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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.

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.

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.

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.

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.

These guidelines on the use of radioiodinated (99m)Tc-MIBG scintigraphy in children, 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 have been influenced by the conclusions of the "Consensus Guidelines for MIBG Scintigraphy" (Paris, November 6, 1997) of the European Neuroblastoma Group and by those of the Oncological Committee of the French Society of Nuclear Medicine. The guidelines should be taken in the context of "good practice" and any local/national rules which apply to nuclear medicine examinations.

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.

The importance of renal clearance in uronephrology has motivated the continuous reassessment of well-established methods and the relentless search for better techniques. Concerning radionuclide methods, data in the current literature confirm the validity of the simplified one-compartment model or the empirical single-sample method for renal clearance measurement, and new algorithms have been described to broaden the application of the techniques to the pediatric population. Based on the same principles, accurate measurement of renal clearance can also be obtained using contrast agents. Using the technique for determination of the glomerular filtration rate during radiographic contrast examination is recommendable. However, potential adverse effects of the contrast substances should be compared with those of other methods before using this technique for measuring renal clearance without scheduled contrast roentgenographic examination. Controversy remains concerning the validity of predicting glomerular filtration rate from plasma creatinine. Although the predicted clearance is correlated with reference clearance, analysis of individual results reveals that important differences of up to 50 mL/min frequently occur.

The aim of the present study was to investigate esophageal motor function by means of krypton-81m esophageal transit scintigraphy and to compare the results with the functional and morphological data obtained by means of triple lumen manometry and endoscopy. In acute and subacute stages of the disease, all clinical, anatomical, and functional parameters were in good agreement, revealing significant impairment. In chronic stages, the severity of the dysphagia was not correlated to the importance of the residual stenosis. Conversely, 81mKr esophageal transit and manometric's findings were in good agreement with the clinical symptoms, during the entire follow-up period ranging between 3 months to 7 years. The 81mKr test is undoubtedly the easiest and probably the most physiological technique currently available for long-term functional evaluation of caustic esophagitis.

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

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.

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.

The aim of the study was to evaluate three different methods for calculating the split renal function in patients with only one functioning kidney, keeping in mind that the split function should be zero on the side of the non-functioning kidney.We retrospectively selected 28 99mTc MAG3 renograms performed in children, 12 with unilateral nephrectomy, 4 with unilateral agenesis and 12 with a non-functioning kidney.A renal and perirenal region of interest (ROI) were delineated around the functioning kidney. The ROIs around the empty kidney were drawn symmetrically to the contralateral side. The split renal function was calculated using three different methods, the integral method, the slope method and the Patlak-Rutland algorithm.For the whole group of 28 kidneys as well as for the three categories of patients, the three methods provided a split function on the side of the non-functioning kidney close to the zero value, regardless of whether the empty kidney was the left or the right one.We recommend the use of the integral method for the whole range of split renal function with 99mTc MAG3. No significant improvement was obtained by means of the more sophisticated Patlak-Rutland method.

This study was designed to evaluate the interobserver variability in reporting on 99mTc-dimercaptosuccinic acid (DMSA) scanning performed 6 mo after an acute episode of pyelonephritis for the detection of late renal sequelae.Forty-six children were selected, who had early and late DMSA studies for evaluation of acute pyelonephritic lesions as well as sequelae. Three observers reported independently and separately on the early and late DMSA scans and, in a second step, on the late scan in the presence of the early scan. Interobserver reproducibility was evaluated for the early DMSA scan, the late DMSA scan alone, and the late DMSA scan with the early scan for comparison.Complete agreement between the three observers was reached in 75%, 78%, and 77% for the early DMSA scan, the late DMSA scan alone, and the late DMSA scan with the early scan for comparison, respectively.Interobserver reproducibility was high and was comparable for both early and late DMSA scintigraphy.

