Vesicoureteral reflux grading in contrast-enhanced voiding urosonography

Effects of Intrarenal Reflux on Renal Growth in Children With Grades III-V Primary Vesicoureteral Reflux

The phenomenon of intrarenal reflux (IRR) has been considered a crucial link between vesicoureteral reflux (VUR) and segmental scarring. We conducted a study on renal length in 104 children diagnosed with Grades III-V VUR, with or without IRR, using contrast-enhanced voiding urosonography (ceVUS). The patients were divided into two treatment groups: the conservative antibiotic prophylaxis (CAP) group and the operation group, which were further categorized into two subgroups: the IRR group and the non-IRR group. Our findings revealed an incidence rate of 35.96% (41/114) for IRR occurrence, with 43.42% (33/76) occurring in upper renal segments, 32.89% (25/76) in lower segments, and 23.68% (18/76) in middle segments. In the CAP group where the effects of IRR persisted, the renal growth observed was as follows: IRR group-0.19 ± 0.13 cm; non-IRR group-0.39 ± 0.23 cm; contralateral negative group-0.66 ± 0.35 cm; control group-0.46 ± 0 .25 cm respectively (P < .05). In the operation group, where the effects of IRR were eliminated, the renal growth for the IRR group, non-IRR group, contralateral negative group, and control group was 0.46 ± 0.22 cm, 0.54 ± 0.31 cm, 0.67 ± 0 .42 cm, and 0.36 ± 0.17 cm respectively (P < .005). In conclusion, the presence of IRR can impact renal growth in children diagnosed with Grades III-V primary VUR. Following surgical intervention, the IRR kidney does not exhibit catch-up growth; however, it demonstrates parallel growth alongside the unaffected kidney. Conversely, the non-IRR kidney experiences catch-up growth. Therefore, for children presenting with Grades III-V primary VUR combined with IRR, a more aggressive treatment approach such as surgery is recommended.

Value of contrast-enhanced sonography in the diagnosis of vesicoureteral reflux

BACKGROUND

 Contrast-enhanced ultrasound of the urinary tract and bladder (ceVUS) is an alternative examination method to micturition cysturethrography (MCU/VCUG) for suspected vesicoureteral reflux (VUR) that is increasing in practice. The purpose of this review is to present the current value of ceVUS in the diagnosis.

METHOD

 A systematic literature search was performed using the keywords "vesicoureteral reflux", "ceVUS", "VCUG" of the databases MEDLINE and Cochrane Library as well as a review of current German, European, and American guidelines on this topic. In addition, recommendations for action in clinical practice were developed.

CONCLUSION

 ceVUS is a quick-to-learn examination method that is equivalent to VCUG for the diagnosis of vesicoureteral reflux and should be used as the diagnostic method of first choice when available given the absence of radiation exposure.

KEY POINTS

  · Like VCUG, ceVUS is the diagnostic method of first choice in suspected vesicoureteral reflux and should be used preferentially given the absence of radiation exposure.. · Especially in comparison to the alternative VCUG, ceVUS is a quick-to-learn examination method.. · ceVUS can also be used to diagnose other pathologies of the lower urinary tract..

CITATION FORMAT

· Conen P, Thiemann J, Stredele R et al. Value of contrast-enhanced sonography in the diagnosis of vesicoureteral reflux. Fortschr Röntgenstr 2024; 196: 1022 - 1028.

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.

An innovative diagnostic procedure in children: videourodynamics with contrast-enhanced voiding urosonography

Contemporary videourodynamic (VUD) investigation combines voiding cystourethrography (VCUG) and urodynamics into one study, which allows simultaneous visualization of the urinary tract by ionizing radiation alongside the measurement of sensation, capacity, compliance, and detrusor pressure during bladder filling and voiding using one double lumen catheter. Today VUD is a benchmark for evaluating the lower urinary tract disorders in children because it evaluates urinary bladder and sphincter function and visualizes bladder morphology and vesicoureteral reflux (VUR) presence at the same time. Several previous studies of fluoroscopic videourodynamics issued concerns regarding radiation exposure. This technical report aims to describe a new modality of VUD in children by replacing fluoroscopic VCUG with contrast-enhanced voiding urosonography (ceVUS). ceVUS using second-generation contrast media and harmonic imaging is a radiation-free and highly sensitive imaging modality used to detect VUR in children. We simultaneously performed an infusion of ultrasound contrast through the double lumen urodynamic catheter during urodynamic evaluation. This article describes the advantages of this method compared with a conventional technique. In addition to being radiation-free, this procedure of advanced videourodynamics method can better detect vesicoureteral reflux and intrarenal reflux combined with urodynamic disorders associated with VUR.

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.

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.

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.

Sonography in Childhood and Adolescence for General Radiologists - More Possibilities Than Expected

Sonography is the most common imaging modality in childhood and adolescence. The rapid availability, absence of X-rays, bedside applicability, e. g., in intensive care units, the lack of need for sedation, and last but not least the very good ultrasound conditions in the vast majority of cases are the main advantages of sonography. Due to the spectrum of patients, from premature infants to adolescents, a great variety of questions arise for the examiner. This requires knowledge of the various disease patterns in the different age groups. Proper handling of the young patients as well as their parents is essential in order to make the examination conditions as optimal as possible. Due to the smaller body size compared to adults, sonographic examinations of the abdomen and thorax in children and adolescents are usually possible with very good image quality. In the majority of cases, a definitive diagnosis is made by sonography without additional cross-sectional imaging, which is more common in adults. Due to the acoustic windows provided by the still open fontanelles, excellent image quality of the central nervous system is usually possible in the first year of life. In most cases, complex MRI examinations are not necessary. Due to the partly still missing ossification of the bony structures, further acoustic windows are available, which allow an examination of, e. g., the spinal canal. Ultrasound also plays a major role in the examination of soft tissues and the musculoskeletal system in childhood and adolescence, not only in hip ultrasound. The aim of this article is to show this very broad spectrum for colleagues working predominantly in adult radiology, to highlight some representative examples and to present the respective clinical features in childhood and adolescence. KEY POINTS::   · Ultrasound is the most important initial imaging modality in children and adolescents.. · Often, no further cross-sectional imaging is necessary.. · The most important area of application is the abdomen and pelvis.. · Furthermore, there are additional special applications such as CNS in neonates and infants, thorax, musculoskeletal system.. CITATION FORMAT: · Schaal MC, Moritz JD, Mentzel H et al. Sonography in Childhood and Adolescence for General Radiologists - More Possibilities Than Expected.... Fortschr Röntgenstr 2021; DOI: 10.1055/a-1681-2136.

