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Purpose: The main criteria used for deciding on surgery in children with presumed antenatally detected pelviureteric junction obstruction (PPUJO) are the level of hydronephrosis (ultrasonography), the level of differential renal function (DRF) and the quality of renal drainage after a furosemide challenge (renography), the importance of each factor being far from generally agreed. Can we predict, on the basis of ultrasound parameters, the patient in whom radionuclide renography can be avoided? Methods: We retrospectively analysed the medical charts of 81 consecutive children with presumed unilateral PPUJO detected antenatally. Ultrasound and renographic studies performed at the same time were compared. Anteroposterior pelvic diameter (APD) and calyceal size were both divided into three levels of dilatation. Parenchymal thickness was considered either normal or significantly decreased. Acquisition of renograms under furosemide stimulation provided quantification of DRF, quality of renal drainage and cortical transit. Results: The percentages of patients with low DRF and poor drainage were significantly higher among those with major hydronephrosis, severe calyceal dilatation or parenchymal thinning. Moreover, impaired cortical transit, which is a major risk factor for functional decline, was seen more frequently among those with very severe calyceal dilatation. However, none of the structural parameters obtained by ultrasound examination was able to predict whether the level of renal function or the quality of drainage was normal or abnormal. Alternatively, an APD <30 mm, a calyceal dilatation of <10 mm and a normal parenchymal thickness were associated with a low probability of decreased renal function or poor renal drainage. Conclusion: In the management strategy of patients with prenatally detected PPUJO, nuclear medicine examinations may be postponed in those with an APD <30 mm, a calyceal dilatation of <10 mm and a normal parenchymal thickness. On the contrary, p, SCOPUS: ar.j, info:eu-repo/semantics/published

Objective: To determine, in children with antenatally detected pelviureteric junction (PUJ) stenosis, what factors may be predictive for deterioration of differential renal function (DRF) in case of conservative treatment or improvement of DRF in case of pyeloplasty. Methods: This study analyzed and compared the initial level of hydronephrosis, DRF, quality of renal drainage, and cortical transit with the late DRF outcome. We reviewed the medical charts of 161 consecutive children with antenatally diagnosed PUJ stenosis during a 10-year period (between 1997 and 2007). From this cohort, we retained 81 children with unilateral PUJ and strictly normal contralateral kidney, with a median follow-up of 67 months. Repeated ultrasounds, voiding cystourethrography, and radionuclide renograms were performed in all children. Results: Fifty patients never underwent a surgical intervention (62%), whereas surgical repair (Anderson-Hynes dismembered pyeloplasty) was performed in 31 (38%). During conservative follow-up, DRF deterioration was observed in 11% of patients. After pyeloplasty, DRF improvement was observed in 25% of patients. Abnormal cortical transit was the only predictive factor of DRF deterioration in case of conservative approach, whereas the initial degree of hydronephrosis, or renal drainage, and the initial DRF level were not predictive. In children who were operated on, only impaired cortical transit was predictive of DRF improvement postoperatively. Conclusion: Conservative management of children with unilateral PUJ stenosis is a safe procedure. Impaired cortical transit although imperfect, seems the best criterion for identifying children for whom pyeloplasty is warranted. © 2013 Elsevier Inc. All Rights Reserved., SCOPUS: ar.j, info:eu-repo/semantics/published

Background The treatment of complicated urinary tract infection in children is still a matter of debate. In our hospital, antimicrobial treatment is initiated intravenously, and the duration of this treatment is adapted according to the results of a Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy. Aim This study was conducted to evaluate retrospectively the frequency and the importance of late renal sequelae when treating intravenously for 7 days those patients with an abnormal acute DMSA. Methods A review was conducted of the medical charts of all patients consecutively admitted between 2005 and 2008 with positive urine culture and clinical and biological evidence of complicated urinary tract infection (UTI). Results There were 144 patients (59 %) with abnormal early DMSA scintigraphy and 98 (41 %) with normal scintigraphy. The median duration of intravenous treatment was 7.0 days in the children with DMSA lesions and 5.0 days in those without lesions. Obvious renal sequelae were observed on late DMSA scintigraphy in 4 (6 %) out of the 65 patients with an abnormal early DMSA who came back for control scintigraphy. Conclusion Sequelae of acute DMSA lesions observed during complicated UTI treated 7 days intravenously were infrequent. Whether the mode and duration of antimicrobial treatment might explain the low rate of sequelae remains to be demonstrated., SCOPUS: ar.j, info:eu-repo/semantics/published

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. © 2012 Springer-Verlag., SCOPUS: cp.j, info:eu-repo/semantics/published

