[Voiding cystourethrography : Indications, fluoroscopy technique and radiation protection]. / Miktionszysturethrographie : Indikationen, Durchleuchtungstechnik und Strahlenschutz.

BACKGROUND: Voiding cystourethrography continues to be the gold standard in the diagnostics of a wide range of diseases of the urinary tract in children. MATERIAL AND METHODS: Indications, implementation of voiding cystourethrography in terms of preparation, materials used, dealing with the child and the parents as well as the standardized examination technique are presented. In particular, the technical aspects of fluoroscopy devices and criteria for good image quality are discussed. Case studies are used to illustrate the problems of frequent urological diseases. DISCUSSION: The three standard examinations for the detection of vesicoureteral reflux (VUR), radionuclide cystography, contrast-enhanced voiding urosonography and voiding cystourethrography are compared. Their potential for detecting VUR and additional urological pathologies is discussed in detail. Furthermore, the optimized examination technique of voiding cystourethrography is presented. The applicability of the current dose reference values of the German Federal Office for Radiation Protection (BfS) in the daily routine is discussed and the feasibility of the dose reference values is explained.

The accuracy of cystography under general anesthesia in children with vesicoureteral reflux.

PURPOSE: To examine the accuracy of cystography under general anesthesia in children with vesicoureteral reflux (VUR). MATERIALS AND METHODS: A prospective study of children who had VUR on cystography without general anesthesia (i.e., the gold-standard), and who are candidates for endoscopic VUR repair surgery. All children subsequently underwent a cystography under general anesthesia before injection using standardized method, which was compared to the gold-standard cystography. χ2 and Mann-Whitney U tests were used to compare proportions and medians between groups. RESULTS: Between 2017 and 2021, 126 renal units in 13 boys and 50 girls were included. Median age was 3.4 years (interquartile range [IQR] 1.5-6.5). Median time from cystography without to cystography with general anesthesia was 3.8 months (IQR 2.7-6). Of the 126 renal units, 96 had VUR on cystography without general anesthesia. On dichotomous analysis (no VUR vs. any VUR) sensitivity, specificity, negative and positive predictive values of cystography under general anesthesia were 47% (45/96), 87% (26/30), 34% (26/77) and 92% (45/49), respectively. Accuracy was 56.3%; Cohen's Kappa coefficient was 0.22, indicating poor agreement. In subgroup analysis, the sensitivity of cystography under general anesthesia was significantly lower in primary VUR (20% vs. 55% in secondary VUR, p = 0.01) and active VUR (14% vs. 52% in passive VUR, p = 0.008). CONCLUSION: Cystography under general anesthesia was poorly correlated to cystography performed while the child was awake or lightly sedated. Clinical decision relying on this cystography is questionable.

Contrast-enhanced voiding urosonography (CEVUS) as a safe alternate means of assessing vesicoureteral reflux in pediatric kidney transplant patients.

BACKGROUND: Although voiding cystourethrogram (VCUG) is currently the gold standard in VUR evaluation, there is ionizing radiation exposure. Contrast-enhanced voiding urosonography (CEVUS) uses ultrasound contrast agents to visualize the urinary tract and has been reported to be safe and effective in VUR evaluation in children. CEVUS application has yet to be specifically described in VUR evaluation in the pediatric kidney transplant population. The purpose of this study was to report the use of CEVUS and VCUG in evaluating and managing VUR in pediatric renal transplant patients. METHODS: Retrospective review was conducted for pediatric kidney transplant patients (18 years and younger) who underwent VCUG or CEVUS to assess for transplant VUR from July 2019 through June 2021. Demographic information, reason for VUR evaluation, fluoroscopy time, and postimaging complications were evaluated. Costs of imaging modalities were also considered. RESULTS: Eight patients were evaluated for transplant VUR during the study period. Of the 3 patients who underwent VCUG, all 3 had VUR (median grade 3). Median fluoroscopy time was 18 s and dose-area product was 18.7 uGy*m2 . Of the 5 patients who underwent CEVUS, 4 had VUR (median grade 4). There were no complications for either modality. Based on clinical and radiographic findings, patients were recommended no intervention, behavioral modification, or ureteral reimplantation. The total cost of CEVUS was $800 less than that of VCUG. CONCLUSION: CEVUS can provide an alternate means of safely evaluating VUR in kidney transplant patients with similar outcomes, potentially lower costs, and no exposure to ionizing radiation.

