Utilidad de los parámetros analíticos en el manejo de los pacientes pediátricos con sospecha de pielonefritis aguda. ¿Es fiable la procalcitonina? / Usefulness of analytical parameters in the management of paediatric patients with suspicion of acute pyelonephritis. Is procalcitonin reliable?

Objetivo. Valorar la utilidad de la procalcitonina (PCT) y de otros parámetros analíticos (leucocitos en sangre, proteína C reactiva [PCR]) como indicadores de daño renal agudo en niños tras su primer episodio de infección del tracto urinario febril o afebril (ITU). Material y métodos. Se ha realizado un estudio retrospectivo, con obtención de medidas séricas de PCT, PCR y leucocitos en pacientes pediátricos admitidos entre enero de 2009 y diciembre de 2011, con un primer episodio de ITU, objetivando el daño renal agudo mediante gammagrafía renal con 99mTc-DMSA (DMSA) en las primeras 72h después de la admisión. Se ha llevado a cabo un estudio descriptivo de la muestra y un trazado de curvas ROC con cálculo de puntos de corte óptimos para cada parámetro. Resultados. Se han incluido 101 pacientes divididos en 2 grupos en función del resultado del DMSA, 64 fueron diagnosticados de pielonefritis aguda (PNA) y 37 de ITU. Las medias de leucocitos en sangre, PCR y PCT fueron significativamente mayores en pacientes con PNA respecto a aquellos con DMSA normal. El área bajo la curva ROC fue de 0,862 para la PCR, 0,774 para leucocitos en sangre y 0,731 para la PCT. El punto de corte óptimo para la PCT fue 0,285ng/ml (sensibilidad 71,4% y especificidad 75%). Conclusión. Si bien los niveles medios de fiebre, leucocitos, PCR y PCT estuvieron significativamente más elevados en pacientes con PNA que en los que tenían ITU, la sensibilidad y especificidad de estos parámetros analíticos no permiten predecir la existencia de afectación renal aguda, haciendo imprescindible la realización de una gammagrafía renal con DMSA (AU)

Objective. To investigate the usefulness of procalcitonin (PCT) and other analytical parameters (white blood cell count [WBC], C-reactive protein [CRP]) as markers of acute renal damage in children after a first febrile or afebrile urinary tract infection (UTI). Methods. A retrospective study was conducted on children with a first episode of UTI admitted between January 2009 to December 2011, and in whom serum PCT, CRP and white blood cell count were measured, as well as assessing the acute renal damage with renal scintigraphy with 99mTc-DMSA (DMSA) within the first 72h after referral. A descriptive study was performed and ROC curves were plotted, with optimal cut-off points calculated for each parameter. Results. The 101 enrolled patients were divided into two groups according to DMSA scintigraphy results, with 64 patients being classified with acute pyelonephritis (APN), and 37 with UTI. The mean WBC, CRP and PCT values were significantly higher in patients with APN with respect to normal acute DMSA. The area under the ROC curve was 0.862 for PCR, 0.774 for WBC, and 0.731 for PCT. The optimum statistical cut-off value for PCT was 0.285ng/ml (sensitivity 71.4% and specificity 75%). Conclusion. Although the mean levels of fever, WBC, CRP, and PCT were significantly increased in patients with APN than in those who had UTI, the sensitivity and specificity of these analytical parameters are unable to predict the existence of acute renal damage, making the contribution by renal DMSA scintigraphy essential (AU)

Computing quantitative indicators of structural renal damage in pediatric DMSA scans.

OBJECTIVES: The proposal and implementation of a computational framework for the quantification of structural renal damage from 99mTc-dimercaptosuccinic acid (DMSA) scans. The aim of this work is to propose, implement, and validate a computational framework for the quantification of structural renal damage from DMSA scans and in an observer-independent manner. MATERIALS AND METHODS: From a set of 16 pediatric DMSA-positive scans and 16 matched controls and using both expert-guided and automatic approaches, a set of image-derived quantitative indicators was computed based on the relative size, intensity and histogram distribution of the lesion. A correlation analysis was conducted in order to investigate the association of these indicators with other clinical data of interest in this scenario, including C-reactive protein (CRP), white cell count, vesicoureteral reflux, fever, relative perfusion, and the presence of renal sequelae in a 6-month follow-up DMSA scan. RESULTS: A fully automatic lesion detection and segmentation system was able to successfully classify DMSA-positive from negative scans (AUC=0.92, sensitivity=81% and specificity=94%). The image-computed relative size of the lesion correlated with the presence of fever and CRP levels (p<0.05), and a measurement derived from the distribution histogram of the lesion obtained significant performance results in the detection of permanent renal damage (AUC=0.86, sensitivity=100% and specificity=75%). CONCLUSIONS: The proposal and implementation of a computational framework for the quantification of structural renal damage from DMSA scans showed a promising potential to complement visual diagnosis and non-imaging indicators.

