Vesicoureteric reflux in children: prediction with color Doppler imaging. Work in progress

Evaluation of the ureteral jet in dogs by using color Doppler ultrasonography

Ureteral jets are the result of a forceful ejection of urine from the vesicoureteral junction into the urinary bladder. By using color Doppler ultrasonography (US), we aimed to identify distinct ureteral jets in dogs, provide insight into ureteral obstruction, and facilitate study of urodynamics and vesicoureteric sphincter function via pulsed Doppler US. Color Doppler US was applied to detect urinary flow from the right ureteral orifices in eight healthy beagles. Under anesthesia, 0.9% saline (2.5 mL/kg/h) and furosemide (0.5 mg/kg) were administered intravenously to assist in detection of distinct ureteral jets and examine their frequency, velocity, duration, and waveform. In all dogs, ureteral jets were visualized under diuresis and anesthesia within 2 to 5 min (mean 3.57 ± 0.90 min) of the furosemide injection. Mean frequency, peak velocity, and duration of right ureteral jets in seven dogs in whom six ureteral jet waveform patterns were identified were 9.86 ± 3.09 jets/min, 34.07 ± 10.02 cm/sec, and 2.82 ± 1.08 sec, respectively. During the 10 min period starting 10 min after the initial jet appeared, only three waveforms were identified. Color Doppler US of ureteral jets may aid in assessing vesicoureteric sphincter function and ureteral abnormalities, such as ureteral obstruction, in dogs.

Vesicoureteral refux detection in children: a comparison of the midline-to-orifice distance measurement by ultrasound and voiding urosonography

BACKGROUND

Due to the questionable clinical role of vesicoureteral reflux (VUR) and the search for noninvasive, radiation-free procedures sufficiently reliable to detect VUR, we compared the correlation between the midline-to-orifice distance (MOD) measured by ultrasonography (US) and echo-enhanced voiding urosonography (VUS) for detecting VUR in children. The aim of the study was to determine whether measuring MOD by US could be a reliable predictor of VUR in children.

METHODS

A total of 116 children, aged 0.25-84 months, with 232 potentially refluxing units were investigated simultaneously by measuring the MOD and performing VUS. Indications for cystography were urinary tract infection and follow-up of a previously detected VUR. VUS was performed after the MOD measurement. The results were analyzed with VUS as the reference method.

RESULTS

The MOD was significantly larger in VUR grade III (10.7 mm; p = 0.003) and VUR grade II (9.9 mm; p = 0.001) refluxing units than in non-refluxing units (7.8 mm), even when controlling for the estimated volume/expected maximal capacity (Vest/Vmax) ratio. A MOD cutoff value of 7.4 mm was chosen as a predictor of either the presence or absence of VUR; the sensitivity and specificity of this cutoff measurement for VUR detection were found to be 89 and 24%, respectively.

CONCLUSIONS

Despite the statistically significant difference between the MOD of refluxing versus non-refluxing units identified in our study, the MOD measurement needs further evaluation to determine its potential value as a diagnostic tool for the detection of VUR.

Detecting reflux: does ureteric jet Doppler waveform have a role?

BACKGROUND

Vesicoureteral reflux (VUR) has a prevalence of 30-40 % post-febrile urinary tract infection (UTI). If not detected early and treated, renal scarring, hypertension, and renal failure may occur. Micturating cystourethrography (MCU) is an invasive procedure associated with radiation exposure. Hence, this study aimed at evaluating the utility of ureteric jet Doppler waveform (UJDW) as a screening tool in detecting VUR, and at assessing the feasibility of performing it in children aged 2-4 years.

METHODS

Any child 2-18 years old who needed an MCU was included. Exclusion criteria were active UTI, indwelling catheter, and inability to drink the required amount of fluid. The UJDW was performed prior to the MCU.

RESULTS

One hundred eighty-two ureteric units were analyzed. Sensitivity and specificity of UJDW in detecting VUR was 80.3 and 87.9 %. Twenty-three children (45 ureteric units), aged 2-4 years were compared with 73 children (137 ureteric units), aged 5-18 years. Sensitivity and specificity of UJDW in detecting VUR in 2-4 years was 77.3 and 91.3 %, respectively; while in children ≥5 years, it was 81.8 and 87.1 %, respectively.

CONCLUSIONS

UJDW has a uniformly high specificity regardless of age or etiological groups, making it a good tool for follow-up. UJDW is a feasible technique, even in children aged 2-4 years.

Non-invasive vesicoureteral reflux imaging

OBJECTIVE

To evaluate non-invasive and non-ionizing methods of determining the presence of vesicoureteral reflux (VUR) and to preview upcoming ideas that have the potential of finding VUR non-invasively.

MATERIALS AND METHODS

We performed a PubMed search using the terms 'vesicoureteral reflux/radiography', 'vesicoureteral reflux/ultrasonography' and 'magnetic resonance imaging/urologic disease'. We also included information from a recent American Academy of Pediatrics meeting and our own research.

