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OBJECTIVE To discuss the main steps of renographic technique and underline some pitfalls related to the acquisition, processing and interpretation of diuretic renography, an important method for guiding the management of asymptomatic congenital hydronephrosis. METHODS Despite guidelines and consensus protocols, renographic procedures differ among centres, causing difficulties in comparison and controversy in the interpretation of results. Thus we comprehensively assessed published papers on the subject of diuretic renography. RESULTS Differential renal function (DRF) is a robust measure provided there is adequate background subtraction. Pitfalls are related to the drawing of regions of interest, particularly in infants, to estimating the interval during which DRF is calculated, and to an adequate signal-to-noise ratio. There is no definition of a 'significant' reduction in DRF. The classical variables of the diuretic renogram may not allow an estimate of the best drainage. Poor pelvic emptying may be apparent because the bladder is full and because the effect of gravity on drainage is incomplete. Estimating the drainage as residual activity rather than any parameter on the slope might be more adequate, especially if the time of frusemide administration is changed. Renal function and pelvic volume can influence the quality of drainage. Drainage may be better estimated using new tools. CONCLUSION Provided the investigation is standardized and potential pitfalls accounted for, the diuretic renogram provides valuable and reproducible quantitative information on DRF and drainage.

The International Scientific Committee of Radionuclides in Nephro-urology (ISCORN; http://www.iscorn.org) began in the late 1960s as an independent group of physicians and scientists working to facilitate radionuclide renal research and the practice of renal nuclear medicine. This group has subsequently issued a series of Consensus reports and has now developed a Guidance Document for quality assurance and structured reporting of diuresis renography in adults. ISCORN chose diuresis renography for its first Guidance Document for several reasons: suspected obstruction is the most common reason for referral, most radionuclide renal studies are conducted at institutions that perform fewer than 3 studies per week, and a large percentage of radionuclide renal studies are interpreted by physicians with limited training in nuclear medicine. An additional rationale was the observation that diuresis renography reports from ISCORN member institutions showed marked variation in the elements included in the reports as well as considerable variation in how the results were communicated to the referring physicians. Reports that omit the essential components of the procedure, that lack the necessary elements required for quality assurance and interpretation, that fail to indicate the rationale supporting the conclusions, and that fail, in some cases, to even clearly state the conclusions are a disservice to patients and reflect badly on nuclear medicine and radiology. To address these concerns, this Guidance Document was developed through an iterative series of comments and questionnaires regarding the reporting structure and importance of specific elements in the report. Panelists were asked to categorize each element as essential, recommended but not essential, local option (possibly useful but without sufficient data to support a higher ranking), and unnecessary (does not contribute to quality assurance or scan interpretation). Each element was independently scored by panelists without access to the individual scores of the other members or knowledge of the identity of panel members making specific comments. A majority vote was required to place an element in a specific category. The Guidance Document recommends a reporting structure organized into indications, clinical history, study procedure, findings and impression. The Guidance Document also specifies the elements considered essential or recommended in each of the reporting categories and provides a brief discussion of specific elements. Few elements, however, achieved unanimous agreement and the panel recognizes the need for innovation and the possibility of constraints imposed by local circumstances. Consequently, the Guidance Document is not intended to be restrictive but rather to provide a basic structure and rationale for diuresis renography reports in adults so that a report: (1) communicates the results to the referring physician in a clear and concise manner designed to optimize patient care; (2) contains the essential elements required to evaluate and interpret the study; (3)clearly documents the technical components of the study necessary for accountability, quality assurance and reimbursement; and (4) encourages clinical research by facilitating better comparison and extrapolation of results between institutions.

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?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.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 APD30 mm, a calyceal dilatation of10 mm and a normal parenchymal thickness were associated with a low probability of decreased renal function or poor renal drainage.In the management strategy of patients with prenatally detected PPUJO, nuclear medicine examinations may be postponed in those with an APD30 mm, a calyceal dilatation of10 mm and a normal parenchymal thickness. On the contrary, precise estimation of DRF and renal cortical transit should be performed in patients with APD30 mm, major calyceal dilatation and/or parenchymal thinning.

