Voiding Cystourethrography In Children Research Articles

Contrast media viscosity and its potential effect on the diagnosis of vesicoureteral reflux in children.

To confirm that contrast-enhanced voiding cystourosonography (ceVUS) diagnoses more vesicoureteral reflux (VUR) than voiding cystourethrography (VCUG) and assess whether this could be explained by contrast agent viscosity differences. Children addressed for a VCUG for suspected or known VUR between April 2021 and June 2023 were prospectively included. CeVUS and VCUG were consecutively performed during the same procedure by two operators; for each pelviureteric unit (PUU), VUR presence was assessed and scored (I-V scale). At least 6 months later, three radiologists reassessed VUR grading on all ceVUS static images. The viscosity of the two contrast agents and of the urine were measured at 25 °C and 37 °C. Wilcoxon tests were used for comparisons and linear Cohen's Kappa coefficient for Interobserver and Intraobserver agreement. Eighty-nine children, representing 192 PUU, were included. VUR was detected in 54 PUUs by at least one technique, by both in 30/54, by ceVUS only in 21/54 (38.8%), and by VCUG only in 3/54 (5.5%). VUR grade was higher with ceVUS in 19/30 (63.3%, p < 0.0008) PUUs. The ceVUS agent viscosity at 25 °C/37 °C (1.13 cP/1.03 cP) was almost identical to urine viscosity (1.14 cP/1.02 cP) and it was respectively 8 and 6 times lower than VCUG contrast agent viscosity (9.44 cP/6.03 cP). The Cohen's kappa for ceVUS grading was between 0.75-0.97 (interobserver) and 0.93-0.98 (intraobserver). Our study confirms that ceVUS detects more VUR and grades them higher in comparison to VCUG in children. This could be explained by the lower viscosity of the US contrast agent. Question Why are there differences in detecting and grading VUR between ceVUS and VCUG? Finding VUR was detected by ceVUS or VCUG only in, respectively 38.8% and 5.5% of PUUs. VUR grade was higher with ceVUS in 63.3%. Clinical relevance The higher detection rate and grading of vesicoureteral reflux in children by ceVUS might be explained by the lower viscosity of its sonographic contrast agent. CeVUS might reproduce the urine movement in the urinary tract.

Incidence of febrile post-procedural urinary tract infection following voiding cystourethrography in children without prior urine culture.

Post-procedural urinary tract infections (ppUTIs) following voiding cystourethrography (VCUG) vary widely, with rates from 0 to 42%, though recent studies suggest rates typically below 5%. Verifying urine sterility before VCUG is traditionally done but questioned. This study assessed the 7-day ppUTI rate post-VCUG without prior urine sterility confirmation and identified associated risk factors. A retrospective review of VCUG cases in children under three years at a pediatric hospital over two years was conducted. Exclusions included neuropathic bladder, bladder exstrophy, pre-VCUG urine cultures, and lost-to-follow-up cases. Achieving a ppUTI rate below 5% would support safe VCUG practice without pre-urine culture. Of 318 VCUGs performed on 300 children, 248 (78%) were males (8% circumcised) with a median age of 5months. Retrograde VCUG was more common than suprapubic cystography (63% vs. 37%). Before the test, 33.6% received antibiotics, mostly prophylactically. Hydronephrosis was present in 66.4%, and 69% had a history of UTI. VCUG results were abnormal in 43% of cases: 85% had vesicoureteral reflux (VUR), 10% had posterior urethral valves (PUV), and 28% had other abnormalities. The 7-day ppUTI rate was 3.8%, with 67% of ppUTI cases having abnormal VCUG results versus 41% without ppUTI (p = 0.06). No significant risk factors for ppUTI were identified. Omitting systematic urine culture before VCUG was not associated with a high ppUTI rate, even in children with pre-existing urologic conditions or a history of UTI, indicating that VCUG can be safely performed without prior urine sterility confirmation. No risk factors for ppUTI were identified.

Comparison of voiding vesicoureteral urosonography with fluoroscopic voiding cystourethrography in children with vesicoureteral reflux.

