Can careful ultrasound examination of the urinary tract exclude vesicoureteric reflux in the neonate?

Urinary carbohydrate antigen 19-9 level as a biomarker in children with acute pyelonephritis

Early and prompt diagnosis of pyelonephritis is of great importance in children. The aim of this study is to evaluate the diagnostic accuracy of urinary carbohydrate antigen 19-9 (CA19-9) levels for predicting acute pyelonephritis (APN) in children with urinary tract infection (UTI). Patients were allocated into two groups of APN and acute cystitis according to their diagnosis. Urine samples of all patients were collected. Also, complete history was taken, and physical examination, kidney and bladder ultrasonography, ^99mTc-dimercaptosuccinic acid renal cortical scintigraphy, and urine analysis and culture were performed. Urinary CA19-9 was measured by an electrochemiluminescence enzyme immunometric kit. In addition, CA19-9 levels were measured in the APN group 2 weeks and 3 months later. A total of 100 children were included in this study (mean age 46 ± 31 months, 16 males and 84 females). CA19-9 levels were significantly greater in the APN group than acute cystitis group (510 ± 328 vs. 18.7 ± 18.6 U/ml, P < 0.001). During follow-up periods of the APN group, CA19-9 levels decreased to 180 ± 124 U/ml after 2 weeks (P < 0.001) and 30 ± 23 U/ml after 3 months (P < 0.001). Urinary CA-19-9 had 95.3% sensitivity and 80% specificity for the diagnosis of APN. The area under the curve value of CA19-9 was 0.904 (95% CI 0.831-0.977).Conclusion: Urinary CA19-9 level can be used as a reliable biomarker for early detection of APN prior to urine culture confirmation in children with UTI. What is known: • Early and prompt diagnosis of pyelonephritis is necessary in children to prevent renal damage. • Acute pyelonephritis can present with vague and nonspecific symptoms in infants and children. What is new: • Urinary carbohydrate antigen 19-9 is a reliable biomarker for early detection of acute pyelonephritis prior to urine culture confirmation. • Urinary carbohydrate antigen 19-9 has 95.3% sensitivity and 80% specificity for diagnosis of acute pyelonephritis.

Clinical Outcome of Children With Antenatally Diagnosed Hydronephrosis

Fetal renal pelvis dilation is a common condition, which is observed in 1-4. 5% of pregnancies. In many cases, this finding resolves spontaneously. However, sometimes it may be a signal of significant urinary tract pathologies. The main abnormalities found after birth are uretero-pelvic junction stenosis, primary vesicoureteral reflux, megaureter, duplex kidneys, and posterior urethral valves, with uretero-pelvic junction stenosis and primary vesicoureteral reflux accounting for most of the cases. Diagnosis, management, and prognosis at short and longer term of these conditions will be reviewed in this article.

D-dimer as a marker of acute pyelonephritis in infants younger than 24 months with urinary tract infection

BACKGROUND

D-dimer, as well as other biomarkers related to coagulation, is significantly increased during severe bacterial infection and sepsis. The aim of this study was to evaluate the usefulness of serum D-dimer as a biological marker in diagnosing acute pyelonephritis (APN) and in predicting vesicoureteric reflux (VUR) in infants with urinary tract infection (UTI).

METHODS

We retrospectively analyzed the data of 177 young infants (<2 years) with febrile UTI between 2005 and 2014, grouped as APN and lower UTI groups. Conventional inflammatory markers (white blood cell count (WBC), erythrocyte sedimentation rates (ESR), C-reactive protein (CRP)), and D-dimer were measured.

RESULTS

The WBC counts (P = 0.002), ESR (P < 0.0001), CRP (P < 0.0001), D-dimer levels (P = 0.006) and the presence of VUR (P < 0.0001) were significantly higher in the APN group than in the lower UTI group. Multiple logistic regression analyses showed that D-dimer (odds ratio [OR]:1.003, 95% CI: 1.001-1.006, P = 0.002) was an independent predictive factor for VUR in young children with UTI. The area under the curve (AUC) value from the receiver operating characteristic (ROC) curve of D-dimer (0.621, P = 0.046, 95% CI: 0.499-0.743) for prediction of VUR was higher than other inflammatory markers, but was inferior to CRP in predicting APN.

CONCLUSIONS

Our results demonstrate that D-dimer can be used as an inflammatory marker in infants with febrile UTI in addition to other inflammatory markers.

Avoidance of voiding cystourethrography in infants younger than 3 months with Escherichia coli urinary tract infection and normal renal ultrasound

BACKGROUND AND OBJECTIVE

Urinary tract infection (UTI) represents the most common bacterial infection in infants, and its prevalence increases with the presence of high-grade vesicoureteral reflux (VUR). However, voiding cystourethrography (VCUG) is invasive, and its indication in infants <3 months is not yet defined. This study aims to investigate, in infants aged 0-3 months, if the presence of Escherichia coli versus non-E. coli bacteria and/or normal or abnormal renal ultrasound (US) could avoid the use of VCUG.

METHOD

One hundred and twenty-two infants with a first febrile UTI were enrolled. High-grade VUR was defined by the presence of VUR grade ≥III. The presence of high-grade VUR was recorded using VCUG, and correlated with the presence of E. coli/non-E. coli UTI and with the presence of normal/abnormal renal US. The Bayes theorem was used to calculate pretest and post-test probability.

RESULTS

The probability of high-grade VUR was 3% in the presence of urinary E. coli infection. Adding a normal renal US finding decreased this probability to 1%. However, in the presence of non-E. coli bacteria, the probability of high-grade VUR was 26%, and adding an abnormal US finding increased further this probability to 55%.

CONCLUSIONS

In infants aged 0-3 months with a first febrile UTI, the presence of E. coli and normal renal US findings allow to safely avoid VCUG. Performing VCUG only in infants with UTI secondary to non-E. coli bacteria and/or abnormal US would save many unnecessary invasive procedures, limit radiation exposure, with a very low risk (<1%) of missing a high-grade VUR.

Role of Renal Ultrasonography in Predicting Vesicoureteral Reflux and Renal Scarring in Children Hospitalized with a First Febrile Urinary Tract Infection

BACKGROUND

This study was designed to examine the capability of renal ultrasonography (US) for predicting vesicoureteral reflux (VUR) and renal scarring (RS), and to assess, using initial US, the significant urologic abnormalities that impact on management of children hospitalized with a first febrile urinary tract infection (UTI).

METHODS

Hospitalized children aged ≤ 2 years with a first febrile UTI were prospectively evaluated using imaging studies, including (99m)Tc dimercaptosuccinic acid (DMSA) scan, US, and voiding cystourethrography.