RESULTS

Voiding ultrasonography is non-radiating and has undergone significant improvements recently. Best results require instillation of contrast through invasive catheter placement, and doubts regarding sensitivity and specificity are significant. Magnetic resonance cystograms are best with catheter-instilled contrast. They are expensive, require anesthesia or sedation, and are impractical. Horizon technologies include magnetic resonance cystogram with gadolinium 'activation' within the bladder. Another promising completely non-invasive method includes warming the bladder with microwaves and measuring kidney temperatures before and after warming. Detection of a rise in kidney temperatures would indicate VUR.

CONCLUSIONS

Voiding cystourethrography remains the gold standard in reflux diagnosis but is invasive and submits the child to ionizing radiation. Developing technologies need improvements and further research before they may have a role in significantly decreasing voiding cystourethrography use or replacing it completely.

Catheter-free methods for vesicoureteric reflux detection: our experience and a critical appraisal of existing data

In recent years, the exact role of vesicoureteric reflux (VUR) in general has become controversial, though in some groups of children the knowledge of the existence or non-existence of VUR is still a very important issue. The number of techniques available for the assessment of VUR is increasing, and a new classification taking into account their real characteristics (direct/indirect, catheter-using/catheter-free, radiation-giving/radiation-free) has been proposed. The purpose of the following review is to evaluate the currently available evidence supporting the use of various catheter-free methods for VUR detection. We believe that as the clinical role of VUR has been questioned, it is even more important for the method of its detection to be user-friendly as regards catheterisation, radiation and availability. There is still no evidence supporting the assertion that any of the catheter-free methods of VUR detection might be the optimal one for any child. However, there are some groups of children who would benefit from using them. New studies using new, catheter-free methods of VUR detection or a combination of two or more of the methods described may prove useful in improving sensitivity and providing additional data on this important issue.

Ureteric jet Doppler waveform: is it a reliable predictor of vesicoureteric reflux in children?

The purpose of our prospective study was to find out whether ureteric jet Doppler waveform (UJDW) could be a reliable predictor of vesicoureteral reflux (VUR) in children, compared with echo-enhanced voiding ultrasonography (VUS). Echo-enhanced VUS was performed in 75 children, 57 girls and 18 boys, aged 3 years to 12 years, following the accepted indications for this procedure. During the same procedure the measurement of UJDW was also performed and was considered to be successful (in 70 children) when at least ten UJDWs were recorded per ureteric unit. Depending on the shape of the UJDWs, the sequences were classified into three groups: monophasic, suggestive of VUR; complex, not suggestive of VUR; and mixed sequence, suggestive of VUR when a certain ratio between monophasic and complex UJDWs was achieved. When all three sequences were taken into account, the overall sensitivity and specificity of this method in detecting VUR were 88.5% and 82.3%, respectively. These values seem high enough for this method to be considered as a good alternative to invasive micturating cystographies in screening children for VUR.

[Doppler US of the urinary system and renal vessels in normal and pathologic conditions]

The interest of Doppler ultrasound (US) in urinary tract investigation has dramatically increased during the past 10 years. It can provide useful diagnostic informations in pedicular and intrarenal vascular disorders, some medical nephropathies, in the assessment of renal tumors and urinary tract disorders including urolithiasis, acute obstruction and ureteral reflux. Recent technical improvements including the development of US contrast agents (microbubbles) have contributed to increase the diagnostic accuracy of the technique.

Doppler waveforms of the ureteric jet: an overview and implications for the presence of a functional sphincter at the vesicoureteric junction

This paper is a comprehensive review of the Doppler waveform appearance of ureteric jets. Six jet waveform patterns have been identified: monophasic, biphasic, triphasic, polyphasic, square and continuous. Details of the physical properties of jet patterns and their changes under various physiological conditions are illustrated. The immature monophasic ureteric jet pattern is common in infancy and early childhood up to around 4 years of age. This pattern is also noted to have a high incidence in older children with urinary tract infection/vesicoureteric reflux, nocturnal enuresis and in other special physiological conditions such as in children undergoing general anaesthesia, in women during pregnancy, and in patients who have had ureteric transplantation. A hypothesis of dual myogenic and neurogenic components is proposed to explain the mode of action of the vesicoureteric junction (VUJ). The implication of this hypothesis is that it alters the scientific basis of the understanding of the VUJ. Furthermore, the application of colour Doppler US to ureteric jets may provide a non-invasive technique to study the physiology or pathophysiology of the VUJ in humans. This might shed light on new novel approaches to the monitoring and treatment of diseases related to VUJ function.

Magnetic resonance voiding cystourethrography for vesicoureteral reflux

PURPOSE

To assess the feasibility of magnetic resonance voiding cystourethrography (MRVCUG) using MR fluoroscopy for evaluation of vesicoureteral reflux (VUR), and its use as a noninvasive alternative to standard VCUG.

