Contrast-enhanced voiding urosonography (ceVUS) with the intravesical administration of the ultrasound contrast agent Optison™ for vesicoureteral reflux detection in children: a prospective clinical trial

Contrast-Enhanced Ultrasound-Guided Endoscopic Retrograde Appendicitis Treatment-A Pilot Study on the Diagnostic and Therapeutic Efficacy in Uncomplicated Appendicitis

OBJECTIVE

To determine the diagnostic and therapeutic value of contrast-enhanced ultrasound-guided endoscopic retrograde appendicitis treatment (ERAT) in patients with uncomplicated appendicitis.

METHODS

A retrospective analysis was performed on clinical and ultrasound data collected from 105 pediatric patients with uncomplicated appendicitis between January 2020 and December 2023. The ultrasound findings before and after treatment, as well as postoperative follow-up and recurrence rates, were summarized and analyzed.

RESULTS

Successful intubation was achieved in 96 patients (91.4%). The conventional ultrasound appendix visualization rate was 39.6% (38/105), while the appendix visualization rate after contrast-enhanced ultrasound-guidance was 75% (72/105). Contrast-enhanced ultrasound revealed various appendiceal morphologic changes in 89 patients, such as twisting, tortuosity, stiffness, rough inner wall, dilated diameter, and narrowing of the lumen. Additionally, local filling defects, which indicated the presence of fecal stones or debris deposition, were noted in 68 patients. No leakage of the contrast agent occurred. Post-treatment evaluation showed improvement in appendiceal diameter, lumen, and filling defects (P < .01). The follow-up rate was 82 of 89 patients (92.1%), all of whom recovered well without a recurrence. The recurrence rate was 7.9% (7/89). Among the patients with recurrences, five patients resolved after medical treatment and two patients recovered after surgical treatment.

CONCLUSION

Contrast-enhanced ultrasound-guided ERAT for uncomplicated appendicitis is safe and effective. Specifically, the appendix is increased, which facilitates an evaluation of therapeutic effectiveness. ERAT serves as a valuable supplementary modality to determine the need for surgical treatment of acute appendicitis, which is of significant clinical value.

Imaging of Vesicoureteral Reflux: AJR Expert Panel Narrative Review

Vesicoureteral reflux (VUR) is a common congenital anomaly of the urinary tract that can present with collecting system dilation or as a febrile infection. VUR can lead to permanent renal sequelae requiring surgery but can also spontaneously resolve without complication. Therefore, recognizing patient populations who warrant imaging for screening, confirmation, or ongoing surveillance for VUR is important, as is avoiding overdiagnosis. In the appropriate patient populations, an accurate diagnosis of VUR allows early treatment and prevention of pyelonephritis and scarring. Various imaging modalities are available to diagnose and grade VUR, including voiding cystourethrography, radionucleotide cystography, and contrast-enhanced voiding urosonography (ceVUS). The objective of this article is to summarize the current understanding of VUR diagnosis and management and to discuss these imaging modalities' strengths and pitfalls. Considerations include indications for VUR imaging, patient preparation, conduct of the examination, issues related to radiologic reporting, and cost-effectiveness. An emphasis is placed on ceVUS, which is the most recently introduced of the three imaging modalities and is receiving growing support among pediatric radiologists.

The Intrarenal Reflux Diagnosed by Contrast-Enhanced Voiding Urosonography (ceVUS): A Reason for the Reclassification of Vesicoureteral Reflux and New Therapeutic Approach?

Vesicoureteral reflux (VUR) is defined as the urine backflow from the urinary bladder to the pyelo-caliceal system. In contrast, intrarenal reflux (IRR) is the backflow of urine from the renal calyces into the tubulointerstitial space. VURs, particularly those associated with IRR can result in reflux nephropathy when accompanied by urinary tract infection (UTI). The prevalence of IRR in patients with diagnosed VUR is 1-11% when using voiding cystourethrography (VCUG), while 11.9-61% when applying the contrast-enhanced voiding urosonography (ceVUS). The presence of IRR diagnosed by VCUG often correlates with parenchymal scars, when diagnosed by a 99mTc dimercaptosuccinic acid scan (DMSA scan), mostly in kidneys with high-grade VURs, and when diagnosed by ceVUS, it correlates with the wide spectrum of parenchymal changes on DMSA scan. The study performed by both ceVUS and DMSA scans showed IRRs associated with non-dilated VURs in 21% of all detected VURs. A significant difference regarding the existence of parenchymal damage was disclosed between the IRR-associated and IRR-non-associated VURs. A higher portion of parenchymal changes existed in the IRR-associated VURs, regardless of the VUR grade. That means that kidneys with IRR-associated VURs represent the high-risk group of VURs, which must be considered in the future classification of VURs. When using ceVUS, 62% of places where IRR was found were still unaffected by parenchymal changes. That was the basis for our recommendation of preventive use of long-term antibiotic prophylaxis until the IRR disappearance, regardless of the VUR grade. We propose a new classification of VURs using the ceVUS method, in which each VUR grade is subdivided based on the presence of an IRR.

