Imaging recommendations in paediatric uroradiology. Minutes of the ESPR uroradiology task force session on childhood obstructive uropathy, high-grade fetal hydronephrosis, childhood haematuria, and urolithiasis in childhood. ESPR Annual Congress, Edinburgh, UK, June 2008

Predicting obstruction risk using common ultrasonography parameters in paediatric hydronephrosis with machine learning

OBJECTIVE

To sensitively predict the risk of renal obstruction on diuretic renography using routine reported ultrasonography (US) findings, coupled with machine learning approaches, and determine safe criteria for deferral of diuretic renography.

PATIENTS AND METHODS

Patients from two institutions with isolated hydronephrosis who underwent a diuretic renogram within 3 months following renal US were included. Age, sex, and routinely reported US findings (laterality, kidney length, anteroposterior diameter, Society for Fetal Urology [SFU] grade) were abstracted. The drainage half-times were collected from renography and stratified as low risk (<20 min, primary outcome), intermediate risk (20-60 min), and high risk of obstruction (>60 min). A random Forest model was trained to classify obstruction risk, here named the 'Artificial intelligence Evaluation of Renogram Obstruction' (AERO). Model performance was determined by measuring area under the receiver-operating-characteristic curve (AUROC) and decision curve analysis.

RESULTS

A total of 304 patients met the inclusion criteria, with a median (interquartile range) age of diuretic renogram at 4 (2-7) months. Of all patients, 48 (16%) were low risk, 102 (33%) were intermediate risk, 156 (51%) were high risk of obstruction based on diuretic renogram. The AERO achieved a binary AUROC of 0.84, multi-class AUROC of 0.74 that was superior to the SFU grade, and external validation (n = 64) binary AUROC of 0.76. The most important features for prediction included age, anteroposterior diameter, and SFU grade. We deployed our application in an easy-to-use application (https://sickkidsurology.shinyapps.io/AERO/). At a threshold probability of 30%, the AERO would allow 66 more patients per 1000 to safely avoid a renogram without missing significant obstruction compared to a strategy in which a renogram is routinely performed for SFU Grade ≥3.

CONCLUSIONS

Coupled with machine learning, routine US findings can improve the criteria to determine in which children with isolated hydronephrosis a diuretic renogram can be safely avoided. Further optimisation and validation are required prior to implementation into clinical practice.

Radiological and surgical correlation of pelviureteric junction obstruction in positional anomalies of the kidney in children

Pelviureteric junction obstruction, also known as ureteropelvic junction obstruction, is a congenital narrowing of the urinary excretory tract at the junction between the renal pelvis and the ureter and is a common cause of congenital pelvicalyceal dilatation. The outcome is variable, from spontaneous resolution to renal parenchymal function loss in cases of untreated high-grade obstruction. Abnormalities in renal ascent, rotation and vascularity can be associated with pelviureteric junction obstruction and easily overlooked radiologically. In this pictorial review, we explore the anatomical, radiological and surgical correlations of pelviureteric junction obstruction in the context of a normal kidney and a spectrum of renal abnormalities, including hyper-rotation (also known as renal malrotation), failed renal ascent, fusion anomalies and accessory crossing renal vessels. For each scenario, we provide technical tips on how to identify the altered anatomy at the first ultrasound assessment and correlation with scintigraphic, cross-sectional and postoperative imaging where appropriate. A detailed ultrasound protocol specifically to assess and characterise pelviureteric junction obstruction in paediatric patients is also offered.

Pediatric Nephrolithiasis

The prevalence of pediatric nephrolithiasis has increased dramatically in the past two decades for reasons that have yet to be fully elucidated. Workup of pediatric kidney stones should include metabolic assessment to identify and address any risk factors predisposing patients to recurrent stone formation, and treatment should aim to facilitate stone clearance while minimizing complications, radiation and anesthetic exposure, and other risks. Treatment methods include observation and supportive therapy, medical expulsive therapy, and surgical intervention, with choice of treatment method determined by clinicians' assessments of stone size, location, anatomic factors, comorbidities, other risk factors, and preferences and goals of patients and their families. Much of the current research into nephrolithiasis is restricted to adult populations, and more data are needed to better understand many aspects of the epidemiology and treatment of pediatric kidney stones.

Imaging of urinary tract in children in different clinical scenarios: a guide for general radiologists

Background

Children are frequently referred to the pediatric radiology department due to complaints related to the urinary tract.