MATERIALS AND METHODS

A total of 22 MR studies of 16 patients (five months to 41 years old) with primary VUR diagnosed by standard VCUG were evaluated. Six patients underwent MR studies and standard VCUG pre- and postoperatively. MR fluoroscopy was executed with a non-enhanced heavily T2-weighted single-shot fast spin-echo (FSE) sequence. The MR findings were correlated with those obtained by the gold standard, standard VCUG.

RESULTS

Of the 44 kidney-ureter units, 20 were refluxing on MRVCUG and 21 were refluxing on standard VCUG. There were one false-positive and two false-negative units. MRVCUG was 90% sensitive with a specificity of 96% for detecting VURs that were calculated based on kidney-ureter units. Two false-negative units were found in mild cases (grade I and II). For the units of grade III, IV, and V (high-grade reflux), MRVCUG detected all of the refluxing renal collecting systems.

CONCLUSION

MRVCUG can demonstrate high-grade reflux without ionizing radiation or catheterization.

Estudo do jato urinário intravesical com Doppler colorido em pacientes com e sem refluxo vesicoureteral

OBJETIVO: O presente estudo teve como objetivo comparar os achados da uretrocistografia miccional com o ultra-som Doppler duplex colorido, em pacientes com suspeita de refluxo vesicoureteral. MATERIAIS E MÉTODOS: A pesquisa foi realizada através do estudo dos ângulos dos jatos urinários intravesicais, nos planos axial e longitudinal. Foi analisada, também, a distância (em centímetros) entre os meatos ureterais. RESULTADOS: Do total de 32 pacientes estudados (com média de idade de 5 anos e 2 meses), 18 pacientes apresentaram refluxo vesicoureteral (10 com refluxo unilateral, sendo 4 no lado direito e 6 no lado esquerdo, e 8 com refluxo bilateral) e 14 pacientes não apresentaram refluxo. Os valores angulares dos jatos urinários intravesicais e as distâncias entre os meatos ureterais foram obtidos para todos os pacientes e foram calculados a média, o desvio-padrão e o coeficiente de variação. CONCLUSÃO: Os dados evidenciaram tendência de que a lateralização do meato ureteral seja sinal de predisposição ao refluxo vesicoureteral. A análise estatística não-paramétrica de Mann-Whitney não evidenciou diferenças significativas (p > 0,05) entre os grupos (ângulos de inclinação dos jatos urinários intravesicais e distância entre os meatos ureterais).

Current status of vesicoureteral reflux diagnosis

In children, diagnostic imaging for vesicoureteral reflux (VUR) encompasses both radiologic and sonographic modalities. The former comprises voiding cystourethrography (VCUG), the most widespread method for examination for reflux, and radionuclide cystography (RNC). In RNC the radiation exposure is significantly less than in VCUG with continuous fluoroscopy, but the anatomic details depicted are much inferior. With the introduction of pulsed fluoroscopy, the radiation exposure of VCUG has been markedly curtailed. VCUG is the first imaging choice for the urethra. The sonographic diagnosis of VUR with the intravesical administration of an ultrasound (US) contrast agent-voiding urosonography (VUS)-is being used increasingly in the routine diagnostic imaging work-up of reflux. Various sonographic reflux examination methods had been tried in the past. The real breakthrough came with the availability of stabilized US contrast media. Further impetus came with the introduction of harmonic US imaging. The recent release of a second generation US contrast medium promises to make a further positive impact on VUS. The diagnostic accuracy of contrast-enhanced VUS has been found to be comparable to radiologic methods. VUS is primarily performed in follow-up studies and as the primary reflux examination modality in girls.

Ultrasound screening for renal and urinary tract anomalies in healthy infants

BACKGROUND

Nearly 30% of childhood cases of chronic renal failure in Japan are attributed to congenital anomalies of the kidney and urinary tract (CAKUT), and the number is increasing. Urine screening at school facilitates early diagnosis and treatment of glomerulonephritis, but early screening for anomalies is currently not in practice. The authors evaluated the value of early abdominal ultrasonography screening in 1-month-old infants.

METHODS

The following characteristics of kidneys were assessed: presence versus absence, size, symmetry of size, position, separation of the central echo complex (CEC), abnormal echogenicity, and other abnormal findings. The bladder and ureter were checked for abnormalities in bladder shape and wall, as well as retrovesical ureteral dilation. Criteria for abnormalities included kidney length of <or=35 mm, or >or=60 mm; a difference in length of left and right kidneys of 10 mm or more; and CEC separation of Society for Fetal Urology (SFU) grade 2 or higher.

RESULTS

Beginning in April 1994 and continuing until September 2001, screening of 5700 1-month-old infants yielded 198 positive cases (3.5%) of CAKUT. Most frequent was abnormal CEC separation (approximately 60% of all abnormalities), followed by abnormal renal size or size asymmetry (30%). Further investigation yielded a specific diagnosis in 32 cases (0.6%) of all subjects. Most prevalent was obstructive uropathy (15 cases); 8 children underwent surgery. Small kidneys and vesicoureteral reflux were next in frequency.