Piepsz, A., Bormans, J., Segers, A., Noterman, J. and Decostre, P. (Departments of Paediatrics, Radioisotopes and Neurosurgery, University Hospital, Brussels, Belgium). Value of brain scanning in pediatric subdural collections. Acta Paediatr Scand, 64:2, 1965.–Eighteen children with subdural collections were submitted to brain scintigraphy. By this method, idopathic and post-traumatic hematomas were detected in 40% of the cases, and subdural effusions in 70% of the cases. No false-negative results were noted in the 3 cases of empyema. Several false-positive images were recorded, most of them following purulent meningitis, without any satisfactory explanation. Neither the technique of scintigraphy used in the department, the dimensions of the skull, the age of hematoma, nor the presence of membranes seemed to affect the accuracy of the method. Compared with the other easily performed examinations (eye fundus, EEG, Echo), scintigraphy still remains important in the diagnosis of subdural collections in children.

These guidelines, which summarise the views of the Paediatric Committee of the European Association of Nuclear Medicine, provide a framework which may prove helpful to nuclear medicine teams in daily practice. They contain information on the indications, acquisition, processing and interpretation of direct radioisotope cystography in children. The guidelines should be taken in the context of "good practice" and any local/national rules which apply to nuclear medicine examinations.

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. 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. 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). 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. 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.

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.

OBJECTIVE This study aims to evaluate interobserver agreement on visual analysis of technetium-99m mercaptoacetyltriglycine (Tc-MAG3) renal tissue transit used for the evaluation of antenatal hydronephrosis. MATERIALS AND METHODS Thirty-eight Tc-MAG3 diuretic renograms were retrospectively collected between 1 and 31 December 2015. The 1-min reframed images were presented to four nuclear medicine consultants and to two nuclear medicine residents, one in the first year of the training program and the others in their fourth and final year. These observers were asked to classify the radiotracer cortical transit (normal/delayed) based solely on visual assessment of the images. For the interobserver agreement, modified Fleiss' kappa (κ) analysis for multiple raters was carried out. For both groups, percentages of agreement were also calculated. RESULTS A total of 69 kidneys were evaluated. All four nuclear medicine consultants agreed on the classification of 88.4% of the kidneys. When the agreement of at least three of the four observers was considered, the percentage of agreement reached 98.6%. The two nuclear medicine residents agreed on the classification of 69.6% of the kidneys. The modified Fleiss' κ-value was 0.88 (95% confidence interval: 0.79-0.95) for the group of nuclear medicine consultants, indicating almost perfect agreement. For the residents, it was 0.39 (95% confidence interval: 0.16-0.59), suggesting fair agreement. CONCLUSION Our results seem to indicate that there is an almost perfect agreement in the qualitative identification of delayed cortical transit among physicians with experience at observing renographic images.

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

Special consideration needs to be given to children who undergo dynamic renography. The Paediatric Committee of the European Association of Nuclear Medicine has updated the previous guidelines. Details are provided on how to manage the child, the equipment, and the acquisition and processing protocols. The pitfalls, difficulties and controversies that are encountered are also discussed, as well as the interpretation of the results.

Under the auspices of the International Atomic Energy Agency, a new-generation, platform-independent, and x86-compatible software package was developed for the analysis of scintigraphic renal dynamic imaging studies. It provides nuclear medicine professionals cost-free access to the most recent developments in the field. The software package is a step forward towards harmonization and standardization. Embedded functionalities render it a suitable tool for education, research, and for receiving distant expert's opinions. Another objective of this effort is to allow introducing clinically useful parameters of drainage, including normalized residual activity and outflow efficiency. Furthermore, it provides an effective teaching tool for young professionals who are being introduced to dynamic kidney studies by selected teaching case studies. The software facilitates a better understanding through practically approaching different variables and settings and their effect on the numerical results. An effort was made to introduce instruments of quality assurance at the various levels of the program's execution, including visual inspection and automatic detection and correction of patient's motion, automatic placement of regions of interest around the kidneys, cortical regions, and placement of reproducible background region on both primary dynamic and on postmicturition studies. The user can calculate the differential renal function through 2 independent methods, the integral or the Rutland-Patlak approaches. Standardized digital reports, storage and retrieval of regions of interest, and built-in database operations allow the generation and tracing of full image reports and of numerical outputs. The software package is undergoing quality assurance procedures to verify the accuracy and the interuser reproducibility with the final aim of launching the program for use by professionals and teaching institutions worldwide.

