Radiographic evaluation of children with febrile urinary tract infection: bottom-up, top-down, or none of the above?

SNMMI procedure standard/EANM practice guideline on pediatric [99mTc]Tc-DMSA renal cortical scintigraphy: an update

The Society of Nuclear Medicine and Molecular Imaging (SNMMI), founded in 1954, is an international scientific and professional organization with a purpose to promote the science, technology, and practical application of nuclear medicine. The European Association of Nuclear Medicine (EANM), founded in 1985, is a nonprofit professional medical association with a purpose to facilitate international communication among individuals in nuclear medicine pursuing clinical and academic excellence. Members of the SNMMI and EANM are physicians, technologists, and scientists who specialize in the research and practice of nuclear medicine. The SNMMI and EANM will periodically publish new guidelines for nuclear medicine practice to further advance the science of nuclear medicine and improve patient care. Existing standards/guidelines will be reviewed for revision or renewal, as appropriate. Each standard/guideline, representing a policy statement by the SNMMI/EANM, has undergone a thorough review, and represents an expert consensus. The SNMMI and EANM recognize that the safe and effective use of diagnostic nuclear medicine imaging requires specific training and skills, as described in each document. These standards/guidelines are educational resources designed to assist practitioners in providing appropriate nuclear medicine care for patients. They are consensus documents, and are not mandatory provisions or requirements of practice. They are not intended, nor should they be used, to establish a legal standard of care. For these reasons and those set forth below, the SNMMI and the EANM cautions against the use of these standards/guidelines in litigation procedures that call into question the clinical decisions of a practitioner. The ultimate judgment regarding the appropriateness and propriety of any specific procedure or course of action must be made by medical professionals, taking into account the unique context of each case. Thus, there is no implication that action differing from what is detailed in these standards/guidelines, on its own, is below the standard of care. On the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set forth in the standards/guidelines when, based on the reasonable judgment of the practitioner, such course of action is warranted based on the condition of the patient, limitations of available resources, or advances in knowledge or technology subsequent to publication of the standards/guidelines. Practicing medicine involves not only the science, but also the art of dealing with the prevention, detection, diagnosis, and treatment of disease. The variety and complexity of human conditions make it impossible for general guidelines to consistently allow for an accurate diagnosis to be reached or a specific treatment response to be predicted. Therefore, it should be recognized that adhering to these standards/guidelines does not ensure a successful outcome. All that should be expected is that a practitioner follows a reasonable course of action based on their level of training, the current landscape of knowledge, the resources at their disposal, and the needs/context of the particular patient being treated. The purpose of this document is to provide nuclear medicine physicians, radiologists, and other clinicians with guidelines for the recommendation, performance and interpretation of 99mTc-dimercaptosuccinic acid renal cortical scintigraphy ([99mTc] Tc-DMSA scintigraphy) in pediatric patients. These recommendations represent the expert opinions of experienced leaders in this field, and these recommendations are not all supported by a high level of evidence. Further studies are required to have evidence-based recommendations for the application of [99mTc] Tc-DMSA renal cortical scintigraphy in pediatrics. This guideline summarizes the views of the SNMMI Renal Cortical Scintigraphy in Children Working Group and the EANM Pediatrics Committee. It reflects recommendations for which the SNMMI and EANM cannot be held responsible. The recommendations should be taken into context of good practice of nuclear medicine and do not substitute for national and international legal or regulatory provisions.

Contrast-enhanced voiding urosonography in the assessment of vesical-ureteral reflux: the time has come

