Diffusion tensor imaging based multiparametric characterization of renal lesions in infants with urinary tract infections: an explorative study.

BACKGROUND: Conventional diffusion weighted imaging (DWI) is a promising non-invasive tool in the evaluation of infants with symptomatic urinary tract infections (UTI). The use of multiparametric diffusion tensor imaging (DTI) provides further information on renal pathology by reflecting renal microstructure. However, its potential to characterize and distinguish between renal lesions, such as acute pyelonephritic lesions, permanent renal damages or dysplastic changes has not been shown. This study aimed to evaluate the potential of multiparametric DTI for characterization of renal lesions with purpose to distinguish acute pyelonephritis from other renal lesions in young infants with their first UTI. METHODS: Nine kidneys in seven infants, age 1.0-5.6 months, with renal lesions i.e. uptake reductions, on acute scintigraphy performed after their first UTI, were included. The DTI examinations were performed during free breathing without sedation. The signal in the lesions and in normal renal tissue was measured in the following images: b0, b700, apparent diffusion coefficient (ADC), and fractional anisotropy (FA). In addition, DTI tractographies were produced for visibility. RESULTS: There was a difference between lesions and normal tissue in b700 signal (197 ± 52 and 164 ± 53, p = 0.011), ADC (1.22 ± 0.11 and 1.45 ± 0.15 mm2/s, p = 0.008), and FA (0.18 ± 0.03 and 0.30 ± 0.10, p = 0.008) for all nine kidneys. Six kidneys had focal lesions with increased b700 signal, decreased ADC and FA indicating acute inflammation. In three patients, the multiparametric characteristics of the lesions were diverging. CONCLUSION: Multiparametric DTI has the potential to further characterize and distinguish acute pyelonephritis from other renal lesions in infants with symptomatic UTI.

A scoring system for predicting downgrading and resolution of high-grade infant vesicoureteral reflux.

AIM: Aim of the study was to provide a scoring system for predicting downgrading and resolution of infantile high-grade vesicoureteral reflux (VUR). METHODS: Eighty-nine infants (65 boys) with high-grade VUR (grade 4-5) diagnosed at median age 2.5 months and followed to 39 months had repeated investigations of VUR grade, renal damage/function and bladder function. Recurrent urinary tract infections (UTIs) were registered. Risk variables collected at 1 year were analysed as independent factors for spontaneous resolution to grades ≤2 and 0, using univariable/multivariable logistic regression. RESULTS: A scoring system was built with a total of 14 points from four independent risk factors (sex, breakthrough UTI, type of renal damage and subnormal glomerular filtration rate). Children with persistent VUR (grade 3-5) had higher scores compared with the group with spontaneous resolution (grade 0-2) (mean 7.9 vs. 4.5, P < .0001). A score of ≥8 points indicated a low probability of VUR resolution (≤14%). The model was considered excellent based on area under the ROC curve (0.82) and showed satisfactory internal validity. CONCLUSION: This model provides a practical tool in the management of infants born with high-grade reflux. High scores at one year of age indicate a high risk of persistent dilated reflux.

Urinary tract infection in small children: the evolution of renal damage over time.

BACKGROUND: Our objective was to analyze the evolution of kidney damage over time in small children with urinary tract infection (UTI) and factors associated with progression of renal damage. METHODS: From a cohort of 1003 children <2 years of age with first-time UTI, a retrospective analysis of 103 children was done. Children were selected because of renal damage at index 99mTc-dimercaptosuccinic acid (DMSA) scintigraphy at least 3 months after UTI, and a late DMSA scan was performed after at least 2 years. Damage was classified as progression when there was a decline in differential renal function (DRF) by ≥4%, as regression when there was complete or partial resolution of uptake defects. RESULTS: Of 103 children, 20 showed progression, 20 regression, and 63 remained unchanged. There were no differences between groups regarding gender or age. In the progression group, 16/20 (80%) children had vesicoureteral reflux (VUR) grade III-V and 13 (65%) had recurrent UTI. In multivariable regression analysis, both VUR grade III-V and recurrent UTI were associated with progression. In the regression group, 16/20 (80%) had no VUR or grade I-II, and two (10%) had recurrent UTI. CONCLUSIONS: Most small children with febrile UTI do not develop renal damage and if they do the majority remain unchanged or regress over time. However, up to one-fifth of children with renal damage diagnosed after UTI are at risk of renal deterioration. These children are characterized by the presence of VUR grades III-V and recurrent febrile UTI and may benefit from follow-up.