Cortical 99m Tc DMSA scintigraphy is accepted as a highly sensitive technique for the detection of regional lesions. It reflects accurately 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 to differentiate acute lesions from permanent ones, or acquired lesions from congenital ones. Although DMSA scintgraphy seems to play a minor role in the traditional approach of urinary tract infection, recent studies suggest that this examination might influence the treatment of the acute phase, the indication of chemoprophylaxis and of micturating cystography, as well as the duration of follow-up.

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±2.5 ml/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 30 min after tracer injection and the second sample between 198 and 222 min after injection; or with the first sample at 36 min and the second at 234 or 240 min ( 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.

Objective To evaluate the interobserver reproducibility in reporting on technetium-99m (Tc-99m) dimercaptosuccinic acid (DMSA) scan in children. Methods Sixty Tc-99m-DMSA scans, issued from three centres, were distributed by e-mail to nuclear medicine physicians from the five continents interested in paediatric nuclear medicine. Observers had to choose, for each kidney, among four answers: normal, abnormal, equivocal or poor quality. An additional question was the location of the lesion if any: upper part, mid part, lower part. The responses had to be returned by e-mail. Results Sixty-one observers, with an experience of approximately five or more Tc-99m-DMSA/month, contributed to the study. Median agreement was 93%. The agreement was less than 80% in 29 kidneys (24%) but only in 13% (16 kidneys) was there disagreement between normality and abnormality, the remaining cases being related to 'equivocal' responses. Disagreement was mainly related to the following patterns: (i) normal variants: pear-shaped kidney, hypoactive poles contrasting with important parenchymal mass, triangular kidney, unusual shape of the columns of Bertin; (ii) congenital abnormalities: hydronephrosis, normal duplex kidney; (iii) small defects. Conclusion Interobserver reproducibility can be considered as good among a wide number of observers from the five continents. Disagreement among observers could be reduced by taking the normal variants into account.

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 14.9 mL/min (3.7 mL/min/kg). The clearance in hyperthyroid cats averaged 16.4 mL/min (4.3 mL/min/kg) and in normal cats averaged 10.3 mL/min (2.4 mL/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 minutes) – 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.

This report is the conclusion of the international consensus committee on renal transit time (subcommittee of the International Scientific Committee of Radionuclides in Nephrourology) and provides recommendations on measurement, normal values, and analysis of clinical utility. Transit time is the time that a tracer remains within the kidney or within a part of the kidney (eg, parenchymal transit time). It can be obtained from a dynamic renogram and a vascular input acquired in standardized conditions by a deconvolution process. Alternatively to transit time measurement, simpler indices were proposed, such as time of maximum, normalized residual activity or renal output efficiency. Transit time has been mainly used in urinary obstruction, renal artery stenosis, or renovascular hypertension and renal transplant. Despite a large amount of published data on obstruction, only the value of normal transit is established. The value of delayed transit remains controversial, probably due to lack of a gold standard for obstruction. Transit time measurements are useful to diagnose renovascular hypertension, as are some of the simpler indices. The committee recommends further collaborative trials.

The purpose of this set of guidelines is to help the nuclear medicine practitioner perform a good quality lung isotope scan. The indications for the test are summarised. The different radiopharmaceuticals used for the ventilation and the perfusion studies, the technique for their administration, the dosimetry, the acquisition of the images, the processing and the display of the images are discussed in detail. The issue of whether a perfusion-only lung scan is sufficient or whether a full ventilation-perfusion study is necessary is also addressed. The document contains a comprehensive list of references and some web site addresses which may be of further assistance.