BACKGROUND: Output efficiency (OE) and normalized residual activity (NORA) are two parameters that allow quantifying the renal drainage at any moment of renographic acquisition. Although OE is theoretically more accurate than NORA in case of a decreased overall renal function, both parameters present some weaknesses. OBJECTIVES: To compare both parameters and to evaluate whether the clinical information provided by both parameters is identical. METHODS: From a large database of Tc-99m mercaptoacetyltriglycine 3 renographic studies, 450 kidneys were selected covering a large range of ages, overall function, split function, and quality of drainage. NORA and OE were calculated at the end of the 20-min renogram, as well as on the late post erect postmicturition (PM) views. RESULTS: An inverse correlation was observed between NORA 20 and OE 20 (r=-0.926), as well as between NORA PM and OE PM (r=-0.936). Discrepancies were noted in approximately 10% of the kidneys, but main discrepancies, which would result in a different estimation of the quality of drainage, were only observed in 2% of the kidneys. There was no bias in the discordances; OE could reveal a better as well as a worse quality of drainage than NORA. It is likely therefore that imperfections of both parameters might be the cause of the divergences. The stratification of the kidneys according to age, overall renal function, split function, or quality of drainage did not modify the results. CONCLUSION: NORA, being much easier to program, can replace the output efficiency in the evaluation of renal drainage. © 2011 Wolters Kluwer Health, SCOPUS: ar.j, info:eu-repo/semantics/published

INTRODUCTION: Until recently, renogram, performed in children with pelvi-ureteric junction stenosis detected antenatally, has not been able to predict the probability of function improvement after surgery or the risk of function deterioration in case of conservative attitude. Recently, Schlotmann et al. have suggested that cortical transit might have this predictive role. The aim of this study, focused on those kidneys with severely impaired cortical transit, was to verify this statement. METHODS: All renograms performed in children during a 3-year period (n=729) were retrospectively reviewed and 19 pediatric patients were selected based on an antenatally detected unilateral pelvi-ureteric junction syndrome, the existence of at least two renograms during the follow-up and a severe cortical transit impairment, visually defined. Twenty-six pairs of data could be analyzed and allowed comparing preoperative and postoperative differential renal function (DRF), and the DRF changes during the conservative management. RESULTS: Among the 16 patients who underwent pyeloplasty, 10 showed a significant DRF improvement. Among the 10 patients with conservative follow-up, four showed a significant DRF deterioration. CONCLUSION: Severely impaired cortical transit seems to be a valuable marker of those patients who could benefit from a pyeloplasty, either because of the high probability of postoperative DRF improvement, or because of DRF deterioration in case of an conservative approach. However, a normal cortical transit, as defined in this study, does not exclude the risk of DRF deterioration. Alternatively, the design of this study does not allow excluding the fact that DRF might improve after pyeloplasty despite a normal cortical transit. © 2011 Wolters Kluwer Health, SCOPUS: ar.j, info:eu-repo/semantics/published

In this study we investigated the influence of technical factors (positioning, background (BG) correction and attenuation correction) on qualitative and quantitative (absolute (AU) and relative (RU) uptake) assessment of feline kidneys with 99mtechnetium labelled dimercaptosuccinic acid ( 99mTc-DMSA). Eleven healthy adult cats were included. Influence of BG and depth correction on quantitative assessment was evaluated. Depth correction was based on the geometric mean method (using dorsal and ventral images) and the use of two standards placed over each individual kidney. Visual evaluation showed superiority of dorsal and ventral over lateral positioning due to increased separation of the kidneys permitting region of interest (ROI) placement without overlap. No apparent influence of BG correction was found for RU. However, AU was systematically overestimated without BG correction. Depth correction did not seem to affect RU in most cases, however, in some cats the differences were not negligible. The values for AU without depth correction were lower compared to depth corrected values. © 2011 ISFM and AAFP., SCOPUS: ar.j, info:eu-repo/semantics/published

