Acid Renal Scan Research Articles

Identifying Children with Vesicoureteral Reflux: A Comparison of 2 Approaches

Various screening approaches have been proposed to identify the subgroup of children with urinary tract infection who have vesicoureteral reflux. However, few studies have compared the sensitivity of screening approaches in a representative population of young children. We compared the sensitivities of the top-down ((99m)technetium dimercaptosuccinic acid renal scan to screen) and biomarker based (C-reactive protein level at presentation) approaches in identifying children with vesicoureteral reflux. We calculated the sensitivity of the 2 screening approaches in detecting vesicoureteral reflux and subsequently high grade (III or greater) vesicoureteral reflux in children. The top-down and C-reactive protein based approaches missed 33% and 29% of cases of high grade vesicoureteral reflux, respectively. The sensitivity of the top-down approach for detecting high grade vesicoureteral reflux was lower than previously reported. Further study of novel methods to identify children at risk for renal scarring is warranted.

Urinary Tract Infection in Infants: A Single-Center Clinical Analysis in Southern Taiwan

This study summarized the epidemiology, etiology, and susceptibility of pathogens to antibiotics, and specific characteristics in infants aged less than 4 months diagnosed with urinary tract infection in the past decade in Taiwan. The medical charts of patients aged less than 4 months admitted for urinary tract infection to Kaohsiung Veterans General Hospital between January 2001 and December 2009 were retrospectively reviewed. A total of 132 patients, with male predominance (68.9%), were enrolled. The top three pathogens were similar to those identified in previous studies in Taiwan. The most common pathogen, Escherichia coli (85.3%), was resistant to ampicillin (75.9%), followed by sulfamethoxazole/trimethoprim (31.7%), and cefazolin (28.5%). Dimercaptosuccinic acid (DMSA) renal scan revealed 34.5% positive findings, while the vesicoureteral reflux (VUR) rate was 37.8% by direct radionuclide voiding cystography and/or voiding cysto-urethrography. Positive DMSA findings significantly correlated with VUR (p<0.001) and higher C-reactive protein level (p<0.05). E coli was the most common pathogen in the present cohort, and the top three pathogens were similar to those found in general pediatric population in Taiwan. VUR was the most common genitourinary tract anomaly in this age group. Positive DMSA was well correlated with VUR and higher C-reactive protein level.