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 samples. Obvious different results obtained by SBS and 2BS or between the SBS calculated using the 120 min and the 240 min samples suggest the presence of an error, but comparable results do not exclude erroneous measurement. Moreover, a difference of more than 10 ml·min·1.73 m can be observed in the absence of an error in the injected dose or in the plasma samples. © 2007 Lippincott Williams & Wilkins, Inc.

We have used 99m Tc-dimercaptosuccinic acid uptake ratio for long-term follow-up of 402 children with moderate to severe vesicoureteral reflux

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.

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/1.73 m2.

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.

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 (99m)Tc-MAG3 renograms combined with (51)Cr-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 beor =40%. Moreover, GFR had to increase between the 2 tests byor =10 mL(-1) min/1.73 m(2), reflecting maturation due to age. For 18 children SRF changed by between -5% and +5%. For 4 children an increase ofor =5% was observed whereas for the remaining 3 a decrease ofor =5% occurred. For the first 22 kidneys, mean increase of SKGFR was +6.3 mL(-1) min/1.73 m(2)(SD: 6). For the 3 kidneys withor =5% SRF decrease, SKGFR remained unchanged in 2 (+0.3 and -3 mL min(-1)/1.73 m(2)) and increased in the third patient (+15 mL min(-1)/1.73 m(2)). In conclusion, renal maturation is comparable in both the malfunctioning kidney and the contralateral normal functioning side.

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.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.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 (nA=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.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.

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.

The split renal function, obtained using Technetium 99m mercaptoacetyltriglycine renography, is currently considered as a robust, accurate and reproducible parameter, provided that it is calculated at a time when no escape of the tracer from the kidney has occurred. The question arises as to whether the simultaneous administration of furosemide with the tracer (F0 test) might accelerate the escape of the tracer, resulting in an underestimation of the split renal function. From a large database, we selected 36 clinically stable children in whom both F0 and F+20 (administration of furosemide 20 min after the tracer) diuretic renography had been performed. In all cases, the F+20 test preceded the F0 test. The mean interval between the two tests was 17 months. The split renal function was calculated on the basis of the 1-2 min background-corrected renal activity using the integral method, slope method and Rutland-Patlak plot. In order to evaluate the effect on the split renal function of an early escape of the tracer, the patients were analysed according to the T(max) value of the renogram for both the F0 and F+20 tests. For the F+20 test, all T(max) values were more than 3 min. For the F0 test, the T(max) value was more than 3 min in 53 kidneys and less than 3 min in 19 kidneys (unilateral in all 19 patients). For the F0 test, for the kidneys with a T(max) value of less than 3 min, there was a tendency to underestimate the split renal function, taking as reference the split renal function observed in the F+20 test. This observation, however, was only statistically significant for the slope method (P=0.03). There was a tendency for lower values with the Rutland-Patlak plot (P=0.07), but, for the integral method, no difference was observed (P=0.5). In conclusion, the simultaneous administration of furosemide with the tracer induces an early acceleration of renal transit. This should be taken into account when calculating the split renal function, for example by favouring the integral method.

The main tool of radionuclide techniques applied to paediatric uro-nephrology is the quantitation of function, which is an information not easily obtained by other diagnostic modalities. The radiation burden is low. Drug sedation is only rarely needed, whatever the age of the patient. Accurate determination of glomerular filtration rate can be obtained by means of an intravenous injection of Cr-51 EDTA and one or two blood samples. Tc-99m DMSA scintigraphy is an accurate method for evaluation of regional cortical impairment during acute pyelonephritis and later on, for detection of permanent scarring. Tc-99m MAG3 renography is nowadays a well-standardized method for accurate estimation of the split renal function and of renal drainage with or without furosemide challenge. This technique is particularly indicated in uni- or bilateral uropathies with or without renal and/or ureteral dilatation. Direct and indirect radionuclide cystography are two alternative modalities for X-ray MCUG. Their relative place in the strategy of management of vesicoureteral reflux is discussed.