Contrast-enhanced voiding ultrasonography to detect intrarenal reflux in children: comparison with 99mTc-DMSA renal scans

Purpose

This study evaluated the diagnostic performance of contrast-enhanced voiding ultrasonography (CeVUS) for detecting intrarenal reflux (IRR) and the correlation between CeVUS-detected IRR sites and photon defect sites in acute ^99mTc-dimercaptosuccinic acid (DMSA) renal scans in pediatric patients.

Methods

Fifty-four kidneys from 27 patients (20 males and seven females; mean age, 5.6±4.1 months) who underwent CeVUS and acute DMSA renal scans for recurrent urinary tract infection (UTIs) or pyelonephritis were included. Pediatric experts compared the results of CeVUS with acute DMSA renal scans.

Results

Thirteen renal units (13/54, 24.1%) in 10 patients (nine males and one female; mean age, 6.3±3.7 months; age range, 0 to 13 months) showed vesicoureteral reflux and eight renal units (8/54, 14.8%) demonstrated IRR on CeVUS. Ten renal units in eight patients (six males and two females; mean age, 6.9±1.4 months; age range, 2 to 13 months) showed 19 photon defects on acute DMSA renal scans. Fifty-two renal units (96.3%) showed concordant results, and two renal units (3.7%) showed discordant results between CeVUS and acute DMSA renal scans. IRR accounted for 15/19 (78.9%) photon defects in eight renal units of seven patients using CeVUS. In a per-renal-unit analysis, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CeVUS were 80%, 100%, 100%, 95.7%, and 96.3%, respectively.

Conclusion

CeVUS showed good performance in detecting IRR, and the IRR sites detected by CeVUS closely correlated with photon defect sites in acute DMSA scans. CeVUS may play an important role in managing patients with recurrent UTIs or pyelonephritis with reduced radiation exposure.

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.

Contrast -Enhanced Ultrasound: State of the Art in North America

The Society of Radiologists in Ultrasound convened a panel of specialists in contrast-enhanced ultrasound (CEUS) to produce a white paper on noncardiac CEUS in North America. The panel met in Chicago, Illinois, on October 24 and 25, 2017. The recommendations are based on analysis of current literature and common practice strategies and are thought to represent a reasonable approach to introduce the advantages of this safe and noninvasive technique for the benefit of our patients. Characterization of liver nodules, and pediatric vascular and intravesicular applications comprise the approved indications for CEUS in the United States. They, along with the very successful off-label use of CEUS for the kidney, are included in this publication.Other off-label uses are presented with emphasis on their value and literature support in the online version.

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.

Contrast-enhanced voiding urosonography in the diagnosis of intrarenal reflux

PURPOSE

Although contrast-enhanced urosonography (ceVUS) has shown capable diagnostic accuracy for the diagnosis of vesicoureteral reflux (VUR) in children, the ability of ceVUS to detect intrarenal reflux (IRR) is considered limited. The purpose of our study is to assess the ability of ceVUS to detect IRR as well as its association with age, gender, and the grade of VUR.

METHODS

This study included 5153 children who were referred to our clinic for ceVUS. All children underwent sonographic examinations, which were performed on a LOGIQ S8 machine equipped with dedicated software for contrast-enhanced studies with harmonic imaging. Standard ultrasound of the urinary tract was followed by bladder catheterisation and instillation of physiological normal saline and the US contrast medium (SonoVue^®, Bracco).

RESULTS

VUR was diagnosed by ceVUS in 1959 out of 5153 children (38%), of whom IRR was found in 233 of 1959 children (11.9%). A total of 285 ureteral units showing IRR were found. High grades of VUR (IV + V) with IRR were found in a total of 235 of 285 (82.81%) renal units. Bilateral IRR was found in 53 patients, usually with a high-grade VUR on both sides. Most children had VUR grade IV, predominantly those < 12 months. The younger the child, the higher the likelihood of higher-grade VUR (p = 0.02).

CONCLUSION

ceVUS, combined with harmonic imaging and second-generation ultrasound contrast media, enabled IRR detection in almost 12% of our patients with VUR. IRR is most commonly found in children under 1 year of age with VUR grades IV and V.

Contrast-enhanced voiding urosonography for the diagnosis of vesicoureteral reflux and intrarenal reflux: a comparison of diagnostic performance with fluoroscopic voiding cystourethrography

Purpose

This study evaluated the diagnostic performance of contrast-enhanced voiding urosonography (ce-VUS) using a second-generation ultrasound contrast agent for the diagnosis of vesicoureteral reflux (VUR) and intrarenal reflux (IRR), and compared it with that of standard fluoroscopic voiding cystourethrography (VCUG).

Methods

Thirty-two consecutive children from April to October 2019 were included in this study. ce-VUS and VCUG were performed simultaneously by two operators with intravesical infusion of a mixture of ultrasound contrast medium, iodinated contrast medium and water. Two pediatric radiologists independently reviewed the ce-VUS and VCUG images and reported the presence and degree of VUR (grades I-V), and the presence and type of IRR.

