ABSTRACT
Objetivo Evaluar las diferentes características diagnósticas de la función renal relativa (FRR) y de la función renal relativa normalizada por volumen renal relativo (FRRN), con el fin de analizar la posible mejora diagnóstica que implicaría su uso conjunto. Métodos Hemos estudiado con 99mTc-DMSA 952 unidades renales (riñones individuales), que pertenecían a 476 pacientes pediátricos (269 niñas) de edades comprendidas entre 0 y 11 años. De ellas, 355 unidades renales se consideraron patológicas a partir del análisis visual gammagráfico. Se determinaron los puntos de corte más apropiados para establecer los valores normales de las funciones FRR y FRRN, considerando como patrón de referencia al análisis visual gammagráfico. Se realizaron curvas ROC y se calculó el índice J de Youden y la exactitud para diferentes puntos de corte desde 42 por ciento hasta 50 por ciento, tanto para la FRR como para la FRRN. Se realizó también un análisis bayesiano (global y parcial clasificando las unidades renales por indicaciones clínicas) de la FRR y la FRRN. Resultados Para la FRR el mejor punto de corte fue 45 por ciento y para la FRRN fue 47 por ciento. El análisis bayesiano global mostró mejores resultados de los diferentes parámetros estadísticos para la FRRN. El análisis bayesiano parcial indicaba un importante incremento de la sensibilidad en pacientes con patología de dilatación de vía: de 10 por ciento (FRR) a 74.6 por ciento (FRRN); y con pielonefritis aguda: de 29.2 por ciento (FRR) a 66.2 por ciento (FRRN) mientras que en pacientes con nefropatías crónicas la sensibilidad fue similar (70.1 por ciento). Conclusión El cálculo de la FRRN (punto de corte 47 por ciento) proporciona información útil y complementaria a la FRR, ya que cuantifica la calidad relativa del riñón independientemente del volumen renal y refleja mejor los hallazgos gammagráficos.
Purpose To assess the different diagnostic features of relative renal function (RRF) and volume normalized relative renal function (NRRF) with the aim of analysing the possible diagnostic improvement that would imply their joint use. Methods We studied 952 kidneys with 99mTc-DMSA, belonging to 476 paediatric patients (269 girls) aged 0-11 years. 355 out of total were considered pathologic (visual analysis). The most appropriate cut-off points for establishing normality of RRF and NRRF were determined, considering as gold standard the visual scintigraphic analysis. R.O.C. curves were performed, J Youden index and accuracy were calculated for the different cut-off points from 42 percent to 50 percent for RRF and NRRF. A bayesian analysis (global and partial according to clinical indications) of RRF and NRRF was also performed. Results For RRF the better cut-off point was 45 percent and for NRRF 47 percent. The global bayesian analysis showed better values of the different statistical parameters for NRRF. Partial bayesian analysis indicated an important increment of sensitivity in patients with dilated pyelocalicial system: from 10 percent (RRF) to 74.6 percent (NRRF); and acute pyelonephritis: from 29.2 percent (RRF) to 66.2 percent (NRRF) while the sensitivity in patients with chronic nephropathy remained stable (70.1 percent). Conclusion NRRF calculation (cut-off 47 percent) provides useful and additional information to RRF, as it quantifies the relative quality of kidney tissue regardless of renal volume and better reflects better the scintigraphic findings.
Subject(s)
Humans , Male , Female , Infant, Newborn , Infant , Child, Preschool , Child , Kidney Function Tests/methods , Radiopharmaceuticals , Kidney , Data Interpretation, Statistical , ROC Curve , Retrospective Studies , Radiopharmaceuticals/pharmacokinetics , Kidney/physiopathology , Kidney/metabolism , Sensitivity and Specificity , Predictive Value of Tests , /pharmacokineticsABSTRACT
PURPOSE: Neonatal hydronephrosis has been detected with increasing frequency with the widespread use of prenatal ultrasonography, but the consensus about its postnatal management has not yet been reached, especially about surgical intervention. We attempted to determine the guideline of follow-up study and surgical intervention of hydronephrosis by analyzing clinical outcomes of neonates with hydronephrosis. MATERIALS AND METHODS: Between 1994 and 2000, 128 hydronephrotic kidneys were postnatally confirmed. Cases associated with other urologic anomalies were excluded and 90 unilateral hydronephrotic kidneys with a minimum follow-up of 12 months were enrolled in this study. We classified the patients into 6 groups according to the anterior posterior pelvic diameter(APPD) at initial ultrasonography(USG) within 1 month after birth. Renal USG and Tc99m-mercaptoacetyl triglycerine(MAG3) scan were done according to a set protocol, and pyeloplasty was performed when indicated according to our protocol. RESULTS: Most cases whose APPD were below 10 mm improved or resolved. Only few cases with APPD above 20 mm showed spontaneous improvement and most(88%) had undergone operation. Those with initial APPD within 10-19 mm showed variable outcomes. When the risk factors for irreversible renal functional deterioration were analyzed, the age at pyeloplasty and pre-operative functional deficit were significant. CONCLUSION: We concluded that in infants with initial APPD below 10 mm, consideration of surgery is not needed, and in those with initial APPD above 20 mm, early operation is recommended. Our set protocol based on initial USG is useful, but the cut-off value of relative renal function(RRF) for operation might be increased to 40% to improve post operative RRF.
Subject(s)
Humans , Infant , Infant, Newborn , Consensus , Follow-Up Studies , Hydronephrosis , Kidney , Parturition , Risk Factors , Ultrasonography , Ultrasonography, PrenatalABSTRACT
The previous reports have indicated that both the DMSA scan and the DTPA scan were significantly related with the relative renal function ( RRF) and there was a close relationship between the DMSA scan and the DTPA scan in the evaluation of the RRF We reviewed our experience with 24 cases, in which the DMSA scan and the DTPA scan were performed within 2 weeks from January 1987 to April 1991. The DMSA scan was more reliable than the DTPA scan and the difference of the RRF between right and left side by the DMSA scan was more apparent than that by the DTPA scan. However, in infants, both scans showed the reversed results. Our study suggests that DMSA scan is more reliable than the DTPA scan in the evaluation of the RRF, but both renal scans are inappropriate in infants, especially under the age of 1 months.