External validation and reliability assessment of posterior urethral morphology on initial voiding cystourethrogram as a predictor for infants with posterior urethral valves

INTRODUCTION

The morphology of the bladder and posterior urethra on initial voiding cystourethrogram (VCUG) in posterior urethral valve (PUV) has been proposed as a meaningful early metric for short- and long-term kidney outcomes. Here, we seek to externally validate the proposed association and assess the reliability of PUV morphology characteristics.

MATERIALS AND METHODS

We reviewed our institutional database for patients managed for PUV between 2000 and 2022 and included those treated with primary ablation with at least 1 year of follow-up for kidney function. Each VCUG was evaluated by three independent raters for the height-width ratio of the bladder (HW-B), height-width ratio of the posterior urethra (HW-PU), and posterior-anterior urethral ratio (PA-UR), and trabeculation (none, fine, or coarse). We assessed the reliability in these with intra-class coefficient and Fleiss kappa for continuous and categorical data, respectively. We performed univariate analysis with nadir creatinine and five-year follow-up glomerular filtration rate (GFR).

RESULTS

In total, 98 patients met inclusion criteria. The median age at diagnosis and ablation was 10 and 21 days, respectively. Patients with nadir creatinine <0.8 mg/dL had higher follow-up GFR (101 vs. 20 ml/min/1.73 m2, p = 0.04), and lower risk of CKD (odds ratio 14.7, p = 0.002). The median value for HW-B was 1.4, median HW-PU was 2.1, and median PA-U was 4.7, There was significant inter-class agreement between all three measures of 0.80, 0.51, and 0.70 (p < 0.001). The inter-rater agreement for bladder trabeculation was fair (Fleiss K = 0.40, p < 0.001). There was no statistically significant correlation between HW-B, HW-PU, PU-A with nadir creatinine (p = 0.07, 0.33, 0.91) or 5-year GFR (0.27, 0.45, 0.62), respectively.

DISCUSSION

There is significant interest in determining prognostic factors and metrics in PUV. The morphological characteristics on VCUG are reliable and is available information for all boys diagnosed with PUV, resulting in an attractive metric. While we do not demonstrate correlation with kidney outcomes, VCUG features warrant further attention as prognostic factors in PUV.

CONCLUSIONS

PUV morphology on initial VCUG is a reliable metric of lower urinary tract deformity but is not associated with 5-year kidney outcomes.

[Imaging in children and adolescents with urinary tract infections]

CLINICAL/METHODOLOGICAL PROBLEM

Urinary tract infections are among the most common infectious diseases in childhood. The task of imaging is to detect predisposing factors, such as urinary transport disorders, vesicoureteral reflux, as well as complications such as abscesses or pyonephrosis in addition to possible morphological changes of the kidneys and the draining urinary tract during an infection.

STANDARD RADIOLOGICAL PROCEDURES

The initial diagnostic imaging technique is generally sonography. For the diagnosis of vesicoureteral reflux, voiding urosonography or alternatively radiological voiding cystourethrography are used. Further diagnostic workup may include scintigraphy, magnetic resonance imaging (MRI) or, in exceptional cases, computed tomography (CT).

RECOMMENDATION FOR PRACTICE

In children and adolescents, it is of particular importance to avoid recurrent urinary tract infections and their sequelae. This requires precise imaging diagnostics, which must be performed with special consideration of radiation protection.

Culture-positive urinary tract infection following micturating cystourethrogram in children

Objective

To determine the incidence of culture-positive urinary tract infection (UTI) after micturating cystourethrogram (MCUG). We further wanted to identify risk factors for developing a culture-positive UTI following MCUG.

Methods

A retrospective review of the available medical records of 500 paediatric patients who underwent MCUG in Perth, Western Australia was performed.

Results

Seven (1.4%) patients comprised of four females and three males developed a febrile, culture-positive UTI within 14 days following MCUG. Significant association was found for female patients, patients with neurogenic bladder, and patients with previous culture-positive UTI as developing a culture-positive UTI following MCUG. Multivariate logistic regression determined that patients were more likely to develop culture-positive UTI within 14 days following MCUG if they had a known history of UTI (odds ratio: 5.0, 95% confidence interval: 1.5–17.3, p=0.010) or had a neurogenic bladder (odds ratio: 4.2, 95% confidence interval: 1.0–17.9, p=0.049).

Conclusion

The incidence of patients who developed a febrile, culture-positive UTI following MCUG was low at 1.4%. Statistically significant and independent associations for the development of culture positive UTI were found in patients with neurogenic bladder and patients with previous culture-positive UTI. Further prospective studies are necessary to determine necessity of prophylactic antibiotics for high-risk patients, e.g., patients with neurogenic bladder or previous culture-positive UTI.

Voiding cystourethrogram: Who gets a cyclic study and does it matter?

BACKGROUND

Voiding cystourethrogram (VCUG) images the urethra and bladder during both bladder filling and emptying, as well as the ureters and kidneys when vesicoureteral reflux (VUR) is present. Given the variation in VCUG technique and reporting, the American Academy of Pediatrics Sections on Urology and Radiology published a joint standardized VCUG protocol in 2016, which included the recommendation of at least 2 voiding cycles to identify intermittent VUR and/or ureteral ectopia.

STUDY DESIGN

VCUG were assessed for adherence to performance of cyclic study. Children who underwent cyclic evaluation were compared to those who underwent a single cycle VCUG. Radiation dosage was also analyzed. Studies performed on patients >18 years of age and those obtained as part of a trauma evaluation were excluded from study.

RESULTS

Two hundred and eighty-four VCUGs were analyzed, 97 (34.2%) were positive for VUR on the initial cycle. Of the remaining 187 studies, 116 (62%) had multiple filling-voiding cycles while in 71 (38%) only a single cycle was performed. One hundred and sixty-one (86.1%) were negative for vesicoureteral reflux. Twenty-six (13.9%) children were diagnosed with VUR after the initial filling-voiding cycle: 6 were diagnosed with grade I, 2 grade II, 11 grade III, 2 grade IV and 5 grade V. Of the 123 total children found to have VUR, 26 (21.2%) were diagnosed after an initial negative cycle. Younger children were significantly more likely to have a cyclic study performed; mean age of patients undergoing a cyclic study was 1.09 ± 2.16 years versus 3.86 ± 4.5 years (p ≤ 0.0001). Categorically, 74.1% of children less than 1 year of age underwent a cyclic study compared to 6.9% of children older than 5 years of age (p ≤ 0.0001). There was no difference based on sex with 49.1% of males and 50.9% of females (p = 0.667) undergoing cyclic evaluation. Children undergoing a cyclic study had lower median radiation dose 2.15 microGy m2 (range 0.09-111) compared to 4.41 (range 1.3-104) [p = 0.01].

DISCUSSION

Vesicoureteral reflux may occur intermittently and cyclic VCUG is thought to enhance the ability to detect reflux. In our cohort, 26 children (9.2%) were only diagnosed after an additional cycle - ie 21.1% of reflux would have been missed had a cyclic study not been performed. The majority of these patients (69.2%, 18 of 26) were found to have dilating, and thus perhaps more clinically significant, reflux. Our study highlights the importance of obtaining as much information as possible and adhering to the standardized VCUG protocol.

CONCLUSION

Younger children are more likely to undergo cyclic VCUG. While most reflux is detected with the initial filling-voiding cycle, 26 (21.2%) patients were diagnosed after an initial negative cycle with the majority being dilating VUR.

