Hydronephrotic lower moiety of duplex systems: Observations using diuresis renography

PURPOSE

The purpose of this study is to characterize the prevalence and behavior of hydronephrosis of non-refluxing lower moiety of duplex kidneys using MAG-3 diuresis renography. We compare our data to previous case series and ureteropelvic junction obstruction of single systems.

MATERIALS AND METHODS

An IRB-approved database of over 5000 diuresis renograms performed in 2025 patients was queried to identify cases of hydronephrosis of lower moiety of duplex kidneys suspicious for ureteropelvic obstruction, excluding those with hydroureter or reflux. Kidney function and post-furosemide drainage parameters on initial and follow-up diuresis renograms were recorded. Medical records and patient outcomes were reviewed.

RESULTS

In total, 19 renal units were identified in 18 patients (11 male, 7 female), age range 0.5 months to 17.8 years, including one patient with bilateral lower moiety hydronephrosis. Initial diuresis renograms in 12 asymptomatic patients (13 renal units) with antenatal hydronephrosis demonstrated varying drainage patterns from normal to obstructed. Follow-up studies showed worsening drainage in 3 patients, who all underwent surgery. Drainage improved in 4 patients and remained unchanged in 5 patients (6 renal units). Of the 6 patients presenting with Dietl's crisis, 5 showed obstructive drainage on initial diuresis renogram, 2/5 with decreased function. All 5 obstructed patients underwent surgery.

CONCLUSION

Hydronephrosis of the lower moiety of a duplex system is rare and behaves similarly to single systems. The majority are diagnosed antenatally, display a dynamic nature, and may present with acute obstruction. Diuresis renography is a valuable tool in its evaluation and management.

Gastric emptying of milk in infants and children up to 5 years of age: normative data and influencing factors

BACKGROUND

Gastric emptying scintigraphy is widely used in infants and children, but there is a lack of age-specific normative data.

OBJECTIVE

The objectives of this retrospective study were: 1) to establish a range of gastric emptying of milk or formula as a surrogate for normal gastric emptying in infants and young children ≤5 years of age, and 2) to investigate the effects of patient age, feeding volume, feeding route and gastroesophageal reflux on gastric emptying.

MATERIALS AND METHODS

The reports of 5,136 gastric emptying studies of children ≤5 years of age performed at Children's National Medical Center from January 1990 to August 2012 were reviewed. Demographic data, 1-h and 3-h gastric emptying values and gastroesophageal reflux status of all patients were stored in a database. Using stringent inclusion and exclusion criteria, the studies of patients as similar to healthy children as possible were selected for this study.

RESULTS

The study group included 2,273 children (57% male) ages 0-59 months (median: 4.6 months). The median 1-h gastric emptying was 43% (interquartile range [IQR] 34-54%). The median 3-h gastric emptying was 91% (IQR 79-98%). Sixty-one percent of patients with 1-h gastric emptying value of <50% had 3-h gastric emptying ≥80%. Gastric emptying was significantly faster in children ≤6 months as compared with all older age groups. In each age group, the median gastric emptying decreased with increasing feeding volume. Gastric emptying was significantly faster in patients fed via combined nasogastric tube and oral routes as compared with those fed exclusively orally. There was no significant difference in gastric emptying of children with and without gastroesophageal reflux.

CONCLUSION

Although there are statistically significant differences in gastric emptying based on age, volume and route of feeding, the data suggest that overall normal liquid gastric emptying in infants and children ≤5 years of age is ≥80% at 3 h. One-hour emptying measurements are not reliable for detecting delayed gastric emptying.

Biomarkers that differentiate false positive urinalyses from true urinary tract infection

BACKGROUND

The specificity of the leukocyte esterase test (87%) is suboptimal. The objective of this study was to identify more specific screening tests that could reduce the number of children who unnecessarily receive antimicrobials to treat a presumed urinary tract infection (UTI).

METHODS

Prospective cross-sectional study to compare inflammatory proteins in blood and urine samples collected at the time of a presumptive diagnosis of UTI. We also evaluated serum RNA expression in a subset.

RESULTS

We enrolled 200 children; of these, 89 were later demonstrated not to have a UTI based on the results of the urine culture obtained. Urinary proteins that best discriminated between children with UTI and no UTI were involved in T cell response proliferation (IL-9, IL-2), chemoattractants (CXCL12, CXCL1, CXCL8), the cytokine/interferon pathway (IL-13, IL-2, INFγ), or involved in innate immunity (NGAL). The predictive power (as measured by the area under the curve) of a combination of four urinary markers (IL-2, IL-9, IL-8, and NGAL) was 0.94. Genes in the pathways related to inflammation were also upregulated in serum of children with UTI.

CONCLUSIONS

Urinary proteins involved in the inflammatory response may be useful in identifying children with false positive results with current screening tests for UTI; this may reduce unnecessary treatment.

Host and Bacterial Markers that Differ in Children with Cystitis and Pyelonephritis

OBJECTIVE

To determine whether treatment for urinary tract infections in children could be individualized using biomarkers for acute pyelonephritis.

STUDY DESIGN

We enrolled 61 children with febrile urinary tract infections, collected blood and urine samples, and performed a renal scan within 2 weeks of diagnosis to identify those with pyelonephritis. Renal scans were interpreted centrally by 2 experts. We measured inflammatory proteins in blood and urine using LUMINEX or an enzyme-linked immunosorbent assay. We evaluated serum RNA expression using RNA sequencing in a subset of children. Finally, for children with Escherichia coli isolated from urine cultures, we performed a polymerase chain reaction for 4 previously identified virulence genes.

RESULTS

Urinary markers that best differentiated pyelonephritis from cystitis included chemokine (C-X-C motif) ligand (CXCL)1, CXCL9, CXCL12, C-C motif chemokine ligand 2, INF γ, and IL-15. Serum procalcitonin was the best serum marker for pyelonephritis. Genes in the interferon-γ pathway were upregulated in serum of children with pyelonephritis. The presence of E coli virulence genes did not correlate with pyelonephritis.

CONCLUSIONS

Immune response to pyelonephritis and cystitis differs quantitatively and qualitatively; this may be useful in differentiating these 2 conditions.

Diuresis renography in the evaluation and management of pediatric hydronephrosis: What have we learned?

Diuresis renography (DR) is widely used in the evaluation of hydronephrosis and hydroureter in infants and children. The goal of this provocative nuclear imaging examination should be to detect the hydronephrotic kidneys at risk for loss of function and development of pain, hematuria, and urinary tract infection. The reliability of DR is dependent on the acquisition and processing of the data as well as interpretation and utilization of the results. In this review, the key concepts of standardized DR and pitfalls to avoid are highlighted.

Glomerular hyperfiltration in children with cancer: prevalence and a hypothesis

BACKGROUND

Glomerular hyperfiltration has recently been reported in children with malignancies and has been attributed to increased solute from breakdown of tumor tissues.

OBJECTIVE

To evaluate the prevalence of hyperfiltration in the pediatric oncology population and explore its pathophysiological mechanism.

MATERIALS AND METHODS

Tc-99 m diethylenetriaminepentaacetic acid (DTPA) glomerular filtration rate (GFR) examinations (437 studies) and medical records of 177 patients <21 years of age diagnosed with a malignancy between January 2005 and October 2013 were retrospectively reviewed. Hyperfiltration was defined as a GFR ≥ 160 ml/min/1.73 m².

