Ureteric jet Doppler waveform: is it a reliable predictor of vesicoureteric reflux in children?

Color Doppler Ultrasound's Utility in Detecting Vesicoureteral Reflux Using the Ureteral Jet Angle

OBJECTIVES

This study hypothesizes using color Doppler ultrasound to measure ureteral jet angles (UJA) as a diagnostic screening tool for reflux.

METHODS

The present prospective cohort study included 122 patients and 238 renal unit pediatric patients suspected of VUR who presented to our hospital between 2019 and 2021. All patients underwent ultrasonography and VCUG, and the UJA was measured color Doppler evaluation of the ureteral jet. The UJA was compared with the VCUG findings in patients with and without reflux. SPSS 26 was used to analyze the data.

RESULTS

A total of 96 patients and 139 renal units exhibited reflux. The mean ureteral jet angle in refluxing units was 60.47 + 16.66 degrees, whereas, it was 42.59 + 13.26 degrees in non-refluxing units, a significant difference between the two groups (P < .001). The mean ureteral jet angle was 42.59, 45.89, 60.32, 68.23, and 56.16, for reflux grading from 0 to 5 (except grade 1), respectively. The angle value in each reflux grade increased significantly except for grade 5. For reflux detection (grade I-V), a cut-off angle of 50 degrees was associated with sensitivity and specificity of 70 and 79, respectively. Grade IV/V reflux can be diagnosed with a sensitivity of 70% and specificity of 84% using a cut-off angle of 68 degrees or greater.

CONCLUSIONS

UJA detection via color Doppler ultrasound demonstrates high accuracy, is non-invasive method can be utilized as an alternative primary diagnostic tool or in follow-up cases of VUR in children.

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.

Off-label-use of sulfur-hexafluoride in voiding urosonography for diagnosis of vesicoureteral reflux in children: A survey on adverse events

AIM

To evaluate the risk profile of sulfur hexafluoride in voiding urosonography (VUS) based on a large cohort of children.

METHODS

Since 2011 sulfur hexafluoride (SH, SonoVue^®, Bracco, Italy) is the only ultrasound contrast available in the European Union and its use in children has not been approved. Within a 4-year-period, 531 children with suspected or proven vesicoureteral reflux (f/m = 478/53; mean age 4.9 years; 1 mo-25.2 years) following parental informed consent underwent VUS with administration of 2.6 ± 1.2 mL SH in a two-center study. A standardized telephone survey on adverse events was conducted three days later.

RESULTS

No acute adverse reactions were observed. The survey revealed subacute, mostly self-limited adverse events in 4.1% (22/531). The majority of observed adverse events (17/22) was not suspected to be caused by an allergic reaction: Five were related to catheter placement, three to reactivated urinary tract infections, five were associated with perineal disinfection before voiding urosonography or perineal dermatitis and four with a common cold. In five patients (0.9%) hints to a potential allergic cause were noted: Perineal urticaria was reported in three interviews and isolated, mild fever in two. These were minor self-limited adverse events with a subacute onset and no hospital admittance was necessary. Ninety-six point two percent of the parents would prefer future VUS examinations with use of SH.

CONCLUSION

No severe adverse events were observed and indications of self-limited minor allergic reactions related to intravesical administration of SH were reported in less than 1%.

Evaluation of ureteral jet dynamics in pediatric kidney stone formers: A cross-sectional study

INTRODUCTION

The risk of kidney stone formation increases with urinary stasis, which is associated with decreased peristaltism. The relationship between nonobstructive kidney stone formation and ureteral jet dynamics, which can be measured with Doppler ultrasonography (US) and provide information about ureteral peristaltism, has been demonstrated in adults.

OBJECTIVE

To investigate the relationship between ureteral jet dynamics, which provide information about ureteral peristaltism, and stone formation in children.

STUDY DESIGN

Children admitted to Dokuz Eylul University Hospital with flank pain, and asymptomatic age-matched children for the control group, were prospectively enrolled and underwent Doppler US for diagnostic reasons and bilateral ureteral jet flow measurements. Children diagnosed with unilateral nonobstructive lower pole kidney stones formed Group 1, and the control group, without any evidence of stone disease, formed Group 2. Ureteral jet dynamics were compared between the affected renal units in Group 1, and healthy renal units in Group 1 and Group 2.