Main body

We aimed to describe common clinical scenarios in paediatric urology practice and their recommended imaging diagnostic algorithms. Practical imaging approach to following common clinical scenarios and the common radiological findings are discussed: (A) perinatal urinary tract dilatation and other congenital anomalies; (B) recurrent urinary tract infection; (C) enuresis and daytime urinary incontinence; (D) abdominal masses; (E) flank pain; (F) hematuria; (G) trauma; (H) nonpalpable testis, ambiguous genitalia and common urogenital sinus anomalies; and I) renovascular hypertension

Conclusions

Imaging investigations should be tailored according to the clinical presentation in a stepwise approach aiming for optimum patients’ care.

A single centre experience of percutaneous nephrolithotomy in infants and its long-term outcomes

BACKGROUND

Renal stones in infants requiring Percutaneous nephrolithotomy (PCNL) is rare. There is insufficient literature on the long-term implications of PCNL in growing kidneys of these children.

OBJECTIVES

To review our experience of PCNL amongst infants i.e., < 1year of age and to analyse the safety and efficacy of this procedure and assess its long-term renal outcomes.

STUDY DESIGN

This was a retrospective analysis of a prospectively maintained data base between 2005 and 2020. All infants with unilateral renal stones >12 mm underwent PCNL. Changes in the serum creatinine, estimated glomerular filtration rate and renal size prior to the PCNL and at the last follow up were monitored. The demographics, clinical profile, operative details, post-operative complications and follow up data were collated and analyzed.

RESULTS

86 children were diagnosed with renal stones of whom, 24 infants met our inclusion criteria and were included in the review. The average age was 9.75 months with fever being the commonest presenting symptom. Five infants were diagnosed with metabolic abnormalities, hypercalciuria being the commonest. Majority of the infants (22) had single stones and the lower calyx was the commonest site (50%). The mean stone burden was 19.5 mm. The stone free rate was 91% during the primary PCNL, which increased to 100% after re-do PCNL. The overall complication rate was 16% which was graded by the modified Clavien Dindo scale for surgical complications. The median follow up period was 144 months and average age at the last follow up was 10.5 years. At the last follow up, a mean serum creatinine of 0.4 mg/dl, mean estimated glomerular filtration rate of 98 ml/min/1.72 m² and a mean renal size of 8.3 cm was recorded, which was comparable to that of a normal child, thus signifying no deterioration of renal functions and renal growth. Three children showed the presence of cortical scars on an isotope scan at follow up. However, all the 24 operated renal units demonstrated preserved renal functions.

DISCUSSION & CONCLUSION

PCNL performed during infancy does not hinder the growth potential of the kidney. Each of the 24 children achieved the target renal size and estimated glomerular filtration rate corresponding to the duration and body size at the end of the follow-up. Thus, PCNL in infants <1 year of age is safe and effective with no adverse effects at long term follow-up.

Treatment of infants with ureteropelvic junction obstruction: findings from the PURSUIT network

PURPOSE

Studies based on administrative databases show that infant pyeloplasty is associated with minority race/ethnicity but lack clinical data that may influence treatment. Our objective was to identify clinical and demographic factors associated with pyeloplasty in infants from three large tertiary centers.

METHODS

We reviewed infants with unilateral Society for Fetal Urology (SFU) grade 3-4 hydronephrosis seen at three tertiary centers from 2/1/2018 to 9/30/2019. Patients were excluded if > 6 months old or treated surgically prior to the initial visit. Outcomes were: pyeloplasty < age 1 year and SFU grade on most recent ultrasound (US) within the first year. Covariables included: age at the initial visit, race/ethnicity, treating site, insurance type, febrile UTI, and initial imaging findings. Univariable and multivariable analyses were performed using log-rank tests and Cox proportional hazards models, respectively.

RESULTS

197 patients met study criteria; 19.3% underwent pyeloplasty. Pyeloplasty was associated with: treating site (p = 0.03), SFU 4 on initial US (p = 0.001), MAG-3 (p < 0.001), and T½ > 20 min (p < 0.001) in patients undergoing a MAG-3 (n = 107). MAG-3 (p < 0.001) and location (p = 0.08) were associated with earlier time to pyeloplasty on multivariable Cox analysis. In infants with follow-up US (n = 115), initial SFU grade, MAG-3 evaluation or findings, and pyeloplasty were not associated with improvement of hydronephrosis.

