 90%). Success after 1 or 2 injections was reported for UDR < 0.33 and UDR < 0.47 respectively.

CONCLUSION

UDR shows to be a more reliable measurement that allows for an objective estimation of VUR severity and prognosis. It represents a quantitative parameter that might be useful to identify patients who may benefit endoscopic or surgical treatment, avoiding unnecessary under or over-treatment.

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.

The ureteral diameter ratio as a predictive factor in renal scarring associated with primary vesicoureteral reflux

INTRODUCTION

The ureteral diameter ratio (UDR) is reported to be effective in predicting the outcomes of vesicoureteral reflux (VUR) in several studies.

OBJECTIVE

The objective of the current study was to compare the risk of scarring in patients with VUR relative to UDR and the VUR grade. We also aimed to demonstrate other associated risk factors in scarring and investigate the long-term complications of VUR and their relationship with UDR.

STUDY DESIGN

Patients diagnosed with primary VUR were retrospectively enrolled in the study. UDR was calculated by dividing the largest ureteral diameter (UD) by the distance between L1-L3 vertebral bodies. Demographic and clinical data, laterality, VUR grade, UDR, delayed upper tract drainage on voiding cystourethrogram, recurrent urinary tract infections (UTI), and long-term complications of VUR were compared between the patients with and without renal scars.

RESULTS

A total of 127 patients and 177 renal units were included in the study. There was a significant difference between the patients with and without renal scars according to age at diagnosis, bilaterality, reflux grade, UDR, recurrent UTI, bladder bowel dysfunction, hypertension, decreased estimated glomerular filtration rate, and proteinuria. The logistic regression analysis revealed that UDR had the highest odds ratio among the factors affecting scarring in VUR.

DISCUSSION

VUR grading based on the evaluation of the upper urinary tract is one of the most important predictors for treatment options and prognosis. However, it is more likely to reflect ureterovesical junctional anatomy and function, which play a crucial role in the pathogenesis of VUR.

CONCLUSION

UDR measurement seems to be an objective method that can help clinicians predict renal scarring in patients with primary VUR.

The additive impact of the distal ureteral diameter ratio in predicting early breakthrough urinary tract infections in children with vesicoureteral reflux

INTRODUCTION

Many factors influence patient and provider decisions to surgically correct vesicoureteral reflux (VUR), including risk of breakthrough febrile urinary tract infections and likelihood of spontaneous resolution. Ureteral diameter ratio has been shown in several studies to be more predictive than reflux grade with regard to breakthrough urinary tract infection (UTI). We developed and investigated the accuracy of a computational model for predicating febrile breakthrough urinary tract infection within 13 months of starting prophylactic antibiotics in children with VUR.

OBJECTIVE

The aim of this study was to validate a model for evaluating the impact of distal ureteral diameter ratio (UDR) in predicting early breakthrough urinary tract infections in children with VUR.

STUDY DESIGN

Following a retrospective review, we recorded patient demographics, presenting symptoms, VUR grade, laterality, VUR during filling or voiding, initial bladder volume at the onset of VUR, ureteral duplication, voiding dysfunction, distal ureteral diameter ratio, and number of UTIs prior to VUR diagnosis. NeUROn++, a set of C++ programs, was used to model each data set using logistic regression and neural networks with different architectures.

RESULTS

After exclusions, 136 children (93 girls and 43 boys) diagnosed with primary VUR had detailed VCUG and UDR data available. Fourteen children (10.3%) experienced breakthrough febrile UTI events within 13 months of VUR diagnosis. There was a significant association with UDR and breakthrough UTI (p = 0.008). Various computational prediction models for the outcome of breakthrough UTI were developed and evaluated. The computational model that fit best was a model using all variables with an ROC of 0.802.

DISCUSSION AND CONCLUSIONS

Clinicians and parents often opt for intervention based on likelihood of spontaneous resolution of VUR as well as clinical course, thereby placing an emphasis on the ability to predict likelihood of breakthrough UTI infections. Our statistical analysis and prediction models further confirm UDR as an important variable predictive of breakthrough UTIs within the first 13 months of beginning prophylactic antibiotics. Furthermore, we developed a neural network model incorporating UDR and grade with an ability to yield the greatest accuracy of any breakthrough UTI predictive calculator to date at 80%.

Additional VCUG-related parameters for predicting the success of endoscopic injection in children with primary vesicoureteral reflux

INTRODUCTION AND OBJECTIVE

Prediction of vesicoureteral reflux (VUR) prognosis and decision for treatment are usually made according to the reflux grading classification. But the management of VUR is still controversial since there are difficulties in distinguishing reflux grade due to inter- and intra-observer variations. Previous studies have demonstrated that the distal ureteral diameter ratio (UDR) on voiding cystourethrography (VCUG) may be more predictive for clinical prognosis than reflux grade. We aimed to predict the success of endoscopic injection in primary VUR by creating new models that include other additional parameters (timing of reflux, delayed post-voiding contrast drainage of the upper urinary tract) as well as UDR.