The aim of this study was to compare, in children with acute pyelonephritis, the efficacy of 7 days’ (group A) and 3 days’ (group B) intravenous antibiotics, both followed by an oral treatment. Children were randomized after 3 days of intravenous treatment. Technetium-99m dimercaptosuccinic acid (DMSA) scintigraphy was performed within the first days after admission and repeated 6 months later. Total or partial persistence of renal abnormalities on the 6-month DMSA scintigraphy was used as the endpoint of the study. Among the 92 children included in the study, 87 were followed for at least 6 months (43 in group A and 44 in group B) and were eligible for analysis. Late DMSA was abnormal in 9 kidneys of group A and 12 kidneys of group B, representing respectively 24% and 44% of kidneys with abnormalities on the initial DMSA (difference statistically not significant). When the patients were stratified according to the delay of treatment, the percentage of patients with sequelae in group A was comparable, whether the delay was less or more than 1 week. In group B, the percentage of patients with sequelae was significantly higher (P

The authors describe various patterns of Tc-99m DMSA images that correspond to a diagnosis of acute pyelonephritis. Only those children with complete scintigraphic healing or considerable improvement after 6 months have been considered.

In this retrospective study, the data of bone scintigraphy performed in 21 children suspected of reflex sympathetic dystrophy (RSD) were analyzed. All of them had persistent pain in an extremity or a clinical suspicion of RSD. All children with strong suspicion of RSD showed diffuse hypoactivity at the level of the involved area on bone scintigraphy. This hypoactivity was clearly related to a decreased vascular supply. The specificity of this scintigraphic pattern is questionable, however, since two children without suggestive clinical signs for RSD had the same scintigraphic pattern.

The overall and single-kidney clearance in children with acute urinary tract infection was investigated retrospectively using the combination of the relative 99mTc-dimercaptosuccinic acid (DMSA) uptake and the 51Cr-ethylenediaminetetraacetic acid clearance.There were 180 patients with both normal kidneys, 56 with clear unilateral abnormalities on DMSA scintigraphy and 11 with two abnormal kidneys. Half of the patients were younger than 2 y, and because of the progressive maturation of the renal function, they were not considered in the analysis of the absolute overall and single-kidney clearance; nevertheless, they were included in the analysis of the relative DMSA percentage uptake.When only one kidney was affected on DMSA scintigraphy, the clearance of the affected kidney was lower than on the normal side and often abnormally low. In these unilaterally affected kidneys, contralateral compensation mechanisms tended to occur, resulting in preservation of overall clearance. This compensation was probably not present only on the contralateral side. On the abnormal side, the clearance was normal in about half of the cases, probably because of intrarenal compensation occurring in regions not damaged by the infection. In addition to these compensation mechanisms, hyperfiltration was probably present in many cases of acute urinary tract infection with intact or unilaterally damaged kidneys.

In recent years, *I-MIBG (*I-metaiodobenzylguanidine), which is transported and stored in the chromaffin cells, has been shown to allow good visualization of neuroblastomas in children. This paper deals with 30 *I-MIBG-scans performed in 20 children: 16 with neuroblastoma, 3 with retinoblastoma, and 1 with a malignant paraganglioma. A high detection rate was found for both primary and secondary sites of neuroblastoma. *I-MIBG was generally superior to 99mTc-MDP bone scintigraphy in the detection of bone metastases. Our experience illustrates the unique place of *I-MIBG-scintigraphy compared with other imaging techniques: it makes it possible to define the nature of the tumour, particularly in cases with normal catecholamine levels; to establish how extensive the lesions are at the time of diagnosis; and to confirm complete remission. No abnormal *I-MIBG uptake was noted in the 3 cases of retinoblastoma.

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.In the International Reflux Study the DMSA scintigraphic data showed no difference in outcome between children managed surgically or medically.