The Swedish infant high-grade reflux trial: Study presentation and vesicoureteral reflux outcome.

INTRODUCTION: High-grade vesicoureteral reflux (VUR) in infants is associated with congenital renal abnormalities, recurrent UTI, and bladder dysfunction. Endoscopic treatment (ET) is a well-established method in children with low to moderate reflux grades, but there is a lack of randomised controlled trials regarding the use of ET versus continuous antibiotic prophylaxis in infants with high-grade VUR. OBJECTIVE: This study aimed to determine whether high-grade VUR in infants can be treated with endoscopic injection and whether ET is superior to antibiotic prophylaxis in the treatment of VUR. MATERIALS AND METHODS: This prospective, randomised, controlled, multicentre, 1-year follow-up trial comprised 77 infants (55 boys, 22 girls) <8 months of age with VUR grade 4-5 (n = 30/n = 47). Of the infants, 52 (68%) had bilateral VUR. Thirty-nine were randomised to antibiotic prophylaxis and 38 to ET (with prophylaxis until resolution). Voiding cystourethrogram, ultrasound, renal scintigraphy, and free voiding observation were performed at study entry and after 1 year to evaluate VUR grade, and renal and bladder function. RESULTS: VUR grade ≤2 was seen in 22 (59%) infants in the endoscopy group and eight (21%) in the prophylaxis group at follow-up (p = 0.0014). The success rate in the endoscopy group was 100% in unilateral grade 4, falling to 31% in bilateral grade 5 (p = 0.0094). Correspondingly, the results in the prophylaxis group were 40% in grade 4 down to 0% in bilateral grade 5 (p = 0.037) (Table). Logistic regression analyses identified ET, VUR grade 4, unilaterality, and low residual urine at baseline as positive predictors of VUR down-grading to ≤2 (area under ROC curve 0.88). In four patients with reflux resolution after one injection, dilating reflux recurred at the 1-year follow-up. One patient had a UTI possibly related to ET. In our material four patients required re-implantation, of whom one was obstructive after injection. DISCUSSION: The opportunity to offer even small infants with high-grade VUR an alternative, minimally invasive treatment option is a great advance in paediatric urology. In this high-risk group, bilateral VUR grade 5 stands out with its poor bladder function and low chance of resolution. The recurrence rate of dilating VUR after successful ET is consistent with previous studies. The limitations are the relatively small number of patients and the short follow-up. CONCLUSION: High-grade VUR in infants can be treated with injection therapy and the resolution rate is higher than that of prophylaxis treatment. The complication rate is low and VUR grade 4, unilaterality, and low residual urine are favourable for the resolution and down-grading of VUR.

Urinary tract infection in infants: the significance of low bacterial count.

BACKGROUND: In national guidelines for urinary tract infection (UTI) in children, different cut-off levels for defining bacteriuria are used. In this study, the relationship between bacterial count in infant UTI and inflammatory parameters, frequency of vesicoureteral reflux (VUR), kidney damage, and recurrent UTI was analyzed. METHODS: We conducted a population-based retrospective study of 430 infants age <1 year with symptomatic UTI diagnosed by suprapubic aspiration. Clinical and laboratory parameters, findings on voiding cystourethrography and (99m)technetium dimercapto-succinic acid scintigraphy, and frequency of recurrence were related to bacterial count at the index UTI. RESULTS: Eighty-three (19%) infants had bacterial counts <100,000 colony-forming units (CFU)/ml and 347 (81%) had ≥100,000 CFU/ml. There was similar frequency of VUR (19% in both groups), kidney damage (17 and 23%, p = 0.33) and recurrent UTI (6 and 12%, p = 0.17) in the low and high bacterial group. Non-E. coli species were more prevalent (19 versus 6%, p = 0.0006) and mean C-reactive protein was lower (50 vs. 79 mg/l, p <0.0001) in the low bacteria group. CONCLUSIONS: UTI with low bacterial count is common and of importance since it may be associated with VUR and renal damage. Non-E. coli species and low inflammatory response were more prevalent in UTI with low bacterial count.