STUDY DESIGN

A total of 200 patients aged 2-15 years with primary VUR undergoing endoscopic injection were retrospectively evaluated. Demographic and clinical data for a total of 248 renal units were recorded. Besides reflux grade and laterality, distal ureteral diameter, UDR, timing of reflux [early filling, late filling or voiding] and presence of contrast delay in upper tract drainage were also assessed on VCUG. According to the complete resolution of VUR on the control VCUG at the postoperative 3rd month, the renal units were divided into two main groups: successful (n = 171, 68.9%) and unresolved (n = 77, 31.1%) RESULTS: The failure rate of endoscopic injection was found to be 4.068 times greater with early filling reflux on VCUG, 3.076 times greater with UDR>0.24, 2.745 times greater with delayed contrast drainage of the upper urinary tract, 2.666 times greater with the presence of scar in DMSA, 2.493 times greater with bladder-bowel dysfunction and 2.341 times greater with febrile urinary tract infection. We also observed that a model in which all VCUG-related parameters were combined provided a better estimation of endoscopic injection outcomes compared to only the reflux grade (AUC: 0.903 vs. 0.604, respectively).

DISCUSSION

Distal ureteral dilatation is considered to be a more decisive factor for clinical outcomes of primary VUR rather than upper urinary tract dilatation since ureterovesical junction anatomy plays a more important role in primary VUR pathophysiology. Studies investigating new prediction models on this topic have recently become more popular. However, a consensus has not yet been achieved.

CONCLUSION

We consider that UDR level, the timing of reflux and delayed upper tract drainage on VCUG may be more predictive parameters of endoscopic injection success compared with reflux grade, and could facilitate selecting the best candidates for surgery.

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.

Can distal ureteral diameter measurement predict primary vesicoureteral reflux clinical outcome and success of endoscopic injection?

OBJECTIVE

The objective of the study was to evaluate the predictive value of distal ureteral diameter ratio (UDR) on outcome of primary vesicoureteral reflux (VUR) and reflux resolution after endoscopic injection.

PATIENTS AND METHODS

Three hundred eighty-three patients treated for primary VUR between January 2010 and October 2015 were retrospectively reviewed. The parameters analyzed were age at diagnosis, sex, grade and lateralite of VUR, complaints at admission (febrile urinary tract infection, antenatal hydronephrosis, family history),bladder-bowel dysfunction (urgency, incontinence, constipation), dimercaptosuccinic acid (DMSA) scintigraphy findings, follow-up period, clinical course (spontaneous resolution or surgical correction), time of spontaneous resolution, surgical treatment time and age, materials used for injection and success of endoscopic injection. Ureteral diameter ratio was calculated on the initial VCUG at the time of the diagnosis as the largest ureteral diameter within the false pelvis divided by the distance between L1-L3.The correlation between UDR, clinical outcome (spontaneous resolution/surgical correction) and success of endoscopic injection was evaluated by logistic regression analysis. To compare the effect of UDR and grade of reflux on spontaneous resolution, multivariate logistic regression analysis was performed in three models together with sex, age, resolution time, presence of febrile UTI and DMSA scan findings.

RESULTS

Three hundred eighty-three patients were enrolled. There was a strong correlation between UDR and grade of reflux (p < 0,0001). Ureteral diameter ratio was higher in patients whose complaints at admission were family history and febrile UTI, but this correlation was not statistically significant (p > 0.05). When the correlation between UDR and the DMSA scan findings was evaluated, UDR was found to be significantly higher in patients with moderate and severe scarring. Bladder-bowel dysfunction was present in 111 patients (28.9%). There was no significant correlation between BBD and UDR (p > 0.05). 62 patients showed spontaneous resolution in a median duration of 1.55 years. The predictive value of UDR for spontaneous resolution was more significant than grade (p < 0.001).There was no spontaneous resolution in patients with UDR over 0.45.321 patients underwent operation (248 endoscopic injection, 17 ureteroneocystostomy, 56 endoscopic injection+ureteroneocystostomy). When the predictive value of the reflux grade and UDR in the success rate of endoscopic correction was compared, UDR was shown to be significantly more predictive than the grade of reflux (p < 0.05). Ureteral diameter ratio was significantly higher in patients whose injection treatment was unsuccessful. Each 0.05 unit increase in UDR affected the success of endoscopic injection negatively (95% CI:<0.001-0.071).

CONCLUSION

Ureteral diameter ratio is an objective measurement of VUR and appears to be a new predictive tool for clinical outcome and success after endoscopic injection.

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.

Validation of the ureteral diameter ratio for predicting early spontaneous resolution of primary vesicoureteral reflux

INTRODUCTION AND OBJECTIVE

Management of primary vesicoureteral reflux (VUR) remains controversial, and reflux grade currently constitutes an important prognostic factor. Previous reports have demonstrated that distal ureteral diameter ratio (UDR) may be more predictive of outcome than vesicoureteral reflux (VUR) grade. We performed an external validation study in young children, evaluating early spontaneous resolution rates relative to reflux grade and UDR.

