DMSA scan for revealing vesicoureteral reflux in young children with urinary tract infection

Prediction model for severe vesicoureteral reflux in children with urinary tract infection and/or hydronephrosis

BACKGROUND

As voiding cystourethrography is invasive and exposes to radiation and urinary tract infection (UTI), identifying only high-grade reflux is important. We aimed to identify clinical, laboratory and imaging variables associated with high-grade primary reflux in children presenting with UTIs and/or urinary tract dilatation and develop a prediction model for severe reflux.

METHODS

Data of children who underwent voiding cystourethrography due to UTI and/or urinary tract dilatation were retrospectively analyzed for demographic, clinical and imaging findings. Patients with severe (grades 4-5) reflux were compared with the rest for these parameters and a prediction model was developed for severe reflux.

RESULTS

The study included 1044 patients (574 female). Severe reflux was present in 86 (8.2%) patients. Age < 2 years, male sex, non-E. coli uropathogens, UTD-P3 dilatation and multiple kidney scars on DMSA scintigraphy were associated with severe reflux. Using these variables a prediction model for severe reflux with a score ranging from 0-7 and accuracy rate of 93.4% was developed. A score ≥ 5 had sensitivity 44.2%, specificity 97.4%, PPV 60.3%, NPV 95.1% and OR 29.5 for severe reflux. Scores ≥ 5 and ≥ 4 catch 44% and 73% of severe reflux, while prevent invasive voiding cystourethrography in 94.0% and 83.6% of patients, respectively.

CONCLUSION

Age < 2 years, male sex, non-E. coli uropathogen growth, presence of UTD-P3 dilatation on ultrasonography and multiple scars on DMSA scintigraphy are risk factors for severe reflux. A scoring system based on these variables appears to be effective in predicting the presence of severe reflux and eliminating unnecessary voiding cystourethrography.

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.

Pediatric Nephro-Urology: Overview and Updates in Diuretic Renal Scans and Renal Cortical Scintigraphy

Nuclear medicine offers several diagnostic scans for the evaluation of congenital and acquired conditions of the kidneys and urinary track in children. Tc-99m-MAG 3 diuretic renal scans are most commonly used in the evaluation and follow up of urinary track dilatations. They provide functional information on the differential renal function and on drainage quality which is allows distinction between obstructed and non-obstructed kidneys and the need for surgical correction vs conservative management in kidneys with impaired drainage. Standardized imaging and processing protocols are essential for correct interpretation and for meaningful comparisons between follow up scans. Different approaches and conceptions led to some contradicting recommendations between SNMMI and EANM guidelines on diuretic renography in children which caused confusion and to the emergence of self-made institutional protocols. In Late 2018 the two societies published joint procedural guidelines on diuretic renography in infants and children which hopefully will end the confusion. Tc-99m DMSA scans provide important information about the function of the renal cortex allowing detection of acute pyelonephritis, renal scars dysplasia and ectopy as well as accurate determination of the differential renal function. They are commonly used in the evaluation of children with urinary tract infections and affect clinical management. A standardized imaging and processing protocol improves the diagnostic accuracy of these studies. SPECT or pinhole images should be a routine part of the imaging protocol. This is one of the recommendations in the new EANM and SNMMI procedural guidelines for renal cortical scintigraphy in children available online on the SNMMI website and is under publication. This article provides an overview on the clinical role of diuretic renography and cortical scintigraphy in children and describes the imaging protocols focusing on the new recommendations in the procedural guidelines.

Prediction of Vesicoureteral Reflux by Ultrasonography and Renal Scan in Children

Background. In recent studies, renal ultrasonography and dimercapto-succinic acid (DMSA) scan have a role in predicting vesicoureteral reflux in children with febrile urinary tract infection (UTI). Materials and Methods. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were defined for ultrasonography and DMSA scan to predict vesicoureteral reflux in 70 children with febrile UTI. Results. Renal ultrasonography sensitivity, specificity, PPV, NPV, PLR, and NLR for vesicourethral reflux prediction was 0.57, 0, 1, 0, 0.57, and 0.47 and sensitivity, specificity, PPV, NPV, PLR, and NLR of DMSA scan for predicting vesicourethral reflux was 0.75, 0.9, 0.33, 0.98, 7.5, and 0.27, respectively. Conclusions. Ultrasonography cannot predict the presence of VUR, but DMSA scan has a good sensitivity in this context. Therefore, by observation of DMSA scan results, it can be decided whether to perform VCUG or not.