Results

Twenty-seven of 63 urinary systems showed VUR. Interobserver agreement for VUR grading was very good for both examinations (κ=0.87; 95% confidence interval [CI], 0.82 to 0.92 for ce-VUS and κ=0.92; 95% CI, 0.87 to 0.96 for VCUG). The detection rate of VUR showed no significant difference between the two examinations (P=0.370). Four cases of VUR were missed on ce-VUS, while one case of VUR was missed on VCUG. All four false-negative cases on ce-VUS were grade 1 VUR. The two examinations showed very good agreement regarding VUR grading (κ =0.89; 95% CI, 0.81 to 0.96). IRR was more frequently detected with ce-VUS than with VCUG (10 cases with ce-VUS vs. 3 cases with VCUG, P=0.016).

Conclusion

ce-VUS showed very good agreement with VCUG for detecting grade 2 VUR and above, while grade 1 VUR was sometimes missed with ce-VUS. IRR was more frequently detected with ce-VUS than with VCUG.

Voiding urosonography and voiding cystourethrography in primary vesicoureteral reflux associated with mild prenatal hydronephrosis: a comparative study

BACKGROUND

Contrast-enhanced harmonic voiding urosonography has been introduced as a sensitive, radiation-free imaging method for the diagnosis of vesicoureteric reflux.

OBJECTIVE

To evaluate the occurrence/severity of vesicoureteric reflux in infants with mild prenatal hydronephrosis comparing voiding cystourethrography and voiding urosonography.

MATERIALS AND METHODS

Sixty infants with prenatal hydronephrosis were studied (anteriοposterior pelvic diameter 5-9 mm on ultrasound [US] at gestational weeks 21-30). Postnatal US was performed within the first month of life, as well as voiding cystourethrography and contrast-enhanced voiding urosonography at 1.5-2.5 months at the same session.

RESULTS

Vesicoureteric reflux was diagnosed on at least one modality in 19/60 (32%) infants, and more often on contrast-enhanced voiding urosonography (18/60, 30%) than on voiding cystourethrography (8/60, 13%), P=0.046. Among girls, reflux was more often seen on contrast-enhanced voiding urosonography (6/16, 38%) than on voiding cystourethrography (1/16, 6%), P=0.03. Vesicoureteric reflux missed by voiding cystourethrography was more severe (Grades I, II and III in one, nine and four kidney-ureter-units, respectively), compared with a single case missed by contrast-enhanced voiding urosonography (Grade I in one kidney-ureter-unit).

CONCLUSION

In the absence of a reference standard, our results imply that voiding cystourethrography might underdiagnose reflux, and/or contrast-enhanced voiding urosonography may overdiagnose reflux.

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.

3D/4D contrast-enhanced urosonography (ceVUS) in children - is it superior to the 2D technique?

Background: By now, two-dimensional contrast-enhanced voiding urosonography (ceVUS) has become a well-established method for the diagnosis and treatment monitoring of vesicoureteral reflux in children, particularly after the recent approval for this application in children in the USA and in Europe. The introduction of three-dimensional static (3D) and real-time (4D) techniques with ultrasound contrast agents opens up new diagnostic opportunities for this imaging modality. Objective: To analyze whether 3D and 4D ceVUS is a superior technique compared to standard 2D ceVUS in diagnosing vesicoureteral reflux in children. Material and methods: The study included 150 patients (mean age 3.7 years) who underwent 2D and 3D/4D ceVUS for the diagnosis and grading of vesicoureteral reflux. Results: 2D ceVUS and 3D/4D ceVUS diagnosed the same number of vesicoureteral refluxes, however, there was a statistically significant difference in grading between the two methods. Performing 3D/4D ceVUS resulted in changing the initial grade compared to 2D ceVUS in 19 out of 107 refluxing units (17.76%) diagnosed. The 4D technique enabled a more conspicuous visualization of vesicoureteral reflux than the 3D technique. Conclusions: 2D ceVUS and 3D/4D ceVUS diagnosed the same number of vesicoureteral refluxes, however, there was a statistically significant difference in grading between the two methods. Thus 3D/4D ceVUS appears at least a valid, if not even a more conspicuous technique compared to 2D ceVUS.

Applications of contrast-enhanced ultrasound in the pediatric abdomen

Contrast-enhanced ultrasound (CEUS) is a radiation-free, safe, and in specific clinical settings, highly sensitive imaging modality. Over the recent decades, there is cumulating experience and a large volume of published safety and efficacy data on pediatric CEUS applications. Many of these applications have been directly translated from adults, while others are unique to the pediatric population. The most frequently reported intravenous abdominal applications of CEUS in children are the characterization of focal liver lesions, monitoring of solid abdominal tumor response to treatment, and the evaluation of intra-abdominal parenchymal injuries in selected cases of blunt abdominal trauma. The intravesical CEUS application, namely contrast-enhanced voiding urosonography (ceVUS), is a well-established, pediatric-specific imaging technique entailing the intravesical administration of ultrasound contrast agents for detection and grading of vesicoureteral reflux. In Europe, all pediatric CEUS applications remain off-label. In 2016, the United States Food and Drug Administration (FDA) approved the most commonly used worldwide second-generation ultrasound contrast SonoVue®/Lumason® for pediatric liver and intravesical applications, giving new impetus to pediatric CEUS worldwide.

Contrast-enhanced Voiding Urosonography for Vesicoureteral Reflux Diagnosis in Children

Contrast-enhanced voiding urosonography (ceVUS) is a dynamic imaging technique that makes it possible to study the structure of the urinary tract after the administration of intravesical contrast material. Initially, ceVUS was indicated mainly to study vesicoureteral reflux (VUR); however, since the ability of ceVUS to depict the structure of the urethra was demonstrated in both sexes, ceVUS is now indicated for examination of the entire urinary tract. The main benefit of ceVUS is that it does not use ionizing radiation. In recent years, fundamental changes have occurred in the understanding of VUR. The lessening effect of VUR and the low rate of occurrence of urethral pathologic conditions have given rise to changes in the indications for tests for these conditions. In addition to being able to help confirm a diagnosis of VUR, the ceVUS technique can be used to depict obstructive and nonobstructive urethral pathologic conditions, as well as normal variants, on high-quality images. Furthermore, ceVUS enables real-time assessment of voiding function. For these reasons, ceVUS should be not only an alternative to voiding cystourethrography, but also the technique of choice for the study of the entire urinary tract in pediatric patients. Online supplemental material is available for this article. ^©RSNA, 2017.