Contemporary Management of Urinary Tract Infections in Children

Purpose of Review

Urinary tract infection (UTI) in children is a major source of office visits and healthcare expenditure. Research into the diagnosis, treatment, and prophylaxis of UTI has evolved over the past 10 years. The development of new imaging techniques and UTI screening tools has improved our diagnostic accuracy tremendously. Identifying who to treat is imperative as the increase in multi-drug-resistant organisms has emphasized the need for antibiotic stewardship. This review covers the contemporary management of children with UTI and the data-driven paradigm shifts that have been implemented into clinical practice.

Recent Findings

With recent data illustrating the self-limiting nature and low prevalence of clinically significant vesicoureteral reflux (VUR), investigational imaging in children has become increasingly less frequent. Contrast-enhanced voiding urosonogram (CEVUS) has emerged as a useful diagnostic tool, as it can provide accurate detection of VUR without the need of radiation. The urinary and intestinal microbiomes are being investigated as potential therapeutic drug targets, as children with recurrent UTIs have significant alterations in bacterial proliferation. Use of adjunctive corticosteroids in children with pyelonephritis may decrease the risk of renal scarring and progressive renal insufficiency. The development of a vaccine against an antigen present on Escherichia coli may change the way we treat children with recurrent UTIs.

Summary

The American Academy of Pediatrics defines a UTI as the presence of at least 50,000 CFU/mL of a single uropathogen obtained by bladder catheterization with a dipstick urinalysis positive for leukocyte esterase (LE) or WBC present on urine microscopy. UTIs are more common in females, with uncircumcised males having the highest risk in the first year of life. E. coli is the most frequently cultured organism in UTI diagnoses and multi-drug-resistant strains are becoming more common. Diagnosis should be confirmed with an uncontaminated urine specimen, obtained from mid-stream collection, bladder catheterization, or suprapubic aspiration. Patients meeting criteria for imaging should undergo a renal and bladder ultrasound, with further investigational imaging based on results of ultrasound or clinical history. Continuous antibiotic prophylaxis is controversial; however, evidence shows patients with high-grade VUR and bladder and bowel dysfunction retain the most benefit. Open surgical repair of reflux is the gold standard for patients who fail medical management with endoscopic approaches available for select populations.

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.

Beyond reflux: the spectrum of voiding cystourethrogram findings in the pediatric population

Voiding cystourethrography (VCUG) is a widely accepted radiographic imaging technique that has been traditionally used for identifying vesicoureteral reflux in children. Given the simultaneous evaluation of the lower urinary tract that is afforded by VCUG, many common and uncommon abnormalities of the ureters, bladder and urethra can also be elucidated. Knowledge of the appearance of these urological entities may facilitate their proper identification.

Prospective evaluation of radiation dose with conventional fluoroscopic voiding cystourethrogram in pediatric patients

INTRODUCTION

Skin entrance doses for voiding cystourethrogram (VCUG) have not been well characterized in the literature. Radiation exposure is measured as either dose area product (DAP) or air kerma, which estimates the effective dose, but does not accurately reflect absorbed dose at skin level.

OBJECTIVE

The objective of this study was to measure the skin entrance dose during fluoroscopic VCUG study in pediatric patients using single point dosimeters.

STUDY DESIGN

Pediatric patients undergoing fluoroscopic VCUG were prospectively enrolled in our study. Landauer NanoDot™OSLD dosimeters were affixed to the skin overlying the sacrum to measure skin entrance dose. The fluoroscopic unit was set to the following parameters: low dose setting, skin-to-source distance of 54 cm, pulsed fluoroscopy at 3 frames/sec.

RESULTS

Forty-four patients with a median age of 13.6 months (IQR 3.7-42.3) were enrolled. Median fluoroscopic time was 54 s (IQR 36-72). The median values absorbed dose by dosimeter and air kerma were 0.32 mGy (IQR 0.13-0.56, range 0.01-2.9) and 0.24 mGy (IQR 0.14-0.37), respectively. There was a positive correlation between the air kerma and absorbed dose (r = 0.69, p < 0.001) and fluoroscopy time and absorbed dose mGy (r = 0.60, p < 0.001). Absorbed dose was independent of age, body mass index and body surface area (p = 0.19, p = 0.57 and p = 0.16, respectively). Median whole body effective dose was 0.04 mSv (IQR 0.02-0.7).

DISCUSSION

Overall, the absorbed dose received by the dosimeter remained low at a median of 0.32 mGy (range 0.01-2.91). These values are remarkably low and well within the accepted radiation exposure norms. Our radiologists follow a strict protocol to reduce the overall radiation emitted during a VCUG. These measures include setting the x-ray source at a low dose mode, collimating to the smallest area possible, and using pulsed fluoroscopy at 3 frames/sec. Limitations to this study include a slight variability in technique of VCUG between different technicians and providers, for which we cannot control.

CONCLUSION

The radiation dose absorbed at the skin entrance and uniform whole body effective dose is low for a single VCUG when utilizing strict parameters. While newer non-ionizing technologies continue to emerge, our data is encouraging and will serve as a valuable tool when educating parents regarding radiation doses associated with a VCUG.

Bladder prolapse through a patent urachus presenting as an umbilical mass in the newborn: characteristic prenatal sonographic findings and the diagnostic benefit of postnatal cystography

Bladder prolapse through a patent urachus is rare. We present a newborn with an unusual exophytic, erythematous umbilical mass. Voiding cystography readily demonstrated continuity of the bladder dome with the umbilical mass, confirming bladder prolapse through a patent urachus. The diagnosis of bladder prolapse was rapidly made in a second newborn with similar imaging and clinical findings and confirmed by cystography. We discuss the embryology of this condition including the association with a vesico-allantoic cyst in utero. Pre- and postnatal images are presented. The use of cystography in diagnosis is emphasized.

Feasibility study of a novel portable digital radiography system modified for fluoroscopy in the neonatal intensive care unit

BACKGROUND

A portable radiographic system capable of fluoroscopic imaging in the neonatal intensive care unit (NICU) potentially benefits critically ill neonates by eliminating the need to transport them to a fluoroscopy suite.

OBJECTIVE

To evaluate whether a portable bedside fluoroscopy system in the NICU can deliver comparable image quality at a similar dose rate to a standard system in a fluoroscopy suite.

MATERIALS AND METHODS

In phase A, 20 patients <3 years of age and scheduled to undergo upper gastrointestinal series (upper GI) or voiding cystourethrograms (VCUG) in the radiology fluoroscopy suite were recruited to evaluate a portable fluoroscopic unit. A modified portable radiographic system with a cassette-sized detector and an in-room fluoroscopy system were sequentially used in the same examination. Four radiologists compared the image quality of 20 images from each system using the Radlex score (1-4) for five image quality attributes. The radiation dose rates for the portable and in-suite systems were collected. In phase B, fluoroscopy studies were performed in 5 neonates in the NICU and compared to the 20 previous neonatal studies performed in the department. Clinical workflow, examination time, fluoroscopy time, scattered radiation dose and patient radiation dose were evaluated.

RESULTS

In phase A, average dose rates for in-room and portable systems were equivalent, (0.322 mGy/min and 0.320 mGy/min, respectively). Reader-averaged Radlex scores for in-room and portable systems were statistically significantly greater (P<0.05) for all attributes on the portable system except for image contrast. In phase B, scattered radiation from the average fluoroscopy time (26 s) was equivalent to the scattered radiation of 2.6 portable neonatal chest radiographs. Procedure time and diagnostic quality were deemed equivalent. The average dose rate in the NICU with the portable system was 0.21 mGy/min compared to 0.29 mGy/min for the in-room system.

CONCLUSION

The portable fluoroscopy unit is capable of providing comparable image quality at equivalent dose levels to an in-room system for neonates with minimal risks to the staff and other patients in the NICU.

Accuracy of pre-operative fistula diagnostics in anorectal malformations

Background

Surgical safety during posterior sagittal anorectal plasty (PSARP) for anorectal malformations (ARM) depends on accurate pre-operative fistula localization. This study aimed to evaluate accuracy of pre-operative fistula diagnostics.