Asian guidelines for urinary tract infection in children

The followings are the level of evidence (LE) and grade of recommendation (GR) on pediatric UTI in Asia. Classification according to the sites of infection (lower versus upper tract), the number of episode (first versus recurrent), the severity (simple versus severe), or the existence of complicating factor (uncomplicated versus complicated) is useful to differentiate children with UTI whether they are at risk of renal damage or not (LE: 2, GR: B). Diagnosis of UTI requires both urinalysis that suggests infection and positive urine culture (LE:3, GR B). For pre-toilet trained children, urine specimen for culture should be collected by urethral catheterization or suprapubic aspiration. For toilet trained children, midstream clean catch urine is reliable (LE: 3, GR: A). Urine culture is considered positive if it demonstrates growth of a single bacterium with the following colony counts: (1) any growth by suprapubic aspiration, (2) >5 × 104 CFU/ml by urethral catheterization, or (3) >105 CFU/ml by midstream clean catch (LE:3, GR: B). For children with febrile UTI, renal and bladder ultrasonography (RBUS) should be routinely performed as soon as possible (LE: 3, GR: C). RBUS should be followed up 6 months later in children with acute pyelonephritis and/or VUR (LE: 3, GR: C). Acute DMSA scan can be performed when severe acute pyelonephritis or congenital hypodysplasia is noted on RBUS or when the diagnosis of UTI is in doubt by the clinical presentation (LE: 3, GR: C). Late DMSA scan (>6 months after the febrile UTI) can be performed in children with severe acute pyelonephritis, high-grade VUR, recurrent febrile UTIs, or abnormal renal parenchyma on the follow-up RBUS (LE: 3, GR: C). Top-down or bottom-up approach for febrile UTI is suggested for the diagnosis of VUR. For top-down approach, VCUG should not be performed routinely for children after the first febrile UTI. VCUG is indicated when abnormalities are apparent on either RBUS or DMSA scan or both (LE: 2, GR: B). VCUG is also suggested after a repeat febrile UTI (LE:2, GR: B). Appropriate antibiotic should be given immediately after urine specimen for culture has been obtained (LE:2, GR: A). Initiating therapy with oral or parenteral antibiotics is equally efficacious for children (>3 months) with uncomplicated UTI (LE: 2: GR: A). The choice of empirical antibiotic agents is guided by the expected pathogen and the local resistance patterns (LE: 2, GR: A). For children with febrile UTI, the total course of antibiotic therapy should be 7-14 days (LE: 2, GR: B). Circumcision may, but not definitively, reduce the risk of febrile UTI in males and breakthrough febrile UTI in males with VUR. Circumcision should be offered to uncircumcised boys with febrile UTI and VUR in countries where circumcision is accepted by the general population (LE: 3, GR: B), while in countries where childhood circumcision is rarely performed, other measures for febrile UTI/VUR should be the preferred choice (LE: 4, GR: C). Bladder bowel dysfunction (BBD) is one of the key factors of progression of renal scarring (LE: 2). Early recognition and management of BBD are important in prevention of UTI recurrence (LE:2, GR: A). Antibiotic prophylaxis to prevent recurrent febrile UTI is indicated in children with moderate to high grade (III-V) VUR (LE: 1b, GR: A). Surgical intervention may be used to treat VUR in the setting of recurrent febrile UTI because it has been shown to decrease the incidence of recurrent pyelonephritis (LE: 2, GR: B).

Prevention of recurrent febrile urinary tract infection in infants: Ultrasonography-oriented approach is more practical than a top-down approach

BACKGROUND

We previously reported that the top-down approach (TDA) for infants with febrile urinary tract infections (fUTI) could prevent recurrent fUTI (r-fUTI) but produced a high number of false-positives on acute-phase ^99m Tc dimercaptosuccinic acid (DMSA) renal scintigraphy. Therefore we compared the ultrasonography-oriented approach (USOA) with TDA from the viewpoint of prevention of r-fUTI.

METHODS

The TDA was applied between July 2010 and February 2014 and the USOA was applied between March 2014 and April 2017 in infants with first fUTI. In the USOA group, voiding cystourethrography (VCUG) was performed in the case of abnormality on acute-phase renal bladder ultrasonography (RBUS) or on chronic- phase DMSA, which were performed in all cases. The frequency of r-fUTI was compared between the TDA group and USOA group retrospectively.