Vesicoureteral reflux by contrast ultrasound, comparison with voiding and retrograde urethrocystography: A prospective accuracy study

INTRODUCTION

Diagnosis of vesicoureteral reflux (VUR) plays an important role in the management and follow-up of children presenting with urinary tract infection. This study compared voiding uronosography (VUS) as a diagnostic method for the diagnosis of VUR with the "gold standard", voiding or micturating cystourethrography (MCU). The objective of the study is not only to compare the effectiveness of both methods, but also to assess the feasibility of implementing VUS technically and economically in a large tertiary radiology center in South America.

MATERIALS AND METHOD

This was a prospective accuracy study that include 41 patients (a total of 85 ureteral units) aged between 1 month and 16 years. VUS was performed in an alternative form as regular MCU, by injecting microbubble contrast solution (SonoVue©) into the bladder through an intermittent catheter and evaluating the presence of reflux with ultrasound. MCU was always performed immediately after VUS. One pediatric radiologist evaluated all VUS exams, while a second independent pediatric radiologist evaluated all MCU exams, with both blinded to each other's assessments.

RESULTS

Comparing VUS with MCU in the diagnosis of VUR, we observed a sensitivity of 92.3 % (95 % CI 74.9-99.1 %), specificity of 98.3 % (95 % CI 90.9-100 %), positive predictive value of 96.0 % (95 % CI 79.6-99.9 %), negative predictive value of 96.7 % (95 % CI 88.5-99.6 %) and a Kappa of 0.916 (0.822-1.000). When comparing the VUR grading between VUS and MCU the agreement between the two methods was high with a Kendall's Tau-b > 0.9. VUS failed to diagnose two grade 1 VUR reflux cases in teenagers while diagnosing one grade 4 VUR in a very dilated kidney-ureter unit, which was missed on MCU. VUS and MCU had similar costs when considering the price of the ultrasound contrast agent.

DISCUSSION

VUS is a reliable alternative method to MCU for the diagnosis of VUR with the advantages of not exposing the child to ionizing radiation and potentially being more accessible due to the greater availability of ultrasound equipment. Limitations to this study include the usage of a single ultrasound equipment, which limits its generalizability and not evaluating the interobserver variability.

CONCLUSION

Consideration should be given to implementing VUS for the diagnosis of VUR, particularly in centers without fluoroscopy equipment available, since the exam's performance and cost are comparable to those of the MCU.

Parental perception of contrast enhanced voiding ultrasonography urodynamics vs fluoroscopic urodynamics

INTRODUCTION/OBJECTIVES

Contrast enhanced voiding ultrasonography (ceVUS) has not been widely reported to be used during video urodynamics (UDS). We previously reported on the feasibility of this. In this study, we aimed to understand how parents perceived their child's experience of undergoing ceVUS during UDS compared to fluoroscopic (fluoro) UDS.

METHODS

Children who underwent both fluoro UDS and ceVUS UDS were recruited. Parents were asked to complete a questionnaire to evaluate their experience with both studies. Demographics including gender, age at study, and diagnosis were collected to account for differences in perception. Statistical analysis was performed.

RESULTS

53 patients were included: 31 girls, 22 boys. Diagnoses included myelomeningocele (67.9%), low/tethered cord (13.2%), closed spinal dysraphism (9.4%), posterior urethral valve (1.9%), cloacal anomaly (1.9%), caudal regression (1.9%), myeloschisis (1.9%), and cerebral palsy (1.9%). There was no statistical difference in mean age at fluoro UDS and ceVUS UDS (77.3 months vs 99.7 months respectively, p = 0.09). All 53 parents (100%) were satisfied/very satisfied with their ceVUS experience; 48 parents (90.6%) preferred ceVUS, 3 parents (5.7%) preferred fluoro UDS, and 2 (3.8%) were neutral. On average, parents perceived ceVUS to be more comfortable (72.7%) and produce better results (67.4%) than fluoro UDS. The majority felt that both studies allowed the same contact with their child (52.3%) and took the same amount of time (50.0%). However 29.5% felt ceVUS was faster and 34.1% felt ceVUS allowed more contact with their child (Fig. 1). 26 parents (49.1%) specifically noted no radiation as the reason why they preferred ceVUS over fluoro. The average age at ceVUS UDS was younger in those who preferred ceVUS UDS compared to those who preferred fluoro UDS (94.6 months vs 180.0 months, p = 0.03). The average age at fluoro UDS was younger in those who preferred ceVUS UDS vs fluoro UDS (73.1 months vs 144 months, p = 0.03). Gender's influence on preference approached significance (p = 0.07); all 3 parents who preferred fluoro UDS had male children.

CONCLUSIONS

The majority of parents preferred ceVUS over fluoro UDS. ceVUS was perceived to be more comfortable and provide better results. Many parents highlighted no radiation and no fluoroscopic machinery as factors in preference of ceVUS over fluoro. The parents who preferred ceVUS UDS had children who had both studies done at an earlier age compared to the parents who preferred fluoro UDS.

Application of contrast-enhanced ultrasound in the surgical treatment of vesicoureteral reflux in children

BACKGROUND

To determine the utility of contrast-enhanced voiding urography (CeVUS) in the treatment of vesicoureteral reflux (VUR) through ureterovesical reimplantation in children.

