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Background: In people, extrarenal pelvis is a normal anatomical variant, characterized by the protusion of the pelvis out of the renal hilum, which can be associated with other anomalies, or predispose to stasis or infection. While other diagnostic imaging methods provide anatomical and morphological information about the kidney, scintigraphy allows to determine the renal function and has greater sensitivity in the detection of functional alterations. The aim of this work is to report the case of an asymptomatic cat diagnosed with extrarenal pelvis detected by scintigraphy, which presented alterations in laboratory and renal imaging tests, and absence of associated obstructive process. Case: A 7-year-old mixed-breed female cat was evaluated for a routine health assessment at the Veterinary Teaching Hospital of the Federal University of Rio Grande do Sul (HCV-UFRGS). When performing the imaging and laboratory tests, renal alterations compatible with chronic kidney disease were found in the abdominal ultrasonography examination and in serum creatinine levels. Therefore, it was decided to perform scintigraphy evaluation to better assess renal function. Dynamic renal scintigraphy with 99mTcDTPA revealed an evident concentration of the radiotracer in the left kidney with effective elimination only after the diuretic stimulus. The right kidney exhibited less concentration of the radiotracer but showed effective elimination before the diuretic stimulus. Image analysis suggested the presence of an extrarenal pelvis on the left side. The relative renal uptake was 68% for the left kidney and 32% for the right kidney. The glomerular filtration rate was 1.65 mL/min/kg. Static renal scintigraphy with 99mTcDMSA revealed irregularity in the distribution of the radiotracer in both kidneys, showing less activity in the caudal pole of the left kidney. The right kidney was apparently reduced and with less activity, especially in the medial portion. The relative renal uptake was 65% for the left kidney and 35% for right kidney, while the absolute renal uptake of the left kidney was 33% and that of the right kidney was 17%. The alteration described in the left kidney, in correlation with dynamic renal scintigraphy, suggested an aspect of lower activity in the caudal pole due to the presence of activity in the extrarenal pelvis. The left kidney was classified as presenting normal renal function and there was moderate to severe deficit of renal function on the right side. Discussion: Chronic kidney disease may be present before clinical signs and biochemical abnormalities are identified. In this report, the animal was referred for a routine evaluation and showed no clinical signs nor alterations on physical examination. However, as renal morphological alterations were seen on ultrasonography and the cat presented mild azotemia, it was decided to perform two renal scintigraphy exams. Despite the radiotracer elimination from the left kidney was seen only after the diuretic stimulus, dynamic renal scintigraphy did not show any obstructive process. This delay on elimination was probably a result of the anatomical variant called extrarenal pelvis. In the static renal scintigraphy, it was possible to evaluate morphological changes in the kidneys and suggest less activity in the caudal pole of the left kidney, due to the presence of activity in the extrarenal pelvis, apparently causing the mentioned defect. The correct diagnosis of morphological changes is essential and for this purpose the best combination of imaging tests is necessary. Renal scintigraphy was fundamental, in this case, for the diagnosis of extrarenal pelvis in one of the kidneys, an abnormality not reported in the feline species within the literature researched by the authors. In addition, renal scintigraphy helped to guide the clinical management of the patient described in this report.

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OBJECTIVE: The purpose of this study was to determine whether unenhanced MRI without sedation is a feasible substitute for dimercaptosuccinic acid (DMSA) scintigraphy in the detection of renal scars in pediatric patients. SUBJECTS AND METHODS: Patients scheduled for 99mTc-labeled DMSA scintigraphy for assessment of possible renal scars were recruited to undergo unenhanced MRI (free-breathing fat-suppressed T2-weighted single-shot turbo spin-echo and T1-weighted gradient-echo imaging, 13 minutes' total imaging time). Scintigraphic and MRI studies were evaluated by two independent blinded specialty-based radiologists. For each imaging examination, readers identified scars in upper, middle, and lower kidney zones and rated their diagnostic confidence and the quality of each study. The scintigraphic readers' consensus score opinion for the presence of scars was considered the reference standard. RESULTS: DMSA scintigraphy showed scarring in 19 of the 78 (24.4%) evaluated zones and MRI in 18 of the 78 (23.1%). The two MRI readers found mean sensitivities of 94.7% and 89.5%, identical specificities of 100%, and diagnostic accuracies of 98.7% and 97.4%. Interobserver agreement was 98.7% for MRI and 92.3% for DMSA scintigraphy. The MRI readers were significantly more confident in determining the absence rather than the presence of scars (p = 0.02). MRI readers were more likely to rate study quality as excellent (84.6%) than were the scintigraphic readers (57.7%) (p = 0.024). CONCLUSION: Unenhanced MRI has excellent sensitivity, specificity, diagnostic accuracy, and interobserver agreement for detecting renal scars in older children who do not need sedation. It may serve as a substitute modality, especially when DMSA is not available.