RESULTS

Seventy-four infants (52 male) and 79 infants (60 male) received TDA or USOA, respectively. No significant differences were found between the TDA and USOA groups in male : female ratio, age in months at initial onset of fUTI, observation period, or number of cases of r-fUTI (TDA group, n = 4; USOA group, n = 5). Seventy-four DMSA scintigraphy and 25 VCUG were carried out in the USOA group, and 111 DMSA scintigraphy and 34 VCUG in the TDA group.

CONCLUSIONS

Both USOA and TDA were valid for prevention of r-fUTI, but USOA was superior to TDA with regard to the reduced number of patients undergoing VCUG and DMSA.

Role of Late DMSA Renal Scan in Detecting High-Grade Vesicoureteral Reflux

OBJECTIVE

To determine the performance of late dimercaptosuccinic acid (DMSA) renal scans in identifying high-grade (III-V) vesicoureteral reflux (VUR) in children aged over 3 y with a febrile urinary tract infection (fUTI) history that has not been timely investigated.

METHODS

In this retrospective study of diagnostic accuracy, the clinical records of children aged between 3 and 18 y with fUTI history evaluated consecutively at Nephrology Unit of Hospital General de Niños Pedro de Elizalde, Argentina between 2006 and 2016 were reviewed. Patients with previously diagnosed renal or urinary tract abnormalities or who underwent previous postnatal genitourinary imaging were excluded. Only those assessed by renal and bladder ultrasound (RBUS), voiding cystourethrogram (VCUG) and late 6-mo DMSA scan were analyzed. The ability of the scintigraphy in identifying high-grade VUR was determined by comparing its findings with those of VCUG.

RESULTS

In 122 children (median age 5.37 y, 88.5% girls) RBUS was abnormal in 53 (43.4%) and 58 (47.5%) had VUR (30 of high-grade). Abnormal DMSA scan findings (70 patients, 57.4%) were associated with all grade (p = 0.00001) and with high-grade VUR (p = 0.00001). Sensitivity, specificity, negative (NPV) and positive (PPV) predictive values of late DMSA scans for all grades VUR were 93.1%, 75%, 92.3% and 77.1%, respectively. Only 4 patients with low-grade VUR had normal scans. For high-grade VUR, sensitivity and NPV reached 100%.

CONCLUSIONS

In older children, the normal late DMSA scan predicted the absence of high-grade VUR, obviating the need for a VCUG. This approach could be a possible strategy for children not studied at acute infection time.

Shear Wave Elastography in the Evaluation of the Kidneys in Pediatric Patients with Unilateral Vesicoureteral Reflux

OBJECTIVES

To evaluate the ability of shear wave elastography (SWE) to detect renal parenchymal scar formation in patients with vesicoureteral reflux.

METHODS

We prospectively evaluated 49 patients with unilateral grade 2 or higher-degree VUR. All patients underwent dimercaptosuccinic acid (DMSA) scintigraphy for evaluation of the renal parenchymal scar. After the DMSA scan, 2 radiologists, who were blinded to clinical data and each other's measurements, evaluated the kidneys of the patients using SWE. The kidneys were divided into 3 parts: upper pole, middle region, and lower pole, and 3 regions of interest were placed to each part. Shear wave velocity (SWV) values were calculated using meters per second as a unit and recorded for each region. Afterward, SWV values were compared to DMSA results.

RESULTS

There was no significant difference between the observers' mean SWV values of kidneys with VUR without scar formation (mean ± SD, 2.11 ± 0.06 and 2.09 ± 0.05 m/s) and the contralateral normal kidney SVW values (2.11 ± 0.06 and 2.10 ± 0.05 m/s; P = .936 and .724, respectively). We observed a significant difference between the mean SWV values of the kidneys with VUR accompanied by scar formation (2.28 ± 0.10 and 2.27 ± 0.11 m/s) and the mean SWV values of the contralateral normal kidneys (2.09 ± 0.05 and 2.10 ± 0.04 m/s; P < .001 for both observers).

CONCLUSIONS

Shear wave elastography could detect scar tissue in kidneys; however, the variability of the stiffness due to the kidney's complex structure, and variations in blood perfusion and the glomerular filtration rate of the kidney might limit the use of SWE in current clinical diagnostic algorithms for VUR.