Methods

Ethical approval was obtained. Diagnostic accuracy of pre-PSARP symptoms (stool in urine, urine in passive ostomy, urinary tract infection) and examination modalities (voiding cystourethrogram (VCUG), high-pressure colostogram, cystoscopy and ostomy endoscopy) were compared to final intra-operative ARM-type classification in all male neonates born with ARM without a perineal fistula treated at a tertiary pediatric surgery center during 2001–2020.

Results

The 38 included neonates underwent reconstruction surgery through PSARP with diverted ostomy. Thirty-one (82%) had a recto-urinary tract fistula and seven (18%) no fistula. Ostomy endoscopy yielded the highest diagnostic accuracy for fistula presence (22 correctly classified/24 examined cases; 92%), and pre-operative symptoms the lowest (21/38; 55%). For pre-operative fistula level determination, cystoscopy yielded the highest diagnostic accuracy (14/20; 70%), followed by colostogram (23/35; 66%), and VCUG (21/36; 58%). No modality proved to be statistically superior to any other.

Conclusions

Ostomy endoscopy has the highest diagnostic accuracy for fistula presence, and cystoscopy and high-pressure colostogram for fistula level determination. Correct pre-operative ARM-typing reached a maximum of 60–70%.

Are anterior urethral valve and anterior urethral diverticulum two separate entities: A radiological and endoscopic review

BACKGROUND

Anterior urethral valve (AUV) and anterior urethral diverticulum (AUD) are two rare causes of anterior urethral obstruction with variable presentation and anatomy. Their existence as the same or different entity is still debatable, and management has not yet been standardized.

OBJECTIVE

This study is a retrospective review of cases diagnosed with anterior urethral obstruction and correlation of radiological and endoscopic anatomy of AUV and AUD.

STUDY DESIGN

A retrospective review of cases diagnosed with AUV and AUD, between May 2013 and February 2020 is presented. The presentation, laboratory, radiological and endoscopic anatomy along with the management required was reviewed. A special emphasis has been given on the correlation of radiological and endoscopic anatomy and an attempt has been made to standardize the management.

RESULTS

A total of 8 patients with age ranging from 2 months to 9 years were reviewed. Poor urinary stream and recurrent UTI was the commonest presentation. The anatomy of the anterior urethra on VCUG (voiding cystourethrogram) and Urethrocystoscopy was correlated. Two sets of patients were identified. In the first set, five cases on endoscopy had findings of the classical valve-like fold in the anterior urethra with immediate proximal dilation of the urethra giving the appearance of a 'pseudodiverticula' without any definite opening. In three of these cases, endoscopic findings correlated well with radiological findings of 'pseudodiverticula' in which dilated proximal urethra formed an obtuse angle with the ventral floor of the urethra. The other set of four patients had a 'true diverticula' on endoscopy with a well-defined mouth and prominent distal lip, correlating well with radiological findings of a 'true diverticula' forming an acute angle with the ventral floor of the urethra. One case on endoscopy had both an anterior urethral valve with a proximal 'pseudodiverticula and a large wide-mouthed bulbar 'true diverticula'. All the patients with classical valves were successfully treated using a resectoscope while two patients with 'true diverticula' were successfully managed by incising the distal lip. One of the patients previously managed for the posterior urethral valve (PUV) had both classical valves in the anterior urethra with proximal 'pseudodiverticula' and a bulbar 'true diverticula'. The AUV was ablated with a resectoscope while 'true diverticula' required diverticulectomy. All the patients after follow up of 3 months-8 years, were asymptomatic except the one with 'true diverticulum' who remained symptomatic after TUR (Trans-urethral resection) and required vesicostomy.

DISCUSSION

AUV and AUD both can cause obstructive uropathy. The proximal dilatation related to AUV cannot be labeled as a 'true diverticula', which lacks a classical orifice. The distal obstructing lip of 'true diverticula' should not be confused with a classical mucosal valve-like fold seen in AUV. While AUV and small AUD can be treated with endoscopic ablation, large diverticula as a result of wide spongiosal defects require surgical excision. A good understanding of their radiological and endoscopic anatomy is required to differentiate them and decide for appropriate management.

CONCLUSION

Based on our experience, AUV and AUD should be differentiated and should be considered as two separate entities.

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.

Standardized protocol for voiding cystourethrogram: Are recommendations being followed?

BACKGROUND

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

DISCUSSION

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

CONCLUSION

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

Can the posterior:anterior urethral ratio on voiding cystourethrogram be used as a reliable predictor of successful posterior urethral valve ablation in male children?

Background

The role of the voiding cystourethrogram (VCUG) in the follow-up of children with posterior urethral valves (PUVs) post-ablation has been considered a standard practice. The urethral ratio and gradient of change have proven to be useful.

Objectives

We aimed to review the role of the ‘ideal’ ratio on predicting residual PUV post-ablation.

Methods

A systematic review of the PubMed, SCOPUS and Web of Science databases was performed (April 2019). The search terms included ‘Urethral Ratio and Posterior urethral valve ablation’. All cited reference lists were further evaluated for additional inclusive studies.

Results

Eleven studies were identified, of which nine were relevant to the topic. Case reports, comments and adult and animal studies were excluded, leaving four studies for critical review. In total, 338 patients were assessed. The control group consisted of 167 age-matched, male children. Study regions included India and Australia. The ages ranged from 15 days to 3.4 years. Ablation methods included the use of a resectoscope with cutting diathermy, cold knife or Bugbee electrode. The mean urethral ratios in the control group ranged from 1.04 to 1.73. The suggested predictive urethral cut-off ratios recommended include 2.2 (p = 0.001), 2.5–3 and 3.5.

Conclusion

Although the precise cut-off ratio could not be clearly defined in this review, a urethral ratio less than a range of 2.2–3.5 has proven to be a beneficial predictor of ablation success and should thus be incorporated into standard VCUG reporting templates in the follow-up of PUVs in male children in resource-limited settings.

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

BACKGROUND

Bladder volume at the onset of vesicoureteral reflux (VUR) is an important prognostic indicator of spontaneous resolution and the risk of pyelonephritis.

OBJECTIVE

We aim to determine whether pediatric urologists and pediatric radiologists can accurately estimate the timing of reflux by examining voiding cystourethrogram (VCUG) images without prior knowledge of the instilled contrast volume.

MATERIALS AND METHODS

Total bladder volume and the volume at the time of reflux were collected from VCUG reports to determine the volume at the onset of VUR. Thirty-nine patients were sorted into three groups: early-/mid-filling reflux, late-filling and voiding only. Thirty-nine images were shown to three pediatric urologists and two pediatric radiologists in a blinded fashion and they were then asked to estimate VUR timing based on the above categories. A weighted kappa statistic was calculated to assess rater agreement with the gold standard volume-based report of VUR timing.

RESULTS

The mean patient age at VCUG was 3.1±2.9 months, the median VUR was grade 3, and 20 patients were female. Overall agreement among all five raters was moderate (k=0.43, 95% confidence interval [CI] 0.36-0.50). Individual agreement between rater and gold standard was slight to moderate with kappa values ranging from 0.13 to 0.43.

CONCLUSION

Pediatric radiologists and urologists are unable to accurately and reliably characterize VUR timing on fluoroscopic VCUG. These findings support the recently published American Academy of Pediatrics protocol recommending the routine recording of bladder volume at the onset of VUR as a standard component of all VCUGs to assist in a more accurate assessment of the likelihood of resolution and risk of recurrent urinary tract infections.

