Echo-enhanced color Doppler cystosonography of vesicoureteral reflux in children. Improvement by stimulated acoustic emission.

PURPOSE: To prospectively evaluate the potential of echo-enhanced color Doppler sonography (ee-CDS) using the acoustic stimulated emission technique in the diagnosis of vesicoureteral reflux (VUR) in children.
MATERIAL AND METHODS: 30 children (age: 0-9 years) with suspicion of VUR were submitted for echo-enhanced cystosonography (ee-CS) and conventional voiding cysto-urethrography (VCU). Conventional US and then color Doppler sonography (CDS) were performed after instillation of Levovist into the catheterized urinary bladder that had been prefilled with saline. Finally, output gain was increased in order to 'burst' the bubbles (= stimulated acoustic emission, burst-CS). Thereafter VCU was performed in the same session. The results of conventional ee-CS and burst-CS were compared to VCU findings.
RESULTS: Twenty-four refluxing systems were found in a total of 66 collecting systems by both techniques. Ee-CS and burst-CS detected VUR in four systems not seen by VCU (grades 1-4), but missed low-degree VUR in 2 cases. In low-degree VUR, burst-CS was particularly helpful in 9 patients with equivocal results on conventional ee-CS. In 6 of them, VUR was proven by burst-CS, the other 3 showed VURs neither on VCU nor on burst-CS.
CONCLUSION: Levovist ee-CS is feasible in the pediatric bladder. It enables reliable visualization of VUR in the renal collecting system. Burst-CS improves visualization of contrast reflux, particularly in non-dilative or minimally dilative VUR, which is sometimes difficult to depict with conventional ee-CS.