Low contrast dose voiding urosonography in children with phase inversion imaging

Abstract

Voiding urosonography (VUS) using a microbubble contrast agent has been introduced as an alternative technique in the diagnosis of vesicoureteral reflux (VUR). This study was undertaken to assess if phase inversion ultrasound (PIUS), a recent microbubble specific imaging technique, has advantages over fundamental in VUS and if it allows a reduction of contrast agent dose. Forty-three children with suspected VUR (aged 3 days-12 years, average of 3.9 years) with 92 kidney-ureter units (KUU) were included. Everyone obtained a baseline US scan that was followed by VUS using Levovist as the contrast agent. Constant switching between fundamental and PIUS performed the enhanced part for comparison. Every child underwent VCUG immediately afterwards. Contrast enhancement was stronger and longer lasting on PIUS than on fundamental US in all 43 cases. Reflux was detected in a total of 21 KUU, out of 92 KUU (23%). PIUS revealed VUR in 18; fundamental in 14 KUU and VCUG depicted 16 cases of reflux (p> or =0.29). The mean volume of Levovist dose administered to the bladder was 7.4+/-3.4% of the bladder volume. VUS using PI mode provided considerably stronger and longer enhancement and slightly improved the detection of VUR. It allowed a reduction of contrast dose and cost by approximately 35% over current dose recommendations for fundamental US.

Cyclic contrast-enhanced harmonic voiding urosonography for the evaluation of reflux. Can we keep the cost of the examination low?

“…The number of microbubbles present on the second cycle was enough to produce diagnostic images in 96% of our patients. It should be mentioned, however, that the use of a contrast-specific harmonic mode is a prerequisite to increase the sensitivity of the method to disclose refluxing microbubbles significantly [26][27][28].…”

“…However, both methods involve ionizing radiation, although with DRNC it is much less than with VCUG [13,14]. To overcome this problem, US methods have been developed for the evaluation of VUR utilizing air [34], air bubbles in shaken saline [35], sonicated albumin [36,37] and, more recently, special US contrast media made from galactose suspension [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. These are used to enhance the ability of US to detect VUR.…”

“…Contrast-enhanced voiding urosonography (VUS) with microbubbles containing contrast medium (CM) made of galactose-palmitic acid (SH U 508 A, Levovist; Schering, Berlin, Germany) has been used for the last 10 years and has been found to be equally sensitive compared to VCUG and DRNC [15][16][17][18][19][20][21][22][23][24][25]. Harmonic imaging has been shown to be significantly better at depicting microbubbles in the ureters and pelvicalyceal system [26][27][28]. Performing cyclic VUS further increases the sensitivity for detecting reflux, even without harmonic imaging [29,30].…”

Voiding Ultrasonography: Evaluation of the Detection of Vesicoureteral Reflux Based on the Review of Digital Ultrasound Clips

“…The tendency to overgrade reflux may be explained in a similar way. Although promising, non-linear imaging such as pulse inversion mode used in our protocol is motion sensitive [32], and may produce bright artefacts resulting from rapid tissue movements (i. e. bowel loops in the pelvis or pulsa-tility from vessels around the renal pelvis) which may be confused with microbubbles [16], as reported by reviewers in our study, especially in non-dilated pelvicalyceal cavities. We also observed a number of false-negative VUS, mainly grade 1 (n = 10) and grade 2 (n = 8).…”

Intraduktale Applikation von Levovist®in Speicheldrüsenausführungsgänge am Tiermodell

“…Bei niedrigen Konzentrationen steigt die R ü ckstreuung an und bei hohen Konzentrationen dominiert die Abschw ä chung der Schallwellen. In Anlehnung an Ergebnisse aus der Kinderurologie [9] wurde in dieser Versuchsreihe zur Darstellung der Speichelgangsysteme eine Levovistkonzentration von 300 mg / ml gew ä hlt. Aus der Erfahrung in der urethralen Gangdarstellung sollte in dieser Versuchsreihe eine Abschw ä chung des Schallsignals durch zu hohe Levovistkonzentrationen aber auch eine zu hohe Refl exion der Ultraschallwellen mit einer Signal ü bersteuerung vermieden werden.…”