Measurements of total and regional body composition in preschool children: A comparison of MRI, DXA, and anthropometric data.

OBJECTIVE: There are clear sex differences in the distribution of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in adults, with males having more VAT and less SAT than females. This study assessed whether these differences between the sexes were already present in preschool children. It also evaluated which measures of body composition were most appropriate for assessing abdominal obesity in this age group. DESIGN AND METHODS: One-hundred and five children (57 boys and 48 girls) participated in the study. Body composition was measured using dual-energy X-ray absorptiometry (DXA). Weight, height, and waist circumference (WC) were also recorded. Magnetic resonance imaging (MRI) of the entire abdomen using sixteen 10-mm-thick T1 -weighted slices was performed in a subgroup of 48 children (30 boys and 18 girls); SAT and VAT volumes were measured using semiautomated segmentation. RESULTS: Boys had significantly more VAT than girls (0.17 versus 0.10 l, P < 0.001). Results showed that VAT correlated significantly with all measurements of anthropometry (P < 0.01) after adjusting for SAT and for total fat mass measured with DXA. The mean limits of agreement between DXA and MRI regarding truncal FM were calculated to be -11.4 (range -17.8 to -3.6), using a Bland-Altman plot. CONCLUSION: Sex differences in adipose tissue distribution are apparent at an early age. MRI is the best method with which to study abdominal fat distribution in young children.

Contrast-enhanced magnetic resonance imaging in pediatric patients: review and recommendations for current practice.

Magnetic resonance imaging (MRI), frequently with contrast enhancement, is the preferred imaging modality for many indications in children. Practice varies widely between centers, reflecting the rapid pace of change and the need for further research. Guide-line changes, for example on contrast-medium choice, require continued practice reappraisal. This article reviews recent developments in pediatric contrast-enhanced MRI and offers recommendations on current best practice. Nine leading pediatric radiologists from internationally recognized radiology centers convened at a consensus meeting in Bordeaux, France, to discuss applications of contrast-enhanced MRI across a range of indications in children. Review of the literature indicated that few published data provide guidance on best practice in pediatric MRI. Discussion among the experts concluded that MRI is preferred over ionizing-radiation modalities for many indications, with advantages in safety and efficacy. Awareness of age-specific adaptations in MRI technique can optimize image quality. Gadolinium-based contrast media are recommended for enhancing imaging quality. The choice of most appropriate contrast medium should be based on criteria of safety, tolerability, and efficacy, characterized in age-specific clinical trials and personal experience.

Ultrasonography and renography to visualize upper urinary tract in children with meningomyelocele - a prospective study.

OBJECTIVE: Ultrasonography (US) is commonly used to visualize the upper urinary tract in children and adolescents with meningomyelocele (MMC). The aim of this investigation was to prospectively evaluate US in those with spinal angulation or obesity and compare it to the corresponding results obtained by mercaptoacetyltriglycine renography. PATIENTS AND METHODS: Twenty-five children and adolescents with MMC and pronounced angulation of the spine or obesity, were prospectively investigated with both US and renography during the period 2006 to 2008. RESULTS: In 13 (52%) patients the kidneys could not be fully evaluated; in 4 (16%) neither renal size nor pelvic dilation, in 12 (48%) renal length and in 5 (20%) dilation was not accessible. In 23 individuals where dilatation could be evaluated uni- or bilaterally, US was compared to OEE% (%outflow excretion efficiency) at renography. In 1 of these individuals there was normal OEE% while slight dilatation on US was noticed. In 2/15 individuals, split function at renography did not correlate with renal length on US. CONCLUSION: Severe spinal angulation and obesity in individuals with MMC reduced the possibility to evaluate the urinary tract by US. However, it seems that renography could be a reliable alternative to evaluate renal condition in those patients where US is insufficient.

Imaging strategy for infants with urinary tract infection: a new algorithm.