Resumen —El proposito de este trabajo fue evaluar tres metodos distintos de calculo de funcion renal relativa (FRR) en pacientes con un solo rinon funcionante, teniendo en cuenta que en el lado del rinon «no funcionante» la funcion debiera ser cero. Pacientes Seleccionamos retrospectivamente 28 renogramas 99mTc MAG3 realizados en ninos: 12 con nefrectomia unilateral, 4 con agenesia unilateral, y 12 con un rinon «no funcionante». Metodo: Se dibujo un area de interes (ROI) renal, y otra de sustraccion de fondo perirrenal, para cada rinon funcionante. Las ROI para el rinon «no funcionante» se dibujaron simetricamente al lado contralateral. La FRR fue calculada usando 3 metodos: Integral, de las Pendientes y Patlak-Rutland. Resultados Tanto para el grupo total de rinones como para cada uno de los tres subgrupos de pacientes, los tres metodos dieron resultados cercanos a cero al lado del rinon «no funcionante», estuviera este al lado izquierdo o derecho. Conclusion Recomendamos el uso del metodo integral para el calculo de amplios rangos de FRR con 99mTc MAG3. Ninguna mejoria significativa fue obtenida por medio del mas sofisticado metodo de Patlak-Rutland.

The feasibility of deconvolution depends on many factors, but the technique cannot provide accurate results if the maximal transit time (MaxTT) is longer than the duration of the acquisition. This study evaluated whether, on the basis of a 20 min renogram, it is possible to predict in which cases the MaxTT will exceed 20 min. Renograms of various shapes were simulated by convolution of a plasma disappearance curve and various created retention functions with a mean transit time (MTT) ranging from 3 to 23 min. The values of MaxTT were then derived from the created curves and compared to three parameters of transit measured on the renograms: the time to reach the maximum of the curve (T-max), the output efficiency at 20 min (OE20), and the normalized residual activity at 20 min (NORA(20))). The proportion of retention functions (n = 390) with MaxTT > 20 min increased with increasing (e.g. 9% for 6 less than or equal to T-max

The aim of this work was to evaluate prospectively the proportion of children with a clinical and biological presentation of acute pyelonephritis, abnormal Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy and negative or equivocal urine cultures. All patients aged 6 weeks to 15 years suspected of acute pyelonephritis (APN) were admitted to the Paediatric Department and underwent Tc-99m DMSA scintigraphy within 3 days after admission and at 6 months. Of 166 patients enrolled in the study, 15 (9%) had negative or equivocal urine culture despite clinical and scintigraphic evidence of APN. Of these 15 children, renal ultrasound was normal in 7 patients and vesicoureteric reflux was found in 9 patients. Control DMSA 6 months after acute episode showed the disappearance of cortical lesions in eight and partial improvement in four patients. In this prospective series, as many as 9% of patients with APN would have been missed on the basis of equivocal or negative urine cultures. It is suggested that Tc-99m DMSA scintigraphy should be performed in children with severe infection without clear aetiology, especially in those with abnormal urinalysis.

Introduction Plasma clearance rate of 51 Cr-EDTA estimated by using one blood sample is commonly used for the calculation of glomerular filtration rate. Aim To estimate the error on single-sample clearance determination induced by errors in sampling time and activity measurement, and to compare it with the error observed on the clearance determination obtained using the slope-intercept method. Methods Forty-five adult patients were chosen from a data base of 51 Cr-EDTA plasma clearance values determined by using two blood samples taken around 2 and 4 h. Patients were selected in such a way as to include clearances from 30 ml.min -1 to 155 ml.min -1 , with steps of 3 ml.min -1 . Based on the slope and the intercept of the slope with the y-axis, the plasma concentration at exactly 2 and 4 h was determined. Normally distributed random errors were then introduced in the sampling time (SD of 0, 1 and 2 min) as well as in the activity measurement (SD of 0,1, 2 and 5%). Then, clearance was calculated using two single-sample methods (i.e. the algorithms of Groth and Tauxe), and the slope-intercept method, which requires two blood samples. For each setting, the simulation was repeated 200 times. The effects on clearance of a random error on the time sampling and/or the activity measurement were then evaluated. Results The error on single-sample clearance induced by a 2 min error in sampling time associated with a 5% error in activity measurement was negligible. For all clearance levels, the SD of the error on the calculated clearance was less than 3.8 ml min-1. Whatever algorithm was chosen, the errors on the single-sample clearance were systematically lower than those observed with the slope-intercept method, for the whole clearance range. Conclusion Errors in sampling time and in activity measurement induced only a very small error on the single-sample EDTA clearance, which is systematically lower compared to that observed on the slope-intercept method using two blood samples.