RESULTS

Of the 310 children analyzed (195 boys and 115 girls), 105 (33.9%) had abnormal US. Acute DMSA scans were abnormal in 194 children (62.6%), including 89 (45.9%) with concomitant abnormal US. There was VUR in 107 children (34.5%), including 79 (25.5%) with Grades III-V VUR. The sensitivity and negative predictive values of US were 52.3% and 75.1%, respectively, for Grades I-V VUR and 68.4% and 87.8%, respectively, for Grades III-V VUR. Eighty-five children (27.4%) had RS, including 55 (64.7%) with abnormal US. Of the 105 children with abnormal US, 33 (31.4%) needed subsequent management (surgical intervention, parental counseling, or follow up of renal function). Nephromegaly on initial US and Grades III-V VUR were risk factors of RS.

CONCLUSION

Abnormal US may carry a higher probability of Grades III-V VUR and RS, and can affect subsequent management in a significant number of children. Nephromegaly on initial US and Grades III-V VUR are strongly associated with an increased risk for RS. Thus, US should be performed on children after a first febrile UTI and children with normal US may not require voiding cystourethrography.

Postnatal Evaluation and Outcome of Prenatal Hydronephrosis

BACKGROUND

Prenatal hydronephrosis (PNH) is dilation in urinary collecting system and is the most frequent neonatal urinary tract abnormality with an incidence of 1% to 5% of all pregnancies. PNH is defined as anteroposterior diameter (APD) of renal pelvis ≥ 4 mm at gestational age (GA) of < 33 weeks and APD ≥ 7 mm at GA of ≥ 33 weeks to 2 months after birth. All patients need to be evaluated after birth by postnatal renal ultrasonography (US). In the vast majority of cases, watchful waiting is the only thing to do; others need medical or surgical therapy.

OBJECTIVES

There is a direct relationship between APD of renal pelvis and outcome of PNH. Therefore we were to find the best cutoff point APD of renal pelvis which leads to surgical outcome.

PATIENTS AND METHODS

In this retrospective cohort study we followed 200 patients 1 to 60 days old with diagnosis of PNH based on before or after birth ultrasonography; as a prenatal or postnatal detected, respectively. These patients were referred to the nephrology clinic in Zahedan Iran during 2011 to 2013. The first step of investigation was a postnatal renal US, by the same expert radiologist and classifying the patients into 3 groups; normal, mild/moderate and severe. The second step was to perform voiding cystourethrogram (VCUG) for mild/moderate to severe cases at 4 - 6 weeks of life. Tc-diethylene triamine-pentaacetic acid (DTPA) was the last step and for those with normal VCUG who did not show improvement in follow-up examination, US to evaluate obstruction and renal function. Finally all patients with mild/moderate to severe PNH received conservative therapy and surgery was preserved only for progressive cases, obstruction or renal function ≤35%. All patients' data and radiologic information was recorded in separate data forms, and then analyzed by SPSS (version 22).

RESULTS

200 screened PNH patients with male to female ratio 3.5:1 underwent first postnatal control US, of whom 65% had normal, 18% mild/moderate and 17% severe hydronephrosis. 167 patients had VCUG of whom 20.82% with VUR. 112 patients performed DTPA with following results: 50 patients had obstruction and 62 patients showed no obstructive finding. Finally 54% of 200 patients recovered by conservative therapy, 12.5% by surgery and remaining improved without any surgical intervention.

CONCLUSIONS

The best cutoff point of anteroposterior renal pelvis diameter that led to surgery was 15 mm, with sensitivity 88% and specificity 74%.

Comparison of procalcitonin and different guidelines for first febrile urinary tract infection in children by imaging

BACKGROUND

We examined the ability of a procalcitonin (PCT) protocol to detect vesicoureteral reflux (VUR) and renal scarring (RS), evaluated procedural costs and radiation burden, and compared four representative guidelines for children with their first febrile urinary tract infection (UTI).

METHODS

Children aged ≤2 years with their first febrile UTI who underwent renal ultrasonography (US), acute and late technetium-99m ((99m)Tc)-dimercaptosuccinic acid scan, and voiding cystourethrography were prospectively studied. The representative guidelines applied in a retrospective simulation included the American Academy of Pediatrics (AAP), National Institute of Clinical Excellence, top-down approach (TDA), and Italian Society of Pediatric Nephrology (ISPN). These were compared in terms of ability to detect abnormalities, procedural costs and radiation.

RESULTS

Of 278 children analyzed, 172 (61.9%) had acute pyelonephritis. There was VUR in 101 (36.3%) children, including 73 (26.3%) with grades III-V VUR. RS was identified in 75 (27.0%) children. To detect VUR, TDA and PCT had the highest sensitivity for grades I-V VUR (80.2%) and III-V VUR (94.5%), respectively, whereas AAP had the highest specificity for I-V VUR (77.4%) and III-V VUR (78.0%), respectively. TDA and PCT had the highest sensitivity (100%) for detecting RS. The highest cost and radiation dose was associated with TDA, whereas AAP had the least expenditure and radiation exposure. By multivariate analysis, PCT and VUR, especially grades III-V, were independent predictors of RS.

CONCLUSIONS

There is no perfect guideline for first febrile UTI children. The PCT protocol has good ability for detecting high-grade VUR and RS. If based on available imaging modalities and reducing cost and radiation burden, clinical suggestions in the AAP guidelines represent a considerable protocol.

The antenatally detected pelvi-ureteric junction stenosis: advances in renography and strategy of management

This review includes an analysis of new developments in the field of renography, the predictive factors suggesting the need for pyeloplasty in cases of pelvi-utereric stenosis detected antenatally and integration of the pelvi-ureteric junction stenosis within the framework of antenatally detected hydronephrosis.

Screening high-grade vesicoureteral reflux in young infants with a febrile urinary tract infection

BACKGROUND

The lack of good evidence for improved outcomes in children and young infants with febrile urinary tract infection (UTI) after aggressive treatment for vesicoureteral reflux (VUR) has raised doubts regarding the need for routine voiding cystourethrography (VCUG), and the appropriate imaging evaluation in these children remains controversial.

OBJECTIVES

This prospective study aimed to determine whether abnormalities found on acute dimercaptosuccinic acid (DMSA) scan and ultrasound (US) can help indicate the necessity of voiding cystourethrography (VCUG) in young infants.

METHODS

For 3.5 years, all infants younger than 3 months presenting with first febrile UTI were prospectively studied. All infants were hospitalized and investigated using US (<3 days after admission), DMSA scan (<5 days after admission), and VCUG (7-10 days after antibiotic treatment) after diagnosis. The association among findings of US, DMSA scan, and VCUG were evaluated.

RESULTS

From 220 infants, there were abnormal results in 136 (61.8%) US and in 111 (50.5%) DMSA scans. By US, ten infants (4.5%) with abscess or structural abnormalities other than VUR were diagnosed. High-grade (III-V) VUR was present in 39 patients (17.7%). The sensitivities for high-grade VUR of renal US alone (76.9%) or DMSA scan alone (82.1%) were not as good as that of the "OR rule" strategy, which had 92.3% sensitivity and 94.3% negative predictive value.