To evaluate the value and compliance rate of voiding vesicoureteral urosonography in pediatric vesicoureteral reflux (VUR). This is a retrospective study. A total of 80 children with high-risk VUR admitted to Children's Hospital affiliated to Capital Medical University from December 2018 to December 2020 were selected. All patients underwent voiding urosonography (VUS) and fluoroscopic voiding cystourethrography (VCUG). The sensitivity and compliance of voiding vesicoureteral urosonography were compared, and its application value was evaluated. A total of 160 PUUs were examined, and all cases were normal. Among them, 56 PUUs had reflux (35.00%, 56/160), 46 PUUs had reflux under both examination methods (28.75%, 46/160), and 10 PUUs were only detected under VUS (6.25%, 10/160). Thirty-four cases of VUR (42.50%, 34/80) were diagnosed by VUS, among which 15 cases were bilateral reflux and 4 cases were unilateral reflux. Twenty-five cases (35.00%, 25/80) were diagnosed by VCUG, among which 10 cases were bilateral regurgitation and five cases were unilateral regurgitation. No significant difference was observed in the detection rate of reflux between the two methods (P=0.432). A total of 146 PUUs were found to be consistent between the two methods (91.25%, 160), including 2 Grade-I reflux, 6 Grade-II reflux, 14 Grade-III reflux, 12 Grade-IV reflux, eight Grade-V reflux, and 104 without reflux, demonstrating SATISFACTORY consistency between the two groups (Kappa=0.885). Voiding vesicoureteral urosonography has a high coincidence rate in the detection of vesicoureteral reflux in children.

Ultra low-dose VCUG in children using a modern flat detectorunit.

To assess dose area products (DAP) and effective doses (ED) of voiding cystourethrography (VCUG) in children using optimized protocols on a modern flat detector unit. DAP and ED were evaluated in 651 VCUG (316 girls, median age: 2.25years) between 2009 and 2012. DAP was analyzed in relation to patient characteristics (gender, age, presence of pathological findings) and experience of performing physician using analysis of variance. ED values were estimated using adapted conversion factors from the literature. Diagnostic image quality was validated by two experienced physicians using a 3-point scale. Median DAP/ED was 0.5cGycm(2)/4.56μSv (boys: 0.6cGycm(2)/6.16μSv; girls: 0.4cGycm(2)/3.54μSv). In 300 studies without pathologic findings DAP was 0.35cGycm(2), whereas 351 studies with pathologic findings had a median DAP of 0.7cGycm(2). No significant relationship between DAP and experience of radiologist was observed. Image validation resulted in an overall good to excellent rating. DAP and ED can be markedly reduced in paediatric VCUG performed with optimized protocols on modern equipment without a noticeable decrease in diagnostic image quality. • Voiding cystourethrography is a comprehensive examination in diagnosing vesicoureteral reflux (VUR). • Radiation reduction is achieved in VCUG through modern equipment and optimized protocols. • Low-dose VCUG is possible without noticeable decrease in diagnostic image quality.

Reappraisal of the effectiveness of 99mTc-dimercaptosuccinic acid scans for selective voiding cystourethrography in children with a first febrile urinary tract infection

Recent studies have yielded conflicting results regarding the ability of technetium-99m dimercaptosuccinic acid (99mTc-DMSA) renal scans for identifying high-grade vesicoureteral reflux (VUR) in children with a first febrile urinary tract infection (UTI). This study aimed to reevaluate the effectiveness of 99mTc-DMSA renal scans for selective voiding cystourethrography (VCUG) in children with a first febrile UTI. The medical records of children aged ≤ 5 years who were admitted with a first febrile UTI were retrospectively reviewed. Ultrasonography (US) and DMSA renal scans were performed within 3–5 days after admission, and VCUG was performed 7–10 days after antibiotics treatment. A total of 653 children were enrolled for analysis, including 579 patients aged < 2 years (Group A) and 74 patients aged 2–5 years (Group B). In Group A, DMSA scans were abnormal for 346 patients (59.8%), and normal for 233 patients (40.2%). High-grade VUR was present in 99 of 346 patients (28.9%) with abnormal DMSA scans, but present in only 16 of 233 patients (6.9%) with normal DMSA scans (p < 0.001). Regarding the prediction of high-grade VUR, the sensitivity and negative predictive value (NPV) for the DMSA scans were 86.1% and 93.1%, respectively. In Group B, DMSA scans were abnormal for 36 patients (48.6%), and normal for 38 patients (51.4%). High-grade VUR was present in 12 of 36 patients (33.3%) with abnormal DMSA scans, whereas none of the 38 patients with normal DMSA scans had high-grade VUR (p < 0.001). The sensitivity and NPV of the DMSA scans were both 100%. Using the selective VCUG strategy, approximately 40% of Group A patients and 50% of Group B patients could be spared an unnecessary VCUG, respectively. Our study results suggest that 99mTc-DMSA renal scans are effective in identifying children with a first febrile UTI for selective VCUG.