Objective: Values for output efficiency (OE) and normalized residual activity (NORA) in paediatric patients have been published previously. However, it is now a usual practice to inject furosemide at the beginning of a renogram acquisition (F0 procedure). The aim was to evaluate OE and NORA obtained on F0 renograms, in normal and abnormal paediatric kidneys. Methods: Three groups of kidneys were selected: group 1, normal kidneys (n=155); group 2, dilated but unobstructed kidneys (n=20); and group 3, hydronephrotic kidneys (n=84). A 20-min Tc-mercaptoacetyltriglycine renogram was obtained under early furosemide injection (F0) and was completed by late postmicturition (PM) images. OE and NORA were calculated at the end of the renogram and on the PM images. Results: Group 1: NORA and OE calculated at the end of the F0 renogram revealed better drainage than without F0 stimulation. The PM parameters were comparable with those previously obtained after late furosemide injection (F+20). Group 2: the drainage, despite the early injection of furosemide, was often unsatisfactory at the end of the F0 renogram, but improved dramatically upon the PM acquisition. Group 3: almost normal values up to very abnormal ones were observed. In 35% of kidneys, the values of drainage were out of the range of group 2. Conclusion: Under early furosemide injection, renal drainage in the normal kidneys was better than in basic conditions. In dilated unobstructed kidneys, NORA and OE obtained on late images after micturition were, respectively, below 1.5 and above 80%. © 2010 Lippincott Williams & Wilkins, Inc., SCOPUS: ar.j, info:eu-repo/semantics/published

Estimation of the glomerular filtration rate (GFR) is a useful tool in the evaluation of kidney function in feline medicine. GFR can be determined by measuring the rate of tracer disappearance from the blood, and although these measurements are generally performed by multi-sampling techniques, simplified methods are more convenient in clinical practice. The optimal times for a simplified sampling strategy with two blood samples (2BS) for GFR measurement in cats using plasma 51chromium ethylene diamine tetra-acetic acid (51Cr-EDTA) clearance were investigated. After intravenous administration of 51Cr-EDTA, seven blood samples were obtained in 46 cats (19 euthyroid and 27 hyperthyroid cats, none with previously diagnosed chronic kidney disease (CKD)). The plasma clearance was then calculated from the seven point blood kinetics (7BS) and used for comparison to define the optimal sampling strategy by correlating different pairs of time points to the reference method. Mean GFR estimation for the reference method was 3.7±2.5ml/min/kg (mean±standard deviation (SD)). Several pairs of sampling times were highly correlated with this reference method (r2≥0.980), with the best results when the first sample was taken 30min after tracer injection and the second sample between 198 and 222min after injection; or with the first sample at 36min and the second at 234 or 240min (r2 for both combinations=0.984). Because of the similarity of GFR values obtained with the 2BS method in comparison to the values obtained with the 7BS reference method, the simplified method may offer an alternative for GFR estimation. Although a wide range of GFR values was found in the included group of cats, the applicability should be confirmed in cats suspected of renal disease and with confirmed CKD. Furthermore, although no indications of age-related effect were found in this study, a possible influence of age should be included in future studies. © 2010 ISFM and AAFP., SCOPUS: ar.j, info:eu-repo/semantics/published

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Background: Chronic kidney failure is frequently seen in middle-aged and elderly cats. 51Chromium-ethylene diaminic tetraacetic acid ( 51Cr-EDTA) clearance and single blood sample (SBS) method are used in several species to estimate the glomerular filtration rate (GFR). Hypothesis: The hypothesis of this study was that 51Cr-EDTA clearance could be determined using an SBS method in normal and hyperthyroid cats. Animals: Forty-six cats were included in this study, with an average age of 9.5 years. Of these cats, 27 had hyperthyroidism; 19 were healthy. Methods: After IV injection of 51Cr-EDTA (average dose: 4.25 MBq), 7 blood samples were obtained between 5 and 240 minutes. Reference clearance was calculated in mL/min and mL/min/kg body weight, using a 2-compartment model. Optimal time for clearance measurement with SBS was then determined by systematically comparing each individual plasma concentration to the reference multisample clearance. Results: The average reference plasma clearance of 51Cr-EDTA for all cats was 14.9mL/min (3.7mL/min/kg). The clearance in hyperthyroid cats averaged 16.4mL/min (4.3mL/min/kg) and in normal cats averaged 10.3mL/min (2.4mL/min/ kg).The optimal time for the SBS was 48 minutes after injection of tracer 51Cr-EDTA (R2 = 0.9414), giving the following converting equation: clearance = (0.0066 × DV48 minlltes) - 0.9277 (in mL/min). Conclusions and Clinical Importance: In this study, the single sample 51Cr-EDTA clearance method was used to estimate the global GFR in cats. The method identified differences in clearance between normal and hyperthyroid cats. The optimal time for an SBS was 48 minutes. Copyright © 2008 by the American College of Veterinary Internal Medicine., SCOPUS: ar.j, info:eu-repo/semantics/published