Comparison of contrast-enhanced voiding urosonography with voiding cystourethrography in pediatric vesicoureteral reflux

OBJECTIVE

Voiding cystourethrography (VCUG) has been considered as the gold standard technique for the diagnosis of vesicoureteral reflux (VUR). But, it requires fluoroscopic guidance which expose children to radiation. Voiding urosonography (VUS) is technically analogous to VCUG and has the major advantage of zero radiation exposure. This study aims to determine the efficacy of contrast enhanced-VUS (ce-VUS) with respect to VCUG in diagnosing VUR.

MATERIAL AND METHODS

This study involves 30 children over a period of 3 years. All patients underwent a VCUG followed by the ce-VUS on the same day. All VUS studies were done by the same sonologist in the sonography department. The images were recorded and reviewed by the same sonologist before reporting.

RESULTS

The median age of the patients was 51.53 months. There were 21 males and 9 females. On VCUG, 16 patients had no reflux, and 14 patients had reflux. On ce-VUS, 14 patients had no VUR, and 16 patients had VUR. Of the total 58 kidney-ureter units (KUUs), VUR was detected in 17 KUUs on VCUG and in 21 KUUs on ce-VUS. Thus, ce-VUS detected 4 refluxing units that were not seen on VCUG. In right KUUs, ce-VUS detected VUR in 3 units where no reflux was found in VCUG. In the 28 left KUUs, 25 units on ce-VUS showed concordance with the grade of VUR as detected by VCUG; 3 were discordant. Two units on ce-VUS showed a VUR one grade higher than the corresponding grade on VCUG and in one unit it was one grade lower. Thus, in total, ce-VUS picked up 4 cases which were missed by VCUG.

CONCLUSION

ce-VUS is a good imaging modality when compared to voiding cystourethrography to assess pediatric vesicoureteral reflux, in view of its superior diagnostic performance, feasibility and radiation safety for children.

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

BACKGROUND

Contrast-enhanced voiding urosonography (ceVUS) is widely used outside the United States to diagnose vesicoureteral reflux (VUR) in children and is highly sensitive while avoiding exposure to ionizing radiation. At the onset of this study, two ultrasound (US) contrast agents were available in the United States. Pediatric safety data for intravenous administration was published for one, Optison™.

OBJECTIVE

This study aimed to evaluate the diagnostic performance and safety of ceVUS using Optison™ and compare its diagnostic efficacy with voiding cystourethrogram (VCUG) for VUR detection and grading in children.

MATERIALS AND METHODS

The United States Food and Drug Administration and institutional Investigational New Drug authorizations were obtained to conduct a prospective comparative study of ceVUS with Optison™ and VCUG. CeVUS was performed with intravesical administration of 0.2% Optison™/normal saline solution. A standard VCUG followed. Safety assessment included physical examination, and heart rate, pulse oximetry and adverse reactions monitoring before, during and immediately after the examinations. A follow-up questionnaire was completed by telephone 48-h after the studies.

RESULTS

Sixty-two pelviureteric units were studied in 30 patients with a mean age of 3.5 years (range: 0.1-17 years) including 21 girls and 9 boys. No severe adverse events occurred. All patients had normal heart rate and blood oxygenation saturation prior to, during and after the studies. At the 48-h follow-up, one patient (3.3%) reported transient dysuria. Taking the VCUG as the reference standard, ceVUS had a sensitivity of 91.7% (95%; confidence interval [CI]: 61.5%-99.8%) and specificity of 98% (95%; CI: 89.4%-99.9%). The concordance between ceVUS and VCUG for VUR detection and grading was 84.3% and 81.8%, respectively. VUR grades were discrepant in 4/11 refluxing pelviureteric units, with VCUG upgrading VUR in 2.

CONCLUSION

Detection of VUR with Optison™ ceVUS was comparable to VCUG without exposure to ionizing radiation. CeVUS with Optison™ is a well-tolerated diagnostic procedure with a favorable safety profile.

Standardization of pediatric uroradiological terms: a multidisciplinary European glossary

To promote the standardization of nephro-uroradiological terms used in children, the European Society of Paediatric Radiology uroradiology taskforce wrote a detailed glossary. This work has been subsequently submitted to European experts in pediatric urology and nephrology for discussion and acceptance to improve the quality of radiological reports and communication between different clinicians involved in pediatric urology and nephrology.

Standardization of pediatric uroradiological terms: A multidisciplinary European glossary

To promote the standardization of nephro-uroradiological terms used in children, the European Society of Pediatric Radiology uroradiology taskforce wrote a detailed glossary. This work has been subsequently submitted to European experts in pediatric urology and nephrology for discussion and acceptance to improve the quality of radiological reports and communication among different clinicians involved in pediatric urology and nephrology.

Voiding Urosonography with Second-Generation Ultrasound Contrast Agent for Diagnosis of Vesicoureteric Reflux: First Local Pilot Study

BACKGROUND:

Vesicoureteric reflux (VUR) is an important association of paediatric urinary tract infection (UTI) found in 30-50% of all children presenting with first UTI. Contrast-enhanced voiding ultrasonography (ceVUS) has become an important radiation-free method for VUR detection in children. Its sensitivity in detecting VUR has greatly improved due to the development of the contrast-specific ultrasound techniques and the introduction of the second-generation ultrasound contrast agent, superseding the diagnostic accuracy of standard radiological procedures.