CONCLUSIONS

Ultrasonograpy was effective for early detection of renal and urinary tract anomalies. Ultrasound screening in early infancy may permit early treatment, that can prevent renal dysfunction.

Mass screening for early detection of congenital kidney and urinary tract abnormalities in infancy

BACKGROUND

Recent widespread use of ultrasound has led to new efforts at screening for congenital kidney and urinary tract abnormalities. However, a standard screening methodology, criteria defining abnormalities, and follow-up procedures remain to be established. In order to establish screening criteria for these abnormalities, we performed a preliminary study in 800 1-month-old infants using provisional methods and criteria.

METHODS

Based on the results of preliminary study, we screened 2700 1-month-old infants in a prospective study using the criteria of renal size (longitudinal diameter <or=35 mm or >or=60 mm, or a difference between sides of >or=10 mm), and of pelvic dilatation (Society for Fetal Urology [SFU] grade 2 or higher) as positive at the first ultrasound screening. We used the SFU grading system instead of anteroposterior pelvic diameter measurements for pelvic dilatation.

RESULTS

One hundred and twelve (4.1%) of the 2700 infants had abnormalities at the first ultrasound screening, while 18 (0.67%) had congenital kidney and urinary tract abnormalities on further examination. Use of the SFU grading system enabled us to reduce the false-positive rate at first screening, while maintaining a high diagnostic rate. The abnormalities consisted of ureteropelvic junction obstruction in seven infants, megaureter in two, hypoplastic kidney in four, vesicoureteral reflux in six (three were accompanied by hypoplastic kidneys or multicystic dysplastic kidney), multicystic dysplastic kidney in one, and horseshoe kidney in one.

CONCLUSION

These results indicate that our screening methods and criteria are useful variables for detecting congenital kidney and urinary tract abnormalities.

The ureteric jet doppler waveform as an indicator of vesicoureteric sphincter function in adults and children. An observational study

The nature of the action of the vesicoureteric junction (VUJ) in humans is still controversial. We were interested in the reasons why the jet consists of several peaks. We hypothesised that the modification of the jet into a variable number of peaks is the result of an active sphincter mechanism at the VUJ. A total of 1,010 subjects of all ages and both genders were recruited into this study. The Doppler waveform of the jet was recorded bilaterally. We could identify six basic patterns of ureteric jet according to the number of peaks: monophasic, biphasic, triphasic, polyphasic (four or more peaks), square and continuous. By analysing the duration, maximum peak velocity and initial slope of the first four patterns, a mechanism of action of an active VUJ sphincter could be postulated. Furthermore, the basic patterns could be assigned to three modes of ureteric actions: the square and continuous are only seen during diuretic stress; the biphasic, triphasic and polyphasic patterns are variations of the adult physiological steady-state mode, and the monophasic is distinctly different and represents the immature mode.

Possible use of ultrasound estimated bladder weight in evaluating vesicoureteral reflux in children

The present study was designed to reveal the possible use of ultrasound estimated bladder weight (UEBW) in evaluating vesicoureteral reflux (VUR) in children in terms of possible implication of bladder hypertrophy in VUR. In 27 children with VUR, UEBW was measured by transabdominal ultrasound. The UEBW in an individual patient was evaluated quantitatively using the percent deviation from age matched UEBW. There was a significant difference noted in the percent deviation from age-matched UEBW between patients (n = 17) with primary VUR and those (n = 10) with secondary VUR (p <.05). When analyzed together in 27 patients, a significant positive correlation (p <.05) was recognized between the percent deviation from age-matched UEBW and VUR grade. This was also the case in ten patients with secondary VUR (p <.01), but not for 17 patients with primary VUR. The measurement of UEBW might be of clinical use in evaluating the pathogenesis as well as the severity of VUR in children.

Vesicoureteral reflux: diagnosis and grading with echo-enhanced cystosonography versus voiding cystourethrography

PURPOSE

To evaluate the usefulness of echo-enhanced cystosonography compared with voiding cystourethrography (VCUG) for detecting and grading vesicoureteral reflux (VUR).

MATERIALS AND METHODS

Two hundred sixteen pediatric patients underwent cystosonography enhanced with SH U 508A, a galactose-based echo-enhancing agent. Sonograms of the kidneys and bladder were obtained before filling, during bladder filling, and during voiding. This examination was followed immediately with VCUG. Each kidney or portion of a kidney with its own complete collecting system was considered separately, for a total of 440 kidney units.

RESULTS

VUR was detected in 123 kidney units at cystosonography and in 104 at VCUG. In 401 kidney units, there was concordance between results at cystosonography and at VCUG regarding the presence or absence of VUR. Ninety-four kidney units showed VUR with both methods. Seventy-seven of the 94 refluxing units were depicted with the same grade of VUR with both modalities, and in 17 the VUR grade was greater at cystosonography than at VCUG. Twenty-nine of the 94 units showed VUR at only cystosonography, and 10 units at only VCUG. The McNemar test showed that cystosonography depicted a significantly (P = .003) higher number of units with VUR. By patient, VUR was depicted with both studies in 67 and with only one study in 25. VUR was seen at only cystosonography in 16 patients and at only VCUG in nine. The McNemar test for patients showed no significant difference between the two tests in detection of VUR.