Urethrovaginal Fistula: A Rare Complication Secondary To Impacted Foreign Body In Vagina

We report a case of urethrovaginal fistula following impacted foreign body in vagina. Fistula was suspected on the basis of history and examination and was later on confirmed by voiding cystourethrogram. Cystourethroscopy was done and the fistula was repaired transvaginally in layers. We are reporting this case because of its rarity.

Supine magnetic resonance defecography for evaluation of anterior compartment prolapse: Comparison with upright voiding cystourethrogram

PURPOSE

To compare utility of supine Magnetic Resonance Defecography (MRD) with upright Voiding Cystourethrogram (VCUG) for evaluation of cystocele and urethral hypermobility (UHM).

METHODS

This was an IRB-approved, HIPAA-compliant, retrospective study of 51 consecutive patients with symptomatic pelvic organ prolapse (POP) and lower urinary tract symptoms who underwent both upright VCUG and supine MRD. Cystocele height was defined in centimeters with reference to the inferior edge of the pubic bone on VCUG and the pubococcygeal line on MRD. Urethral angle at rest (UAR) and during straining (UAS) was measured in degrees between the urethral axis and a vertical line at the external meatus. Pairedt-test and simple linear regression were applied to compare VCUG and MRD data sets. p <  0.05 was considered significant.

RESULTS

The mean cystocele extent was 1.58 cm lower (more inferior to the reference point) (95% CI for the mean difference: 1.21, 1.94;p < 0.0001) on MRD (-2.73 ± 1.99 cm) than on VCUG (-1.16 ± 1.75 cm). Mean UAS on MRD (72.29 ± 26.45) was 31.8 degrees higher compared to that on VCUG (40.45 ± 21.41), (95% CI for mean difference in UAS: 37.57, 26.11; p < 0.0001). Mean UAS-UAR on MRD (74.30 ± 28.50) was 58.6 degrees higher compared to that on VCUG (15.70 ± 11.27) (95% CI for mean difference in UAS-UAR 65.94, 51.26; p < 0.0001). Cystocele size was upgraded in 22 (43.3%) patients on MRD compared to VCUG. Five (9.8%) patients demonstrated UHM on VCUG; 48 (94.1%) patients demonstrated UHM on MRD. The differences between VCUG and MRD scores persisted across the range of VCUG measurements. Cystocele size was significantly larger in POP (+) patients than in POP (-) patients on MRD (p =  0.005) but not on VCUG (p =  0.06).

CONCLUSIONS

Supine MRD demonstrates significantly higher prevalence and degree of cystocele and UHM than upright VCUG, and alters the grade of bladder prolapse in a significant portion of the patient population. Cystocele size on MRD correlates with clinical presence of prolapse symptoms.

Comparison of diagnostic accuracy for fistulae at ultrasound and voiding cystourethrogram in neonates with anorectal malformation

BACKGROUND

Recently, it has been reported that anorectal malformation with rectourethral fistula in male neonates can be managed by primary neonatal reconstruction without colostomy. To prevent urethral injury during anorectoplasty, the fistula's location is important. To date, the use of voiding cystourethrograms to determine the presence and location of fistulas in neonates with anorectal malformations has not been studied.

OBJECTIVE

To compare the accuracy of ultrasound (US) and voiding cystourethrogram for determining the presence and location of fistulas in neonates with anorectal malformation.

MATERIALS AND METHODS

We included 21 male neonates with anorectal malformation with rectourethral fistula (n=16), rectovesical fistula (n=1) or no fistula (n=4) who underwent US and voiding cystourethrogram preoperatively on the day of surgery. Fistula imaging was classified into three grades (0-2), and grades 1-2 were considered fistula positive. We compared the imaging-based location of the fistula with surgical findings.

RESULTS

US performed significantly better than voiding cystourethrogram for determining the presence of fistulas (area under the receiver operating characteristic curve, 0.90 vs. 0.71, respectively; P=0.044) (diagnostic accuracy 85.7%, 95% confidence interval [95% CI] 63.7-97.0% and 52.4%, 95% CI 29.8-74.3%, respectively). In cases with fistulas detected by either modality, the accuracy of locating the fistula by US was 50.0% (95% CI 24.7-75.3%) and by voiding cystourethrogram was 100% (95% CI: 59.0-100%).

CONCLUSION

US accurately detected, but did not accurately locate, fistulas in neonates with anorectal malformation. When planning primary neonatal reconstruction of anorectal malformation without colostomy, voiding cystourethrogram could provide additional information about fistula location.

Knowledge of vesicoureteral reflux obtained by screening voiding cystourethrogram in children with multicystic dysplastic kidney does not change patient management or prevent febrile urinary tract infection

INTRODUCTION

While children with multicystic dysplastic kidneys (MCDK) are predisposed to contralateral kidney (CK) vesicoureteral reflux (VUR), it is unknown if this results in an increased risk of urinary tract infection (UTI). The authors hypothesized that knowledge of VUR via voiding cystourethrogram (VCUG) would enable altered practices to prevent UTI and thus reduce the number of febrile urinary tract infections (fUTIs).

METHODS

The authors performed a retrospective chart review of all patients at their institution of multiple providers caring for patients with a diagnosis of MCDK from 1/1/07 to 7/14/17. Patients were evaluated for age, sex, circumcision status, race, imaging results on renal ultrasound (RUS) and/or VCUG, occurrence of fUTI, and prophylactic antibiotic (ppx) use.

RESULTS

One hundred sixty-five patients were identified; 70% of patients were diagnosed with MCDK on prenatal imaging. Seventy-seven (47%) patients had a screening VCUG after diagnosis of MCDK. Eighteen patients with VCUG had VUR with 13 (17%) having VUR in the CK. Only children undergoing VCUG were placed on ppx with no difference in the use of ppx in patients with and without dilating VUR (45% vs 43%; p = 0.91). Overall, 11 patients experienced a fUTI. There was no significant difference in fUTI between those children who underwent VCUG compared with those who did not (10% vs 3%; p = 0.07). Use of ppx and presence of CK renal anomaly on RUS had no impact on incidence of subsequent fUTI.

CONCLUSION

Knowledge of VUR based on VCUG results did not reduce the rate of fUTI or predict ppx use in the practice of multiple providers. The authors feel this confirms the low utility of VCUG in the practical management of otherwise healthy children with MCDK.

Renal tubular markers as screening tools for severe vesicoureteral reflux

Severe (grades IV and V) vesicoureteral reflux (VUR) is a risk factor for acute pyelonephritis, renal scars, and renal failure. This study evaluates albumin and N-acetylglucosaminidase (NAG) urinary excretion, and renal concentrating ability as screening tools to select patients for voiding cystourethrogram (VCUG). Children (111 M, 52 F) aged 10.97 ± 21.17 months (mean + SD), diagnosed with UTI, and who had undergone renal ultrasound and a VCUG, underwent a desmopressin test and had albumin/creatinine and NAG/creatinine urinary excretion measured. Urine osmolality was significantly lower in 27 children with severe VUR (375.3 ± 171.8 mOsm/kg; mean + SD) compared to 100 patients with normal VCUG (611.5 ± 175.8 mOsm/kg), p < 0.001, and to 36 patients with VUR grades I to III (636.2 ± 180.2 mOsm/kg), p < 0.001. NAG/creatinine ratio was significantly elevated in 20 children with severe VUR (26.4 (28.3) U/g); median and interquartile range compared to 67 children with normal VCUG (10.8 (17.9) U/g), p = 0.003, and to 20 patients with VUR grades I to III (7.6 (21.1) U/g), p = 0.009.Conclusions: Urinary osmolality is significantly decreased and urinary excretion of NAG is significantly increased in patients with severe VUR. These tests could select patients for VCUG to assess for severe VUR. What is Known: • Severe vesicoureteral reflux (SVUR) may contribute to renal damage. Severe vesicoureteral reflux is diagnosed by voiding cystourethrogram and represents about 10% of all patients with VUR. Currently, there are no reliable tests used prior to VCUG to help on the decision of obtaining a VCUG to diagnose SVUR. What is New: • This study shows that renal tubular markers (concentrating ability and N-acetylglucosaminidase (NAG) excretion) are useful tests prior to voiding cystourethrogram to screen for severe vesicoureteral reflux. • This study suggests the use of renal concentrating ability and urinary N-acetylglucosaminidase (NAG) excretion to screen for severe vesicoureteral reflux before requesting a voiding cystourethrogram.