Top-down approach is possible strategy for predicting breakthrough fUTIs and renal scars in infants

BACKGROUND

Acute-phase technetium-99 m dimercaptosuccinic acid (DMSA) scintigraphy is recommended for initial imaging in children with febrile urinary tract infection (fUTI). Recently, the importance of identifying patients at risk of recurrent fUTI (r-fUTI) has been emphasized. To clarify the effectiveness of DMSA scintigraphy for predicting r-fUTI in infants, we investigated the relationship between defects on DMSA scintigraphy and r-fUTI.

METHODS

Seventy-nine consecutive infants (male: female, 60:19) with fUTI were enrolled in this study. DMSA scintigraphy was performed in the acute phase, and patients with defect underwent voiding cystourethrography and chronic-phase (6 months later) DMSA scintigraphy. Patients were followed on continuous antibiotic prophylaxis (CAP).

RESULTS

Defects on acute-phase DMSA scintigraphy were observed in 32 children (40.5%) of 79. The mean follow-up observation period was 17.0 ± 10.1 months. Four patients had r-fUTI (5%). Two of them had defects on DMSA scintigraphy in both the acute phase and chronic phase, and had bilateral vesicoureteral reflux (VUR) grade IV. Two others had r-fUTI without defects on DMSA and did not have VUR. Twelve patients had defect on chronic-phase DMSA scintigraphy and four of them had no VUR.

CONCLUSIONS

The top-down approach is a possible method for predicting r-fUTI in infants and does not miss clinically significant VUR. Also, given that the prevalence of r-fUTI was 5% regardless of the presence of defects on acute-phase DMSA, then, in conjunction with genital hygiene and CAP, acute-phase DMSA might be unnecessary if chronic-phase DMSA is performed for all patients to detect renal scar.

Nuclear Medicine in Pediatric Nephro-Urology: An Overview

In the context of ante-natally diagnosed hydronephrosis, the vast majority of children with a dilated renal pelvis do not need any surgical treatment, as the dilatation resolves spontaneously with time. Slow drainage demonstrated at Tc-99m-mercaptoacetyltriglycine (MAG3) renography does not necessarily mean obstruction. Obstruction is defined as resistance to urinary outflow with urinary stasis at the level of the pelvic-ureteric junction (PUJ) which, if left untreated, will damage the kidney. Unfortunately this definition is retrospective and not clinically helpful. Therefore, the identification of the kidney at risk of losing function in an asymptomatic patient is a major research goal. In the context of renovascular hypertension a DMSA scan can be useful before and after revascularisation procedures (angioplasty or surgery) to assess for gain in kidney function. Renal calculi are increasingly frequent in children. Whilst the vast majority of patients with renal stones do not need functional imaging, DMSA scans with SPECT and a low dose limited CT can be very helpful in the case of complex renal calculi. Congenital renal anomalies such as duplex kidneys, horseshoe kidneys, crossed-fused kidneys and multi-cystic dysplastic kidneys greatly benefit from functional imaging to identify regional parenchymal function, thus directing further management. Positron emission tomography (PET) is being actively tested in genito-urinary malignancies. Encouraging initial reports suggest that F-18-fluorodeoxyglucose (FDG) PET is more sensitive than CT in the assessment of lymph nodal metastases in patients with genito-urinary sarcomas; an increased sensitivity in comparison to isotope bone scans for skeletal metastatic disease has also been reported. Further evaluation is necessary, especially with the promising advent of PET/MRI scanners. Nuclear Medicine in paediatric nephro-urology has stood the test of time and is opening up to new exciting developments.

Dimercaptosuccinic acid scan or ultrasound in screening for vesicoureteral reflux among children with urinary tract infections

BACKGROUND

There is considerable interest in detecting vesicoureteral reflux (VUR) because its presence, especially when severe, has been linked to an increased risk of urinary tract infections and renal scarring. Voiding cystourethrography (VCUG), also known as micturating cystourethrography, is the gold standard for the diagnosis of VUR, and the grading of its severity. Because VCUG requires bladder catheterisation and exposes children to radiation, there has been a growing interest in other screening strategies that could identify at-risk children without the risks and discomfort associated with VCUG.

OBJECTIVES

The objective of this review is to evaluate the accuracy of two alternative imaging tests - the dimercaptosuccinic acid renal scan (DMSA) and renal-bladder ultrasound (RBUS) - in diagnosing VUR and high-grade VUR (Grade III-V VUR).