METHODS

A total of 159 children with recurrent urinary tract infections were selected for CeVUS and voiding cystourethrography (VCUG) from December 2018 to December 2020, among whom 78 patients were eventually diagnosed with VUR. Overall, 60 pyelo-ureteric units (PUUs) were operated according to surgical indications. Accordingly, we determined the general clinical characteristics of all children, obtained two-dimensional ultrasound images, assessed the reflux status of children using the contrast-enhanced technique, and compared the obtained results via CeVUS and VCUG. Both imaging modalities were reperformed at 6, 12, and 18 months after surgery to evaluate postoperative outcomes. In particular, we assessed the consistency of the evaluation and calculated the diagnostic efficacy of CeVUS for different levels of reflux at different time points.

RESULTS

CeVUS showed considerable efficacy in the diagnosis of children with VUR. Notably, the diagnostic results of both CeVUS and VCUG achieved high agreement, with a kappa value of 0.966 (P < 0.001). The results of our follow-up at different stages and evaluation of postoperative efficacy revealed that CeVUS possessed substantial diagnostic efficacy and good consistency with VCUG.

CONCLUSION

CeVUS is an accurate and safe examination, with considerable clinical significance for diagnosing VUR in children, determining the treatment approach, conducting follow-up during treatment, and evaluating subsequent treatment outcomes.

Effectiveness of various treatment modalities in children with vesicoureteral reflux grades II-IV: a systematic review and network meta-analysis

BACKGROUND

Vesicoureteral reflux (VUR) is one of the most common risk factors of urinary tract infection (UTI) among children. Various treatment modalities including antibiotic prophylaxis, surgical or endoscopic corrections and conservative treatment were used depending on the severity of VUR. The aim of this study is to compare the effectiveness of these treatment modalities in children with VUR grades II-IV by conducting a systematic review and network meta-analysis.

METHODS

A systematic search from different databases was performed from their earliest records to December 2022 without any language restriction. Only randomised controlled trials were included in this study. Effectiveness of treatment modalities was mainly compared by UTI. Other outcomes for renal scarring and resolution by renal units were also measured between treatments.

RESULTS

A total of 11 studies with 1447 children were included in this study. While comparing with antibiotic prophylaxis in network meta-analysis for UTI recurrence, surgical treatment probably lowers the rate of UTI recurrence (Log OR -0.26, 95% CI -0.54 to 0.02, high quality). However, endoscopic treatment (Log OR 0.2, 95% CI -1.41 to 1.81, high quality) and conservative treatment (Log OR 0.15, 95% CI -0.45 to 0.75, high quality) revealed probably inferior to antibiotic treatment.

CONCLUSION

Both pairwise and network meta-analytic results probably showed no difference between the treatments in terms of their impact on UTI recurrence, progression of previous renal scars, or formation of new renal scars in children with VUR grades II-IV. These findings may offer a better understanding of each treatment and evidence-based suggestions for the choice of treatment, which should be individualised and based on the patient's risk factors.

Viability of contrast-enhanced voiding urosonography as an alternative to fluoroscopy during video urodynamics

Pediatric urodynamic studies are performed to evaluate bladder function, commonly in conjunction with a voiding cystourethrogram (VCUG). Contrast-enhanced voiding urosonography (CeVUS) has been approved in the evaluation of vesicoureteral reflux and has been shown to have equal or superior diagnostic value to VCUG. In this technical innovation, we have shown that ultrasound contrast agent microbubbles are compatible with the equipment used for urodynamic evaluation. We have also shown that it is feasible to use contrast ultrasound in pediatric urodynamic examinations. The purpose of our study was to assess the technical feasibility of CeVUS during urodynamics with an in vitro test followed by a vivo evaluation. This single-center prospective study enrolled 25 patients aged 0-18 years who underwent CeVUS instead of VCUG at their regularly scheduled appointment. During the in vitro saline experiment, the radiologic and urologic equipment were found to be compatible. Microbubbles were observed at flow rates of 10 and 20 ml/min.

A narrative review on the applications of intracavitary contrast-enhanced ultrasonography in pediatric lower genitourinary anomalies

Purpose

We mainly aimed to perform a narrative review of clinical applications of the three intracavitary contrast-enhanced ultrasonography (CEUS) including contrast-enhanced voiding urosonography (ceVUS), contrast-enhanced retrograde urethrosonography (ceRUG), and contrast-enhanced genitosonography (ceGS) in pediatric lower genitourinary anomalies.

Method

A literature search in the PubMed and Web of Science databases was conducted up to 1 July 2022 on all studies published in English using the search terms "contrast-enhanced voiding urosonography", "contrast-enhanced retrograde urethrosonography", and "contrast-enhanced genitosonography". Trials were limited to pediatric subjects (ages ≤18 years) with no time restrictions. The inclusion criteria were studies on ceVUS, ceRUG, and ceGS to evaluate pediatric lower genitourinary anomalies. Two independent authors summarized the included articles.

Results

Finally, a total of 48 original articles and 6 case reports or case series were included, of which 50 (93%) were only relevant to ceVUS, 3 (5%) articles involved ceGS, while only one (2%) article involved ceRUG, and 87% of the applications of ceVUS were focused on vesicoureteral reflux (VUR). We also searched 24 related reviews, of which 20 involved ceVUS in diagnosing VUR and 4 involved ceRUG and ceGS for other lower genitourinary anomalies.

