Abstract: Objective? To assess the accuracy of contrast-enhanced voiding urosonography (CeVUS) in diagnosing and grading of vesicoureteral reflux (VUR) and the consistency of the grading between the ultrasound observers. Methods? Thirtynine patients ( 79 Pyeloureteric units) examined by CeVUS and voiding cystourethrography (VCUG) were retrospectively analyzed. Based on the results of VCUG as the gold standard, the specificity, sensitivity and accuracy of grading diagnosis of CeVUS were calculated, and the consistency of different ultrasonic signs and grading evaluation of VUR between two ultrasound doctors was analyzed by Kappa test. Results? Compared with VCUG, the specificity and sensitivity of CeVUS in 79 PUUs was 90 . 6% and 89. 4%, respectively. The accuracy of grading of 42 pyeloureteral units with reflux was 90 . 5%, the accuracy of grade Ⅱ, Ⅲ, Ⅳ, V was 100%, 80 . 0%, 93 . 8% and 90 . 9%, respectively. The judgment of ureter development, ureter distortion, renal pelvis development, degree of renal pelvic dilatation, calyceal development, degree of calyceal dilatation, loss of renal pelvis contour between observers, the values of κ were 1 , 1 , 1 , 0 . 66 ( 0 . 52 - 0 . 80 ), 0 . 91 ( 0 . 82 - 1 . 00 ), 0 . 79 ( 0 . 70 - 0 . 89 ), and 0 . 69 ( 0 . 56 - 0 . 81 ) ( 95% confidence interval in brackets), respectively. The consistency of overall grading judgment was 0 . 87 ( 0 . 80 - 0 . 93 ). Conclusion? This study suggested that CeVUS with no ionizing radiation has a high accuracy in diagnosing and grading of VUR in children. It should be the first choice for the diagnosis and follow-up tool of VUR. When using CeVUS grading system for grading VUR, the overall consistency of the grading between the observers was excellent, which shows the feasibility of the CeVUS grading system even with different doctors.

Key words: vesicoureteral reflux;? contrast-enhanced voiding urosonography;? consistency among observers