AIM:

This article aimed to summarise the current literature and discuss the first local pilot study performed in our institution on detection of vesicoureteric reflux by contrast-enhanced voiding ultrasonography with second- generation agent (SonoVue, Bracco, Italy).

MATERIAL AND METHODS:

Retrospective review of the first 31 ceVUS (24 girls, 7 boys) was presented. Age range was 2 months to 18 years (mean = 6.4 ± 4.9).

RESULTS:

All examinations were well tolerated without any adverse incident. VUR was shown in 20 (64.5%) children in 32/62 (51.6) nephroureteral units (NUUs). In 18 NUUs, VUR was grade II/V, in 11 Grade III/V and in 3 grade IV/V, respectively. Urethra was shown in 19/31 children and in all boys, without pathological finding. In two girls spinning top urethra has been detected. Subsequent urodynamic studies revealed functional bladder problem in both.

CONCLUSIONS:

Contrast-enhanced voiding urosonography using intravesical second generation ultrasound contrast agent could be recommend as a valid alternative diagnostic modality for detecting vesicoureteral reflux and evaluation of the distal urinary tract in children, based on its radiation-free, highly efficacious, reliable, and safe characteristics.

Comparison of voiding cystourethrography and urosonography with second-generation contrast agents in simultaneous prospective study

Background

The invasiveness and exposure to radiation in voiding cystourethrography led to the introduction of alternative methods of diagnosis of vesicoureteral reflux, including contrast enhanced voiding urosonography. While there is a limited number of studies comparing these methods using new generation ultrasound contrast agents, none of them compared both methods simultaneously. This study is aimed at assessing agreement between contrast enhanced voiding urosonography with second-generation ultrasound contrast agents and voiding cystourethrography.

Methods

From April 2013 to May 2014, 83 children (37 female and 46 male), mean age 3.5 years, age range from 1 month to 17.5 years, underwent prospective simultaneous assessment by contrast enhanced voiding urosonography and voiding cystourethrography, with a total of 166 uretero-renal units evaluated.

Results

The sensitivity of voiding cystourethrography and contrast enhanced voiding urosonography were comparable, amounting to 88%, however, neither reached 100% for the entire studied population. The negative predictive value of voiding urosonography and voiding cystourethrography was 97%, and there was no difference between both methods.

Conclusion

Voiding cystourethrography and contrast enhanced voiding urosonography are comparable methods in diagnosis of vesicoureteral reflux, and can be performed alternatively. However, some limitations of contrast enhanced voiding urosonography must be remembered.

Premature Destruction of Microbubbles during Voiding Urosonography in Children and Possible Underlying Mechanisms: Post Hoc Analysis from the Prospective Study

The aim of this study is to describe premature microbubbles destruction with contrast-enhanced voiding urosonography (ce-VUS) in children using 2nd-generation ultrasound contrast agents (UCA) and to hypothesize about the reason. 141 children (61 females and 80 males) were included in the study, with mean age of 3.3 years (range 4 weeks–16.0 years), who underwent ce-VUS examination between 2011 and 2014. Premature destruction of the microbubbles in the urinary bladder during ce-VUS was observed in 11 children (7.8%). In all these cases the voiding phase of ce-VUS examination could not be performed because of destroyed UCA microbubbles. This was noted in anxious, crying infants and children with restricted voiding. The premature destruction of ultrasound contrast agent during ce-VUS is an underreported, important limitation of ce-VUS, which prevents evaluation of the voiding phase and the establishment of vesicoureteric reflux (VUR). This was particularly noted in crying infants and children.

Two-dimensional (2D), three-dimensional static (3D) and real-time (4D) contrast enhanced voiding urosonography (ceVUS) versus voiding cystourethrography (VCUG) in children with vesicoureteral reflux

BACKGROUND

Two-dimensional (2DUS) contrast enhanced voiding urosonography has been used in the diagnosis and treatment monitoring of the vesicoureteral reflux in children for over 15 years. The opportunity of performing this examination with the use of three-dimensional static (3DUS) and real-time (4DUS) techniques opens up new diagnostic horizons.

OBJECTIVE

To analyze if 3DUS/4DUS bring additional information leading to an increased detection rate or change in the grading of reflux compared to 2DUS and voiding cystouretrography.

MATERIAL AND METHODS

We evaluated 69 patients (mean 4.1 years) who underwent 2DUS/3DUS/4DUS contrast enhanced voiding urosonography (ceVUS) and voiding cystourethrography (VCUG) for the diagnosis and grading of vesicoureteral reflux.

RESULTS

2DUS and 3DUS/4DUS urosonography diagnosed 10 more refluxes (7.25%) than cystourethrography and in 3 refluxes (2.17%) detected a higher grade. In 9 refluxes (6.52%) 3DUS/4DUS urosonography and cystourethrography diagnosed a higher grade than 2DUS. There was a statistically significant difference between cystourethrography and 3DUS/4DUS urosonography when the number of detected refluxes and differences in grading were compared. 4DUS enabled a better visualization of reflux than 3DUS.

CONCLUSIONS

3DUS/4DUS techniques bring additional information leading to a change in reflux grading compared to 2DUS and a detect higher number of refluxes compared to cystourethrography.

Voiding urosonography: Contrast-enhanced ultrasound cystography to diagnose vesico-ureteric reflux: A pilot study

We report two children with hydronephrosis, in whom we have utilized voiding urosonography (VUS) in the evaluation of vesico-ureteric reflux. With wider availability of ultrasound contrast agents and high-end ultrasound machines, VUS is likely to become a popular tool to diagnose or exclude VUR.

