Nuclear Renography Research Articles

Management considerations for treating vesicoureteral reflux in children with solitary kidneys

Objectives. To evaluate the management approach for vesicoureteral reflux (reflux) into a solitary kidney. Methods. Outcomes of all children with solitary kidneys and reflux managed between 1981 and 1996 were reviewed. Solitary kidneys were documented by nuclear renography and ultrasonography; reflux was graded after cystography. Management consisted of observation and antimicrobial prophylaxis or surgery by ureteroneocystostomy or subureteric injection of polytetrafluoroethylene (STING). Follow-up ranged from 3 months to 14 years and included serial cystography, sonography, and serum creatinine measurement. Results. Twenty-one patients with a median follow-up of 26 months were identified. Etiologies included contralateral renal agenesis (14 children), multicystic dysplastic kidney (5 children), or nonfunctioning ureteropelvic junction obstruction (2 children). Low-grade (I to II) reflux was identified in 6 children, and high grade (III to V) was identified in 15. Reflux resolved in 20 patients. Five children with low-grade reflux were managed without surgery and demonstrated reflux resolution after a mean of 20.5 months. Renal function deteriorated in only 1 child. Ureteroneocystostomy was performed in 13 children with grades III to V reflux, and STING was performed in 1 child with grade II reflux. Every surgical patient maintained stable renal function and was infection-free during a mean follow-up of 56 months. Management by observation in 2 children with grades IV to V reflux resulted in spontaneous resolution in one and stable grade IV in the other. Conclusions. Reflux into the solitary functioning kidney may be managed by the same strategies used to manage unilateral reflux in children with two normally functioning kidneys: low-grade reflux by observation/chemoprophylaxis until spontaneous resolution occurs, and higher grades by surgery to protect renal function; however, chemoprophylaxis and serial imaging may be used until well-defined indications for surgery are satisfied. Renal function should be monitored diligently.

Uropathies malformatives de diagnostic anténatal: prise en charge néonatale et devenir de 100 enfants nés entre 1988 et 1990 au CHU d'Angers

Malformative uropathies diagnosed in utero are increasing in number. This work describes the decision strategy adopted in Angers concerning the neonatal handling of those abnormalities. Patients and methods. — One hundred children born between 1988 and 1990, with prenatally suspected fetal uropathy, were included in the study and followed for a period of 3 years. In every case, an ultrasound scan was performed at birth. In cases with persistent abnormality, a voiding cystourethrography was done in the first week of life. An intravenous urograph and/or a nuclear renography were performed during the second month of life. Results. — Twenty-nine children were normal. Seventy-one were affected by 126 isolated or related uropathies; the most frequent ones were the ureteropelvic junction obstruction syndrome (48), ureterovesical junction obstruction (18) and muticystic kidneys (13). A vesicoureteral reflux was associated in 22% of cases. The diagnosis was perfectly correlated with the prenatal diagnosis in 50% of cases. Fourteen of the normal children had a later ultrasound scan control, between 2 and 9 months; later on, three of them showed a moderate ureteropelvic junction obstruction syndrome. Amongst the 48 ureteropelvic junction obstruction syndromes, 22% have been operated on. The others obstructive uropathies remained stable or spontaneously improved. Discussion. — These results require us to discuss as matter of priority the large number of spontaneously regressive prenatal hydronephrosis and the necessity to establish a consensus for the pre and postnatal pathological thresholds of the anteroposterior pelvic diameter, the interest in carrying out a voiding cystography after the birth when dilatation is confirmed, the interest of nuclear renography for the diagnosis and follow-up of obstructive uropathies and the absence of urgency for surgery. Conclusion. — We propose a decision tree specifying the action to take when facing the diagnosis of a prenatal hydronephrosis. It could be a part of the reflection for the medical teams handling these uropathies in the aim of a consensual attitude which is now essential.

Is There a Best Alternative to Treating the Obstructed Upper Pole?