Population-based trend analysis of voiding cystourethrogram ordering practices in a single-payer healthcare system before and after the release of evaluation guidelines

INTRODUCTION

While voiding cystourethrogram (VCUG) is a widely-accepted test, it is invasive and associated with radiation exposure. Most cases of primary vesicoureteral reflux (VUR) are low-grade and unlikely to be associated with acquired renal scarring. To select patients at greatest risk, in 2011 the American Academy of Pediatrics (AAP) published guidelines for evaluation of children ages 2 - 24 months with urinary tract infections (UTIs). Similarly, in 2010 the Society for Fetal Urology (SFU) published guidelines for patients with hydronephrosis. Herein a prospectively-collected database was queried through the Institute of Clinical Evaluative Sciences (ICES), exploring trends in VCUG ordering within the Ontario Health Insurance Program (OHIP), which guarantees universal access to care.

MATERIAL AND METHODS

A dedicated ICES analyst extracted data on all patients younger than 18 years in Ontario, Canada, with billing codes for VCUG and ICD-9 codes for VUR, from 2004-2014. The baseline characteristics included patient age, gender, geographic region, specialty of ordering provider and previous diagnoses of UTI and/or antenatal hydronephrosis to determine the indication for ordering the test. Of these, patients were subsequently incurred OHIP procedure codes for endoscopic injection or ureteral reimplantation. Patients who had a VCUG in the setting of urethral trauma, posterior urethral valves, and neurogenic bladder were excluded.

RESULTS AND DISCUSSION

Trend analysis demonstrated that the total number of VCUGs ordered in the province has decreased over a decade (Figure 1), with a concurrent decrease in VUR diagnosis. On multivariate regression analysis, the decrease in VCUG ordering could not be explained by changes in population demographics or other baseline patient variables. Most VCUGs obtained per year were ordered by pediatricians or family physicians (mean 2,022+523.8), compared with urologists and nephrologists (mean 616+358.3). Interestingly, while the rate of VCUG requests decreased, the annual number of surgeries performed for VUR (endoscopic or open) did not show a significant reduction over time.

CONCLUSIONS

We present a large population-based analysis in a universal access to care system, reporting a decreasing trend in the number of cystograms and differences by primary care versus specialist providers. While it is reassuring to see practice patterns favorably impacted by guidelines, it is also encouraging to note that the number of surgeries has remained stable. This suggests that patients at risk continue to be detected and offered surgical correction. These data confirm previous institution-based assessments and affirm changes in VCUG ordering independent of variables not relevant to the healthcare system, such as the insurance status.

The evaluation of vesicoureteral reflux among children using contrast-enhanced ultrasound: a literature review

INTRODUCTION

Voiding cystourethrogram (VCUG) with fluoroscopy remains the gold standard for detection and evaluation of vesicoureteral reflux (VUR) among children. However, the ionizing radiation exposure remains a concern for this diagnostic modality. Recent studies have proposed using contrast-enhanced ultrasound as an alternative option for VUR screening and follow-up in children. The aim of the study was to review the literature of comparative studies that assessed the diagnostic accuracy of contrast-enhanced ultrasound compared with VCUG.

METHODOLOGY

A systematic literature search was performed on electronic medical literature databases in July 2017. Literature identification, screening, and assessment of eligibility were performed by five reviewers with a pediatric radiologist. Literature was summarized for the study population, contrast used, and ultrasound mode as well as the timing of comparative reference study being performed. The studies were clustered according to the kind of contrast used. Reported diagnostic accuracy was extracted from individual studies and summarized across the included studies using descriptive statistics of median and interquartile range (IQR).

RESULT

A total of 45 comparative studies were identified as eligible for the summary of the literature. Two generations of ultrasound contrast were identified in the available studies (first generation, Levovist and second generation, SonoVue). For the ultrasound studies using the first-generation contrast, the median sensitivity, regardless of the ultrasound mode, was 90.25 (IQR 83.25-97), and the median specificity was 93 (IQR 91.3-95.25). Among studies using the second-generation contrast, the median sensitivity was 86.26 (IQR 81.13-97), and the median specificity was 90.99 (IQR 84-98). No serious adverse events were reported in any of the studies.

CONCLUSION

Overall, this review highlights the application of contrast-enhanced ultrasound for its advantage of no exposure to ionizing radiation and diagnostic accuracy relatively comparable to VCUG in the evaluation of VUR. In addition to the functional evaluation of the VUR, it also provides an anatomic evaluation of the kidneys and bladder with ultrasound imaging. However, one should also note that this alternate procedure is highly operator dependent where diagnostic accuracy is excellent when the expertise is available.

Diagnostic accuracy of contrast-enhanced voiding urosonogram using second-generation contrast with harmonic imaging (CEVUS-HI) study for assessment of vesicoureteral reflux in children: a meta-analysis

PURPOSE

To assess the diagnostic accuracy and safety of contrast-enhanced voiding urosonogram using second-generation contrast with harmonic imaging (CEVUS-HI) in detecting vesicoureteral reflux (VUR) among children.

METHODS

A systematic literature search was performed in March 2018. Relevant comparative studies from Medline, EMBASE, World of Science, Scopus, CENTRAL, WHO trial registry and Clinicaltrials.gov were identified and appraised using QUADAS-2. Diagnostic accuracy parameters were determined using VCUG as the reference standard. Adverse effects related to ultrasound contrast were summarized. The heterogeneity and inter-study variability were determined. After appropriate subgroup diagnostic accuracy parameters were investigated, summarizing receiver operator characteristics was constructed using the bivariate model meta-regression to determine the area under the curve (AUC).

RESULTS

A total of 12 studies with low-high risk of bias, including 1917 ureteral units from 953 patients were assessed for this meta-analysis. The included studies reported no serious adverse events associated with the ultrasound contrast. The pooled diagnostic accuracy parameters of CEVUS-HI in detecting VUR amongst children were: sensitivity 90.43 (95% CI 90.36-90.50), specificity 92.82 (95% CI 92.76-92.87), the calculated (+) likelihood-ratio 12.59 (95% CI 12.49-12.68), (-) likelihood-ratio of 0.103 (95% CI 0.102-0.104) and extrapolated pooled diagnostic odds-ratio was 122.12 (95% CI 120.75-123.49). Heterogeneity with interstudy variability was noted (p < 0.0001, I-squared > 70%). The AUC was determined to be 0.965 for VUR detection.

CONCLUSIONS

The pooled diagnostic accuracy parameters from low-moderate quality of evidence have illustrated that the CEVUS-HI study has an excellent safety profile and acceptable diagnostic accuracy. It may be considered as an alternative diagnostic modality for assessment of VUR among children.

Fibroepithelial polyp causing urethral obstruction: Diagnosis by cystourethrogram

Fibroepithelial polyps of the urethra are rare benign tumors that predominantly affect males in childhood or adolescence. In this report, we present a case of a 3-year-old boy in acute urinary retention with a urethral fibroepithelial polyp manifesting as a large filling defect on voiding cystourethrogram and successfully managed endoscopically with transurethral resection.

Variation in the level of detail in pediatric voiding cystourethrogram reports

INTRODUCTION

Voiding cystourethrogram (VCUG) provides a wealth of data on urinary tract function and anatomy, but few standards exist for reporting VCUG findings.