RESULTS

Seventy-seven (43.5%) patients had hyperfiltration in at least one GFR exam. A significantly higher percentage of patients with central nervous system (CNS) tumors (63.6%) had hyperfiltration when compared to other tumor types (27.3%, P < 0.001). No association was found between hyperfiltration and age, gender, race or bone marrow involvement. There was a significant trend toward decreasing hyperfiltration after the second cycle of chemotherapy (P = 0.006) and a significant increase in subjects with low GFR (<100 ml/min/1.73 m²) with increasing number of cycles of chemotherapy (P = 0.005).

CONCLUSION

Glomerular hyperfiltration is common in children with malignancies at diagnosis and during initial cycles of chemotherapy. It is particularly prevalent in patients with central nervous tumors, which are frequently smaller in volume. Therefore, the pathophysiological mechanism of hyperfiltration cannot be explained solely on the basis of large tumor volume and subsequent cell breakdown. We hypothesize that host hypermetabolic state plays an important role in pathophysiology of hyperfiltration.

Early Antibiotic Treatment for Pediatric Febrile Urinary Tract Infection and Renal Scarring

IMPORTANCE

Existing data regarding the association between delayed initiation of antimicrobial therapy and the development of renal scarring are inconsistent.

OBJECTIVE

To determine whether delay in the initiation of antimicrobial therapy for febrile urinary tract infections (UTIs) is associated with the occurrence and severity of renal scarring.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study that combined data from 2 previously conducted longitudinal studies (the Randomized Intervention for Children With Vesicoureteral Reflux trial and the Careful Urinary Tract Infection Evaluation Study). Children younger than 6 years with a first or second UTI were followed up for 2 years.

EXPOSURE

Duration of the child's fever prior to initiation of antimicrobial therapy for the index UTI.

MAIN OUTCOMES AND MEASURES

New renal scarring defined as the presence of photopenia plus contour change on a late dimercaptosuccinic acid renal scan (obtained at study exit) that was not present on the baseline scan.

RESULTS

Of the 482 children included in the analysis, 434 were female (90%), 375 were white (78%), and 375 had vesicoureteral reflux (78%). The median age was 11 months. A total of 35 children (7.2%) developed new renal scarring. Delay in the initiation of antimicrobial therapy was associated with renal scarring; the median (25th, 75th percentiles) duration of fever prior to initiation of antibiotic therapy in those with and without renal scarring was 72 (30, 120) and 48 (24, 72) hours, respectively (P = .003). Older age (OR, 1.03; 95% CI, 1.01-1.05), Hispanic ethnicity (OR, 5.24; 95% CI, 2.15-12.77), recurrent urinary tract infections (OR, 0.97; 95% CI, 0.27-3.45), and bladder and bowel dysfunction (OR, 6.44; 95% CI, 2.89-14.38) were also associated with new renal scarring. Delay in the initiation of antimicrobial therapy remained significantly associated with renal scarring even after adjusting for these variables.

CONCLUSIONS AND RELEVANCE

Delay in treatment of febrile UTIs and permanent renal scarring are associated. In febrile children, clinicians should not delay testing for UTI.

Renal Scarring in the Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) Trial

BACKGROUND AND OBJECTIVES

The main objectives of the Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) trial were to evaluate the role of antimicrobial prophylaxis in the prevention of recurrent urinary tract infection (UTI) and renal scarring in children with vesicoureteral reflux (VUR). We present a comprehensive evaluation of renal scarring outcomes in RIVUR trial participants.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This multicenter, randomized, placebo-controlled trial enrolled 607 children aged 2-71 months with grade 1-4 VUR diagnosed after a first or second febrile or symptomatic UTI. Study participants received trimethoprim-sulfamethoxazole or placebo and were followed for 2 years. Renal scarring was evaluated by baseline and follow-up (99m)technetium dimercaptosuccinic acid (DMSA) renal scans that were reviewed independently by two blinded reference radiologists.

RESULTS

At the end of the study, 58 (10%) of 599 children and 63 (5%) of 1197 renal units had renal scarring. New renal scarring did not differ between the prophylaxis and placebo groups (6% versus 7%, respectively). Children with renal scarring were significantly older (median age, 26 versus 11 months; P=0.01), had a second UTI before enrollment (odds ratio [OR], 2.85; 95% confidence interval [95% CI], 1.38 to 5.92), were more likely to be Hispanic (OR, 2.22; 95% CI, 1.13 to 4.34), and had higher grades of VUR (OR, 2.79; 95% CI, 1.56 to 5.0). The proportion of new scars in renal units with grade 4 VUR was significantly higher than in units with no VUR (OR, 24.2; 95% CI, 6.4 to 91.2).

CONCLUSIONS

Significantly more renal scarring was seen in relatively older children and in those with a second episode of febrile or symptomatic UTI before randomization. Preexisting and new renal scars occurred significantly more in renal units with grade 4 VUR than in those with low-grade or no VUR. Antimicrobial prophylaxis did not decrease the risk of renal scarring.

The "flowerpot" sign: inference of poor renal function in high grade vesicoureteral reflux by calyceal orientation

INTRODUCTION/OBJECTIVE

Modern radiographic advances have allowed for detailed and accurate imaging of not only urologic anatomy but also urologic function. The art of observational inference of subtle anatomic features and function from a static radiograph is being traded for new, more precise, and more expensive modalities. While the superiority of these methods cannot be denied, the total information provided in simpler tests should not be ignored. The relationship between high grade vesicoureteral reflux with the dilated calyces arranged cephalad to a dilated funnel-shaped renal pelvis on VCUG and reduced differential renal function has not been previously described, but has been anecdotally designated a "flowerpot" sign by our clinicians. We hypothesize that the appearance of a "flowerpot" kidney as described herein is an indicator of poor renal function in the setting of high grade VUR.

STUDY DESIGN

IRB approval was obtained and 315 patients were identified from system-wide VCUG reports from 2004-2012 with diagnosed "high grade" or "severe" vesicoureteral reflux. Inclusion into the study required grade IV or V VUR on initial VCUG and an initial radionuclide study for determination of differential function. Patients with a solitary kidney, posterior urethral valve, multicystic dysplastic kidney, renal ectopia, or duplex collecting systems were excluded. Grade of reflux, angle of the inferior-superior calyceal axis relative to the lumbar spine, and differential uptake were recorded along with presence of the new "flowerpot" sign. Variables were analyzed using the Mann-Whitney U test to determine statistical significance.

RESULTS

Fifty seven patients met inclusion criteria with 11 being designated as "flowerpot" kidneys. These "flowerpot" kidneys could be objectively differentiated from other kidneys with grade IV and/or grade V VUR both by inferior-superior calyceal axis (median angle, 52° [37-66] vs. 13° [2-37], respectively p < 0.001) and by differential renal uptake (median, 23% [5-49] vs. 45% [15-81], respectively p < 0.001). Likewise, there was no difference between either calyceal axis (median angle, 13° [3-20] vs. 13° [2-37]) or differential function (median, 48% [24-81] vs. 40% [15-66], p = 0.129) when comparing kidneys with grade IV and grade V VUR, respectively, that did not demonstrate the "flowerpot" sign.

