99mTc-DTPA Diuretic Renography with 3 hours late output fraction in the evaluation of hydronephrosis in children

ABSTRACT Objective: Dynamic renal scintigraphy complemented by late gravity assisted postvoid images to 60 minutes is a frequently used diagnostic test in the evaluation of hydrone- phrosis. The objective of this study is to evaluate the effectiveness in acquiring images at 180 minutes to calculate the late output fraction (LOF) of 99mTc-DTPA in the diagno- sis of ureteropelvic junction obstruction (UPJO). Materials and Methods: A retrospective study of 177 patients (196 renal units) of sus- pected cases of clinical UPJO was conducted. The patients were submitted to at least two dynamic renal scintigraphies of 99mTc-DTPA, with the addition of furosemide (F0), with a mean age of 4.3±3.8 years for the first study, and a follow-up of 2.7±2.5 years. Results: For diagnosis based on renal curves, a 100% sensitivity, 82.2% specificity, positive predictive value (PPV) of 10.4% and negative predictive value (NPV) of 100% were estimated. For diagnosis based on LOF, a 100% sensitivity, 96.3% specificity, PPV of 35.7% and NPV of 100% were estimated. Conclusion: A LOF <10% is indicative of UPJO, and a LOF ≥15% is indicative of no UPJO. The data demonstrate that LOF presents equivalent sensitivity and NPV, and higher specificity and PPV in comparison to diagnosis based on renal curves, and is useful in the evaluation and follow-up of suspected cases of UPJO.

Renal parenchyma thickness: a rapid estimation of renal function on computed tomography

Purpose: To define the relationship between renal parenchyma thickness (RPT) on computed tomography and renal function on nuclear renography in chronically obstructed renal units (ORUs) and to define a minimal thickness ratio associated with adequate function. Materials and Methods: Twenty-eight consecutive patients undergoing both nuclear renography and CT during a six-month period between 2004 and 2006 were included. All patients that had a diagnosis of unilateral obstruction were included for analysis. RPT was measured in the following manner: The parenchyma thickness at three discrete levels of each kidney was measured using calipers on a CT workstation. The mean of these three measurements was defined as RPT. The renal parenchyma thickness ratio of the ORUs and non-obstructed renal unit (NORUs) was calculated and this was compared to the observed function on Mag-3 lasix Renogram. Results: A total of 28 patients were evaluated. Mean parenchyma thickness was 1.82 cm and 2.25 cm in the ORUs and NORUs, respectively. The mean relative renal function of ORUs was 39 percent. Linear regression analysis comparing renogram function to RPT ratio revealed a correlation coefficient of 0.48 (p < 0.001). The linear regression equation was computed as Renal Function = 0.48 + 0.80 * RPT ratio. A thickness ratio of 0.68 correlated with 20 percent renal function. Conclusion: RPT on computed tomography appears to be a powerful predictor of relative renal function in ORUs. Assessment of RPT is a useful and readily available clinical tool for surgical decision making (renal salvage therapy versus nephrectomy) in patients with ORUs.

Dual-time [99m] TC-MAG3 diuretic renography and new criteria in the assessment of obstructive uropathy