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

BACKGROUND: There is limited quality of evidence regarding the accuracy of contrast-enhanced voiding urosonography (ceVUS) for diagnosis of vesicoureteral reflux (VUR) compared to fluoroscopic voiding cystourethrography (VCUG), and minimal data on the use of the ultrasound contrast agent Optison™ for this purpose. OBJECTIVE: To compare the accuracy of ceVUS using Optison™ to VCUG, and to assess inter-rater agreement regarding presence and grading of VUR. STUDY DESIGN: In this retrospective investigation, all sequential ceVUS with Optison™ and VCUG studies performed in children between 2014 and 2017 were reviewed. Two raters independently graded all ceVUS studies using a 5-point scale. CeVUS sensitivity and specificity were estimated separately for each rater using the VCUG report as the ground truth for presence and degree of VUR. Logistic and ordinary linear regression models assessed rater-report agreement and inter-rater agreement for each kidney, Optison™ dose, and referral diagnosis. RESULTS: 97 children (51 females) with 101 paired studies were included. Sensitivity and specificity of ceVUS for VUR detection were identical for both raters: right kidney 75%/90.9%; left kidney 85.7%/78.9% (Figure). There was no statistically significant difference in disagreement between raters and the VCUG report for the right or left kidney. Inter-rater agreement on ceVUS grading was 90% and 88% for right and left kidneys, respectively. There was a significant negative association between fetal hydronephrosis vs urinary tract infection and disagreement between Rater 2 and the VCUG report for the left kidney. There were no other significant associations with respect to either kidney, Optison™ dose, or referral diagnosis. DISCUSSION: Our study showed that detection of VUR with ceVUS and Optison™ is comparable to fluoroscopic VCUG. Based on the VCUG reports, the incidence of VUR in our patient population was substantially lower than in the meta-analysis of Chua et al. and in the study of Kim et al. The explanation for the large discrepancy in VUR incidence may reflect differences in the patient populations, and in our reporting of VUR with respect to kidney number rather than to pelviureteral units. Study limitations include its retrospective nature and potential bias in terms of patient selection. Since VUR is an intermittent phenomenon, sequential rather than simultaneous performance of the ceVUS and fluoroscopic studies might have influenced VUR detection. CONCLUSION: A blinded comparison of ceVUS performed with Optison™ to fluoroscopic VCUG showed moderate-good sensitivity and specificity for diagnosis of VUR.

Multi-institutional Validation of Improved Vesicoureteral Reflux Assessment With Simple and Machine Learning Approaches.

PURPOSE: Vesicoureteral reflux grading from voiding cystourethrograms is highly subjective with low reliability. We aimed to demonstrate improved reliability for vesicoureteral reflux grading with simple and machine learning approaches using ureteral tortuosity and dilatation on voiding cystourethrograms. MATERIALS AND METHODS: Voiding cystourethrograms were collected from our institution for training and 5 external data sets for validation. Each voiding cystourethrogram was graded by 5-7 raters to determine a consensus vesicoureteral reflux grade label and inter- and intra-rater reliability was assessed. Each voiding cystourethrogram was assessed for 4 features: ureteral tortuosity, proximal, distal, and maximum ureteral dilatation. The labels were then assigned to the combination of the 4 features. A machine learning-based model, qVUR, was trained to predict vesicoureteral reflux grade from these features and model performance was assessed by AUROC (area under the receiver-operator-characteristic). RESULTS: A total of 1,492 kidneys and ureters were collected from voiding cystourethrograms resulting in a total of 8,230 independent gradings. The internal inter-rater reliability for vesicoureteral reflux grading was 0.44 with a median percent agreement of 0.71 and low intra-rater reliability. Higher values for each feature were associated with higher vesicoureteral reflux grade. qVUR performed with an accuracy of 0.62 (AUROC=0.84) with stable performance across all external data sets. The model improved vesicoureteral reflux grade reliability by 3.6-fold compared to traditional grading (P < .001). CONCLUSIONS: In a large pediatric population from multiple institutions, we show that machine learning-based assessment for vesicoureteral reflux improves reliability compared to current grading methods. qVUR is generalizable and robust with similar accuracy to clinicians but the added prognostic value of quantitative measures warrants further study.