DISCUSSION/CONCLUSION

Grading of VUR is used to provide a common language for scientific discussion and determine prognosis for children with similar attributes. The dysmorphic calyceal system in the "flowerpot" kidneys supports the theory of abnormal renal blastema induction associated with abnormal differentiation of the ureteral bud. Even in the absence of urinary tract infections and/or pyelonephritis, renal abnormalities and decreased differential function can be observed on renal scintigraphy. This study also confirms the male predominance and functional similarities between grade 4 and 5 refluxing renal units. Recognizing this is a limited observational study based on imaging alone, the "flowerpot" sign is an indicator of the most severe form of grade 5 VUR but is only one factor in predicting long term overall renal prognosis. However, 14% (8/57) of our cohort had a relative uptake of less than 20% with 5 of these exhibiting the "flowerpot" sign. The "flowerpot" sign on VCUG can be used as indirect evidence of poor differential renal function and, therefore, useful in guiding parental expectations prior to formal functional imaging.

Phenobarbital-enhanced hepatobiliary scintigraphy in the diagnosis of biliary atresia: two decades of experience at a tertiary center

BACKGROUND

Hepatobiliary scintigraphy is highly sensitive for diagnosing biliary atresia; however, its specificity has varied in the literature from 35% to 97%.

OBJECTIVE

The purpose of this study was to re-evaluate the accuracy of phenobarbital-enhanced hepatobiliary scintigraphy in differentiating biliary atresia from other causes of neonatal cholestasis.

MATERIALS AND METHODS

We retrospectively reviewed all hepatobiliary scans of infants with cholestasis at our institution from December 1990 to May 2011. Per our routine protocol the scans were obtained after pretreatment with phenobarbital (5 mg/kg/day for 5 days) to achieve a serum level of ≥15 mcg/ml. Normal hepatic uptake with no biliary excretion by 24 h was considered consistent with biliary atresia.

RESULTS

One hundred eighty-six infants with 210 hepatobiliary scans composed the study group. Forty-three (23%) infants had the final diagnosis of biliary atresia. Hepatobiliary scintigraphy was 100% sensitive, 93% specific and 94.6% accurate in diagnosing biliary atresia. Of the 186, 39/111 (35.1%) term and 2/68 (2.9%) preterm infants had biliary atresia; two of seven children with unknown gestational age also had biliary atresia. Other diagnoses included neonatal hepatitis, total parenteral nutrition cholestasis, Alagille syndrome, cystic fibrosis, choledochal cyst, hypothyroidism, alpha-1 antitrypsin deficiency and persistent cholestasis of unknown etiology.

CONCLUSION

Phenobarbital-enhanced hepatobiliary scintigraphy is highly accurate in differentiating biliary atresia from other causes of neonatal cholestasis. Biliary atresia is rare in premature infants.

Two-phase whole-body skeletal scintigraphy in children--revisiting the usefulness of the early blood pool phase

The usefulness of whole-body blood pool imaging as part of Tc-99m methylene diphosphonate (MDP) skeletal scintigraphy in detection of marrow infiltrative processes and unexpected soft-tissue and visceral abnormalities is demonstrated via illustrative case examples. Technical aspects of this simple and fast scanning technique are also highlighted.

Scintigraphic features of duplex kidneys on DMSA renal cortical scans

The spectrum of manifestations of duplex kidneys on (99m)Tc-dimercaptosuccinic acid (DMSA) renal cortical scans and correlating findings on other imaging modalities are presented. Relevant embryology of the duplex systems and technical aspects of DMSA scintigraphy are reviewed.

Effective reduction of brown fat FDG uptake by controlling environmental temperature prior to PET scan: an expanded case series

INTRODUCTION

Brown fat uptake of 2-deoxy-2-[F-18]fluoro-D: -glucose (FDG) on a positron emission tomography (PET) scan may limit the ability to assess for cancer. Previously, Garcia et al. demonstrated in ten patients a significant decrease in brown fat uptake of 2-deoxy-2-[F-18]fluoro-D: -glucose (FDG) after controlling the patient's environmental temperature.

OBJECTIVE

The objective of the current study is to validate the effectiveness of controlled environmental temperature (CET) to reduce physiologic brown fat (BF) FDG uptake on a PET scan in a larger series.

METHOD

A retrospective review was performed from January 2002 to October 2007 of patients who had (1) a pattern of FDG uptake on PET scan consistent with BF, (2) no evidence of cancer by computed tomography in the regions of interest noted below, (3) repeat scan with CET within 4 months of the 1st PET scan, and (4) no use of drugs reported to reduce BF FDG uptake (e.g., benzodiazepine, beta-blockers, reserpine) unless they were used identically prior to and during both studies. The FDG-PET and controlled environmental temperature-positron emission tomography (CET-PET) scans were performed as per protocol. The non-CET and CET-PET images were blinded/randomized, and three physicians assessed three regions (right neck, left neck, and paraspinal area) semiquantitatively using the following scale: "0" (background [bkgd]), 1 + (> bkgd < liver), 2 + (equal to liver), 3 + (> liver). Standard uptake value (SUV) data was recorded. Results were analyzed using a two-tailed t test.

RESULTS

Of 8,640 FDG-PET scans performed, 30 patients (four male, 26 female) met the above criteria. The median age was 36 years (range, 12-60 years). The mean (± 1 standard deviation) of differences in the scores between the two studies for right neck, left neck, and paraspinal regions, respectively, were for reader 1:(2.1 ± 1.37), (1.95 ± 1.43), and (1.85 ± 1.26); reader 2 (2.3 ± 1.40), (1.70 ± 1.13), and (1.77 ± 1.13); reader 3 (2.17 ± 1.17), (2.20 ± 1.18), and (0.50 ± 1.30); for maximum SUV score (3.4 ± 2.9), (3.3 ± 2.9), and (1.77 ± 1.13). All p values were <0.001.

CONCLUSION

In this larger series, CET effectively reduced the false-positive (18)FDG uptake in BF on PET scans without the use of drugs.

Importance of methodology on (99m)technetium dimercapto-succinic acid scintigraphic image quality: imaging pilot study for RIVUR (Randomized Intervention for Children With Vesicoureteral Reflux) multicenter investigation

PURPOSE

We reviewed our experience with (99m)technetium dimercapto-succinic acid scintigraphy obtained during an imaging pilot study for a multicenter investigation (Randomized Intervention for Children With Vesicoureteral Reflux) of the effectiveness of daily antimicrobial prophylaxis for preventing recurrent urinary tract infection and renal scarring. We analyzed imaging methodology and its relation to diagnostic image quality.

MATERIALS AND METHODS

(99m)Technetium dimercapto-succinic acid imaging guidelines were provided to participating sites. High-resolution planar imaging with parallel hole or pinhole collimation was required. Two core reviewers evaluated all submitted images. Analysis included appropriate views, presence or lack of patient motion, adequate magnification, sufficient counts and diagnostic image quality. Inter-reader agreement was evaluated.

RESULTS

We evaluated 70, (99m)technetium dimercapto-succinic acid studies from 14 institutions. Variability was noted in methodology and image quality. Correlation (r value) between dose administered and patient age was 0.780. For parallel hole collimator imaging good correlation was noted between activity administered and counts (r = 0.800). For pinhole imaging the correlation was poor (r = 0.110). A total of 10 studies (17%) were rejected for quality issues of motion, kidney overlap, inadequate magnification, inadequate counts and poor quality images. The submitting institution was informed and provided with recommendations for improving quality, and resubmission of another study was required. Only 4 studies (6%) were judged differently by the 2 reviewers, and the differences were minor.

CONCLUSIONS

Methodology and image quality for (99m)technetium dimercapto-succinic acid scintigraphy varied more than expected between institutions. The most common reason for poor image quality was inadequate count acquisition with insufficient attention to the tradeoff between administered dose, length of image acquisition, start time of imaging and resulting image quality. Inter-observer core reader agreement was high. The pilot study ensured good diagnostic quality standardized images for the Randomized Intervention for Children With Vesicoureteral Reflux investigation.