1951 PERCUTANEOUS NEPHROLITHOTOMY FOR MANAGING RENAL CALCULI IN INFANTS A SINGLE-CENTER EXPERIENCE

You have accessJournal of UrologyStone Disease: New Technology/SWL, Ureteroscopic or Percutaneous Stone Removal IV1 Apr 20121951 PERCUTANEOUS NEPHROLITHOTOMY FOR MANAGING RENAL CALCULI IN INFANTS A SINGLE-CENTER EXPERIENCE Guohua Zeng, Zhigang Zhao, Jian Yuan, Chichang Shan, Wenzhong Cheng, Wenqi Wu, and Wen Zhong Guohua ZengGuohua Zeng Guangzhou, China, People's Republic of More articles by this author , Zhigang ZhaoZhigang Zhao Guangzhou, China, People's Republic of More articles by this author , Jian YuanJian Yuan Guangzhou, China, People's Republic of More articles by this author , Chichang ShanChichang Shan Guangzhou, China, People's Republic of More articles by this author , Wenzhong ChengWenzhong Cheng Guangzhou, China, People's Republic of More articles by this author , Wenqi WuWenqi Wu Guangzhou, China, People's Republic of More articles by this author , and Wen ZhongWen Zhong Guangzhou, China, People's Republic of More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2109AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES To report our experience with percutanous nephrolithotomy (PCNL) in infants with renal calculi, and evaluate its safety and efficacy in this age group. METHODS We retrospectively analyzed the medical and radiological records of infants (children under 3 years of age) with renal calculi who were treated by PCNL at our institution between November 2005 and August 2010. All PCNL was primary and with one puncture, using a 8/9.8Fr rigid ureteroscope. For stone removal, 14-18 Fr percutaneous tracts were established and stones were fragmented with a pneumatic lithotripter. Stone clearance and complications were recorded. RESULTS A total of 20 renal units in 19 infants (13 boys and 6 girls) received PCNL procedure for stone disease. The mean (range) age was 20.6 months (7-36 months). The mean (range) stone size was 2.2 (1.9-3.1) cm, and average (range) operative time was 77.5 (35-120) minutes. All patients were managed with only one tract. Stones were completely cleared in 84.2% of patients at a single session, which increased to 94.7% with a second look PCNL. The mean (range) hospital stay was 15.2 (7-31) days. No patients required blood transfusion. At a 4 to 61 months follow-up (average 27.2 months) 2 patients had recurrence of small renal stones (≤0.5 cm). Technetium diethylenetetramine-pentaacetic acid renal scan available in 13 cases before and after PCNL showed stabilization of the corresponding glomerular filtration rate (GFR) of the kidney (48.2±3.7 vs. 50.4±5.2 ml/minute, p=0.22). CONCLUSIONS PCNL is a safe and effective procedure for the treatment of infants with renal calculi. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e787 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Guohua Zeng Guangzhou, China, People's Republic of More articles by this author Zhigang Zhao Guangzhou, China, People's Republic of More articles by this author Jian Yuan Guangzhou, China, People's Republic of More articles by this author Chichang Shan Guangzhou, China, People's Republic of More articles by this author Wenzhong Cheng Guangzhou, China, People's Republic of More articles by this author Wenqi Wu Guangzhou, China, People's Republic of More articles by this author Wen Zhong Guangzhou, China, People's Republic of More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Downgrading of high-grade vesicoureteral reflux is a reliable option in the treatment of children with grade IV‒V reflux accompanied by breakthrough infections

PurposeTo evaluate incidence of urinary tract infection (UTI) and natural history of downgraded vesicoureteral reflux (VUR) in children with high-grade VUR following endoscopic correction. Materials and methodsWe retrospectively studied 54 children (13 males and 41 females) with a mean age of 1.8 years who underwent endoscopic correction of Grade IV‒V VUR due to breakthrough infections while on antibiotic prophylaxis.Reflux was Grade IV in 40 (74%) and V in 14 (26%) patients comprising 95 renal refluxing units (RRU). Reflux was corrected in 72 (76%) RRU. 18 (34%) patients/23 (24%) RRU demonstrated downgrading of VUR. 21 of the 23 RRU showed Grade II and 2 Grade III VUR, and were taken off antibiotic prophylaxis and allocated to observation. Patients were followed for 2–22 years (median 14 years). ResultsTechnetium 99m dimercaptosuccinic acid renal scan demonstrated preoperative renal scarring in 21 (78%) of the 23 RRU with downgraded VUR. None of the children developed febrile UTI after surgery. 1 RRU showed renal function deterioration. 8 (44%) of the 18 patients underwent follow-up voiding cystourethrogram, and in 7 (88%) there was either spontaneous resolution of VUR or downgrade to Grade I VUR. ConclusionsDowngrading of VUR is a reasonable option in patients with high-grade VUR suffering from breakthrough infections while on antibiotic prophylaxis. It leads to the cessation of febrile UTIs, further spontaneous resolution of VUR and may potentially avoid renal damage.