CONCLUSION

Cystosonography with SH U 508A appears comparable to VCUG in the depiction of VUR.

Doppler visualization of ureteric jets in unilateral hydronephrosis in children and adolescents

OBJECTIVE

to evaluate Doppler visualization of ureteric jets in the assessment of unilateral kidney collecting system dilatation in children and adolescents.

METHODS AND PATIENTS

color Doppler ultrasonography was performed in 27 patients with hydronephrosis (11 female, 16 male, age range 3-21 years, mean age 10.5+/-4.4). Nine had acute obstruction due to ureteral calculus, seven had obstructive hydronephrosis due to uretero-pelvic junction (UPJ) stenosis, and 11 had non-obstructive hydronephrosis. Doppler was also performed in 32 healthy children (15 boys and 17 girls, age 2-17 years, mean age 7.8+/-3.9), who represented the control group.

RESULTS

in the control group jets were visible in 57 out of 64 ureteric units (89%). The mean frequency of jets in healthy children was 4.1 jets per min. In all children with hydronephrosis, jets were visible in 25 out of 27 normal ureteric units (92.6%), and their mean frequency was 4.5 jets per min. In children with acute unilateral colic, ureteric jets were completely absent in eight of nine patients (89%). In children with obstructive hydronephrosis, due to UPJ stenosis, jets were absent in five out of seven patients (71.4%), and in children with non-obstructive hydronephrosis jets were absent in three out of eleven patients (27.3%). When jets are visible, their frequencies are much lower on the obstructed side as compared with normal side, while in cases of nonobstructive dilatation frequency of jets is similar on both sides.

CONCLUSION

absence of jets in patients with acute obstruction due to ureteral calculus, strongly correlates with high-grade obstruction. In children with UPJ stenosis, presence of ureteric jet does not exclude significant obstruction, but the frequency of jets on the obstructed side is much lower as compared with the unaffected side. When there is absence of jet from the dilated side or significant asymmetry in jet frequency, hydronephrosis is likely to be obstructive.

Evaluation and validation of ureteric jet index by glomerular filtration rate

RATIONALE AND OBJECTIVES

Ureteric jet index (UJI), a newly developed technique derived from color Doppler ultrasonography, may hold promise in evaluating renal function because of its ability to evaluate individual renal function and the use of nonionizing radiation. To assess the usefulness of UJI, the authors in this study analyzed the relation between UJI and the glomerular filtration rate (GFR).

METHODS

Fifteen adult patients with a wide range of renal function were included in this study. Subjects were well hydrated before color Doppler ultrasonography examinations. The UJI formula was: Vmean (average jet velocity) x D (jet duration) x F (jet frequency). GFR was calculated by the radionuclide method. Correlations between UJI, serum creatinine, and GFR were analyzed.

RESULTS

Ureteric jet index had only a fair correlation with GFR. The coefficient of correlation value was 0.61, and the standard error of estimate of GFR was 17.9 mL/min.

CONCLUSIONS

With the measurement of UJI, color Doppler ultrasound can provide both structural images and individual renal function information. It could substitute for a renal scan in determining individual renal function when a radionuclide examination is unavailable. Even if a renal scan were available, UJI can play a valuable role in the ultrasound examination of patients with suspected impaired renal function, providing further assessment of individual renal function.

Color flow Doppler sonography: a reliable alternative to voiding cystourethrogram in the diagnosis of vesicoureteral reflux in children

OBJECTIVES

In children with urinary tract infection, the incidence of vesicoureteral reflux (VUR) is nearly 30% to 40%. The standard for the diagnosis of VUR is voiding cystourethrography (VCUG). This study assessed the role of color flow Doppler sonography (CFDS) in the diagnosis of VUR and ureteral jets.

METHODS

CFDS imaging was performed in 36 patients aged 6 months to 13 years during a 4-year period. All patients underwent CFDS and VCUG within 24 to 48 hours, but the findings of the VCUG were not reported to the sonologist. The ultrasound examinations were done using a color Doppler real-time machine. Representative images of the bladder events were recorded with a multiformat camera and on VHS videotape.

RESULTS

The duration of the Doppler signal varied from 0.4 to 7.5 seconds. In 31 (86.1%) of 36 patients, the results of CFDS correlated well with VCUG findings. There were three false-negative and two false-positive results in the present study. Six patients underwent reimplantation during the course of their treatment. CFDS was used as a follow-up modality at the end of 6 months, and the results correlated well with standard VCUG in 4 of these patients. In the remaining 2 patients, only CFDS was performed and correlation with VCUG was not possible. VCUG was considered the reference standard in assessing the sensitivity of CFDS.