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Introducción: la infección de las vías urinarias es una causa importante de morbilidad infantil. Establecer si existe pielonefritis aguda es un factor importante para su tratamiento. Materiales y métodos: estudio observacional descriptivo. Se registraron los resultados de uroanálisis, gram de orina y urocultivo de niños entre 3 meses y 5 años de edad hospitalizados con sospecha de infección de las vías urinarias, entre enero de 2008 y diciembre de 2010. En pacientes con urocultivo positivo se evaluó el resultado de la gammagrafía renal, estimando la incidencia de pielonefritis aguda. Resultados: se recolectaron 1.463 historias clínicas y se solicitó urocultivo en 237. De estas, el 54,4% fueron positivas para pielonefritis. En 93 casos se tomaron gammagrafías renales, positivas en el 59,1% de los casos. Conclusiones: la incidencia de pielonefritis aguda en pacientes con infección de las vías urinarias se confirmó en el 59,1%.

Introduction: Urinary tract infection is a major cause of child morbidity. The diagnosis of acute pyelonephritis is important to decide the treatment. Methods: Retrospective observational study. We collected information of urinalysis, urine Gram and urine culture of hospitalized children between 3 months and 5 years old, with suspected urinary tract infection between January 2008 and December 2010. In patients with positive urine culture, the results of renal scintigraphy (Gamma scan) were evaluated to estimate the incidence of acute pyelonephritis. Results: We identified 1,463 medical records. Urinary culture was obtained in 237 patients, of whom 54.4% were positive. Renal scintigraphy was obtained in 93 of these patients and 59.1% were positive. Conclusions: The incidence of acute pyelonephritis in patients with confirmed urinary tract infection was 59.1%.

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OBJECTIVE: To investigate the influence of bladder fullness on the diagnosis of urinary tract obstruction during dynamic renal scintigraphy with a diuretic stimulator. MATERIALS AND METHODS: We studied 82 kidneys in 82 patients submitted to dynamic renal scintigraphy with a diuretic stimulator. We compared the proportional elimination of the radiopharmaceutical 99mTc-DTPA from the kidneys before and after bladder emptying in post-diuretic images, classifying each image as representing an obstructed, indeterminate, or unobstructed kidney. RESULTS: The overall elimination of 99mTc-DTPA from the kidneys was 10.4% greater after bladder emptying than before. When the analysis was performed with a full bladder, we classified 40 kidneys as obstructed, 16 as indeterminate, and 26 as unobstructed. When the 40 kidneys classified as obstructed were analyzed after voiding, 11 were reclassified as indeterminate and 3 were reclassified as unobstructed. Of the 16 kidneys classified as indeterminate on the full-bladder images, 13 were reclassified as unobstructed after voiding. CONCLUSION: In dynamic renal scintigraphy with a diuretic stimulator, it is important to obtain images after voiding, in order to perform a reliable analysis of the proportional excretion of 99mTc-DTPA from the kidneys, avoiding possible false-positive results for urinary tract obstruction.