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BACKGROUND: Mean transit time (MTT) within a kidney is given by the integral of the renal activity on a well-corrected renogram between time zero and time t divided by the integral of the plasma activity between zero and t, providing that t is close to infinity. However, as the data acquisition of a renogram is finite, the MTT calculated using this approach might result in the underestimation of the true MTT. To evaluate the degree of this underestimation we conducted a simulation study. METHODS: One thousand renograms were created by convoluting various plasma curves obtained from patients with different renal clearance levels with simulated retentions curves having different shapes and mean transit times. RESULTS: For a 20 min renogram, the calculated MTT started to underestimate the MTT when the MTT was higher than 6 min. The longer the MTT, the greater was the underestimation. Up to a MTT value of 6 min, the error on the MTT estimation is negligible. CONCLUSION: As normal cortical transit is less than 2 min, this approach is used for patients to calculate pixel-to-pixel cortical mean transit time and to create a MTT parametric image without deconvolution. © 2008 Lippincott Williams & Wilkins, Inc., SCOPUS: ar.j, info:eu-repo/semantics/published

BACKGROUND: The slope-intercept method is widely used for the determination of the plasma clearance of Cr-EDTA. When three or more plasma samples are used, the goodness-of-fit (r) can be used as a measure of consistency of the samples. This parameter can not be used, however, if only two samples are available. PURPOSE: To evaluate whether the single-sample technique (SBS) can be used to check the consistency of the slope-intercept method using two blood samples (2BS) in children. METHODS: Simulated computer models of a mono-exponential curve were created in order to represent three children aged 3, 6 and 10 years, each with a large range of clearances values and three distribution volumes, respectively 20%, 25% and 30% of body weight. Errors were then introduced in the injected dose (errors from -50% to +50%) and on the 120 or 240 min blood sample (errors from -50% to +50%). The effects of these errors on the clearance measurement using 2BS and SBS methods were calculated and compared. RESULTS: The errors on the injected dose, the 120 min and 240 min plasma samples introduced errors in the same direction and with the same magnitude on both the SBS and 2BS clearance values. For that reason, the comparison between the SBS methods and the 2BS techniques has a low sensitivity in detecting an eventual error. Striking differences between the SBS method and the 2BS technique were only observed when considerable errors on the injected dose or plasma samples were introduced, particularly in case of a reduced clearance. The comparison between the SBS clearances calculated using the 120 min sample to that obtained using the 240 min samples is slightly more sensitive. However, this approach is also slightly less specific. A difference of more than 10 ml·min·1.73 m can be observed in the absence of an error. CONCLUSIONS: The use of the SBS for checking the consistency of the 2BS constitutes an insensitive approach to detect an eventual error in the injected dose or in the plasma, SCOPUS: ar.j, info:eu-repo/semantics/published

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Vesicoureteric reflux (VUR) is a common finding in pediatric practice that occurs in about 1% of children and is often familial, with several genetical loci probably involved. The majority of low-grade cases have a tendency to resolve spontaneously during childhood. However, VUR has been identified as a risk factor for the development of urinary tract infections (UTI) and is present in a third of young children presenting with this problem. In addition, some children with high-grade VUR have already renal lesions before the advent of any UTI. In a subset of affected individuals, these renal parenchymal lesions are associated with systemic hypertension and chronic renal failure but this risk is considerably smaller than previously assumed. In randomized trials of primary VUR diagnosed after urinary infection, prophylactic antibiotics are equivalent to anti-reflux surgery when subsequent renal lesions and UTIs relapses are used as endpoints. Controlled trials comparing the outcome of renal function in children offered either protocol or immediate treatment at recurrences are desperately lacking. This review article aims to summarize the extensive data regarding this controversial condition, to present rational investigation strategy and to analyze management attitudes in the light of the various lines of practice. © 2006 European Association of Urology and European Board of Urology., SCOPUS: re.j, info:eu-repo/semantics/published

This review should be regarded as an opinion based on personal experience, clinical and experimental studies, and many discussions with colleagues. It covers the main radionuclide procedures for nephro-urological diseases in children. Glomerular filtration rate can be accurately determined using simplified 2- or 1-blood sample plasma clearance methods. Minor controversies related to the technical aspects of these methods concern principally some correction factors, the quality control, and the normal values in children. However, the main problem is the reluctance of the clinician to apply these methods, despite the accuracy and precision that are higher than with the traditional chemical methods. Interesting indications are early detection of renal impairment, hyperfiltration status, and monitoring of nephrotoxic drugs. Cortical scintigraphy is accepted as a highly sensitive technique for the detection of regional lesions. It accurately reflects the histological changes, and the interobserver reproducibility in reporting is high. Potential technical pitfalls should be recognized, such as the normal variants and the difficulty in differentiating acute lesions from permanent ones or acquired lesions from congenital ones. Although dimercaptosuccinic acid scintigraphy seems to play a minor role in the traditional approach to urinary tract infection, recent studies suggest that this examination might influence the treatment of the acute phase, the indication for chemoprophylaxis and micturating cystography, and the duration of follow-up. New technical developments have been applied recently to the renogram: tracers more appropriate to the young child, early injection of furosemide, late postmicturition and gravity-assisted images and, finally, more objective parameters of renal drainage. Pitfalls mainly are related to the interpretation of drainage on images and curves. Dilated uropathies represent the main indication of the renogram, but the impact of this technique on, SCOPUS: re.j, info:eu-repo/semantics/published

