Color flow Doppler sonography in the diagnosis of vesicoureteric reflux

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.

Catheter-free methods for vesicoureteric reflux detection: our experience and a critical appraisal of existing data

In recent years, the exact role of vesicoureteric reflux (VUR) in general has become controversial, though in some groups of children the knowledge of the existence or non-existence of VUR is still a very important issue. The number of techniques available for the assessment of VUR is increasing, and a new classification taking into account their real characteristics (direct/indirect, catheter-using/catheter-free, radiation-giving/radiation-free) has been proposed. The purpose of the following review is to evaluate the currently available evidence supporting the use of various catheter-free methods for VUR detection. We believe that as the clinical role of VUR has been questioned, it is even more important for the method of its detection to be user-friendly as regards catheterisation, radiation and availability. There is still no evidence supporting the assertion that any of the catheter-free methods of VUR detection might be the optimal one for any child. However, there are some groups of children who would benefit from using them. New studies using new, catheter-free methods of VUR detection or a combination of two or more of the methods described may prove useful in improving sensitivity and providing additional data on this important issue.

How does study quality affect the results of a diagnostic meta-analysis?

BACKGROUND

The use of systematic literature review to inform evidence based practice in diagnostics is rapidly expanding. Although the primary diagnostic literature is extensive, studies are often of low methodological quality or poorly reported. There has been no rigorously evaluated, evidence based tool to assess the methodological quality of diagnostic studies. The primary objective of this study was to determine the extent to which variations in the quality of primary studies impact the results of a diagnostic meta-analysis and whether this differs with diagnostic test type. A secondary objective was to contribute to the evaluation of QUADAS, an evidence-based tool for the assessment of quality in diagnostic accuracy studies.

METHODS

This study was conducted as part of large systematic review of tests used in the diagnosis and further investigation of urinary tract infection (UTI) in children. All studies included in this review were assessed using QUADAS, an evidence-based tool for the assessment of quality in systematic reviews of diagnostic accuracy studies. The impact of individual components of QUADAS on a summary measure of diagnostic accuracy was investigated using regression analysis. The review divided the diagnosis and further investigation of UTI into the following three clinical stages: diagnosis of UTI, localisation of infection, and further investigation of the UTI. Each stage used different types of diagnostic test, which were considered to involve different quality concerns.

RESULTS

Many of the studies included in our review were poorly reported. The proportion of QUADAS items fulfilled was similar for studies in different sections of the review. However, as might be expected, the individual items fulfilled differed between the three clinical stages. Regression analysis found that different items showed a strong association with test performance for the different tests evaluated. These differences were observed both within and between the three clinical stages assessed by the review. The results of regression analyses were also affected by whether or not a weighting (by sample size) was applied. Our analysis was severely limited by the completeness of reporting and the differences between the index tests evaluated and the reference standards used to confirm diagnoses in the primary studies. Few tests were evaluated by sufficient studies to allow meaningful use of meta-analytic pooling and investigation of heterogeneity. This meant that further analysis to investigate heterogeneity could only be undertaken using a subset of studies, and that the findings are open to various interpretations.

CONCLUSION

Further work is needed to investigate the influence of methodological quality on the results of diagnostic meta-analyses. Large data sets of well-reported primary studies are needed to address this question. Without significant improvements in the completeness of reporting of primary studies, progress in this area will be limited.

No role for quality scores in systematic reviews of diagnostic accuracy studies

BACKGROUND

There is a lack of consensus regarding the use of quality scores in diagnostic systematic reviews. The objective of this study was to use different methods of weighting items included in a quality assessment tool for diagnostic accuracy studies (QUADAS) to produce an overall quality score, and to examine the effects of incorporating these into a systematic review.

METHODS

We developed five schemes for weighting QUADAS to produce quality scores. We used three methods to investigate the effects of quality scores on test performance. We used a set of 28 studies that assessed the accuracy of ultrasound for the diagnosis of vesico-ureteral reflux in children.

RESULTS

The different methods of weighting individual items from the same quality assessment tool produced different quality scores. The different scoring schemes ranked different studies in different orders; this was especially evident for the intermediate quality studies. Comparing the results of studies stratified as "high" and "low" quality based on quality scores resulted in different conclusions regarding the effects of quality on estimates of diagnostic accuracy depending on the method used to produce the quality score. A similar effect was observed when quality scores were included in meta-regression analysis as continuous variables, although the differences were less apparent.

