Simultaneous Voiding Cystourethrography and Voiding Urosonography: An In Vitro and In Vivo Study

Contrast-enhanced voiding urosonography, a possible candidate for the diagnosis of vesicoureteral reflux in children and adolescents; a systematic review and meta-analysis

INTRODUCTION

The diagnostic value of contrast-enhanced voiding urosonography (ceVUS) in the diagnosis of vesicoureteral reflux (VUR) is still a subject of dispute.

OBJECTIVE

Assessing the diagnostic value of ceVUS in VUR, performing a systematic review and meta-analysis.

METHODS

An extensive search on Medline, Embase, Scopus and Web of Science databases was conducted by the end of 2020. The inclusion criteria were studies on the diagnostic value of ceVUS for VUR. Two independent researchers summarized the included articles and the findings were reported as area under the curve (AUC), sensitivity and specificity with a 95% confidence interval (95% CI).

RESULTS

Finally, the data of 36 articles were included in the present meta-analysis (2768 children). The VUS assessment showed that 1297 of the cases were true positives, 3661 were true negatives, 398 were false positives and 169 were false negatives. The AUC, sensitivity and specificity of ceVUS with the first-generation contrast agent in the diagnosis of VUR in children and adolescents were obtained as 0.97 (95% CI: 0.95, 0.98), 0.92 (95% CI: 0.86, 0.96) and 0.94 (95% CI: 0.95, 0.98), respectively. Moreover, AUC, sensitivity and specificity of ceVUS with the second-generation contrast agent were 0.97 (95% CI: 0.95, 0.98), 0.93 (95% CI: 0.86, 0.97) and 0.91 (95% CI: 0.86, 0.95).

CONCLUSION

The findings of the present study showed that diagnostic value of ceVUS with both first-generation and second-generation contrast agents for VUR, is in an excellent range. Although it seems that ceVUS may be applied as a radiation-free alternative to imaging techniques such as VCUG, the presence of 3% of false negatives in this test is a limitation. Since the lack of punctual management of VUR is associated with serious renal complications in children, future studies are recommended to be focused on the evaluation of the Benefit-risk evaluation of ceVUS.

Voiding urosonography with ultrasound contrast agents for the diagnosis of vesicoureteric reflux in children. I. Procedure

Voiding urosonography (VUS) encompasses examination of the urinary tract with intravesical administration of US contrast agent (UCA) for diagnosis of vesicoureteric reflux (VUR). The real breakthrough for US examination of VUR came with the availability of stabilized UCAs in the mid-1990s. This article presents a comprehensive review of various procedural aspects of VUS. Different US modalities are available for detecting the echogenic microbubbles: fundamental mode, colour Doppler US, harmonic imaging and dedicated contrast imaging with multiple display options. The reflux is graded (1 to 5) in a similar manner to the system used in voiding cystourethrography (VCUG). The most commonly used UCA for VUS, Levovist, is galactose-based and contains air-filled microbubbles. The recommended concentration is 300 mg/ml at a dose of 5-10%, or less than 5%, of the bladder filling volume when using fundamental or harmonic imaging modes, respectively. There are preliminary reports of VUS using a second-generation UCA, SonoVue. Here the UCA volume is less than 1% of the bladder filling volume. There is no specific contraindication to intravesical administration of UCA. The safety profile of intravesical Levovist is very high with no reports of side effects over a decade of use in VUS.

Applying the ALARA concept to the evaluation of vesicoureteric reflux

The voiding cystourethrogram (VCUG) is a widely used study to define lower urinary tract anatomy and to diagnose vesicoureteric reflux (VUR) in children. We examine the technical advances in the VCUG and other examinations for reflux that have reduced radiation exposure of children, and we give recommendations for the use of imaging studies in four groups of children: (1) children with urinary tract infection, (2) siblings of patients with VUR, (3) infants with antenatal hydronephrosis (ANH), and (4) children with a solitary functioning kidney. By performing examinations with little to no radiation, carefully selecting only the children who need imaging studies and judiciously timing follow-up examinations, we can reduce the radiation exposure of children being studied for reflux.