Output efficiency (OE) has been proposed as an objective tool for the estimation of renal emptying. The aim of this paper was to evaluate some factors that may affect the value of this parameter obtained by a 99Tcm MAG3 renogram. In 22 patients, the effect of different types of renal background correction was calculated. In 10 patients, simultaneous gamma camera renography and multiple blood sampling allowed the error of using a heart curve instead of a plasma curve to be evaluated. Finally, an evaluation was carried out on the effect of neglecting the change of plasma activity between the end of the furosemide acquisition and the post-micturition view obtained after repositioning of the patient on the gamma camera: 142 patients who had had multiple blood sampling were retrospectively selected for that purpose. It has been shown that all these factors may significantly affect the value of OE, particularly in cases with poor renal drainage. Unless standardization of the procedure is introduced for some of these factors, the cut-off levels for good, fair and poor drainage may vary between centres.

A questionnaire related to cortical scintigraphy in children with urinary tract infection was submitted to 30 experts. A wide consensus was reached on several issues related to planar images: 99m Tc dimercapto succinic acid (DMSA) appears as the most appropriate tracer for renal imaging; dynamic tracers are considered to be inferior, in particular 99m Tc diethylenetriaminepentaacetate, which is not recommended. The general opinion is that DMSA scintigraphy is not feasible with a minimal dose below 15 MBq, whereas the maximum dose should not be higher than 110 MBq. The dose schedule generally is based on body surface area, and sedation is only exceptionally given to children. Images are obtained 2 to 3 hours after injection, preferably with high resolution collimators; pinhole images are used by only half of the experts. Posterior and posterior oblique views are used by most of the experts, and the posterior view is acquired in supine positions. At least 200.000 kcounts or 5 minute acquisition is required for nonzoomed images. As a quality control, experts check the presence of blurred or double outlines on the DMSA images. Color images are not used and experts report on film or directly on the computer screen. As far as normal DMSA images are concerned, most experts agree on several normal variants. Hydronephrosis is not a contraindication for DMSA scintigraphy but constitutes a pitfall. Differential renal function generally is measured, but no consensus is reached whether or not background should be subtracted. Most of the experts consider 45% as the lowest normal value. A consensus is reached on some scintigraphic aspects that are likely to improve and on some others that probably represent persistent sequelae. There is a wide consensus for the systematic use of DMSA scintigraphy for detection of renal sequelae, whereas only 58% of the experts are systematically performing this examination during the acute phase of infection.

Among all the physiological indices that can be quantified using renography, measurement of renal function is the most basic. These measurements are used to make critical clinical management decisions and, as such, their reliability needs to be quality assured. This article seeks to address each aspect of the renography procedure, with particular emphasis on the effect on measurement of relative renal function. Estimation of individual kidney function is mentioned, but only briefly. A consensus approach was adopted, overseen, and directed by a chairman appointed by the Scientific Committee of the International Radionuclides in Nephro-Urology Group. The chairman selected the panel of experts from eight different countries based on their practical experience in the field. Where evidence exists to support the various recommendations it is given. Otherwise, the stated guidance represents the considered opinion of a body of experts, based on long experience and unpublished data. Some necessary compromises were made to account for the fact that renography is seldom performed solely with the purpose of measuring relative renal function. The technicalities of renography have always been a source of debate in nuclear medicine, which is reflected by the fact that a consensus could simply not be reached on a small number of issues. The structure of the report ensures that these are clearly indicated. This should serve to highlight gaps in our current knowledge, thus helping to direct future research. It is envisaged that the recommendations will be revised on a 2-year cycle to ensure that they remain up to date. An "open" process will be used to encourage participation and ownership. It is hoped that promotion of these guidelines, suitably complemented by audit processes, will raise standards in the practice of gamma camera renography.

