Voiding ultrasonography : evaluation of the detection of vesicoureteral reflux based on the review of digital ultrasound clips

PURPOSE: To evaluate the accuracy of voiding urosonography (VUS) compared to X-ray voiding cystoureterography (VCUG) for the detection and grading of vesicoureteral reflux (VUR) by standardised reading of digital clips obtained from VUS and digital images from VCUG. MATERIALS AND METHODS: Approval by the ethics committee was obtained, and written, informed consent was given. 130 children (94 girls and 36 boys, mean age of 4.4 years) underwent VUS using Levovist (Schering, Germany) prior to VCUG. Digital VUS clips and digital VCUG images were reviewed by two groups of two radiologists. Results were mainly analysed in terms of reno-ureteral units (RUUs). Intra and interobserver reproducibility was estimated by calculation of kappa coefficient. Calculation of sensitivity and specificity of VUS was made in comparison with VCUG. RESULTS: Intraobserver reproducibility was good to moderate for the detection of VUR using VUS (κ = 0.67 and 0.53 for each reviewer respectively) and good for the grading of reflux (κ = 0.64 and 0.70). Interobserver reproducibility was excellent for the detection and grading of VUR using VCUG (κ = 0.89 and 0.91) but good to moderate for VUS (κ = 0.73 and 0.51). Compared to VCUG, sensitivity and specificity of VUS for the detection of VUR were 62.7 % and 83.4 %. Concordance for grading was moderate, with a higher grading using VUS. CONCLUSION: Real-time evaluation and diagnosis based on the review of VUS digital clips is achievable. However, there is a need for standardisation of digital records if a second reading by another radiologist or consideration by urologists is needed. Recent advances in US technology and the use of second-generation contrast agents would be promising to improve the feasibility, reproducibility and accuracy of the method.