CONCLUSIONS

To screen high-grade VUR in young infants with febrile UTI, US and acute DMSA scan could be performed first. VCUG is only indicated when abnormalities are apparent on either US or DMSA scan or both.

Clinical spectrum of antenatally detected urinary tract abnormalities with respect to hydronephrosis at postnatal ultrasound scan

AIM

The purpose of this study was to compare the outcome of infants having antenatally detected urinary tract abnormalities (AUTAs) with respect to the presence of hydronephrosis in postnatal ultrasonography (US) examination.

PATIENTS AND METHODS

Between January 1999 and October 2009, 256 infants diagnosed with AUTAs were prospectively followed. Infants were divided into two groups according to the presence of hydronephrosis in postnatal US examination: Group 1, infants with hydronephrosis; Group 2, infants without hydronephrosis (including renal cyst, agenesis, ectopic kidney). The events of interest were the presence and diagnoses of uropathy, AUTA resolution, urinary tract infection (UTI), development of renal parenchymal defects (RPDs)--focal or global scarring, dysplasia--, acute kidney injury (AKI) and chronic kidney disease (CKD), and the need for surgery and dialysis treatment.

RESULTS

The most commonly detected underlying abnormalities were ureteropelvic junction obstruction (44.8 %), vesicoureteral reflux (VUR) (30.0 %) and megaureter (9.5 %) in patients with postnatal hydronephrosis. On the other hand, multicystic dysplastic kidney (43.5 %), renal agenesis (19.4 %) and VUR (19.4 %) were mostly encountered abnormalities in patients without postnatal hydronephrosis. RPDs were significantly more common among patients with postnatal hydronephrosis compared to those without hydronephrosis (37 vs. 21 %, P = 0.02). The incidence of UTI and VUR was higher in infants with postnatal hydronephrosis than in infants without hydronephrosis. There was no statistically significant difference in terms of the development of AKI and CKD and the need for surgery and dialysis treatment between patients with hydronephrosis and those without hydronephrosis.

CONCLUSION

Infants with AUTAs should be investigated postnatally. The findings from this study will help to identify the natural history and outcome of infants with AUTAs according to the postnatal US parameters.

The necessity of voiding cystourethrography in children with prenatally diagnosed hydronephrosis

The postnatal persistence of fetal hydronephrosis requires further evaluation to establish whether pathological abnormalities are present. This study determined the necessity for voiding cystourethrography (VCUG) to identify vesicoureteral reflux (VUR) in children (n = 195) with prenatally diagnosed hydronephrosis. Among the study population, the prevalence of VUR was 17.4% (24 males, 10 females). There was a poor correlation between the severity of hydronephrosis, ureteral dilatation, presence of bilateral hydronephrosis and presence of VUR. Except for the frequency of urinary tract infections and the presence of renal damage on (99m)Tc-dimercaptosuccinic acid scans, VCUG was the only reliable method for confirming VUR in this study. The diagnosis of VUR is important for the early detection of renal damage. Further information is needed to develop the optimal approach to the evaluation of prenatal hydronephrosis, with reliable parameters that avoid invasive procedures such as VCUG.

Characteristics of first urinary tract infection with fever in children: a prospective clinical and imaging study

BACKGROUND

Our objective is to provide the clinical characteristics, uropathogen frequencies, and antimicrobial resistance rates of first urinary tract infection (UTI) diagnosed in febrile Belgian children. The ability of noninvasive ultrasound to detect renal abnormalities and vesicoureteral reflux (VUR) in these patients was also assessed.

METHODS

We prospectively followed (median, 20 months) 209 children treated for first febrile UTI. Renal ultrasound (US) and voiding cystourethrography examinations were performed in all patients.

RESULTS

Among these children, 63% were females and 37% were males, and 75% of them had their first UTI before the age of 2 years. The most common causative agent was Escherichia coli (91% of cases) with high rate resistance to ampicillin (58%) and trimethoprim/sulfamethoxazole (38%). Of these children, 25% had evidence of VUR (15 boys and 38 girls). VUR was of low grade in 85% of cases. The overall performance of renal US as a diagnostic test to detect significant uropathies excluding low-grade VUR was excellent; the sensitivity attained 97% and the specificity 94%.

CONCLUSION

Girls represent 63% of cases with first UTI. For 91% of UTIs, Escherichia coli is held responsible with a high rate of resistance to ampicillin and trimethoprim/sulfamethoxazole. US is an excellent screening tool that allows avoidance of unjustified voiding cystourethrography studies.

[Postnatal evaluation and management of fetal pyelectasis on prenatal ultrasound]

Fetal pyelectasis is the most frequently encountered anomaly on prenatal ultrasound. The ultrasound diagnostic criteria are well established: nature of dilated structures, degree of dilatation, ultrasound appearance of the kidneys, volume of amniotic fluid. Ultrasound can also determine if the anomaly is isolated or not, which is important for the management and prognosis of the pregnancy. Ultrasound is the initial postnatal study to evaluate the urinary tract. Further management will be based on suspected diagnosis. In cases of suspected vesico-ureteral reflux, VCUG is performed. In cases of obstructive uropathy or complex malformation (duplications), MRI is performed at 6 months of age to further define the anatomy of the urinary tract. Radionuclide renogram, performed in most cases, allows evaluation of split renal function. Follow-up ultrasound is important to monitor renal development, urinary tract dilatation and appearance of the renal parenchyma. Functional follow-up is assured by radionucline renography. This comprehensive follow-up is recommended to prevent complications and progressive loss of renal function.

Febrile urinary tract infections in 0- to 3-month-old infants: a prospective follow-up study

OBJECTIVE

To track the clinical evolution of febrile urinary tract infection (UTI) diagnosed in 0- to 3-month-old infants and characterize uropathogen frequencies, antimicrobial resistance rates, renal abnormalities, and differences in the sexes in this age group.

STUDY DESIGN

We observed prospectively 46 infants identified in a cohort of 209 children with first UTI diagnosed between July 2006 and July 2008 at the age of 0 to 3 months. Renal ultrasound scanning and voiding cystourethrography examinations were performed in all infants.

RESULTS

Infants < 3 months old represented 21% of all children with first UTI. Of these children, 26% were female and 74% were male. Escherichia coli was isolated in 88% of cases and had a high rate of resistance to ampicillin (71%) and to trimethoprim/sulfamethoxazole (47%); 21% of children had vesicoureteral reflux, which was of low-grade in 67% of cases, with spontaneous resolution before 2 years in all cases. In infants with normal ultrasound scanning results, a low-grade vesicoureteral reflux was subsequently found in 10% of cases.

CONCLUSION

Infants aged 0 to 3 months represent 21% of children treated for febrile UTI. Boys represent 74% of these cases. E coli is responsible for 88% of UTIs, with a high rate of resistance to antibiotics. When ultrasound scanning examination results are normal, the risk of missing a significant renal abnormality is expected to be extremely low.