The value of direct radionuclide cystography in the detection of vesicoureteral reflux in children with normal voiding cystourethrography.

Vesicoureteral reflux (VUR) is one of the most important risk factors for urinary tract infection (UTI). Diagnosis and treatment of VUR is important to prevent irreversible complications, such as renal scarring and chronic renal failure. This study was conducted to assess the value of direct radionuclide cystography (DRNC) in the detection of VUR in children with UTI and a normal voiding cystourethrography (VCUG). DRNC was performed in 35 children with a normal VCUG after an episode of febrile UTI who had hydronephrosis or hydroureter, abnormal acute dimercaptosuccinic acid (DMSA) scan results and/or febrile UTI recurrence. This study was conducted in the nephrology department of Mofid Children's Hospital, Tehran (Iran). The results were statistically analyzed. Among the 70 ureters studied, 33 (49.1 %) were observed to have VUR. Of these, 17 (51.5 %) had mild, 14 (42.4 %) moderate, and 2 (6.1 %) severe reflux. A significant relationship was observed between DRNC results and DMSA renal scan findings (P < 0.05). Based on our results, we suggest that DRNC may reveal VUR despite a normal VCUG in children with hydronephrosis, abnormal acute DMSA, and/or recurrent febrile UTI.

Kidney Ultrasonography and Dimercaptosuccinic Acid Scans for Revealing Vesicoureteral Reflux in Children With Pyelonephritis: A 7-Year Prospective Cohort Study of 1500 Pyelonephritic Patients and 2986 Renal Units

Background: The presence of vesicoureteral reflux (VUR) has been documented in 1.3% of the general population, 70% of infants with urinary tract infection (UTI), and 15–25% of children with UTI. Objectives: The main aims of this prospective cohort study were to compare the efficiency of different imaging techniques [renal ultrasonography, cortical scintigraphy with technetium-99m dimercaptosuccinic acid (99mTc DMSA)] in detecting VUR in patients with acute pyelonephritis. Patients and Methods: Between June 2003 and March 2010, we recruited a prospective cohort of patients aged 1 month to 14 years. Pediatric patients with documented urinary tract infections and imaging evidence of upper tract involvement were examined by DMSA scintigraphy, renal ultrasonography, and voiding cystourethrography (VCUG). The assessments included UTI profiling, kidney ultrasonography, and DMSA scans. Data were expressed as mean ± SD. Statistical tests were two-tailed and were considered significant when P ≤ 0.05. Results: A total of 1500 pediatric patients were eligible to receive treatment for pyelonephritis. DMSA scans were normal in 20.2% of the patients and abnormal in the remaining 79.8%, and the kidney ultrasonographies yielded normal results in 68.5% of the patients and abnormal results in the remaining 31.5%. There was a significant difference between the ultrasonography reports of patients with normal and abnormal DMSA scans. The VCUG results were normal in 74.1% of the patients and indicated VUR in the remaining 25.9% (VUR grade I in 10.7%, grade II in 7.3%, grade III in 4.7%, grade IV in 1.7%, and grade V in 1.5%). The refluxes were unilateral in 62.9% of the patients and bilateral in the remaining 37.1%. We found a significant correlation between the presence of VUR in VCUG and urological abnormality in ultrasonography (r = 0.14, P < 0.001). The incidence of VUR among patients showing severe abnormalities in DMSA scintigraphy, was significantly higher than that among patients with normal DMSA results or those showing mild to moderate changes in DMSA scintigraphy. Conclusions: We concluded that kidney ultrasonography and DMSA scans can be performed before VCUG in children with UTI. In addition, we recommend performing VCUG in cases of pyelonephritis only when the patients show abnormal kidney ultrasonography or DMSA scan results.