Evaluation of a crossed fused renal ectopia in a paediatric patient using 99mTc-DMSA SPECT/CT / Ectopia renal cruzada con fusión en un paciente pediátrico evaluado con 99mTc-DMSA SPECT/TC

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Litotricia extracorpórea en niños. Eficacia y evaluación a largo plazo de la lesión del parénquima renal mediante gammagrafía con DMSA-99mTc / Extracorporeal lithotripsy in children - The efficacy and long-term evaluation of renal parenchyma damage by DMSA-99mTc scintigraphy

Objetivo: determinar la eficacia de la litotricia extracorpórea por ondas de choque (LEOC) y los posibles efectos nocivos en el parénquima renal de niños sometidos a tratamiento de la litiasis renal mediante gammagrafía renal con ácido dimercaptosuccínico marcado con 99mTc (DMSA-99mTc). Pacientes y métodos: desde enero de 2004 a noviembre de 2007 se sometió a 18 niños (de 3-10 años) a LEOC (Philips-Dornier) por urolitiasis renal. A todos los pacientes se les realizó una evaluación preoperatoria, que incluyó una exploración física, cultivo de orina, pruebas de imagen y gammagrafía renal con DMSA-99mTc. La evaluación tras el tratamiento constó de una exploración clínica, determinación de la presión arterial, cultivo de orina, ecografía renal y DMSA-99mTC, repetidas a los 3, 6 y 12 meses, que se compararon con las exploraciones obtenidas antes de la LEOC para determinar posibles cambios morfológicos o funcionales. Resultados: se fragmentaron con éxito los cálculos en todos los casos; en 9 pacientes (50%) con una sesión de LEOC, en 6 (33%) con dos sesiones y en tres pacientes (17 %) con tres sesiones de LEOC. Sólo un paciente (5%) mostró un cambio de tamaño del riñón derecho con descenso de la función tubular, sin hipertensión ni otros cambios importantes después de tres sesiones de LEOC y 6 meses de seguimiento. En los demás casos se comprobó la ausencia de hipertensión hasta los 12 meses de seguimiento, de hematomas en la ecografía o de cicatrices renales importantes en las exploraciones gammagráficas. Conclusión: la LEOC es eficaz y segura para tratar la litiasis renal en niños. Pueden aparecer lesiones del parénquima renal precozmente tras el tratamiento, pero estas lesiones son pasajeras y se resuelven espontáneamente en prácticamente todos los casos. No existen generalmente lesiones renales irreversibles asociadas con la LEOC, ni siquiera después del periodo de seguimiento con exploración clínica y ecográfica y gammagrafía con DMSA-99mTc(AU)

Purpose: To determine the effectiveness of extracorporeal shock-wave lithotripsy (ESWL) and possible deleterious effects on renal parenchyma of children subjected to treatment of renal lithiasis, using renal scintigraphy with 99mTc dimercapto-succunic acid (DMSA). Patients and methods: From January 2004 to November 2007, 18 children (age 3-10 years) underwent ESWL (Philips-Dornier) for kidney urolithiasis. All patients underwent preoperative evaluation, including physical examination, urine culture, image exams and renal scintigraphy with Tc99-DMSA. Evaluation after treatment consisted of a clinical examination, blood pressure measurement, urine culture, renal ultrasound and Tc99- DMSA, repeated at 3, 6 and 12 months, which were compared to the scans obtained before ESWL to determine possible morphological or functional changes. Results: Success in the stones fragmentation was achieved in all cases – in 9 patients (50%) with one session of ESWL, in 6 (33%) with two sessions and in 3 patients (17%) with 3 sessions of ESWL. Only one patient (5%), after three sessions of ESWL and 6 months of follow-up showed change in size of right kidney with a decrease in tubular function, without hypertension or other major changes. In the other cases, there was absence of hypertension up to 12 months of follow-up, absence of renal hematomas detected by ultrasound or significant renal scars in scintigraphic examinations. Conclusion: ESWL is effective and safe for treating renal lithiasis in children. Renal parenchyma lesions may occur early after treatment, but these lesions are transients and resolve spontaneously in virtually all cases; generally, there are no irreversible renal lesions associated with ESWL, even after the follow-up period with clinical examination, ultrasound examination and 99mTc-DMSA scintigraphy(AU)

Adsorption of radiopharmaceuticals to syringes: setting up a reliable protocol for its assessment.