Obstructive pattern within hydronephrotic non-obstructed kidney is frequently encountered during [99m] TCMAG3 diuretic renography. The aim of this study was to assess the value of applying new protocol and criteria on dual-time imaging in ruling out obstruction. We included 53 children [56 kidneys] in this study [28 boys and 25 girls with age range three weeks to 12 years]. All had hydronephrosis, which was bilateral in three children. Eighteen children had pyeloplasty, while 35 children had no previous surgical interventions. All children were referred for assessment of renal outflow obstruction and kidney function. All children underwent routine diuretic [99m]Tc MAG3 renal renography. All had obstructive patterns during diuretic [99m] TcMAG3 renography and underwent a second dynamic study 30 minutes later for 10 minutes. Non obstructive criteria were set as down sloping second time renogram with drop of kidney counts by 50% of peaked activity in first time renogram. Obstructive criteria on dual-time imaging were set as progressive rising second time renogram or flat second time renogram with drop of kidney counts by less than 30% compared to first time study. Equivocal criteria were set as flat renograms with drop of kidney activity by 3 0-50% or down sloping renogram with drop of kidney counts by<30% over 10 minutes. Non obstructive patterns were noticed in 16 kidneys 15 [patients], with down sloping curves during second time renograms in seven kidneys and flat second time renogram with drop of activity by> 50% in 9 kidneys. Obstructive patterns on dual time point [99m] TcMAG3 renography were noticed in 31 kidneys [29 patients]. Eleven kidneys [six patients] were false positive, since three patients had neurogenic bladder with no obstruction, two patients had long standing severe hydronephrosis with no obstruction and one patient had glomerulonephritis. Equivocal patterns were noticed in nine patients, four of them were turned to have significant obstruction, while five had no obstruction. Dual-time [99m] Tc-MAG3 diuretic renography can increase the efficiency in differentiating between obstructed and non-obstructed hydronephrosis compared to routine single time study

outcome of surgical interference in patients with acute obstructive renal failure

To evaluate some of the morphological, functional and clinical impacts of surgical management of acute obstructive renal failure. Thirty six clinically diagnosed patients as having acute obstructive renal failure [22 men 61.1% and 14 women 38.9% ranging in age between 28 and 62 years, mean 45 years] in the period from October 2005 to October 2008. All patients have been evaluated according to the protocol of obstructive uropathy. Clinically most patients presented by anuria 21[58.3%] patients, oliguria 12 [33.33%] patients, loin pain 16 [44.44%] patients, nausea and vomiting 23[63.9%] patients. 30 Patients underwent direct intervention and 6 patients were managed by temporary drainage until improvement of the general condition then definitive surgical procedure. There was a highly significant increase in the incidence of improvement among studied patients.100% [36 patients] out of 36 patients with acute obstructive renal failure showed improvement after surgical intervention. The syndrome of acute renal failure was reversed to a stable renal function that probably represents the preobstructive state of every patient. There was no morbidity or mortality rate in our series if compared with other series dealing with corrective surgery in obstructive renal failure. Surgical correction of acute obstructive renal failure show excellent results, so more efforts must be done for suspected obstruction in acute uremic patients to avoid the dialysis or kidney transplantation

outcome of surgical interference in patients with chronic obstructive renal failure

To evaluate some of the morphological, functional and clinical impacts of surgical management of chronic obstructive renal failure. We will try to assess some of the factors that may predict favorable outcomes. Sixty four clinically diagnosed patients as having chronic obstructive renal failure [41 men 64.1% and 23 women 35.9% ranging in age between 25 and 69 years, mean 47 years] in the period from October 2005 to October 2008. The patients on this study were divided according to past history of renal impairment and/or regular dialysis into two groups as follow: Group [A]: Patients with chronic renal failure with no regular dialysis [36 patients] Males: 26 [72.22%] Females: 10[27.78%]. Group [B]: Patients with chronic renal failure with regular dialysis [28 patients] Males: 18 [64.29%] Females: 10 [35.71%]. All patients have been evaluated according to the protocol of obstructive uropathy. Clinically most patients presented by anuria 17 [26.6%] patients [9 group A and 8 group B], oliguria 24 [37.5%] patients [14 group A and 10 group B], loin pain 42 [65.6%], patients [27 group A and 15 group B], nausea and vomiting 27 [42.2%] patients [8 group A and 19 group B]. 50 Patients underwent direct intervention and 14 patients were managed by temporary drainage until improvement of the general condition then definitive surgical procedure. In our series patients with chronic obstructive renal failure [group A], showed improvement in 31 patients [86.1%] and did not improve in 5 patients [13.9]. Out of the 5 patients who did not improve after management 1 patient [2.8%] remained unchanged and 4 patients [11.1%] continued to have progressive renal failure up to regular dialysis. In patients with chronic obstructive renal failure [group B], renal functions showed different degrees of improvement as follow: In 15 patients [53.6%] good improvement and subsequent complete weaning from dialysis occurred, while in 5 patients [17.8%] there was a decrease in weekly dialysis sessions from 3 to 2 sessions/week. In the remaining 8 patients [28.6%] there was no improvement and patients continued to have regular dialysis as preintervention. The overall complications in this series were [15.6%]. The incidence was much more in the chronic cases group B. The mortality rate in our series is [3.1%] which is not high if compared with other series dealing with corrective surgery in obstructive renal failure. The degree of improvement of renal function found to be correlated to preoperative residual parenchyma thickness, parenchymal echogenicity, corticomedullary differentiation, presenting hemoglobin value and radioisotope GFR. Finally there is evidence of reversibility of renal function after long standing obstruction which provides justification for efforts to identify and treat urinary tract obstruction even if a patient with an obstruction requires dialysis to avoid the dialysis or kidney transplantation or helping patients under dialysis for complete weaning form dialysis or decrease their number of weekly sessions