Reduction of Brown Fat 2-Deoxy-2-[F-18]fluoro-d-glucose Uptake by Controlling Environmental Temperature Prior to Positron Emission Tomography Scan

Brown fat uptake of 2-deoxy-2-[F-18]fluoro-D: -glucose (FDG) on a positron emission tomography (PET) scan limits the ability to assess for cancer. Drugs such as benzodiazepine, propranolol, and reserpine have been proposed to reduce this uptake, but the studies have been either small clinical or preclinical trials. As an alternative, we evaluated the effect of controlling the patient's environmental temperature on brown fat uptake of FDG.

METHOD

From January 1, 2002 to November 30, 2004, patients were identified who had (1) a pattern of FDG uptake in the neck/paravertebral areas suggestive of brown fat, (2) a repeat FDG-PET scan after control of the patient's environmental temperature, and (3) no evidence of cancer in the neck/paravertebral areas by other diagnostic methods. For the follow-up PET scan, all patients wore warm clothing and avoided exposure to cold air during their transit to our facility. After arrival, patients were kept in a separate temperature-controlled room (at least 75 degrees F) for 15 minutes to two hours before FDG injection as well as during the uptake phase. Four physicians blindly and retrospectively assessed the FDG uptake in the neck and paravertebral regions on all initial and temperature-controlled PET scans by visually grading the radioactivity on a semiquantitative scale (0 = background, 1+ = background but <liver, 2+ = equal to liver, 3+ >liver). The changes in maximal SUVs were determined in the left and right neck region. Data were evaluated using a two-tail t-test.

RESULTS

Ten patients met the above criteria. The median age was 32 years with a range of 11-58 years. In comparing the semiquantitative uptake and the SUVs of FDG in the neck and paravertebral areas on the initial PET scan to the temperature-controlled PET scan, the mean decrease and the standard deviation of the decrease demonstrated a statistically significant decrease in with P values range from <0.02 to <0.001.

CONCLUSION

Controlling the patient's environmental temperature prior to the dosing and during the uptake phase can significantly reduce FDG uptake in brown fat in the neck and paravertebral areas. Further studies are warranted to determine the most effective protocol to control the patient's environmental temperature in order to minimize brown fat uptake.

INDICATIONS FOR NONOPERATIVE MANAGEMENT OF URETEROCELES

PURPOSE

Ureteroceles have traditionally been managed surgically. We report our indications and outcomes of nonoperative management of ureteroceles in a select cohort.

MATERIALS AND METHODS

We identified prospectively for nonoperative management 11 females and 2 males with ureteroceles associated with hydronephrosis or multicystic dysplasia (MCD). Patients presented with either a febrile urinary tract infection (3) or prenatal hydronephrosis (10). All patients were evaluated with renal and bladder ultrasound, voiding cystourethrography and mercaptoacetyltriglycine-3 furosemide renography. Two subgroups were identified, consisting of 10 duplex system upper pole ureteroceles associated with nonobstructed functional systems and 3 ureteroceles associated with a completely nonfunctional single system (2) or duplex (1) kidneys with or without MCD. Median followup was 41 months (range 13 months to 8 years).

RESULTS

Of the 13 patients 9 required no surgical intervention. Of these 9 patients 3 had either a nonfunctional upper pole moiety (1) or MCD (2) that involuted, and 6 had good function of the upper pole segments relative to the lower pole without high grade obstruction on furosemide renography. Mean upper pole relative to lower pole differential function as determined by isotope renogram in these 6 patients was 40.8% (range 28% to 65%) and median drainage half-time was 5.3 minutes (4.5 to 19.3). On sonography, hydronephrosis improved in all 6 cases, with 5 (83%) decreasing to grade 0 (3) or I (2). Of these 6 cases of duplex system ureteroceles 5 had associated ipsilateral lower pole reflux of grade III (2) or IV (3). Reflux resolved in all cases. Surgery was necessary for progressive obstruction 1 patient and for breakthrough urinary tract infection in 3. The mean upper pole differential function in the operative group of 24.3% was lower than that of the nonoperative group. The initial median drainage half-time was 12.5 minutes (range 6.9 to 20). There was no significant difference between the nonoperative and operative groups in regard to hydronephrosis grade, reflux grade or ureterocele size.

CONCLUSIONS

Furosemide renography can identify a select subgroup of patients with ureteroceles who are candidates for nonoperative management. Ureteroceles with nonobstructed duplex systems have better preservation of renal function and a high rate of natural resolution of hydronephrosis and reflux. Ureteroceles associated with MCD or completely nonfunctioning upper pole moieties may never require surgical management.

Benzodiazepine-resistant "brown fat" pattern in positron emission tomography: two case reports of resolution with temperature control

PURPOSE

Supraclavicular uptake of 2-deoxy-2-[18F]fluoro-D-glucose (FDG) on positron emission tomography (PET) scan is attributed to lymph node, muscle, or brown fat activity. Differentiation between physiological or pathological etiologies is necessary. Benzodiazepine premedication to reduce physiological uptake has been attempted with variable success. A relationship between brown-fat FDG uptake and cold temperature has also been established. To our knowledge, no case reports or studies have been published to demonstrate whether controlling the temperature can alter the physiological uptake in these regions.

PROCEDURES

Two teenage female patients with these patterns on PET scans performed with oral benzodiazepine administration underwent repeat imaging with temperature-controlled environment settings.

RESULTS

Resolution of supraclavicular FDG uptake with temperature control in two patients in whom benzodiazepine had no prior effect.

CONCLUSION

Although the exact mechanism remains unknown, we propose that the control of temperature reduces the metabolism of glucose by brown fat. Further studies are warranted to confirm the above observations, and, if confirmed, to determine the most efficient and effective use of temperature control to minimize supraclavicular and axillary FDG uptake.

Postural headache in a child with Marfan syndrome: case report and review of the literature

The case of a 10-year-old female with Marfan syndrome and postural headache secondary to spontaneous intracranial hypotension is described. The patient was found to have multiple dural ectasias and a cerebrospinal fluid leak at the left cervicothoracic junction. Her presentation, diagnostic work-up, and management are reviewed, and the relevant literature is discussed. Spontaneous intracranial hypotension secondary to cerebrospinal fluid leaks from dural ectasia should be recognized as a potential complication in children with Marfan syndrome and other connective tissue diseases.

Use of furosemide and hearing loss in neonatal intensive care survivors

Hearing loss is a significant morbidity in survivors of the neonatal intensive care unit (NICU). The overall prevalence of hearing loss in neonates is 0.93 per 1000 live births, whereas in neonates weighing less than 2000 g, it is as high as 15.5 per 1000 live births. The increased incidence of hearing loss in NICU graduates has been attributed to their underlying disease process as well as exposure to ototoxic drugs including furosemide. A retrospective chart review of all neonatal intensive care survivors was done to evaluate the potential effect of furosemide on hearing loss. From July 2000 to January 2002, there were 57 neonates who received and 207 neonates who did not receive furosemide. The incidence of abnormal hearing screen was 15.5% in the furosemide group and 15.9% in the nonfurosemide group ( p = 0.9). Although the incidence of hearing loss is significantly higher in NICU graduates in comparison with the general neonatal population, it does not seem to be directly related to the use of furosemide.

