Surgical correction of vesicoureteral reflux: 5-year follow-up with 99Tcm-DMSA scintigraphy

AIM: To evaluate kidney function before and after surgical correction of vesicoureteral reflux. The long-term effect was measured with quantitative nephro-scintigraphy using 99Tcm labelled dimercaptosuccinic acid (99Tcm-DMSA). METHODS: Forty-five children with a history of urinary tract infections due to vesicoureteral reflux (VUR) were studied. VUR grade was determined with contrast voiding cystourethrography. Planar scintigraphy was performed with 99Tcm-DMSA and uptake measured as a percentage of injected dose. Kidney function was evaluated at baseline and 5 years after corrective surgery. RESULTS: Three months after surgery, persistent mild reflux was found in eight of 76 treated renal units. Kidney uptake at 5-year follow-up was unchanged in the majority of children, indicating preservation of renal function found at baseline. The split renal function showed an excellent correlation (r = 0.99) between baseline and follow-up studies (regression slope 1.01). Percentage uptake had a regression slope of 0.89 significantly different from unity (P<0.05). Empirical kidney-depth correction techniques were compared. The scintigraphic pattern worsened in six kidneys, indicative of increased scarring in a minority of children. CONCLUSION: Planar nephro-scintigraphy with 99Tcm-DMSA was well tolerated in our paediatric population, and appeared appropriate to evaluate kidney function in time. After surgical correction of VUR, the baseline function was maintained in 94% of kidneys.     

Imaging in ureteral complications of renal transplantation: value of static fluid MR urography

Ureteral obstruction is an infrequent complication after renal transplantation that may cause rapid loss of transplant function. We tested static fluid MR urography for determining the cause of graft hydronephrosis. Magnetic resonance urography was performed in nine transplants with dilated collecting systems on ultrasound. A heavily T2-weighted 3D turbo spin-echo sequence on a 1.5-T scanner was used and maximum intensity projections were obtained. The patients also underwent excretory urography (n = 1), renal scintigraphy (n = 1), antegrade pyelography (n = 3), voiding cystourethrography (n = 4), and non-enhanced CT (n = 2). Six patients had pathologic conditions including ureteral stricture, compression by lymphoceles, implantation stenosis, vesicoureteral reflux, and late-occurring transitional cell carcinoma at the implantation site. Static MRU was able to diagnose or exclude a dilation of the graft collecting system. It visualized the course of the ureters and localized the obstruction site in four of five obstructed transplants. In one case the ureter was obscured by lymphoceles, which were demonstrated by hydrographic MRU as well. The definite cause for obstruction was provided in only 2 of 5 cases. Dilation due to vesicoureteral reflux could not be differentiated. The current multimodality approach to renal transplant imaging already provides comprehensive assessment of graft hydronephrosis. Static MRU may be useful in some cases since complications associated with intravenous iodinated contrast or antegrade pyelography can be avoided. Its main drawback, the lack of functional information, may be overcome by combining it with contrast-enhanced MRU. Received: 18 February 1999; Revised: 23 July 1999; Accepted: 18 November 1999     

Reflux in native kidneys mimicking urine leak postrenal transplant

A 19-year man underwent live related renal transplantation for end-stage renal disease. He was referred for a baseline renal scan on day 4. The urine output was satisfactory and the serum creatinine showed a decreasing trend. Renal dynamic scintigraphy with technetium-99m ethylenedicysteine demonstrated radiotracer activity above the transplant kidney, suspected to be a urine leak. Postvoiding posterior, delayed images confirmed that the radiotracer activity in the anterior postvoiding images was the result of vesicoureteral reflux from the patient's native kidneys.     

(99m)Tc-DMSA scintigraphy diagnosing crossed renal ectopia with fusion in a three years old boy

A 3 years old boy with a history of surgery for orchidopexy was admitted to our hospital with fever and abdominal pain. Clinical examination and laboratory investigations revealed urinary tract infection with renal involvement. Ultrasonography demonstrated a solitary left kidney and raised the suspicion of a fusion anomaly. Voiding cystography disclosed grade III vesicoureteral reflux and technetium-99m dimercaptosuccinic acid scintigraphy revealed right to left crossed renal ectopia with fusion (L-shaped kidney). The patient is undergoing standard follow-up for the early detection of possible renal complications. In conclusion, L-shaped kidney is a rare entity and the (99m)Tc-DMSA scintigraphy played an important role on timely diagnosis.     