Clinical follow-up of children with low differential function on diuretic renogram.

OBJECTIVE: One of the most challenging dilemmas in pediatric urology today is to determine the optimal management of children with hydronephrotic kidney secondary to suspected ureteropelvic junction obstruction. Some believe in early surgical management while others believe in conservative management. To better define these issues, the authors retrospectively reviewed 101 patients with hydronephrosis. MATERIAL AND METHOD: The present study was approved by The Children 's Hospital of Philadelphia 's institutional review board and waiver of informed consent for retrospective study. One hundred and one children (72 males and 29 females) of ages of 6 days to 19 years with hydronephrosis with suspected UPJ obstruction underwent diuretic renograms with 99mTc DTPA. The authors classified the differential renal function into three groups: Group I: 0-15%, Group II: 16-30%, and Group III: 31-46%. RESULTS: Forty-one patients with conservative management, 32% (5 in group I: 1 in group II and 7 in group III) showed improved differential renal function. Non-operative management patients from group I and II showed no deteriorating renal function and only one case from group III had deteriorating renal function. In operative management, 78% of group I, 41% of group II, and 25% of group III showed improvement in differential renal function. In the remaining operative cases, six showed deteriorated differential renal function [1 (4%) group I: 3 (18%) group II: 2 (10%) group III] whereas 24 remained stable or unchanged [Group 1: 4 (17%), Group II: 7 (41%), Group 111: 13 (65%)]. CONCLUSION: The authors recommended conservative management for children with differential renal function between 16-46%.

Dificultades en la interpretación del renograma diurético en niños / Difficulties in the interpretation of diuretic renal scintigraphy in childrens

El renograma diurético continúa siendo el estudio funcional de carácter no invasivo de elección en la evaluación de pacientes con hidronefrosis y probable obstrucción pielo-ureteral. Para una adecuada interpretación de éste es esencial dar una meticulosa atención a factores como la preparación previa del paciente, la selección del radiofármaco, la dosis y administración del diurético, la interpretación de las imágenes y el conocimiento de los potenciales errores de la técnica. Para la mayoría de los pacientes el protocolo F+20 es suficiente, sin embargo el protocolo F-15 puede ayudar a clarificar los casos equívocos del protocolo F+20. Las técnicas invasivas como el test de Whitaker son reservadas para aquellos pacientes con hidronefrosis severa o con insuficiencia renal en donde el diagnóstico clínico aún persiste equívoco después de haber efectuado el renograma. Las recientes publicaciones de guías de protocolos estandarizados y consensos internacionales han contribuido a unificar criterios y así mejorar la agudeza diagnóstica y la reproducibilidad de la técnica.