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.

Evaluating the accuracy of simplified VCUG in comparison with traditional VCUG for diagnosis of urinary-reflux in children: Radiation dose reduction.

INTRODUCTION: Voiding cystourethrogram (VCUG) is an imaging technique for diagnosing urinary-reflux. VCUG requires X-ray exposure, increasing the risk of malignancies induced by ionizing radiation, especially in children. Considering the importance of early diagnosis of urinary-reflux using VCUG to prevent kidney complications and the significance of reducing the radiation dose during this imaging, this study intends to reduce the imaging views of VCUG and evaluate the urinary-reflux, using a reduced number of images. MATERIAL AND METHODS: Children referred to a University hospital who underwent VCUG participated in this study. The routine VCUG procedure contained five images. Two images of full-bladder and post-void of each patient were considered a simplified procedure and were evaluated by two radiologists to determine reflux and its grade. The sensitivity and specificity of simplified VCUG were determined. RESULTS: 182 patients with a mean age of 5.36±4.95 years old participated in this study. There were 90% and 82% agreement between routine and simplified VCUG results in the left and right kidneys. The simplified VCUG had 87.2% and 100% sensitivity and specificity in detecting the left-side reflux, 83 .9% and 100%, to detect the right-side reflux. CONCLUSION: The results showed that using two images instead of five can effectively diagnose and grade urinary-reflux. The simplified VCUG had a relatively good and acceptable agreement in comparison to the routine cystourethrogram. It can effectively reduce the patient's radiation dose, especially in patients who need to perform serial bladder imaging for follow-up after operation.

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.

Feasibility of Dual-Energy Computed Tomography Imaging of Gadolinium-Based Contrast Agents and Its Application in Computed Tomography Cystography: An Exploratory Study to Assess an Alternative Option When Iodinated Contrast Agents Are Contraindicated.

OBJECTIVE: The aim of this study was to compare the contrast enhancement differences between gadolinium-based and iodine-based contrast agents at different single-energy tube potentials and dual-energy-based virtual monochromatic energies. In addition, we describe the application of a gadolinium-based contrast agent in computed tomography (CT) cystography for a patient with contraindications to iodine. METHODS: A phantom study was performed using 3 iodine samples (concentrations: 5, 10, and 15 mgI/mL) and 3 gadolinium samples (concentrations: 3.3, 6.6, and 9.9 mgGd/mL). The prepared phantom was scanned by a dual-energy CT (DECT) at 80, 100, 120, and 140 kV in the single-energy mode and at 100/Sn140 kV in the dual-energy mode. Virtual monoenergetic images (VMIs) at 50 keV were generated from the DECT scan. In addition, a DECT cystogram was performed using a gadolinium-based contrast agent in a patient with contraindications to iodinated contrast. RESULTS: Strong linear correlations between mean signal of contrast enhancement and mass concentration were found for both iodine and gadolinium samples across all single-energy CT (SECT) and DECT scan conditions. The VMI at 50 keV provided the highest contrast enhancement for both types of contrast samples at each concentration level, and single-energy CT scans at low-energy beams showed higher contrast enhancement than higher beam energies. In addition, the contrast enhancement for pure gadolinium solution was constantly higher than pure iodine solution at an identical mass concentration level. The DECT cystogram was performed with excellent technical success. The urinary bladder was appropriately distended with intravesical contrast measuring 606 Hounsfield units and no evidence of bladder leak or fistula. CONCLUSIONS: Imaging of gadolinium-based contrast agents is improved using a DECT technique, with VMI at 50 keV providing the highest contrast enhancement among our tested parameters. Dual-energy CT cystography using a gadolinium-based agent can be a safe and effective alternative when iodinated agents are contraindicated.