Managing children under 36 months of age with febrile urinary tract infection: a new approach

Recent guidelines on urinary tract infection (UTI) agree on reducing the number of invasive procedures. None of these has been validated by a long-term study. We describe our 11-years experience in the application of a diagnostic protocol that uses a reduced number of invasive procedures. We reviewed retrospectively the records of 406 children aged between 1 and 36 months at their first UTI. All patients underwent renal ultrasound (RUS). Children with abnormal RUS and those with UTI recurrences underwent voiding cystourethrography (VCUG) and dimercaptosuccinic acid (DMSA) renal scans. RUS after the first UTI was pathological in 7.4% children; 4.4 % had a second UTI. We performed 48 VCUG: 14 patients (29%) had vesicoureteral reflux (VUR), 12 of which showed an abnormal RUS while 2 had recurrent UTI. After DMSA renal scan renal damage appeared in only 6 of them (12.5%); all these children showed grade IV VUR. The application of our guidelines leads to a decrease in invasive examinations without missing any useful diagnoses or compromising the child's health.

Is a routine voiding cystourethrogram necessary in children after the first febrile urinary tract infection?

The aim of this study was to estimate the value of identifying vesicoureteral reflux (VUR) on a voiding cystourethrogram (VCUG) and the benefit of VUR management according to imaging strategies at the first febrile urinary tract infection (UTI). Children aged 1-144 months (n = 618) with the first febrile UTI admitted at our hospital from 2000 to 2009 were enrolled. In all patients, renal sonogram (US), (99m) Tc-dimercaptosuccinic acid (DMSA) renal scanning and VCUG were performed. Retrospective analyses per patient and per renal unit were performed. Abnormal US or DMSA scans had a sensitivity of 100% and a negative predictive value (NPV) of 100% to detect high-grade reflux. In hydronephrotic kidneys, DMSA scanning had a sensitivity of 88.2% and a NPV of 97.1% to detect high-grade reflux. Routine VCUG is not required after the first febrile UTI in patients with normal US or normal DMSA scan. Even if the US reveals hydronephrosis, routine VCUG is not necessary if the DMSA findings are normal. It is recommended that children who did not receive both a DMSA scan and VCUG after the first febrile UTI should be followed up over the long term.

Renal Function Change After Refluxing Type Orthotopic Ileal Substitution

We investigated the impact of the presence and severity of vesicoureteral reflux on renal function in patients with an ileal orthotopic bladder substitute without an antirefluxing mechanism after radical cystectomy. We compared results in patients with an ileal conduit. In 101 patients (195 renal units) who underwent radical cystectomy, including 73 (142 renal units) with an ileal orthotopic substitute and 28 (53 renal units) with a conduit between July 2004 and August 2009, we evaluated (99m)technetium diethylenetetramine pentaacetic acid renal scans to measure individual glomerular filtration rates preoperatively. This was followed annually along with postoperative voiding cystourethrography. We analyzed factors influencing a change in the postoperative glomerular filtration rate, including reflux presence and severity. In patients with an orthotopic substitute vesicoureteral reflux was observed in 104 renal units (73.2%). Reflux was bilateral in 80.8% of renal units and grade 3 or higher in 45 (31.7%). The mean glomerular filtration rate of all renal units remained unchanged perioperatively and was not influenced by reflux presence or severity. The percent change in the glomerular filtration rate was similar between patients with an orthotopic substitute and an ileal conduit. Post-void residual urine was a significant risk factor for febrile urinary tract infection and subsequent hydronephrosis in the absence of obstruction as well as an independent predictor of a significant glomerular filtration rate decrease (p = 0.009). Vesicoureteral reflux that develops in refluxing type urinary diversions does not significantly alter renal function regardless of its severity unless it is coupled with post-void residual urine. Post-void residual urine carries a significant risk of febrile urinary tract infection and it is an independent predictor of renal function deterioration.