Estimation in adults of the glomerular filtration rate in [99mTc]-DTPA renography - the rate constant method

The purpose of this study was to design an alternative and robust method for estimation of glomerular filtration rate (GFR) in [99mTc]-diethylenetriaminepentaacetic acid ([99mTc] -DTPA renography with a reliability not significantly lower than that of the conventional Gates' method.Methods: The method is based on renographies lasting 40 min in which regions of interest (ROIs) are manually created over selected parts of certain blood pools (e.g. heart, lungs, spleen, and liver). For each ROI the corresponding time-activity curve (TAC) was generated, decay corrected and exposed to a monoexponential fit in the time interval 10 to 40 min postinjection. The rate constant in min-1 of the monoexponential fit was denoted BETA. Following an iterative procedure comprising usually 5-10 manually created ROIs, the monoexponential fit with the maximum rate constant (BETAmax) was used for estimation of GFR.Results: In a patient material of 54 adult subjects in whom GFR was determined with multiple or one sample techniques with [51Cr]-ethylenediaminetetraacetic acid ([51Cr]-EDTA) the regression curve of standard GFR (GFRstd) (i.e. GFR adjusted to 1.73 m2 body surface area) showed a close, non-linear relationship with BETAmax with a correlation coefficient of 95 por ciento. The standard errors of estimate (SEE) were 6.6, 10.6 and 16.8 for GFRstd equal to 30, 60, and 120 ml/(minÀ1.73 m2), respectively. The corresponding SEE values for almost the same patient material using Gates' method were 8.4, 11.9, and 16.8 ml/(minÀ1.73 m2).Conclusions: The alternative rate constant method yields estimates of GFRstd with SEE values equal to or slightly smaller than in Gates' method. The two methods provide statistically uncorrelated estimates of GFRstd. Therefore, pooled estimates of GFRstd can be calculated with SEE values approximately 1.41 times smaller than those mentioned above. The reliabilities of the pooled estimate of GFRstd separately and of the multiple samples method are of the same magnitude. Therefore, [99mTc]-DTPA renography could replace the multiple samples method for GFR determination. In addition, the renography requires fewer resources from patient and staff and offers more clinical results as regards renal uptake function and renal outflow.

Hidronefrosis del recién nacido: cintigrafia renal dinámica con Tc99m MAG3 durante el primer mes de vida / Dynamic renal scintigraphy with Tc99 MAG3 for the diagnosis of newborn hydronephrosis

Background: The early and accurate diagnosis of obstructive uropathy in the newborn, prevents secondary complications and kidney damage. Aim: To study the usefulness of Tc99M MAG3 diuretic renogram in newborns with hydronephrosis. Material and methods : Forty newborns, aged 1 to 30 days, with hydronephrosis, were studied. A Tc99M MAG3 diuretic renogram (DR) was done and its results were compared with clinical features and other imaging studies. Each kidney and its ureter, were considered a renal unit. Results: Seventy six renal units were evaluated. Twenty six were normal on prenatal ultrasound examination and DR. In 11 of the 50 renal units with hydronephrosis, renal function was impaired. Thus, it was impossible to obtain an excretory curve. In 17 of the 39 remaining renal units, the absence of obstructive uropathy was demonstrated clinically. In 16 of these, the DR showed absence of obstruction. In 20 of 21 renal units with confirmed obstructive uropathy, DR showed an obstructive pattern. Conclusions : In newborns, there is an adequate Tc99M MAG3 uptake and diuretic response. Thus, DR becomes a good functional assessment method in newborns with hydronephrosis

Alternative processing of renographic data for use in children and agitated adult patients

The purpose of this study was to describe an alternative method for processing [99mTc]-diethylene-triamine pentaacetate ([99mTc]-DTPA) renographic data which is unaffected by patient movement and which only requires the patient to be on the imaging table during the early and late examination phases. Methods: The analysis is based on early image series (0-2½ min postinjection) and late image series (the last 5 min). Regions of interest (ROIs) over the kidneys, renal parenchyma and renal backgrounds were created in both sets of images. A robust method for determination without deconvolution of mean transit time indices for the whole kidney and renal parenchyma was established. Estimation of renal volume was possible using a geometrical method. Results: Simulation studies and studies in patients showed a close relationship between the mean transit times using deconvolution and the corresponding mean transit time indices. Conclusions: The alternative method is recommended to be applied in those agitated patients, children in particular, where sedation is either contraindicated or not relevant and in cases where the effective acquisition time should be kept at a minimum

Utilidad de la gamagrafía renal con MAG3 en evaluación de disfunción posterior al trasplante / Utility of renal gammagraphy with MAG3 in the evaluation of post transplantation disfunction