Top-Down versus Bottom-Up Approach in Children Presenting with Urinary Tract Infection: Comparative Effectiveness Analysis Using RIVUR and CUTIE Data.

PURPOSE: The initial imaging approach to children with urinary tract infection (UTI) is controversial. Along with renal/bladder ultrasound, some advocate voiding cystourethrogram (VCUG), ie a bottom-up approach, while others advocate dimercaptosuccinic acid (DMSA) scan, ie a top-down approach. Comparison of these approaches is challenging. In the RIVUR/CUTIE trials, however, all subjects underwent both VCUG and DMSA scan. Our objective was to perform a comparative effectiveness analysis of the bottom-up vs top-down approach. MATERIALS AND METHODS: We simulated 1,000 hypothetical sets of 500 children using RIVUR/CUTIE data. In the top-down approach, patients underwent initial DMSA scan, and only those with renal scarring underwent VCUG. In the bottom-up approach, the initial study was VCUG. We assumed all children with vesicoureteral reflux (VUR) received continuous antibiotic prophylaxis (CAP). Outcomes included recurrent UTI, number of VCUGs and CAP exposure. We assumed a 25% VUR prevalence in children with initial UTI with sensitivity analysis using 40% VUR prevalence. RESULTS: Median age of the original RIVUR/CUTIE cohort was 12 months. First DMSA scan was performed at a median of 8.2 weeks (IQR 5-11.8) after the index UTI. In the simulated cohort, slightly higher yet statistically significantly recurrent UTI was associated with the top-down compared with the bottom-up approach (24.4% vs 18.0%, p=0.045). On the other hand, the bottom-up approach resulted in more VCUG (100% vs 2.4%, p <0.001). Top-down resulted in fewer CAP-exposed patients (25% vs 0.4%, p <0.001) and lower overall CAP exposure (5 vs 162 days/person, p <0.001). Sensitivity analysis was performed with 40% VUR prevalence with similar results. CONCLUSIONS: The top-down approach was associated with slightly higher recurrent UTI. Compared to the bottom-up approach, it significantly reduced the need for VCUG and CAP.

Is there a need for endoscopic evaluation in symptomatic boys with an unsuspicious urethra on VCUG? A consideration of secondary radiologic signs of posterior urethral valves.

INTRODUCTION: A significant proportion of PUV becomes symptomatic after the perinatal period. Voiding cystourethrography (VCUG) often fails to identify PUVs. This study evaluates the relationship between the radiological appearance of the posterior urethra, potential secondary radiological signs and endoscopically documented PUV in boys with febrile UTIs, VUR, refractory symptoms of bladder overactivity or suggestive sonography findings. PATIENTS AND METHODS: Data on VCUG findings and endoscopy from 92 boys (mean age 27 months) who underwent endoscopic PUV incision between 2012 and 2017 following a VCUG were reviewed. 24 boys with endoscopically unsuspicious urethras were included as control group (mean age 27.5 months). Statistical analysis was performed using Fisher's exact test. RESULTS: In patients with PUV, the urethra was suspicious on a preoperative VCUG in 45.7%, whereas it appeared normal in 54.3%. Abortive forms of PUV were more frequently found in patients with a radiologically unsuspicious urethra (30%vs.16.7%, p = 0.15). Bladder neck hypertrophy on VCUG (16.7%vs.60.9%, OR 7.5, p < 0.001), a trabeculated bladder on VCUG (72%vs.37.5%, OR 4.3, p < 0.001) and a hypertrophied musculus interuretericus (38%vs.4.2%, OR 11.7, p < 0.001) were more common in patients with PUV and urethras appearing normal on VCUG as compared to controls. CONCLUSION: Unsuspicious findings of the urethra on VCUG cannot exclude a relevant PUV and implicate a risk of disregarding abortive forms. The presence of secondary radiologic signs of infravesical obstruction on a VCUG despite an unsuspicious posterior urethra in boys with recurrent UTI's as well as refractory symptoms of bladder overactivity or suggestive signs on sonography must be further clarified endoscopically.

Diagnostic accuracy of pneumo-CT-cystography in the detection of bladder rupture in patients with blunt pelvic trauma.