CONCLUSION

Quality scores should not be incorporated into diagnostic systematic reviews. Incorporation of the results of the quality assessment into the systematic review should involve investigation of the association of individual quality items with estimates of diagnostic accuracy, rather than using a combined quality score.

Further investigation of confirmed urinary tract infection (UTI) in children under five years: a systematic review

BACKGROUND

Further investigation of confirmed UTI in children aims to prevent renal scarring and future complications.

METHODS

We conducted a systematic review to determine the most effective approach to the further investigation of confirmed urinary tract infection (UTI) in children under five years of age.

RESULTS

73 studies were included. Many studies had methodological limitations or were poorly reported. Effectiveness of further investigations: One study found that routine imaging did not lead to a reduction in recurrent UTIs or renal scarring. Diagnostic accuracy: The studies do not support the use of less invasive tests such as ultrasound as an alternative to renal scintigraphy, either to rule out infection of the upper urinary tract (LR- = 0.57, 95%CI: 0.47, 0.68) and thus to exclude patients from further investigation or to detect renal scarring (LR+ = 3.5, 95% CI: 2.5, 4.8). None of the tests investigated can accurately predict the development of renal scarring. The available evidence supports the consideration of contrast-enhanced ultrasound techniques for detecting vesico-ureteric reflux (VUR), as an alternative to micturating cystourethrography (MCUG) (LR+ = 14.1, 95% CI: 9.5, 20.8; LR- = 0.20, 95%CI: 0.13, 0.29); these techniques have the advantage of not requiring exposure to ionising radiation.

CONCLUSION

There is no evidence to support the clinical effectiveness of routine investigation of children with confirmed UTI. Primary research on the effectiveness, in terms of improved patient outcome, of testing at all stages in the investigation of confirmed urinary tract infection is urgently required.

Current status of vesicoureteral reflux diagnosis

In children, diagnostic imaging for vesicoureteral reflux (VUR) encompasses both radiologic and sonographic modalities. The former comprises voiding cystourethrography (VCUG), the most widespread method for examination for reflux, and radionuclide cystography (RNC). In RNC the radiation exposure is significantly less than in VCUG with continuous fluoroscopy, but the anatomic details depicted are much inferior. With the introduction of pulsed fluoroscopy, the radiation exposure of VCUG has been markedly curtailed. VCUG is the first imaging choice for the urethra. The sonographic diagnosis of VUR with the intravesical administration of an ultrasound (US) contrast agent-voiding urosonography (VUS)-is being used increasingly in the routine diagnostic imaging work-up of reflux. Various sonographic reflux examination methods had been tried in the past. The real breakthrough came with the availability of stabilized US contrast media. Further impetus came with the introduction of harmonic US imaging. The recent release of a second generation US contrast medium promises to make a further positive impact on VUS. The diagnostic accuracy of contrast-enhanced VUS has been found to be comparable to radiologic methods. VUS is primarily performed in follow-up studies and as the primary reflux examination modality in girls.

Detection of vesico-ureteric reflux in children by colour-flow Doppler ultrasonography

OBJECTIVES

To assess the findings of colour-flow Doppler ultrasonography (DUS) in the diagnosis of vesico-ureteric reflux (VUR), as an alternative to the primary diagnostic tool, voiding cysto-urethrography (VCUG).

PATIENTS AND METHODS

Thirty-five children (aged 2-15 years) were examined for VUR by DUS and standard VCUG. All patients underwent DUS and VCUG within 48 h but the findings of the latter were not reported to the ultrasonographer. The DUS was undertaken using a colour Doppler real-time system; a positive ultrasonogram was defined by visualizing Doppler signals from the bladder to the ureter during the course of bladder filling.

RESULTS

Of the 70 ureters assessed, 28 were refluxing on DUS and 29 on VCUG; there were two false-positive and three false-negative results. Comparing the two methods showed DUS to be 90% sensitive with a specificity of 93% for detecting VUR. Four patients underwent reimplantation during their treatment. DUS findings correlated well with standard VCUG in these patient as a method of follow-up.