CONCLUSIONS

CFDS of the bladder during the filling and micturating phases is a reliable and sensitive modality for identifying VUR and demonstrating ureteral jets. CFDS nullifies the danger of exposure to ionizing radiation and avoids the unpleasant catheterization many of these children fear.

Technical report: urinary tract infections in febrile infants and young children. The Urinary Tract Subcommittee of the American Academy of Pediatrics Committee on Quality Improvement

OVERVIEW

The Urinary Tract Subcommittee of the American Academy of Pediatrics Committee on Quality Improvement has analyzed alternative strategies for the diagnosis and management of urinary tract infection (UTI) in children. The target population is limited to children between 2 months and 2 years of age who are examined because of fever without an obvious cause. Diagnosis and management of UTI in this group are especially challenging for these three reasons: 1) the manifestation of UTI tends to be nonspecific, and cases may be missed easily; 2) clean voided midstream urine specimens rarely can be obtained, leaving only urine collection methods that are invasive (transurethral catheterization or bladder tap) or result in nonspecific test results (bag urine); and 3) a substantial number of infants with UTI also may have structural or functional abnormalities of the urinary tract that put them at risk for ongoing renal damage, hypertension, and end-stage renal disease (ESRD).

METHODS

To examine alternative management strategies for UTI in infants, a conceptual model of the steps in diagnosis and management of UTI was developed. The model was expanded into a decision tree. Probabilities for branch points in the decision tree were obtained by review of the literature on childhood UTI. Data were extracted on standardized forms. Cost data were obtained by literature review and from hospital billing data. The data were collated into evidence tables. Analysis of the decision tree was used to produce risk tables and incremental cost-effectiveness ratios for alternative strategies.

RESULTS

Based on the results of this analysis and, when necessary, consensus opinion, the Committee developed recommendations for the management of UTI in this population. This document provides the evidence the Subcommittee used in the development of its recommendations.

CONCLUSIONS

The Subcommittee agreed that the objective of the practice parameter would be to minimize the risk of chronic renal damage within reasonable economic constraints. Steps involved in achieving these objectives are: 1) identifying UTI; 2) short-term treatment of UTI; and 3) evaluation for urinary tract abnormalities.

Reflux in young patients: comparison of voiding US of the bladder and retrovesical space with echo enhancement versus voiding cystourethrography for diagnosis

PURPOSE

To compare the usefulness of voiding US of the bladder and retrovesical space with echo enhancement with that of voiding cystourethrography (VCUG) for diagnosis of vesicoureteral reflux (VUR) and to assess patient tolerance of the echo-enhancing agent.

MATERIALS AND METHODS

One hundred eighty-eight patients (aged 5 days to 20 years) referred for investigation of VUR underwent voiding US with echo enhancement, which was followed by VCUG in 110 patients (226 kidney-ureter units). After US of the renal tract, the bladder was filled with normal saline solution. Then SU U 508 A, a galactose-based, microbubble-containing echo-enhancing agent, was administered. Reflux was diagnosed when microbubbles appeared in the ureter or pelvicalyceal system.

RESULTS

VUR was detected in 80 of the units with one (n = 18) or both (n = 62) methods. All grades of reflux were identified. In 15 units, reflux diagnosed at voiding US was not observed at VCUG; the reverse was true in three units. In 208 (92%) of the 226 kidney-ureter units, there was concordance between the two methods regarding the diagnosis or exclusion of VUR. The echo-enhancing agent was well tolerated.

CONCLUSION

SH U 508 A enhanced voiding US is as good as VCUG in the detection or exclusion of VUR and thus will make it possible to reduce the number of children having to be exposed to ionizing radiation.

The ureteric jet index: a novel measure of divided renal function

The aim of this study was to evaluate an index of divided renal function based on the quantification of the ureteric jets seen on colour Doppler ultrasound of the bladder. Thirty-one patients attending for scintigraphic renography underwent colour Doppler ultrasound with video recording for 5 min. Divided renal function was calculated as the proportion of jets from the right-sided orifice ('jet index'). This was compared with the corresponding 'scintigraphic index' found using Patlak-Rutland graphical analysis. Absolute discrepancies were calculated. Twenty-eight of thirty-one (90%) of studies were diagnostic for the calculation of jet indices. The mean jet index was 52% (n=28, SEM=5.8%) compared to a mean scintigraphic index of 54% (n = 28, SEM = 4.0%). The two scores were correlated, with a correlation coefficient of 0.72 and the median absolute difference between the two scores was 7.7%. Forty-three per cent (12/28) of subjects had discrepancies in the two scores of 5% or less. The score differences, however, showed a highly skewed distribution with 32% (9/28) subjects showing discrepancies over 20%. This discordant group (> 20% difference) included three patients with functional pelviureteric obstruction, one with a pelvic mass and one with an underfilled bladder. Two patients with very poor quality jets had impaired renal function. In one case, the index improved after angioplasty for renal artery stenosis. This simple test is a useful adjunct to urinary tract ultrasound but should be interpreted alongside evidence of renal obstruction, and complements rather than replaces existing tests.