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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. Copyright © 2006 Elsevier Inc. All rights reserved., SCOPUS: ar.j, info:eu-repo/semantics/published

BACKGROUND: While the value of the single blood sample (SBS) method for estimating Cr-EDTA plasma clearance has been repeatedly demonstrated, some nuclear medicine physicians are still reluctant to use it because of the lack of quality control parameters. PURPOSE: To present a post-test quality control procedure for the SBS technique in children. METHODS: In addition to the SBS clearance calculated using the specific paediatric SBS method, three artificial slope intercept (ASI) method clearances were calculated by assuming the distribution volume as, respectively, 20%, 25% and 30% of body weight. By dividing the injected activity by the distributional volume, the initial plasma concentrations (A0,30%, A0,25% and A0,20%) were calculated. Using these A0 values and the available single sample, ASI clearances were calculated by using the classical slope-intercept method. The working hypothesis of this approach was as follows. In the absence of significant errors, the three ASI clearance values should be close to that of the SBS method. This hypothesis has been tested using both simulated and patients' data. RESULTS: The results of the simulated study showed that an error in the injected dose produced variable differences between SBS and ASI clearances depending on the clearance values. The effect of an error on the plasma sample also varied as a function of the clearance values. The analysis of patient data revealed that the ASI approach allowed the identification of patients in whom the classical slope-intercept method suggested the presence of a possible error. CONCLUSION: A post-test quality control procedure for the SBS GFR measurement is presented. When the SBS clearance shows a difference with the ASI method (>10 ml·min per 1.73 m), the presence of an error is highly probable. A smaller difference, however, does not exclude erroneous data. © 2006 Lippincott Williams & Wilkins., SCOPUS: ar.j, info:eu-repo/semantics/published

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. © 2005 Elsevier B.V. All rights reserved., SCOPUS: re.j, info:eu-repo/semantics/published

Purpose. The aim of this study was twofold: firstly, to determine whether the European Association of Nuclear Medicine (EANM) dosage card results in weight-independent effective doses or weight-independent count rates; secondly, to determine whether one dosage card is sufficient for 95 different radiopharmaceuticals, and, if not, how many cards we reasonably need to take into account inter-tracer variability. Methods. Normalisation factors for count rate and effective dose were calculated as a function of body weight, with 70 kg as standard. Calculations were performed, using whole-body absorption fractions and MIRDOSE 3 software, for seven anthropomorphic phantoms and ten radionuclides. An analytic function for both relations was proposed. Normalisation factors for effective dose for 95 radiopharmaceuticals were investigated using cluster analysis. Results. Normalisation factors for count rate and effective dose can be estimated accurately as a function of body weight W by (W/70) a holding only one parameter, called the a value. The a values for 95 radiopharmaceuticals were classified into three clusters (n A = 7, nB = 76, nC = 12). Cluster A contains tracers for renal studies. Cluster B contains all remaining tracers, except iodine-labelled tracers for thyroid studies and 89Sr for therapy, which belong to cluster C. Conclusion. Correction factors proposed by the EANM task group mainly correct for effective dose. They are very similar to the factors obtained for cluster A. Using the EANM factors for tracers belonging to clusters B and C results in significantly higher effective doses to children. We suggest using three tracer-dependent dosage cards for which the correction factors have been calculated to obtain weight-independent effective doses. © Springer-Verlag 2004., SCOPUS: ar.j, info:eu-repo/semantics/published