PURPOSE: To evaluate the diagnostic utility of bladder air distension (pneumo-CT-cystography) in the detection of bladder rupture in patients with blunt pelvic trauma. MATERIALS AND METHODS: 843 patients with blunt pelvic trauma were evaluated. Intravenous contrast-enhanced CT was performed for trauma staging. 97 of 843 patients had clinical and radiological signs of possible bladder injury and underwent retrograde air distension. RESULTS: Among 97 patients, 31/97 showed CT signs of bladder rupture, of which 5/31 (16%) intraperitoneal, 25/31 (81%) extraperitoneal and 1/31 (3%) combined. 23 of these patients underwent surgery, which confirmed bladder injury in 100% of cases. The other 8 patients were managed conservatively, and follow-up studies showed disappearance of free air. Among the 66/97 patients with no signs of bladder injury, 38/66 had surgery, which confirmed bladder integrity, while 28/66 were managed conservatively and showed no signs of bladder rupture at clinico-radiological follow-up examinations. CONCLUSIONS: CT evaluation of urinary bladder after retrograde air distension (pneumo-CT-cystography) may be a reliable diagnostic tool in the detection of bladder rupture in patients with blunt pelvic trauma. This technique is faster, cheaper and allows to overcome some of the limitations of conventional CT-cystography.

The Importance of Cystoscopy in Diagnosis and Treatment of Urethral Stricture Following Transurethral Prostatectomy.

BACKGROUND: Transurethral prostatectomy is the gold standard surgical treatment of bladder outlet obstruction due to benign enlargement of the prostate, with more than 30,000 procedures performed annually in the United States alone. The success rate of this minimally invasive procedure is high and the results are durable. The development of urethral stricture is a long-term complication of the procedure and is noted in about 2% of patients. The stricture narrows the urethral lumen, leading to re-appearance of obstructive urinary symptoms. Traditionally, the evaluation of the stricture was performed by retrograde urethrography. Advancements in the fields of flexible endoscopy allowed rapid inspection of the urethra and immediate dilatation of the stricture in selected cases. OBJECTIVES: To compare the efficacy of urethrography versus cystoscopy in the evaluation of urethral strictures following transurethral prostatectomy. METHODS: A retrospective review was conducted of a series of 32 consecutive patients treated due to post-transurethral resection of prostate (TURP) urethral stricture. RESULTS: Twenty patients underwent both tests. In 16 there was concordance between the two tests. Four patients had no pathological findings in urethrography but had strictures in cystoscopy. All strictures were short (up to 10 mm) and were easily treated during cystoscopy, with no complaints or re-surgery needed in 24 months follow-up. CONCLUSIONS: Cystoscopy was superior to urethrography in the evaluation of post-TURP strictures. Strictures where often short and treated during the same procedure. We recommend that cystoscopy be the procedure of choice in evaluating obstructive urinary symptoms after TURP, and retrograde urethrography be preserved for selected cases.

Reflujo vesicoureteral en pacientes diagnosticados de estenosis de la unión pieloureteral. ¿Está justificado el screening? / Vesicoureteral reflux in patients diagnosed with pyeloureteral junction obstruction. Is screening justified?

Introducción: La concomitancia entre la estenosis de la unión pieloureteral (EPU) y el reflujo vesicoureteral (RVU) se sitúa entre el 5,2 y el 18%. Actualmente, no existe consenso sobre la realización de screening rutinario para descartar dicho reflujo, pudiendo limitarlo a pacientes seleccionados. Objetivos: Estudiar la prevalencia del RVU en los pacientes diagnosticados de EPU. Estimar el grado de reflujo en aquellos pacientes con estudio positivo. Limitar la realización de cistouretrografía miccional seriada CUMS o de ecocistografía a pacientes seleccionados (uréter dilatado visible en ecografía, ITU previa). Material y métodos: Estudio observacional y retrospectivo sobre 74 pacientes intervenidos de EPU. Se ha recogido información acerca del sexo, realización de despistaje preoperatorio de RVU, los resultados (positivo o negativo para RVU) y grado de reflujo. Resultados: 53 casos fueron masculinos (71,6%) y 21 (28,4%) femeninos. El despistaje de reflujo fue realizado en 55 pacientes (74,3%) frente a 18 (24,3%) en los que no se realizó ningún estudio. El 16,2% de los casos en los que se realizó el estudio preoperatorio de RVU fueron abordados mediante ecocistografía, siendo el estudio preoperatorio positivo en 6 pacientes del total de 73 estudiados (un paciente fue excluido por ser diagnosticado de válvulas de uretra posterior), lo que sitúa la prevalencia de RVU en pacientes ya diagnosticados de EPU en un 10,7%. De estos, un caso fue de grado I, dos grado II y un caso grado III, IV y V, respectivamente. Conclusiones: El RVU en pacientes diagnosticados de estenosis de la unión pieloureteral presenta una incidencia ligeramente mayor que en la población general. El screening rutinario del reflujo vesicoureteral es innecesario, debiendo realizarse en casos que presenten infecciones urinarias previas, visualización del uréter dilatado en la ecografía o sospecha de causa secundaria