RESULTS

A total of 32 children were included for each group. The mean average jet flow-rate (JETave (cm/second)) in affected renal units in Group 1 was found to be significantly lower than in the healthy renal units in Group 1 and left and right healthy renal units in Group 2 (P < 0.05). The continuous JETpattern rate in affected renal units in Group 1 was found to be significantly higher compared with healthy renal units in Groups 1 and 2 (P = 0.012) (Table). The odds ratio for kidney stone formation was 5.6 for renal units with JETave <9.5 cm/s when compared with renal units with JETave ≥9.5 cm/s.

DISCUSSION

In a recent study, it was demonstrated in adults that low ureteral jet flow-rate and continuous JETpattern were significantly higher in affected renal units. The findings in children were also similar to adults: the mean JETave was significantly lower and determination rate of continuous flow pattern was significantly higher in affected renal units.

CONCLUSIONS

Children with low JETave and continuous JETpattern as a sign of decreased ureteral peristaltism are at an increased risk of kidney stone formation. However, it is vital that further studies are conducted to elaborate on this topic.

Dimercaptosuccinic acid scan or ultrasound in screening for vesicoureteral reflux among children with urinary tract infections

BACKGROUND

There is considerable interest in detecting vesicoureteral reflux (VUR) because its presence, especially when severe, has been linked to an increased risk of urinary tract infections and renal scarring. Voiding cystourethrography (VCUG), also known as micturating cystourethrography, is the gold standard for the diagnosis of VUR, and the grading of its severity. Because VCUG requires bladder catheterisation and exposes children to radiation, there has been a growing interest in other screening strategies that could identify at-risk children without the risks and discomfort associated with VCUG.

OBJECTIVES

The objective of this review is to evaluate the accuracy of two alternative imaging tests - the dimercaptosuccinic acid renal scan (DMSA) and renal-bladder ultrasound (RBUS) - in diagnosing VUR and high-grade VUR (Grade III-V VUR).

SEARCH METHODS

We searched MEDLINE, EMBASE, BIOSIS, and the Cochrane Register of Diagnostic Test Accuracy Studies from 1985 to 31 March 2016. The reference lists of relevant review articles were searched to identify additional studies not found through the electronic search.

SELECTION CRITERIA

We considered published cross-sectional or cohort studies that compared the results of the index tests (DMSA scan or RBUS) with the results of radiographic VCUG in children less than 19 years of age with a culture-confirmed urinary tract infection.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the selection criteria to all citations and independently abstracted data. We used the bivariate model to calculate summary sensitivity and specificity values.

MAIN RESULTS

A total of 42 studies met our inclusion criteria. Twenty studies reported data on the test performance of RBUS in detecting VUR; the summary sensitivity and specificity estimates were 0.44 (95% CI 0.34 to 0.54) and 0.78 (95% CI 0.68 to 0.86), respectively. A total of 11 studies reported data on the test performance of RBUS in detecting high-grade VUR; the summary sensitivity and specificity estimates were 0.59 (95% CI 0.45 to 0.72) and 0.79 (95% CI 0.65 to 0.87), respectively. A total of 19 studies reported data on the test performance of DMSA in detecting VUR; the summary sensitivity and specificity estimates were 0.75 (95% CI 0.67 to 0.81) and 0.48 (95% CI 0.38 to 0.57), respectively. A total of 10 studies reported data on the accuracy of DMSA in detecting high-grade VUR. The summary sensitivity and specificity estimates were 0.93 (95% CI 0.77 to 0.98) and 0.44 (95% CI 0.33 to 0.56), respectively.

AUTHORS' CONCLUSIONS

Neither the renal ultrasound nor the DMSA scan is accurate enough to detect VUR (of all grades). Although a child with a negative DMSA test has an < 1% probability of having high-grade VUR, performing a screening DMSA will result in a large number of children falsely labelled as being at risk for high-grade VUR. Accordingly, the usefulness of the DMSA as a screening test for high-grade VUR should be questioned.

Vesicoureteral refux detection in children: a comparison of the midline-to-orifice distance measurement by ultrasound and voiding urosonography

BACKGROUND

Due to the questionable clinical role of vesicoureteral reflux (VUR) and the search for noninvasive, radiation-free procedures sufficiently reliable to detect VUR, we compared the correlation between the midline-to-orifice distance (MOD) measured by ultrasonography (US) and echo-enhanced voiding urosonography (VUS) for detecting VUR in children. The aim of the study was to determine whether measuring MOD by US could be a reliable predictor of VUR in children.

METHODS

A total of 116 children, aged 0.25-84 months, with 232 potentially refluxing units were investigated simultaneously by measuring the MOD and performing VUS. Indications for cystography were urinary tract infection and follow-up of a previously detected VUR. VUS was performed after the MOD measurement. The results were analyzed with VUS as the reference method.