CONCLUSIONS

We found that infant pyeloplasty rates vary between sites. Prolonged T½ was associated with surgery despite prior studies suggesting this is a poor predictor of worsening dilation or function. These findings suggest the need to standardize evaluation and indications for intervention in infants with suspected UPJ obstruction.

Trends in Use of Advanced Imaging in Pediatric Emergency Departments, 2009-2018

Importance

There is increased awareness of radiation risks from computed tomography (CT) in pediatric patients. In emergency departments (EDs), evidence-based guidelines, improvements in imaging technology, and availability of nonradiating modalities have potentially reduced CT use.

Objective

To evaluate changes over time and hospital variation in advanced imaging use.

Design, Setting, and Participants

This cross-sectional study assessed 26 082 062 ED visits by children younger than 18 years from the Pediatric Health Information System administrative database from January 1, 2009, through December 31, 2018.

Exposures

Imaging.

Main Outcomes and Measures

The primary outcome was the change in CT, ultrasonography, and magnetic resonance imaging (MRI) rates from January 1, 2009, to December 31, 2018. Imaging for specific diagnoses was examined using all patient-refined diagnosis related groups. Secondary outcomes were hospital admission and 3-day ED revisit rates and ED length of stay.

Results

There were a total of 26 082 062 visits by 9 868 406 children (mean [SD] age, 5.59 [5.15] years; 13 842 567 [53.1%] male; 9 273 181 [35.6%] non-Hispanic white) to 32 US pediatric EDs during the 10-year study period, with 1 or more advanced imaging studies used in 1 919 283 encounters (7.4%). The proportion of ED encounters with any advanced imaging increased from 6.4% (95% CI, 6.2%-6.2%) in 2009 to 8.7% (95% CI, 8.7%-8.8%) in 2018. The proportion of ED encounters with CT decreased from 3.9% (95% CI, 3.9%-3.9%) to 2.9% (95% CI, 2.9%-3.0%) (P < .001 for trend), with ultrasonography increased from 2.5% (95% CI, 2.5%-2.6%) to 5.8% (95% CI, 5.8%-5.9%) (P < .001 for trend), and with MRI increased from 0.3% (95% CI, 0.3%-0.4%) to 0.6% (95% CI, 0.6%-0.6%) (P < .001 for trend). The largest decreases in CT rates were for concussion (-23.0%), appendectomy (-14.9%), ventricular shunt procedures (-13.3%), and headaches (-12.4%). Factors associated with increased use of nonradiating imaging modalities included ultrasonography for abdominal pain (20.3%) and appendectomy (42.5%) and MRI for ventricular shunt procedures (17.9%) (P < .001 for trend). Across the study period, EDs varied widely in the use of ultrasonography for appendectomy (median, 57.5%; interquartile range [IQR], 40.4%-69.8%) and MRI (median, 15.8%; IQR, 8.3%-35.1%) and CT (median, 69.5%; IQR, 54.5%-76.4%) for ventricular shunt procedures. Overall, ED length of stay did not change, and hospitalization and 3-day ED revisit rates decreased during the study period.

Conclusions and Relevance

This study found that use of advanced imaging increased from 2009 to 2018. Although CT use decreased, this decrease was accompanied by a greater increase in the use of ultrasonography and MRI. There appears to be substantial variation in practice and a need to standardize imaging practices.

Nephrolithiasis: Approach to Diagnosis and Management

Although kidney stones are less common in children than in adults, incidence in children is rising. Kidney stones may lead to significant morbidity in addition to escalating medical costs. Clinical presentation is variable. Bilateral kidney stones in a younger child should prompt work-up for primary hyperoxaluria. Metabolic abnormalities are more frequent in children and can result in frequent stone recurrence. Whole exome sequencing data shows genetic defects in about 30% of stone formers. 24 h urine collection should be conducted when patient receives his usual diet and fluid intake with normal activity. Infrared spectroscopy and X-ray diffraction are used for stone analysis. Urine studies should be delayed by 4-6 wk after stone fragmentation or treatment of any stone related complications. The goal of evaluation is to identify modifiable risk factors for which targeted therapy may be instituted. Primary indications for surgical intervention include pain, infection and obstruction. Extracorporeal shockwave lithotripsy (ESWL), ureteroscopy, and percutaneous nephrolithotomy (PCNL) are most commonly used, and selection is based on stone size, anatomy, composition and anatomy. Advances in technology have allowed a shift to minimally invasive surgeries. Comprehensive management requires multidisciplinary team. Children with kidney stones require long term follow-up with periodic assessment of stone forming activity and ascertaining stone burden. High index of suspicion should be there to diagnose diseases like primary hyperoxaluria, Dent's disease, renal tubular acidosis (RTA) etc. as these diseases have ramifications on kidney function and growth.