Color Doppler ultrasound for evaluation of collagen implants after endoscopic injection treatment of refluxing ureters in children

To determine whether color Doppler ultrasonography (CDUS) would add to the understanding of the bladder wall after endoscopic subureteral collagen injection (SCIN), 25 patients were studied with CDUS. The kidney length and echogenicity, the volume of the collagen, the mean length of the urinary jet, the longitudinal and transverse angles, and the distance between the origin of the jet and the midline of the bladder were measured 1 day, 1 month, and 3 months after SCIN and compared to the results of micturating cystourethrograms (MCUs) performed 3 months after SCIN. The collagen was hyperechogenic compared to the bladder wall at the time of injection, and was isoechogenic 1 and 3 months after SCIN. CDUS showed the relationship between the injected collagen and the position of the ureteral orifice. The measurements of jet length, angle, and distance of the ureteral orifice from the midline did not correlate with vesicoureteral reflux assessed by MCU. Although CDUS may demonstrate the location, the size of the injected collagen implant, and its relationship to the ureteral orifice, it is as yet unable to predict vesicoureteral reflux after SCIN.

Detection of low-grade vesicoureteral reflux in children by color Doppler imaging mode

Vesicoureteral reflux (VUR) is common in children with urinary tract infections (UTI) and may result in renal scarring or reflux nephropathy. To date, the primary diagnostic tool has been voiding cystourethrography (VCUG). A new technique for evaluation of grade 1 and 2 VUR is described using color Doppler imaging-mode cystography (CDIMC): 77 children, aged 7 months to 14 years, were examined for VUR by CDIMC and standard VCUG. According to the established reflux sonography (US) using a real-time mode, all patients selected for this study had a normal urinary tract on conventional gray-scale US. We studied 154 ureters, and a total of 31 were found to be refluxing on CDIMC and 30 on VCUG. A positive sonogram was defined as visualization of Doppler signals from the bladder to the ureter during the course of bladder filling. Taking VCUG as the gold standard, we had ten false-positive findings. The false-positive rate of 18.5% may have been due to the shorter observation time of fluoroscopy. Comparison of the two methods shows CDIMC to be 70% sensitive with a specificity of 92% in the detection of VUR grade 1 and 2. To evaluate the incidence of asymptomatic low-grade VUR in a non-infected population, a second series of 38 children (19 males, 19 females) aged 3 to 15 years (mean 8.8 years) with normal urologic status and urine cultures were studied by color Doppler imaging mode (CDIM) for detection of asymptomatic low-grade VUR. Four children were found to have a unilateral refluxing ureter. The incidence of VUR in children with a normal urinary tract and no prior UTI was 10.5%. In conclusion, CDIMC can be used as a possible alternative to standard VCUG for the screening and follow-up of low-grade VUR. In addition, our study indicates that asymptomatic grade 1 and 2 reflux might be a physiological condition.

Ureteric jet examination by color Doppler ultrasound versus IVP for the assessment of ureteric patency following pelvic surgery--a pilot study

During the study period 228 women underwent major gynecological surgery in our department. Of these, 25 were selected for the study because of suspected post-operative ureteric obstruction. Post-operatively, both intravenous pyelography (IVP) and ureteric jet examination by the means of color Doppler ultrasound were performed in the study group. The aims were to exclude iatrogenic ureteric occlusion and to test the reliability of ureteric jet examination with ultrasound, as compared with IVP, as a diagnostic test for ureteric obstruction. In 19 patients both IVP and jet examination were normal. In the remaining six patients, jet was negative either uni- or bi-laterally. Of these six, only two obstructions were diagnosed using IVP. This test was associated with a positive predictive value of 33.3%, negative predictive value of 100%, sensitivity of 100%, specificity of 88.6%, false negative of 0% and a false positive of 17.4%. It is concluded that the results suggest that color Doppler ultrasound may be a good screening test for ureteric occlusion following pelvic surgery. Whenever a jet test is negative, further evaluation by IVP is required.

Reflux nephropathy: the glomerular lesion and progression of renal failure

Reflux nephropathy is the cause of 5%-10% of dialysed end-stage renal failure. Once scarring has occurred, the prognosis depends on the severity of initial damage and the presence of proteinuria, which reflects the development of glomerulosclerosis. It is independent of ongoing reflux or infection. Histological appearances highly suggestive of reflux nephropathy can occur in radiologically normal kidneys. Duplex Doppler scans of ureteric orifices suggest these patients may have lateral insertion, suggesting past reflux. Glomerular hypertrophy correlates well with reduced renal function and severe renal scarring, but poorly with focal and segmental glomerulosclerosis, which correlates with proteinuria. Increasing attention is being paid to the tubulo-interstitium and the relationships between the cellular infiltrates (mainly T4 cells) and glomerular, tubular and vascular damage. Control of hypertension, hyperphosphataemia and a low-protein diet are the only currently widely accepted treatments for slowing progression.