CONCLUSION

DUS can be used as an alternative to standard VCUG for screening and following VUR. In addition, DUS avoids the danger of exposure to ionizing radiation and the unpleasant catheterization that many of these children fear.

Potential of modern sonographic techniques in paediatric uroradiology

OBJECTIVE

To describe the potential of modern sonographic techniques in paediatric uroradiology.

METHOD

Ultrasound (US)-now being the primary imaging tool-has revolutionised imaging diagnostic in the urinary tract. Constant developments and technical refinements have secured the role of US in uroradiology. Colour Doppler Sonography (CDS) and innovative applications such as the transperineal approach or application of m-mode US to the urinary tract have helped to develop US from just a basic tool to a sophisticated and respected method. The ongoing introduction of new and even more sophisticated methods further enhance the sonographic potential, which shall be demonstrated by a more detailed discussion of these methods.

RESULTS

Harmonic imaging, extended field of view US, amplitude coded CDS, echo-enhanced US, and three-dimensional US as the most recent new sonographic techniques are successfully applicable to paediatric urinary tract disease. They improve sonographic diagnosis in many conditions, such as detection of vesico-ureteral reflux, renal parenchymal volume assessment, comprehensive visualisation of hydronephrosis and complex pathology, evaluation of renal perfusional disturbances or defects, superior documentation with improved comparability for follow-up, or simply by offering clearer tissue delineation and differentiation.

CONCLUSION

Modern US techniques are successfully applicable to neonates, infants, and children, further boosting the value of US in the paediatric urinary tract. However, as handling became more sophisticated, and artefacts have to be considered, modern urosonography became not only a more powerful, but also a more demanding method, with the need for expert knowledge and dedicated training.

Vesicoureteral reflux: diagnosis and grading with echo-enhanced cystosonography versus voiding cystourethrography

PURPOSE

To evaluate the usefulness of echo-enhanced cystosonography compared with voiding cystourethrography (VCUG) for detecting and grading vesicoureteral reflux (VUR).

MATERIALS AND METHODS

Two hundred sixteen pediatric patients underwent cystosonography enhanced with SH U 508A, a galactose-based echo-enhancing agent. Sonograms of the kidneys and bladder were obtained before filling, during bladder filling, and during voiding. This examination was followed immediately with VCUG. Each kidney or portion of a kidney with its own complete collecting system was considered separately, for a total of 440 kidney units.

RESULTS

VUR was detected in 123 kidney units at cystosonography and in 104 at VCUG. In 401 kidney units, there was concordance between results at cystosonography and at VCUG regarding the presence or absence of VUR. Ninety-four kidney units showed VUR with both methods. Seventy-seven of the 94 refluxing units were depicted with the same grade of VUR with both modalities, and in 17 the VUR grade was greater at cystosonography than at VCUG. Twenty-nine of the 94 units showed VUR at only cystosonography, and 10 units at only VCUG. The McNemar test showed that cystosonography depicted a significantly (P = .003) higher number of units with VUR. By patient, VUR was depicted with both studies in 67 and with only one study in 25. VUR was seen at only cystosonography in 16 patients and at only VCUG in nine. The McNemar test for patients showed no significant difference between the two tests in detection of VUR.

CONCLUSION

Cystosonography with SH U 508A appears comparable to VCUG in the depiction of VUR.

Vesico-ureteral reflux: diagnosis and staging with voiding color Doppler US: preliminary experience

INTRODUCTION

The aim of this study is to assess the accuracy of a new US examination: 'voiding color Doppler US ' in the early diagnosis and staging of vesico-ureteral reflux (VUR). The contrast agent US was SH U 508A (Levovist, Schering, Berlin), which produces a chromatic accentuation of the signals picked up by the color Doppler US. Eighteen patients (10 females, eight males) were recruited for the study. In two patients a second examination was performed for follow-up after a VUR conservative therapy. All patients were taken under examination for the evaluation of possible VUR. In all patients the voiding color Doppler US was followed by voiding cystourethrography (VCUG) and the data obtained were compared.