Pediatric Nephrolithiasis: Risk Factors, Evaluation, and Prevention

Pediatric nephrolithiasis is a disease of increasing prevalence and economic burden, with data showing a rising trend among girls and adolescents. Kidney stones in children tend to have a high recurrence rate related to underlying risk factors, and the aim of evaluation should be to understand such causes so that targeted therapy can be provided to decrease recurrence and complications. Metabolic, anatomic, and genetic abnormalities as well as environmental risk factors have all been implicated in the pathogenesis of nephrolithiasis. Recent studies have focused on identifying monogenic causes of nephrolithiasis and/or nephrocalcinosis in young patients that would result in personalization of treatment as well as future diagnostic implications for family members. Treatment aims to decrease stone burden and recurrence as well as minimize complications and is guided by stone size and location as well as surgical expertise. Multidisciplinary care for these patients has been on the rise to provide a more comprehensive medical and surgical support. [Pediatr Ann. 2020;49(6):e262-e267.].

National Imaging Trends of Recurrent Pediatric Urolithiasis

OBJECTIVES

The aim of this study was to examine computed tomography (CT) and ultrasound (US) utilization trends in incident and prevalent pediatric emergency department (ED) urolithiasis patients before and after imaging guideline release.

METHODS

We reviewed imaging modalities for children with 2 or more ED encounters between January 1, 2006, and September 1, 2013, for urolithiasis using the Pediatric Health Information System database. Z scores compared the proportion of patient encounters receiving CT and US before (January 1, 2006, to December 31, 2010) and after (January 1, 2011, to September 1, 2013) the release of imaging guidelines. McNemar test for paired proportions compared the percentage of US and CT use between initial versus subsequent visits. Piecewise logistic regression was used to determine the probability of US use and CT use over time before and after the implementation of imaging guidance.

RESULTS

Analysis was completed on 2041 patients with 4930 unique encounters for urolithiasis. During 1758 encounters (35.7%), CT was performed initially. Ultrasound was performed 1585 times (32.2%). Fourteen percent fewer CT procedures were performed during first urolithiasis visits after guideline release (P < 0.01), whereas US use increased by 15% (P < 0.01). Fewer CT procedures were performed at later visits compared with the first (P < 0.05), and US was used more during second or later visits than the first (P < 0.05).

CONCLUSIONS

Medical providers at large academic pediatric EDs have decreased use of CT and increased use of US over the study time frame to diagnose urolithiasis and are now similar during initial visits (US 36.4% vs CT 36.2%, P = 0.94). Physicians are still more likely to use US as the initial urolithiasis imaging modality during second and later encounters.

Evaluation of a child with suspected nephrolithiasis

PURPOSE OF REVIEW

As the incidence of nephrolithiasis in children doubles every 10 years it is becoming a common disease associated with significant morbidity along with considerable economic burden worldwide. The aim of this review is to summarize current data on the epidemiology and causes of renal stones in children and to provide a frame for the first clinical evaluation of a child with suspected nephrolithiasis.

RECENT FINDINGS

Dietary and environmental factors are the driving force of changing epidemiology. Diagnosis should be based on medical history, presenting signs, examination, first laboratory and radiological workup. Ultrasound should be the initial diagnostic imaging performed in pediatric patients while low-dose computed tomography is rarely necessary for management. Metabolic factors including hypercalciuria, hypocitraturia, low fluid intake as well as specific genetic diseases should be explored after the resolution of initial signs and symptoms.

SUMMARY

Appropriate initial evaluation, imaging technique, identification of risk factors and other abnormalities are essential for early diagnosis and prevention of stone-related morbidity in children with suspected nephrolithiasis.

Impact of the Image Gently® Campaign on Computerized Tomography Use for Evaluation of Pediatric Nephrolithiasis

PURPOSE

The Image Gently® campaign was launched by several radiological societies in 2007 to promote safe imaging in children. A goal of the campaign was to reduce ionizing radiation exposure in children. Given the recurrent nature of kidney stones, affected children are at risk for unnecessary ionizing radiation exposure from computerized tomography. We sought to determine whether the Image Gently campaign led to a decrease in the use of computerized tomography for evaluating children with nephrolithiasis. We hypothesized that the campaign was the primary cause of a reduction in the use of computerized tomography.