Voiding urosonography with second-generation ultrasound contrast versus micturating cystourethrography in the diagnosis of vesicoureteric reflux

Vesicoureteric reflux has been associated with paediatric urinary tract infection. Fluoroscopic micturating cystourethrography (MCU) has been the gold standard of diagnostic test for decades; however, it has been criticized owing to its lower detection rate and radiation dose to children. Therefore, new radiation-free reflux imaging modalities have been developed, in which ultrasound-based contrast-enhanced voiding urosonography (ceVUS) is a good example. However, ultrasonography has been considered as an operator-dependent examination. Therefore, our study aimed to examine the inter-observer agreement of this sonographic technique, which has not been evaluated before. Moreover, the second-generation ultrasound contrast SonoVue has been recently marketed, and the data on its efficacy on intravesical use in ceVUS is relatively scarce. Thus, we also aimed to investigate the diagnostic performance and safety profile of SonoVue-enhanced VUS in the diagnosis of vesicoureteric reflux. Our prospective comparative study compared the diagnostic performance of ceVUS with MCU in young children presenting with first episode of urinary tract infection. We performed sequential ceVUS and MCU examinations in 31 patients (62 pelvi-ureter units). Perfect inter-observer agreement (Cohen’s kappa statistics = 1.0, p < 0.001) was achieved in ceVUS, suggesting its good reliability in reflux detection and grading. Using MCU as reference, ceVUS had 100 % sensitivity and 84 % specificity and carried higher reflux detection rate than MCU (p < 0.001). There was no complication encountered. Conclusion: Voiding urosonography is a reliable, sensitive, safe and radiation-free modality in the investigation of vesicoureteric reflux in children. It should be incorporated in the diagnostic algorithm in paediatric urinary tract infection.

Safety of ultrasound contrast agents in the pediatric oncologic population: a single-institution experience

OBJECTIVE

Little information is available regarding the safety of ultrasound contrast agents in children. The purpose of this article was to assess the safety profile of the i.v. administration of ultrasound contrast agents in the pediatric oncology population.

MATERIALS AND METHODS

Patients with pediatric solid malignancies who were enrolled on institutional clinical trials conducted between June 2003 and January 2013 and who met our institutional screening criteria for contrast-enhanced ultrasound (CEUS) were eligible. After providing informed consent or assent for CEUS, subjects received i.v. bolus injections of one of two contrast agents for imaging of the primary tumor or a metastatic target lesion. Hemodynamic parameters, including heart rate, cardiac rhythm, and oxygen saturation, were monitored immediately before and for 30 minutes after the administration of the contrast agent. Interviews with the subject or a guardian were conducted by the principal investigator or a radiologist coinvestigator before and after the examination to assess for any adverse effects.

RESULTS

Thirty-four subjects (21 male and 13 female) ranging in age from 8 months to 20.7 years (median, 8.7 years) underwent 134 CEUS. No detrimental change in hemodynamic status occurred in any subject. Three subjects (3/134, 2.2%) reported mild transient side effects on one occasion each, two (2/134, 1.5%) had taste alteration, and one (1/134, 0.8%) reported mild transient tinnitus and lightheadedness. These reactions did not recur in these subjects on subsequent CEUS examinations.

CONCLUSION

The i.v. administration of ultrasound contrast agents is safe and well tolerated in the pediatric oncology population. Further studies in children are needed to confirm our findings.

Contrast-enhanced voiding urosonography with intravesical administration of a second-generation ultrasound contrast agent for diagnosis of vesicoureteral reflux: prospective evaluation of contrast safety in 1,010 children

BACKGROUND AND OBJECTIVE

To evaluate the safety of intravesical administration of a second-generation ultrasound (US) contrast agent for the diagnosis of vesicoureteral reflux in children.

MATERIALS AND METHODS

One thousand and ten children (563 girls, 447 boys; mean age: 2.9 years, range: 15 days-17.6 years) with 2,043 pelvi-ureter-units underwent contrast-enhanced voiding urosonography (ce-VUS) to rule out vesicoureteral reflux. A second-generation US contrast agent (SonoVue®, Bracco, Milan) was administered intravesically through transurethral bladder catheterization at a dose of 0.5 ml/bladder filling. Possible adverse events were monitored during the examination and followed up for 7 days after ce-VUS by phone calls. Urine analysis and culture were performed 3-5 days before ce-VUS in all children and 24-48 h in any patient who reported with adverse events.

RESULTS

No case of serious adverse event was recorded. Minor events were reported in 37 children (3.66% of the study population). These included dysuria (n = 26, 2.57%), urinary retention (n = 2, 0.2%), abdominal pain (n = 2, 0.2%), anxiety (n = 1, 0.1%) and crying (n = 1, 0.1%) during micturition, blood and mucous discharge (n = 1, 0.1%), increased frequency of micturition (n = 1, 0.1%), vomiting (n = 1, 0.1%), perineal irritation (n = 1, 0.1%), and an episode of urinary tract infection 10 days after ce-VUS (n = 1, 0.1%). Of these adverse events, 91.9% were subacute in onset and 8.1% were delayed. All events were self-limited and none required hospitalization.

CONCLUSION

There were no serious adverse events. Only a few minor events were reported, most likely due to the catheterization process. Thus, ce-VUS with intravesical administration of the second-generation US contrast agent (SonoVue®) for vesicoureteral reflux detection or exclusion had a favorable safety profile in our study group.

Demonstration of an occult biliary-arterial fistula using percutaneous contrast-enhanced ultrasound cholangiography in a transplanted liver

We present a case of a biliary-arterial communication as a consequence of the placement of an internal-external biliary drainage catheter in a liver transplant patient diagnosed on contrast-enhanced ultrasound using a novel application by injecting microbubble contrast into the catheter tube. We postulate that this method may be sensitive in identifying occult communications between the biliary tree and the vascular compartment when a catheter drain is positioned, and there is hemobilia or unexplained sepsis.