Conclusion

Intracavitary CEUS including ceVUS, ceRUG, and ceGS in pediatrics has many advantages over other radiological examinations in diagnosing lower genitourinary anomalies. Although ceVUS is widely used in detecting VUR, ceRUG and ceGS have also become promising techniques for evaluating the urethral pathologies and urogenital sinus.

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.

Application of urodynamics combined with contrast-enhanced ultrasound in evaluation of the urinary tract in patients with low bladder compliance and vesicoureteric reflux who underwent bladder augmentation alone

We assessed the use of common urodynamics (CUD) combined with contrast-enhanced ultrasound (CEUS) to investigate the efficacy and durability of sigmoid cystoplasty alone in patients with low bladder compliance associated with vesicoureteric reflux (VUR). In this study, we recruited 25 patients with low bladder compliance and VUR who underwent bladder augmentation without antireflux surgery at our institutions between June 2017 and June 2021. The bladder condition and VUR grade were assessed preoperatively and postoperatively via CUD combined with CEUS. The mean follow-up period was 2.6 years. CUD showed significant improvement in bladder capacity and compliance and a decrease in intravesical pressure after sigmoid cystoplasty. CEUS demonstrated resolution of VUR compared with preoperative assessment. Of the 25 patients who had various degrees of reflux, VUR was eliminated in 18 patients and reduced to a lower grade in the remaining seven patients. CUD combined with CEUS is accurate and safe. They are invaluable and reliable tools for morphological and functional evaluations of the entire urinary tract in patients with low bladder compliance and 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.

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

INTRODUCTION

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Spectrum of Parenchymal Changes in Kidneys Affected by Intrarenal Reflux, Diagnosed by Contrast-Enhanced Voiding Urosonography and DMSA Scan

PURPOSE

To describe the parenchymal defects in kidneys with intrarenal reflux (IRR) diagnosed using contrast-enhanced voiding urosonography (ceVUS) and ^99mTc-DMSA scintigraphy (DMSA scan).

MATERIALS AND METHODS

A group of 186 uretero-renal units (URUs) was analyzed using ceVUS and DMSA scans: 47 without vesicoureteral reflux (VUR) (group A) and 139 with VURs, comprising 73 VURs without (group B), and 66 with IRR (group C). VURs included non-dilating (grades I-II), mildly non-dilating (grade III), and non-dilating (grades IV-V) grades. The parenchymal changes were analyzed using a DMSA scan.

RESULTS

The median age for VUR diagnosis was 16.5 months in girls, and 8.5 months in boys (Z = 3.9; p = 0.001). IRR occurred in 51.4% of boys and in 25.9% of girls (χ² = 12.4; p < 0.001). The non-dilating VUR occurred in 44% of boys and 24.1% of girls (χ² = 7.7; p = 0.005). IRRs characterized upper and lower renal segments (81.8 and 63.6%) and middle segments (33.3%). Both incidence and increase in IRR correlated with the grade of VUR (p < 0.001). The incidence of reduced DMSA signal was statistically different among groups A + B and C, but not between groups A and B (χ² = 32.2; p < 0.001). No statistically significant relationship existed between the reduced DMSA signal and the grade of VUR in group C. The reduced DMSA signal appeared in 9.9% positions in kidneys from group A, 14% from group B, and 32% from group C. Out of all 118 IRRs, 38.1% had reduced and 61.9% had normal DMSA signal. Among 11 parenchymal scars found in all three groups, 2 belonged to group B, 9 to group C, while group A had no scars.

CONCLUSION

The parenchymal changes are the most prominent in the group with IRR, but they do not significantly differ among kidneys with different grades of VUR. VURs of higher grades are associated with a higher incidence of IRR and early clinical presentation. Scars can also appear in lower-grade VURs accompanied by IRR. Boys with VUR have earlier clinical presentation than girls, as they have significantly higher grades of VUR with a higher proportion of IRRs. Therefore, we suggest a subdivision of VURs into those with IRR and abundant parenchymal damage, and those without IRR and less parenchymal damage.

Translational research in pediatric contrast-enhanced ultrasound

The role of contrast-enhanced ultrasound (CEUS) imaging is being widely explored by various groups for its use in the pediatric population. Clinical implementation of new diagnostic or therapeutic techniques requires extensive and meticulous preclinical testing and evaluation. The impact of CEUS will be determined in part by the extent to which studies are oriented specifically toward a pediatric population. Rather than simply applying principles and techniques used in the adult population, these studies are expected to advance and augment preexisting knowledge with pediatric-specific information. To further develop this imaging modality for use in children, pediatric-focused preclinical research is essential. In this paper we describe the development and implementation of the pediatric-specific preclinical animal and phantom models that are being used to evaluate CEUS with the goal of clinical translation to children.