MATERIALS AND METHODS

A total of 18 patients aged between 3 months and 10 years, were recruited for the study. The results of the examination were the following: urinary tract infections, follow-up of VUR after conservative or surgical therapy, miscellaneous indications. Voiding color Doppler US was performed, followed by a VCUG. The voiding color Doppler US consists in the trans-catheter introduction of a contrast agent SHU 508 A (Levovist, Schering, Ag. Berlin) into the bladder and a subsequent test with the color Doppler US to show or exclude the presence of reflux into the ureters and/or into the pyelo-caliceal cavity of the kidneys. After the introduction of the contrast agent US the ultrasound scanning of the bladder, the ureters and the pyelo-caliceal cavity was performed to examine the reflux degree. The ultrasonographic investigations were perfomed with AU 590 asyncronus US (Esaote Biomedica, Genova) with a 3.5 MHz convex probe.

RESULTS

After the trans-catheter introduction of the contrast agent US, vesico-ureteral reflux occured in 13 patients (77.2%). The reflux degree was also measured by means of ultrasound and was later confirmed by VCUG. The mean times of each examination were as follows: initial US, 10 min; catheterization, 8 min; voiding color Doppler US, 15 min; overall VCURG examination 10 min. The overall mean duration of the voiding color Doppler US examination was 33 min. The comparable mean time for VCUG, including the catheterization time, was 20 min. No reactions of intolerance to the ultrasound contrast agent occurred.

DISCUSSION AND CONCLUSIONS

The voiding color Doppler US test has evidenced in all patients the presence of the contrast agent US in the bladder after the introduction. In 13 patients (77.2%) with presence of VUR, the voiding color Doppler US test has established the reflux degree confirmed by cystourethrography. The superimposability of the data obtained with voiding color Doppler US and VCUG would seem to confirm the importance of this new ultrasonographic technique in the diagnosis and staging of VUR.

Diagnosis of vesico-ureteric reflux

The demonstration and grading of reflux is crucial in examination and follow-up of any child with upper urinary tract infection. A variety of factors can influence the occurrence of reflux, e.g. race, genetics, state of maturation of the ureterovesical valve, diuresis, infection and bladder dysfunction, including obstruction and neurogenic disorders. Even when reflux is investigated under strictly standardized conditions, two consecutive bladder fillings frequently show different grades of reflux. Voiding cystourethrography is, to date, the only method with a generally accepted, well-defined grading of reflux. It also allows detection of intrarenal reflux and anatomical and functional information about the bladder and urethra that is unobtainable by other methods. It is therefore usually considered the method of choice. Radionuclide cystography and, possibly, contrast enhanced ultrasonography can be complementary to voiding cystourethrography, but mainly for postoperative follow-up and screening of siblings.

Color flow Doppler sonography: a reliable alternative to voiding cystourethrogram in the diagnosis of vesicoureteral reflux in children

OBJECTIVES

In children with urinary tract infection, the incidence of vesicoureteral reflux (VUR) is nearly 30% to 40%. The standard for the diagnosis of VUR is voiding cystourethrography (VCUG). This study assessed the role of color flow Doppler sonography (CFDS) in the diagnosis of VUR and ureteral jets.

METHODS

CFDS imaging was performed in 36 patients aged 6 months to 13 years during a 4-year period. All patients underwent CFDS and VCUG within 24 to 48 hours, but the findings of the VCUG were not reported to the sonologist. The ultrasound examinations were done using a color Doppler real-time machine. Representative images of the bladder events were recorded with a multiformat camera and on VHS videotape.

RESULTS

The duration of the Doppler signal varied from 0.4 to 7.5 seconds. In 31 (86.1%) of 36 patients, the results of CFDS correlated well with VCUG findings. There were three false-negative and two false-positive results in the present study. Six patients underwent reimplantation during the course of their treatment. CFDS was used as a follow-up modality at the end of 6 months, and the results correlated well with standard VCUG in 4 of these patients. In the remaining 2 patients, only CFDS was performed and correlation with VCUG was not possible. VCUG was considered the reference standard in assessing the sensitivity of CFDS.

CONCLUSIONS

CFDS of the bladder during the filling and micturating phases is a reliable and sensitive modality for identifying VUR and demonstrating ureteral jets. CFDS nullifies the danger of exposure to ionizing radiation and avoids the unpleasant catheterization many of these children fear.