SEARCH METHODS

We searched MEDLINE, EMBASE, BIOSIS, and the Cochrane Register of Diagnostic Test Accuracy Studies from 1985 to 31 March 2016. The reference lists of relevant review articles were searched to identify additional studies not found through the electronic search.

SELECTION CRITERIA

We considered published cross-sectional or cohort studies that compared the results of the index tests (DMSA scan or RBUS) with the results of radiographic VCUG in children less than 19 years of age with a culture-confirmed urinary tract infection.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the selection criteria to all citations and independently abstracted data. We used the bivariate model to calculate summary sensitivity and specificity values.

MAIN RESULTS

A total of 42 studies met our inclusion criteria. Twenty studies reported data on the test performance of RBUS in detecting VUR; the summary sensitivity and specificity estimates were 0.44 (95% CI 0.34 to 0.54) and 0.78 (95% CI 0.68 to 0.86), respectively. A total of 11 studies reported data on the test performance of RBUS in detecting high-grade VUR; the summary sensitivity and specificity estimates were 0.59 (95% CI 0.45 to 0.72) and 0.79 (95% CI 0.65 to 0.87), respectively. A total of 19 studies reported data on the test performance of DMSA in detecting VUR; the summary sensitivity and specificity estimates were 0.75 (95% CI 0.67 to 0.81) and 0.48 (95% CI 0.38 to 0.57), respectively. A total of 10 studies reported data on the accuracy of DMSA in detecting high-grade VUR. The summary sensitivity and specificity estimates were 0.93 (95% CI 0.77 to 0.98) and 0.44 (95% CI 0.33 to 0.56), respectively.

AUTHORS' CONCLUSIONS

Neither the renal ultrasound nor the DMSA scan is accurate enough to detect VUR (of all grades). Although a child with a negative DMSA test has an < 1% probability of having high-grade VUR, performing a screening DMSA will result in a large number of children falsely labelled as being at risk for high-grade VUR. Accordingly, the usefulness of the DMSA as a screening test for high-grade VUR should be questioned.

Prediction of High-grade Vesicoureteral Reflux in Children Younger Than 2 Years Using Renal Sonography

OBJECTIVES

To investigate the predictive value of renal sonography for vesicoureteral reflux (VUR) and the efficacy of renal sonography, technetium Tc 99m–labeled dimercaptosuccinic acid (DMSA) scanning, and a combination of the two for VUR screening in children younger than 2 years with a first episode of febrile urinary tract infection.

METHODS

Thirty-eight patients younger than 2 years with a first febrile urinary tract infection were included in our study, which was conducted from April through October 2014. Each kidney was considered a separate renal unit. A retrospective review of clinical information and images (renal sonography, DMSA scanning, and voiding cystourethrography) was performed.

RESULTS

Of the 14 renal units (18.4%) with VUR, 4 (28.5%) had high-grade VUR. Among single findings, dilatation of the renal collecting system, wall thickening of the renal collecting system, and DMSA scans significantly predicted VUR (P= .038, .027, and .01, respectively). Dilatation was the most common single finding (46 of 76 renal units). The sensitivity values for dilatation, wall thickening, and DMSA scans were 85.7%, 64.2%, and 50.0%, and the negative predictive values were 93.3%, 89.7%, and 87.9%.

CONCLUSIONS

The negative predictive values indicate that normal renal sonographic and DMSA findings can predict the absence of high-grade VUR. We propose that renal sonographic findings of wall thickening as well as dilatation of the renal collecting system should be considered predictive of high-grade VUR.

Renal ultrasound and DMSA screening for high-grade vesicoureteral reflux

BACKGROUND

Selection of the appropriate radiologic investigation in a child after first febrile urinary tract infection (UTI) remains a contentious issue. This report investigated the effectiveness of renal bladder ultrasound (RBUS) and late 6 month dimercaptosuccinic acid (DMSA) renal scan in the detection of high-grade vesicoureteral reflux (VUR) after first febrile UTI in infants aged <1 year.

METHODS

A total of 387 infants aged <1 year with first febrile UTI who completed diagnostic follow up consisting of RBUS, voiding cystourethrogram (VCUG) and late 6 month DMSA scan were enrolled in the study. The effectiveness of RBUS and DMSA scan in the detection of high-grade VUR, including cost and benefit were assessed.