PURPOSE: We analyzed clinical data for prediction of permanent renal damage in infants with first time urinary tract infection. MATERIALS AND METHODS: This population based, prospective, 3-year study included 161 male and 129 female consecutive infants with first time urinary tract infection. Ultrasonography and dimercapto-succinic acid scintigraphy were performed as acute investigations and voiding cystourethrography within 2 months. Late scintigraphy was performed after 1 year in infants with abnormality on the first dimercapto-succinic acid scan or recurrent febrile urinary tract infections. End point was renal damage on the late scan. RESULTS: A total of 270 patients had end point data available, of whom 70 had renal damage and 200 did not. Final kidney status was associated with C-reactive protein, serum creatinine, temperature, leukocyturia, non-Escherichia coli bacteria, anteroposterior diameter on ultrasound and recurrent febrile urinary tract infections. In stepwise multiple regression analysis C-reactive protein, creatinine, leukocyturia, anteroposterior diameter and non-E.coli bacteria were independent predictors of permanent renal damage. C-reactive protein 70 mg/l or greater combined with anteroposterior diameter 10 mm or greater had sensitivity of 87% and specificity of 59% for renal damage. An algorithm for imaging of infants with first time urinary tract infection based on these results would have eliminated 126 acute dimercapto-succinic acid scans compared to our study protocol, while missing 9 patients with permanent renal damage. CONCLUSIONS: C-reactive protein can be used as a predictor of permanent renal damage in infants with urinary tract infection and together with anteroposterior diameter serves as a basis for an imaging algorithm.

Adipose tissue distribution in children: automated quantification using water and fat MRI.

PURPOSE: To develop and validate a method for rapid acquisition and automated processing of magnetic resonance (MR) images for analysis of abdominal adipose tissue distribution in children. MATERIALS AND METHODS: The study included 21 (10 girls, 11 boys) healthy 5-year-old children. Rapid water and fat MR imaging (6 sec) was performed using a 2-point-Dixon technique on a 1.5T MR scanner using an 8-channel cardiac coil. An automated image processing algorithm was developed for automated segmentation of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), respectively. The results from the fully automated analysis were compared to those from a semiautomated analysis, performed by three operators, from the same images. RESULTS: The automated analysis was seen to give results with strong correlation to the reference measurements (r >or= 0.997); however, the SAT volume was underestimated by 9.4 +/- 3.8%. The accuracy of the automated segmentation of VAT and SAT (TP: true positive, FP: false positive, mean +/- SD, %) was TP: 83.6 +/- 8.5, FP: 12.7 +/- 6.8; and TP: 89.9 +/- 3.6, FP: 0.7 +/- 0.3, respectively. CONCLUSION: A method for rapid imaging and fully automated postprocessing of abdominal adipose tissue distribution is presented. The method allows robust and time-efficient measurement of adipose tissue distribution in young children.

The Swedish reflux trial in children: I. Study design and study population characteristics.

PURPOSE: We compared the rates of febrile urinary tract infection, kidney damage and reflux resolution in children with vesicoureteral reflux treated in 3 ways, including antibiotic prophylaxis, endoscopic therapy and surveillance with antibiotics only for symptomatic urinary tract infection. MATERIALS AND METHODS: Children 1 to younger than 2 years with grade III-IV reflux were recruited into this prospective, open, randomized, controlled, multicenter study and followed for 2 years after randomization. The main study end points were recurrent febrile urinary tract infection, renal status on dimercapto-succinic acid scintigraphy and reflux status. Outcomes were analyzed by the intent to treat principle. RESULTS: During a 6-year period 128 girls and 75 boys entered the study. In 96% of cases reflux was detected after urinary tract infection. The randomization procedure was successful and resulted in 3 groups matched for relevant factors. Recruitment was slower than anticipated but after patients were entered adherence to the protocol was good. Of the children 93% were followed for the intended 2 years without a treatment arm change. All except 2 patients completed 2-year followup scintigraphy. CONCLUSIONS: Recruitment was difficult but a substantial number of children were entered and randomly assigned to 3 groups with similar basic characteristics. Good adherence to the protocol made it possible to address the central study questions.

The Swedish reflux trial in children: IV. Renal damage.