Introduction: The prevalence of vesicoureteral reflux (VUR) con-comitant with pyeloureteral junction obstruction (PUJO) ranges from 5.2% to 18%. Today, there is no consensus on whether routine screening should be performed or not to rule out reflux, and it can be limited to selected patients. Objectives: To study VUR prevalence in patients diagnosed with PUJO, estimate reflux levels in patients with positive study, and limit serial voiding cystourethrogram (SVCU) or ultrasound cystography to selected patients (dilated ureter at ultrasound imaging and previous UTI). Materials and methods: Observational, retrospective study carried out in 74 patients undergoing surgery for PUJO. Information on sex, preoperative VUR screening, results (positive or negative for VUR), and reflux levels was collected. Results: 53 cases (71.6%) were male and 21 (28.4%) were female. Reflux screening was performed in 55 patients (74.3%), vs. 18 (24.3%) where no study was carried out. 16.2% of cases with VUR preoperative study were managed using ultrasound cystography. The preoperative study was positive in 6 out of the 73 patients (1 patient was excluded after being diagnosed with posterior urethral valves), which means VUR prevalence in patients already diagnosed with PUJO was 10.7%. Of the six cases, one case was grade I, two cases were grade II, one case was grade III, one case was grade IV, and one case was grade V. Conclusions: VUR has a slightly higher incidence in patients diagnosed with pyeloureteral junction obstruction than in the general population. Routine screening of vesicoureteral reflux is unnecessary, unless in case of previous urinary infection, dilated ureter at ultrasound imaging, or suspected secondary cause

Bladder Herniation as an Auto-Augmentation Technique in Bladder Exstrophy: Initial Experience in Patients with Small Bladder Plate.

OBJECTIVE: To present our long-term experience of bladder plate herniation technique in patients with bladder exstrophy epispadias complex (BEEC) and inadequate bladder plate. METHODS: Ten BEEC patients with inadequate bladder plates were referred. The bladder underlying fascia was opened and the exstrophic bladder was fixed above the peritoneal cavity to herniate the peritoneal contents beneath the bladder plate so that the abdominal pressure would be directly transferred to the posterior bladder wall; causing gradual bladder expansion and auto-augmentation. In 5 patients, the inguinal hernia was fixed to increase the pressure transferred to the exstrophic bladder. The bladder capacity was measured while the patient was crying and when the bladder was enlarged. Cystometry and voiding cystourethrogram were performed before the application of this technique and during the next 6 to 8 months, to determine the bladder capacity for further primary bladder closure. RESULTS: The bladder was enlarged during straining/crying without any complications. The average bladder capacity was increased about 2.5 to 3 times after 8 months of follow-up so that it was suitable for undergoing primary closure. None of the children needed bladder augmentation following the single-stage total BEEC reconstruction. CONCLUSION: This technique seems to be safe, effective, and feasible in patients with small-sized bladder and may be performed before the primary closure to increase the success rate. This technique may be effective in increasing the bladder capacity for staged bladder closure and bladder neck reconstruction without further need for bladder augmentation.

Retrograde CT urethrography using a power injector quantitatively reveals effects of bladder distension on urethral size in healthy male Beagle dogs.