Incidence of New Renal Parenchymal Inflammatory Changes Following Breakthrough Urinary Tract Infection in Patients With Vesicoureteral Reflux Treated With Antibiotic Prophylaxis: Evaluation by 99M Technetium Dimercapto-Succinic Acid Renal Scan

PURPOSE

Breakthrough urinary tract infections (UTI) are considered an indication for surgical intervention in children with vesicoureteral reflux (VUR) with the goal of preventing new or progressive renal scarring. We assessed the incidence of new renal parenchymal inflammatory changes following breakthrough UTI in patients on antibiotic prophylaxis for VUR.

MATERIALS AND METHODS

We prospectively analyzed 38 patients (62 refluxing renal units) with VUR. All patients experienced a culture documented breakthrough UTI (greater than 100,000 cfu/ml) while taking antibiotic prophylaxis. Dimercapto-succinic acid (DMSA) scans were obtained 4 to 6 weeks after UTI to detect new renal inflammatory changes and all scans were reviewed by the same pediatric nuclear medicine specialist (MM). To avoid misinterpretation of preexistent renal scarring for acute inflammation, new pyelonephritis was confirmed by comparison to prior DMSA scan.

RESULTS

Of 38 patients 14 (38%) had preexistent renal scarring but only 1 (7%) manifested new changes on DMSA scan. Of the remaining 24 patients with normal baseline studies 3 (12.5%) had changes after UTI. Overall, only 4 patients (10.5%) manifested new changes on DMSA scan. Three additional patients who did not have a baseline scan for comparison demonstrated unequivocal changes of acute pyelonephritis on DMSA scan, increasing the incidence to 17% (7 of 41). Of the patients 7 (17%) underwent surgical correction of reflux and 34 (83%) were maintained on antibiotic prophylaxis.

CONCLUSIONS

Of patients with VUR who experienced a single breakthrough UTI while on antibiotic prophylaxis, at most only 17% had renal inflammatory changes on acute DMSA scan. Our findings endorse the usefulness of DMSA scan in tailoring management of VUR and breakthrough UTI cases, and lend support to continued nonoperative management for the majority.

Color Doppler sonography and scintigraphy of the testis: a prospective, comparative analysis in children with acute scrotal pain

OBJECTIVE

To compare testicular color Doppler sonography with testicular scintigraphy in differentiating between surgical and nonsurgical conditions of the pediatric testis, and to evaluate the role of testicular color Doppler sonography in the pediatric population.

MATERIALS AND METHODS

Forty-six children (age range, 1 day to 18 years; median age, 11 years) with acute scrotal pain were evaluated with both scintigraphy and color Doppler sonography by two separate groups of radiologists who had no knowledge of the results of the other modality. The final radiologic diagnosis was classified as a surgical condition, nonsurgical condition, or indeterminate and was compared with the patient's surgical diagnosis or clinical diagnosis, which was established by response to treatment and follow-up.

RESULTS

Sonography correctly diagnosed 11 of 14 surgical conditions and 31 of 32 nonsurgical conditions. There was one indeterminate sonogram. There were no false-positive examinations, and there were three false-negative examinations (sensitivity = 78.6% [95% CI, 66.7-90.5%], specificity = 96.9% [95% CI, 94.3-99.5%], accuracy = 91.3%). Color flow was demonstrated in the asymptomatic testis in 34 of 44 boys. Scintigraphy correctly diagnosed 11 of 14 surgical conditions and 29 of 32 nonsurgical conditions. There were two indeterminate scintigrams. There were two false-positive examinations and two false-negative examinations (sensitivity = 78.6% [95% CI, 66.7%-90.5%], specificity = 90.6% [95%CI, 82.2%-99.0%], accuracy = 87.0%).

CONCLUSIONS

Color Doppler sonography and scintigraphy show similar sensitivity for the diagnosis of testicular torsion. A small number of false-negative cases can occur with either modality. The two studies may provide complementary information in indeterminate cases.

The spectrum of heterotopic gastric mucosa in children detected by Tc-99m pertechnetate scintigraphy

Meckel's diverticulum is the most common site of heterotopic gastric mucosa (HGM). Other sites include intestinal duplication and the small bowel proper. Tc-99m pertechnetate abdominal scintigraphy is used commonly to detect HGM. This article describes various scintigraphic patterns of HGM and reviews technical aspects of the procedure, with emphasis on pharmacologic enhancement.

Early diuresis renogram findings predict success following pyeloplasty

PURPOSE

We sought to determine whether drainage across the ureteropelvic junction, as indicated by diuretic renography 3 months after pyeloplasty, is an adequate predictor of surgical success.

MATERIALS AND METHODS

The medical records of 150 children who underwent pyeloplasty from 1986 to 1995 were reviewed. After excluding nonevaluable cases a total of 127 renal units remained for investigation. Preoperatively each renal unit was examined with a standardized (well-tempered) furosemide stimulated renal scan. Postoperatively 60 renal units were evaluated with standardized diuretic renal scans at 3 and 12 months, 33 renal units at 3 months only and 34 renal units at 12 months only. Surgical success was defined by half-time less than 20 minutes on a standardized diuretic renogram.

RESULTS

Of the 33 renal units with a single postoperative study at 3 months 32 (97%) had halftime less than 20 minutes on diuretic renography. The remaining patient in this group with half-time greater than 20 minutes showed 60% improvement in half-time and did not require reoperation. Excluding those without delayed followup, surgical success was obtained in 93 of the 94 (99%) renal units. Among the 60 renal units evaluated with 2 postoperative renal scans success was noted in 48 (80%) and 59 (98%) at 3 and 12 months, respectively. Stenosis did not recur in 48 renal units with half-time less than 20 minutes 3 months after repair. In 1 case that had been treated for postoperative urinoma half-time was greater than 40 minutes at 3 months and repeat pyeloplasty was required.

CONCLUSIONS

Half-time less than 20 minutes 3 months after pyeloplasty predicts surgical success. Most renal units that improve but still have half-times greater than 20 minutes on an early diuretic renogram will demonstrate continued improvement in drainage patterns at 12 months. Those renal units that show no improvement at 3 months may require reoperation and those with half-time less than 20 minutes at 3 months do not require further evaluation.

Early diuresis renogram findings predict success following pyeloplasty

PURPOSE

We sought to determine whether drainage across the ureteropelvic junction, as indicated by diuretic renography 3 months after pyeloplasty, is an adequate predictor of surgical success.

MATERIALS AND METHODS

The medical records of 150 children who underwent pyeloplasty from 1986 to 1995 were reviewed. After excluding nonevaluable cases a total of 127 renal units remained for investigation. Preoperatively each renal unit was examined with a standardized (well-tempered) furosemide stimulated renal scan. Postoperatively 60 renal units were evaluated with standardized diuretic renal scans at 3 and 12 months, 33 renal units at 3 months only and 34 renal units at 12 months only. Surgical success was defined by half-time less than 20 minutes on a standardized diuretic renogram.

RESULTS

Of the 33 renal units with a single postoperative study at 3 months 32 (97%) had halftime less than 20 minutes on diuretic renography. The remaining patient in this group with half-time greater than 20 minutes showed 60% improvement in half-time and did not require reoperation. Excluding those without delayed followup, surgical success was obtained in 93 of the 94 (99%) renal units. Among the 60 renal units evaluated with 2 postoperative renal scans success was noted in 48 (80%) and 59 (98%) at 3 and 12 months, respectively. Stenosis did not recur in 48 renal units with half-time less than 20 minutes 3 months after repair. In 1 case that had been treated for postoperative urinoma half-time was greater than 40 minutes at 3 months and repeat pyeloplasty was required.