Antenatal and postnatal ultrasound in the evaluation of the risk of vesicoureteral reflux

Antenatal hydronephrosis (ANH) is a frequent anomaly detected on fetal ultrasound scans. There is no consensus recommendation for the postnatal follow-up and/or the necessity to perform a voiding cystourethrography (VCUG) to diagnose vesicoureteral reflux (VUR). We conducted a cohort/non-randomized trial of 121 patients with ANH, defined as an anterior posterior diameter (APD) >or=5 mm after the 20th week of gestation, to evaluate the ability of the antenatal and postnatal ultrasonography results to predict VUR. All infants had two successive ultrasounds at 5 days and 1 month, respectively, after birth. A VCUG was performed at 6 weeks in children with a persistent APD >or=5 mm and/or an ureteral dilatation observed on at least one of two postnatal ultrasounds. In total, 88 patients had VCUG and nine had VUR, with five having high-grade reflux (>grade II). The risk of VUR increased significantly with the degree of APD detected on the postnatal ultrasound scan (p = 0.03). The odds ratios were 5.0 [95% confidence interval (CI) 0.5-51.2] for APD = 7-9 mm and 9.1 (95% CI 1.0-80.9) for APD >or=10 mm. The results of this study show that among our patient cohort antenatal ultrasound was not predictive of reflux. There was, however, a relation between the importance of the postnatal renal pelvis diameter and the risk of VUR. A cut-off of 7 mm showed a fair ability of ultrasonography to predict VUR and a cut-off of 10 mm enabled all severe refluxes in the 88 patients who had a VCUG to be diagnosed.

Ultrasonography as predictor of permanent renal damage in infants with urinary tract infection

AIM

To evaluate the ability of ultrasound (US) in infants (<1 year) with acute urinary tract infection (UTI), to identify those with permanent renal damage (PRD) at scintigraphy 1 year later.

METHODS

US, dimercaptosuccinic acid scintigraphy and voiding cystourethrography were performed in 191 infants.

RESULTS

US was abnormal in 46 infants (24%). PRD was found in 46 infants (24%); 19 of these had abnormal US (sensitivity 41%). In 145 infants without PRD, 27 had abnormal US (specificity 81%). Dilating reflux or verified obstruction occurred in 21 (11%) infants, of whom 18 (86%) had PRD while 28 of 170 (16%) without such diagnoses had PRD. Of 16 infants with dilating reflux, 9 (sensitivity 56%) had abnormal US and 14 (88%) PRD. Dilatation at US was seen in 27 children; 7 of these had dilating reflux and 5 verified obstruction.

CONCLUSION

US performed in association with acute UTI had limited ability to identify children with PRD at (99m)Tc-dimercaptosuccinic acid (DMSA) 1 year later, although abnormal renal size was a strong indicator of renal damage. The ability of US to identify children with dilating reflux was also limited. However, once detected at US, dilatation of the urinary tract was associated with dilating reflux or obstruction in half of the cases. Our study confirms that dilating reflux and obstruction are strong indicators of PRD but only half of those who developed PRD had such diagnoses.

Screening young children with a first febrile urinary tract infection for high-grade vesicoureteral reflux with renal ultrasound scanning and technetium-99m-labeled dimercaptosuccinic acid scanning

OBJECTIVE

To evaluate the predictive value of renal ultrasound scanning and 99m-Technetium-dimercaptosuccinic acid (DMSA) scintigraphy for high-grade vesicoureteral reflux (VUR) in young children with a first urinary tract infection (UTI).

STUDY DESIGN

The medical records of children who had been examined with renal ultrasound scanning, DMSA scanning, and voiding cystourethrography (VCUG) were reviewed. The findings of renal ultrasound scanning, DMSA scanning, and their predictive values were evaluated.

RESULTS

Of 699 children, high-grade VUR (grades III-V) was diagnosed in 119 (17.0%). Signs of renal hypodysplasia (OR, 16.15), cyclic dilatation of pelvicaliceal system (OR, 11.73), hydroureter (OR, 4.00) with renal ultrasound scanning, and renal hypodysplasia (OR, 8.78), acute pyelonephritis (OR, 2.76) with DMSA scanning were associated with high-grade VUR. The sensitivities for high-grade VUR of ultrasound scanning alone (67.2%) or DMSA scanning alone (65.5%) were not as good as that of a both-test strategy, which had a sensitivity rate of 83.2%. The negative predictive value of the both-test strategy was 91.5%.

CONCLUSION

Renal ultrasound scanning and DMSA scanning both should be routinely performed in children with a first febrile UTI. VCUG is only indicated when abnormalities are apparent on either ultrasound scanning or DMSA scanning or both.

Antenatal renal pelvis dilatation: 2-year follow-up with DMSA scintigraphy

The aim of this study was to determine whether a postnatal ultrasound (US) can detect infants with antenatal renal pelvis dilatation (ARPD) who run a minimal risk of renal damage 2 years after birth. The study cohort consisted of 14,000 pregnant women who consecutively underwent routine US examinations during the second trimester. Subsequent examinations were performed on the basis of obstetrical indications. In total, 106 foetuses were diagnosed with ARPD > or =5 mm. Two postnatal US were performed on the newborns: on postpartum days 5-7 and during the third week of life. The findings were considered to be normal when the renal pelvis diameter (RPD) was < or = 7 mm and when there was no calyceal or ureteric dilatation or signs of renal dysplasia or other anomalies. Voiding cystourethrography (VCUG) was done at 6-8 weeks after birth. When the children reached 2 years of age, renal status was evaluated with DMSA scintigraphy or, if not possible, US. In 53 of the 103 children available for evaluation, the postnatal US findings were normal; 49 of the 53 children were also given a DMSA, and the results were normal in all cases. An US scan (all normal) only was performed in three children because the families refused a DMSA. One family refused any form of examination at the 2-year follow-up. Based on our results, we conclude that postnatal US can detect infants who do not require follow-up assessments of renal development.

Harmonic voiding urosonography with a second-generation contrast agent for the diagnosis of vesicoureteral reflux

BACKGROUND

Voiding urosonography with harmonic imaging (VUS HI) has been introduced as a sensitive and radiation-free imaging method for the diagnosis and follow-up of vesicoureteral reflux (VUR) in children.

OBJECTIVE

The purpose of this study was to evaluate the sensitivity of VUS HI using a second-generation US contrast agent compared to standard voiding cystourethrography (VCUG).

MATERIALS AND METHODS

A total of 228 children with 463 kidney-ureter units (KUUs) underwent two cycles of VUS HI and two cycles of VCUG at the same session. VUS HI was performed after intravesical administration of 1 ml of a second-generation US contrast agent (sulphur-hexafluoride gas microbubbles, SonoVue, Bracco, Italy). For statistical analysis we used McNemar's test, Student's t-test and k coefficient tests.