Acute Tc-99m DMSA Scan for Identifying Dilating Vesicoureteral Reflux in Children: A Meta-analysis

Controversy exists regarding the type and/or sequence of imaging studies needed during the first febrile urinary tract infection (UTI) in young children. Several investigators have claimed that because acute-phase Tc-99m dimercaptosuccinic acid (DMSA) renal-scan results are abnormal in the presence of dilating vesicoureteral reflux, a normal DMSA-scan result makes voiding cystourethrography (VCUG) unnecessary in the primary examination of infants with UTI. To evaluate the accuracy of acute-phase DMSA scanning in identifying dilating (grades III through V) vesicoureteral reflux documented by VCUG in children with a first febrile UTI, we performed a meta-analysis of the accuracy of diagnostic tests as reported from relevant studies identified through the PubMed and Scopus databases. Patient-based and renal unit-based analyses were performed. Overall, 13 cohort studies were identified. Nine studies involved patients younger than 2 years, 3 involved children aged 16 years or younger, and 1 involved exclusively neonates. Girls constituted 22% to 85% of the involved children. Pooled (95% confidence intervals) sensitivity and specificity rates of DMSA scanning were 79% and 53%, respectively, for the patient-based analysis (8 studies) and 60% and 65% for the renal unit-based analysis (5 studies). The respective areas under the hierarchical summary receiver operating curves were 0.71 and 0.67. Marked statistical heterogeneity was observed in both analyses, as indicated by I(2) test values of 91% and 87%, respectively. Acute-phase DMSA renal scanning cannot be recommended as replacement for VCUG in the evaluation of young children with a first febrile UTI.

Uretrocistografía en Niños: Percepción de los Padres

Uretrocystography in Children: Parents' Perception Voiding cystourethrography (VCUG) has been usually consider as a painful and badly tolerated procedure in children. This opinion is not agree with local experience of the authors. Objective: To evaluate the parent's perception about VCUG in children before and after the procedure. Methods: In 2009, parents of children who came to Radiology Department for a VCUG completed an anonymous survey, including age and sex of their children, physician referent specialty, information received about the exam, expectation before and opinion after the procedure. Results: During 12 months 86 surveys were evaluated; patient's age was ranged between 1 month to 8 years with 52.3% (45) girls and 47.7% (41) males. Patients were referred from general pediatric in 59% or nephrology practice in 33%; 20% of the patients did not receive any information about the procedure before. About the expectation of VCUG, previous the exam, parents considered the examination as a pediatri- cian visit in 2.3%, uncomfortable in 26.7%, a little painful in 16.3%, painful in 21% and aggressive or terrible in 33.7%. After the examination, parents' opinion was: 24.4% as a pediatrician visit, 45.3% uncomfortable, 22.1% a little painful, 4.7% painful and 3.5% aggressive or terrible. The global parents' perception about VCUG after the exam improved in 66% cases, did not change in 29% and went worse in 5%. Conclusion: Parent's perception about VCUG in children signifi cantly improves after the procedure; in 91.8% the examina- tion was considered uncomfortable or only a little painful. (Key words: Cystography, urinary catherization, children). Rev Chil Pediatr 2010; 81 (4): 333-338

The Growing Role of Ultrasonography in Evaluating Children After Urinary Tract Infection