OBJECTIVE

We aimed to assess variability in VCUG reports and to test our hypothesis that VCUG reports from pediatric facilities and pediatric radiologists are more complete than those performed at other facilities or by non-pediatric radiologists.

STUDY DESIGN

We analyzed original VCUG reports from children enrolled in the Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) trial. A 23-item checklist was created and used to evaluate reporting of technical (e.g. catheter size), anatomic (e.g. vesicoureteral reflux (VUR) presence and grade, bladder shape), and functional information (e.g. bladder emptying). Radiologists were classified as pediatric or non-pediatric radiologists. Facilities were categorized as to whether they were a free-standing pediatric hospital (FSPH), a pediatric "hospital within a hospital" (PHWH), a non-pediatric hospital (NPH), or an outpatient radiology facility (ORF). Multivariate linear regression was used to analyze factors associated with the completeness of the VCUG reports (percent of items reported from the 23-item checklist).

RESULTS

Six-hundred and two VCUGs were performed at 90 institutions. Of those, 76% were read by a pediatric radiologist, and 49% were performed at a FSPH (Table). On average, less than half of the 23 items in our standardized assessment tool were included in VCUG reports (mean 48%, SD 12). The completeness of reports varied by facility type: 51% complete at FSPH (SD 11), 50% at PHWH (SD 10), 36% at NPH (SD 11), and 43% at ORF (SD 8) (p < 0.0001). In multivariate analysis, VCUG reports generated at NPH or ORF had 8% fewer items included (95% CI 3.0-12.8, p < 0.01), and those generated at PHWH did not differ from those generated at FSPH. Reports read by a non-pediatric radiologist had 6% fewer items included (95% CI 3-9.7; p < 0.01) compared with those read by a pediatric radiologist.

DISCUSSION

There is substantial underreporting of findings in VCUG reports when assessing a widely represented sample of routine, community-generated reports using an idealized standard. Although VUR was often reported, other crucial anatomic and functional findings of the VCUG were consistently underreported across all facility types.

CONCLUSION

Although pediatric radiologist and pediatric hospitals generated more complete VCUG reports compared with those having non-pediatric origins, the differences are small when considering the substantial underreporting of VCUG findings in general. This underscores the opportunities for improvement in reporting of VCUG findings.

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

INTRODUCTION

Voiding cystourethrography (VCUG) is the modality of choice to diagnose vesicoureteral reflux (VUR). Although grading of VUR is essential for prognosis and clinical decision-making, the inter-observer reliability for grading has been shown to vary substantially. The Randomized Intervention for Children with VesicoUreteral Reflux (RIVUR) trial provides a large cohort of children with VUR to better understand the reliability of VCUG findings.

OBJECTIVE

To determine the inter-observer consistency of the grade of VUR and other VCUG findings in a large cohort of children with VUR.

STUDY DESIGN

The RIVUR trial is a randomized controlled trial of antimicrobial prophylaxis in children with VUR diagnosed after UTI. Each enrollment VCUG was read by a local clinical (i.e. non-reference) radiologist, and independently by two blinded RIVUR reference radiologists. Reference radiologists' disagreements were adjudicated for trial purposes. The grade of VUR and other VCUG findings were extracted from the local clinical radiologist's report. The unit of analysis included individual ureters and individual participants. We compared the three interpretations for grading of VUR and other VCUG findings to determine the inter-observer reliability.

RESULTS

Six-hundred and two non-reference radiology reports from 90 institutions were reviewed and yielded the grade of VUR for 560 left and 524 right ureters. All three radiologists agreed on VUR grade in only 59% of ureters; two of three agreed on 39% of ureters; and all three disagreed on 2% of ureters (Table). Agreement was better (≥92%) for other VCUG findings (e.g. bladder shape "normal"). The non-reference radiologists' grade of VUR differed from the reference radiologists' adjudicated grade by exactly one grade level in 19% of ureters, and by two or more grade levels in 2.2% of ureters. When the participant was the unit of analysis, all three radiologists agreed on the grade of VUR in both ureters in just 43% of cases.

DISCUSSION

Our study shows considerable and clinically relevant variability in grading VUR by VCUG. This variability was consistent when comparing non-reference to the adjudicated reference radiologists' assessment and the reference radiologists to each other. This study was limited to children with a history of UTI and grade I-IV VUR and may not be generalizable to all children who have a VCUG.

CONCLUSION

The considerable inter-observer variability in VUR grading has both research and clinical implications, as study design, risk stratification, and clinical decision-making rely heavily on grades of VUR.

Posterior urethra: Anterior urethra ratio in the evaluation of success following PUV ablation

INTRODUCTION

There are conflicting reports on the criteria with which to determine success following posterior urethral valve (PUV) ablation. The aims of this study were to assess the value of the posterior urethra: anterior urethra ratio (PAR) in predicting successful PUV ablation.

MATERIALS AND METHODS

All neonates and infants with confirmed PUV on voiding cystourethrogram (VCUG) were included. Initial PAR was computed by dividing maximum posterior urethral diameter by anterior urethral diameter. Distances were measured by an on-screen distance measurement tool in the Radiology department, to avoid error. Only oblique images with good voiding phases were used for assessment. All patients underwent cystoscopy and PUV ablation using cold knife. Postoperative VCUG and cystoscopy were performed at 3 months follow-up. Success was defined as cystoscopic resolution of obstruction, in addition to biochemical and radiological improvement, and this was compared with PAR findings. An equal number of age-matched control patients who had a normal VCUG (as a part of evaluation of antenatal hydronephrosis) were also analyzed.

RESULTS

A total of 56 patients (median age 15 days, range 3-250 days) were analyzed between 2013 and 2016. The mean PAR was 1.5 (0.42) in controls and 3.42 (0.75) in those with PUV at diagnosis (P = 0.001). In those with successful PUV ablation (n = 51) the mean PAR was 1.8 (0.21), and in those with residual PUV/stricture (n = 5) the mean PAR was 3.16 (0.54). The difference between these two groups was statistically significant (P = 0.0001). Applying the value of mean + 2 SD of successful PUV ablation, an upper limit of PAR >2.2 was proposed to predict failure. Using this cut-off, 4/7 with PAR >2.2 had confirmed failure, while 48/49 with PAR <2.2 had successful resolution (P = 0.001) CONCLUSION: Whenever the posterior urethra is more than 2.2 times the diameter of the anterior urethra (PAR >2.2) on repeat VCUG following a PUV ablation, a cystoscopy check is essential to rule out residual PUV/stricture.

Utility of sedation for young children undergoing dimercaptosuccinic acid renal scans

BACKGROUND

No studies have examined whether use of sedation during a Tc-99 m dimercaptosuccinic acid (DMSA) renal scan reduces patient discomfort.

OBJECTIVE

To compare discomfort level during a DMSA scan to the discomfort level during other frequently performed uroradiologic tests, and to determine whether use of sedation during a DMSA scan modifies the level of discomfort.

MATERIALS AND METHODS

We examined the discomfort level in 798 children enrolled in the Randomized Intervention for children with Vesicoureteral Reflux (RIVUR) and Careful Urinary Tract Infection Evaluation (CUTIE) studies by asking parents to rate their child's discomfort level with each procedure on a scale from 0 to 10. We compared discomfort during the DMSA scan and the DMSA image quality between centers in which sedation was used >90% of the time (sedation centers), centers in which sedation was used <10% of the time (non-sedation centers), and centers in which sedation was used on a case-by-case basis (selective centers).