Use of technetium-99m labelled mercaptoacetyltriglycine (99mTc-MAG3) simplifies and improves the quantification of renal clearance in children by virtue of its permanent availability, good imaging properties and low radiation exposure. Due to the lack of reference values for 99mTc-MAG3 clearance in children, the Paediatric Task Group of the EANM initiated a multicentre study to evaluate 99mTc-MAG3 clearance values in children with minimal renal disease. One hundred and twenty-five children aged between 12 months and 17 years, classified as renally healthy using defined diagnostic criteria, were included in the study. 99mTc-MAG3 clearance was calculated using an algorithm on the basis of a single blood sample taken at any time between 30 and 40 min after tracer injection. In addition, the absolute 99m-Tc-MAG3 clearance values were normalized to body surface area. For further evaluation the children were classified into several groups according to age. There was a continuous increase in non-corrected 99mTc-MAG3 clearance values from the age of 1 year up to the age of 17 years (mean value2 years: 98+/-57 ml/min; mean value8 years: 208+/-66 ml/min). Normal clearance values for adults were achieved by the age of 8 years. Analysis of the relationship between non-corrected clearance and age yielded a correlation coefficient of r=0.7. When these absolute clearance values were normalized to body surface area, we found nearly constant clearance values for all age groups, with a mean clearance value of 315+/-114 ml/minx1.73 m2. The correlation coefficient for the relationship between normalized clearance and age was r=0.28. In conclusion, the clearance of 99mTc-MAG3 increases continuously throughout childhood into adolescence due to the maturation and growth of the kidney. After normalization of the absolute clearance to body surface area, no correlation between clearance and age could be proven.

This paper is devoted to the practical aspects of pediatric nuclear medicine, particularly the controversy about drug sedation. The authors conclude that drug sedation should be exceptionally used. There is an alternative way, consisting in an adequate approach of the patient: good information to the parents and the child; taking care of the child's environment, starting from the first contacts in the waiting room; specific education of technologists: this includes injections and blood sampling, but also proper handling of the child during the procedure and adequate psychological attitudes toward child and parents. Taking these factors into account, it is exceptional that a test has to be postponed because of the lack of collaboration of the patient; good quality images, using the recommended paediatric amounts of radioactivity can be achieved even for procedures of prolonged duration.

Clinical and experimental observations indicate that the motility of the oesophagus may be affected by emotional stimuli. The aim of this study was to evaluate the incidence of oesophageal contractility impairment in patients suffering from a psychiatric disorder. Fifty-one patients admitted to the psychiatric department were submitted to an oesophageal transit study by means of krypton-81m. All patients with an abnormal oesophageal transit underwent manometry and endoscopy. The level of depression and anxiety was evaluated by the treating psychiatrist, using the Hamilton Depression and Anxiety Rating Scales. The oesophageal transit was abnormal in 13 patients. Two of these 13 patients refused manometric investigation. In ten of the 11 remaining patients, the manometry revealed functional motor abnormalities. Endoscopy, performed in all these ten patients, was normal. In conclusion, a high percentage of oesophageal contractility disturbances was found in psychiatric patients complaining of anxiety and/or depression. These abnormalities were detected by scintigraphy as well as by manometry. Owing to the normal endoscopic findings, these contraction abnormalities are likely to reflect a functional motor impairment.

The aim of this study was to evaluate the variability of the Patlak-Rutland slope as applied to the renal clearance method. We analysed the 99 Tc m -mercaptoacetyltriglycine renograms of 17 non-selected patients (both children and adults, number of kidneys = 34) with a single kidney glomerular filtration rate of 6-73 ml min -1 1.73 m -2 . The acquisition time for the renograms was 20 min with a frame duration of 20 s. First, correction for background activity was introduced using the perirenal area and the size ratio between the kidney and the perirenal area. The Patlak plot was then applied. The first two points were systematically rejected and a series of linear fits calculated from the experimental points, starting from the third point (i.e. 1 min). The final point of the fit never exceeded the time of the peak of the renogram minus one minute (T max - 1) and was always less than 5 min. Although simple visual inspection of the slopes would suggest that the experimental points were distributed accurately along a straight line, it appeared that the slope was strongly dependent on the number of points used for the determination of the fit. As a second step, we restricted the number of points for fitting to the time interval between 1 min and 2 min 40 s. This procedure appeared to show that the Patlak methodology is reliable, giving rise to only small variations in slope, depending on the number of points chosen. However, even in this narrow time interval, significant errors can be made, either because of the very early escape of the radionuclide or because of statistical noise (e.g. in renal failure the signal-to-noise ratio is unfavourable). Therefore, it is advisable, when using this methodology, to restrict the fitting procedure to the second minute of the study and to check visually that this fixed time interval gives rise to a slope that is well adapted to the Patlak plot.