Value of supranormal function and renogram patterns on 99mTc-mercaptoacetyltriglycine scintigraphy in relation to the extent of hydronephrosis for predicting ureteropelvic junction obstruction in the newborn.

We investigated the value of supranormal function and renogram patterns on (99m)Tc-mercaptoacetyltriglycine ((99m)Tc-MAG3) scintigraphy in relation to the extent of hydronephrosis for predicting ureteropelvic junction (UPJ) obstruction in the newborn. METHODS: We studied 48 patients with prenatally diagnosed unilateral hydronephrosis that was confirmed on postnatal ultrasonography. The anteroposterior pelvic diameter (APPD) and the Society for Fetal Urology (SFU) grade were measured on 1-mo ultrasonography to assess the extent of hydronephrosis. Neonates with an APPD of or=55%) and renogram grades (1, not obstructive; 2, indeterminate; 3, obstructive; and 4, prolonged parenchymal transit) were determined on 1-mo (99m)Tc-MAG3 renography. Multivariate logistic regression analysis was performed to predict the presence of obstruction. RESULTS: Of the 48 kidneys with hydronephrosis, 19 were diagnosed as having UPJ obstruction. Twenty-nine kidneys were classified as having nonobstructive hydronephrosis. The APPD of the 19 kidneys with obstruction (24.3 +/- 9.2 mm) was significantly larger than that of the 29 kidneys without obstruction (17.5 +/- 11.2 mm; P < 0.05). The SFU grades of UPJ obstruction (2 with grade 3, 17 with grade 4) were also significantly higher than those without UPJ obstruction (grades 1-4 in 1, 6, 10, and 12 kidneys, respectively; P < 0.01). Supranormal function was present in 4 kidneys with UPJ obstruction but in none without obstruction (P < 0.001). (99m)Tc-MAG3 renography of the 19 obstructions showed grades 2, 3, and 4 renograms in 4, 8, and 7 patients, respectively. The 29 without obstruction revealed significantly lower grades (grades 1-4 in 10, 13, 5, and 1 patient, respectively; P < 0.001). Multivariate logistic regression analysis revealed that the addition of supranormal function or renogram grade in the model significantly increased the likelihood ratio in comparison with that of the SFU grade only (chi(2) = 7.73 and 9.99, respectively; P < 0.01). Of the 29 neonates with SFU grade 4, supranormal function or renogram >or= grade 4 had a positive predictive value of 90% (9/10). CONCLUSION: (99m)Tc-MAG3 renography at 1 mo after birth has a significant additive value in relation to the degree of hydronephrosis in predicting UPJ obstruction in patients with prenatally diagnosed unilateral hydronephrosis with normal function.     

Normal differential renal function does not indicate a normal kidney after partial ureteropelvic obstruction and subsequent relief in 2-week-old piglets

Purpose  We investigated the functional consequences of relieving ureteric obstruction in young pigs with experimental hydronephrosis (HN) induced by partial unilateral ureteropelvic obstruction. Materials and methods  Three groups of animals were followed from the age of 2 weeks to the age of 14 weeks: Eight animals had severe or grades 3–4 HN throughout the study. Six animals had relief of the obstruction after 4 weeks. Six animals received sham operations at both ages. Morphological and functional examinations were performed at age 6 weeks and again at age 14 weeks and consisted of magnetic resonance imaging (MRI), technetium-diethylenetriaminepentaaceticacid (^99mTc-DTPA) renography, renal technetium-dimercaptosuccinicacid (^99mTc-DMSA) scintigraphy, and glomerular filtration rate (GFR) measurement. Results  After relief of the partial obstruction, there was reduction of the pelvic diameter and improvement of urinary drainage. Global and relative kidney function was not significantly affected by either obstruction or its relief. Renal ^99mTc-DMSA scintigraphy showed a change in both the appearance of the kidney and a change in the distribution within kidneys even after relief of obstruction. Conclusion  This study shows that partial ureteric obstruction in young pigs may be associated with little effect on global and differential kidney function. However, even after relief of HN, the distribution of ^99mTc-DMSA in the kidney remains abnormal suggesting that a normal differential renal function may not represent a normal kidney.     