RESULTS

Mean discomfort level was highest for voiding cystourethrogram (6.4), followed by DMSA (4.0), followed by ultrasound (2.4; P<0.0001). Mean discomfort level during the DMSA scan was significantly higher at non-sedation centers than at selective centers (P<0.001). No difference was apparent in discomfort level during the DMSA scan between sedation centers and selective centers (P=0.12), or between the sedation centers and non-sedation centers (P=0.80). There were no differences in the proportion with uninterpretable DMSA scans according to sedation use.

CONCLUSION

Selective use of sedation in children 12-36 months of age can reduce the discomfort level experienced during a DMSA scan.

Delayed upper tract drainage on voiding cystourethrogram may not be associated with increased risk of urinary tract infection in children with vesicoureteral reflux

INTRODUCTION

Urinary stasis in the setting of obstruction provides an opportunistic environment for bacterial multiplication and is a well-established risk factor for UTI. Vesicoureteral reflux (VUR) with delayed upper tract drainage (UTD) on VCUG has been reported to correlate with increased UTI risk. We sought to determine whether delayed UTD can be reliably classified, and whether it correlates with UTI incidence, VCUG, or endoscopic findings.

METHODS

Children undergoing endoscopic surgery for primary VUR (2009-2012) were identified. VUR grade, timing, and laterality were abstracted. Demographics, hydrodistention (HD) grade, reported febrile and culture-proven UTI were assessed. UTD on VCUG was graded on post-void images as 1 = partial/complete UTD or 2 = no/increased UTD. Inter-observer agreement was calculated. Patients were excluded for incomplete imaging or inability to void during VCUG.

RESULTS

The cohort included 128 patients (10M, 118F), mean age 4.1 ± 2.1 years. Mean age at diagnosis was 2.8 ± 2.8 years. Mean maximum VUR grade was 3 ± 0.9: 1 (7.8%), 2 (20.3%), 3 (43%), 4 (25.8%), 5 (3.1%). UTD occurred in 45 (35%), and no drainage in 83 (65%) patients. Agreement coefficient between graders was 0.596 (p < 0.0001). Cultures were available in 100 patients (70 positive). Patients experienced a mean of 2 ± 1.2 parent-reported fUTIs and 1.2 ± 1.2 culture-proven UTIs from birth to surgery. UTI rate did not differ by UTD status for parent or culture-proven UTI (Table). On multivariate analysis, no patient characteristic was a significant predictor of UTI based on drainage status. Children diagnosed with VUR before 1 year of age had a higher verified UTI rate (p < 0.001). However, drainage was not a significant predictor of UTI rate and when testing the interaction of drainage and age.

CONCLUSION

We sought to determine whether UTD was an accurate predictor of UTI risk to maximize available prognostic information from a single VCUG. Delayed UTD was not a predictor of infection in our patients, nor was it associated with previously described UTI risk factors, such as VUR timing or grade, and voiding dysfunction. Limitations included the retrospective nature of the study in patients undergoing endoscopic VUR treatment, and possible inaccurate UTI reports from parents and pediatricians. UTD can be reliably scored using a binary system with high inter-observer correlation. Our data call into question the previous finding that children with poor UTD are at increased risk of recurrent UTI. Delayed UTD is also not associated with higher HD, or VUR grade compared with those with more prompt UTD.

Comparing between results and complications of doing voiding cystourethrogram in the first week following urinary tract infection and in 2-6 weeks after urinary tract infection in children referring to a teaching hospital

Introduction: Urinary tract infection is the most common genitourinary disease in children so about 40% of the children with urinary tract infection suffering from reflux that caused some consequences such as pyelonephritis and kidney parenchymal injury.

Objectives: This research was conducted to compare the timing of voiding cystourethrogram (VCUG) in children with urinary tract infection in first week and after the first week of urinary tract infection.

Patients and Methods: This research is a case-control study that both case and control groups include 208 children from 1 month to 12 years old with the complain of urinary tract infection. In case group, the VCUG was performed at the first week of infection and in control group, the VCUG was performed after the first week of infection.

Results: complication such as dysuria was observed in two-thirds of children who VCUG was performed during first week after urinary tract infection. Parents stress in case group was more than the other (P=0.015). For overall, the incidence of reflux in case and control groups was 49.5% and 50%, respectively. The mean of reflux grading in right kidney in case group was lower than control group resulting in significant differences between two groups.

Conclusion: According to higher grade of stress in parents and complications due to VCUG at the first week of urinary tract infection, it is suggested that VCUG be conducted on selective patients in the hospital at the first week of urinary tract infection and during hospitalization.

Radiation exposure contribution of the scout abdomen radiograph in common pediatric fluoroscopic procedures

BACKGROUND

Contrast enema, voiding cystourethrography and upper gastrointestinal studies are the most common fluoroscopic procedures in children. Scout abdomen radiographs have been routinely obtained prior to fluoroscopy and add to the radiation exposure from these procedures. Elimination of unnecessary routine scout radiographs in select studies might significantly reduce radiation exposure to children and improve the overall benefit-to-risk ratio of these fluoroscopic procedures.

OBJECTIVE

To determine the radiation exposure contribution of the preliminary/scout abdomen radiographs with respect to the radiation exposure of the total procedure.

MATERIALS AND METHODS

We retrospectively collected demographic information and radiation exposure values of dose area product (in Gy-cm(2)) and entrance air kerma (in mGy) - initially for the scout abdomen radiographs done prior to fluoroscopy and subsequently the total procedural radiation values (the combined values of the scout radiograph and fluoroscopic radiation exposure) - in children who underwent contrast enemas, voiding cystourethrograms and upper gastrointestinal studies in a 4-month period. The radiation parameters, including fluoroscopy time, dose area product and entrance air kerma, were available in the log book maintained in the fluoroscopy suite. Fluoroscopy procedures were performed on a single fluoroscopy machine using four frames per second pulse rate and other radiation-minimizing techniques. Usage of the grid to obtain scout radiographs was also recorded. The proportion of radiation exposure from the scout radiograph relative to that of the total procedure was calculated by dividing the individual parameters of the scout to the total procedural values and multiplied by 100 to express these values as a percentage. We calculated mean, median and range and performed statistical analysis of the data.

RESULTS

A total of 151 procedures performed on 71 males and 80 females qualified for the study. The age range of the patients was 2 days to 18 years, with a mean of nearly 3.5 years (40 months) and median of 15 months. There were 63 upper gastrointestinal studies, 65 voiding cystourethrography studies and 23 contrast enema studies. The fluoroscopy time for all procedures combined ranged from 0.1 min (6 s) to 2 min, with mean and median values of 0.4 min and 0.3 min, respectively. The fractional radiation exposure contribution for the dose area product of scout abdomen radiograph to the total procedure ranged from 4% to 98%, with mean and median values of 51% and 49%, respectively. The fractional contribution of the scout radiograph to the total procedure for the entrance air kerma values ranged from 6% to 97%, with mean and median values of 29% and 26%, respectively. There was a significant negative correlation (P<0.001) between fluoroscopy radiation time and the proportion of radiation parameters of scout radiograph to total procedural values.

CONCLUSION

Scout radiographs can contribute a significant proportion (median values of approximately 50% for the dose area product and 26% for the entrance air kerma) of radiation exposure in common fluoroscopy procedures in children.

Distress experienced during pediatric VCUGs - a granular, prospective assessment using the brief behavioral distress scale

BACKGROUND

In spite of decades of experience with the procedure, controversy persists as to the overall distress experienced by children and the routine need for sedation in children undergoing voiding cystourethrograms (VCUG). Many studies have attempted to address these issues, often divided into one camp that champions routine sedation while another group believes that pretest preparation is often all that is needed. At the root of these issues are some of the limitations of previous studies as most incorporate inherently subjective parental questionnaires to determine distress levels rather than using an objective, unbiased observer.