The aim of the present study was to evaluate the accuracy of 99mTc-MAG3 clearance measurements using a precordial gamma camera curve calibrated by a single plasma sample.Technetium-99m-MAG3 was administered to ten young normal volunteers. A 60-min gamma camera acquisition was performed. Five different segments of the gamma camera curve were determined: 3 min to 20 min, 3 min to 30 min, 3 min to 40 min, 3 min to 50 min and 3 min to 60 min. A biexponential function was fitted on each of these five different segments, which were thereafter calibrated using eight different blood samples. These blood samples were successively used for calibration at 5, 10, 15, 20, 30, 40, 50 and 60 min. The single injection, multiple plasma sample method was used as reference.Camera clearances varied markedly based on the length of the precordial curve and on the time of the calibration sample. Different regression equations were obtained for each duration of the camera curve, and for each blood sample timing. Correlation coefficients were0.95 in most cases recording period of at least 50 min, however, was necessary to obtain a s.e.e. better than those obtained using a single blood sample method without gamma camera curve.The 99mTc-MAG3 clearance determination using a gamma camera heart curve calibrated with a single blood sample does not necessarily improve the accuracy of the one blood sample method.

The aim of the present study was to estimate the sensitivity of indirect radionuclide cystography (IRC) performed with technetium-99m mercaptoacetyl-triglycine (MAG3), in comparison with the micturition cystourethrography (MCUG) and direct radionuclide cystography (DRC), for the diagnosis of vesicoureteric reflux. Two groups of patients were selected: group I comprised 40 children who underwent IRC during the acute phase of urinary tract infection and an MCUG 6 weeks later; group II comprised 42 (other) children with known reflux, who underwent IRC and DRC during follow-up. Taking as the reference the total number of refluxing kidneys detected by means of any cystographic technique, 99mTc-MAG3 ICR missed two-thirds of the refluxing kidneys. Most of the small refluxes were missed, but so too were 50% of the major refluxes. Taking as the reference 99mTc dimercaptosuccinic acid (DMSA) scintigraphy, MCUG detected 91% of the patients with DMSA abnormalities on at least one kidney, DRC detected 95%, and IRC detected 46% and 43% respectively, in groups I and II. The use of 99mTc-MAG3 IRC as the sole technique for the detection of vesicoureteric reflux gives rise to an unacceptable number of false-negative results.

Progressive diaphyseal dysplasia (Camurati-Engelmann disease) is a rare hereditary disorder of bone characterized by progressive, bilaterally symmetrical diaphyseal sclerosis of the long bones. Severely affected patients show muscle weakness, waddling gait and severe pain in the extremities. However, clinical and radiological investigations in families with Camurati-Engelmann disease demonstrate a wide variability in expression of the manifestations. Asymptomatic patients were in several instances diagnosed only after radiologic screening of relatives. Although considered an autosomal dominant disorder, families are described where neither clinical nor radiological manifestations can be demonstrated in direct ancestors of patients. Combining roentgenographic examination with bone scintigraphy seems therefore necessary in confirming or ruling out progressive diaphyseal dysplasia in each family member.

