Interaction of normal saline solution with ultrasound contrast medium: significant implication for sonographic diagnosis of vesicoureteral reflux.

The sonographic diagnosis of vesicoureteral reflux with intravesical administration of ultrasound contrast media is on the rise. In few cases did we encounter rapid dissolution of microbubbles in the bladder filled with normal saline. The aim of this study was to find out whether there is any interaction between normal saline and ultrasound contrast media and, if so, to elucidate the cause for the interaction. In an in vitro experimental setup the mixtures of various normal saline solutions and a galactose-based ultrasound contrast medium (Levovist) were scanned under pre-defined parameters. The duration of contrast was determined. Oxygen concentration of the solutions was measured (pO(2) and O(2) mg/l). The US contrast medium had significantly longer contrast duration when mixed with normal saline from plastic containers rather than glass containers. The contrast duration difference was even more between normal saline from containers sealed under vacuum and those not sealed under vacuum: 0.7 and 12 min, respectively. The oxygen concentration in normal saline from vacuum-sealed containers is one-third or less that from non-vacuum-sealed containers. The high concentration of dissolved oxygen in the normal saline seems to prevent the diffusion of air from the microbubbles into the solution and thus their collapse. Desaturated normal saline has detrimental effect on microbubbles of the galactose-based US contrast medium. For the purpose of filling the bladder during contrast-enhanced voiding urosonography only normal saline solution from non-vacuum-sealed containers should be used. For practical purposes, normal saline from plastic containers is safest.

Vesicoureteral reflux grading in contrast-enhanced voiding urosonography.

INTRODUCTION AND OBJECTIVE: The sonographic diagnosis of vesicoureteral reflux (VUR) with contrast-enhanced voiding urosonography (VUS) is gradually increasing. With the introduction of VUS as part of the routine diagnostic imaging modalities for reflux significant reduction in the number of voiding cystourethrographies (VCUG) was possible. Like in VCUG grading of reflux in VUS is becoming more and more relevant. The aim of this study was to find out if there are any sonomorphologic and sonomorphometric parameters that would correlate with reflux grading in VCUG. Furthermore, a reflux grading system for VUS is proposed and the correlation of this grading system tested with the one of VCUG. PATIENTS AND METHODS: In one examination session a total of 186 children underwent both VUS and VCUG of whom 89 had VUR in at least one and the same kidney-ureter-unit (KUU) in both diagnostic imagings. The VUS was conducted with intravesical administration of ultrasound (US) contrast medium (Levovist). Ureteral and pelvicalyceal dilatations before administration of US contrast medium and during reflux were documented. Renal pelvic diameter was measured. The density of microbubbles in the renal pelves was scored on a scale of 1-3 (low to high). A grading system for reflux in VUS was set up similar to the international reflux grading system for VCUG with the addition of one more differentiation parameter, namely whether the reflux was primarily in a dilated or non-dilated urinary tract. Reflux grades in VUS were compared with those in VCUG. RESULTS: None of the sonomorphologic and sonomorphometric parameters demonstrated any clear cut finding that would simplify reflux grading in VUS. In 59/95 (62%) KUUs the reflux grades were the same in both examinations. In 10/95 (11%) and 26/95 (27%) KUUs, the reflux was graded lower or higher, respectively, in VUS than in VCUG. Fifty-seven percent were in a primarily dilated system and the remaining 43% in a non-dilated one. Seventy percent of KUUs diagnosed as having grade I reflux in VCUG, showed as grade 2 on VUS. CONCLUSIONS: A reflux grading system similar to the one used in VCUG can be applied in VUS. Adding the parameter reflux into a primarily dilated or non-dilated ureter and/or pelvicalyceal system may bring in a further dimension to the reflux grading in VUS. Most of the refluxes labelled as grade I in VCUG are actually grade II or higher.

Diameter of the infrarenal aorta and the iliac arteries in children: ultrasound measurements.

BACKGROUND: In adults, the diameters of the infrarenal abdominal aorta and the iliac vessels on ultrasound (US) are known. Similar values have not yet been reported in children. The purpose of this study was to establish a nomogram for these diameters in children. Therefore, the aim is to delineate another factor to limit intraoperative graft lost. METHODS: Studies were performed in 176 healthy children from 1 to 16 years of age. The diameters of the aorta and iliac arteries were measured by B-mode ultrasound at predefined sites. A correlation of the vessel diameter, age, gender, weight, height, body mass index, and body surface area (BSA) was performed. RESULTS: At all measured points, vessel diameters were significantly (P<0.0001) larger in boys than in girls. There was a significant (P<0.0001) increase of all the vessel diameters over age in both sexes. Vessel diameters correlate positively with age, gender, weight, height, and BSA. The highest correlation was found to be with BSA (r > or = 0.8, P<0.0001). Nomograms for each arterial diameter could be established for males and females separately. CONCLUSION: Normal US values of the diameter of the infrarenal aorta and the iliac vessels have been determined for children. The change in diameter strongly correlates with BSA. The nomograms can be of great help in the pretransplantation assessment of these vessels.

Diagnostic imaging of vesicoureteral reflux.

The diagnostic imaging modalities for vesicoureteral reflux in children comprise both radiologic and sonographic methods. The radiologic methods are voiding cystourethrography and radionuclide cystography. Voiding cystourethrography is the commonest imaging modality for reflux. With the introduction of pulsed fluoroscopy the radiation exposure of this examination is significantly curtailed. It is the imaging of first choice of the urethra. Various sonographic methods of reflux examination had been tried in the past. The real breakthrough came with the availability of stabilized US contrast media. The diagnostic accuracy of contrast-enhanced voiding urosonography has been found to be comparable to the radiologic methods. With the emergence of harmonic imaging the potential for significant improvement of the sonographic method has been achieved. Voiding urosonography is primarily performed in follow-up studies and as the first reflux examination in girls.