Correlation of ultrasound and renal scintigraphy in children with unilateral hydronephrosis in primary workup

Ultrasound accurately detects hydronephrosis in infants and children, while nuclear medicine techniques quantify relative renal function in addition to characterizing the urodynamic relevance of hydronephrosis. This prospective study was undertaken to examine the relationship between ultrasound morphological findings and relative renal function, quantified with dynamic 99mtechnetium mercaptotriacetylglycine imaging, in the initial diagnostic workup of children with unilateral hydronephrosis. The ultrasound grade of hydronephrosis and relative renal function ipsilateral to the hydronephrosis were inversely related, indicating that with more severe hydronephrosis ultrasound fails to estimate the potential reduction of relative kidney function. Because renal function is not necessarily affected by hydronephrosis, renal scintigraphy is indicated to assess the functional status of hydronephrotic kidneys.

The low frequency of reflux in Jamaican children

Fifty consecutive micturating cystourethrograms (MCUG) performed at the UHWI between June 1989 and December 1991 were reviewed. There were forty boys and ten girls. Infants under the age of one year accounted for 58%. Urinary tract infection was the commonest presenting feature (72%), voiding difficulties (10%) and associated malformations (14%) were the other reasons for doing the MCUG. Only 10% of the children revealed vesico-ureteral reflux (VUR) which supports the view that reflux is less common in the noncaucasian population. In our population, the yield from MCUG is low. However, when detected, the reflux was of significant degree as to warrant active therapy. All but one of the VU refluxes diagnosed by MCUG had ultrasonographic abnormalities. Black children with single urinary infections have a low likelihood of VUR. A clear history of pyelonephritis and abnormalities on ultrasound or radionuclide cystogram may be used as criteria to select those in whom MCUG will be useful.

Ultrasound screening of newborn urinary tract

A non-invasive method to screen newborn babies for ureteric reflux might allow the possibility of appropriate action to prevent reflux nephropathy. We have tested the sensitivity of ultrasound screening of the urinary tract. 1061 unselected newborn infants born during 1986 were examined by ultrasound and the findings were recorded on videotape. Babies with dilated renal collecting systems underwent further investigations (micturating cystourethrography, intravenous urography, or radioisotope study). With these methods, 11 children were found to have renal disorders. A postal follow-up survey was carried out when the children were 3 years old. 657 (62%) families responded. We searched for non-responders among children born in 1986 who had subsequently had a renal radioisotope investigation: 5 non-responders were found among these children. Of the total, 24 children had had a urinary-tract infection: 3 more children with ureteric reflux were found; their neonatal ultrasound scans had suggested no abnormality. Thus, more than half the children of this cohort in whom hydronephrosis or ureteric reflux developed had only slight dilatation (less than 5 mm) on the neonatal scan. On review of the original videotapes there was no difference in internal dimension between left and right kidneys: the internal dimension was 5 mm or less in both kidneys in 96.3% of babies and 4 mm or less in 93.3%. Routine renal ultrasound scanning of newborn babies is of no value in detecting those who may have ureteric reflux: the number of other renal abnormalities likely to be detected is small.

Evaluating Ureteral Jets with Color Doppler in Adults

Color Doppler was used to evaluate urine jets within the urinary bladder in adult patients. In normally hydrated patients, urine was noted to jet from both sides within an interval of a few seconds. Future use of color Doppler in evaluating renal function and urinary tract pathology by visualizing urine output may be possible.

RARE-MR-urography in the diagnosis of upper urinary tract abnormalities in children

RARE-MR-urography (Rapid Acquisition with Relaxation Enhancement) is a fast MR imaging technique (6.4 s/acquisition) that selectively depicts fluid by heavy T2-weighting. From 9/1989 to 11/1990, RARE-MR urograms were prospectively evaluated in the diagnosis of upper urinary tract abnormalities in 55 children. The method is performed in several planes and combined with a coronal, T1-weighted spin-echo sequence. Forty out of 42 kidneys with dilated renal pelvis, and 21 out of 24 dilated ureters were identified, only the mildly dilated ones were missed. Even in non-functioning kidneys the urinary tract was clearly depicted by RARE-MR-urography. However, no differentiation could be made with this technique between vesicoureteral reflux and non-refluxing dilatation of ureter and/or renal pelvis. All 19 pelviureteric obstructions and all eight renal duplications with a dilated segment were identified. RARE-MR-urography is a new tool for diagnosing urinary tract abnormalities in children without having to employ ionizing radiation, contrast media, or general anesthesia. A dilated urinary tract can be shown in one image displaying the entire urinary system, similar to excretory urography. The technique is presently not able to provide the information of voiding cystourethrography or renal scintigraphy, nor is it as easy to perform as ultrasound. However, in certain cases it may replace excretory urography.