[Ultrasound examination in childhood: new perspectives]

Everyday use of the modern imaging techniques such as CT, MRI, isotope, PET/CT decreased the reputation and importance of ultrasound. In some cases, ultrasound is only the first exploratory imaging method. Using the latest multi-slice CT, imaging can be performed in seconds, which led to a dramatic increase in the number of CT exams. However, this also means a significant radiation exposure to children, while US still harmless in this regard. In addition, significant progress has been made in ultrasound technology in recent years, which led an improvement in image quality. Children are ideal subjects for US examination as they usually have smaller weight with less body fat. Thus, ultrasound examination is easy to perform with a high frequency transducer resulting in much more detailed and higher resolution than in adults. With adequate equipment and experienced examiner in pediatric radiology, almost all parts of the body can be examined, making this technique as the first (sometimes together with X-ray) and, in most cases, the ultimate imaging exam for the diagnosis. This article will discuss the possibilities where ultrasound performed with a modern device is sufficient for an accurate diagnosis.

Intraoperative contrast-enhanced urosonography during endoscopic treatment of vesicoureteral reflux in children

BACKGROUND

There are many controversies surrounding the effectiveness of endoscopic treatment of vesicouretheral reflux (VUR) in children, thus it is of highest priority to analyze factors influencing the outcome of therapy and to search for new methods that would increase the success rate and reduce the number of reinjections.

OBJECTIVE

The aim of the study was to analyze whether intraoperative contrast-enhanced urosonography (ce-US) may increase the effectiveness of endoscopic anti-reflux therapy.

MATERIALS AND METHODS

Intraoperative contrast-enhanced urosonography (ce-US) with SonoVue® was performed in 17 patients (25 ureteral units) undergoing endoscopic treatment of VUR. Ce-US was performed in the operating room before the procedure and after injection of the bulking material. When VUR persisted, the operator repeated the injection, which was followed by ce-US. The results were compared with those obtained from a control group (15 patients; 22 ureteral units).

RESULTS

A repeat injection during a single endoscopic treatment was required in 24% of cases. The overall success rate confirmed at 6-12 months' follow-ups was 84%. The success rate was significantly higher in comparison to the control group (success: 64%).

CONCLUSION

Intraoperative ce-US performed during endoscopic treatment of VUR enables immediate monitoring of outcome and provides the opportunity for repeat injection during the same procedure, thus increasing the efficacy of the procedure and reducing the number of reinjections.

2D/3D/4D contrast-enhanced voiding urosonography in the diagnosis and monitoring of treatment of vesicoureteral reflux in children - can it replace voiding cystourethrography?

Introduction

Vesicoureteral reflux appears in 20–50% of pediatric patients with recurrent urinary tract infections. The most common method of diagnosing this disease is voiding cystourethrography. However, contemporary pediatric radiology does not favor this method due to exposure to X-radiation.

Aim

The aim of this study was to assess the usefulness of 2D/3D/4D contrast-enhanced voiding urosonography in the diagnosis and treatment monitoring of vesicoureteral reflux in children and the possibility of using contrast-enhanced voiding urosonography to replace voiding cystourethrography.

Material and methods

Voiding cystourethrography and contrast-enhanced voiding urosonography were conducted in 80 pediatric patients in order to assess sensitivity, specificity, positive and negative predictive values as well as the number of vesicoureteral refluxes detected by each of the two methods. The second stage of the study involved performing voiding urosonography in an extended protocol in 58 children in order to determine the usefulness of three-dimensional (3D/4D) examinations in the assessment of vesicoureteral reflux and the ability to assess the urethra.

Results

The concordance between the two methods was 86.95%. The sensitivity of voiding urosonography was 84.51%, specificity – 90.99%, positive predictive value – 85.71% and negative predictive value – 90.17%. A 3D/4D assessment of the urinary bladder and transperineal 2D morphological assessment of the urethra were possible in all patients (100%). Assessment of the urethra during micturition with the use of 2D/3D/4D techniques was possible in all patients in whom voiding was elicited (95.83%), and 3D/4D assessment of vesicoureteral reflux was possible in all patients with reflux (100%). Although the application of 3D/4D techniques allowed accurate specification of the grade of reflux in all cases (100%), it appeared particularly useful in differentiating between grades II and III (70.97%).

Conclusions

Contrast-enhanced voiding urosonography allows the diagnosis and monitoring of treatment of vesicoureteral reflux in pediatric patients as well as assessment of the urethra in both girls and boys. The method is characterized by high sensitivity and specificity. Moreover, it is safe, relatively inexpensive and can replace voiding cystourethrography.

Safety of contrast-enhanced ultrasound in children for non-cardiac applications: a review by the Society for Pediatric Radiology (SPR) and the International Contrast Ultrasound Society (ICUS)

The practice of contrast-enhanced ultrasound in children is in the setting of off-label use or research. The widespread practice of pediatric contrast-enhanced US is primarily in Europe. There is ongoing effort by the Society for Pediatric Radiology (SPR) and International Contrast Ultrasound Society (ICUS) to push for pediatric contrast-enhanced US in the United States. With this in mind, the main objective of this review is to describe the status of US contrast agent safety in non-cardiac applications in children. The five published studies using pediatric intravenous contrast-enhanced US comprise 110 children. There is no mention of adverse events in these studies. From a European survey 948 children can be added. In that survey six minor adverse events were reported in five children. The intravesical administration of US contrast agents for diagnosis of vesicoureteric reflux entails the use of a bladder catheter. Fifteen studies encompassing 2,951 children have evaluated the safety of intravesical US contrast agents in children. A European survey adds 4,131 children to this group. No adverse events could be attributed to the contrast agent. They were most likely related to the bladder catheterization. The existing data on US contrast agent safety in children are encouraging in promoting the widespread use of contrast-enhanced US.

Application of a second-generation US contrast agent in infants and children--a European questionnaire-based survey

BACKGROUND

No US contrast agent (US-CA) is currently licensed for use in children.

OBJECTIVE

To survey the off-label use in children of a second-generation US-CA.