RESULTS

Abnormal RBUS was identified in 95 infants (24.5%). VUR was identified on VCUG in 79 (20.4%), of whom eight (2.1%) had high-grade VUR (grade IV-V). Abnormal renal parenchyma was identified on late 6 month DMSA scan in 22 infants (5.7%). The sensitivity of abnormal RBUS and of late 6 month DMSA scan in the prediction of high-grade VUR was 50% and 87.5%, and the proportion of infants who avoided unnecessary VCUG was 75.5% and 94.3%, respectively.

CONCLUSIONS

Fifty percent of high-grade VUR was not identified on RBUS screening after first febrile UTI. Although late 6 month DMSA scan had higher sensitivity in the detection of high-grade VUR, with the added benefit of detection of renal scars, the practical application of this method was limited due to its high cost, radiation exposure and the associated delay in decision making.

Recurrent urinary tract infections in young children: role of DMSA scintigraphy in detecting vesicoureteric reflux

BACKGROUND

Performing micturiting cystourethrography (MCUG) in young children with recurrent urinary tract infections is controversial with discrepancy among the major guidelines.

OBJECTIVE

Previous studies have shown that a normal dimercaptosuccinic acid (DMSA) scintigraphy may avoid the need of performing MCUG for detecting vesicoureteric reflux in children with first febrile urinary tract infection. However, the role of DMSA for ruling out vesicoureteric reflux in children with recurrent urinary tract infections has not been studied.

MATERIALS AND METHODS

Approval from institutional ethical review committee was sought and the requirement of informed consent was waived. A total of 50 children under the age of 10 years with recurrent urinary tract infections underwent MCUG scan within 3 months of DMSA scan from January 2011 to September 2012 at our institution. Diagnosis of recurrent urinary tract infections and grading of vesicoureteric reflux was according to previously established standards. Abnormalities on DMSA scan - scarring, hydronephrosis and reduced differential renal function - were compared with presence of vesicoureteric reflux on MCUG.

RESULTS

High-grade vesicoureteric reflux was noted on MCUG in 22 (44%) cases. The findings on DMSA included hydronephrosis and scarring in 25 (50%) and 25 (50%) cases, respectively. Abnormalities on DMSA scan for detecting the presence of high-grade vesicoureteric reflux on MCUG examination had sensitivity, specificity, positive and negative predictive values of 95.45%, 35.71%, 53.85% and 90.91%, respectively. The positive and negative likelihood ratios were 1.48 and 0.13 respectively.

CONCLUSION

DMSA scan had high overall sensitivity and negative predictive value with a low negative likelihood ratio for ruling out high-grade vesicoureteric reflux on MCUG, which may obviate the need of invasive MCUG along with its associated drawbacks.

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.

Practical approach to screen vesicoureteral reflux after a first urinary tract infection

Introduction:

Vesicoureteral reflux (VUR) is a common pediatric urologic disorder. After the first urinary tract infection (UTI), imaging studies are recommended, starting with a renal ultrasound (RUS). Voiding cystourethrography (VCUG) and dimercaptosuccinic acid (DMSA) scan are the other main radiologic studies used to detect VUR. We evaluated the use of RUS as a screening method for VUR in children below 2 years of age, in order to avoid unnecessary VCUG.

Materials and Methods:

Medical records and imaging studies of infants (<2 years) who had their first UTI in a 6 year period were retrospectively reviewed. We evaluated the sensitivity, specificity, and negative predictive values of RUS and DMSA for diagnosing VUR.

Results:

Among 155 children (51% males) with their first UTI, 148 RUS were performed, 128 VCUG and 29 DMSA. VUR was detected in 21% patients; 14.5% low grade and 6.5% high grade. One hundred and twenty-one patients underwent both RUS and VCUG, 101 RUS were normal and 20 abnormal. Of the normal RUS 98% had no or low grade VUR. Among those with an abnormality on RUS 30% had high grade VUR (P < 0.001).

Conclusions:

After the first UTI in infants (<2 years) RUS is a good screening method for VUR. Among such shildren with a normal RUS, we do not recommend VCUG or DMSA. In our opinion, VCUG should be performed only in patients with abnormal findings in RUS or in recurrent UTI.