PURPOSE: We compared the development of new renal damage in small children with dilating vesicoureteral reflux randomly allocated to antibiotic prophylaxis, endoscopic treatment or surveillance as the control group. MATERIALS AND METHODS: Included in the study were 128 girls and 75 boys 1 to younger than 2 years with grade III-IV reflux. Voiding cystourethrography and dimercapto-succinic acid scintigraphy were done before randomization and after 2 years. Febrile urinary tract infections were recorded during followup. Data analysis was done by the intent to treat principle. RESULTS: New renal damage in a previously unscarred area was seen in 13 girls and 2 boys. Eight of the 13 girls were on surveillance, 5 received endoscopic therapy and none were on prophylaxis (p = 0.0155). New damage was more common in children with than without febrile recurrence (11 of 49 or 22% vs 4 of 152 or 3%, p <0.0001). CONCLUSIONS: In boys the rate of new renal damage was low. It was significantly higher in girls and most common in the control surveillance group. There was also a strong association between recurrent febrile UTIs and new renal damage in girls.

The Swedish reflux trial in children: II. Vesicoureteral reflux outcome.

PURPOSE: We compared reflux status in children with dilating vesicoureteral reflux treated in 3 groups, including low dose antibiotic prophylaxis, endoscopic therapy and a surveillance group on antibiotic treatment only for febrile urinary tract infection. MATERIALS AND METHODS: A total of 203 children 1 to younger than 2 years with grade III-IV reflux were recruited into this open, randomized, controlled trial. Endoscopic treatment was done with dextranomer/hyaluronic acid copolymer. The main end point was reflux status after 2 years. Data were analyzed by the intent to treat principle. RESULTS: Reflux status improved in all 3 treatment arms. Of patients in the prophylaxis, endoscopic and surveillance groups 39%, 71% and 47%, respectively, had reflux resolution or downgrading to grade I-II after 2 years. This was significantly more common in the endoscopic than in the prophylaxis and surveillance groups (p = 0.0002 and 0.0030, respectively). After 1 or 2 injections 86% of patients in the endoscopic group had no or grade I-II reflux but recurrent dilating reflux was seen in 20% after 2 years. CONCLUSIONS: Endoscopic treatment resulted in dilating reflux resolution or downgrading in most treated children. After 2 years endoscopic treatment results were significantly better than the spontaneous resolution rate or downgrading in the prophylaxis and surveillance groups. However, of concern is the common reappearance of dilating reflux after 2 years.

Value of ultrasound in evaluation of infants with first urinary tract infection.

PURPOSE: We evaluated the role of ultrasound in diagnosing and treating infants with a first urinary tract infection with a focus on important structural abnormalities. MATERIALS AND METHODS: In a setting of limited prenatal ultrasound screening this population based, prospective, 3-year study included 161 male and 129 female infants. Ultrasound and dimercapto-succinic acid scintigraphy were performed as initial investigations and voiding cystourethrography was conducted within 2 months. RESULTS: Ultrasound revealed dilatation in 15% of patients and increased kidney length in 28%. Sensitivity for detecting scintigraphic abnormality was 48%. Renal length was significantly correlated to inflammatory parameters, including scintigraphic abnormalities. Important structural abnormalities were detected in 40 cases, with 30 on ultrasound, while 10 of 27 cases of dilating reflux (mostly grade III) were missed. Outside the study there were 28 additional cases of structural abnormality, of which 15 were detected prenatally. CONCLUSIONS: Ultrasound detected most structural abnormalities except grade III reflux. Since it is noninvasive, ultrasound has a place in the evaluation of infants with urinary tract infection, especially in the absence of prenatal ultrasound during late pregnancy. Kidney length in infants with acute infection correlated with inflammatory parameters, and the clinical importance of this finding needs to be studied further.

Predictive factors for resolution of congenital high grade vesicoureteral reflux in infants: results of univariate and multivariate analyses.