BACKGROUND: It is well known that various drugs, including radiopharmaceuticals, may adsorb to plastic syringes to different extents. Some reports suggest that adsorption can reach levels of almost 50%. The consequence of adsorption of a radiopharmaceutical and subsequent inadequate dosing can include an inappropriate diagnostic response in patients, an increase in the duration of investigation or treatment, and an increase in cost. AIM: To investigate the extent of adsorption of Tc-succimer to plastic syringes and to set up a reliable protocol for assessment of the extent of retention of drugs to single-use plastic syringes before a new syringe brand and/or radiopharmaceutical are introduced in a nuclear medicine department. METHODS: Radiopharmaceutical kits from two different manufacturers were compared for retention using syringes from three different producers. To assess the influence of dilution on retention, Tc-succimer preparations were further diluted with sodium chloride solution for injection. Syringes were filled to one-third of their capacity and incubated at room temperature before being emptied into vacuum vials. The radioactivity of the syringes was measured before and after emptying. The extent of retained radioactivity was calculated as a percentage of radioactivity in the syringe before emptying. RESULTS: Results show that adsorption of Tc-succimer considerably differs between syringe brands. The adsorption of undiluted Tc-succimer in 30 min may exceed 50%. CONCLUSION: The findings show that measurement of retention in syringes and injection sets should be regarded as an essential aspect of quality assurance before radiopharmaceuticals, syringes and injection sets are used routinely.

In vivo radionuclide uptake quantification using a multi-pinhole SPECT system to predict renal function in small animals.

PURPOSE: In vivo quantification of radiopharmaceuticals has great potential as a tool in developing new drugs. We investigated the accuracy of in vivo quantification with multi-pinhole single-photon emission computed tomography (SPECT) in rats. METHODS: Fifteen male Lewis rats with different stages of renal dysfunction were injected with 50 MBq 99mTc-dimercaptosuccinic acid. Four to six hours after injection, SPECT of the kidneys was acquired with a new four-headed multi-pinhole collimator camera. Immediately after imaging the rats were sacrificed and the kidneys were counted in a gamma-counter to determine the absorbed activity. SPECT data were reconstructed iteratively and regions of interest (ROIs) were drawn manually. The absolute activity in the ROIs was determined. RESULTS: Uptake values ranging from 0.71% to 21.87% of the injected activity were measured. A very strong linear correlation was found between the determined activity in vivo and ex vivo (r2=0.946; slope m=1.059). CONCLUSION: Quantification in vivo using this multi-pinhole SPECT system is highly accurate.

Paper chromatographic and paper elettrophoretic study of the solution chemistry of Tc-99m-methylendiphosphonate and of Tc-99m-dimercaptosuccinate for improving the tumour-affinity of Tc-99m during scintigraphic imaging of cancer.

In order to find the conditions under which Tc-99m-methylenediphosphonate (Tc-99m-MDP) and Tc-99m(V)-dimercaptosuccinate (Tc-99m(V)-DMSA) may become tumour-seeking agents, leaving healthy organs free from the radionuclide uptake, the solution chemistry of these radiopharmaceuticals was studied by paper chromatography and paper electrophoresis in distilled water, in physiological saline, in NAHCO3, and ascorbic acid solutions. Both radiopharmaceuticals are anionic in the radiopharmaceutical solution but get easily hydrolysed to form cationic Tc-99m species which concentrates in healthy bone and in some bone metastases. Tc-99m (V)-DMSA being more stable remains long in the blood pool giving undesirable presence of the radionuclide in lung, heart and kidneys, in addition to its reduced uptake in bone metastases and in some primaries. We are trying to eliminate these drawbacks of healthy organ uptake of Tc-99-m(V)-DMSA not only to get a clean scintigraphic image of the tumour with this radiopharmaceutical but to extend its formulation, thus obtained, to prepare radiopharmaceutical with Re-188, which is the higher homologue of Tc-99m, for systemic therapy of cancer. Essentially similar solution chemistry of both radiopharmaceuticals suggests that like Tc-99m-MDP, technetium-99m-dimercaptosuccinate is also a complex of tetravalent Tc-99m and not of pentavalent Tc-99m as so far supposed to be.

Quantitative autoradiography using a radioimager based on a multiwire proportional chamber.

Determination of the biodistribution of radiopharmaceuticals is an important issue for the evaluation of their performance in diagnosis and therapy. In this study, we evaluated a digital radioimager (RI) based on a multiwire proportional chamber for quantitative autoradiography (AR). The RI allows direct detection of electronic emissions of gamma emitters. Its qualitative and quantitative performances were tested on 99mTc and (111)In labelled sections and compared with conventional film AR. Linearity of count rate versus activity was verified over a 104 range of activity. As compared with film AR, a substantial improvement of the detection limit was obtained even for acquisition periods up to 20 times less than film exposure times. We provided the basis for quantitative analysis with tissue equivalent paste standards: the 99mTc and (111)In RI counting efficiencies were respectively 1.19% and 2.35%. We illustrated the respective values of RI and film AR in two rat studies: 99mTc-DMSA in kidney and dual-isotope 99mTc-MIBI and (111)In-antimyosin in heart. Calculated activity concentrations on sections of rat organs confirmed good correlation to gamma counting (deviation less than 12%). We suggest RI as a convenient technique for fast localization of single or dual-isotope tracers and determination of activity distribution.