The diagnostic work-up of renovascular hypertension is still controversial. The efficacy of renal scintigraphy with technetium-99m diethylene triamine pentaacetate (DTPA) before and after captopril (scintigraphic captopril test) was evaluated in a multicentre study. All 380 hypertensive patients in the study underwent renal arteriography; 125 had renal arterial stenosisor = 70%, and 54 had a technically successful intervention to correct the stenosis. The post-captopril study had a sensitivity of 93% and a specificity of 100% for predicting blood pressure response to intervention, if renal function was normal and a combination of quantitative parameters was applied (individual kidney uptake index40%, time to peak activity2 min or10 min). In the entire population renal artery stenosisor = 70% was detected with a sensitivity of 83% and a specificity of 93% if renal function was normal. In patients with abnormal renal function the performance of the test was worse, owing to a lower specificity which could be increased by using only time parameters. The performance of the test was optimal when the post-captopril findings were examined; no improvement was achieved by evaluation of the changes induced by captopril from the baseline. The test can thus be simplified by performing only a post-captopril study for routine use: a negative test would exclude a curable form of renovascular hypertension in80% and a positive test would predict it in90% of the patients selected for suspicion of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

A multicentre European study was undertaken in order to determine a reasonable algorithm allowing the determination of overall technetium-99m mercaptoacetyltriglycine clearance using a single blood sample. Employing multiple blood sample clearance as a reference method, it was shown that an acceptable estimation of the MAG3 renal clearance could be obtained using a blood sample taken at any time between 30 and 40 min after tracer injection. After correction for body surface area, comparison of clearance determined using (a) the single blood sample and (b) the multiple blood samples provided a coefficient of correlation of 0.949 and an SEE of 27 ml/min. This algorithm is valid for clearance values higher than 100 ml/min/1.73 m2 and for children older than 1 year of age.

Gastroesophageal pH monitoring and reflux scintigraphy were simultaneously performed in 65 children, who were being investigated for suspected gastroesophageal reflux disease. The aim of the study was to compare, peak per peak, the information provided by the two techniques during a 1-h simultaneous-recording period. During this period, 123 reflux episodes were recorded with both techniques, but only six occurred simultaneously. Significantly more reflux episodes were recorded on scintigraphy (n = 88; p less than 0.05), particularly during the first half-hour period (n = 62), if compared with the number of pH drops greater than 1 unit, even at pH levels higher than 4 (n = 41; p less than 0.05). It is concluded that the two techniques explore differently the reflux phenomenon.

A 6-year-old boy presented with an inflammatory syndrome. Because Tc-99m MDP bone scintigraphy revealed increased tracer uptake at the upper pole of the right kidney, further studies were oriented towards a diagnosis of renal or adrenal pathology. I-123 metaiodobenzylguanidine (MIBG) accumulated at the site of the abnormal MDP uptake. The diagnosis of neuroblastoma or allied disorder was excluded on the basis of other investigations and further evaluation, suggesting that the MIBG uptake was a false-positive. Findings on clinical imaging, laboratory findings, Tc-99m DMSA imaging, sonography, and CT scanning were highly suggestive of acute focal pyelonephritis.

Since the early eighties, *I-MIBG (= *I-metaiodobenzylguanidine), which is stored in the neurotransmitter storage granules of chromaffin cells, has been increasingly used for the detection of pheochromocytomas and allied sympathoadrenal pathologies. The aim of this paper is to illustrate, by means of clinical examples, the role of *I-MIBG-scintigraphy in child neuroblastoma and to underline its original place, compared with other imaging techniques, in determining the neuro-ectodermal origin of a tumor as well as in establishing the extension of the lesions at the time of diagnosis and during follow-up.

There is no standard schedule for the amounts of radiopharmaceutical administered to children at present. Various alternative methods are currently in practice, all with some support from the literature. Optimization of the amount of radiopharmaceutical to be administered is discussed in relation to the radiation burden of such an examination. The Paediatric Task Group of the European Association of Nuclear Medicine has investigated the current situation and now suggests a method for standardization of administered amounts of radiopharmaceutical in paediatrics. The fraction of the adult amount of radiopharmaceutical to be administered should be calculated from the child's body weight according to the accompanying table. In small infants, the minimum amount of a radiopharmaceutical is discussed and suggested amounts to be administered are presented.