RESULTS

VUR was shown in 161/463 (34.7%) KUUs, 57 by both methods, 90 only by VUS, and 14 only by VCUG. Concordance in findings regarding the presence or absence of VUR was found in 359/463 (77.5%) KUUs (k=0.40). The difference in the detection rate of reflux between the two methods was significant (P<0.01). More importantly, reflux missed by VCUG was of higher grade (2 grade I, 65 grade II, 19 grade III, 4 grade IV) than that missed by VUS (8 grade I, 5 grade II, 1 grade III).

CONCLUSION

VUS HI and a second-generation contrast agent improved the identification of reflux in children. Our data reveal a higher sensitivity of the method compared to VCUG. Thus it can be used as an alternative radiation-free imaging method.

Antenatal hydronephrosis: infants with minor postnatal dilatation do not need prophylaxis

The aim of this study was to determine the occurrence of urinary tract infection (UTI) in infants with antenatal renal pelvis dilatation (ARPD). Consecutive ultrasound (US) screening of 14,000 pregnant women detected ARPD >or=5 mm in 106 foetuses. After birth, two US examinations were performed: on the fifth to seventh day and during the third week of life. The findings were considered normal when renal pelvis dilatation (RPD) was <or=7 mm on both examinations and no other signs of abnormality were present. Voiding cystourethrography (VCUG) was done in all infants 6-8 weeks after birth. One hundred and three infants were followed for 2 years. Antibacterial prophylaxis (trimethoprim 1 mg/kg per day) was given to those with RPD >or=15 mm, vesicoureteric reflux (VUR) grades III-V and suspected obstruction. In 53/103 babies, both US examinations were normal, three had VUR grade I. Two girls had UTI at 18 and 24 months of age, respectively. Among the 50 infants with abnormal initial US, six had VUR, of which four were high grade (IV-V). All four developed UTI. We conclude that UTI is uncommon in infants with two normal postnatal US examinations. Routine use of antibacterial prophylaxis in these infants therefore cannot be recommended.

Antenatally detected hydronephrosis

The strategy of management of children with hydronephrosis has considerably changed as a result of the development of ultrasound techniques, allowing a prenatal detection. Hydronephrosis is defined as a dilation of the renal collecting system, and several entirely different clinical entities can be considered this general heading, whereas early detection may have a different impact depending on the entity considered. The present work aims to describe a certain number of these clinical entities, to discuss the strategic options of management that are proposed, and to evaluate the role of medical imaging, in particular the radionuclide approach. Congenital ureteropelvic junction anomaly, vesicoureteral reflux, posterior urethral valves, and duplex kidney will be successively considered. Multicystic dysplastic kidney disease, although not classified as hydronephrosis, will be mentioned because it may be mistaken for hydronephrosis.

Mild hydronephrosis in newborns and infants: can ultrasound predict the presence of vesicoureteral reflux

The objective of our study was to determine the significance of mild hydronephrosis in newborns and infants as an indicator of vesicoureteral reflux (VUR). The voiding cystourethrography (VCUG) of 573 patients aged 0-18 months with mild, sonographically detected hydronephrosis were reviewed for VUR. Patients with secondary reflux or anomalies making an exact reflux grading impossible were excluded. Normal kidneys, contralateral to hydronephrotic ones, were included. Each kidney was considered separately, forming a total of 1,146 renal units. Mild hydronephrosis was defined as an anteroposterior diameter of the renal pelvis of 0.5-1.5 cm without caliectasis. The International Grading System was used to grade VUR. Seven hundred and thirty-six kidneys had mild hydronephrosis. VUR occurred in 189 out of 736 (25.7%) of these kidneys, and in 108 out of 410 (26.3%) non-distended kidneys, contralateral to hydronephrotic ones (p=0.806). No statistical differences in the frequency of VUR and dilatation were found between the subgroups of patients with and without infection, except for a higher grade of reflux in the group with infection. The frequency of VUR in mildly dilated kidneys was not significantly different from that in non-distended ones. There was a poor correlation between VUR and mild hydronephrosis. The latter should not be considered in itself an indication for VCUG in asymptomatic neonates and infants.

Is screening for vesicoureteral reflux mandatory in infants with antenatal renal pelvis dilatation?

AIM

To determine whether postnatal ultrasound (US) can guide the use of voiding cystourethrography (VCUG) in infants with antenatally detected renal pelvis dilatation (ARPD).

METHODS

14,000 pregnant women consecutively underwent routine US examination during the second trimester. US examinations later in pregnancy were performed as follow-up of previous anomalies or on obstetrical indications. One hundred and six fetuses with ARPD > or =5 mm were identified. Two postnatal US examinations were performed in the newborns: on the 5th to 7th day and during the 3rd week of life. The findings were considered normal when renal pelvis dilatation (RPD) was < or =7 mm on both US examinations, and no calyceal or ureteric dilatation or signs of renal dysplasia or other anomalies were present. VCUG was done 6 to 8 wk after birth.

RESULTS

In 53 of 103 analysable infants, the postnatal ultrasonographic findings were normal. The VCUG was abnormal in three of these 53 infants, all with vesicoureteral reflux (VUR) grade I. Of 50 infants who had abnormal US examinations, six had VUR, four of which were grade IV and V reflux.

CONCLUSION

In infants with ARPD who undergo two postnatal US examinations with RPD < or =7 mm and have no other abnormalities, VCUG is unnecessary.

Infections and vesicoureteral reflux

Vesicoureteral reflux (VUR) is a common condition in children. It may cause and maintain urinary tract infections, eventually leading to progressive renal damage and end-stage renal disease. Ideally, VUR should be detected and treated before renal scarring occurs. Although fetal hydronephrosis on antenatal ultrasound may be the first indicator, the role of further diagnostic investigations in these newborns is still controversial. Because VUR is an inherited condition, offspring of women with a family history of VUR and urinary tract infection should be screened closely for early detection of VUR. Once diagnosed, however, the optimal management of VUR (i.e. medical or surgical treatment) remains controversial. Evidence-based treatment recommendations, like the American Urological Association guidelines, may aid physicians in their therapeutic decision making, but cannot replace personal experience or surgical skill.

Imaging of the neonatal genito-urinary tract

OBJECTIVE

To describe imaging of typical conditions and diseases in the neonatal genito-urinary (GU) tract.

METHOD

The use, the applications, and typical findings using standard imaging techniques (e.g., ultrasound, US, voiding cystourethrography, VCUG) are described, with emphasis on technical aspects, indications, and restrictions in neonatal queries. Only basic applications as used in routine clinical work are included, other more sophisticated and advanced imaging techniques such as scintigraphy, MR-urography, genitography or image-guided interventional procedures will only briefly be mentioned.

SUMMARY AND CONCLUSION

Conventional imaging methods are valuable and - particularly in the neonatal GU tract - sometimes irreplaceable. Skillfully used basic imaging techniques, particularly of US (including modern methods such as Doppler sonography, Harmonic imaging or contrast enhanced US), supplemented by fluoroscopy for VCUG can answer most acutely treatment relevant queries. Rarely early scintigraphic studies, genitography, or MRI may become indicated, usually not for establishing the diagnosis, but to collect additional (functional or anatomical) information necessary for deciding on further treatment, or even image guided interventional procedures may become necessary.