Ectopic ureteroceles in infants with prenatal hydronephrosis: use of renal cortical scintigraphy

PURPOSE: This study assesses the contribution of renal cortical scintigraphy in the diagnostic evaluation of infants with ectopic ureteroceles. METHODS: The records of 20 infants (age range, 3 weeks to 4 months) who were referred for renal cortical scintigraphy after an ectopic ureterocele associated with a duplex kidney was found during follow-up of prenatal hydronephrosis were reviewed retrospectively. All infants underwent voiding cystourethrography, ultrasonography, and Tc-99m DMSA scintigraphy. RESULTS: All upper moieties showed absent or depressed Tc-99m DMSA uptake. Upper moiety functional impairment was associated with structural abnormalities shown by ultrasonography. The degree of functional impairment was reflective of ultrasonographically defined cortical thickness relative to pelvic diameter, but this relation varied. Eight of 20 (40%) lower moieties had diffusely depressed relative Tc-99m DMSA uptake. Focal defects were also present in three of these eight (38%) lower moieties. Lower moiety functional impairment was associated with higher degrees of pelvic dilatation and with vesicoureteral reflux. Ultrasonography revealed diffuse parenchymal thinning in four of the eight (50%) lower moieties with depressed uptake. Ultrasonography did not define focal parenchymal loss in any lower moiety. CONCLUSIONS: The degree to which function is impaired in the upper moieties of duplex kidneys with ureters terminating in ectopic ureteroceles is not highly predictable by ultrasonography. Lower moiety functional impairment and cortical defects are frequently present in these kidneys and often occur without ultrasonographic evidence of parenchymal damage. Use of renal cortical scintigraphy in the diagnostic evaluation of infants with ectopic ureteroceles is supported.     

Gamma camera renography with 99Tcm-MDP and 131I-Hippuran

Nineteen patients with urologic disorders referred to bone scintigraphy were evaluated with a dual radioisotope technique using simultaneous injection of 99Tcm-MDP and 131I-Hippuran. The MDP and Hippuran renograms showed in general the same pattern and there was no difference between the kidney function determined with the two radionuclides. The peak of the MDP curves occurred later and was less distinct than that of the Hippuran curves. The residual activity of the kidneys 20 min after the injection was higher on the MDP renograms compared with the Hippuran renograms. The early sequential MDP images were superior in quality to the Hippuran images and to the renal images obtained at bone scintigraphy. The early MDP images correlated well with the findings at urography performed in 12 patients, as all cases of radiologically diagnosed hydronephrosis, reduction of renal parenchyma and renal mass lesions became demonstrated. Renal calculi were only diagnosed at urography. In conclusion, MDP cannot replace Hippuran as a renal radionuclide agent, mainly due to its lower extraction ratio and the high bone uptake. However, an increased use of early dynamic renal imaging is recommended in urologic patients referred to bone scintigraphy as valuable information about renal function may be obtained by this procedure.     

Technetium-99m-dimercaptosuccinic acid renal scintigraphy in children with urinary tract infections

The aim of this study was to determine the incidence of abnormal dimercaptosuccinic acid-Tc-99m ((99m)Tc-DMSA) renal scintigraphy findings in children with culture proved urinary tract infection (UTI) with or without vesicoureteral reflux (VUR). (99m)Tc-DMSA renal scintigraphy was performed in 343 children with culture documented UTI (247 girls and 96 boys) aged from three months to 14 years (middle age of 4.82 years). The children studied were all those submitted for renal scintiscan to the Institute of Nuclear Medicine, Military Medical Academy, Belgrade during a five-year period (2000-2004). Micturating cystoureterography (MCU) performed in all patients before (99m)Tc-DMSA scan, revealed VUR in 213 children, while in 130 children VUR was not detected by MCU. In 15 of the 213 children the grade of VUR was I, in 88 was II, in 57 was III, in 33 was IV and 20 children had grade V of VUR. Findings of (99m)Tc-DMSA renal scintigraphy were classified as: normal, equivocal and abnormal. Statistical analysis was performed using c(2)test. In all patients abnormal findings were detected in 38% (131/343), normal in 51% (174/343) and equivocal findings in 11% (38/343). In children with UTI and VUR the incidence of abnormal findings was 53% (112/213), of normal 37% (80/213) and of equivocal findings 10% (21/213). In children with UTI without VUR the incidence of abnormal findings was 15% (19/130), of normal findings 72% (94/130), and of equivocal findings 13% (17/130). The incidence of abnormal findings was significantly higher in children with UTI and VUR than in those with UTI without VUR (P<0.001). In children with VUR grades I, II, III, IV and V abnormal findings were 33%, 32%, 60%, 79% and 95% respectively. The incidence of abnormal findings was higher in children with VUR grades IV and V, than in grade I and II (P<0.001). Our results suggest that (99m)Tc-DMSA renal scintigraphy in children can discriminate between grade I-II and IV-V of VUR and also that in children with UTI and VUR abnormal findings in the scintiscan were more than three times higher than in children with UTI alone.     