STUDY DESIGN

Voiding cystourethrograms (VCUGs) were reviewed. UDR was computed by measuring largest ureteral diameter within the pelvis and dividing by the distance between the L1 and L3 vertebral bodies (Figure). VUR grade and UDR were tested in univariate and multivariable analyses. Primary outcome was status of VUR at last clinical follow-up (i.e. resolution, persistence, or surgical intervention). Demographics, VUR timing, laterality, and imaging indication were also assessed.

RESULTS

One-hundred and forty-seven children (98 girls, 49 boys) were diagnosed with primary VUR at a mean age of 5.5 ± 4.7 months. Sixty-seven (45.6%) resolved spontaneously, 55 (37.4%) had persistent disease, and 25 (17%) were surgically corrected. Patients who spontaneously resolved had significantly lower VUR grade, refluxed later during bladder filling, and had significantly lower UDR. In a multivariable model, grade of VUR (p = 0.001), age <12 months (p = 0.008), ureteral diameter (p = 0.02), and UDR (p < 0.0001) achieved statistical significance. For every 0.1 unit increase in UDR, there was a 2.6 (95% CI 1.58-4.44) increased odds of persistent VUR, whereas a 1.6 (95% CI 0.9-3.0) increased odds was observed for every unit increase in grade.

DISCUSSION

Both grade of reflux and UDR were statistically significant in a multivariable model; however, UDR had a higher likelihood ratio and was more predictive of early spontaneous resolution than grade alone. Furthermore, unlike traditional VUR grading where children with grade 1-5 may outgrow reflux depending on other factors, there appears to be a consistent UDR cutoff whereby patients are unlikely to resolve. In the present study, no child with a UDR greater than 0.43 experienced early spontaneous resolution, and only three (4.5%) of those with spontaneous resolution had a UDR above 0.35.

CONCLUSIONS

UDR correlates with reflux grade, and is predictive of early resolution in children with primary VUR. UDR is an objective measurement of VUR, and provides valuable prognostic information about spontaneous resolution, facilitating more individualized patient care.

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.

Imaging studies and biomarkers to detect clinically meaningful vesicoureteral reflux

The work-up of a febrile urinary tract infection is generally performed to detect vesicoureteral reflux (VUR) and its possible complications. The imaging modalities most commonly used for this purpose are renal-bladder ultrasound, voiding cystourethrogram and dimercapto-succinic acid scan. These studies each contribute valuable information, but carry individual benefits and limitations that may impact their efficacy. Biochemical markers are not commonly used in pediatric urology to diagnose or differentiate high-risk disease, but this is the emerging frontier, which will hopefully change our approach to VUR in the future. As it becomes more apparent that there is tremendous clinical variation within grades of VUR, the need to distinguish clinically significant from insignificant disease grows. The unfortunate truth about VUR is that recommendations for treatment may be inconsistent. Nuances in clinical decision-making will always exist, but opinions for medical versus surgical intervention should be more standardized, based on risk of injury to the kidney.

Inter-rater reliability of distal ureteral diameter ratio compared to grade of VUR

INTRODUCTION AND OBJECTIVE

Management of vesicoureteral reflux (VUR) remains controversial, and reflux grade constitutes an important prognostic factor. Recent work has suggested that distal ureteral diameter ratio (UDR) is a predictive factor relative to clinical outcome independent of grade. Previous studies have noted significant inter-rater variability with grading of VUR. The present study compared inter-rater reliability of reflux grade and UDR in children with primary VUR.

STUDY DESIGN

Four pediatric urologists independently reviewed, in a blinded fashion, voiding cystourethrograms. For each renal unit, grade was assigned according to the standardized international scale. The UDR was calculated by dividing the largest ureteral diameter within the false pelvis by the distance between L1-L3 vertebral bodies. Correlation within each rater was determined using Pearson's correlation coefficient. Reliability of VUR grade and UDR were calculated using two-way ANOVA model inter-rater agreement.

RESULTS

Four independent raters reliably measured VUR grade (ICC = 0.87, 95% CI = 0.78-0.93) and UDR (ICC = 0.95, 95% CI = 0.92-0.97). While UDR and grade were equally reliable measures, UDR had a tighter confidence interval. For each rater, grade and UDR were well correlated (r = 0.73-0.84; P < 0.0001). For higher-grade reflux, grade was more variable than UDR (Summary Figure). Using empirical thresholds, the increased variability of grade compared with UDR may lead to significant differences in clinical decision-making among physicians (P = 0.022).

DISCUSSION

Known discordance with grading reflux emphasizes the need for a more objective VUR measurement, as clinicians and parents often opt for clinical intervention based on both clinical course and the likelihood of spontaneous resolution. While ICC for UDR and grade were not significantly different, the confidence intervals for grade were wider due to greater variability among grade measurements. This suggests that using UDR measurements may lead to more accurate characterization of VUR and ultimately more consistent clinical decision-making across providers.

CONCLUSIONS

Ureteral diameter ratio has good inter-rater reliability among pediatric urologists, with less clinically relevant variability than VUR grade. Ureteral diameter ratio is a more objective and reliable measure than grade, and may be more useful in clinical decision-making.