Quantitative analysis of the normal retrograde urethrogram is well reported in radiography, but studies on CT urethrography are lacking. Recently, a method of retrograde CT urethrography using a power injector was described. The purpose of the current, prospective, analytical study was to quantify the urethral size of five, healthy, intact, male Beagle dogs using retrograde CT urethrography and a power injector. With the injection rate of the power injector set at 0.3 mL/s, 1 mL/kg of diluted contrast medium (15 mg I/mL) was injected, and a CT examination was performed. The state of the initial urethrogram taken was defined as "empty bladder." The same procedures were repeated with the injection of an additional 1 mL/kg of diluted contrast medium until the ureteral reflux was seen (distended bladder). There was a significant difference in volumes between the empty and distended bladder, but the membranous urethra showed the least difference (P = .0044) among the three regions (P < .0001 for the prostatic and penile urethra). Urethral diameters at six sites were measured from sagittal images, and the sites of measurements were adopted from the earlier radiographic studies. The most significant difference in the urethral diameters between the empty and distended bladder occurred at the cranial and middle prostatic urethra (P < .0001). The results of this study can be useful for interpreting the results of retrograde CT urethrography. Care must be taken when narrowing is suspected at the prostatic urethra, and if necessary, further distension of the urinary bladder should be tried.

Is computed tomography cystography indicated in children with pelvic fractures?

PURPOSE: Pelvic fracture evaluation with abdominopelvic computed tomography (CT) and formal CT cystography for rule out of urine bladder injury have been commonly employed in pediatric trauma patients. The additional delayed imaging required to obtain optimal CT cystography is, however, associated with increased doses of ionizing radiation to pelvic organs and represent a significant risk in the pediatric population for future carcinogenic risk. We hypothesized that avoidance of routine CT cystography among pediatric pelvic fracture victims would not result in an appreciable rate of missed bladder injuries and would aid in mitigating the radiation exposure risk associated with these additional images. METHODS: A retrospective cohort study involving blunt trauma pelvic fractures among pediatric trauma patients (age<14) between the years 1997 and 2016 was conducted utilizing the Israeli National Trauma Registry. Statistical analysis was performed using SAS statistical software version 9.4 via the tests of Chi-square test and two-sided Fisher's exact test. A p value of less than 0.05 was considered statistically significant. RESULTS: A total of 1072 children were identified from the registry for inclusion. Mean age of patients was 7.7 years (range 0-14) and 713 (66.5%) were male. Overall mortality in this population was 4.1% (44/1072). Only 2.1% (23) of pediatric patients with pelvic fractures had bladder injury identified, with just 9 children having intraperitoneal bladder rupture (0.8% of all the patients). CONCLUSION: The vast majority of blunt pediatric trauma victims with pelvic fractures do not have urine bladder injuries. Based on our study results we do not recommend the routine utilization of CT cystography in this unique population.

State-of-the-Art Renal Imaging in Children.

Imaging modalities for diagnosing kidney and urinary tract disorders in children have developed rapidly over the last decade largely because of advancement of modern technology. General pediatricians and neonatologists are often the front line in detecting renal anomalies. There is a lack of knowledge of the applicability, indications, and nephrotoxic risks of novel renal imaging modalities. Here we describe the clinical impact of congenital anomalies of the kidneys and urinary tract and describe pediatric-specific renal imaging techniques by providing a practical guideline for the diagnosis of kidney and urinary tract disorders.

Urosonografía miccional seriada en el diagnóstico y manejo de las válvulas de uretra posterior en pacientes pediátricos / Serial voiding urosonography in posterior urethral valve diagnosis and management in pediatric patients