Contrast-enhanced genitosonography and colosonography: emerging alternatives to fluoroscopy

Imaging plays a crucial role in evaluating newborns and infants with cloacal and urogenital malformations. Contrast-enhanced genitosonography (ceGS) and contrast-enhanced colosonography (ceCS) are sensitive and radiation-free alternatives to fluoroscopic genitography and colography for diagnosis and surgical planning. These imaging techniques are performed by instilling a US contrast agent into specific body cavities to define the genitourinary and colorectal anatomy. This review article presents the experience with ceGS and ceCS applications in children, focusing on the background, examination technique, and interpretation of imaging findings, as well as strengths and weaknesses compared to conventional techniques.

Contrast-enhanced voiding urosonography, part 1: vesicoureteral reflux evaluation

Contrast-enhanced voiding urosonography (ceVUS) is a well-established, sensitive and safe ultrasound (US) modality for detecting and grading vesicoureteral reflux (VUR) and urethral imaging in children. Nearly three decades of remarkable advances in US technology and US contrast agents have refined ceVUS's diagnostic potential. The recent approval of Lumason/SonoVue in the United States, Europe and China for pediatric intravesical applications marked the beginning of a new era for this type of contrast US imaging. Consequently, the use of ceVUS in children has expanded to multiple places around the globe. In the first part of this review article, we describe the current experience in the use of ceVUS for VUR evaluation, with an emphasis on historical background, examination technique, image interpretation and diagnostic accuracy. In the second part, we will present the role of ceVUS for urethral imaging in children.

Pediatric contrast-enhanced ultrasound: optimization of techniques and dosing

When performing contrast-enhanced ultrasound (CEUS), ultrasound (US) scanner settings, examination technique, and contrast agent dose and administration must be optimized to ensure that high-quality, diagnostic and reproducible images are acquired for qualitative and quantitative interpretations. When carrying out CEUS in children, examination settings should be tailored to their body size and specific indications, similar to B-mode US. This review article details the basic background knowledge that is needed to perform CEUS optimally in children, including considerations related to US scanner settings and US contrast agent dose selection and administration techniques.

Pediatric contrast-enhanced ultrasound: shedding light on the pursuit of approval in the United States

For two decades, pediatric contrast US has been well accepted throughout Europe and other parts of the world outside the United States because of its high diagnostic efficacy and extremely favorable safety profile. This includes intravenous (IV) administration, contrast-enhanced US (CEUS) and the intravesical application, contrast-enhanced voiding urosonography (ceVUS). However, the breakthrough for pediatric contrast US in the United States did not come until 2016, when the U.S. Food and Drug Administration (FDA) approved the first pediatric indication for a US contrast agent. This initial approval covered the use of Lumason (Bracco Diagnostics, Monroe Township, NJ) for the evaluation of focal liver lesions via IV administration in children. A second pediatric indication followed shortly thereafter, when the FDA extended the use of Lumason for assessing known or suspected vesicoureteral reflux via intravesical application in children. Both initial pediatric approvals were granted without prospective pediatric clinical trials, based instead on published literature describing favorable safety and efficacy in children. Three years later, in 2019, the FDA approved Lumason for pediatric echocardiography following a clinical trial involving a total of 12 subjects at 2 sites. The story of how we achieved these FDA approvals spans more than a decade and involves the extraordinary dedication of two professional societies, namely the International Contrast Ultrasound Society (ICUS) and the Society for Pediatric Radiology (SPR). Credit also must be given to the FDA staff for their commitment to the welfare of children and their openness to compelling evidence that contrast US is a safe, reliable, radiation-free imaging option for our pediatric patients. Understanding the history of this approval process will impact the practical application of US contrast agents, particularly when expanding off-label indications in the pediatric population. This article describes the background of the FDA's approval of pediatric contrast US applications to better illuminate the potential pathways to approvals of future indications.

Contrast-enhanced ultrasound: a comprehensive review of safety in children

Contrast-enhanced ultrasound (CEUS) has been increasingly used in pediatric radiology practice worldwide. For nearly two decades, CEUS applications have been performed with the off-label use of gas-containing second-generation ultrasound contrast agents (UCAs). Since 2016, the United States Food and Drug Administration (FDA) has approved the UCA Lumason for three pediatric indications: the evaluation of focal liver lesions and echocardiography via intravenous administration and the assessment of vesicoureteral reflux via intravesical application (contrast-enhanced voiding urosonography, ceVUS). Prior to the FDA approval of Lumason, numerous studies with the use of second-generation UCAs had been conducted in adults and children. Comprehensive protocols for clinical safety evaluations have demonstrated the highly favorable safety profile of UCA for intravenous, intravesical and other intracavitary uses. The safety data on CEUS continue to accumulate as this imaging modality is increasingly utilized in clinical settings worldwide. As of August 2021, 57 pediatric-only original research studies encompassing a total of 4,518 children with 4,906 intravenous CEUS examinations had been published. As in adults, there were a few adverse events; the majority of these were non-serious, although very rarely serious anaphylactic reactions were reported. In the published pediatric-only intravenous CEUS studies included in our analysis, the overall incidence rate of serious adverse events was 0.22% (10/4,518) of children and 0.20% (10/4,906) of all CEUS examinations. Non-serious adverse events from the intravenous CEUS were observed in 1.20% (54/4,518) of children and 1.10% (54/4,906) of CEUS examinations. During the same time period, 31 studies with the intravesical use of UCA were conducted in 12,362 children. A few non-serious adverse events were encountered (0.31%; 38/12,362), but these were most likely attributable to the bladder catheterization rather than the UCA. Other developing clinical applications of UCA in children, including intracavitary and intralymphatic, are ongoing. To date, no serious adverse events have been reported with these applications. This article reviews the existing pediatric CEUS literature and provides an overview of safety-related information reported from UCA uses in children.