The aim of this study was to evaluate renal function during the acute phase of symptomatic urinary tract infection and the changes observed several months later. Overall glomerular filtration rate (GFR) as well as single kidney GFR (SKGFR) were calculated using the combination of a left/right uptake ratio obtained from technetium 99m-dimercaptosuccinic acid (DMSA) scintigraphy and 51chromium-EDTA plasma clearance. Forty-four patients with obvious unilateral or bilateral DMSA abnormalities were studied. In patients with unilateral lesions, both the overall GFR and the SKGFR were significantly higher during the acute phase of infection than several months later, on the abnormal side as well as the normal side. The relative percentage uptake was lower on the abnormal side than the normal side, obviously due to loss of functional parenchyma. This percentage increased significantly during the recovery phase, reflecting the total or partial healing of the renal lesions, despite the decrease of the corresponding SKGFR. However, during both the acute and the recovery phase, the relative percentage uptake of the abnormal kidney was in the normal range and often close to 50%. In patients with bilateral lesions, no significant changes were observed between the acute phase and the recovery phase.

The results of serial dimercaptosuccinic acid (DMSA) imaging over 5 years are reported in 287 children with severe vesico-ureteral reflux entered into the European Branch of the International Reflux Study in Children. The children were randomly allocated to medical (n=147) or surgical (n=140) management and DMSA studies were performed during the follow up period at least 6 months after any urinary tract infection. Abnormal images were classified into four types: (1) large polar hypodensity with normal renal outline; (2) peripheral photon deficient defect(s) in a non-deformed kidney; (3) small renal image with normal contour; and (4) peripheral defect(s) with resultant irregularity of the renal outline. The DMSA findings were abnormal at entry in 235 (82%) with no difference in incidence or severity between the two treatment groups. During follow up, deterioration was observed in 25 medically and 23 surgically treated patients and comprised image deterioration alone in 17, image deterioration with corresponding reduction in differential function in 16 and reduction in relative function without image change in 15, with similar distribution between the two treatment groups. Deterioration was more frequent in children entering the study under the age of 2 years and in those with grade IV rather than grade III reflux. These findings, showing no difference in outcome between children managed surgically or medically, are consistent with the radiological results already published.

To evaluate inter- and intra-observer reproducibility of renographic quantitative parameters of input and output in children.100 children with unilateral or bilateral uropathy were selected, aiming to cover the entire range of ages, overall glomerular filtration rate (GFR), differential renal function (DRF) and quality of drainage. Renograms were acquired and processed according to the EANM guidelines, using a non-commercial software. Following parameters were tested: DRF using integral and Patlak methods, normalized residual activity (NORA) and output efficiency (OE) at 20 min and on the late post-erect post-micturition acquisition. Three observers from the same department and one from Santiago (Chile) processed independently the 100 renograms using the same renal software. Two observers reprocessed the 100 renograms again two months later in order to evaluate the intra-observer reproducibility.No significant difference was observed between the four observers, whatever the considered parameter of input function or output. For left DRF (Integral and Patlak methods), 95% of the individual differences were between -5% and +5 %. They were between -0.5 and +0.5 units for both NORA 20 and NORA PM, and between -10% and +10% for OE 20 and OE PM. Inter-and intra- observer reproducibility were comparable. Outliers tended to be more frequent for Patlak than for Integral. Very low GFR (20 mL/min/1.73 m(2)), very young age (first days of life), huge megaureters, NORA values higher than 2.0, OE values below 60% and bladder in the renal background area (ectopic kidney) were the main characteristics of extreme differences.

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.

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.