Vesicoureteral reflux (VUR) is a pathological condition contradistinguished by monolateral or bilateral retrograde flow of urine from the bladder to the ureter and to the kidney. If not properly recognized and treated, VUR can potentially be associated to several complications such as recurrent infections and possible secondary scars with Chronic Kidney Disease (CKD). Furthermore, it represents an important risk factor for nephrovascular hypertension. During the last 20 years, the diagnostic approach to this entity has passed through several, drastic changes: indeed, since its introduction in 1994 contrast-enhanced voiding urosonography (ceVUS) has gradually accompanied the voiding cystourethrography (VCUG) as alternative imaging technique for the diagnosis and staging of VUR. Despite a large number of papers has strongly encouraged its use in clinical practice, due to the lack of ionizing radiations and its high sensitivity rate, to date almost all the guidelines only include the VCUG for VUR diagnosis. The introduction of technologically advanced US software and the approval of the intravesical administration of ultrasound contrast agents by the Food and Drug Administration (FDA) and by the European Medicine Agency (EMA) have to induce the Scientific Community to a deep revaluation of the role of ceVUS in the diagnosis and follow-up of VUR: urosonography might extensively replace VCUG as the reference method, reserving to cystourethrography a role in the most complex anatomic settings for pre-surgical evaluation.

Targeted Indication of Imaging for Detection of Vesicoureteric Reflux after Pediatric Febrile Urinary Tract Infections Based on a Multiparametric Computational Tool

OBJECTIVES

Diagnostic workup after febrile urinary tract infections (fUTIs) in children remains a matter of debate. The authors aimed to evaluate multiple parameters in order to design a predictive tool enabling a targeted indication of voiding cystourethrography (VCUG).

METHODS

Records of 383 consecutive children who underwent a VCUG as well as a dimercaptosuccinic-acid (DMSA) scan after febrile urinary tract infections (fUTIs) at a single institution between 04/2009 and 06/2014 were reviewed. Twenty parameters were recorded. After regression analysis, 6 parameters were incorporated into a computational tool aiming at a targeted indication of an eventual VCUG. The performance of the tool was prospectively tested on 100 patients.

RESULTS

Postpyelonephritic alterations on DMSA, duplex systems, age 1-3 y, duration of fever >3 d, >2 fUTIs before VCUG and abnormal sonography findings were identified as significant predictors (p < 0.05 each); the presence of bladder and bowel dysfunction (BBD) was negatively associated with vesicoureteric reflux (VUR). The resulting computational tool achieved an Area under the curve (AUC) of 0.686 (CI 0.633-0.740). Prospective evaluation (100 new patients) revealed a sensitivity of 85.1%, a specificity of 49.1%, a positive predictive value of 59.7% and a negative predictive value of 78.7%.

CONCLUSIONS

The differentiated indication of a VCUG based on the use of a tool was efficient in optimizing the specificity of the diagnostic algorithm after fUTIs. The tool outperformed other common clinical approaches in terms of VUR detection and VCUG frequency. After validation and further refinement in a multicentric approach, this strategy could significantly enhance VUR detection whilst reducing the number of VCUGs.

Delayed diagnosis of primary vesicoureteral reflux in children with recurrent urinary tract infections: Diagnostic approach and renal outcomes

OBJECTIVE

In this study, we aimed to assess renal outcomes of delayed diagnosis of dilating primary vesicoureteral reflux (VUR) following recurrent febrile urinary tract infections (fUTIs) and its diagnostic imaging procedures.

MATERIAL AND METHODS

The medical records of patients who underwent ultrasonography (US), non- acute dimercaptosuccinic acid (Tc-99mDMSA) scintigraphy and voiding cystourethrography (VCUG), and who were older than 2 years at the time of VUR diagnosis were retrospectively reviewed.

RESULTS

A total of 32 children (female, n=27: 84.4%) with a mean age of 7.67±3.34 years at the time of diagnosis of VUR were included in the study. Grade III, IV, V VUR were found in 22%, 69%, and 9% of the patients, respectively. At the time of VUR diagnosis, abnormal US findings were detected in 75% of the cases. Tc-99mDMSA detected abnormalities in 83.9% (7 with a single scar, 7 with multiple lesions, 12 with reduced kidney function) of the patients. Estimated glomerular filtration rate of 3 patients with bilateral grade IV VUR was <75 mL/min/1.73 m². In 5 patients (16%), VUR could not be predicted by US+DMSA scintigraphy (Grade IV VUR in 3 and Grade III in 2 cases ). The sensitivity in predicting VUR was 75.00% (95% CI: 56.60-88.54) and 83.87% (95% CI: 66.27-94.55), respectively, for US alone and combined US+DMSA.