Integrated Ultrasound With Urodynamics Illustrates Effect of Bladder Volume on Upper Tract Dilation: Should we Trust Surveillance Ultrasounds?

OBJECTIVE

To evaluate if ultrasound during urodynamics (uUS) will show that traditional ultrasound (tUS) routinely underestimates the potential magnitude of upper tract dilation (UTD).

METHODS

Prospective pilot study of 10 consecutive patients ≥ 5 years of age undergoing same day uUS and tUS. Using randomized images, the study pediatric radiologist determined anterior-posterior renal pelvic diameter (APD), bladder volume, vesicoureteral reflux (VUR) and UTD grades. A single pediatric urologist determined urodynamic bladder capacity and assigned either hostile, intermediate, abnormal but safe, or normal national spina bifida patient registry classification (NSBPR).

RESULTS

Bladder volume on tUS was significantly smaller than final bladder volume on uUS (180 vs 363 ml: P<.001). On average, patient reported maximum catheterized/voided volumes were also 82 ml greater than final bladder capacity on uUS. UTD was upgraded in 25% of kidneys and APD increased by 0.6 cm on uUS over that seen on tUS (P=.001). Units with VUR had greater increases in APD (1.2 P=.007 vs. 0.3 cm P=0.06). Changes in APD stratified by NSBPR revealed average increases of up to 1.3 cm.

CONCLUSION

Despite instructions to the contrary, patients come for tUS with a relatively empty bladder as compared to either their urodynamic or patient-reported capacity. This translates to a significant underestimation of UTD with tUS, most notably in those with VUR. Alternatives to traditional protocols include insisting patients wait until their bladder is truly full for tUS, retrograde filling their bladder, or performing uUS. Accurate assessment of UTD severity may help guide long term management.

Contrast-enhanced voiding urosonography in the assessment of vesical-ureteral reflux: the time has come

Vesicoureteral reflux (VUR) is a pathological condition contradistinguished by monolateral or bilateral retrograde flow of urine from the bladder to the ureter and to the kidney. If not properly recognized and treated, VUR can potentially be associated to several complications such as recurrent infections and possible secondary scars with Chronic Kidney Disease (CKD). Furthermore, it represents an important risk factor for nephrovascular hypertension. During the last 20 years, the diagnostic approach to this entity has passed through several, drastic changes: indeed, since its introduction in 1994 contrast-enhanced voiding urosonography (ceVUS) has gradually accompanied the voiding cystourethrography (VCUG) as alternative imaging technique for the diagnosis and staging of VUR. Despite a large number of papers has strongly encouraged its use in clinical practice, due to the lack of ionizing radiations and its high sensitivity rate, to date almost all the guidelines only include the VCUG for VUR diagnosis. The introduction of technologically advanced US software and the approval of the intravesical administration of ultrasound contrast agents by the Food and Drug Administration (FDA) and by the European Medicine Agency (EMA) have to induce the Scientific Community to a deep revaluation of the role of ceVUS in the diagnosis and follow-up of VUR: urosonography might extensively replace VCUG as the reference method, reserving to cystourethrography a role in the most complex anatomic settings for pre-surgical evaluation.

Paediatric gastrointestinal and hepatobiliary radiology: why do we need subspecialists, and what is new?

We present the case for subspecialisation in paediatric gastrointestinal and hepato-pancreatico-biliary radiology. We frame the discussion around a number of questions: What is different about the paediatric patient and paediatric gastrointestinal system? What does the radiologist need to do differently? And finally, what can be translated from these subspecialty areas into everyday practice? We cover conditions that the sub-specialist might encounter, focusing on entities such as inflammatory bowel disease and hepatic vascular anomalies. We also highlight novel imaging techniques that are a focus of research in the subspecialties, including contrast-enhanced ultrasound, MRI motility, magnetisation transfer factor, and magnetic resonance elastography.

Evaluation of the Diagnostic Value of Contrast-Enhanced Voiding Urosonography with Regard to the Further Therapy Regime and Patient Outcome-A Single-Center Experience in an Interdisciplinary Uroradiological Setting

Background and Objectives: Vesicoureteral reflux (VUR) describes a common pediatric anomaly in pediatric urology with a prevalence of 1-2%. In diagnostics, in addition to the gold standard of voiding cystourethrography (VCUG), contrast-enhanced urosonography (ceVUS) offers a radiation-free procedure, which, despite its advantages, is not yet widely used. In the present single-center study, subsequent therapeutic procedures and outcomes after ceVUS of 49 patients were investigated. The aim of the study is to investigate the efficacy of ceVUS with the intention of broader clinical implementation. Materials and Methods: Between 2016 and 2020, 49 patients were retrospectively included and received a ceVUS to evaluate VUR. With a distribution of 47:2 (95.9%), a clear female predominance was present. The age of the patients varied between 5 months and 60 years at the time of ceVUS. All examinations were all performed and subsequently interpreted by a single experienced radiologist (EFSUMB level 3). Results: Compared to intraoperative findings, ceVUS shows a sensitivity of 95.7% with a specificity of 100%. Allergic reactions to the contrast medium could not be observed. Conclusion: With its high sensitivity and intraoperative validation, ceVUS offers an excellent alternative to VCUG, the gold standard in the diagnosis of VUR. In addition, ceVUS is a radiation-free examination method with a low risk profile that offers an exceptional diagnostic tool in the diagnostic clarification of recurrent urinary tract infections with the suspected diagnosis of VUR and should also be included in the consideration of a diagnosis next to the established VCUG, especially in younger children.

