Ultrasound detection of vesicoureteral reflux in children.

PURPOSE: We present different ultrasound techniques to detect vesicoureteral reflux in children with special emphasis on voiding urosonography. MATERIALS AND METHODS: Urinary tract infection is a common problem in children that may be related to vesicoureteral reflux. Currently there is no consensus on investigations in children after the first urinary tract infection. The least invasive imaging with the smallest radiation burden should be used in children. Ultrasound to detect reflux meets several of these criteria. The development of echo enhancing agents has markedly improved reflux visualization by ultrasound. RESULTS: We discuss the clinical relevance of voiding urosonography. We reviewed the currently available literature and the results of our studies of this issue. We also describe our endeavors to avoid catheterization and detect vesicoureteral reflux based on various sonomorphological features, ie indirect voiding urosonography and ureteral jet Doppler waveform analysis, to avoid applying any substance into the bladder. CONCLUSIONS: Voiding urosonography is safe and reliable to detect vesicoureteral reflux. When indicated, considerably decreased radiation exposure can be achieved by voiding urosonography instead of established cystography methods. Indirect voiding urosonography and ureteral jet Doppler waveform analysis could be an alternative to invasive voiding cystography, at least in children older than 3 years.

Sensitivity of ultrasonography in detecting renal parenchymal defects: 6 years' follow-up.

While (99m)Tc-dimercaptosuccinic acid (DMSA) scanning is still considered the most accurate method for the assessment of renal parenchymal defects (RPDs), our study 6 years previously suggested that ultrasonography (US) could be a safe and efficient substitute for this purpose, provided that it is reliably performed and that renal function parameters are followed. By comparison of the original and follow-up study data from 67 children, the accuracy of our recommendations was re-evaluated. US was performed and renal function parameters investigated and correlated to the DMSA scans from the original study. US identified all six patients with clinically significant RPD and 52/61 with clinically insignificant RPDs, seen on the DMSA scans. Twenty two out of 22 severe RPDs, 21/23 moderate RPDs and 20/40 mild RPDs seen on the DMSA scans were detected by US. In ten cases normal US findings from the original study were rendered abnormal, correlating well with the DMSA scans with respect to RPD localization and kidney size. These results further support our previous suggestion that US is a safe and harmless alternative to DMSA scanning in the detection and follow-up of RPDs. While it cannot be excluded that small RPDs missed on the initial US might 'develop' clinical significance in later life, children with normal findings on initial US should have another sonogram done, at the shortest a year later, together with an investigation of renal function parameters.

PKD1 and PKD2 mutations in Slovenian families with autosomal dominant polycystic kidney disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is a genetically heterogeneous disorder caused by mutations in at least two different loci. Prior to performing mutation screening, if DNA samples of sufficient number of family members are available, it is worthwhile to assign the gene involved in disease progression by the genetic linkage analysis. METHODS: We collected samples from 36 Slovene ADPKD families and performed linkage analysis in 16 of them. Linkage was assessed by the use of microsatellite polymorphic markers, four in the case of PKD1 (KG8, AC2.5, CW3 and CW2) and five for PKD2 (D4S1534, D4S2929, D4S1542, D4S1563 and D4S423). Partial PKD1 mutation screening was undertaken by analysing exons 23 and 31-46 and PKD2 . RESULTS: Lod scores indicated linkage to PKD1 in six families and to PKD2 in two families. One family was linked to none and in seven families linkage to both genes was possible. Partial PKD1 mutation screening was performed in 33 patients (including 20 patients from the families where linkage analysis could not be performed). We analysed PKD2 in 2 patients where lod scores indicated linkage to PKD2 and in 7 families where linkage to both genes was possible. We detected six mutations and eight polymorphisms in PKD1 and one mutation and three polymorphisms in PKD2. CONCLUSION: In our study group of ADPKD patients we detected seven mutations: three frameshift, one missense, two nonsense and one putative splicing mutation. Three have been described previously and 4 are novel. Three newly described framesfift mutations in PKD1 seem to be associated with more severe clinical course of ADPKD. Previously described nonsense mutation in PKD2 seems to be associated with cysts in liver and milder clinical course.

Indirect voiding urosonography for detecting vesicoureteral reflux in children.

The purpose of our prospective study was to determine the value of indirect voiding urosonography without the use of contrast-media and without filling of the bladder through a catheter (IVUS) for detection of vesicoureteral reflux (VUR) in children, compared with echo-enhanced voiding urosonography (VUS). Among 57 children (45 girls and 12 boys, aged 2.7 to 12.0 years) admitted for echo-enhanced VUS either as part of routine evaluation after urinary tract infection (UTI) or follow-up of a previously detected VUR, IVUS was also successfully performed in 47 children. The results were considered positive when there was any increase in pelvis size and/or ureter lumen width during voiding. The overall sensitivity of IVUS in the detection of VUR was 49%, specificity 75%. The most accurate results were obtained with VUR grade III, where IVUS correctly detected 6 out of 7 cases, a sensitivity of 86%. The average increase of AP pelvis diameter during voiding was highly significant only in uretero-renal units with VUR grade III. Considering the obstacles in conducting the investigation and its relatively low overall sensitivity and specificity, it seems that IVUS is not sufficiently reliable to replace echo-enhanced VUS.

Cyclic voiding urosonography in detecting vesicoureteral reflux in children.

Three methods are currently used to identify vesicoureteral reflux (VUR) in children, namely X-ray voiding cystourethrography (VCUG), radionuclide voiding cystography (RVC), and, recently, echo-enhanced voiding urosonography (VUS). It is known that the sensitivity of VCUG and RVC for detecting VUR can be improved by using cyclic procedures, such as repeated bladder filling and voiding. The purpose of our prospective study was to evaluate whether the cyclic procedure is superior to the conventional (one cycle only) procedure in VUS also. VUS was performed in 49 patients, aged 1.4-15.8 years (mean 4.1 years). After the first micturition, the catheter was left in place and the whole procedure was repeated under the same conditions. The results of the first and second cycles and the combined procedure were compared. In the initial cycle, 7 of 35 (20%) refluxing renal units that were detected in the second cycle and 4 of 26 (15%) children with at least unilateral VUR were missed. Cyclic VUS detected 25% more VURs than the conventional (one cycle only) VUS ( P=0.049) and revealed 50% more VUR III than the first cycle. Our results suggest that cyclic VUS is superior to conventional VUS.

Sensitivity of ultrasonography in detecting renal parenchymal defects in children.

Renal parenchymal defects (RPD) -- scars, hypoplasia/dysplasia -- in children are a major risk factor for chronic renal failure. Most authors would agree that RPD should be detected and followed by a 99mTc-dimercaptosuccinic acid renal scan (DMSA), as ultrasonography (US) does not seem to be sensitive enough for this purpose. However, it might well be that DMSA is too sensitive and detects RPD that are too small to be clinically significant. The purpose of this study was to evaluate the sensitivity of US in identifying patients with clinically significant RPD and in detecting RPD of various grades as seen by DMSA. In 89 children with abnormal DMSA, a second DMSA, US, and other tests for evaluating renal function were performed at least 1 year after the first DMSA. The extent of RPD detected by DMSA and US was correlated with renal function parameters. In all 5 patients with diminished renal function, RPD were detected by both DMSA scan and US. In addition, US detected clinically insignificant RPD in 48 of 67 cases (71.6%). The present study has shown that, compared with DMSA, US is sensitive enough to detect clinically significant RPD in children. The substitution of DMSA with US would be beneficial, as this would eliminate radiation exposure, reduce costs, and increase availability.