CONCLUSION

VCUG should be performed routinely in addition to US and non-acute DMSA in all children referred with recurrent fUTIs. Awareness of childhood UTI in public and healthcare personnels should be increased in order to refer these patients at a early stage to pediatric urology and nephrology units.

Comparison of contrast-enhanced voiding urosonography with voiding cystourethrography in pediatric vesicoureteral reflux

OBJECTIVE

Voiding cystourethrography (VCUG) has been considered as the gold standard technique for the diagnosis of vesicoureteral reflux (VUR). But, it requires fluoroscopic guidance which expose children to radiation. Voiding urosonography (VUS) is technically analogous to VCUG and has the major advantage of zero radiation exposure. This study aims to determine the efficacy of contrast enhanced-VUS (ce-VUS) with respect to VCUG in diagnosing VUR.

MATERIAL AND METHODS

This study involves 30 children over a period of 3 years. All patients underwent a VCUG followed by the ce-VUS on the same day. All VUS studies were done by the same sonologist in the sonography department. The images were recorded and reviewed by the same sonologist before reporting.

RESULTS

The median age of the patients was 51.53 months. There were 21 males and 9 females. On VCUG, 16 patients had no reflux, and 14 patients had reflux. On ce-VUS, 14 patients had no VUR, and 16 patients had VUR. Of the total 58 kidney-ureter units (KUUs), VUR was detected in 17 KUUs on VCUG and in 21 KUUs on ce-VUS. Thus, ce-VUS detected 4 refluxing units that were not seen on VCUG. In right KUUs, ce-VUS detected VUR in 3 units where no reflux was found in VCUG. In the 28 left KUUs, 25 units on ce-VUS showed concordance with the grade of VUR as detected by VCUG; 3 were discordant. Two units on ce-VUS showed a VUR one grade higher than the corresponding grade on VCUG and in one unit it was one grade lower. Thus, in total, ce-VUS picked up 4 cases which were missed by VCUG.

CONCLUSION

ce-VUS is a good imaging modality when compared to voiding cystourethrography to assess pediatric vesicoureteral reflux, in view of its superior diagnostic performance, feasibility and radiation safety for children.

Urinary C-megalin for screening of renal scarring in children after febrile urinary tract infection

BackgroundFebrile urinary tract infection (fUTI) in children may cause renal scarring. This study aimed to investigate the usefulness of urinary biomarkers for diagnosing renal scarring after fUTI.MethodsThirty-seven children (median age: 1.36 years, range: 0.52-12.17 years, 25 boys) with a history of fUTI, who underwent renal scintigraphy for 4 months or longer after the last episode of fUTI, were analyzed. A spot urine sample was obtained on the day of renal scintigraphy to measure levels of total protein, N-acetyl-β-D-glucosaminidase (NAG), β₂-microglobulin (BMG), neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid binding protein (L-FABP), and C-megalin (full-length megalin). Results were corrected for urinary creatinine (Cr) and compared between the group with renal scarring (n=23) and that without scarring (n=14). Urinary levels of C-megalin were also measured in healthy control subjects.ResultsNo significant differences in total protein, NGAL, L-FABP, NAG, and BMG levels were found between the groups. However, C-megalin levels were significantly higher in the renal scarring group than in the non-renal scarring group and healthy controls (P<0.001). A cutoff value of 6.5 pmol/nmol of urinary C-megalin/Cr yielded 73.9% of specificity and 92.9% of sensitivity.ConclusionUrinary C-megalin is useful for diagnosing renal scarring caused by fUTI.

Elucidation of Renal Scars in Children With Vesicoureteral Reflux Using Contrast-Enhanced Ultrasound: A Pilot Study

Introduction

Vesicoureteral reflux is a common disorder in children but can result in kidney scarring following acute pyelonephritis. The gold standard diagnostic to detect renal scars in children is ^99mTc-dimercaptosuccinic acid (DMSA) scintigraphy. DMSA has a number of limitations including radiation exposure, need for sedation, and radiotracer supply shortages. Contrast-enhanced ultrasound (CEUS) is a technique whereby biocompatible microspheres of inert gas are administered i.v. that reflect ultrasonography sound waves and do not involve radiation. Because the contrast agent is rapidly cleared, contrast images must be obtained within minutes of administration. CEUS has been used in a variety of organ systems, but its use in pediatric kidney diseases is limited.