OBJECTIVE

The objective of this study is to use a validated and reliable tool (the brief behavioral distress scale) to objectively evaluate the distress experienced during VCUGs.

MATERIALS AND METHODS

A prospective study of 26 children (ages 3-7 years old) was performed by the pediatric radiology department at a large urban academic medical center. Patients were evaluated for distress during 12 separate VCUG steps beginning with the patient entering the room and ending with the clothing being replaced at study completion.

RESULTS

Using a general linear model (repeated measures analysis of variance (ANOVA)), significant distress was identified during two phases of the examination, catheter insertion (P-values ranging <0.001-0.19) and the full bladder phase (P-values ranging 0.005-0.043). The mean distress score for catheter insertion (mean: 1.38, standard deviation [SD]: 1.098) was nearly three times higher than the next most distressful step, i.e. full bladder (mean: 0.65, SD: 0.745). Additionally, entering the room was perceived as significantly more distressing than the catheter out (P = 0.016) and clothing replacement phase (P = 0.006).

CONCLUSION

We find that despite there being significantly increased distress during the catheter insertion and full bladder phases, the distress levels during VCUGs are markedly less than in previous reports. Even the most distressful stage, catheterization, was less stressful than previously reported with levels closer to that of minor distress evinced by comfort-seeking behavior from a parent rather than more significant distress resulting in screaming. Our findings corroborate and expand on the conclusion of the effectiveness of pretest preparation and child life specialist involvement.

The "flowerpot" sign: inference of poor renal function in high grade vesicoureteral reflux by calyceal orientation

INTRODUCTION/OBJECTIVE

Modern radiographic advances have allowed for detailed and accurate imaging of not only urologic anatomy but also urologic function. The art of observational inference of subtle anatomic features and function from a static radiograph is being traded for new, more precise, and more expensive modalities. While the superiority of these methods cannot be denied, the total information provided in simpler tests should not be ignored. The relationship between high grade vesicoureteral reflux with the dilated calyces arranged cephalad to a dilated funnel-shaped renal pelvis on VCUG and reduced differential renal function has not been previously described, but has been anecdotally designated a "flowerpot" sign by our clinicians. We hypothesize that the appearance of a "flowerpot" kidney as described herein is an indicator of poor renal function in the setting of high grade VUR.

STUDY DESIGN

IRB approval was obtained and 315 patients were identified from system-wide VCUG reports from 2004-2012 with diagnosed "high grade" or "severe" vesicoureteral reflux. Inclusion into the study required grade IV or V VUR on initial VCUG and an initial radionuclide study for determination of differential function. Patients with a solitary kidney, posterior urethral valve, multicystic dysplastic kidney, renal ectopia, or duplex collecting systems were excluded. Grade of reflux, angle of the inferior-superior calyceal axis relative to the lumbar spine, and differential uptake were recorded along with presence of the new "flowerpot" sign. Variables were analyzed using the Mann-Whitney U test to determine statistical significance.

RESULTS

Fifty seven patients met inclusion criteria with 11 being designated as "flowerpot" kidneys. These "flowerpot" kidneys could be objectively differentiated from other kidneys with grade IV and/or grade V VUR both by inferior-superior calyceal axis (median angle, 52° [37-66] vs. 13° [2-37], respectively p < 0.001) and by differential renal uptake (median, 23% [5-49] vs. 45% [15-81], respectively p < 0.001). Likewise, there was no difference between either calyceal axis (median angle, 13° [3-20] vs. 13° [2-37]) or differential function (median, 48% [24-81] vs. 40% [15-66], p = 0.129) when comparing kidneys with grade IV and grade V VUR, respectively, that did not demonstrate the "flowerpot" sign.

DISCUSSION/CONCLUSION

Grading of VUR is used to provide a common language for scientific discussion and determine prognosis for children with similar attributes. The dysmorphic calyceal system in the "flowerpot" kidneys supports the theory of abnormal renal blastema induction associated with abnormal differentiation of the ureteral bud. Even in the absence of urinary tract infections and/or pyelonephritis, renal abnormalities and decreased differential function can be observed on renal scintigraphy. This study also confirms the male predominance and functional similarities between grade 4 and 5 refluxing renal units. Recognizing this is a limited observational study based on imaging alone, the "flowerpot" sign is an indicator of the most severe form of grade 5 VUR but is only one factor in predicting long term overall renal prognosis. However, 14% (8/57) of our cohort had a relative uptake of less than 20% with 5 of these exhibiting the "flowerpot" sign. The "flowerpot" sign on VCUG can be used as indirect evidence of poor differential renal function and, therefore, useful in guiding parental expectations prior to formal functional imaging.

Vesicoureteral reflux and febrile urinary tract infections in anorectal malformations: a retrospective review

BACKGROUND

Multiple studies document a correlation between anorectal malformations (ARMs) and vesicoureteral reflux (VUR), development of urinary tract infections (UTIs), and subsequent renal disease. We aimed to determine which patient characteristics are associated with VUR and UTI in this population.

METHODS

A retrospective review of ARM patients at a free-standing children's hospital from January 1996 to December 2011 was performed. Logistic regression was used to investigate the associations between VUR and UTI and ARM classification and co-morbid diagnoses.

RESULTS

Of 190 patients, 41 (31%) received a diagnosis of VUR. Thirty-one of the 190 patients had at least one febrile UTI (16%). Of these, only 16 (51%) had a diagnosis of VUR. On multivariable logistic regression, the only patient variable associated with VUR was having an ectopic kidney (p=0.026). Similarly, the presence of GU malformations was the closest variable associated with developing a UTI (p=0.073).

CONCLUSIONS

In ARM patients, VUR as well as UTIs are associated with the presence of GU malformations. Thus, voiding cystourethrogram (VCUG) testing should be pursued when there are other caudal and GU abnormalities, regardless of fistula location. Antibiotic prophylaxis for UTI should be considered in children with ARM and any GU malformation, not only VUR.

Positioning irrigation of contrast cystography for diagnosis of occult vesicoureteric reflux: association with technetium-99m dimercaptosuccinic acid scans

OBJECTIVE

Positioning irrigation of contrast (PIC) cystography identifies occult or PIC vesicoureteral reflux (PIC-VUR) in children with recurrent febrile urinary tract infections (UTI) but no vesicoureteric reflux (VUR) on standard voiding cystourethrogram (VCUG). We sought to identify the relationship between PIC-VUR and renal scarring in technetium-99m dimercaptosuccinic acid (DMSA) scans.

PATIENTS AND METHODS

We retrospectively analysed PIC cystograms and DMSA scans for 154 kidneys in 81 children (65 girls; 16 boys; median age, 4.7 years; range, 0.9-15.2). Renal scarring was graded on a scale of 0-3. DMSA scans were pathologic in 66 patients (81%). Children had experienced mean 3.8 febrile UTI (range 1-25). Forty-seven (58%) children had a history of reflux, including 15 (19%) with previous anti-reflux operations. Indications for PIC cystography were recurrence of febrile UTI after either bilateral negative VCUG (66 children) or unilateral VUR (15 children) with contralateral/bilateral scarring or reflux that had changed sides in subsequent VCUGs.

RESULTS

PIC-VUR was bilateral in 63, unilateral in 12, and absent in 6 children. Statistically significant associations between PIC-VUR grade and severity of renal scarring were identified in inter-individual (n = 77, p = 0.017) and intra-individual (refluxing vs. nonrefluxing kidney; n = 12, p = 0.008) analyses. After excluding patients with history of VUR, statistical significance was maintained in inter-individual analysis (n = 49; p = 0.018).

CONCLUSION

The data suggest an association between PIC-VUR and severity of renal scarring, and legitimise the use of PIC cystography in children with renal scarring due to recurrent febrile UTI but negative findings on VCUG.