MATERIALS AND METHODS

We analyzed medical claims data from 2001 to 2015 identifying children with nephrolithiasis covered by the same commercial insurance provider. Using a difference in differences design, we estimated changes in computerized tomography use after the campaign started among patients less than 18 years old compared to a control group age 18 years or older with nephrolithiasis.

RESULTS

We identified 12,734 children and 787,720 adults diagnosed with nephrolithiasis. Before 2007 quarterly rates of computerized tomography use during a stone episode (per 1,000 patients) were increasing at a parallel rate in children and adults (5.1 in children vs 7.2 in adults, p = 0.123). After the Image Gently campaign started the use of computerized tomography decreased in both groups but at a slightly higher rate in adults (difference in differences 2.96, 95% CI 0.00 to 5.91, p = 0.050).

CONCLUSIONS

Although there has been a reduction in the use of computerized tomography among children with nephrolithiasis, given a similar trend seen in adults this change cannot be primarily attributed to the Image Gently campaign.

Ultrasound versus computed tomography for the detection of ureteral calculi in the pediatric population: a clinical effectiveness study

OBJECTIVE

To determine the diagnostic performance of ultrasound for diagnosing ureteral calculi in children using a clinical effectiveness approach.

METHODS

Billing records and imaging reports were used to identify children (≤ 18 years old) evaluated for suspected urolithiasis using ultrasound between March 2012 and March 2017. Patients without unenhanced CT within 24 h (reference standard) were excluded. Imaging (ultrasound and CT) reports were reviewed for presence, number, size, and location of calculi. Diagnostic performance of ultrasound (versus CT) was calculated on an individual ureter basis both by direct calculus visualization as well as direct visualization combined with suspected presence of ureteral stone based on indirect ultrasound findings.

RESULTS

41 ureteral calculi were present in 38 of 69 (55.1%) patients. Mean patient age was 14.7 ± 3.6 years, and 35 of 69 (51%) patients were boys. Based on direct calculus visualization, ultrasound had a sensitivity of 12.8% (95% CI 5.6-26.7%), specificity of 100% (95% CI 96.3-100%), positive predictive value (PPV) of 100% (95% CI 56.6-100%), and negative predictive value (NPV) of 74.4% (95% CI 66.4-81.1%). When ultrasound examinations reported as suspicious for ureteral calculi based on indirect findings also were considered positive, ultrasound had a sensitivity of 41.0% (95% CI 27.1-56.6%), specificity of 95.0% (95% CI 88.7-97.8%), PPV of 76.2% (95% CI 54.9-89.4%), and NPV of 80.3% (95% CI 72.2-86.5%).

CONCLUSIONS

In clinical practice, ultrasound has low sensitivity for directly visualizing ureteral calculi subsequently identified by CT, although sensitivity improves when considering suspicious examinations as positive.

Acoustic shadowing in pediatric kidney stone ultrasound: a retrospective study with non-enhanced computed tomography as reference standard

BACKGROUND

The usefulness of acoustic shadowing as a feature of pediatric kidney stone ultrasound (US) may be underestimated.

OBJECTIVE

The hypothesis was that the majority of stones in children have acoustic shadowing and that its specificity is high (>90%) in pediatric kidney stones.

MATERIALS AND METHODS

Our retrospective observational study included children who had undergone abdominal non-enhanced computed tomography (CT) for kidney stones in a pediatric renal stone referral centre between 2015 and 2016. US examinations prior to CT were retrospectively assessed for US features such as acoustic shadowing, twinkle artifact and stone size. These features were compared to CT as reference standard.

RESULTS

Thirty-one patients (median age: 13 years, range: 1-17 years) with 77 suspected kidney stones were included. The median stone size was 5 mm (interquartile range [IQR]: 5 mm). For acoustic shadowing, sensitivity was 70% (95% confidence interval [CI] 56-80%) and specificity was 100% (95% CI 56-100%). All kidney stones with a diameter ≥9 mm demonstrated shadowing. Sensitivity for twinkle artifact was 88% (95% CI 72-96%), but specificity for twinkle artifact could not be calculated due to the lack of true negatives. All false-positive stones on US demonstrated twinkle artifact, but none showed shadowing.