Reflux in young patients: comparison of voiding US of the bladder and retrovesical space with echo enhancement versus voiding cystourethrography for diagnosis

PURPOSE

To compare the usefulness of voiding US of the bladder and retrovesical space with echo enhancement with that of voiding cystourethrography (VCUG) for diagnosis of vesicoureteral reflux (VUR) and to assess patient tolerance of the echo-enhancing agent.

MATERIALS AND METHODS

One hundred eighty-eight patients (aged 5 days to 20 years) referred for investigation of VUR underwent voiding US with echo enhancement, which was followed by VCUG in 110 patients (226 kidney-ureter units). After US of the renal tract, the bladder was filled with normal saline solution. Then SU U 508 A, a galactose-based, microbubble-containing echo-enhancing agent, was administered. Reflux was diagnosed when microbubbles appeared in the ureter or pelvicalyceal system.

RESULTS

VUR was detected in 80 of the units with one (n = 18) or both (n = 62) methods. All grades of reflux were identified. In 15 units, reflux diagnosed at voiding US was not observed at VCUG; the reverse was true in three units. In 208 (92%) of the 226 kidney-ureter units, there was concordance between the two methods regarding the diagnosis or exclusion of VUR. The echo-enhancing agent was well tolerated.

CONCLUSION

SH U 508 A enhanced voiding US is as good as VCUG in the detection or exclusion of VUR and thus will make it possible to reduce the number of children having to be exposed to ionizing radiation.

Comparison of screening of vesicoureteral reflux with renal ultrasound and voiding cystourethrography

PURPOSE

To suggest a different method for diagnosing vesicoureteral reflux (VUR) in lieu of voiding cystourethrography (VCU), in order to prevent radiation exposure.

MATERIALS AND METHODS

Fifty-two ureterorenal units of 26 patients were evaluated ultrasonographically for visualizing the renal collecting systems, both before and after filling up the bladder with saline infusion. Every patient also underwent evaluation with VCU.

RESULTS

All patients with Grade 2 or higher degrees of VUR on VCU can be identified by ultrasound (USG). Overall sensitivity and specificity of this technique were 66.7% and 93.48%, respectively, in our patient group.

CONCLUSION

After being diagnosed with VCU initially a VUR patient can be effectively followed up by USG in order to prevent radiation exposure. Considering the clinical management of a patient with Grade 1 VUR which could not be detected with USG, it is concluded that failure to detect Grade 1 VUR will not be a handicap.

Detection of low-grade vesicoureteral reflux in children by color Doppler imaging mode

Vesicoureteral reflux (VUR) is common in children with urinary tract infections (UTI) and may result in renal scarring or reflux nephropathy. To date, the primary diagnostic tool has been voiding cystourethrography (VCUG). A new technique for evaluation of grade 1 and 2 VUR is described using color Doppler imaging-mode cystography (CDIMC): 77 children, aged 7 months to 14 years, were examined for VUR by CDIMC and standard VCUG. According to the established reflux sonography (US) using a real-time mode, all patients selected for this study had a normal urinary tract on conventional gray-scale US. We studied 154 ureters, and a total of 31 were found to be refluxing on CDIMC and 30 on VCUG. A positive sonogram was defined as visualization of Doppler signals from the bladder to the ureter during the course of bladder filling. Taking VCUG as the gold standard, we had ten false-positive findings. The false-positive rate of 18.5% may have been due to the shorter observation time of fluoroscopy. Comparison of the two methods shows CDIMC to be 70% sensitive with a specificity of 92% in the detection of VUR grade 1 and 2. To evaluate the incidence of asymptomatic low-grade VUR in a non-infected population, a second series of 38 children (19 males, 19 females) aged 3 to 15 years (mean 8.8 years) with normal urologic status and urine cultures were studied by color Doppler imaging mode (CDIM) for detection of asymptomatic low-grade VUR. Four children were found to have a unilateral refluxing ureter. The incidence of VUR in children with a normal urinary tract and no prior UTI was 10.5%. In conclusion, CDIMC can be used as a possible alternative to standard VCUG for the screening and follow-up of low-grade VUR. In addition, our study indicates that asymptomatic grade 1 and 2 reflux might be a physiological condition.