OBJETIVO: Verificar a influência da repleção vesical no diagnóstico da obstrução do trato urinário durante a cintilografia renal dinâmica com estímulo de diurético. MATERIAIS E MÉTODOS: Foram estudados, retrospectivamente, 82 rins de 82 pacientes submetidos a cintilografia renal dinâmica. Compararam-se as porcentagens de excreção do radiofármaco DTPA-99mTc pelos rins antes e após o esvaziamento vesical nas imagens pós-diurético, classificando-os como obstruídos, indeterminados ou não obstruídos. RESULTADOS: A avaliação da excreção do radiofármaco pelos rins mostrou que houve aumento de 10,4% na taxa de excreção global quando a bexiga foi esvaziada. Dos 82 rins estudados, 40 foram considerados obstruídos, 16 indeterminados e 26 como não obstruídos, na análise com a bexiga repleta. Na análise das imagens após micção, dos 40 classificados como obstruídos, 11 passaram a ser classificados como indeterminados e 3 como não obstruídos. Além disso, dos 16 rins apontados como indeterminados nas imagens com a bexiga repleta, 13 passaram a ser considerados não obstruídos com a bexiga vazia. CONCLUSÃO: É fundamental uma imagem após a micção na cintilografia renal dinâmica para uma análise fidedigna da porcentagem de excreção do radiofármaco pelo rim, evitando-se possíveis falso-positivos para obstrução do trato urinário.

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Abstract Objective: To investigate the influence of bladder fullness on the diagnosis of urinary tract obstruction during dynamic renal scintigraphy with a diuretic stimulator. Materials and methods: We studied 82 kidneys in 82 patients submitted to dynamic renal scintigraphy with a diuretic stimulator. We compared the proportional elimination of the radiopharmaceutical 99mTc-DTPA from the kidneys before and after bladder emptying in post-diuretic images, classifying each image as representing an obstructed, indeterminate, or unobstructed kidney. Results: The overall elimination of 99mTc-DTPA from the kidneys was 10.4% greater after bladder emptying than before. When the analysis was performed with a full bladder, we classified 40 kidneys as obstructed, 16 as indeterminate, and 26 as unobstructed. When the 40 kidneys classified as obstructed were analyzed after voiding, 11 were reclassified as indeterminate and 3 were reclassified as unobstructed. Of the 16 kidneys classified as indeterminate on the full-bladder images, 13 were reclassified as unobstructed after voiding. Conclusion: In dynamic renal scintigraphy with a diuretic stimulator, it is important to obtain images after voiding, in order to perform a reliable analysis of the proportional excretion of 99mTc-DTPA from the kidneys, avoiding possible false-positive results for urinary tract obstruction.

Resumo Objetivo: Verificar a influência da repleção vesical no diagnóstico da obstrução do trato urinário durante a cintilografia renal dinâmica com estímulo de diurético. Materiais e métodos: Foram estudados, retrospectivamente, 82 rins de 82 pacientes submetidos a cintilografia renal dinâmica. Compararam-se as porcentagens de excreção do radiofármaco DTPA-99mTc pelos rins antes e após o esvaziamento vesical nas imagens pós-diurético, classificando-os como obstruídos, indeterminados ou não obstruídos. Resultados: A avaliação da excreção do radiofármaco pelos rins mostrou que houve aumento de 10,4% na taxa de excreção global quando a bexiga foi esvaziada. Dos 82 rins estudados, 40 foram considerados obstruídos, 16 indeterminados e 26 como não obstruídos, na análise com a bexiga repleta. Na análise das imagens após micção, dos 40 classificados como obstruídos, 11 passaram a ser classificados como indeterminados e 3 como não obstruídos. Além disso, dos 16 rins apontados como indeterminados nas imagens com a bexiga repleta, 13 passaram a ser considerados não obstruídos com a bexiga vazia. Conclusão: É fundamental uma imagem após a micção na cintilografia renal dinâmica para uma análise fidedigna da porcentagem de excreção do radiofármaco pelo rim, evitando-se possíveis falso-positivos para obstrução do trato urinário.