La evaluación de riñones trasplantados se puede realizar por medio de la gamagrafía renal con mercaptoacetiltriglicina (MAG3) marcada con tecnecio 99. Tulchinsky y colaboradores diseñaron la escala de severidad de injuria tubular (TISS) (utilizando MAG3) para evaluar la magnitud del compromiso funcional y determinar la posibilidad de recuperación renal. Objetivo: El presente estudio tuvo por objeto aplicar la escala del TISS a pacientes con diagnóstico de disfunción temprana (primeras 72 horas posterior al transplante) para establecer el pronóstico de recuperación; la capacidad de predicción fue evaluada por seguimiento clínico. Lugar del estudio: Fundación Clínica Valle del Lili, Cali - Colombia Materiales y Métodos: Se evaluaron 20 pacientes con sospecha de disfunción temprana, se aplicó la escala de TISS; se clasificaron en dos grupos: aquellos que recuperaron la función y quienes la perdieron. Se cálculo la concordancia entre observadores al aplicar la escala. Resultados: Los pacientes con disfunción temprana se clasificaron así: TISS 1:4, 2:5, 3:4, 4:3, 5:1 y 6:3. Del grupo total, 14 recuperaron la función y 6 perdieron el trasplante; todos los pacientes con TISS 1 evolucionaron a recuperación de la función y los TISS 6 a pérdida renal. Se encontraron mayores pérdidas en pacientes con escala ü a 4: 85 por ciento vs 16por ciento (p= 0.0012). El grado de acuerdo entre observadores al aplicar la escala de TISS fue 90 por ciento y el estadístico kappa del 0.80. Conclusiones: La importancia de la gamagrafía con MAG3 radica no sólo en la utilidad diagnóstica sino pronóstica; ésta última se puede determinar mediante la aplicación de la escala de TISS, sin embargo se requiere validación con un mayor número de pacientes

Medicina nuclear en el diagnóstico de las enfermedades nefrourológicas no obstructivas de los niños / Nuclear medicine in the diagnosis of nonobstructive nephrourologic diseases in children

La medicina nuclear analiza especialmente las funciones de los órganos y sistemas, lo que la hace particularmente útil en el estudio de enfermedades nefrourológicas. Los múltiples radiofármaco existentes en la actualidad permiten medir, individualmente en cada riñón, flujo plasmático renal, filtración glomerular, masa renal funcionante, velocidad de excreción, detectar reflujo vesicoureteral, determinar el volumen residual y evaluar la perfusión sanguínea testicular. Las técnicas de medicina nuclear más empleadas son el cintigrama renal (Tc99m DMSA), el nefrograma (Tc99m DTPA, Tc99m MAG-3, I-131 hipurán) y la cistografía radioisotópica directa o indirecta. El primero se uso para evaluar masa renal funcionante, identificar malformaciones congénitas y cicatrices por pielonefritis. El nefrograma sirve para determinar función renal por separado, detectar hipertensión renovascular (asociado a captopril), evaluar evolución del trasplante renal, identificar malformaciones congénitas y traumatismo. La cistografía isotópica es útil en el seguimiento de pacientes con reflujo debido a la baja dosis de radiación que origina

Síntesis y control del MAG3 99mTc. Estudios comparativos con el hipurán 131I en seres humanos / Syntesis and control of Tc99m MAG3: comparative study with 131I hippuran in humans

La benzoilmercaptoacetiltriglicina (MAG,) se sintetizó de acuerdo con el método de A.R.Fritzberg y colaboradores. Se comprobó su pureza por punto de fusión, composición centesimal, cromatografía líquida de alta presión y resonancia magnética nuclear. Se realizaron estudios farmacológicos, esterilidad, apirogenicidad, toxicidad aguda y distribución biológica en animales. El producto (MAG,) marcado con tecnecio 99m, según la técnica de J.R.Coveney y M.S.Roblins, se controló por cromatografía en papel. Posteriormente, se inyectó en seres humanos (2,5-3 ,Ci) en normales y con patología renal (39 casos totales) realizándose el estudio comparativo con hipurán