Methods

In this study, we performed CEUS in 7 children with documented renal scars by radiographic imaging consistent with reflux nephropathy.

Results

In all subjects, CEUS detected all previously known radiologic abnormalities as well as detecting new areas of hypoenhancing renal parenchyma. None of the patients experienced any serious adverse events.

Discussion

This study represents the first report of using CEUS to characterize renal scars in children with reflux nephropathy. We conclude that CEUS is a highly sensitive, rapid, and cost-effective diagnostic imaging modality for detecting and monitoring renal scars in children with vesicoureteral reflux.

Paediatric Urinary Tract Infection: A Hospital Based Experience

INTRODUCTION

Paediatric Urinary Tract Infection (UTI) is one of the commonly encountered entities by paediatricians. Studies have shown easy vulnerability of paediatric urinary tract in any acute febrile illness and a miss in diagnosis could have long term consequences like renal scaring with its adverse effects. Bearing these evidence based preludes in view we designed our study to know the prevalence of UTI in Kashmir province.

AIM

Aim of the present study was to know the prevalence of UTI in febrile children and to know the sensitivity of different imaging modalities like Renal and Urinary Bladder Ultrasonography (RUS), Voiding Cystourethrography (VCUG) and Dimercaptosuccinic Acid (DMSA) scan in diagnosing UTI.

MATERIALS AND METHODS

A total of 304 patients, between 2 months to 10 years, with axillary temperature of ≥ 100.4^oF (38^oC), who did not have a definite source for their fever and who were not on antibiotics were included in the study. Detailed history and through clinical examination was done to rule out any potential or definite focus of infection as per the predesigned proforma. Routine urine examination with culture and sensitivity, followed by RUS and VCUG was done in all patients where routine urine examination was suggestive of UTI. DMSA was done in only culture proven cases after 6 months to document the renal scarring.

RESULTS

Out of 304 children, 140 were males and 164 were females, UTI was present in 40 patients who had fever without any apparent cause giving a prevalence of 13.2%. Escherichia coli (E. coli) were the commonest isolated organism, followed by Klebsiella and Citrobacter species. Renal and Urinary Bladder Ultrasonography (RUS) detected Vesicoureteral Reflux (VUR) in 25% (10/40) while VCUG showed VUR in 55% (22/40) giving a RUS sensitivity of 45% for detecting VUR. DMSA done only after 6 months in UTI diagnosed patients showed a renal scarring in 25% (10/40) patients.

CONCLUSION

Missing a febrile paediatric UTI, can prove a future catastrophe if not timely diagnosed and treated.

The role of voiding cystourethrography in the investigation of children with urinary tract infections

Urinary tract infections (UTIs) represent a common bacterial cause of febrile illness in children. Of children presenting with a febrile UTI, 25-40% are found to have vesicoureteral reflux (VUR). Historically, the concern regarding VUR was that it could lead to recurrent pyelonephritis, renal scarring, hypertension, and chronic kidney disease. As a result, many children underwent invasive surgical procedures to correct VUR. We now know that many cases of VUR are low-grade and have a high rate of spontaneous resolution. The roles of surveillance, antibiotic prophylaxis, endoscopic injection, and ureteral reimplantation surgery also continue to evolve. In turn, these factors have influenced the investigation of febrile UTIs. Voiding cystourethrography (VCUG) is the radiographic test of choice to diagnose VUR. Due to its invasive nature and questionable benefit in many cases, the American Academy of Pediatrics (AAP) no longer recommends VCUG routinely after an initial febrile UTI. Nevertheless, these guidelines pre-date the landmark Randomized Intervention of Children with Vesicoureteral Reflux (RIVUR) trial and there continues to be controversy regarding the diagnosis and management of VUR. This paper discusses the current literature regarding radiographic testing in children with febrile UTIs and presents a practical risk-based approach for deciding when to obtain a VCUG.