Primary vesicoureteral reflux detected in neonates with a history of fetal renal pelvis dilatation: a prospective clinical and imaging study

OBJECTIVE

To assess the clinical outcome and imaging features of neonatal primary vesicoureteral reflux (VUR).

STUDY DESIGN

We prospectively followed 43 infants with primary VUR identified from among a cohort of 497 infants with fetal renal pelvis dilatation. Postnatal renal ultrasound (US) examinations were performed at 5 days and 1, 3, 6, 12, and 24 months of life. Voiding cystourethrography was performed in the neonatal period and repeated at 12 and 24 months when VUR was persistent. Two radioisotopic examinations, including a 99mTc-MAG3 renogram and a plasma clearance of Cr-51 EDTA, were performed in all children with high-grade reflux.

RESULTS

The incidence of primary VUR in our study group was 9%. Among the 43 patients followed, 11 (26%) had high-grade (IV-V) VUR and 32 (74%) had low-grade VUR. Resolution of reflux occurred in 2 of 11 (18%) patients with high-grade VUR and in 29 of 32 (90.6%) patients with low-grade VUR at age 2 years (P < .001). At age 2 years, 91% of the low-grade refluxing kidneys were normal on US, compared with only 35% of the high-grade refluxing kidneys. Split renal function was within normal range and single-kidney GFR was significantly increased in 13 of the 17 high-grade refluxing kidneys during follow-up. Furthermore, a strong association between dysplasia on US and poor renal function outcome was found.

CONCLUSIONS

In most infants with VUR, the reflux is of low grade and resolves rapidly. In those children with high-grade VUR, spontaneous resolution is rare at age 2 years, but persistent reflux rarely impairs the maturation of renal function.

[Fetal genitourinary anomalies Perinatal and postnatal management with imaging techniques]

Improvements in ultrasound technology and the appropriate timing of antenatal ultrasound has led to refined prenatal diagnosis and enhanced accuracy of diagnosis of fetal renal anomalies and makes it possible to treat obstructive and/or refluxing uropathies before the onset of clinical symptoms. The third trimester renal sonography is the most important to detect hydronephrosis amenable to treatment.Classically, the prenatal diagnosis of hydronephrosis, unilateral renal agenesis, or MDKD initiates postnatal investigations, including sonography, voiding cystourethrography (VCUG), and isotopic renography. The exact degree of renal pelvic dilatation that requires full postnatal investigation is still not entirely resolved. Most authors accept the upper limit of 7 mm for the AP diameter of the renal pelvis. The US examination should be performed after the physiological dehydration period, namely 3-5 days after birth, in an urgent case on the 1st day. A meticulous ultrasound examination performed by a physician who is familiar with the renal abnormalities shows the whole extent of underlying pathology. The role of MR urography in the work-up of renal anomalies, particularly of hydronephrosis, is currently being investigated. Due to the close developmental relationship of the urinary and genital tracts, malformations frequently occur in both of these systems. Therefore in all patients, especially in girls with renal anomalies (unilateral renal agenesis, multicystic dysplastic kidney disease), the internal genitalia need to be evaluated.

Postnatal management of infants with antenatally detected hydronephrosis

With the increasing use of antenatal sonography, fetal hydronephrosis has been reported more frequently. Because of the lack of consensus regarding treatment of these infants, the postnatal approach toward fetal renal pelvis enlargement remains controversial. The aim of this prospective study is to demonstrate the postnatal investigation, treatment, and outcome of infants with prenatally diagnosed hydronephrosis. Infants whose antenatal ultrasound scan showed a fetal renal pelvis of 5 mm or greater were investigated postnatally using ultrasound (US) and voiding cystourethrography. When indicated, isotope studies and intravenous urograms were also performed. We followed prospectively neonates with antenatally diagnosed hydronephrosis and recommended management guidelines on the basis of our findings. In 156 neonates (193 kidney units) that were found to have hydronephrosis, the average gestational age at which the diagnosis was made was 32.94+/-5.10 weeks. The mean duration of postnatal follow-up was 26.3+/-13.56 months (range 3-60 months). The mean APPD of the fetal renal pelvis was 10.35+/-3.24 mm (5-9 mm in 84 kidneys, 10-14 mm in 96 kidneys and > or =15 mm in 13 kidneys). Of the 193 kidney units, 145 units were found to be pathological. The most common detected underlying abnormalities were ureteropelvic junction obstruction (in 91 kidneys; 62.7%) and vesicoureteral reflux (in 24 kidneys; 16.6%). Postnatally, 23 (45%) of 51 patients whose first US was normal were diagnosed postnatally as having urinary tract abnormality. There was a negative correlation between APPD and the rate of spontaneous resolution and positive correlation between APPD and the rate of surgery (P<0.01). In conclusion, because it is not possible to determine an upper limit of normal for the antenatal renal pelvis, any baby with AH should not be considered clinically insignificant. Infants with antenatal renal pelvis measurements > or =5 mm should be investigated postnatally. A normal postnatal ultrasound scan does not preclude the presence of urinary tract abnormality.

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.

Insights into the pathogenesis and natural history of fetuses with renal pelvis dilatation

Fetal renal pelvis dilatation is a frequent abnormality that has been observed in 4.5% of pregnancies. The majority of these cases have a tendency to resolve during infancy. Nevertheless, fetal renal pelvis dilatation may be due to significant structural abnormalities such as pelvi-ureteric junction stenosis or vesico-ureteral reflux that may adversely affect renal function or cause urinary infection or sepsis. This review article aims to summarize the data regarding fetal renal pelvis dilatation and to analyze controversial attitudes in the light of the various lines of practice, and to present rational antenatal and postnatal investigation strategy.

Diagnostic accuracy of postnatal renal pelvic diameter as a predictor of uropathy: a prospective study

BACKGROUND

There is a necessity to standardize postnatal ultrasonographic markers predictive of significant uropathies. The purpose of this study was to assess the accuracy of anteroposterior renal pelvic diameter (APD) on postnatal ultrasound to discriminate between significant uropathy and idiopathic renal pelvic dilatation.

MATERIALS AND METHODS

Neonates ( n=110) who were found to have isolated fetal renal pelvic dilatation underwent systematic investigation and were prospectively followed up. A US scan was performed after the 1st week of life, and all infants underwent voiding cystourethrography. Neonates with an APD larger than 10 mm were examined with renal scintigraphy. Receiver-operating characteristic (ROC) plots were constructed to determine the best cutoffs for APD to identify renal units with significant uropathy as well as those requiring surgical intervention.