"Indirect" radioisotope cystography after the furosemide test: its diagnostic efficacy compared to "direct" study

The diagnostic efficacy was investigated of "indirect" radionuclide cystography after a furosemide test in the detection of vesicoureteral reflux. A single i.v. injection of 99mTc-diethylenetriaminepentacetic acid (DTPA) was administered during sequential renal scintigraphy. "Direct" radionuclide cystography with 99mTc-DTPA was assumed as the "golden standard". Thirty-three patients, 24 of whom in pediatric age, were examined with "indirect" radionuclide cystography after a furosemide test: the method had 32% sensitivity according to restrictive positivity criteria versus 59% according to less restrictive ones. In conclusion, "indirect" radionuclide cystography, in spite of the advantages coming from the use of the diuretic, cannot be considered as an efficient technique to recognize vesicoureteral reflux, especially when the latter is present at a low degree.     

Effect of chronic, low-pressure, sterile vesicoureteral reflux on renal growth and function in a porcine model: a radiologic and pathologic study

PURPOSE: To study the effects of chronic, low-pressure, sterile vesicoureteral reflux (VUR) on renal growth and function in a porcine model. MATERIALS AND METHODS: Unilateral VUR was created in five pigs, with the contralateral kidney serving as a control. Preoperatively, and 1 year later, ultrasonography, technetium 99m-dimercaptosuccinic acid (DMSA) scintigraphy, contrast material-enhanced computed tomography (CT), and contrast-enhanced magnetic resonance (MR) imaging were performed. Morphologic abnormalities and relative uptake of (99m)Tc-DMSA were recorded. The postcontrast enhancement ratios for parenchymal regions of interest at CT and MR imaging were determined. Ruthenium 103-labeled microspheres were used to determine regional blood flow. After the pigs were sacrificed, the kidneys were excised, weighed, and analyzed pathologically. RESULTS: Two of five refluxing kidneys had less than 45% function at scintigraphy. One of these two kidneys was small at postmortem examination. There were no other imaging or gross pathologic abnormalities. There was no significant difference in regional blood flow between the refluxing and nonrefluxing kidneys. In all of the operated on kidneys, histologic examination showed focal chronic inflammation and fibrosis. CONCLUSION: Low-pressure sterile reflux into previously normal kidneys led to mild, focal, chronic interstitial inflammation and fibrosis after 1 year. Imaging findings were normal apart from a subtle decrease in tubular function in two refluxing kidneys.     

F+0 diuresis renography in infants and children.