Intrarenal Reflux in the Light of Contrast-Enhanced Voiding Urosonography

Purpose: The aim of this study was to analyze the incidence of intrarenal reflux (IRR) among vesicoureteral refluxes (VURs), diagnosed by contrast-enhanced voiding urosonography (ceVUS), to define VURs which are positive to IRR and their locations in the kidney. Materials and Methods: Seventy patients with VURs, including 103 uretero-renal units (URUs) with VURs of grades II-V (37 URUs were excluded because of renal anomalies or absence of VUR) were examined with ceVUS due to recurrent febrile UTI or first febrile UTI accompanied by abnormalities on renal ultrasonography. Patients were examined on GE Logiq S8 ultrasound machine, using second generation of ultrasound contrast agent. Results: Out of 103 VURs, 51 (49.51%) had IRR regardless the grade of VUR, showing increase in IRR incidence with VUR severity (p < 0.0001). The median age at the time of IRR diagnosis was 5 months (IQR, 3-14.3), whereas in patients without IRR, it was 15.5 months (IQR, 5-41.5), (p = 0.0069). IRR was most common in superior pole (80%), followed by inferior pole (62.7%), and middle segments (37%), and to all segments (27%) (p < 0.0001). Conclusion: In the present study, patients with IRR-associated VUR showed earlier clinical presentation. The distribution of IRRs corresponded to the natural distribution of composed papillae types II and III, while the incidence of IRR increased with severity of VUR. Further clinical studies may point to the importance of considering IRR in the future classification of VUR.

Impact of Implementing Contrast-Enhanced Ultrasound for Antegrade Nephrostogram After Percutaneous Nephrolithotomy

OBJECTIVES

To report results from a quality improvement (QI) project evaluating diagnostic performance, hospital resource use, and patient response data for postoperative contrast-enhanced ultrasound (CEUS) antegrade nephrostogram after percutaneous nephrolithotomy.

METHODS

For this Health Insurance Portability and Accountability Act-compliant, Institutional Review Board-approved study, QI data were deidentified and analyzed. On the first postoperative day after percutaneous nephrolithotomy, patients underwent both CEUS and fluoroscopic antegrade nephrostogram. For CEUS, 1.0 mL of Lumason (sulfur hexafluoride lipid type A microspheres; Bracco Diagnostics, Inc, Monroe Township, NJ) was injected via an indwelling nephrostomy tube, with ureteral patency confirmed by identifying intravesical ultrasound (US) contrast. Diagnostic performance for ureteral patency and contrast extravasation was calculated (with fluoroscopy as the reference standard). The examination time, room time, physician time, hospital costs, and patient response data were compared. The mean, standard deviation, 95% confidence interval, differences in mean, and 95% confidence interval of differences were calculated.

RESULTS

Eighty-one examinations were performed in 73 patients during the QI period. The sensitivity and specificity of CEUS for ureteral patency were 96% and 57%, respectively. There was no significant difference in time metrics between modalities, and the cost analysis showed lower direct and indirect costs for CEUS. Patient responses revealed lower levels of comfort for CEUS relative to fluoroscopy, without significant differences in reported pain or effort levels.

CONCLUSIONS

Contrast-enhanced US showed very high sensitivity for ureteral patency; the relatively low specificity may have resulted from false-negative results in fluoroscopy. The hospital costs and resource use of CEUS compared favorably to fluoroscopy. Contrast-enhanced US also offers inherent advantages, including portability and lack of ionizing radiation.

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

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

Contrast-enhanced voiding urosonography (CEVUS) as a novel technique for evaluation in a case of male urethral diverticulum

Male urethral diverticulum is an uncommon entity, the abnormality being more frequently encountered in females. The pathology may be congenital or acquired and the more frequent acquired type usually occurs following trauma. Afflicted patients usually lack specific symptoms, although in a few instances, symptoms of lower urinary tract obstruction, calculi, or infection may prevail. Imaging investigations utilizing a composite Retrograde urethrography (RGU)– Voiding cystourethrography (VCUG) protocol are accepted as standard approach and ultrasound is considered a secondary supplementary investigation. However, recent literature reports the utility of contrast-enhanced ultrasound (CEUS) as a novel technique in the evaluation of urinary bladder and urethra, for vesico-ureteric reflux (VUR) in children and for urethral diverticula in women. We report a case of acquired post-traumatic urethral diverticulum in an adult male patient and document a relatively unexplored novel application of contrast enhanced voiding uro-sonography (CEVUS) for the evaluation of this malady.