RESULTS

The area under the curve (AUC) estimated by the ROC curve was 0.921 (95% CI=0.869-0.957), indicating excellent discriminant power between nonsignificant pelvis dilatation and significant uropathy. A cutoff of 10 mm for APD showed the best accuracy for identifying infants with a significant uropathy (sensitivity, 90.4%; specificity, 91%). To identify infants who required surgical intervention, the calculated AUC was 0.976 (95% CI=0.940-0.993). A cutoff of 15 mm showed the best diagnostic performance for identifying the renal units requiring pyeloplasty (sensitivity, 100%; specificity, 92.5%).

CONCLUSION

Our results suggest that postnatal APD is an excellent test for identifying fetuses with significant uropathy, as well as those requiring postnatal intervention.

Current management of infants with fetal renal pelvis dilation: a survey by French-speaking pediatric nephrologists and urologists

To analyze the current management recommendations among French-speaking physicians treating infants with antenatal renal pelvis dilatation, we surveyed 83 pediatric nephrologists and 68 pediatric urologists by questionnaire. A total of 45 (54%) pediatric nephrologists and 38 (56%) pediatric urologists responded. The threshold for the diagnosis of abnormal fetal renal pelvis dilatation was significantly higher among pediatric urologists than nephrologists. All responders perform renal ultrasound examinations after birth. Postnatal renal pelvis dilatation was considered abnormal if the anteroposterior diameter was >/=11+/-1.9 mm by the pediatric urologists and >/=9+/-2.9 mm by the pediatric nephrologists ( P=0.003). Pediatric urologists were more likely than nephrologists to recommend routine voiding cystourethrography [41% versus 20% ( P=0.04)]. Mercaptoacetyl-triglycine renography was the most routinely used tool to achieve functional evaluation during follow-up among the responders. Pediatric urologists were more likely to recommend surgical treatment in dilated kidneys with initial function <40%. In conclusion, pediatric urologists had significantly higher thresholds for the detection of prenatal and neonatal renal pelvis dilatation. They also more frequently recommended routine voiding cystourethrography and surgical therapy of dilated kidneys with low function than pediatric nephrologists. The variability in attitudes is most probably due to the absence of clear guidelines based on prospective and controlled trials.

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.

Long-term clinical outcome of infants with mild and moderate fetal pyelectasis: validation of neonatal ultrasound as a screening tool to detect significant nephrouropathies

OBJECTIVE

To assess the long-term outcome of infants with mild and moderate fetal pyelectasis and to determine the predictive value of neonatal ultrasound imaging in identifying significant nephrouropathies.

STUDY DESIGN

This prospective study included 213 infants with antenatal mild to moderate pyelectasis who were followed for up to 2 years. Postnatal renal ultrasound examinations were performed at day 5 and months 1, 3, 6, 12 and 24 after birth. Voiding cystourethrography was performed in all infants.

RESULTS

Normal or nonsignificant findings were diagnosed in 130 of 213 (61%) infants. Significant nephrouropathies were diagnosed in 83 of 213 (39%) infants. The sensitivity, specificity, positive predictive value, and negative predictive value of two successive neonatal renal ultrasound examinations performed at day 5 and 1 month to predict significant nephrouropathies were 96%, 76%, 72%, and 97%, respectively. In 102 of 213 (48%) infants with normal neonatal renal ultrasound scans, we later found only three of 102 (3%) cases with significant nephrouropathies.

CONCLUSIONS

We found in a population of infants with mild to moderate fetal pyelectasis a 39% incidence of significant nephrouropathies. Ultrasound is an excellent screening tool with high sensitivity and negative predictive value that allows avoidance of unjustified medical follow-up in patients with two normal neonatal ultrasound scans.

Sonographic diagnosis of urethral anomalies in infants: value of perineal sonography

OBJECTIVE

To assess the value of urethral sonography including a perineal approach in evaluating urethral anomalies in infants.

METHODS

A radiology database review identified 88 patients (mean age +/- SD, 64 +/- 84 days) who underwent voiding cystourethrography (VCUG) and urethral sonography as part of extended sonography of the urinary tract. Sonographic and VCUG images and reports were reviewed to assess agreement between both modalities for detection of urethral anomalies.

RESULTS

Sonography facilitated the correct diagnosis of all 3 posterior urethral valves. The only urethral diverticulum, the only ectopic ureteric insertion into the urethra, the only urogenital sinus, and the only urethrovaginal fistula were also shown on sonography. In 73 (94%) of 78 cases, sonography correctly showed the absence of anomalies. In 5 infants, sonography could not reliably assess the urethra and showed indirect signs of urethral anomalies; however, these patients had normal urethras on VCUG.

CONCLUSIONS

Our data show that sonography of the urethra is a valuable tool for diagnosis of urethral anomalies. Especially, negative findings on sonography are highly suggestive of the absence of urethral anomalies. Positive or equivocal sonographic findings should indicate VCUG.

[Advances in pediatric sonography]

Advances in the field of ultrasound technology and ultrasound contrast media over the past few years have also brought major improvements to pediatric sonography. Accordingly, contrast-enhanced voiding urosonography has become a valuable alternative in the diagnosis of vesicoureteral reflux. It is possible to achieve significant reduction in radiation exposure replacing the conventional radiologic methods used for reflux diagnosis with contrast-enhanced ultrasound. Through the introduction of harmonic imaging, an ultrasound scanning modality with high spatial and contrast resolution has become available. The modality was initially propagated as one to be applied in difficult-to-scan adults. However, initial experiences in pediatric applications are demonstrating the significant improvement it can bring in the ultrasound image quality, for example, in intestinal ultrasound. A further development is three-dimensional [3D] imaging using ultrasound. 3D-ultrasound not only offers an improvement in diagnosis but also in the acceptance of ultrasound in interdisciplinary work and teaching. The first applications of 3D-ultrasound in pediatrics are focusing on brain ultrasound and volume measurement of the kidneys.

Investigating the newborn kidney: update on imaging techniques

Advances in imaging have resulted in higher-quality resolution. Techniques formerly considered to give pure anatomic information are now providing functional data, but the functions provided are not those typically measured in pathophysiologic terms. Instead, the data provided demand that we incorporate this new information into the understanding of the pathologic processes that confront us in clinical practice. Ultrasound provides information about kidney volume, blood flow velocity and blood flow volume. Radioisotopes can show the ability of the proximal tubules to extract the tracer from the blood as well as the ability of the kidney to clear the tracer into the bladder. Magnetic resonance imaging provides information about water content of the kidney.

The PIC cystogram: a novel approach to identify "occult" vesicoureteral reflux in children with febrile urinary tract infections

PURPOSE

When the standard cystogram does not show vesicoureteral reflux in children who have experienced febrile urinary tract infections (UTIs), clinical management is controversial. We postulated that vesicoureteral reflux accounts for such UTIs but is "occult." We tested this hypothesis by using a novel method, PIC cystography (Positioning the Instillation of Contrast at the ureteral orifice) at the time of cystoscopy.