The purpose of this study was to evaluate the feasibility of modifying diuresis renography by the simultaneous administration of 99mTc-mercaptoacetyltriglycine (MAG3) and furosemide in the investigation of hydronephrosis and hydroureteronephrosis in infants and children. Two parameters were assessed: the diuretic response in normal kidneys and the ability of the F+0 study to differentiate between renal obstruction and nonobstruction and to identify the level of obstruction in cases of renal obstruction. METHODS: Seventy-two patients (48 males, 24 females; age 2 d to 7 y; median age 6 wk) with sonographic diagnoses of hydronephrosis or hydroureteronephrosis were reviewed prospectively over a 3-y period. All patients had prior sonographic studies and micturating cystourethrography. Bladder catheterization was not routinely performed and was undertaken only if the child had suspected vesicoureteric junction (VUJ) obstruction or grade II or more vesicoureteric reflux. A weight-adjusted dose of 99mTc-MAG3 (maximum 200 MBq, minimum 20 MBq) and 1 mg/kg of furosemide (maximum 40 mg) were administered intravenously at the same time. Posterior imaging of the kidneys and bladder was performed for 20 min and followed by gravity-assisted drainage or imaging after voiding. All patients were followed-up for 6-12 mo, and the final diagnoses were based on either surgery or conservative management with repeated sonography or follow-up 99mTc-MAG3 studies (or both). The results of the F+0 diuresis renography were then compared with the final diagnoses. RESULTS: A renal unit was defined as a kidney and its ureter. There were 151 renal units with 1 patient having bilateral duplex kidneys, 6 patients having unilateral duplex kidneys and 1 patient having a solitary kidney. Fifty-five normal renal units and 96 abnormal renal units on the basis of sonographic findings were assessed. The furosemide clearance half-time for the 55 normal renal units was 1.3-6.3 min (mean 3.8 min). Of the 96 abnormal renal units, 53 were classified as nonobstructed and 43 were classified as obstructed. Of the 53 renal units classified as nonobstructed, there were 48 true-negative studies and 5 false-negative studies; of the 43 renal units classified as obstructed, there were 40 true-positive studies and 3 false-positive studies. The sensitivity was 88.9%, specificity was 94.1% and accuracy was 91.7%. The level of obstruction, either pelviureteric junction or VUJ, was also correctly identified. CONCLUSION: F+0 diuresis renography shows excellent diuretic responses in normal kidneys and is a valid method for the investigation of hydronephrosis and hydroureteronephrosis in infants and children.     

Evaluation of 99mTc-MAG3 (mercaptoacetyltriglycine) renography for pediatric patients

It is difficult to evaluate renal function with 99mTc-MAG3 renography in both adult and pediatric patients. We examined 109 pediatric patients with various renal diseases using 99mTc-MAG3 renography. Tenal diseases were classified as follows: 9 vesicoureteral reflux, 4 ureteropelvic junctional stenosis, 3 double pelvis, 23 hydronephrosis, 4 glomerulonephritis, 4 nephrotic syndrome, 24 hemolytic uremic syndrome, 10 others; and 24 patients without abnormal findings on other examinations. After hydration and sedation, 100-200 MBq of 99mTe-MAG3 was injected intravenously. All patients were placed in the supine position, and dynamic data acquisition at 12 sec/frame x 100 frames was performed from the back. The renograms were prepared with the ROIs (regions of interest) set to include the entire kidney. Tmax and T1/2 of renograms were measured for 26 kidneys with no abnormal findings. The correlations between Tmax or T1/2 and age (days after birth) were determined by a linear or logarithmic function. The logarithmic function (Y = 7.49 - 0.56 logeX, r2 = 0.134) yielded a higher correlation than did the linear function (Y = 5.16 - 0.00194X, r2 = 0.089) between Tmax and age. For T1/2 and age (days after birth), the linear function (Y = 8.07 - 0.00451X, r2 = 0.222) yielded a higher correlation than the logarithmic function (Y = 11.9 - 0.986 logeX, r2 = 0.192). Our findings suggest that prolonged Tmax is normalized more rapidly than T1/2 after birth in infants. A delayed excretion phase is not suggestive of renal dysfunction, but is characteristic of renograms in pediatric patients. Abnormality was detected in all patients with hydronephrosis using 99mTc-MAG3 renography. On the other hand, a quantitative study was required because renography detected no abnormality for some of patients with disorders of renal parenchyma.     

Clinical impact of differential renal function to indicate and assess pyeloplasty and the significance of coexisting vesicoureteral reflux