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Introducción: la infección del tracto urinario es una de las infecciones bacterianas más frecuentes en la infancia. Objetivos: conocer las alteraciones renales en la fase aguda de la primera infección febril del tracto urinario, y relacionarlas con las variables estudiadas. Métodos: se estudiaron 211 niños con diagnóstico microbiológico de primera infección febril del tracto urinario, a los cuales se les realizó gammagrafía renal con Tc-DMSA en la fase aguda de la infección. Los resultados de la gammagrafía se correlacionaron con la duración e intensidad de la fiebre antes del diagnóstico, los reactantes de la fase aguda (hemograma, eritrosedimentación y proteína C reactiva) y los resultados de los estudios imaginológicos (ultrasonido renal y uretrocistografía miccional). Resultados: predominó el sexo femenino y el 82,4 % de los pacientes fueron menores de un año. El 54 % de los pacientes presentaron alteraciones gammagráficas, y el patrón de hipocaptación del radiofármaco fue el hallazgo que predominó en el 70 % de ellos. Se encontró asociación significativa al relacionar la duración e intensidad de la fiebre con las alteraciones renales. De los parámetros de laboratorio, la leucocitosis superior a 15 000, la eritrosedimentación acelerada y la proteína C reactiva elevada, tuvieron significación estadística con las alteraciones renales, y los hallazgos radiológicos detectados por el ultrasonido renal y uretrocistografía miccional se correlacionaron estadísticamente con la afectación renal detectada con la gammagrafía. Conclusiones: un porcentaje elevado de los pacientes presentó extensión de la infección al parénquima renal, y las variables clínicas, de laboratorio e imaginológicas estudiadas fueron parámetros orientadores de daño renal.

Introduction: the urinary tract infection is one of the most frequent bacterial infections in the childhood. Objectives: to learn about the acute renal alterations in the first febrile urinary tract infection, and to relate them to the studied variables. Methods: two hundred eleven children diagnosed as first febrile urinary tract infection patients were studied and performed Tc-DMSA renal scintigraphy in the acute phase of infection. The results were correlated to the duration and intensity of the fever before the diagnosis, to the acute phase reactants (hemogram, erythrosedimentation and reactive-C protein) and to the results of imaging studies (renal ultrasound and mictional uretrocystography). Results: females prevailed and 82.4 % of patients were under one year-old. In the study group, 54 % presented with scintigraphic alterations and the hypocapture pattern of the radiopharmaceutical was the predominant finding in 70 % of patients. There was significant association between the duration and intensity of the fever, and the renal alterations. Regarding the lab parameters, leukocytosis above 15 000, accelerated erythrosedimentation and raised reactive-C protein were statistically significant and related to the renal alterations, whereas the radiological findings observed in renal ultrasound and mictional urethrocystography were statistically correlated to the renal lesion detected in the scintigraphy. Conclusions: high percentage of patients suffered the spread of infection over the renal parenchyma; additionally the studied clinical, lab and imaging variables indicated renal injure.

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Objective: This study evaluates the diagnostic value of Renal Doppler Ultrasound (RDU) in the diagnosis of acute renal involvement among children admitted for a first febrile urinary tract infection (UTI), compared to a Renal Scintigraphy (RS). Methodology: All children admitted during 2009 for a first febrile UTI and positive urinary culture were prospectively studied. All received a RDU and RS with Tc99di-mercaptosuccinic acid during the first 72 hours of hospitalization. Image evaluation was performed blindly. RS was considered to be the gold standard to identify renal involvement. Results: The protocol was completed in 54 children (90 percent). RDU was altered in 36 (66 percent), and RS in 42 (78 percent) of children. Both exams coincided in 78 percent of the children, and in 81 percent of the kidneys. Sensitivity and specificity of RDU for these patients was 78,6 percent and 75 percent (72 percent and 89,6 percent per kidney), respectively. Negative predictive value was 50 percent. RDU detected significantly fewer defects in the left kidney, (p = 0,0026), especially if the defect was localized in the upper pole, and in absence of other associated scintigraphic abnormalities (p = 0,0001). Children with scintigraphic renal involvement showed significant more alterations during the acute phase. Conclusions: RDU is sensitive and specific to detect renal involvement in a child admitted for a febrile UTI, but has a low negative predictive value. Therefore, a negative ultrasound in a patient with inflammatory signs should be confirmed through a scintigraphy, since there are certain sites that are difficult to localize in a sonogram, such as the left superior pole.