MATERIALS AND METHODS

We performed PIC cystography with instillation of contrast medium at the ureteral orifice consecutively and prospectively in 57 children who underwent cystoscopy between November 1999 and February 2002 to evaluate febrile UTIs in 40 patients, dysfunctional voiding in 14 and hydronephrosis in 3. The control group (27 patients, 54 renal units) was used to assess the accuracy of PIC by comparing the results against those with the standard cystogram in children who did not have febrile infection and did not demonstrate vesicoureteral reflux (15 patients, 30 renal units), and in those who had febrile infection and vesicoureteral reflux (12 patients, 24 renal units). The study group (30 patients, 60 renal units) served to assess the incidence of "occult" vesicoureteral reflux in children who experienced febrile UTIs yet did not have vesicoureteral reflux on standard cystography.

RESULTS

CONTROL GROUP

In children without febrile UTIs all 30 ureteral orifices had a normal endoscopic appearance and no vesicoureteral reflux by PIC cystography. In children with febrile UTIs 15 ureteral orifices with known vesicoureteral reflux were lateral and/or patulous and demonstrated vesicoureteral reflux by PIC, 4 appeared normal and did not exhibit vesicoureteral reflux on standard cystography or by PIC, and 5 were lateral and/or patulous in appearance and did not display vesicoureteral reflux on standard cystography, but did show vesicoureteral reflux by PIC. These findings reveal that PIC cystography is 100% sensitive at demonstrating reflux already known by standard cystogram, is 87% specific as it showed reflux in 5 of 39 renal units not revealed by a standard cystogram and has an overall accuracy of 91%.

STUDY GROUP

At cystoscopy all 30 children demonstrated an abnormal appearance of one or both ureteral orifices. PIC cystography showed vesicoureteral reflux in all 30 children (48 renal units, 12 unilateral and 18 bilateral). The remaining ureteral orifices (12), which appeared normal, did not permit vesicoureteral reflux. Children with vesicoureteral reflux by PIC were treated with antimicrobial prophylaxis (26) or ureteral reimplantation (4, 2 unilateral and 2 bilateral reimplantation) Postoperatively, these children did not experience a febrile UTI during followup (average 8 months).

CONCLUSIONS

PIC cystography is simple to perform using routinely available operating room equipment and does not artifactually induce vesicoureteral reflux. The incidence of "occult" vesicoureteral reflux in children who experience febrile UTIs without vesicoureteral reflux on standard cystography is 100% by PIC cystography. PIC cystography should be done when vesicoureteral reflux is suspected in children who experience febrile UTIs but do not exhibit reflux on standard cystography.

Vesicoureteric reflux and reflux nephropathy

Reflux nephropathy i.e. renal scarring associated with vesico-ureteric reflux (VUR) and urinary tract infection (UTI) was originally considered an acquired disease. The renal scarring seems to get worse with recurrent urine infections especially in the young. Therefore, in the past much effort was undertaken to correct the VUR surgically and minimize the number of recurrent urinary tract infections by antibiotic prophylaxis with the hope of reducing if not arresting the onset of complications that follow i.e. hypertension and renal failure. However, it is now becoming clear that reflux nephropathy encompass at least two major categories of disease; "acquired" renal scarring secondary to UTI and VUR predominantly affecting females and "congenital" scarring with dysplastic features associated with prenatal VUR but with no infection and predominantly affecting boys. The latter is much less common but is disproportionately represented in the group of patients with reflux nephropathy that go on to develop renal failure. Unfortunately, the susceptibility to renal scarring, the onset of hypertension and progression to renal failure seems to be significantly influenced by genetic factors and hence measures undertaken to prevent recurrence of UTI may not change the ultimate outcome although it will certainly improve the comfort of the individual. Therefore, the extensive investigation and management routines adopted today in these children may not be cost-effective in preventing end stage renal disease in VUR. The progression to renal failure, however, can be delayed but not halted with adequate control of high blood pressure and hence the need for life long follow-up.

Results of systematic screening for minor degrees of fetal renal pelvis dilatation in an unselected population

OBJECTIVE

The purpose of this study was to determine the incidence of minor degrees of renal pelvis dilatation that is detected by antenatal ultrasound scanning in an unselected population and its value in the prediction of significant uropathies.

STUDY DESIGN

This prospective study was conducted over a 24-month period. Infants with an anteroposterior pelvic diameter of >or=4 mm in the second trimester and/or >or=7 mm but <15 mm in the third trimester were enrolled.

RESULTS

Pyelectasis was found in 4.5% of 5643 fetuses (1.5% with significant uropathy). Among the 213 infants whose cases were followed, 132 infants (62%) had renal anomalies, but only 83 infants (39%) had significant uropathies. The ability of the third-trimester renal pelvis dilatation to predict renal abnormalities showed a positive predictive value of 69%. Pyelectasis that was detected only in the second trimester revealed a significant uropathy in 12% of the infants.

CONCLUSION

Pyelectasis was found in 4.5% of fetuses. The third-trimester anteroposterior renal pelvis diameter of >or=7 mm was the best ultrasound criterion to predict postnatal uropathies.

Conventional imaging in paediatric uroradiology

OBJECTIVE

To briefly describe basic conventional imaging in paediatric uroradiology.

METHOD

The state of the art performance of standard imaging techniques (intravenous urography (IVU), voiding cystourethrography (VCU), and ultrasound (US)) is described, with emphasis on technical aspects, indications, and patient preparation such as adequate hydration. Only basic applications as used in routine clinical work are included.

RESULT AND CONCLUSION

Conventional imaging methods are irreplaceable. They cover the majority of daily clinical routine queries, with consecutive indication of more sophisticated modalities in those patients who need additional imaging for establishing the final diagnosis or outlining therapeutic options.

Results of systematic voiding cystourethrography in infants with antenatally diagnosed renal pelvis dilation

OBJECTIVES

To assess the yield of neonatal renal ultrasonography as a predictor of abnormalities on voiding cystourethrography (VCUG).

STUDY DESIGN

We prospectively followed 264 infants with antenatal renal pelvis dilation. Two successive neonatal renal ultrasound examinations were performed at day 5 and 1 month after birth. VCUG was performed in all infants.

RESULTS

Neonatal ultrasound findings were abnormal in 190 infants (72% of total). Among them, 63 (33%) had an abnormal VCUG. The most common abnormalities were primary vesico-ureteral reflux (VUR) in 30 infants, VUR into the lower pole of a duplex kidney in 14, refluxing megaureter in 9, posterior urethral valves in 5, and ureterocele in 5. When both neonatal ultrasound findings were normal (74 infants), the VCUG showed abnormalities in only 5 (6.7%) patients (4 low-grade primary VUR and 1 posterior urethral valve). The sensitivity, specificity, positive predictive value, and negative predictive value of 2 successive ultrasound scans in the neonatal period to predict an abnormality on VCUG were 93%, 35%, 33%, and 93%, respectively.

CONCLUSIONS

A normal-appearing urinary tract on 2 successive neonatal ultrasound scans rarely coexists with abnormal findings at VCUG. Therefore, in such patients, VCUG does not seem justified.