Purpose We addressed whether salvage of upper pole renal units in comparison to partial nephrectomy affects differential renal function in patients with a duplicated obstructed upper pole. Materials and Methods We retrospectively reviewed the records of all children who underwent surgery for a unilateral obstructed duplicated kidney at our institution from 1988 to 1995. Patients were evaluated with respect to postoperative complications, reoperation rate and percent change in differential renal function of the obstructed duplicated kidney, as determined by nuclear renography. Results We identified 46 patients with a unilateral obstructed upper pole of a duplicated kidney who were divided into 2 groups. Group 1 (12 patients) underwent an upper pole salvage procedure, that is ureteropyelostomy or ureteroureterostomy, and group (31 patients) underwent partial nephrectomy. Three reoperations (25 percent) were performed in group 1 and 1 (4 percent) was done in group 2. Postoperative symptomatic urinary tract infections were diagnosed in 3 group 1 patients (25 percent) and in 2 (8 percent) in group 2. Average change in ipsilateral renal function in the 8 patients who underwent upper pole salvage procedures was 2.25 plus/minus 2.34 percent (range -6 to 12). In the 8 patients who underwent upper pole nephrectomy and who also had postoperative renal scans average change in function was -1.25 plus/minus 4.51 percent (range -23 to +16). Conclusions There was no statistically significant loss of relative renal function in patients treated with partial nephrectomy and no significant gain in relative renal function in those treated with an upper pole salvage procedure. The reoperation rate was higher in the upper pole salvage than in the partial nephrectomy group (25 versus 4 percent). While not statistically significant, we believe that this rate is clinically important. We think that partial nephrectomy should remain the preferred treatment for most patients with obstructed duplicated kidneys.

Pressure Decay Half-life: A Method for Characterizing Upper Urinary Tract Urine Transport

Purpose We examined the pressure dynamics of hydronephrotic kidneys after elevated renal pelvic pressure developed. Materials and Methods A total of 40 patients (44 renal units) 0.2 to 12 years old was evaluated. Transiently elevated renal pelvic pressure was induced with a percutaneous nephrostomy infusion. After renal pelvic pressure increased the infusion was stopped and the subsequent decrease in pressure with time was plotted as a pressure decay curve. The rapidity of the decrease in renal pelvic pressure was then quantitated as a half-life for each pressure decay curve. Pressure decay half-lives were compared to corresponding pressure flow study results and diuretic nuclear renography half-lives. Results Renal units without elevated renal pelvic pressure during infusion at a high physiological flow rate were associated with relatively rapid pressure decay, whereas those with elevated renal pelvic pressure during infusion were associated with much slower pressure decay (p less than 0.0001). Diuretic nuclear renography half-lives had no correlation with collecting system pressure dynamics. Conclusions Pressure decay half-life provides an objective quantitative measure of the relative tendency for elevated renal pelvic pressure to persist. When used in conjunction with other diagnostic modalities, it may be a useful parameter for a comprehensive assessment of the risk of pressure induced injury in hydronephrotic kidneys.

The Effect of Newer Generation Lithotripsy Upon Renal Function Assessed by Nuclear Scintigraphy

Purpose We studied the effect of second generation lithotripsy on renal function. Materials and Methods We evaluated 42 patients with unilateral renal calculi by nuclear renography, serum creatinine levels, renal ultrasonography and plain radiographs. Results There was no significant change in glomerular filtration rate at 1 or 3 months. Split function of the treated kidneys was lower at 1 month (mean 47.2 percent, p = 0.01) and 3 months (47.3 percent, p = 0.01) than before treatment (49.1 percent). A greater than 5 percent decrease in split function of the treated kidney occurred at 1 month in 6 patients (16.2 percent) and at 3 months in 3. Of the patients 23 (62.2 percent) were stone-free and 11 had residual fragments less than 4 mm., with a 19 percent retreatment rate for an overall success rate of 91.9 percent. Conclusions Newer generation lithotriptors may limit renal damage while permitting satisfactory treatment of renal calculi.