The purpose of this review is to advocate the use of ultrasonography (US) techniques in the work-up of children after a urinary tract infection (UTI). Currently, two major approaches are recognized. The first approach recommends looking for vesicoureteral reflux (VUR) in all children following a UTI. New techniques have been developed where, in the majority of cases, x-ray voiding cystourethrography (VCUG) is first substituted with radionuclide voiding cystography, and finally with echo-enhanced voiding urosonography, and this presented a significant improvement in diminishing the radiation burden on patients; yet there remained the drawback that catheterization is still necessary with all of these techniques. The introduction of catheter-free procedures would be a ‘final solution’, but these are yet to be validated. The second approach recommends screening for scars (mostly using a dimercaptosuccinic acid renal scan), while cystographies (preferably VCUG) are only performed in cases in which renal scarring has been confirmed. It was demonstrated that a dimercaptosuccinic acid renal scan can be safely and efficiently replaced by US, while voiding urosonography can substitute VCUG in children with confirmed scars in whom one believes VUR should be sought. From here on, catheter-free US techniques for VUR detection, although promising a ‘final solution’, still remain to be validated. In conclusion, regardless of which approach one believes is more appropriate in the management of children following a UTI, it is obvious that both protocols can be sufficiently fulfilled by the use of US techniques. At this time, more studies are needed to properly validate the latest noninvasive (catheter-free) US techniques for VUR detection.

Does a Normal DMSA Obviate the Performance of Voiding Cystourethrography in Evaluation of Young Children after Their First Urinary Tract Infection?

To determine whether a normal technetium-99m-labeled dimercaptosuccinic acid (DMSA) renal scan obviates the need for voiding cystourethrography (VCUG) in evaluating young children after their first urinary tract infection (UTI). This was a 10-year retrospective review of 142 children (age < or = 2 years, 77 boys and 65 girls) who had their first UTI and were admitted to a tertiary care general hospital. The association between DMSA renal scan results and VCUG results performed 48 hours and 1 month after diagnosis was evaluated. DMSA renal scans and VCUG were performed in 142 patients. Of these, 99 patients (69.7%) had evidence of pyelonephritis, although only 2 (1.4%) had evidence of renal scarring; 42 (29.6%) had vesicoureteral reflux (VUR) on VCUG. The sensitivity, specificity, positive and negative predictive values, and likelihood ratio negative for abnormalities on DMSA renal scans for detecting the the presence of VUR on VCUG were 88% (95% confidence interval [CI] = 73% to 100%), 36% (95% CI = 26% to 46%), 37% (95% CI = 27% to 46%), 88 % (95% CI = 73% to 100%), and 0.33 (95% CI = 0 to 0.88), respectively. Children with a negative DMSA renal scan during their first UTI episode rarely have VUR and may never have high-grade VUR. Avoiding VCUGs in children with negative DMSA renal scans could significantly reduce the use of this potentially traumatic test.

Biofeedback therapy expedites the resolution of reflux in older children.

In older children the spontaneous resolution rate of low grade vesicoureteral reflux is low and currently its management is controversial in regard to surgery versus prophylaxis versus observation alone. Bladder dysfunction in children with neurogenic bladders and to a less declarative degree in neurologically intact children has a role in the etiology or persistence of reflux. We determine the impact of biofeedback therapy on neurologically intact children with vesicoureteral reflux and detrusor-sphincter dyssynergia. Vesicoureteral reflux was detected by voiding cystourethrography in children evaluated for urinary tract infections. Children with breakthrough infections or dysfunctional voiding based on history underwent uroflowmetry with concomitant patch electromyography of the external sphincter. Dyssynergia was defined as increased or steady electromyography activity during micturition. Biofeedback was initially performed weekly and the interval increased as indicated. The goals were to eliminate dyssynergia and reduce or eliminate post-void residual urine. Voiding cystourethrography was performed 1 year later to determine the status of the reflux. Ureteral reimplantation was performed during the period of biofeedback when indicated. From February 1997 to March 2001, 25 children 6 to 10 years old (mean age 9) with vesicoureteral reflux and detrusor-sphincter dyssynergia were treated with biofeedback therapy. There were 31 units (5 bilateral) with reflux, which was grade I in 10, II in 15, III in 5 and IV in 1. Children underwent an average of 7 sessions of biofeedback (range 2 to 20). On followup voiding cystourethrography, vesicoureteral reflux resolved in 17 units (55%), grade improved in 5 (16%) and reflux remained unchanged in 9 (29%). All cured vesicoureteral reflux was grade I (8 cases) or II (9). Four children (5 renal units) underwent reimplantation. In cured children there were no breakthrough infections during or since therapy and post-void residual urine decreased from an average of 40% before to 10% after therapy. Symptoms of urgency, daytime wetting and hoarding of urine improved or were eliminated in all children with resolved vesicoureteral reflux. Treating external detrusor-sphincter dyssynergia in older children with low grade vesicoureteral reflux, with biofeedback results in 1-year resolution rates that are considerably greater than historical resolution rates. External detrusor-sphincter dyssynergia should be screened for in children when surgery or discontinuation of chemoprophylaxis is considered so that biofeedback can be started.