Clinical course of vesicoureteral reflux in patients with hypospadias

The prevalence of vesicoureteral reflux (VUR) in hypospadic patients is reportedly higher than in healthy children. We investigated the prevalence and the clinical course of VUR in hypospadic patients. We carried out intraoperative cystography to detect VUR in 338 patients who underwent hypospadias repair. Age, severity of hypospadias and the presence of VUR were investigated. A dimercaptosuccinic acid renal scan and follow-up voiding cystourethrography (VCUG) were carried out if VUR was detected. VUR was detected in 41 patients (12.1%). Of 156 patients who were younger than 1 year-of-age, 34 (21.8%) were found to have VUR. The prevalence of VUR was significantly higher in patients younger than 1year (P<0.001), but was not associated with hypospadias type (P=0.212). The reflux grades were I, II and III in 6, 52 and 1 renal units, respectively. Renal scarring was shown in one of 36 patients. Follow-up VCUG was carried out in 30 patients at a mean of 14.28±3.89months, and reflux resolved in 27 and improved from grade II to grade I in three patients. Although its prevalence is higher in hypospadic children than in healthy children, it is not necessary to screen for VUR in hypospadic patients, because it is likely to be low-grade and to resolve in most cases.

The Role of Urinary Interleukin-8 Level in Diagnosis and Differentiation between Different Types of Urinary Tract Infection in Children

Background: Interleukin (IL)-8 acts as a potent neutrophils chemotactant responsible for the migration of neutrophils into the infected renal tissue to protect against invading pathogens. The aim of our work was to identify the role of urinary IL-8 in the diagnosis and differentiation between different forms of urinary tract infections (UTI) and its role in detection of the effect of treatment. Materials and Methods: Fifty children with different forms of UTI were evaluated and classified into three groups: Group I included 20 children diagnosed as having pyelonephritis (age range 6 months–10 years), Group II included 15 children with acute cystitis (age range 1–12 years) and Group III included 15 children with asymptomatic bacteruria (age range 5 months–10 years) and group III was considered as the control group as bacteriuria was detected during routine urine examination. All groups were urine culture positive. Inflammatory markers including erythrocyte sedimentation rate, C-reactive protein, leukocyte count, and urinary IL-8, together with the results of ultrasonography and dimercaptosuccinic acid renal scintigraphy (DMSA) were evaluated in these children. The ratios of urinary IL-8 to creatinine (IL-8/Cr) before and after the treatment at 72 hours were compared with each other. Results: The initial urine IL-8 concentrations were significantly higher in group I than in group II and also higher than group III (all p < 0.001). After 72 hours the urinary IL-8 level significantly decreased in all groups studied (all p < 0.001). There were positive correlations between urine IL-8 concentrations and leukocyturia in children with acute pyelonephritis (r = 0.43, p < 0.001). In children with the lower UTI group, no correlations were found between urine IL-8 values and leukocyturia. Renal injury was found in 6 children with pyelonephritis detected by dimercaptosuccinic acid renal scintigraphy scanning and these 6 patients had the highest level of urinary IL-8 among those of the pyelonephritis group after 6 months. Conclusion: From this study it is concluded that the importance of urinary IL-8 as a non-invasive test in diagnosis and differentiation between different forms of UTIs in children (upper UTI from lower UTI and from those with asymptomatic bacteruria) and also its importance in detection of treatment efficacy.

Endoscopic management of vesicoueteral reflux in adult women

• To describe our endoscopic management of adult women with vesicoureteral reflux (VUR) and associated outcomes. • We retrospectively identified 19 adult women who presented for the endoscopic treatment of VUR from November 2001 to January 2008. • Each patient was diagnosed with VUR by voiding cystourethrogram or nuclear cystourethrogram after an episode of pyelonephritis or recurrent urinary tract infections with renal scarring on ultrasound. • A dimercaptosuccinic acid renal scan was performed prior to treatment. All patients underwent endoscopic treatment with dextranomer/hyaluronic acid copolymer (Deflux). Patients with bilateral VUR received bilateral injections during the same procedure. • Follow-up imaging was obtained and success was strictly defined as no degree of VUR. Patients with residual VUR received repeat endoscopic treatment. • Nineteen patients with a mean age of 22 years old (range 18-33 years old) underwent endoscopic treatment for VUR. A total of 79% (15/19) had pre-existing risk factors for VUR, including prior open anti-reflux surgery (26%), family history of VUR (26%) and childhood diagnosis of VUR (26%). • Imaging revealed that 47% (9/19) had renal scarring and 26% (5/19) had bilateral VUR. The success rate was 79% (19/24) after one treatment, 92% (22/24) after 5 patients received a second treatment, and 96% (23/24) after 2 patients received a third treatment. There were no perioperative complications. • Endoscopic management of VUR is both safe and effective in adult women.