CONCLUSIONS

Half-time less than 20 minutes 3 months after pyeloplasty predicts surgical success. Most renal units that improve but still have half-times greater than 20 minutes on an early diuretic renogram will demonstrate continued improvement in drainage patterns at 12 months. Those renal units that show no improvement at 3 months may require reoperation and those with half-time less than 20 minutes at 3 months do not require further evaluation.

(99m)Tc-MDP scintigraphic findings in children with leukemia: value of early and delayed whole-body imaging

The purpose of this study was to reveal the bone scan abnormalities in children with leukemia and to show the value of whole-body scanning in early and delayed phases.

METHODS

From a database of all patients with a diagnosis of leukemia from January 1990 to April 2000, 12 children (9 male, 3 female; mean age, 8.0 y; age range, 4.7--13.2 y) were identified for whom the diagnosis of leukemia was suggested on the basis of bone scans obtained as part of the initial work-up for unexplained skeletal pain. Early and delayed whole-body bone scans and radiographs were reviewed retrospectively. Areas of abnormal uptake on early and delayed phases were categorized into locations: metaphysis--diaphysis--epiphysis (MDE), pelvis, ribs, spine, and others. MDE lesions included abnormalities in the metaphysis extending into the diaphysis for some length: metaphysis/diaphysis, metaphysis only, diaphysis only, epiphysis only, and the entire bone. Pelvic and spine lesions were further characterized as focal or diffuse.

RESULTS

Ten patients had lesions in 2 or more locations on both phases. Two patients had multiple lesions on the early scans but only rib lesions on the delayed scans. Lesions correlated with symptomatic sites in 8 patients on the delayed scans and in 11 patients on the early scans. The most common sites of abnormalities on the delayed scans were metaphyseal/diaphyseal, pelvis (focal), and ribs. The most common locations of lesions on the early scans were metaphyseal/diaphyseal, pelvis (diffuse or focal), and spine. More metaphyseal/diaphyseal lesions were seen on the early scans than on the delayed scans. Diffuse involvement of the pelvis and spine was seen only on the early phase. However, rib lesions were seen more frequently on the delayed scan.

CONCLUSION

Early whole-body imaging in conjunction with delayed whole-body scanning may enhance the diagnostic accuracy of bone scanning in the evaluation of children with skeletal pain of obscure etiology, such as that associated with leukemia.

Acute pyelonephritis: comparison of diagnosis with 99mTc-DMSA, SPECT, spiral CT, MR imaging, and power Doppler US in an experimental pig model

PURPOSE

To compare the sensitivity and specificity of technetium-99m dimercaptosuccinic acid (DMSA) single photon emission computed tomography (SPECT), spiral computed tomography (CT), magnetic resonance (MR) imaging, and power Doppler ultrasonography (US) for the detection and localization of acute pyelonephritis by using histopathologic findings as the standard of reference.

MATERIALS AND METHODS

Bilateral vesicoureteric reflux was surgically created in 35 piglets (70 kidneys). One week later, a liquid bacterial culture of Escherichia coli was injected into the bladder. Three days after induction of urinary infection, imaging studies were performed, and the kidneys were removed for histopathologic examination. SPECT images were obtained 2-3 hours after injection of 99mTc-DMSA. Transverse and coronal MR images were obtained with gadolinium-enhanced fast inversion recovery. Transverse CT images were obtained before and after injection of contrast agent. Power Doppler US was performed in longitudinal, transverse, and coronal planes. Each kidney was divided into three zones for correlation of findings.

RESULTS

Histopathologic examination revealed pyelonephritis in 102 zones in 38 kidneys. Sensitivity and specificity for detecting pyelonephritis in the kidneys were 92.1% and 93.8% for SPECT, 89.5% and 87.5% for MR imaging, 86.8% and 87.5% for CT, and 74.3% and 56.7% for US. Sensitivity and specificity for detecting pyelonephritis in the zones were 94.1% and 95.4% for SPECT, 91.2% and 92.6% for MR imaging, 88.2% and 93.5% for CT, and 56.6% and 81.4% for US. The pairwise comparison of these modalities showed no statistically significant difference among them except for US.

CONCLUSION

99mTc-DMSA SPECT, spiral CT, and MR imaging appear to be equally sensitive and reliable for the detection of acute pyelonephritis; power Doppler US is significantly less accurate.

A cost analysis of two anterior cervical fusion procedures

Multilevel anterior cervical discectomy and fusion (ACDF) remains a difficult problem. A recently described surgical technique for multilevel ACDF has eliminated the morbid complications associated with harvesting iliac crest bone graft (ICBG) while maintaining the advantages of using autologous bone graft. A matched-pairs t test was used to compare the estimated costs of 27 ACDFs using titanium surgical mesh, local autologous bone graft, and anterior plate instrumentation with 27 ACDFs using ICBG and plate fixation. The three variables considered were cage cost, operating time (cost), and hospitalization cost. The estimated costs for the two surgical procedures were not significantly different. Thus, the time saved by not harvesting an ICBG was comparable to the cost of the cage. Harvesting ICBG also increased the morbidity rate by 22%.

Scapulothoracic stabilisation for winging of the scapula using strips of autogenous fascia lata

We have used a modified technique in five patients to correct winging of the scapula caused by injury to the brachial plexus or the long thoracic nerve during transaxillary resection of the first rib. The procedure stabilises the scapulothoracic articulation by using strips of autogenous fascia lata wrapped around the 4th, 6th and 7th ribs at least two, and preferably three, times. The mean age of the patients at the time of operation was 38 years (26 to 47) and the mean follow-up six years and four months (three years and three months to 11 years). Satisfactory stability was achieved in all patients with considerable improvement in shoulder function. There were no complications.

Scapulothoracic stabilisation for winging of the scapula using strips of autogenous fascia lata

We have used a modified technique in five patients to correct winging of the scapula caused by injury to the brachial plexus or the long thoracic nerve during transaxillary resection of the first rib. The procedure stabilises the scapulothoracic articulation by using strips of autogenous fascia lata wrapped around the 4th, 6th and 7th ribs at least two, and preferably three, times.

The mean age of the patients at the time of operation was 38 years (26 to 47) and the mean follow-up six years and four months (three years and three months to 11 years). Satisfactory stability was achieved in all patients with considerable improvement in shoulder function. There were no complications.

Adjunctive oral corticosteroids reduce renal scarring: the piglet model of reflux and acute experimental pyelonephritis

PURPOSE

We investigate the efficacy of antibiotics combined with corticosteroid in diminishing post-pyelonephritic renal scarring compared to standard antibiotic therapy.

MATERIALS AND METHODS

Bilateral vesicoureteral reflux was surgically created in 36 piglets (72 kidneys). A week later each bladder was inoculated by percutaneous injection with a standardized broth culture of Escherichia coli and molten paraffin. 99mTechnetium dimercapto-succinic acid (DMSA) scintigraphy was performed 3 days after introduction of urinary infection to detect the presence of acute pyelonephritis. Acute pyelonephritic lesions seen on DMSA scans were graded according to the percentage of renal zone involvement as grade 1--less than 33%, grade 2--33 to 66% and grade 3--greater than 66% involved. When pyelonephritis was present, piglets were randomized to receive either standard antibiotics or antibiotics and 2 mg./kg. prednisolone daily. 99mTechnetium-DMSA scintigraphy was repeated 2 months after completion of therapy, and the kidneys were harvested for gross and histopathological examination. Each kidney was divided into upper, middle and lower zones for correlation of pathological and imaging findings. Severity of renal scarring was then assessed using histopathological confirmation of gross anatomical findings as grade 1--less than 1, grade 2-1 to 2 and grade 3-greater than 2 cm.