DOES URINARY TRACT ULTRASONOGRAPHY AT HOSPITALIZATION FOR ACUTE PYELONEPHRITIS PREDICT VESICOURETERAL REFLUX?

We evaluate the correlation between urinary tract ultrasound during hospitalization for acute pyelonephritis with subsequent voiding cystourethrography in children. Medical records were reviewed of 184 children up to 18 years old who were evaluated with ultrasound during hospitalization for acute pyelonephritis between January 1988 and January 1996. Followup voiding cystourethrography results were compared to the initial ultrasound findings. Ultrasound was performed at mean hospital day 2.1 and voiding cystourethrography was done 39 days later. Of the ultrasound studies 77 (42%) were abnormal, and two-thirds of these abnormalities were upper tract dilatation. Subsequent voiding cystourethrography was performed in 76% of the study population, including 67% of those with normal and 87% of those with abnormal ultrasound. Voiding cystourethrography revealed reflux in 39% of children with upper tract dilatation compared to 35% of those with normal and 36% with abnormal ultrasound for any reason. In addition, the severity of reflux on voiding cystourethrography could not be predicted by ultrasound findings. Ultrasound findings during acute pyelonephritis do not correlate with and are not predictive of the presence or grade of vesicoureteral reflux on subsequent voiding cystourethrography.

Predictors for abnormal voiding cystourethrography in pediatric patients undergoing renal transplant evaluation.

The role of pretransplant voiding cystourethrography (VCUG) in adults has been questioned owing to the low prevalence of abnormal findings. As there are no studies evaluating the relevance of VCUG in children and because vesicoureteral reflux (VUR) occurs with higher prevalence in children, we performed a retrospective cohort study to identify any predictors for abnormal VCUG. We reviewed 271 consecutive renal transplants performed between 1980 and 1997. By logistic regression, the etiology of end-stage renal disease (ESRD) and age at transplantation (Tx) were strong predictors of abnormal pretransplant VCUG findings in children. On multi-variate analysis, children with urologic etiologies of renal disease had an odds ratio (OR) of 16.5 (p < 0.0001) for abnormal VCUG as compared to children with non-urologic or acquired causes of ESRD. Similarly, children transplanted when younger than 8 yr of age had an OR of 3.0 (p = 0.0043) for having an abnormal VCUG when compared with older children. Finally, our analysis suggests that children with abnormal pretransplant VCUG findings, whether or not pretransplant surgical correction was performed, were over three-fold more likely to require post-transplant urologic surgery when compared to children with normal pretransplant VCUG. We conclude that urologic causes of ESRD and age under 8 yr are strong independent predictors of abnormal pretransplant VCUG findings, and that these findings are of clinical relevance both in deciding whether to pursue pretransplant VCUG and in the post-transplant course of the patient.

Radiation exposure in digital micturition cystourethrography in children. How much exposure by fluoroscopy?

Determination of the proportion of the dose-area product caused by fluoroscopy at voiding cystourethrography in children, using digital image intensifier technology. Using computer-assisted dosimetry, we determined the dose-area product and the respective proportions of the dose-area product caused by fluoroscopy and radiography as well as the number of radiographs taken at a given examination of 40 children (8 children less than 2 years old, 15 children between 2 and 6 years old and 17 children between 6 and 15 years old). The computer software program correctly differentiated between fluoroscopy and radiography in 80% of cases. Incorrect results were primarily observed in newborns and young children. The total radiation dose ranged in relation to patient age from 22 to 651 cGy x cm2. Fluoroscopy was responsible for an average 78% of the applied radiation dose. Computer-assisted dosimetry is useful in determining the proportion of the dose-area product caused by fluoroscopy in older children undergoing voiding cystourethrography. When image intensifier technology is used, this accounts for more than 75% of the total radiation dose. The method is not suitable for use in small children.