Contradictory Supranormal Nuclear Renographic Differential Renal Function: Fact or Artifact?

We previously reported contradictory supranormal nuclear renographic differential renal function in cases of unilateral hydroureteronephrosis, in which the kidneys with hydroureteronephrosis paradoxically had a greater differential function than the contralateral normal mate, based on diethylenetriaminepentaacetic acid (DTPA) nuclear renography. To evaluate whether DTPA supranormal differential function represented true hyperfunction, patients with DTPA supranormal differential function were evaluated with dimercaptosuccinic acid (DMSA) nuclear renography and the results were compared. A total of 16 patients with unilateral hydronephrosis was identified to have DTPA differential function of 53 percent or more. They were younger than age 1 year and had never undergone any urological surgery. In all 16 patients the DMSA differential function (mean 51.1 percent, range 42 to 57 percent) was lower than their own corresponding DTPA differential function (mean 58.3 percent, range 53 to 66 percent, p less than 0.0001). In addition, the DMSA differential function was not significantly different from the intuitively anticipated mean of 50 percent (p = 0.48). The DTPA supranormal differential function identified in our patients was not corroborated by the DMSA differential function. With recent evidence that DMSA differential function may be a better predictor of outcome following relief of unilateral ureteral obstruction consideration should be given to using DMSA as a potentially more relevant method for differential function measurement in the setting of unilateral hydronephrosis. Conversely, until the potential deficiencies of DTPA are fully understood caution should be exercised in the interpretation of DTPA differential function in the setting of hydronephrosis.

Evaluation of Pediatric Hydronephrosis Using Individualized Pressure Flow Criteria

In pursuit of a diagnostic modality better able to assess collecting system urine transport characteristics while operating within physiological ranges, a new set of guidelines for the pressure flow study was proposed. An infusion rate individualized for each patient was chosen based on a calculated estimate of the maximum physiological urine output, adjusted for patient size and age. The upper limit of normal renal pelvic pressure used was 14 cm. water. We evaluated 37 renal units with grade 3 or 4 hydronephrosis with the individualized pressure flow study. Patient age ranged from 0.2 to 12 years (median 1.1). Calculated individualized infusion rates ranged from 1.3 to 12.5 ml. per minute and resulting renal pelvic pressures ranged from 7 to greater than 40 cm. water. In each patient the corresponding renal pelvic pressure resulting from a fixed 10 ml. per minute infusion rate was uniformly equal to or higher than the corresponding individualized study pressures (p < 0.0001). Disagreement between the individualized and fixed rate pressure flow studies was highest in the younger patients. The correlation coefficient between diuretic nuclear renography half-times and individualized pressure flow results was 0.09, indicative of a random association between the 2 variables. By using individualized infusion rates based on the calculated estimate of the maximum physiological urine output, much of the falsely high pressures induced by nonphysiologically high fixed infusion rates in pediatric patients can be avoided.

Evaluation of Pediatric Hydronephrosis Using Individualized Pressure Flow Criteria

In pursuit of a diagnostic modality better able to assess collecting system urine transport characteristics while operating within physiological ranges, a new set of guidelines for the pressure flow study was proposed. An infusion rate individualized for each patient was chosen based on a calculated estimate of the maximum physiological urine output, adjusted for patient size and age. The upper limit of normal renal pelvic pressure used was 14 cm. water. We evaluated 37 renal units with grade 3 or 4 hydronephrosis with the individualized pressure flow study. Patient age ranged from 0.2 to 12 years (median 1.1). Calculated individualized infusion rates ranged from 1.3 to 12.5 ml. per minute and resulting renal pelvic pressures ranged from 7 to greater than 40 cm. water. In each patient the corresponding renal pelvic pressure resulting from a fixed 10 ml. per minute infusion rate was uniformally equal to or higher than the corresponding individualized study pressures (p less than 0.0001). Disagreement between the individualized and fixed rate pressure flow studies was highest in the younger patients. The correlation coefficient between diuretic nuclear renography half-times and individualized pressure flow results was 0.09, indicative of a random association between the 2 variables. By using individualized infusion rates based on the calculated estimate of the maximum physiological urine output, much of the falsely high pressures induced by nonphysiologically high fixed infusion rates in pediatric patients can be avoided.