PURPOSE: In patients with ureteropelvic junction obstruction (JPJO) who are conservatively treated, 5% to 10% of them show a deterioration of renal function without recovery after delayed pyeloplasty. Should surgery be indicated based on observed deterioration of differential renal function (DRF)? Can we expect improvement of the DRF after pyeloplasty? What other influencing parameters may affect DRF? MATERIALS AND METHODS: In this study, the authors examined 85 ureterorenal junctions that had undergone the Anderson-Hynes technique for surgical correction of UPJO. Based on the values obtained from the preoperative DRF (Tc-99m mercaptoacetyltriglycine), the cases were separated into three categories: group I had poor DRF (less than 11% of total renal function [TRF]), group II had moderate DRF (11% to 33% of TRF), and group III had adequate DRF (more than 33% of TRF). Twelve months after surgery, renal function was reassessed. The results were correlated with age at surgery, symptoms, coexisting vesicoureteral reflux, and drainage. RESULTS: Seven ureterorenal junctions (8%) comprised group I, 15 (18%) comprised group II, and 63 (74%) comprised group III. After UPJO repair, 13% showed marked improvement in DRF, 86% remained stable, and 1% exhibited diminished function. In 50% of the renal cases with preoperative DRF less than 33%, postoperative improvement was seen. In follow-up renal scans, 30 cases (35%) revealed nonobstructive drainage, whereas the remaining 53 junctions (62%) showed moderate delayed drainage. Both the moderate delayed group (57%) and the nonobstructive group (50%) showed similar DRF improvement. Sixty-six percent of the patients with impaired DRF improved after pyeloplasty performed within the first 3 months of life, compared with 42.8% of patients in whom surgery was performed after 5 years of age. Vesicoureteral reflux was evident in 27.2% of the patients with preoperative impaired DRF compared with 11% with normal DRF. Forty-five percent of the patients with impaired DRF and no improvement after surgery had coexisting vesicoureteral reflux, compared with 9% of those with postoperative improvement. CONCLUSIONS: Sustained renal impairment after pyeloplasty is likely as a result of preexisting renal dysplasia with vesicoureteral reflux. Moderate delayed drainage after surgery does not affect DRF. Surgery for UPJO should be indicated independent of a DRF follow-up (except very low DRF) or the age at the time of diagnosis.     

Single photon emission computed tomography with Tc-99m-dimercaptosuccinic acid in patients with upper urinary tract infection and/or vesicoureteral reflux

By means of Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy, an established method for assessing renal cortical damage, we evaluated the pick-up rate for renal defects (scars) by single photon computed tomography (SPECT) and planar images of 10 normal volunteers, and 58 patients (70 scintigrams) with upper urinary tract infections, most of whom had a history of vesicoureteral reflux (VUR). The positive study rate for renal defects depended on the severity of VUR. The overall positive rates for renal cortical defects obtained by DMSA SPECT imaging and DMSA planar imaging were 60% and 43%, respectively, and the difference between these was significant (p less than 0.005). The mean absolute individual renal uptake (/injected dose) at 2 hours post-injection was decreased in kidneys with defects detected by SPECT alone. The positive study rate for intravenous urography (IVU) depended on the grade of VUR and was 15% overall. DMSA SPECT imaging detects renal cortical defects at greater frequency than previously achieved.     

Urinary tract infection and other pediatric considerations.

Urinary tract infection in childhood can lead to chronic sequelae, particularly in the presence of vesico-ureteric reflux or obstruction. The renal complications of acute pyelonephritis or residual chronic renal cortical scarring are most accurately evaluated with scintigraphy using (99m)Tc dimercaptosuccinic acid. The diagnosis of renal obstruction can be problematic, particularly in infants and children. Diuresis renography is an established tool in diagnosing and assessing the severity of obstruction. However the methodology for performing diuresis renography is a very controversial area in paediatric nuclear medicine, due to the lack of a gold standard. The surgical management of neonatal hydronephrosis is similarly controversial.     

Retrograde echocystography: a new ultrasonographic technique for the diagnosis and staging of vesicoureteral reflux]

PURPOSE: We investigated the accuracy of a new US investigation technique, called retrograde cystography US, in the early diagnosis and staging of vesicoureteral reflux. MATERIAL AND METHODS: We examined 5 patients, aged 3 months to 10 years, suffering from hydronephrosis and/or pyelonephritis. Retrograde cystography US was followed by conventional retrograde cystography. Retrograde cystography US consists in the transcatheter introduction of a contrast agent (Levovist, Schering AG, Berlin, Germany) into the bladder and a subsequent color Doppler examination to show or exclude the presence of reflux. Superpubic scanning of bladder, ureters and pyelocaliceal cavity was performed after echocontrast agent introduction to assess the reflux grade. US was performed with an Esaote AU 590 asynchronous scanner (Esaote Biomedica, Genova, Italy) with a 3.5 MHz convex probe. RESULTS: After the transcatheter introduction of Levovist, vesicoureteral reflux was seen in 5/5 patients. Reflux grade was also measured with US and then confirmed at retrograde cystography. In a patient with pyelonephritis and no reflux at follow-up cystography, retrograde cystography US identified a unilateral reflux (grade 1). DISCUSSION AND CONCLUSIONS: Retrograde cystography US showed the echocontrast agent in the urinary tract and assessed the reflux grade in all 5 patients, which was then confirmed at cystography. In a patient with grade 1 unilateral reflux at cystography US, follow-up conventional cystography showed no reflux, which seems to confirm a higher sensitivity of the US technique. The total agreement of conventional and US findings seems to confirm the importance of the US method for the diagnosis and staging of vesicoureteral reflux.     