Introducción: El objetivo del presente estudio fue evaluar las propiedades diagnósticas de la ecografía renal con Doppler (ERD) en la identificación del compromiso renal agudo, en una cohorte de niños hospitalizados con primera infección urinaria (ITU) febril y compararlas con el cintigrama renal estático (CR). Metodología: Durante el año 2009, en forma prospectiva, se estudiaron todos los niños hospitalizados con primera ITU febril y con urocultivo positivo. En todos ellos se realizó una ERD y un CR con ácido dimercapto succínico marcado con tecnecio 99, dentro de las primeras 72 horas de hospitalización. Los estudios de imágenes fueron realizados en forma ciega, por operadores independientes. El CR se consideró como gold standard para la identificación de compromiso renal. Resultados: En 54 niños (90 por ciento de los elegibles) hospitalizados por ITU febril se cumplió el protocolo de estudio imageneológico. La ERD estuvo alterada en 36 (66 por ciento) y el CR en 42 (78 por ciento) de los niños. Ambos exámenes fueron coincidentes en 78 por ciento de los niños y en 81 por ciento de los riñones estudiados. La sensibilidad y especificidad del la ERD para estos pacientes fueron de 78,6 por ciento y 75 por ciento (72 por ciento y 89,6 por ciento al analizarlo por unida renal), respectivamente, y el valor predictivo negativo de 50 por ciento. La ERD pesquisó significativamente menos defectos cuando éstos eran exclusivos del riñón izquierdo (p = 0,0026), especialmente si el defecto se localizó en el polo superior y en ausencia de otras alteraciones cintigráficas asociadas (p = 0,0001). Los niños con compromiso renal cintigráfico tenían significativamente más alterados los reactantes de fase aguda. Conclusiones: La ERD en un niño hospitalizado por una ITU febril tiene alta sensibilidad y especificidad para pesquisar el compromiso renal, pero un bajo valor predictivo negativo; por lo tanto, si la ERD es negativa y el paciente presenta parámetros inflamatorios alterados, el compromiso renal debe ser confirmado por un CR, ya que existe evidencia de ciertas localizaciones más difíciles de identificar por la ERD, como aquellas que afectan el polo superior izquierdo.

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INTRODUCCIÓN. La infección del tracto urinario es una de las infecciones bacterianas más frecuentes en la infancia. El objetivo de esta investigación fue conocer las alteraciones renales en la fase aguda de la primera infección febril del tracto urinario. MÉTODOS. Se estudiaron 90 niños con diagnóstico microbiológico de primera infección febril del tracto urinario, a los cuales se les realizó gammagrafía renal con Tc DMSA en la fase aguda de la infección. Los resultados de la gammagrafía se correlacionaron con la duración e intensidad de la fiebre antes del diagnóstico, los reactantes de la fase aguda (hemograma, ritrosedimentación y proteína C reactiva [PCR]) y los resultados de los estudios radiológicos (ultrasonido renal y uretrocistografía miccional). RESULTADOS. Predominó el sexo femenino y el 84,4 por ciento de los pacientes fueron menores de 1 año. El 59 por ciento de los pacientes presentaron alteraciones gammagráficas y el patrón de hipocaptación del radiofármaco fue el hallazgo que predominó en el 75,5 por ciento de éstos. No se encontró asociación significativa al relacionar la duración e intensidad de la fiebre con las alteraciones renales. De los parámetros de laboratorio solo la PCR tuvo significación estadística con las alteraciones renales y los hallazgos radiológicos detectados por el ultrasonido renal y uretrocistografía miccional no se correlacionaron estadísticamente con la afectación renal detectada con la gammagrafía renal.CONCLUSIONES. Un porcentaje elevado de los pacientes presentó extensión de la infección al parénquima renal y la PCR fue el único parámetro orientador de daño renal