CONCLUSION

Acoustic shadowing was demonstrated in the majority of pediatric kidney stones. Specificity was high, but this was not significant. Twinkle artifact is a sensitive US tool for detecting (pediatric) kidney calculi, but with a risk of false-positive findings.

Natural course of isolated mild congenital hydronephrosis: A 2-year prospective study at a single center in Japan

OBJECTIVES

To determine a follow-up plan for mild congenital hydronephrosis in Japanese individuals.

METHODS

Neonates at Kansai Medical University Hospital (Hirakata, Osaka, Japan) who were diagnosed with mild congenital hydronephrosis - defined as a Society for Fetal Urology grade 1 or 2 - at 1-month old by abdominal ultrasonography between 2014 and 2016 were enrolled. These patients were encouraged to undergo repeated abdominal ultrasonography for 2 years every 3 months to investigate the course of congenital hydronephrosis.

RESULTS

Among 1009 neonates, congenital hydronephrosis was detected in 118 affected renal units of 100 (9.9%) patients. According to the definition of the Society for Fetal Urology, 118 affected renal units were graded as grade 1 in 87 (74%), grade 2 in 30 (25%), grade 3 in one (1%) and grade 4 in 0 units. Among them, 117 affected renal units of mild congenital hydronephrosis comprising grades 1 and 2 were subjected to ultrasonographic evaluation to monitor the natural course. The rates of resolution at 7, 10, 13, 16, 19, 22 and 25 months after birth in Society for Fetal Urology grades 1 and 2 cases were 60% and 8%, 77% and 19%, 90% and 32%, 92% and 40%, 95% and 52%, 96% and 56%, and 99% and 60%, respectively.

CONCLUSIONS

Grade 1 congenital hydronephrosis does not need to be followed up, because it mostly shows spontaneous resolution by 2 years of follow up without any complications. However, ultrasonographic examinations at 1-year intervals for grade 2 congenital hydronephrosis are recommended to determine the subsequent follow-up plan of patients.

Pediatric Stone Disease

Once considered rare, pediatric nephrolithiasis has become a critical field of study in the last decade due to the rapid increase in incidence. Understanding the changing epidemiology and lifelong implications of pediatric stone disease is critically important to effectively manage the individual patient as well as identify risk factors for childhood onset that could be modified. Determining the role of diagnostic imaging in children is a unique challenge as limiting radiation and imaging stewardship should be priorities. Approaches to management have also changed, as technology continues to evolve and both medical and surgical options expand.

Comparison of ultrasound versus computed tomography for the detection of kidney stones in the pediatric population: a clinical effectiveness study

BACKGROUND

The incidence of pediatric nephrolithiasis in the United States is increasing. There is a paucity of literature comparing the diagnostic performance of computed ultrasound (US) to tomography (CT) in the pediatric population.

OBJECTIVE

To determine the diagnostic performance of renal US for nephrolithiasis in children using a clinical effectiveness approach.

MATERIALS AND METHODS

Institutional review board approval with a waiver of informed consent was obtained for this retrospective, HIPAA-complaint investigation. Billing records and imaging reports were used to identify children (≤18 years old) evaluated for nephrolithiasis by both US and unenhanced CT within 24 h between March 2012 and March 2017. Imaging reports were reviewed for presence, number, size and location of kidney stones. Diagnostic performance of US (reference standard=CT) was calculated per renal unit (left/right kidney) and per renal sector (four sectors per kidney). For sector analysis, US was considered truly positive if a stone was identified at CT in the same or an adjacent sector.

RESULTS

There were 68 renal stones identified by CT in 30/69 patients (43%). Mean patient age was 14.7±3.6 years, and 35 were boys. For detecting nephrolithiasis in any kidney, US was 66.7% (48.8-80.8%) sensitive and 97.4% (86.8-99.9%) specific (positive predictive value=95.2% [77.3-99.8%], negative predictive value=79.2% [65.7-88.3%], positive likelihood ratio=26.0). Per renal sector, US was 59.7% (46.7-71.4%) sensitive and 97.4% (95.5-98.5%) specific (positive predictive value=72.3% [58.2-83.1%], negative predictive value=95.4% [93.2-96.9%], positive likelihood ratio=22.5). Of the 30 stones not detected by US, only 3 were >3 mm at CT.

CONCLUSION

In clinical practice, US has high specificity for detecting nephrolithiasis in children but only moderate sensitivity and false negatives are common.

