Case of urethral duplication seen by voiding urosonography

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.

Voiding cysto-urethrography of complete urethral duplication in a child, a case report

Background

Urethral duplication is a very uncommon congenital anomaly that predominantly affects males. This condition is distinguished by the presence of two urethras, which might be incomplete or complete. The diagnosis of urethral duplication is very important, and missing this diagnosis leads to the delayed surgical correction of patients. Voiding cysto-urethrography is an important diagnostic method to diagnose the urethral duplication that can provide a standard view for surgical operation and determine the type of duplication.

Case presentation

In the present study, we report a 5-year-old boy with complete urethral duplication diagnosed via voiding cysto-urethrography in our medical center. We reviewed the classification of this anomaly, indications of surgery, the importance of voiding cysto-urethrography, and the role of other imaging modalities to diagnose the urethral duplication.

Conclusion

For children with a double urinary stream, a complete genital examination and radiological assessment are required not only to diagnose urethral duplication but also to determine the kind of urethral duplication and rule out related anomalies. These findings guide surgeons in planning the best treatment for the patients to prevent future complications. Voiding cysto-urethrography is one of the most useful and beneficial procedures to diagnose the urethral duplication which can be used as a first imaging modality, especially when there are double functional urethras.

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 voiding urosonography part 2: urethral imaging

Ultrasound (US) has been increasingly used as an important imaging tool to assess the urethra in children. The earliest reports of pediatric urethral sonography involved imaging the urethra in a non-voiding state, during physiological voiding of urine, and after instillation of saline. The introduction of US contrast agents has continued to improve visualization of urethral anatomy. Contrast-enhanced US of the urethra can be performed during the voiding phase of a standard contrast-enhanced voiding urosonography (ceVUS) exam or with retrograde instillation of a contrast agent, depending on the exam indication. Both techniques are well tolerated by children and provide accurate information about urethral pathology and periurethral soft tissues. This article reviews the technical aspects and imaging findings of urethral pathologies in children using contrast-enhanced US, both by the voiding and retrograde instillation techniques.

Assessment of distal ureteral and ureterovesical junction visualization on contrast-enhanced voiding urosonography

BACKGROUND

Contrast-enhanced voiding urosonography (CEVUS) uses intravesically administered microbubble contrast to detect vesicoureteral reflux (VUR) and urethral anomalies with ultrasound. Multiple studies have suggested CEVUS can replace voiding cystourethrogram (VCUG) as a radiation-free alternative. Analysis of the ureterovesical junction and ureters on VCUG documenting the ureterovesical junction position, ureteral duplication, periureteral diverticula and ureteroceles is important as anatomical variations may affect management and surgical approach.

OBJECTIVE

Our purpose was to assess distal ureteral and ureterovesical junction region visualization in children with VUR detected on CEVUS.

MATERIALS AND METHODS

CEVUS studies performed between June 2018 and March 2019 with reported VUR were retrospectively reviewed by two pediatric radiologists to confirm VUR and to qualitatively assess the ureterovesical junction region for each renal moiety using a 3-point scale for clear, limited or absent visualization of the distal ureter, ureterovesical junction, ureteral duplication, periureteral diverticula and ureteroceles.

RESULTS

Thirty-four studies with VUR on CEVUS were identified. Sixty-seven renal moieties were evaluated including a solitary kidney in one child. VUR was detected in 52 moieties by reader 1 and in 53 by reader 2. A single moiety with discrepancy between readers regarding VUR was excluded from statistical analysis. No diverticula were detected by either reader and one ureterocele was detected by both readers. Visualization of the ureterovesical junction was described as clear in 5/52, limited in 14/52 and absent in 33/52 refluxing renal moieties by reader 1 and as clear in 12/52, limited in 20/52 and absent in 20/52 by reader 2. The ureterovesical junction was clearly visualized in 5/52 (9.6%) by reader 1 and 12/52 (23.1%) by reader 2. The Kappa value of -0.29 (confidence interval [CI] -0.25, 0.21) reveals a lack of agreement between the readers for clear versus limited or absent ureterovesical junction visualization. Distal ureteral visualization was described as clear in 14/52, limited in 16/52 and absent in 22/52 refluxing renal moieties by reader 1 and as clear in 27/52, limited in 7/52 and absent in 18/52 by reader 2. The distal ureter was clearly visualized in 14/52 (26.9%) by reader 1 and 27/52 (51.9%) by reader 2. The Kappa of 0.43 (CI 0.22, 0.64) reveals moderate agreement between the readers for clear versus limited or absent distal ureteral visualization. Duplication of the renal collecting system was identified in 13/52 refluxing kidneys by reader 1 and 11/52 refluxing kidneys by reader 2. Visualization of ureteral duplication was described as clear in 9, limited in 4 and absent in 39 of 52 refluxing renal moieties by reader 1 and as clear in 9, limited in 2 and absent in 41 by reader 2. Ureteral duplication was clearly visualized in 9/52 (17.3%) by reader 1 and 9/52 (17.3%) by reader 2. Kappa of 0.87 (CI 0.68, 1) reveals high agreement between the readers for clear versus limited or absent identification of ureteral duplication.

CONCLUSION

The distal ureter and ureterovesical junction region frequently are not clearly visualized in refluxing renal moieties on CEVUS. Awareness of this limitation is important as there may be implications when evaluating patients for surgical management of VUR.

Contrast-enhanced voiding urosonography: A new, radiation-free, alternative method for imaging of urinary bladder and urethra in healthy dogs

Contrast-enhanced voiding urosonography (CE-VUS) has been generally considered as a promising tool to diagnose vesicoureteral reflux and abnormalities in lower urinary tract in human patients, especially in children. The purpose of this prospective study is to evaluate the quality of images of the urinary bladder and urethra obtained by CE-VUS using a second-generation ultrasound contrast agent (SonoVue®) in healthy dogs and to investigate the safety profile of SonoVue® after intravesical administration. Eighty-four CE-VUS examinations with SonoVue® were successfully performed in both unsedated (39/84) and sedated (45/84) dogs. Contrast-enhanced voiding urosonography examination of urinary bladder was technically successful in all (84/84) dogs. The image quality was not considered adequate in five (5/84) dogs including three dogs in whom layering of contrast media during filling phase was observed and two dogs with premature destruction of microbubbles. In these five dogs, the problem was readily recognized and corrected such that the procedure was still successfully undertaken. The assessment of the urethra during spontaneous micturition was successfully performed in all (84/84) dogs in whom voiding was elicited during the examination. No side effects were observed after intravesical application of SonoVue®. This study demonstrates that CE-VUS is a feasible and valuable technique to evaluate low urinary tract morphology and function in dogs. Based on our review of the literature, there are no published reports about the use of this method in dogs.

Complete Urethral Duplication: Case Report and Literature Review

Urethral duplication (UD) is a rare-congenital anomaly that can affect the genito-urinary system. The aim of this case report is to show our experience in this case, including the investigation and operative techniques that we utilized. In the literature review, we will show that different types of duplication, radiological investigations, and surgical techniques have been used to treat this condition.

Case series: Comparison of contrast-enhanced genitosonography (ceGS) to fluoroscopy and cone-beam computed tomography in patients with urogenital sinus and the cloacal malformation

In this case series, contrast enhanced genitosonography is compared to genitography performed using fluoroscopy and cone-beam computed tomography in patients with urogenital sinus and the cloacal malformation. The method of contrast enhanced genitosonography is described, including contrast preparation, contrast administration, ultrasound imaging approaches, as well as the benefits and potential pitfalls of this technique compared to fluoroscopy and computed tomography.

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.