Objetivos: Comunicar nuestra experiencia con la utilización de la urosonografía miccional seriada (UMS) para el diagnóstico y manejo de pacientes con válvulas de uretra posterior (VUP). Material y método: Estudio retrospectivo descriptivo en pacientes entre 0 a 14 años con sospecha de VUP en UMS realizada como primera prueba contrastada de la vía urinaria y con estudio cistoscópico posterior. Las variables se analizaron utilizando SPSSv22. Resultados: Fueron estudiados 18 pacientes (edad mediana de 6 meses). La mayoría de los pacientes (15) presentaban dilatación de la uretra posterior (diámetro medio de 9,56 mm) y diferencia entre uretra proximal y distal mayor de 2 mm. Trece casos tenían engrosamiento vesical y 9 RVU. Se diagnosticaron 15 casos de VUP, 1 caso de mucocele de uretra distal y 1 divertículo vesical que obstruía uretra. Se consiguió resección completa de las VUP en 10 pacientes (66,6%) en la primera cistoscopia. La UMS de control detectó un caso de resección incompleta por persistencia de dilatación de uretra posterior. Este caso y los 5 conocidos con resección incompleta se sometieron a una segunda cistoscopia y resección. El menor de los pacientes requirió una tercera resección y dilatación con balón de corte por estenosis residual. La creatinina media al diagnóstico fue 0,28 mg/dl. Conclusiones: La urosonografía miccional seriada (UMS) es una prueba complementaria útil en pacientes pediátricos con válvulas de uretra posterior. Su carácter dinámico y ventajas: ausencia de irradiación, seguridad y alta sensibilidad; la convierten en una prueba de imagen ideal para el diagnóstico y seguimiento de VUP

Objectives: Report our experience with the use of contrast-enhanced serial voiding urosonography (SVU) for posterior urethral valve (PUV) patient diagnosis and management. Materials and Methods: Descriptive retrospective study in 0- to 14-year-old patients with suspected PUV at SVU performed as a first contrast-enhanced urinary tract test with subsequent cystoscopic study. Variables were analyzed using SPSSv22. Results: 18 patients were studied (median age: 6 months). Most patients (15) presented posterior urethral dilatation (mean diameter: 9.56 mm) and a >2 mm gap between proximal and distal urethra. 13 cases had bladder thickening and 9 had VUR. 15 PUV cases, 1 case of distal urethral mucocele, and 1 case of bladder diverticulum obstructing the urethra were diagnosed. Complete PUV resection was performed in 10 patients (66.6%) at the first cystoscopy. The control SVU detected one case of recurrence due to persistence of posterior urethral dilatation. The recurrence case and the 5 incomplete resection cases were treated with a second cystoscopy and resection. The youngest patients required a third resection and cutting balloon dilatation due to residual stenosis. Mean creatinine levels at diagnosis were 0.28 mg/dl. Conclusions: Serial voiding urosonography (SVU) is a useful complementary test in pediatric patients with posterior urethral valve. Its dynamic nature and its advantages - absence of irradiation, safety, and high sens efitivity - make it an ideal imaging test for PUV diagnosis and follow-up

Timing of voiding cystourethrography after febrile urinary tract infection in children: a systematic review.

BACKGROUND: Despite a trend towards early voiding cystourethrography (VCUG) after febrile urinary tract infection (fUTI) in children, clinical guidelines do not comment on the optimal timing and current practice varies considerably. OBJECTIVE: To assess whether the detection rate of vesicoureteric reflux (VUR) in children depends on the time period of VCUG procedure after onset of antibiotic therapy. METHODS: MEDLINE, EMBASE and Cochrane Controlled Trials Register electronic databases were searched for eligible studies without language or time restriction (19 November 2018). Inclusion criteria were (1) patients <18 years of age; (2) VCUG performed in patients with fUTI after onset of antibiotic therapy either in the same patient population or in two or more different patient populations within one study at different time periods; and (3) with reported detection rate of VUR. The systematic review was carried out following the recommendations of the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. RESULTS: Of 4175 records, nine studies were included (number of patients, n=1745) for the main outcome prevalence of VUR by VCUG <8 days compared with VCUG ≥8 days after onset of antibiotic therapy. Pooled overall prevalence of VUR was not significantly different between the early and the late VCUG groups (risk ratio 0.98, 95% CI 0.81 to 1.19). Prevalence of VUR stratified by grade was not significantly different between the two groups. CONCLUSION: Early VCUG within 8 days after onset of antibiotic therapy does not affect the prevalence of VUR. TRIAL REGISTRATION NUMBER: CRD42018117545.