MATERIALS AND METHODS

Questionnaires were e-mailed to European paediatric radiologists, who were asked about their experience with the second-generation US-CA Sonovue® (Bracco, Milan, Italy). Number of examinations per indication and adverse effects were recorded. Examinations were categorised by intravenous or intracavitary use of US-CA.

RESULTS

Out of 146 respondents, 88 stated that they did not perform contrast-enhanced US in children, but 36 of these (44%) would appreciate paediatric approval. Forty-five centres reported 5,079 examinations in children (age mean: 2.9 years; range: birth-18 years, M/F: 1/ 2.8). The majority (4,131 [81%] in 29 centres) were intravesical applications. The minority (948 [19%] in 30 centres) were intravenous applications. No adverse effects had been recorded from intravesical use. Six minor adverse effects (skin reaction, unusual taste, hyperventilation) had been recorded after five intravenous studies (0.52%).

CONCLUSION

Responses suggest a favourable safety profile of this second-generation US-CA in children. It also demonstrates a demand for such US-CA from paediatric radiologists.

[Serial voiding urosonography: a safe technique for the study of the entire urinary tract in children]

For more than a decade, serial voiding urosonography has been one of the imaging modalities used to detect vesicoureteral reflux in children and it is now also used to study the urethra. The main advantage of this technique is it does not irradiate. Given the important recognition of serial voiding urosonography by the European Society of Pediatric Radiology at the last congress in May 2011, we think it is useful to describe how to carry out this technique successfully. In this update on serial voiding urosonography, we describe the indications, the entire procedure, and the different characteristics of this technique, which we understand will soon become the technique of choice for screening for vesicoureteral reflux as well as for urethral pathology in children.

Voiding urosonography including urethrosonography: high-quality examinations with an optimised procedure using a second-generation US contrast agent

BACKGROUND

Voiding urosonography (VUS) is established as a technique for detecting vesicoureteral reflux in children.

OBJECTIVE

To evaluate the quality of images of the entire urinary tract when using a second-generation US contrast agent and a modified VUS technique.

MATERIALS AND METHODS

We evaluated 307 VUS examinations performed using SonoVue® in 591 pelvi-ureter units in 295 children of mean age, 27.1 (S.D., 42.5) months, with 154 (50.2%) of the examinations performed in boys; 58 children also underwent VUS using Levovist®. Three criteria were used for quality assessment of the bladder image: (1) progressive incorporation of contrast material in the bladder, (2) homogeneous bladder-filling to maximum capacity, and (3) visualisation of the posterior bladder wall.

RESULTS

Criterion 1 was fulfilled in 305 (99.3%), criterion 2 in 304 (99%) and criterion 3 in 304 (99%) studies. In children who underwent VUS with both contrast agents, the concordance between the two techniques was moderate for findings in the bladder (Cohen K = 0.487; P < 0001) and perfect for findings in the male urethra.

CONCLUSION

By a modified technique we obtained high-quality images of the bladder with the second-generation contrast agent.

New noninvasive methods to diagnose vesicoureteral reflux

PURPOSE OF REVIEW

The undesirable nature of bladder imaging in children for vesicoureteral reflux detection makes the search for noninvasive bladder imaging methods and devices an urgent concern.

RECENT FINDINGS

Ultrasound imaging of the bladder aided by contrast agents can be performed without ionizing radiation. However, urethral catheterization and contrast instillation is still necessary. The accuracy and reliability are still significant problems with this method. A new method of 'hiding' gadolinium in lysosomes followed by external energy application to rupture the lysosomes releasing the gadolinium for MRI holds future hope, but this research is in its infancy. A novel method to apply external microwave energy to warm the bladder urine with microwave kidney temperature monitoring is being developed. Temperature changes noted in the kidney after bladder warming would indicate vesicoureteral reflux. Further studies are ongoing.

SUMMARY

Ultrasonography imaging of the bladder to find vesicoureteral reflux has yet to be refined enough to be accurate and reliable for clinical use. MRI studies are in their infancy but may hold future benefit. Noninvasive bladder heating and kidney temperature monitoring is showing promise in animal studies to be a completely noninvasive reflux detection device.

Echocontrast cystosonography versus micturating cystourethrography in the detection of vesicoureteric reflux

Purpose:

To compare echocontrast cystosonography (ECS) using in-vivo agitated saline with fluoroscopic micturating cystourethrography (MCU) in the detection and grading of vesicoureteric reflux (VUR).

Materials and methods:

This was a prospective study of 25 children, who had MCU between 2007 and 2009. ECS was performed and findings documented prior to MCU. Baseline renal and bladder sonograms were obtained. The bladder was filled with normal saline followed by introduction of 10–20 mls of air to generate microbubbles. Detection of VUR was based on two sonographic criteria: (1) presence of microbubbles in the pelvicaliceal system (PCS), and (2) increase in dilatation of the PCS. VUR was graded as (1) Grade I: microbubbles seen in ureter only; (2) Grade II: microbubbles seen in non-dilated PCS; and (3) Grade III-V: microbubbles seen in dilated PCS. The ECS findings were compared using MCU as the gold standard.

Results:

Of the 50 kidney-ureter (K-U) units studied, ECS detected 9 of 10 K-U units with VUR on MCU. ECS did not detect a Grade II VUR. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value for criterion 1 was 90%, 87.5%, 88%, 64.3% and 97%, respectively, compared to criterion 2 which was 70%, 90%, 86%, 64% and 92%, respectively. The grading of VUR was similar on both ECS and MCU except for one case.

Conclusion:

ECS using agitated saline was a sensitive technique for the detection of VUR. ECS grading was comparable with MCU grading of VUR.

Pediatric uroradiology: state of the art

Recent years have witnessed major strides in imaging modalities, including US and contrast-enhanced voiding urosonography, fluoroscopy, CT and MRI, and these have significantly impacted paediatric uroradiology. The trend is towards reduced or no radiation exposure and combined morphological and functional imaging. This review presents the currently available and recommended modalities in modern paediatric uroradiology practice.