Three Decades of Ultrasound Contrast Agents: A Review of the Past, Present and Future Improvements

Initial reports from the 1960s describing the observations of ultrasound contrast enhancement by tiny gaseous bubbles during echocardiographic examinations prompted the development of the first ultrasound contrast agent in the 1980s. Current commercial contrast agents for echography, such as Definity, Optison, Sonazoid and SonoVue, have proven to be successful in a variety of on- and off-label clinical indications. Whereas contrast-specific technology has seen dramatic progress after the introduction of the first approved agents in the 1990s, successful clinical translation of new developments has been limited during the same period, while understanding of microbubble physical, chemical and biologic behavior has improved substantially. It is expected that for a successful development of future opportunities, such as ultrasound molecular imaging and therapeutic applications using microbubbles, new creative developments in microbubble engineering and production dedicated to further optimizing microbubble performance are required, and that they cannot rely on bubble technology developed more than 3 decades ago.

The Use of Contrast-enhanced Ultrasound in Pediatrics: A Case Series

As the use of contrast-enhanced ultrasound (CEUS) is still relatively novel but quickly expanding, we would like to present a series of clinical cases where CEUS was used in diagnostics of pediatric patients. The presented cases include kidney trauma, non-Hodgkin's lymphoma with secondary liver deposits, renal cortical cysts, retropharyngeal abscess, necrotizing pancreatitis, and vesicoureteral reflux. The wide range of the presented cases demonstrates CEUS' multipurpose use, which, together with its other useful attributes, especially its favorable safety profile, makes it an excellent diagnostic tool.

The learning curve of contrast-enhanced 'microbubble' voiding urosonography-validation study

INTRODUCTION

Vesicoureteral reflux (VUR) is a common pediatric urologic condition associated with urinary tract infection and pyelonephritis. It can be diagnosed via fluoroscopic voiding cystourethrogram (VCUG) and, more recently, contrast-enhanced voiding ultrasonography (ceVUS), which does not expose the patient to ionizing radiation. Voiding urosonography contrast agents used for the diagnosis of VUR have been widely available in Europe but were approved by the Food and Drug Administration for use in the United States only in 2016.

OBJECTIVE

The objective was to optimize a protocol and compare the diagnostic performance of ceVUS to fluoroscopic VCUG in an academic medical center naïve to previous use of contrast-enhanced voiding urosonography.

STUDY DESIGN

Thirty-nine patients referred for clinically indicated evaluation of VUR were enrolled between September 2016 and March 2017. Patients underwent contrast-enhanced ultrasonography with prediluted Lumason and under the same catheterization underwent fluoroscopic VCUG. Comparative grading was performed by pediatric radiologists on-site at the time of examination.

RESULTS

Reflux was observed in 16 of 39 patients (20 of 64 renal units) ranging from grades 1 through 5. VCUG and ceVUS were concordant for detecting reflux in 10 of 39 patients (14 of 84 renal units) and excluding reflux in 23 of 39 patients (64 of 84 renal units) (Fig. 1). Using contrast enhanced voiding urosonography, 1 of 20 renal units had high-grade and 2 of 20 renal units had low-grade reflux that was not found on fluoroscopy. Using fluoroscopy, 1 of 20 renal units had high-grade and 2 of 20 renal units had low-grade reflux that had not been found on ceVUS. Two of 20 renal units were upgraded from low-grade on ceVUS to high-grade on fluoroscopy. This corresponds to a Cohen's kappa of 0.72 (confidence interval [CI] 0.54-0.91) or 'moderate.'

DISCUSSION

During our investigation, we noted that there was a technical learning curve related to poor contrast mixing and the need to titrate the concentration of Lumason. However, over the course of the study, we were able to correct the technical aspects. Ultimately, our results showed good correlation between VCUG and Lumason ceVUS and only slightly less correlation than published studies by experienced centers. Future studies with voiding should allow for improved urethral visualization.

CONCLUSION

While there is a considerable learning curve to the implementation of ceVUS for the diagnosis of pediatric VUR, these technical aspects can be corrected. Even a center previously naïve to contrast-enhanced ultrasound technology can, over a short period of time, demonstrate good correlation between VCUG and ceVUS in the diagnosis of VUR. Translation of ceVUS into clinical practice is an alternative to VCUG for diagnosis of reflux, is feasible, and can eliminate the radiation exposure associated with a VCUG.

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.

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

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

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.

A Low-Cost, Durable and Re-Usable Bladder Phantom: Teaching Intravesical Ultrasound Contrast Administration

Contrast-enhanced voiding urosonography (ceVUS) is a radiation-free and highly sensitive examination for detecting vesicoureteral reflux and imaging the urethra in children. This examination is performed with ultrasound and intravesical administration of a gas-filled microbubble US contrast agent. The U.S. Food and Drug Administration recently approved the use of a US contrast agent for ceVUS in children. Because of the growing interest among physicians and US technologists in using ceVUS in children, a urinary bladder phantom was developed to teach intravesical ultrasound contrast administration to perform ceVUS procedures. Described here are the preparation and utility of a low-cost, durable and re-usable phantom that simulates the administration, distribution and effects of different US parameters on US contrast agent appearance in the bladder during ceVUS in children.