RESULTS

Acute pyelonephritis was induced in 136 of 216 renal zones. The sites of renal scarring corresponded anatomically to sites of acute pyelonephritis in all but 5 cases. Overall, the prevalence of post-pyelonephritic scarring was 56.6% (77 of 136) of renal zones. The severity of scarring in both groups correlated with the severity of the initial pyelonephritic lesion. Of the 31 zones that formed grade 3 renal scars the distribution of grades 1, 2 and 3 acute pyelonephritis on the initial DMSA scan was 3, 26 and 71%, respectively. Grade 3 acute pyelonephritis was more likely to result in severe (grade 3) renal scars in the control compared to the steroid treated group (59 versus 31%). Overall, acute pyelonephritis completely resolved in 40% of controls and 51% of steroid treated animals. However, only 9% of control animals with grade 3 acute pyelonephritis demonstrated complete resolution, as opposed to 28% of those receiving steroids.

CONCLUSIONS

The risk of renal scarring is greatest after severe acute pyelonephritis involving greater than 66% of a renal zone. Adjunctive oral prednisolone appears to be effective in diminishing renal scarring in severely affected kidneys. In kidneys with mild and moderate acute pyelonephritis antibiotics alone appear to be equally effective in preventing scarring.

The role of 99mtechnetium dimercapto-succinic acid renal scans in the evaluation of occult ectopic ureters in girls with paradoxical incontinence

PURPOSE

We describe the use of 99mtechnetium (Tc) dimercapto-succinic acid (DMSA) renal scintigraphy to document poorly functioning and/or ectopic renal units associated with occult ectopic ureters.

MATERIALS AND METHODS

During the last 8 years 6 toilet-trained girls were referred for lifelong continuous urinary dribbling. Initial radiological evaluation included renal and bladder sonography in 6, excretory urography in 4, a mercaptoacetyltriglycine-3 renal scan in 1 and cystovaginoscopy in 2. Ultimately a 99mTc-DMSA renal scan was performed in all 6 girls before surgical intervention.

RESULTS

Sonography failed to establish the diagnosis of ureteral ectopia in all cases, and revealed a normal solitary kidney in 3, normal kidneys in 1, an apparently uncomplicated unilateral duplication without hydroureteronephrosis in 1 and a contralateral uncomplicated duplication in 1. Excretory urography in 4 cases was inconclusive and showed a solitary kidney in 1, ipsilateral duplication without a normal appearing upper pole collecting system in 1, contralateral uncomplicated duplication in 1 and normal kidneys in 1. A mercaptoacetyltriglycine-3 renal scan in another girl with a solitary kidney on sonography failed to demonstrate a contralateral small ectopic kidney. Cystovaginoscopy performed in 2 patients by other pediatric urologists was nondiagnostic. 99mTc-DMSA renal scintigraphy was diagnostic in all 6 cases, and revealed a small poorly functioning ectopic kidney in 3 and a poorly functioning dysplastic upper pole moiety in 3, which were consistent with a diagnosis of ureteral ectopia. An ectopic ureter was confirmed by cystoscopic and surgical findings in all girls.

CONCLUSIONS

99mTc-DMSA renal scintigraphy reliably detects and localizes hypoplastic ectopic kidneys and poorly functioning upper pole moieties associated with occult ectopic ureters in girls with continuous urinary leakage.

Oral versus initial intravenous therapy for urinary tract infections in young febrile children

BACKGROUND

The standard recommendation for treatment of young, febrile children with urinary tract infection has been hospitalization for intravenous antimicrobials. The availability of potent, oral, third-generation cephalosporins as well as interest in cost containment and avoidance of nosocomial risks prompted evaluation of the safety and efficacy of outpatient therapy.

METHODS

In a multicenter, randomized clinical trial, we evaluated the efficacy of oral versus initial intravenous therapy in 306 children 1 to 24 months old with fever and urinary tract infection, in terms of short-term clinical outcomes (sterilization of the urine and defervescence) and long-term morbidity (incidence of reinfection and incidence and extent of renal scarring documented at 6 months by 99mTc-dimercaptosuccinic acid renal scans). Children received either oral cefixime for 14 days (double dose on day 1) or initial intravenous cefotaxime for 3 days followed by oral cefixime for 11 days.

RESULTS

Treatment groups were comparable regarding demographic, clinical, and laboratory characteristics. Bacteremia was present in 3.4% of children treated orally and 5.3% of children treated intravenously. Of the short-term outcomes, 1) repeat urine cultures were sterile within 24 hours in all children, and 2) mean time to defervescence was 25 and 24 hours for children treated orally and intravenously, respectively. Of the long-term outcomes, 1) symptomatic reinfections occurred in 4.6% of children treated orally and 7.2% of children treated intravenously, 2) renal scarring at 6 months was noted in 9.8% children treated orally versus 7.2% of children treated intravenously, and 3) mean extent of scarring was approximately 8% in both treatment groups. Mean costs were at least twofold higher for children treated intravenously ($3577 vs $1473) compared with those treated orally.

CONCLUSIONS

Oral cefixime can be recommended as a safe and effective treatment for children with fever and urinary tract infection. Use of cefixime will result in substantial reductions of health care expenditures.

Consensus on renal cortical scintigraphy in children with urinary tract infection. Scientific Committee of Radionuclides in Nephrourology

A questionnaire related to cortical scintigraphy in children with urinary tract infection was submitted to 30 experts. A wide consensus was reached on several issues related to planar images: 99mTc dimercapto succinic acid (DMSA) appears as the most appropriate tracer for renal imaging; dynamic tracers are considered to be inferior, in particular 99mTc diethylenetriaminepentaacetate, which is not recommended. The general opinion is that DMSA scintigraphy is not feasible with a minimal dose below 15 MBq, whereas the maximum dose should not be higher than 110 MBq. The dose schedule generally is based on body surface area, and sedation is only exceptionally given to children. Images are obtained 2 to 3 hours after injection, preferably with high resolution collimators; pinhole images are used by only half of the experts. Posterior and posterior oblique views are used by most of the experts, and the posterior view is acquired in supine positions. At least 200.000 kcounts or 5 minute acquisition is required for nonzoomed images. As a quality control, experts check the presence of blurred or double outlines on the DMSA images. Color images are not used and experts report on film or directly on the computer screen. As far as normal DMSA images are concerned, most experts agree on several normal variants. Hydronephrosis is not a contraindication for DMSA scintigraphy but constitutes a pitfall. Differential renal function generally is measured, but no consensus is reached whether or not background should be subtracted. Most of the experts consider 45% as the lowest normal value. A consensus is reached on some scintigraphic aspects that are likely to improve and on some others that probably represent persistent sequelae. There is a wide consensus for the systematic use of DMSA scintigraphy for detection of renal sequelae, whereas only 58% of the experts are systematically performing this examination during the acute phase of infection.

Imaging in pediatric urology

A multitude of disorders of the genitourinary tract can occur in children. Although some entities may be diagnosed clinically, radiologic imaging is often necessary for diagnosis and management. The radiologic work-up has been discussed using a problem-oriented approach in five clinical situations: urinary tract infection, hydronephrosis or hydroureter, trauma, swollen scrotum, and hematuria. This discussion provides some general guidelines, although the evaluation of each child may need to be individualized depending on their specific clinical symptomatology.