Standardization of pediatric uroradiological terms: a multidisciplinary European glossary

To promote the standardization of nephro-uroradiological terms used in children, the European Society of Paediatric Radiology uroradiology taskforce wrote a detailed glossary. This work has been subsequently submitted to European experts in pediatric urology and nephrology for discussion and acceptance to improve the quality of radiological reports and communication between different clinicians involved in pediatric urology and nephrology.

Standardization of pediatric uroradiological terms: A multidisciplinary European glossary

To promote the standardization of nephro-uroradiological terms used in children, the European Society of Pediatric Radiology uroradiology taskforce wrote a detailed glossary. This work has been subsequently submitted to European experts in pediatric urology and nephrology for discussion and acceptance to improve the quality of radiological reports and communication among different clinicians involved in pediatric urology and nephrology.

Primary non-surgical management of unilateral ureteropelvic junction obstruction in children: a systematic review

Ureteropelvic junction obstruction (UPJO) is the most common obstructive uropathy and its optimal management remains controversial. However, there is a current trend towards non-surgical management. We aimed to determine the effects of the non-surgical management in children with unilateral UPJO. For a systematic review, we searched MEDLINE, EMBASE, CENTRAL, clinical trials registries, and selected conference proceedings for eligible studies. Any type of study reporting the outcomes renal function, secondary surgical intervention, drainage pattern or hydronephrosis of non-surgical management in children with unilateral UPJO was included. Data from 20 studies were extracted and evaluated by two independent authors. The pooled prevalence was 21% for split renal function deterioration, 27.9% for secondary surgical intervention, 3.2% for progressive hydronephrosis, and 82.2% for improved drainage pattern. Not all patients with surgical intervention regained split renal function from enrolment. Renal imaging methods did not strongly correlate with each other. Many studies had to be excluded because of a lack of detection of an obstruction or mixed populations with bilateral UPJO or other uropathies. The variable definitions of UPJO, different criteria for surgical intervention, incongruity of management protocols, and the imprecise reporting of outcomes were limiting factors in the comparability of the results, leading to heterogeneity in meta-analyses. Although the available evidence cannot recommend or refute the current non-surgical management, the systematic review clarifies aspects of the ongoing controversy by providing realistic estimates for non-surgical management in children with unilateral UPJO. Additionally, it reveals unclear potential risks, particularly for long-term outcomes, which were rarely reported.

Classification of pediatric urinary tract dilation: the new language

The multidisciplinary consensus on the classification of prenatal and postnatal urinary tract dilation (UTD classification system) was created to unify the language used to describe urinary tract dilation on antenatal and postnatal ultrasound examinations and thereby facilitate communication among providers and improve outcomes research. The background and new classification system are described in this review, with imaging examples.

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.

Use of Ultrasound in Pediatric Renal Stone Diagnosis and Surgery

Pediatric urolithiasis is on the rise globally and incidence rates have risen by 6-10% annually over the past couple of decades. Given the increasing incidence, high likelihood of recurrence, and long life expectancy of children, the use of ionizing radiation in the diagnosis, management, and follow up of pediatric urolithiasis has been scrutinized recently and many institutions and organizations have emphasized the use of non-ionizing imaging modality such as ultrasound. This review examines the use of ultrasound in the diagnosis and treatment of pediatric urolithiasis. Specifically, the role of ultrasound in shockwave lithotripsy, percutaneous nephrolithotomy, and, more recently, ureteroscopy will be examined.

Imaging in the diagnosis of pediatric urolithiasis

Pediatric urolithiasis is an important and increasingly prevalent cause of pediatric morbidity and hospital admission. Ultrasound (US) is the recommended primary imaging modality for suspected urolithiasis in children. There is, however, widespread use of CT as a first-line study for abdominal pain in many institutions involved in pediatric care. The objective of this review is to outline state-of-the-art imaging modalities and methods for diagnosing urolithiasis in children. The pediatric radiologist plays a key role in ensuring that the appropriate imaging modality is performed in the setting of suspected pediatric urolithiasis. Our proposed imaging algorithm starts with US, and describes the optimal technique and indications for the use of CT. We emphasize the importance of improved communication with a greater collaborative approach between pediatric and general radiology departments so children undergo the appropriate imaging evaluation.