The existence of supranormal differential renal function in unilateral hydronephrosis remains controversial. While some authors consider it as fact, others believe that it is just a technical artifact. Within our department, chromium-51 ethylene diamine tetra-acetic acid (Cr-EDTA) renal clearance is systematically performed in conjunction with technetium-99m mercaptoacetyltriglycine (MAG3) renograms to derive an absolute single kidney glomerular filtration rate (SKGFR). Our data allows us to ascertain whether supranormal differential renal function in unilateral hydronephrosis might be due to hypofunction of the contralateral kidney. Children with marked unilateral hydronephrosis were selected from a large database of MAG3 diuretic(s) renograms. We excluded patients with posterior urethral valves, duplex anomalies, neurogenic bladder, solitary kidney, and those who underwent any previous urological surgery. We also excluded children who had an early furosemide injection (F0 procedure), selecting only those having received furosemide at the end of the renogram (F+20 test). Seventy-three patients (92 renograms) fulfilled these criteria. Differential renal function was calculated using the integral method. Hydronephrotic kidney with a relative uptake ≥55% was defined as supranormal. Six renograms (four patients) demonstrated supranormal relative function on the hydronephrotic side. However, the SKGFR of these kidneys was in all cases within the range of normal values, while the contralateral side demonstrated borderline low SKGFR. Increased relative function on the side of the hydronephrotic kidney is relatively infrequent. When it occurs, it may be related to a borderline hypofunction of the contralateral kidney. © IPNA 2005., SCOPUS: ar.j, info:eu-repo/semantics/published

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Objective: To assess the evolution of individual renal function during the maturation process in terms of single kidney glomerular filtration rate (SKGFR) and split function in children with unilateral complex renal duplication. Study design: We retrospectively reviewed the records of 44 children with unilateral complex duplex kidney. All affected kidneys had a poor or nonfunctioning dysplastic moiety, 28 in the upper pole and 16 in the lower pole. At least 2 radioisotopic examinations, including a 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) renogram and a plasma clearance of 51Cr-ethylenediaminetetraacetic acid (Cr-51 EDTA), were performed in all children, the first one performed at a median age of 3 months (range 2 to 15 months) and the last one at 24 months (range 12 to 120 months). They allowed a precise estimation of split renal function, overall glomerular filtration rate (GFR), and SKGFR. Results: Mean overall kidney GFR increased significantly between the two measurements from 63 ± 12.7 mL/minute/1.73m2 to 95 ± 21 mL/minute/1.73m 2 (P <.0001). SKGFR of the duplex side similarly increased from 26 ± 7.7 mL/minute/1.73m2 to 38 ± 12.6 mL/minute/1.73m2 (P <.0001). In terms of split function, the affected kidney had a remarkable stable function between the two measurements, 40% ± 8.6 and 39% ± 8.3 (P = .94), respectively. However, cases with the lowest initial split function (<30%) had the lowest initial SKGFR and the worst further evolution. Conclusion: In children with unilateral complex renal duplication, we found on the affected side a significant increase of SKGFR because of renal maturation, whereas mean split function remained stable during follow-up. Copyright © 2005 Elsevier Inc. All rights reserved., SCOPUS: ar.j, info:eu-repo/semantics/published

Objective: A drop of split renal function often constitutes a criterion for pyeloplasty in hydronephrosis since it is considered as representing deterioration of the affected kidney. The aim of this work was to determine, in a selected population of patients with a drop of split function of at least 5%, if the evolution of single kidney glomerular filtration rate (SKGFR) was parallel to the one of split renal function. Methods: From a large data basis, we found retrospectively only 29 children (10 below and 19 above two years of age at first examination) having had at least two Tc-99m mertiatide (Tc-99m MAG3) renographic explorations for various urological diseases, with a decrease of split function of at least 5% between the two examinations. Evolution of split function was compared to evolution of SKGFR obtained by means of the combination of Tc-99m MAG3 split function and overall glomerular filtration rate as given by the chromium Cr 51 ethylenediamine tetraacetic acid (EDTA) clearance. Results: For the group above two years of age, SKGFR increased or remained stable in 63% of the cases, while in the children less than 2 years of age, a decrease of SKGFR was never observed, according to the maturation of overall GFR in this age group. Thus, the decrease of split function was not necessarily associated with a similar decrease of SKGFR. Conclusion: In patients with unilateral or bilateral urological disorders, deterioration of split renal function does not necessary correspond to a loss of function of the affected kidney. SKGFR often modifies the interpretation of split function. © 2004 Elsevier B.V. All rights reserved., SCOPUS: ar.j, info:eu-repo/semantics/published