In-111 pentetreotide scintigraphy in patients with neuroblastoma. Comparison with I-131 MIBG, N-Myc oncogene amplification, and patient outcome

OBJECTIVE

1. To evaluate the relative efficacy of In-111 pentetreotide and 1-131 radioiodinated meta-idobenzyl guanidine (MIBG) for detection of primary and metastatic neuroblastoma. 2. To assess the prognostic value of In-111 pentetreotide uptake.

METHODS AND MATERIALS

Seven In-111 pentetreotide and seven I-131 MIBG scans were obtained in six patients with stage IV neuroblastoma and 1 with stage III ganglioneuroblastoma. Three scans were obtained at initial staging and four were obtained during therapy. Correlation was made with concomitant computed tomography scans, bone scans, N-myc oncogene amplification, and clinical outcome.

RESULTS

Primary tumor was present in six patients and had been resected in 1. In-111 pentetreotide uptake was seen in two of six primary tumors, I-131 MIBG scan was positive in five of six. In-111 pentetreotide scan was positive in two of four patients with bone metastases, I-131 MIBG scan was positive in three of four. Both showed liver metastases in one patient and did not show bone marrow metastases in another. Overall sensitivity for primary or metastatic disease was 57% (four of seven) for In-111 pentetreotide and 86% (six of seven) for MIBG. Correlation between N-myc oncogene and In-111 pentetreotide uptake was seen in four of seven patients. In-111 pentetreotide uptake correlated with the clinical outcome in six patients with more than 1 year follow-up. Two patients with negative In-111 pentetreotide scans had unfavorable outcome. One patient died, and the other had local recurrence 15 months after diagnosis. Four patients with a positive scan are alive without disease on follow-up at 13-31 months after diagnosis.

CONCLUSION

In-111 pentetreotide scintigraphy is less sensitive than I-131 MIBG for detecting active neuroblastoma. In-111 pentetreotide uptake on scintigraphy may correlate with the prognosis. However, a larger series of patients is needed for further evaluation.

Technetium-99m-DMSA renal cortical scintigraphy to detect experimental acute pyelonephritis in piglets: comparison of planar (pinhole) and SPECT imaging

The purpose of this study was to directly compare the sensitivity and specificity of SPECT and pinhole imaging for the detection of acute pyelonephritis using histology as the standard of reference.

METHODS

Bilateral vesicoureteral reflux of infected urine was induced in 16 piglets (32 kidneys) by unroofing the intravesical ureter and subsequently instilling a broth culture of E. coli into the bladder. DMSA scans were obtained by both pinhole and SPECT techniques at 24 hr (4 piglets), 48 hr (5 piglets), 72 hr (4 piglets) and 10 days (3 piglets) after instillation of bacteria into the bladder. Kidneys were harvested immediately after scintigraphy for histopathologic examination. Results of the SPECT images, pinhole images and histologic findings were interpreted independently in a blinded fashion. The images of each kidney were classified as positive or negative for pyelonephritis regardless of the severity and number of lesions. To evaluate accuracy of SPECT and pinhole imaging for the detection of individual lesions, each kidney was arbitrarily divided into three zones (upper, middle and lower). Image findings were then compared with the pathology results for the presence or absence of pyelonephritis in each zone.

RESULTS

Histopathology revealed pyelonephritis in 24 of 32 kidneys (58 of 96 zones). The sensitivity of the DMSA scan for detection of affected kidneys was 92% for SPECT and 83% for pinhole; overall accuracy was 88% for both. The sensitivity of SPECT for the detection of affected renal zones was slightly better than pinhole imaging (91% compared with 86%), but its specificity was lower (82% compared with 95%) resulting in a similar accuracy. Excluding four piglets where scans were obtained within 24 hr after instillation of bacteria into the bladder, the sensitivity of SPECT and pinhole for the detection of affected kidneys were 95% and 90%, respectively. Their overall accuracy were 96% and 92%. In this subgroup, the sensitivity, specificity and accuracy of SPECT for the detection of involved zones were 96%, 95% and 96%, respectively. The corresponding values for pinhole imaging were 90%, 95% and 92%, respectively.

CONCLUSION

Although the sensitivity of SPECT for the detection of acute pyelonephritis is slightly better than pinhole DMSA scan, the overall accuracy of these two imaging techniques is essentially the same.

The role of 131 iodine-metaiodobenzylguanidine scanning in the correlative imaging of patients with neuroblastoma

OBJECTIVE

Metaiodobenzylguanidine (MIBG) scans were studied to determine the impact of the scan results on the clinical treatment of pediatric patients with neural crest tumors.

METHODS

Serial scans were reviewed retrospectively for 27 patients with neural crest tumors: 25 with initial diagnoses of neuroblastoma (NB), 1 with ganglioneuroblastoma, and 1 with ganglioneuroma (GN). Results were compared with bone scans and computed tomography scans, as well as surgical pathologic findings.

RESULTS

At initial diagnosis, when compared with bone and computed tomographic scans, MIBG imaging did not identify any unsuspected lesions that resulted in a change in staging. Thirteen patients with NB who had initially positive MIBG scan results had serial studies that normalized during therapy. However, after completion of therapy, 8 of 13 had relapses of the disease. Although areas of active disease were well delineated by other standard imaging modalities for all 8, only 4 (50%) had MIBG study results that were positive in sites of relapse. There were 4 cases of GN (1 at diagnosis and 3 after therapy for NB) demonstrating an uptake of MIBG that was similar in appearance to that in NB.

CONCLUSIONS

MIBG imaging did not change the staging or alter treatment during therapy for any patient. Normalization of positive study results was an unreliable indicator of outcome for children with NB. Furthermore, when relapse occurred, MIBG scans identified only 50% of those with active NB. The uptake of MIBG in GN was indistinguishable from that in NB. In this series, the results of serial MIBG studies did not have a significant impact on patient treatment.

Outcome analysis of pediatric pyeloplasty as a function of patient age, presentation and differential renal function

PURPOSE

We retrospectively reviewed a consecutive series of patients who underwent pyeloplasty. In all cases preoperative and postoperative isotope renal scans were performed to assess the surgical outcome with particular emphasis on the change in renal function postoperatively.

MATERIALS AND METHODS

The clinical records of 108 consecutive children with ureteropelvic junction obstruction were reviewed. Individual renal function was evaluated and obstruction was confirmed by diuretic assisted 99mtechnetium diethylenetriaminepentaacetic acid or mercaptoacetyltriglycine renography. A total of 100 pyeloplasties in 98 children between 5 days and 16 years old was included. Results were analyzed by groups according to patient age and symptoms at presentation.

RESULTS

Drainage half-times improved in 98% of patients and only 1 required reoperation. Improved renal function greater than 5% was noted in about a third of each age group. Function remained stable in 68% of the kidneys and decreased in only 1. Of the improved kidneys 77% had impaired function preoperatively (40% or less of the total contribution). Those presenting with a renal mass had the greatest improvement in function. There was no statistically significant difference in improvement in renal function by age group or patient presentation. Regression analysis revealed that preoperative differential renal function was the only statistically significant predictor of improvement in renal function after pyeloplasty.

CONCLUSIONS

Pyeloplasty in children is safe and renal functional improvement can be expected in the majority of kidneys with impaired function at presentation. However, there was no indication that early pyeloplasty in infants is more likely to result in improved function than in older children.