995 To Do or Not to Do: When the Latter is Better. A Cohort Study About Nice Guidelines in Uti

Background and aims: The guidelines from the National Institute for Health and Clinical Excellence (NICE 2007) on urinary tract infections (UTI) in childhood led to an epochal change in the management of children with UTI decreasing the number of instrumental evaluations. We used a protocol almost identical to that proposed by NICE. The aim of the study was to describe the 11 years follow-up of children with UTI and to validate our protocols.Methods: We enrolled 406 children (1-36 months) at their first UTI. All the children underwent renal ultrasounds (US). Children with pathological US and those with UTI recurrences underwent voiding cystourethrography (VCUG) and dimercaptosuccinic acid (DMSA) renal scans. All of them were clinically followed up.Results: US after the first episode of UTI were normal in 376 children (92.6%), pathological in 30 (7.4%). 18 patients had a second episode of UTI (4.4%). Second renal US were normal in all of them. We performed 48 VCUG: 30 in children with pathological US and 18 because of UTI recurrences. 14 children had VUR (29%): 12 had a pathological ultrasound and 2 had recurrent UTIs. The same children underwent DMSA scans: renal damage appeared only in 6 children (12.5%); all these children showed VUR of grade IV. The remaining 42 did not show any damage.Conclusions: Our study shows that application of NICE guidelines leads to a significant saving of invasive evaluations without compromising child health. Moreover our data confirm that is unreasonable searching VUR since the first episode of UTI.

5-Year Prospective Results of Dimercapto-Succinic Acid Imaging in Children With Febrile Urinary Tract Infection: Proof That the Top-Down Approach Works

Evaluation in children after febrile urinary tract infection involves voiding cystourethrogram, which emphasizes urinary reflux rather than renal risk. We believe that early dimercapto-succinic acid renal scan after febrile urinary tract infection predicts clinically significant reflux and which children should undergo voiding cystourethrogram. The criticism of this approach is that some reflux and preventable renal damage would be missed. This study validates the use of initial dimercapto-succinic scan and presents 5-year renal outcomes. We prospectively studied children with febrile urinary tract infection using initial dimercapto-succinic acid renal scan, voiding cystourethrogram and renal/bladder ultrasound. Children with anatomical or neurological genitourinary abnormality and protocol failures were excluded from analysis. Dimercapto-succinic acid scan was repeated at 6 months if initially abnormal. Followup was done every 6 months in all children for at least 5 years. A total of 121 children fit study inclusion criteria and completed the 5-year study. Overall 88 initial dimercapto-succinic acid scans (73%) were abnormal and 78 children (64%) had urinary reflux. The OR of having clinically significant reflux predicted by abnormal initial scan was 35.4. Abnormal followup scan did not predict clinically significant reflux. Overall subsequent urinary tract infection developed in 32 patients (26.5%) and 27 (85%) had an abnormal initial scan. No child with a normal initial scan had clinically significant reflux. Dimercapto-succinic acid scan can predict clinically significant reflux and children at greatest renal risk. Initial dimercapto-succinic acid scan should be done in all children after febrile urinary tract infection while voiding cystourethrogram should be reserved for those with an abnormal initial dimercapto-succinic acid scan.

Tc-99m-Dimercaptosuccinic Acid and Tc-99m Diethylenetriamine Pentaacetic Acid Renal Scan Detect “Reverse Horseshoe Kidney”

We report a case of a 6-year boy presenting with abdominal pain and a culture proven to be recurrent urinary tract infections. His hemoglobin and kidney function tests were normal. Tc-99m dimercaptosuccinic acid renal scan demonstrated fusion of the upper poles of the kidneys with a functional isthmus and no parenchymal scar. Tc-99m diethylenetriamine pentaacetic acid with diuresis also showed upper pole fusion with no obstruction. The present case highlights the use of functional renal imaging in detecting a congenital anomaly of a horseshoe kidney with upper pole fusion (reverse horseshoe kidney).