RESULTS

The MOD was significantly larger in VUR grade III (10.7 mm; p = 0.003) and VUR grade II (9.9 mm; p = 0.001) refluxing units than in non-refluxing units (7.8 mm), even when controlling for the estimated volume/expected maximal capacity (Vest/Vmax) ratio. A MOD cutoff value of 7.4 mm was chosen as a predictor of either the presence or absence of VUR; the sensitivity and specificity of this cutoff measurement for VUR detection were found to be 89 and 24%, respectively.

CONCLUSIONS

Despite the statistically significant difference between the MOD of refluxing versus non-refluxing units identified in our study, the MOD measurement needs further evaluation to determine its potential value as a diagnostic tool for the detection of VUR.

Vesicoureteric reflux in children

Vesicoureteric reflux is defined as the retrograde passage of urine from the bladder into one or both ureters and often up to the kidneys, and mainly affects babies and infants. In severe cases dilatation of the ureter, renal pelvis, and calyces might be seen. Traditionally it was thought that only a low percentage of children have vesicoureteric reflux, but studies have suggested as many as 25-40% are affected. Guidelines recommend that the number of investigations for vesicoureteric reflux in children who have had a febrile urinary tract infection be reduced, but this approach is controversial. The recommendations also suggest that prophylactic antibiotics and surgery should be avoided in children with non-severe vesicoureteric reflux. In this Seminar I present data on the management of children with vesicoureteric reflux and give suggestions on how to navigate this difficult area.

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.

Does the ureteric jet Doppler waveform have a role in detecting vesicoureteric reflux?

Data reported in this issue of Pediatric Nephrology suggest that the ureteric jet Doppler waveform can predict the occurrence of vesicoureteric reflux (VUR). Many different methods are currently used to detect VUR, including traditional X-ray micturating cystourethrogram, indirect and direct nuclear imaging and contrast enhanced ultrasonography. These methods are invasive, do have some radiation burden and are also quite uncomfortable to paediatric patients. This relatively new non-invasive method is therefore of interest, but its efficacy needs to be confirmed in further studies and, in particular, in babies and infants before it can possibly be considered as a good method to provide clinical information on VUR. Once such studies have been performed, this method may also prove to be a useful approach to obtain modern knowledge on the occurrence of VUR in healthy children.

Detecting reflux: does ureteric jet Doppler waveform have a role?

BACKGROUND

Vesicoureteral reflux (VUR) has a prevalence of 30-40 % post-febrile urinary tract infection (UTI). If not detected early and treated, renal scarring, hypertension, and renal failure may occur. Micturating cystourethrography (MCU) is an invasive procedure associated with radiation exposure. Hence, this study aimed at evaluating the utility of ureteric jet Doppler waveform (UJDW) as a screening tool in detecting VUR, and at assessing the feasibility of performing it in children aged 2-4 years.

METHODS

Any child 2-18 years old who needed an MCU was included. Exclusion criteria were active UTI, indwelling catheter, and inability to drink the required amount of fluid. The UJDW was performed prior to the MCU.

RESULTS

One hundred eighty-two ureteric units were analyzed. Sensitivity and specificity of UJDW in detecting VUR was 80.3 and 87.9 %. Twenty-three children (45 ureteric units), aged 2-4 years were compared with 73 children (137 ureteric units), aged 5-18 years. Sensitivity and specificity of UJDW in detecting VUR in 2-4 years was 77.3 and 91.3 %, respectively; while in children ≥5 years, it was 81.8 and 87.1 %, respectively.

CONCLUSIONS

UJDW has a uniformly high specificity regardless of age or etiological groups, making it a good tool for follow-up. UJDW is a feasible technique, even in children aged 2-4 years.

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.

Voiding urosonography with US contrast agent for the diagnosis of vesicoureteric reflux in children: an update

Voiding urosonography (VUS) entails the intravesical administration of US contrast agent (USCA) for the diagnosis of vesicoureteric reflux (VUR). VUS is now recognized as a practical, safe, radiation-free modality with comparable or higher sensitivity than direct radionuclide cystography (DRNC) and voiding cystourethrography (VCUG), respectively. An extensive review of the literature regarding both the procedural aspects and comparative diagnostic values of VUS has been published (Darge Pediatr Radiol 38:40-63, 2008a, b). The aim of this review is to provide an update on various facets of VUS that have taken place since the publication of the above-mentioned two reviews.