PURPOSE: We studied variables with impact on cessation of congenital high grade vesicoureteral reflux in univariate analyses and provide a multivariate model for prediction of reflux resolution. MATERIALS AND METHODS: A total of 80 male and 35 female infants (median age 2.7 months) were included in this prospective observational study. Of the cases 71% were diagnosed after urinary tract infection and 26% after prenatal ultrasound. Reflux was bilateral in 70% of the patients and maximum grade was III in 16%, IV in 45% and V in 39%. The study protocol included repeat videocystometries, renal scintigrams, chromium edetic acid clearances and free voiding observations. Median followup was 36 months. RESULTS: Overall spontaneous reflux resolution, including cases downgraded to grade I to II, was 38%. Variables significantly negatively correlated to resolution were breakthrough febrile urinary tract infection, bladder dysfunction, higher grade of reflux at inclusion, renal abnormality, subnormal renal function, increased bladder capacity, residual urine and passive occurrence of reflux. Multivariate Cox proportional hazard model with stepwise selection identified 3 independent predictors--renal abnormality (hazard ratio 0.45, 95% CI 0.31-0.64, p <0.0001), bladder dysfunction (hazard ratio 0.43, 95% CI 0.29-0.64, p <0.0001) and breakthrough urinary tract infection (hazard ratio 0.38, 95% CI 0.18-0.78, p = 0.009). Performance of the model was evaluated by the receiver operating characteristic curve, with a calculated area under the curve of 83%. CONCLUSIONS: Overall resolution rate in congenital high grade vesicoureteral reflux is high during the first years of life. By multivariate analyses renal abnormality, bladder dysfunction and breakthrough febrile urinary tract infection were identified as strong independent negative predictive factors for reflux resolution.

Pharmacokinetics and safety of gadobutrol-enhanced magnetic resonance imaging in pediatric patients.

OBJECTIVES: This clinical study investigated the pharmacokinetics and safety of gadobutrol, a magnetic resonance (MR) imaging extracellular contrast agent, in pediatric patients aged 2 to 17 years. MATERIALS AND METHODS: In this open-label, multicenter study, patients scheduled for routine contrast-enhanced MR imaging of the brain, spine, liver or kidney, or MR angiography received a single intravenous injection of gadobutrol (0.1 mmol/kg/0.1 mL/kg). Patients were stratified by age groups (2-6, 7-11, and 12-17 years). Blood and urine samples were collected at prespecified time points and analyzed for gadolinium concentrations. Plasma data were evaluated by means of a nonlinear mixed effects model, and urine data were analyzed using descriptive statistics. In addition, the safety of gadobutrol was evaluated. RESULTS: A total of 130 patients (2-6 years, n = 45; 7-11 years, n = 39; 12-17 years, n = 46) were included in the final population pharmacokinetic analysis. Gadobutrol pharmacokinetics in children aged 2 to 17 years were adequately described by an open 2-compartment model with elimination from the central compartment. The median estimates (2.5th percentile, 97.5th percentile) of body weight-normalized total body clearance (L/h/kg) per age group were 0.10 (0.05, 0.17) for all ages, 0.13 (0.09, 0.17) in the 2 to 6 year age group, 0.10 (0.05, 0.17) in the 7 to 11 year age group and 0.09 (0.05, 0.10) in the 12 to 17 year age group. The body weight-normalized median estimates of total volume of distribution (L/kg) were 0.20 (0.12, 0.28) for all ages, 0.24 (0.20, 0.28) in the 2 to 6 year age group, 0.19 (0.14, 0.23) in the 7 to 11 year age group and 0.18 (0.092, 0.23) in the 12 to 17 year age group. Median gadolinium plasma concentrations at 20 minutes postinjection were simulated using the population pharmacokinetic model and ranged from 414 (13 kg subject) to 518 micromol/L (65 kg subject). Body weight was identified as the major covariate influencing the pharmacokinetic parameters of total body clearance and central volume of distribution. Age was not found to be an additional independent parameter. The median amount of renally excreted gadolinium was 77.0% of the administered dose within 6 hours postinjection, indicating that gadobutrol was renally excreted in this pediatric population aged 2 to 17 years. Gadobutrol was well tolerated, with drug-related adverse events of mild intensity reported for 8 (5.8%) of 138 patients. CONCLUSIONS: Observed differences in pharmacokinetics were attributed to body weight, with no additional independent effect of age. Thus, no dose adjustment from the standard dose of gadobutrol in adults based on body weight (0.1 mmol/kg) is necessary in pediatric patients aged 2 to 17 years. Gadobutrol was safe and well tolerated in the pediatric population in this study.

Normal dimercaptosuccinic acid scintigraphy makes voiding cystourethrography unnecessary after urinary tract infection.