Change in Renal Function After Laparoscopic Donor Nephrectomy for Kidney Transplantation

BackgroundLaparoscopic donor nephrectomy (LDN) has become the method of choice for living-donor kidney transplantation. However, LDN may result in decreased renal function in the donor, and risk of end-stage renal failure has been reported. ObjectiveTo evaluate changes in renal function after LDN. Patients and MethodsThe study included 51 living donors of renal transplants between March 2002 and December 2008. Before kidney donation, we computed the initial function of the kidney preserved in the donor using 24-hour creatinine clearance (Ccr) and functional ratio as revealed at technetium 99m dimercaptosuccinic acid renal scanning. After kidney donation, serum creatinine concentration (sCr) and Ccr were calculated on postoperative day 2 and every 3 months thereafter. ResultsAfter LDN, mean sCr increased immediately, from 0.90 to 1.31, as did Ccr of the kidney preserved in the donor, from 58.2 to 79.6, a 36.9% increase. A greater percent increase in function was observed in younger donors and those with lower initial Ccr of the preserved kidney. Although 9.8% of donors demonstrated slightly decreased renal function of the preserved kidney at last follow-up, renal function was adequately preserved in most donors. ConclusionYounger donors and those with lower initial function of the preserved kidney before nephrectomy demonstrate a greater increase in function after nephrectomy. Age might be a risk factor for decreased renal function after LDN. Older potential living donors may need more careful evaluation before kidney donation.

The Growing Role of Ultrasonography in Evaluating Children After Urinary Tract Infection

The purpose of this review is to advocate the use of ultrasonography (US) techniques in the work-up of children after a urinary tract infection (UTI). Currently, two major approaches are recognized. The first approach recommends looking for vesicoureteral reflux (VUR) in all children following a UTI. New techniques have been developed where, in the majority of cases, x-ray voiding cystourethrography (VCUG) is first substituted with radionuclide voiding cystography, and finally with echo-enhanced voiding urosonography, and this presented a significant improvement in diminishing the radiation burden on patients; yet there remained the drawback that catheterization is still necessary with all of these techniques. The introduction of catheter-free procedures would be a ‘final solution’, but these are yet to be validated. The second approach recommends screening for scars (mostly using a dimercaptosuccinic acid renal scan), while cystographies (preferably VCUG) are only performed in cases in which renal scarring has been confirmed. It was demonstrated that a dimercaptosuccinic acid renal scan can be safely and efficiently replaced by US, while voiding urosonography can substitute VCUG in children with confirmed scars in whom one believes VUR should be sought. From here on, catheter-free US techniques for VUR detection, although promising a ‘final solution’, still remain to be validated. In conclusion, regardless of which approach one believes is more appropriate in the management of children following a UTI, it is obvious that both protocols can be sufficiently fulfilled by the use of US techniques. At this time, more studies are needed to properly validate the latest noninvasive (catheter-free) US techniques for VUR detection.

Urinary Neutrophil-Gelatinase Associated Lipocalin is a Potential Noninvasive Marker for Renal Scarring in Patients With Vesicoureteral Reflux