Renal Ultrasound for Infants Younger Than 2 Months With a Febrile Urinary Tract Infection

OBJECTIVE

The purpose of this study is to determine the performance of renal ultrasound for detecting vesicoureteral reflux (VUR) and obstructive uropathies in infants younger than 2 months with a febrile urinary tract infection (UTI).

MATERIALS AND METHODS

We performed a retrospective cohort study of infants younger than 2 months with fever and culture-proven UTI presenting from July 1, 2008, through December 31, 2011, with renal ultrasound and voiding cystourethrogram (VCUG) performed within 30 days of UTI diagnosis. Two pediatric radiologists independently reviewed the renal ultrasound and VCUG findings. Results of the renal ultrasound were deemed abnormal if collecting system dilation, renal size asymmetry, collecting system duplication, urothelial thickening, ureteral dilation, or bladder anomalies were present. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of renal ultrasound were calculated using VCUG as reference standard.

RESULTS

Of the 197 patients included (mean [SD] age, 33 [ 15 ] days; male-to-female ratio, 2:1), 25% (n = 49) had VUR grades I-V, with 16% (n = 31) having VUR grades III-V and 8% (n = 15) having VUR grades IV-V. For grades I-V VUR, sensitivity was 32.7% (95% CI, 20.0-47.5%), specificity was 69.6% (95% CI, 61.5-76.9%), PPV was 26.2% (95% CI, 15.8-39.1%), and NPV was 75.7% (95% CI, 67.6-82.7%). For grades III-V VUR, sensitivity was 51.6% (95% CI, 33.1-69.9%), specificity was 72.9% (95% CI, 65.5-79.5%), PPV was 26.2% (95% CI, 15.8-39.1%), and NPV was 89.0% (95% CI, 82.5-93.7%). For grades IV-V VUR, sensitivity was 86.7% (95% CI, 59.5-98.3%), specificity was 73.6% (95% CI, 66.6-79.9%), PPV was 21.3% (95% CI, 11.9-33.7%), and NPV was 98.5% (95% CI, 94.8-99.8%). No obstructive uropathies were diagnosed by VCUG in patients with normal renal ultrasound findings.

CONCLUSION

In infants younger than 2 months, a normal renal ultrasound makes the presence of grades IV and V VUR highly unlikely but does not rule out lower grades of VUR.

Evaluation and management of recurrent urinary tract infections in children: state of the art

Urinary tract infections (UTIs) represent an important cause of febrile illness in young children and can lead to renal scarring and kidney failure. However, diagnosis and treatment of recurrent UTI in children is an area of some controversy. Guidelines from the American Academy of Pediatrics, National Institute for Health and Clinical Excellence and European Society of Paediatric Radiology differ from each other in terms of the diagnostic algorithm to be followed. Treatment of vesicoureteral reflux and antibiotic prophylaxis for prevention of recurrent UTI are also areas of considerable debate. In this review, we collate and appraise recently published literature in order to formulate evidence-based guidance for the diagnosis and treatment of recurrent UTI in children.

Is top-down vs bottom-up radiological evaluation after febrile urinary tract infection really less stressful for the child and family? Challenging the dogma

PURPOSE

We evaluated whether stress levels in children and parents during radiological evaluation after febrile urinary tract infection are really lower using the top-down approach, where (99m)technetium dimercaptosuccinic acid renal scintigraphy is used initially, than the bottom-up approach, where voiding cystourethrography is initially performed and repeated examinations are easier for all.

MATERIALS AND METHODS

We prospectively evaluated 120 children 3 to 8 years old. Pain ratings were obtained using the Faces Pain Scale-Revised, and conversation during the procedure was evaluated using the Child-Adult Medical Procedure Interaction Scale-Revised by 2 independent observers. To evaluate parental anxiety, the State-Trait Anxiety Inventory form was also completed. Following a documented febrile urinary tract infection children were randomized to the top-down or bottom-up group. A third group of 44 children undergoing repeat voiding cystourethrography and their parents were also evaluated.