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Functional compensation occurs in a kidney when the function of the contralateral kidney is decreased or absent. What is, however, not documented is the level of unilateral renal impairment at which functional compensation occurs. Split function, as obtained from a radionuclide renogram, can only show the asymmetry between both kidneys. The aim of the present work was to evaluate at what level of unilateral impairment a functional compensation can be observed in the contralateral normal kidney. From a large database, 180 children over 2 years of age with unilateral pathology were retrospectively selected. All of them underwent a radionuclide study, combining a technetium-99m mercaptoacetyltriglycine (Tc-99m MAG3) renogram associated with a chromium-51 ethylenediaminetetraacetic acid (Cr-51 EDTA) overall clearance, allowing a precise estimation of single-kidney glomerular filtration rate (SKGFR). Below 30-35 ml/min/1.73 m2, there was a significant inverse correlation between SKGFR on the normal and the abnormal side. Above this level, no such correlation was observed, the mean SKGFR on the normal side remaining around 58 ml/min/1.73 m2, whatever the value of SKGFR on the abnormal side. In pediatric patients, hyperfunction occurs when SKGFR of the diseased kidney is below 30-35 ml/min/1.73m2. © IPNA 2005., SCOPUS: ar.j, info:eu-repo/semantics/published

Because loss of functional renal mass is compensated by hyperfiltration of remaining tissue, one could hypothesize that a damaged kidney might not have the same rate of maturation as the contralateral one. To verify this, maturation was evaluated in children with asymmetrical renal function during early life. Twenty-five children were selected having had 2 99mTc-MAG3 renograms combined with 51Cr-EDTA clearance measurement, enabling estimation of glomerular filtration rate (GFR), split renal function (SRF), and single kidney GFR (SKGFR). The first test had to be performed before the age of 18 months and SRF on the affected side had to be ≤40%. Moreover, GFR had to increase between the 2 tests by ≥10 mL-1 min/1.73 m2, reflecting maturation due to age. For 18 children SRF changed by between -5% and +5%. For 4 children an increase of ≥5% was observed whereas for the remaining 3 a decrease of ≥5% occurred. For the first 22 kidneys, mean increase of SKGFR was +6.3 mL-1 min/1.73 m2(SD: 6). For the 3 kidneys with ≥5% SRF decrease, SKGFR remained unchanged in 2 (+0.3 and -3 mL min-1/1.73 m2) and increased in the third patient (+15 mL min-1/1.73 m2). In conclusion, renal maturation is comparable in both the malfunctioning kidney and the contralateral normal functioning side. © IPNA 2005., SCOPUS: ar.j, info:eu-repo/semantics/published

Objective: To quantify the influence of overall renal function on normalized residual activity (NORA) and to evaluate the modifying factors. Methods: A computer simulation model generated renograms by convolution of plasma disappearance curves with artificially created retention functions. From a database, 1099mTc-MAG3 plasma curves were selected, corresponding to renal clearances ranging from 33 to 405 ml·min -1. The retention functions had three properties: (1) until the minimal transit time (MinTT), no output and a linear increase in transit time after MinTT; (2) a ratio of MinTT to mean transit time (MTT) equal to 0.3 or 0.8; and (3) a MTT between 3 and 60 min, increasing in steps of 1 min. The model generated 1160 renograms and for each of them the NORA was calculated at 20, 40 and 60 min. For each value of MTT, the coefficient of variation (CV) of the NORA was calculated at 20, 40 and 60 min. Results: For the same retention function, different clearances resulted in different values of NORA. The degree of variability of NORA depended on several factors, including the time of measurement, the MTT and the MinTT to MTT ratio. For clearances between 100 and 400 ml·min-1, the CV of the NORA ranged from 15% to 30%, whilst for clearances below 100 ml·min-1, the CV of the NORA ranged from 22% to 67%. Little influence of the MinTT to MTT ratio was observed. Conclusion: NORA is influenced by overall renal function. The influence is limited for 99mTc mercaptoacetyltriglycine (99mTc-MAG 3) renal clearances over 100 ml·min-1, whilst for clearances less than 100 ml·min-1, the NORA is influenced much more. © 2004 Lippincott Williams & Wilkins., SCOPUS: ar.j, info:eu-repo/semantics/published

