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

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.

Maximizing the sensitivity of the indirect radionuclide cystogram: a retrospective audit

BACKGROUND

The indirect radionuclide cystogram (IRC) has generally been reported as being less sensitive for detecting vesico-ureteric reflux (VUR) than the micturating cystourethrogram (MCUG), so we modified it in an attempt to increase its sensitivity.

METHODS

We altered our routine IRC protocol by including the data obtained during failed voids, adding extra imaging sequences at intervals during bladder filling, and by using simple mathematical criteria to determine if VUR was present when visual imaging results were equivocal. We then retrospectively compared the VUR detection rates using the standard and modified techniques.

RESULTS

We assessed 707 renal units in 356 children over 3 years. We identified 91 cases of VUR using standard methodology, and 134 (47% more) with the modified technique. Of the extra 43 cases detected, 11 were noted during failed voids, ten were seen within a filling sequence, and 22 were inferred because the renal pelvic activity increased during an interval between two imaging sequences, while the bladder was filling. Mathematical evaluation was helpful in the 39 cases where the increase in activity due to VUR was ≤6 standard deviations greater than the level of background variation in activity.

CONCLUSIONS

Additional imaging and mathematical assessment can significantly increase the sensitivity of the IRC for detecting VUR, possibly to equal that of the MCUG.

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.

Comparative study of color Doppler voiding urosonography without contrast enhancement and direct radionuclide voiding cystography for diagnosis of vesicoureteric reflux in children

OBJECTIVES

Most available studies investigating the diagnostic accuracy of color Doppler voiding urosonography in the detection of vesicoureteric reflux used an echo contrast agent. It is unknown whether echo contrast agents are necessary for diagnosis or follow-up of vesicoureteric reflux. We compared color Doppler voiding urosonography without contrast enhancement and direct radionuclide voiding cystography in the detection and grading of vesicoureteric reflux with respect to the sex and age of patients as well as the severity of reflux.

METHODS

In the 66 patients enrolled (56 girls and 10 boys), 132 renoureteral units were investigated. All patients under went Doppler voiding urosonography and direct radionuclide voiding cystography within 3 hours. Direct radionuclide voiding cystography was used as the reference standard.

RESULTS

Our results indicate good overall sensitivity (83%) and specificity (77%) for color Doppler voiding urosonography without contrast enhancement in comparison with direct radionuclide voiding cystography. As the age of the patients decreased, the sensitivity of urosonography increased, reaching 100% among patients younger than 1 year. In the comparison of different grades of reflux severity, we found that the sensitivity and specificity were elevated as the grade increased (both parameters reaching 100% in the most severe cases). Severity grading was equal between the two methods.

CONCLUSIONS

We have shown that Doppler voiding urosonography without contrast enhancement is a comparably reliable method versus direct radionuclide voiding cystography in the detection and grading of vesicoureteric reflux, especially at higher grades of reflux and in children younger than 1 year.