Contrast-enhanced gray-scale and color Doppler voiding urosonography versus voiding cystourethrography in the diagnosis and grading of vesicoureteral reflux.

PURPOSE: The purpose of this study was to compare contrast-enhanced gray-scale voiding urosonography (CE-VUS) and contrast-enhanced color Doppler voiding urosonography (CE-CDVUS) with voiding cystourethrography (VCUG) to verify whether the use of color Doppler imaging improves the diagnosis and grading of vesicoureteral reflux (VUR).

METHODS: In 74 patients, CE-VUS and CE-CDVUS were compared with VCUG, which was used as the gold standard. SHU 508 A (Levovist) was used as the echo-enhancing contrast agent. VUR was diagnosed if hyperechoic dots or color signals were visualized in the ureter on sonograms. VUR grading was based on morphologic and dynamic findings on CE-VUS and morphologic and color findings on CE-CDVUS. VCUG was performed conventionally, and grading by VCUG was in accordance with the international system of radiographic VUR grading. Patients who voided during 1 examination only (either CE-VUS and CE-CDVUS or VCUG) were excluded from the study. Agreement between the results of CE-VUS and VCUG and between those of CE-CDVUS and VCUG in diagnosing VUR was calculated by kappa statistics. CE-VUS and CE-CDVUS were compared for diagnostic accuracy by the McNemar test.

RESULTS: The agreement between CE-VUS and VCUG in predicting VUR was 90% (kappa score, 0.77; p < 0.001). The agreement between CE-CDVUS and VCUG was 96% (kappa score, 0.91; p < 0.001). CE-CDVUS showed a significantly higher diagnostic accuracy than did CE-VUS (96% versus 90% of cases correctly classified; McNemar chi2 = 4; p < 0.05). This was mainly related to the lower number of false-negative results for grade I and grade II VUR when CE-CDVUS was used.

CONCLUSIONS: The use of color Doppler imaging significantly improves the accuracy of contrast voiding urosonography in the detection and grading of VUR.