Predictive risk factors in childhood urinary tract infection, vesicoureteral reflux, and renal scarring management

Approaches to the management of children with urinary tract infection (UTI), vesicoureteral reflux (VUR), and renal scars have been challenged and have become controversial over the past decade. It is difficult to determine when, how, and which patients will benefit from the diagnosis and management of this condition. Therefore, the issues of diagnostic imaging, observation, follow-up, and intervention tend to be decided more on a case-by-case basis, rather than by using an algorithm. Over the past few years, there have been advances in the identification of risk factors that predispose patients with UTI to present with VUR, to develop recurrent UTIs and renal scars, to have deteriorating renal function, to show VUR improvement and/or spontaneous resolution, and to be candidates for and benefit from early surgical intervention.

Accuracy of early DMSA scan for VUR in young children with febrile UTI

OBJECTIVE

To evaluate the accuracy of an acute (99m)Tc-dimercaptosuccinic acid (DMSA) scan in predicting dilating vesicoureteral reflux (VUR) among young children with a febrile urinary tract infection (UTI).

METHODS

The medical records of children (≤ 2 years of age), presenting with febrile UTI between January 2000 and December 2011, were retrospectively reviewed.

RESULTS

A total of 523 children were included in this study, of whom 397 children (75.9%) had abnormal DMSA results and 178 children (34.0%) were identified as VUR on micturating cystourethrography (MCU). Among all the patients, the number of children with dilating VUR was 151 (28.9%). The rate of abnormal results on DMSA for the dilating VUR group was significantly higher than the rates for the non-VUR and low-grade VUR groups (P < .01). In the <6 months age group and ≥ 6 months age group, the sensitivities of DMSA in predicting dilating VUR were 96.15% and 100.0%, respectively, the negative predictive values were 97.26% and 100.0%, respectively, and the negative likelihood ratios were 0.0911 and 0.0000, respectively.

CONCLUSION

For children ≤ 2 years of age with a febrile UTI, an acute DMSA scan is valuable in the exclusion of dilating VUR. The likelihood of the presence of dilating VUR on MCU is rather low when the result of DMSA is negative. DMSA should be conducted to assess the need for an MCU.

Childhood vesicoureteral reflux studies: registries and repositories sources and nosology

Despite several recent studies, the advisability of antimicrobial prophylaxis and certain imaging studies for urinary tract infections (UTIs) remains controversial. The role of vesicoureteral reflux (VUR) on the severity and re-infection rates for UTIs is also difficult to assess. Registries and repositories of data and biomaterials from clinical studies in children with VUR are valuable. Disease registries are collections of secondary data related to patients with a specific diagnosis, condition or procedure. Registries differ from indices in that they contain more extensive data. A research repository is an entity that receives, stores, processes and/or disseminates specimens (or other materials) as needed. It encompasses the physical location as well as the full range of activities associated with its operation. It may also be referred to as a biorepository. This report provides information about some current registries and repositories that include data and samples from children with VUR. It also describes the heterogeneous nature of the subjects, as some registries and repositories include only data or samples from patients with primary reflux while others also include those from patients with syndromic or secondary reflux.

Identifying children with vesicoureteral reflux: a comparison of 2 approaches

PURPOSE

Various screening approaches have been proposed to identify the subgroup of children with urinary tract infection who have vesicoureteral reflux. However, few studies have compared the sensitivity of screening approaches in a representative population of young children. We compared the sensitivities of the top-down ((99m)technetium dimercaptosuccinic acid renal scan to screen) and biomarker based (C-reactive protein level at presentation) approaches in identifying children with vesicoureteral reflux.

MATERIALS AND METHODS

We calculated the sensitivity of the 2 screening approaches in detecting vesicoureteral reflux and subsequently high grade (III or greater) vesicoureteral reflux in children.

RESULTS

The top-down and C-reactive protein based approaches missed 33% and 29% of cases of high grade vesicoureteral reflux, respectively.

CONCLUSIONS

The sensitivity of the top-down approach for detecting high grade vesicoureteral reflux was lower than previously reported. Further study of novel methods to identify children at risk for renal scarring is warranted.

Screening high-grade vesicoureteral reflux in young infants with a febrile urinary tract infection

BACKGROUND

The lack of good evidence for improved outcomes in children and young infants with febrile urinary tract infection (UTI) after aggressive treatment for vesicoureteral reflux (VUR) has raised doubts regarding the need for routine voiding cystourethrography (VCUG), and the appropriate imaging evaluation in these children remains controversial.

OBJECTIVES

This prospective study aimed to determine whether abnormalities found on acute dimercaptosuccinic acid (DMSA) scan and ultrasound (US) can help indicate the necessity of voiding cystourethrography (VCUG) in young infants.