Renal scarring is a serious complication that often occurs with chronic pyelonephritis in the presence of vesicoureteral reflux. In a previous study we established a rat model of renal scarring in which we found the up-regulation of neutrophil-gelatinase associated lipocalin at the mRNA and protein levels. In this study we evaluated urinary neutrophil-gelatinase associated lipocalin as a potential biomarker for progression of renal scarring in patients with vesicoureteral reflux. A total of 34 patients diagnosed with vesicoureteral reflux without evidence of current urinary tract infection and 28 normal healthy children were enrolled in this study. Renal scars were evaluated by (99m)technetium dimercapto-succinic acid renal scan in 24 of the reflux cases. Urinary neutrophil-gelatinase associated lipocalin levels were monitored by ELISA. In normal subjects urinary neutrophil-gelatinase associated lipocalin was high during infancy, decreased rapidly within the following year and reached a low stable level from age 3 years onward. Urinary neutrophil-gelatinase associated lipocalin levels, normalized to age matched standards, were significantly increased in patients with vesicoureteral reflux compared to controls. These levels did not correlate with reflux grade, but were significantly higher in patients with radiological evidence of renal scarring irrespective of reflux grade. Estimation of urinary neutrophil-gelatinase associated lipocalin may be useful as a noninvasive diagnostic or prognostic biomarker for renal scarring.

Reply

AJR 2010; 194:W1 0361–803X/10/1942–W1 © American Roentgen Ray Society Radiation Dose and Screening for Vesicoureteral Reflux We read with interest the review by Dr. Lim [1] concerning recent advances in the diagnosis of vesicoureteral reflux (VUR). The article provides an otherwise excellent review of the current controversy regarding VUR screening methods; however, we are concerned by the lack of attention given to the radiation dose from 99mTc-dimercaptosuccinic acid (DMSA) renal scans. At our institution, a DMSA renal scan performed in a 1-year-old child carries a 1.3-fold higher radiation dose than continuous fluoroscopy voiding cystourethrography (VCUG), a 10-fold higher radiation dose than pulsed fluoroscopy VCUG, and a 200-fold higher radiation dose than radionuclide cystography [2]. Importantly, because of the lack of clinical guidelines or standardized dosimetry, there is marked variation in the administered radiation dose for children undergoing nuclear medicine scans [3]. As a result, these figures may, in fact, underestimate the excess radiation dose associated with a systemic abandonment of the bottom-up (i.e., early cystography) approach in favor of the top-down (i.e., early DMSA scan) approach. It has been postulated that adoption of the top-down approach would result in a decrease in the number of patients diagnosed with VUR who are not actually at risk of renal damage, clearly a worthy and admirable goal. However, relatively little evidence is yet available to support this claim, and both the American Academy of Pediatrics and the American Urological Association continue to recommend the bottom-up approach in screening children at risk of VUR [4, 5]. Thus, a commitment to the as low as reasonably achievable (ALARA) principle for our young patients would seem to suggest that providers should shift to the topdown approach only after a preponderance of evidence shows that the clinical benefits merit the inevitable accompanying increase in radiation dose. Jonathan C. Routh Richard S. Lee Jeanne S. Chow Children’s Hospital Boston Harvard Medical School Boston, MA

Radiation Dose and Screening for Vesicoureteral Reflux

AJR 2010; 194:W1 0361–803X/10/1942–W1 © American Roentgen Ray Society Radiation Dose and Screening for Vesicoureteral Reflux We read with interest the review by Dr. Lim [1] concerning recent advances in the diagnosis of vesicoureteral reflux (VUR). The article provides an otherwise excellent review of the current controversy regarding VUR screening methods; however, we are concerned by the lack of attention given to the radiation dose from 99mTc-dimercaptosuccinic acid (DMSA) renal scans. At our institution, a DMSA renal scan performed in a 1-year-old child carries a 1.3-fold higher radiation dose than continuous fluoroscopy voiding cystourethrography (VCUG), a 10-fold higher radiation dose than pulsed fluoroscopy VCUG, and a 200-fold higher radiation dose than radionuclide cystography [2]. Importantly, because of the lack of clinical guidelines or standardized dosimetry, there is marked variation in the administered radiation dose for children undergoing nuclear medicine scans [3]. As a result, these figures may, in fact, underestimate the excess radiation dose associated with a systemic abandonment of the bottom-up (i.e., early cystography) approach in favor of the top-down (i.e., early DMSA scan) approach. It has been postulated that adoption of the top-down approach would result in a decrease in the number of patients diagnosed with VUR who are not actually at risk of renal damage, clearly a worthy and admirable goal. However, relatively little evidence is yet available to support this claim, and both the American Academy of Pediatrics and the American Urological Association continue to recommend the bottom-up approach in screening children at risk of VUR [4, 5]. Thus, a commitment to the as low as reasonably achievable (ALARA) principle for our young patients would seem to suggest that providers should shift to the topdown approach only after a preponderance of evidence shows that the clinical benefits merit the inevitable accompanying increase in radiation dose. Jonathan C. Routh Richard S. Lee Jeanne S. Chow Children’s Hospital Boston Harvard Medical School Boston, MA