OBJECTIVE: To test the hypothesis that infants with dilating vesicoureteral reflux (VUR) have abnormal acute dimercaptosuccinic acid (DMSA) scintigraphy results, as was suggested by an earlier retrospective study. STUDY DESIGN: We conducted a prospective study of infants <1 year old with first diagnosed symptomatic urinary tract infection at the Children's Hospital of Göteborg, Sweden. Two hundred ninety consecutive children (161 boys and 129 girls) with complete records were examined. Renal ultrasound scanning and DMSA scintigraphy were performed within a few days from diagnosis, and VCU was performed within 2 months. RESULTS: VUR was found in 52 children, of which 27 had dilating VUR (grade III-V). DMSA scintigraphy results were abnormal in 149 infants (51%), 105 of 238 (44%) without VUR, 18 of 25 (72%) with VUR grade I to II, and 26 of 27 (96%) with VUR grade III to V (P <.001). CONCLUSION: DMSA scintigraphy results were abnormal in all 27 infants with dilating VUR except 1. This single false-negative finding should be compared with 140 unnecessary VCU investigations. This supports our hypothesis that DMSA scintigraphy results are abnormal when there is dilating VUR. Thus, a normal DMSA scan makes VCU unnecessary in the primary examination of infants with UTI.

Relationship among vesicoureteral reflux, urinary tract infection and renal damage in children.

PURPOSE: We studied the relationship among vesicoureteral reflux, urinary tract infection and permanent renal damage in children. MATERIALS AND METHODS: We retrospectively analyzed 303 children younger than 2 years with a first time, nonobstructive, culture verified urinary tract infection. The protocol included ultrasonography and voiding cystourethrography within 3 months after urinary tract infection, and (99m)technetium dimercapto-succinic acid scintigraphy after 1 to 2 years. RESULTS: Vesicoureteral reflux was found in 36 of 163 boys (22%) and in 44 of 140 girls (31%). Of the 303 patients 80 (26%) had permanent renal damage according to dimercapto-succinic acid scintigraphy. The rate of abnormality increased significantly with grade of vesicoureteral reflux in boys and girls. The relative risk of renal damage was significantly increased in patients with vesicoureteral reflux grade II and higher. Maximum C-reactive protein concentration, maximum temperature during urinary tract infection, presence of vesicoureteral reflux and febrile recurrences of urinary tract infection were significantly related to permanent renal damage. In stepwise logistic regression vesicoureteral reflux was the only independent variable for boys, while C-reactive protein and vesicoureteral reflux were independent factors for girls. CONCLUSIONS: There was a significant relationship between grade II vesicoureteral reflux and higher and permanent renal damage in boys and girls. However, while the association between renal damage and vesicoureteral reflux was evident in boys, the role of urinary tract infection and renal inflammation seemed to be equally or more important in girls. These findings support the concept that renal damage is associated with vesicoureteral reflux and is often congenital in boys, while in girls it is more related to urinary tract infection with vesicoureteral reflux as a reinforcing factor.

Uncomplicated duplex kidney and DMSA scintigraphy in children with urinary tract infection.

BACKGROUND: Renal duplication is the most common malformation of the urinary tract and is frequently seen among children with urinary tract infection (UTI). OBJECTIVE: To evaluate problems in the interpretation of dimercaptosuccinic acid (DMSA) scintigraphy and to establish the range of relative function in uncomplicated unilateral duplication. MATERIALS AND METHODS: Retrospective analysis of 303 children less than 2 years of age with first time non-obstructive urinary tract infection investigated by both urography and DMSA scintigraphy. At DMSA scintigraphy, renal lesions and/or relative function below 45% was considered abnormal. Urography was used as reference for the diagnosis of duplication. RESULTS: Duplex kidneys were found in 22 of 303 patients (7%). Of the 16 children with unilateral duplication, 10 had bilaterally undamaged kidneys with a range of relative function varying between 51% and 57% in the duplex kidney. In two of the children with unilateral duplication the imaging results were discordant. CONCLUSION: There was risk of underdiagnosis as well as overdiagnosis of renal damage at scintigraphy. Although it is important to be aware of this risk, the rate of misinterpretation was low. A range of 51% to 57% can be used as the limit for normality of the relative function of a unilateral duplex kidney.