Assessment of Pediatric Hydronephrosis Using Output Efficiency

Saunders, Catherine A.B.; Choong, Kevin K. L.; Larcos, George; Farlow, David; Gruenewald, Simon M.

doi:10.1097/00005392-199804000-00127

Cited by 10 publications

(12 citation statements)

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“…However, recently described variables, where calculations were based on the residual activity, might allow this kind of comparison [35]. The OE and PEE are analogous physiological, robust and well‐validated variables [30,32,36,37] which, based on the cardiac curve and the renal activity at a given moment of the acquisition, allows an evaluation of the amount which left the kidney and expressed as a percentage of what came in. The NORA is a simplification of those variables and is the renal activity at a given moment divided by the renal activity at 2 min [31].…”

Section: What If Frusemide Is Injected Early (F0 or F−15)?mentioning

confidence: 99%

Interpretation of the renogram: problems and pitfalls in hydronephrosis in children

et al. 2004

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The role of diuretic renography has become central in cases of upper tract dilatation, and in the first paper in this section the difficulties in interpreting results in asymptomatic congenital hydronephrosis are examined. These difficulties and controversies exist despite the presence of guidelines and consensus protocols, probably because renography procedures differ among centres. The authors found that there is a need for renography to be standardized for the optimum value to be obtained from the procedure. There are three papers from Los Angeles which attempt to standardize the measurement of bladder compliance, from both the theoretical and clinical perspective, and which assess the detrusor pressure rise of a normal bladder when filled to capacity. OBJECTIVE To discuss the main steps of renographic technique and underline some pitfalls related to the acquisition, processing and interpretation of diuretic renography, an important method for guiding the management of asymptomatic congenital hydronephrosis. METHODS Despite guidelines and consensus protocols, renographic procedures differ among centres, causing difficulties in comparison and controversy in the interpretation of results. Thus we comprehensively assessed published papers on the subject of diuretic renography. RESULTS Differential renal function (DRF) is a robust measure provided there is adequate background subtraction. Pitfalls are related to the drawing of regions of interest, particularly in infants, to estimating the interval during which DRF is calculated, and to an adequate signal‐to‐noise ratio. There is no definition of a ‘significant’ reduction in DRF. The classical variables of the diuretic renogram may not allow an estimate of the best drainage. Poor pelvic emptying may be apparent because the bladder is full and because the effect of gravity on drainage is incomplete. Estimating the drainage as residual activity rather than any parameter on the slope might be more adequate, especially if the time of frusemide administration is changed. Renal function and pelvic volume can influence the quality of drainage. Drainage may be better estimated using new tools. CONCLUSION Provided the investigation is standardized and potential pitfalls accounted for, the diuretic renogram provides valuable and reproducible quantitative information on DRF and drainage.

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Section: What If Frusemide Is Injected Early (F0 or F−15)?mentioning

confidence: 99%

Interpretation of the renogram: problems and pitfalls in hydronephrosis in children

et al. 2004

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“…Although this has not been formally studied in transplantation, there is no reason to believe that renography will be more accurate in the investigation of obstruction. Output efficiency has the advantage in that it is relatively independent of variations in renal isotopic uptake rate and therefore allows more accurate assessment of outflow obstruction in native kidneys (2,3). In both the adult and paediatric populations, it provides better diagnostic yields than standard diuretic renography (2,3).…”

Section: Discussionmentioning

confidence: 99%

“…Output efficiency has the advantage in that it is relatively independent of variations in renal isotopic uptake rate and therefore allows more accurate assessment of outflow obstruction in native kidneys (2,3). In both the adult and paediatric populations, it provides better diagnostic yields than standard diuretic renography (2,3). Our study has demonstrated that OE further improved the diagnostic yield compared with other parameters in patients with kidney transplantation without sacrificing sensitivity.…”

Section: Discussionmentioning

confidence: 99%

“…MAG3 is an analogue of ortho-iodohippuran, which is excreted primarily by tubular secretion despite poor renal function (1). Its improved renal handling has facilitated investigation of renal disorders such as KTO by diuretic renography (1)(2)(3)(4)(5)(6). By correction of the renogram curve for kidney transplant uptake, output efficiency (OE) can be calculated for the kidney transplant, which has a number of advantages over conventional parameters.…”

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confidence: 99%

“…By correction of the renogram curve for kidney transplant uptake, output efficiency (OE) can be calculated for the kidney transplant, which has a number of advantages over conventional parameters. Measurement of OE during Tc 99m MAG3 diuretic renography has proven superior sensitivity in the diagnosis of suspected obstruction in native kidneys of children (2) and adults (3), and may potentially improve the diagnostic yield in transplant urinary obstruction (4). However, there are little or no data for OE and other functional parameters to assess their functional utility in the diagnosis of KTO.…”

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Diagnosis of kidney transplant obstruction using Mag3 diuretic renography

Nankivell¹,

Cohn

Spicer³

et al. 2001

Clinical Transplantation

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Kidney transplant obstruction (KTO) following renal transplantation remains an important reversible cause of allograft dysfunction, requiring prompt diagnosis to prevent long-term graft damage. Although ultrasound can accurately diagnose renal transplant hydronephrosis, it cannot be used to assess its functional significance. We prospectively assessed the utility of technetium-99m mercaptoacetyltriglycine (Tc99m MAG3) diuretic renography for the diagnosis of allograft KTO, using standard visual and quantitative parameters, as well as calculated renal output efficiency (OE), which has been postulated to improve diagnostic yield. From a cohort of 45 renal transplant patients, two subgroups were formed. The first group of transplant recipients (n = 21) with stable function and no obstruction was used to derive normal values for Tc99m MAG3 scans. A second group of transplant recipients with acute renal dysfunction in whom KTO was clinically suspected was used to test the diagnostic utility of these derived values (n = 43 scans). KTO was diagnosed independently of the MAG3 scans by a fall in the serum creatinine in response to renal pelvis urinary drainage. OE in 12 renal allografts with KTO was significantly reduced compared with 31 Tc99m MAG3 scans without KTO (59.6 +/- 18.9 vs. 81.6 +/- 5.4%, p < 0.001). In KTO, the mean time of isotope appearance in the bladder (time to bladder [TTB]) was extended compared with unobstructed allografts (7.9 +/- 4.1 vs. 3.6 +/- 1.5 min, p < 0.001). Measurement of OE significantly improved the accuracy of diuretic MAG3 renography in the diagnosis of renal allograft KTO, especially when supplemented by the TTB, parenchymal transit time and shape of the renogram curve. Ureteric obstruction of the kidney transplant can be diagnosed with an OE reduced to < 75% (sensitivity 92%, specificity 87%) and confirmed by isotope hold-up in the pelvicalyceal system. A normal or slowly declining renogram curve effectively excluded KTO (sensitivity of 96%, negative predictive value of 84%). A parenchymal transit time of > 5 min and a TTB of > 7 min both yielded a sensitvity of 92% and a specificity of 81%. In conclusion, MAG3 renography is a clinically useful investigation for the diagnosis of KTO.

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Causes of hydronephrosis in pyelonephritic children

Sorkhi

2005

Indian J Pediatr

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Assessment of Pediatric Hydronephrosis Using Output Efficiency

Cited by 10 publications

References 0 publications

Interpretation of the renogram: problems and pitfalls in hydronephrosis in children

Interpretation of the renogram: problems and pitfalls in hydronephrosis in children

Diagnosis of kidney transplant obstruction using Mag3 diuretic renography

Causes of hydronephrosis in pyelonephritic children

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