The Clinical Significance of Intrarenal Reflux in Voiding Cystourethrography (VCUG)

PurposeIntrarenal reflux (IRR) occurs in 3-10% of cases of total reflux and can lead to renal injury, which may eventually result in renal scarring. In this study, we evaluated the clinical importance of IRR detected by voiding cystourethrography and evaluated the relationship between IRR and renal scarring.Materials and MethodsFrom January 2002 to May 2008, 50 patients who were diagnosed with vesicoureteral reflux (VUR) and showed IRR in voiding cystourethrography were enrolled. IRR was seen in 59 renal units in our enrolled patients. A 99mTc 2,3-dimercaptosuccinic acid (DMSA) renal scan was performed after VUR was detected in all cases. Nine patients were conservatively treated with prophylactic antibiotics, whereas 41 patients received an anti-reflux operation. A follow-up renal scan was performed after 3 to 6 months to check for any changes in renal scarring.ResultsThe average patient age was 9.2 months (range, 1-42 months). Forty-nine patients were male; only one patient was female. The mean duration until surgery was 2.9 months. Generally, the IRR sites corresponded to the sites of photon defects on DMSA renal scans (76.3%). Furthermore, the photon defects on IRR sites tended to progress to renal scarring (65.2%). The rate of change in scarring was lower in the surgery group (47.1%) than in the prophylactic antibiotic group (75%).ConclusionsIRR sites and the sites of photon defects on DMSA renal scans showed a high correspondence, and these sites tended to progress to renal scarring. We suggest that VUR with IRR should be actively managed to decrease the chances of renal scarring.

Modified Differential Renal Function Measurement Revised by Renal Cross Sectional Area in Children with Ureteropelvic Junction Obstruction

PurposeDiuretic 99mTc-diethylenetriaminepentaacetic acid (Tc-DTPA) renal scans may show false-negative or false-positive results in children with ureteropelvic junction obstruction (UPJO). We evaluated whether modified differential renal function (DRF) revised by the renal cross-sectional area on imaging study may be a more valuable predictor than conventional DRF on a renal scan for deciding on a proper interventional time.Materials and MethodsBetween September 2001 and January 2008, we reviewed the diuretic renal scan results of 29 pediatric patients who underwent pyeloplasty due to unilateral UPJO. Diuretic renal scans using the standard 99mTc-DTPA protocol and imaging studies for renal unit measurement area were done. Conventional DRF measurement and modified calculation of DRF per unit area were done. Conventional DRF was classified into group I (below 40%) and group II (above 40%).ResultsThe mean age of all patients was 42.6±52.6 months (range, 3-198 months). The mean cross-sectional areas of the UPJO kidney and of the normal contralateral kidney were 62.1±29.2 cm2 and 41.3±22.5 cm2, respectively (p<0.01). The conventional and modified DRF of the UPJO kidney were 45.2±9.2% and 35.2±9.5%, respectively (p<0.01). Thirteen children (62%) in group II (n=21) were classified in group I by the modified DRF measurement.ConclusionsThe modified DRF measurement calculated according to cross-sectional area showed fewer false-negative results and may be a valuable method for deciding on pyeloplasty under equivocal circumstances.