Antenatal hydronephrosis: negative predictive value of normal postnatal ultrasound--a 5-year study

AIM: To determine whether normal postnatal ultrasound, as part of a strict screening protocol for the detection and follow-up of antenatal hydronephrosis, effectively excludes the majority of babies with congenital urinary tract abnormalities that would otherwise present with a urinary tract infection. MATERIALS AND METHODS: We retrospectively reviewed all babies who had postnatal follow-up of antenatally detected hydronephrosis over a 5-year period at our institution, a district general Trust with a specialist paediatric unit. We then studied all babies presenting with urinary tract infection before their first birthday to our institution over the same period. By cross-referencing these two study groups we were able to determine which babies developed a urinary tract infection having been previously discharged after normal postnatal ultrasound. RESULTS: Four hundred and twenty-five babies had postnatal follow-up of antenatal hydronephrosis. Of these, 284 were investigated with ultrasound alone. In the same 5-year period, 230 babies presented with urinary tract infection before their first birthday. Only three of these babies had been previously discharged after normal postnatal ultrasound. The negative predictive value of a normal postnatal ultrasound was therefore 98.9% (281/284) for babies who subsequently presented with a urinary tract infection before their first birthday. CONCLUSION: Careful antenatal and postnatal ultrasound with strict protocols is effective in detecting congenital renal tract abnormalities. Infants discharged after normal postnatal ultrasound are highly unlikely to still have an undetected urinary tract abnormality. We suggest that all babies with antenatal hydronephrosis are started on prophylactic antibiotics at birth, pending further investigation. All babies without features of severe obstruction antenatally should have their postnatal ultrasound delayed for a month. We recommend selective use of micturating cystourethrogram (MCUG), and delaying this investigation until the baby is 3 to 4 months old to allow for spontaneous resolution of vesicoureteric reflux. We do not believe that all babies with antenatal hydronephrosis require MCUG, providing a clear protocol is followed.     

What's new in pediatric uroradiology

The diagnosis and treatment of infants and children with urinary tract abnormalities have recently been affected by three developments. First, hydronephrosis can be detected in the fetus on obstetrical ultrasonography. Prenatal detection has resulted in a marked increase in the number of neonates referred for uroradiologic evaluation. Ureteropelvic junction (UPJ) obstruction, ureterovesical junction obstruction (UVJ), and reflux have been found to be the most common causes of hydronephrosis. Prophylactic antibiotics begun soon after delivery can prevent infection and its sequelae. Second, multicystic dysplastic kidney can now be accurately diagnosed preoperatively by a combination of ultrasonography and renal scintigraphy. This diagnostic certainty makes the decision to remove such a kidney a philosophical one. Third, it has been learned that reflux is sometimes familial. Nuclear cystography is an accurate and efficient method for screening asymptomatic family members.     

What’s new in pediatric uroradiology

The diagnosis and treatment of infants and children with urinary tract abnormalities have recently been affected by three developments. First, hydronephrosis can be detected in the fetus on obstetrical ultrasonography. Prenatal detection has resulted in a marked increase in the number of neonates referred for uroradiologic evaluation. Ureteropelvic junction (UPJ) obstruction, ureterovesical junction obstruction (UVJ), and reflux have been found to be the most common causes of hydronephrosis. Prophylactic antibiotics begun soon after delivery can prevent infection and its sequelae. Second, multicystic dysplastic kidney can now be accurately diagnosed preoperatively by a combination of ultrasonography and renal scintigraphy. This diagnostic certainty makes the decision to remove such a kidney a philosophical one. Third, it has been learned that reflux is sometimes familial. Nuclear cystography is an accurate and efficient method for screening asymptomatic family members.