SCOPUS: le.j, info:eu-repo/semantics/published

Introduction: It has been suggested that renal retention function can be estimated by differentiation of the Patlak-Rutland plot. Aim: To evaluate the error resulting from this method. Methods: A total of 5800 renograms were generated by convolving real input functions with artificial retention functions. Ten bi-exponential plasma disappearance curves of 99mTc mercaptoacetyltriglycine (99mTc-MAG3) with varying renal clearances served as input functions and 580 retention functions with mean transit time between 3 and 60 min, and variable ratios of minimal to mean transit time served as original retention functions. The retention function was estimated by differentiation of the Patlak-Rutland plot of each renogram. A variant of this retention function was calculated by setting negative values to zero. Results: Minimal transit time was estimated correctly in all cases but the recovered retention function systematically underestimated the original, and negative values were observed. Mean transit time was underestimated with a difference ranging from -22.05 to -0.06 min. By setting the negative values to zero a less important underestimation was observed which ranged from -13.37 to 0.00 min. Maximal transit time was underestimated systematically with a difference ranging from -22.05 to 0.00 min. All differences were influenced by mean transit time, renal clearance and ratio of minimal to mean transit time. Conclusion: Estimation of the renal retention function by differentiation of the Patlak-Rutland plot results in systematic and sometimes important underestimations. By setting the negative values of the recovered retention function equal to zero, important but still partial improvement can be obtained. © 2004 Lippincott Williams & Wilkins., SCOPUS: ar.j, info:eu-repo/semantics/published

Single blood sample methods are widely used for the estimation of the glomerular filtration rate, but the methods recommended for adults are not the same as those for children. The question arises, therefore, as to which method should be used in an adolescent or young adult The aim of this study was to compare the performance of two methods, a specific paediatric converting equation and an adult algorithm, in a group of adolescent and young adult patients. From a large database of 51Cr-ethylenediaminetetraacetic acid (51Cr-EDTA) renal clearance determinations using the two blood sample method, 598 patients, aged 1 week to 90 years, were selected. The results of the 51Cr-EDTA slope intercept clearance of the two blood sample method were used as reference. Using the paediatric algorithm, no bias was observed until the age of 40 years. Then, an increasing positive bias occurred. The standard deviation of the difference was generally less than 4 ml/min until the age of 25 years and increased gradually to reach 7 ml/min at the age of 80 years. Using the Christensen and Groth adult algorithm, the best results were observed in patients older than 50 years. With the exception of children aged less than 5 years, no systematic bias was observed. The standard deviation, however, increased gradually and reached a value of around 8 ml/min in young children. For individuals aged 15-25 years, the mean of the difference between the paediatric algorithm and the slope intercept method was -1.1 ml/min, with a standard deviation of the difference of 3.3 ml/min. For the adult algorithm, the mean of the difference was 0.3 ml/ min, with a standard deviation of the difference of 7.7 ml/ min. It can be concluded that, for individuals aged 15-25 years, both methods performed correctly. In this series, the paediatric method gave better results than the adult algorithm, and its use is therefore recommended. © 2004 Lippincott Williams & Wilkins., SCOPUS: ar.j, info:eu-repo/semantics/published

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Renal transit estimation using renography has been employed for decades. A variety of methods have been developed, ranging from simple quantitative to more sophisticated techniques. In this review, the methods are discussed in perspective of their advantages and drawbacks. Finally, the most robust methods for estimation of renal transit are proposed. © 2004 Lippincott Williams & Wilkins., SCOPUS: re.j, info:eu-repo/semantics/published

SCOPUS: le.j, info:eu-repo/semantics/published

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. © IPNA 2004., SCOPUS: ar.j, info:eu-repo/semantics/published

Purpose: The purpose of this study was to evaluate whether some parameters of the basic renogram allow one to omit the administration of furosemide in cases of hydronephrosis. Materials and Methods: One hundred thirty-seven children (274 kidneys) referred for uni- or bilateral hydronephrosis were evaluated retrospectively. In all children additional furosemide challenges followed by postmicturition views were acquired because of unsatisfactory renal emptying. The patients were categorized into 2 groups according to the residual renal activity on the postmicturition view: those with good emptying (R-) of both kidneys, for which the administration of furosemide was considered of no influence, and those with partial or no emptying of at least 1 kidney (R+). The renogram parameters chosen for predicting R+ and R- were time to maximum (T max), output efficiency at 20 minutes (OE20), and normalized residual activity at 20 minutes (NORA20). For each parameter, the number of children was then calculated, for whom the administration of furosemide could have been omitted. Results: A total of 112 children were categorized as R- and 25 as R+. The cutoff values for 100% negative predictive value of Tmax, OE20, and NORA 20 were 4.5 minutes, 66%, and 1.45 respectively. Application of these cutoff values for the parameters yields, in retrospect, 6 (4%), 29 (21%), and 22 (16%) children respectively for whom administration of furosemide could have been omitted. Conclusion: On the basis of OE20 and NORA 20, the administration of furosemide could have been omitted in a substantial number of patients, despite unsatisfactory renal emptying on the basic renogram., SCOPUS: ar.j, info:eu-repo/semantics/published