Contradictory Supranormal Differential Renal Function During Nuclear Renographic Investigation of Hydroureteronephrosis

We selected a group of children with unilateral hydroureteronephrosis to assess the significance of the differential renal function as determined by nuclear renography as a factor in defining obstructive dilatation. All children who presented to our institution during a 21-month period with unilateral hydroureteronephrosis and a normal contralateral kidney were reviewed. Patients with reflux or bladder pathology were excluded, resulting in 13 evaluable patients younger than age 2 years. Diuretic renography was performed using 99mtechnetium-diethylene- triaminepentaacetic acid in accordance with the well tempered renogram. Ancillary studies included voiding cystourethrography, ultrasonography and/or excretory urography.Of the 13 patients 5 had a differential function greater than 55% in the hydronephrotic kidney. Ten of the 13 patients, including the 5 with supranormal function, underwent surgical correction in the form of ureteral reimplantation for recurrent infections, increasing hydronephrosis, decreasing or decreased function and loss of parenchyma. Stenotic distal adynamic ureteral segments with proximal dilatation were confirmed in all cases.The implication by nuclear renography that a dilated kidney has better function than its morphologically normal counterpart is at variance with any available clinical or experimental data. The etiology of this apparently elevated function is unclear and its presence on a renographic study should not be interpreted as suggestive that the kidney is free of risk of nephron loss. Management decisions should not be based solely on the differential function as determined by nuclear renography.

Evolution in the management of infant pyeloplasty

Improving diagnostic modalities, evolving concepts regarding perinatal renal physiology, and advances in surgical technique have contributed to an evolution in the management of infant pyeloplasties. Currently, the majority of patients present with a prenatal diagnosis of ureteropelvic junction obstruction and do not require surgical intervention prior to 4 weeks of age. Postnatal ultrasound, voiding cystourethrography, and nuclear renography complete the diagnostic evaluation, with intravenous urography and retrograde pyelography being unnecessary in the majority of infants. A decreasing incidence of complications and a shortening of hospital stay has been documented. We presently prefer a dismembered, nonintubated technique performed through a dorsal lumbotomy approach.

Non-invasive renal artery duplex ultrasound and computerized nuclear renography to screen for and follow progress in renal artery stenosis

Non-invasive renal artery duplex ultrasound and computerized nuclear renography to screen for and follow progress in renal artery stenosis

Urine leaks after renal transplantation: value of percutaneous pyelography and drainage for diagnosis and treatment.

We reviewed our experience with 12 renal transplant patients who had urine leaks to compare the accuracies of sonography and nuclear renography with that of antegrade pyelography in establishing the diagnosis. The leak was proved by surgery in 11 of the 12 cases. We also determined the role of diverting percutaneous nephrostomy drainage in the treatment of such leaks. The diagnosis was established by sonography in eight (67%) of the 12 patients. Nuclear renography, performed in nine patients, showed decreased renal function but showed the leak in only three (33%) of the nine cases. Antegrade pyelography, performed in all 12 patients, showed leakage in 10 (83%). In the other two patients, follow-up nephrostograms done within 24 hr showed leaks near the ureterovesical anastomotic site. Seven of 11 patients who were managed with a combination of percutaneous nephrostomy drainage and surgical reconstruction were treated successfully (i.e., a functioning graft was retained); however, only one patient was managed successfully by percutaneous methods alone. Antegrade pyelography is more accurate than sonography and nuclear renography in the detection of urine leakage after renal transplantation. However, percutaneous nephrostomy drainage appears useful only as an adjunct to surgery for treatment of this complication.