INTRODUCTION. Urinary tract infection (UTI) is one of the more frequent bacterial infections in childhood. The aim of present research was to know the acute phase renal alterations of the first febrile infection of urinary tract. METHODS. Ninety children with a microbiological diagnosis of first febrile infection of urinary tract were studied and a renal Tc DMSA scintigraphy was done in the acute phase of infection. Scintigraphy results were correlated with the fever length and intensity before diagnosis, acute phase reactants (hemogram, erythrosedimentation and C reactive protein (CRP) and the radiological studies results (renal US and urination urethrocystography). RESULTS. There was a female sex predominance and the 84,4 percent of patients were under 1 year. The 59 percent of patients had scintigraphy alterations and the radiodrug hypocaptation pattern was the predominant finding in the 75,5 percent of them. There was not a significant association between the fever length and intensity and the renal alterations. From the laboratory parameters only the RCP was statistically significant with renal alterations and the radiologic findings detected by renal US and urination urethrocystography had not statistic correlation with the renal affection detected by renal scintigraphy. CONCLUSIONS. A high percentage of patients had an extensive infection to renal parenchyma and the CRP was the only guiding parameter of renal damage

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Objetivo: Comparar la utilidad del CRE en etapa aguda versus el CRE diferido para predecir la presencia y/o ausencia de RVU en niños con primer episodio de ITU febril. Material y métodos: Estudio retrospectivo donde se analizaron 95 pacientes con primer episodio deITU febril, a los cuales se les realizó dentro de los primeros 15 días de evolución del cuadro un CRE control y luego un CRE diferido después de 6 meses del primer episodio. Se correlacionó la presencia de alteración cintigráfica en el CRE agudo y en el CRE diferido con la existencia RVU diagnosticado mediante UCG. Resultados: La edad promedio fue de 17 meses, con 72 (75,8 por ciento) pacientes menores de 2 años de edad. Cuarenta y nueve pacientes eran de sexo femenino. Se encontró RVU en 41 de los 95 pacientes (43,2 por ciento). En la etapa aguda 93,7 por ciento de los pacientes tuvo un CRE alterado, 46,1 por ciento de los cuales tenía RVU. Ninguno de los 6 pacientes con CRE normal tuvo RVU (VPN de 100 por ciento). En el CRE diferido persistieron con alteraciones cintigráficas el 40,4 por ciento de los niños, de los cuales la mitad presentaba RVU. De los 59 niños sin alteraciones cintigráficas el 61 por ciento no tenía RVU (VPN 60 por ciento).Conclusión: El CRE diferido no es un buen predictor de RVU en niños con primer episodio de ITU febril, a diferencia del CRE realizado en etapa aguda, el cual tiene un excelente VPN para RVU.

Objective: To compare the usefulness of static renal scintigraphy done in the acute phase of febrile UTI versus late static renal scintigraphy to predicit the presence and/or absence of VUR in children with first episode of febrile UTI. Materials and methods: Retrospective study that analized 95 patients with first episode of febrile UTI, to whom a control static renal scintigraphy was done in the first 15 days of the UTI and then late static renal scintigraphy was performed after 6 months of the first episode of UTI. A correlation was made between the presence of scintigraphic abnormalities in the acute phase static renal scintigraphy and late static renal scintigraphy with the existence of VUR diagnosed by VUG. Results: The mean age was 17 months, with 72 (75.8 percent) patients younger than 2 years. Forty-nine patients were girls. VUR was found in 41 of the 95 patients (43.2 percent). In the acute phase 93.7 percent of the patients had an abnormal static renal scintigraphy, 46.1 percent of which had VUR. None of the 6 patients with a normal static renal scintigraphy had VUR (NVP de 100 percent). In the late static renal scintigraphy 40.4 percent of the patients persisted with scintigraphic alterations, the presence of VUR in this group of patients was of 50 percent. Of the 59 patients without scintigraphic abnormalities 61 percent did not have VUR (PPV 60 percent).Conclusion: The late static renal scintigraphy is not a good predictor of VUR in children with first episode of febrile UTI, unlike the static renal scintigraphy done in the acute phase of the illness, which has an excelent NPV for VUR.

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