RESULTS

Child ratings of pain using the Faces Pain Scale-Revised were not significantly different between the top-down group following (99m)technetium dimercaptosuccinic acid renal scintigraphy (2.99 on a scale of 10) and the bottom-up group following voiding cystourethrography (3.21). Also the Faces Pain Scale-Revised was not significantly different in the repeat voiding cystourethrography group (3.35). On the Child-Adult Medical Procedure Interaction Scale-Revised there was negative correlation between child coping and child distress, as well as rate of child distress and adult coping promoting behavior. Parental state anxiety scores were significantly less in the top-down and repeat voiding cystourethrography groups than in the bottom-up group.

CONCLUSIONS

Although the top-down approach and repeat voiding cystourethrography cause less anxiety for caregivers, these values do not correlate to pain scale in children. This finding might be due to lack of appropriate evaluation tools of pediatric pain and anxiety. However, the theory that the top-down approach is less invasive, and thus less stressful, requires further research. The Child-Adult Medical Procedure Interaction Scale-Revised data indicate that influences in adult-child interaction are bidirectional.

Voiding urosonography with second-generation ultrasound contrast versus micturating cystourethrography in the diagnosis of vesicoureteric reflux

Vesicoureteric reflux has been associated with paediatric urinary tract infection. Fluoroscopic micturating cystourethrography (MCU) has been the gold standard of diagnostic test for decades; however, it has been criticized owing to its lower detection rate and radiation dose to children. Therefore, new radiation-free reflux imaging modalities have been developed, in which ultrasound-based contrast-enhanced voiding urosonography (ceVUS) is a good example. However, ultrasonography has been considered as an operator-dependent examination. Therefore, our study aimed to examine the inter-observer agreement of this sonographic technique, which has not been evaluated before. Moreover, the second-generation ultrasound contrast SonoVue has been recently marketed, and the data on its efficacy on intravesical use in ceVUS is relatively scarce. Thus, we also aimed to investigate the diagnostic performance and safety profile of SonoVue-enhanced VUS in the diagnosis of vesicoureteric reflux. Our prospective comparative study compared the diagnostic performance of ceVUS with MCU in young children presenting with first episode of urinary tract infection. We performed sequential ceVUS and MCU examinations in 31 patients (62 pelvi-ureter units). Perfect inter-observer agreement (Cohen’s kappa statistics = 1.0, p < 0.001) was achieved in ceVUS, suggesting its good reliability in reflux detection and grading. Using MCU as reference, ceVUS had 100 % sensitivity and 84 % specificity and carried higher reflux detection rate than MCU (p < 0.001). There was no complication encountered. Conclusion: Voiding urosonography is a reliable, sensitive, safe and radiation-free modality in the investigation of vesicoureteric reflux in children. It should be incorporated in the diagnostic algorithm in paediatric urinary tract infection.

Detecting reflux: does ureteric jet Doppler waveform have a role?

BACKGROUND

Vesicoureteral reflux (VUR) has a prevalence of 30-40 % post-febrile urinary tract infection (UTI). If not detected early and treated, renal scarring, hypertension, and renal failure may occur. Micturating cystourethrography (MCU) is an invasive procedure associated with radiation exposure. Hence, this study aimed at evaluating the utility of ureteric jet Doppler waveform (UJDW) as a screening tool in detecting VUR, and at assessing the feasibility of performing it in children aged 2-4 years.

METHODS

Any child 2-18 years old who needed an MCU was included. Exclusion criteria were active UTI, indwelling catheter, and inability to drink the required amount of fluid. The UJDW was performed prior to the MCU.

RESULTS

One hundred eighty-two ureteric units were analyzed. Sensitivity and specificity of UJDW in detecting VUR was 80.3 and 87.9 %. Twenty-three children (45 ureteric units), aged 2-4 years were compared with 73 children (137 ureteric units), aged 5-18 years. Sensitivity and specificity of UJDW in detecting VUR in 2-4 years was 77.3 and 91.3 %, respectively; while in children ≥5 years, it was 81.8 and 87.1 %, respectively.

CONCLUSIONS

UJDW has a uniformly high specificity regardless of age or etiological groups, making it a good tool for follow-up. UJDW is a feasible technique, even in children aged 2-4 years.