METHODS

For 3.5 years, all infants younger than 3 months presenting with first febrile UTI were prospectively studied. All infants were hospitalized and investigated using US (<3 days after admission), DMSA scan (<5 days after admission), and VCUG (7-10 days after antibiotic treatment) after diagnosis. The association among findings of US, DMSA scan, and VCUG were evaluated.

RESULTS

From 220 infants, there were abnormal results in 136 (61.8%) US and in 111 (50.5%) DMSA scans. By US, ten infants (4.5%) with abscess or structural abnormalities other than VUR were diagnosed. High-grade (III-V) VUR was present in 39 patients (17.7%). The sensitivities for high-grade VUR of renal US alone (76.9%) or DMSA scan alone (82.1%) were not as good as that of the "OR rule" strategy, which had 92.3% sensitivity and 94.3% negative predictive value.

CONCLUSIONS

To screen high-grade VUR in young infants with febrile UTI, US and acute DMSA scan could be performed first. VCUG is only indicated when abnormalities are apparent on either US or DMSA scan or both.

Acute phase 99mTc-dimercaptosuccinic acid scan in infants with first episode of febrile urinary tract infection

BACKGROUND

99mTc-dimercaptosuccinic acid (DMSA) scan is the golden standard for the diagnosis of acute pyelonephritis and renal scaring. We investigated the use of acute phase DMSA scan in infants presented promptly to the hospital because of the first episode of their febrile urinary tract infection (UTI).

METHODS

Ninety-eight infants with microbiologically confirmed first episode of febrile UTI were studied. DMSA scans were carried out within 7 days in these infants after admission. Infants with an abnormal acute DMSA scan underwent a second DMSA scan 6-12 months later.

RESULTS

Overall, acute DMSA scan was abnormal in 16 (16.3%) of the 98 patients. There were no differences in sex, age, fever over 38.5°C, blood inflammation indices, or evidence of vesicoureteral reflux (VUR) between patients with normal and abnormal acute DMSA scan (P>0.05). However, infants with grade III to V VUR as well as those with delayed treatment presented significantly increased renal involvement by acute DMSA scan (P<0.05). The sensitivity and specificity of abnormal acute DMSA scan to predict grade III to V VUR were 50% and 88% respectively. Its positive and negative likelihood ratios were 4.16 and 0.57, respectively. Of 16 children with abnormal initial DMSA scan results, 14 underwent a second DMSA scan. Follow-up DMSA scans were normal in 12 of the 14 children.

CONCLUSIONS

Parenchymal damage found in a minority of infants with febrile UTI presented promptly to the hospital. Acute phase DMSA scan should be carried out only in selected patients. An abnormal acute DMSA scan is a moderate predictor for dilated VUR and its ability to exclude VUR is restricted.

Acute Tc-99m DMSA scan for identifying dilating vesicoureteral reflux in children: a meta-analysis

Controversy exists regarding the type and/or sequence of imaging studies needed during the first febrile urinary tract infection (UTI) in young children. Several investigators have claimed that because acute-phase Tc-99m dimercaptosuccinic acid (DMSA) renal-scan results are abnormal in the presence of dilating vesicoureteral reflux, a normal DMSA-scan result makes voiding cystourethrography (VCUG) unnecessary in the primary examination of infants with UTI. To evaluate the accuracy of acute-phase DMSA scanning in identifying dilating (grades III through V) vesicoureteral reflux documented by VCUG in children with a first febrile UTI, we performed a meta-analysis of the accuracy of diagnostic tests as reported from relevant studies identified through the PubMed and Scopus databases. Patient-based and renal unit-based analyses were performed. Overall, 13 cohort studies were identified. Nine studies involved patients younger than 2 years, 3 involved children aged 16 years or younger, and 1 involved exclusively neonates. Girls constituted 22% to 85% of the involved children. Pooled (95% confidence intervals) sensitivity and specificity rates of DMSA scanning were 79% and 53%, respectively, for the patient-based analysis (8 studies) and 60% and 65% for the renal unit-based analysis (5 studies). The respective areas under the hierarchical summary receiver operating curves were 0.71 and 0.67. Marked statistical heterogeneity was observed in both analyses, as indicated by I(2) test values of 91% and 87%, respectively. Acute-phase DMSA renal scanning cannot be recommended as replacement for VCUG in the evaluation of young children with a first febrile UTI.