Clinical effectiveness in the diagnosis and acute management of pediatric nephrolithiasis

The incidence of pediatric nephrolithiasis has risen over the past few decades leading to a growing public health burden. Children and adolescents represent a unique patient population secondary to their higher risks from radiation exposure as compared to adults, high risk of recurrence, and longer follow up time given their longer life expectancies. Ultrasound imaging is the first-line modality for diagnosing suspected nephrolithiasis in children. Although data is limited, the best evidence based medicine supports the use of alpha-blockers as first-line MET in children, especially when stones are small and in a more distal ureteral location. Surgical management of pediatric nephrolithiasis is similar to that in adults with ESWL and URS first-line for smaller stones and PCNL reserved for larger renal stone burden. Clinical effectiveness in minimizing risks in children and adolescents with nephrolithiasis centers around ED pathways that limit CT imaging, strict guidance to ALARA principles or use of US during surgical procedures, and education of both patients and families on the risks of repeat ionizing radiation exposures during follow up and acute colic events.

Posterior urethral valves: are neonatal imaging findings predictive of renal function during early childhood?

BACKGROUND

Obstructive renal dysplasia as observed on US is associated with posterior urethral valves and is regarded as predicting poor renal functional outcome.

OBJECTIVE

To investigate whether any characteristic of urinary tract imaging at birth is predictive of renal function in children with prenatally diagnosed posterior urethral valves.

MATERIALS AND METHODS

We reviewed clinical data including renal function (at birth and up to 3 years of age) and clinical outcome (urinary infection, dialysis, renal transplantation). Imaging data included US (dilatation of the urinary tract, renal cortical echogenicity, signs of cystic dysplasia, urinoma) and cystourethrography findings (vesicoureteral reflux, bladder anomalies, presence of valves) from imaging performed directly after birth.

RESULTS

We retrospectively studied 30 children. Three of the 30 (10%) were in renal failure by the age of 3 years. Twelve of 14 (85%) children with parenchymal anomalies (cortical hyperechogenicity or cystic changes) and 8/9 (89%) children with bilateral high-grade reflux had normal renal function at age 3 years. One child without cystic dysplasia or reflux had abnormal renal function from birth. None of the six children with urinoma developed renal failure by the age of 3 years.

CONCLUSION

Presence of cortical hyperechogenicity, cystic changes or bilateral reflux cannot be considered prognostic of renal failure by the age of 3 years.

ARFI: from basic principles to clinical applications in diffuse chronic disease-a review

Abstract

The many factors influencing the shear wave velocity (SWV) measured with Acoustic Radiation Force Impulse (ARFI) are examined in order to define the most correct examination technique. In particular, attention is given to the information achieved by experimental models, such as phantoms and animal studies. This review targets the clinical applications of ARFI in the evaluation of chronic diffuse disease, especially of liver and kidneys. The contribution of ARFI to the clinical workout of these patients and some possible perspectives are described.

Teaching Points

• Stiffness significantly varies among normal and abnormal biological tissues.

• In clinical applications physical, geometrical, anatomical and physiological factors influence the SWV.

• Elastographic techniques can quantify fibrosis, which is directly related to stiffness.

• ARFI can be useful in chronic diffuse disease of liver and kidney.

Surgery versus non-surgical management for unilateral ureteric-pelvic junction obstruction in newborns and infants less than two years of age

BACKGROUND

Unilateral ureteric-pelvic junction obstruction (UPJO) is the most common cause of obstructive uropathy and may lead to renal impairment and loss of renal function. The current diagnostic approach with renal imaging cannot reliably determine which newborns and infants less than two years of age have a significant obstruction and are at risk for permanent kidney damage. There is therefore no consensus on optimal therapeutic management of unilateral UPJO.

OBJECTIVES

To assess the effects of surgical versus non-surgical treatment options for newborns and infants less than two years of age with unilateral UPJO.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 6, 2016), MEDLINE/Ovid, and EMBASE/Ovid databases from their inception to 13 June 2016. We searched the reference lists of potentially relevant studies without using any language restriction. We also searched the following trial registers for relevant registered studies: www.clinicaltrials.gov/; ISRCTN registry (controlled-trials.com/); www.trialscentral.org/; apps.who.int/trialsearch/; www.drks.de/; and www.anzctr.org.au/trialSearch.aspx.

SELECTION CRITERIA

We selected randomised and quasi-randomised controlled trials comparing surgical with non-surgical interventions for the treatment of unilateral UPJO.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility and risk of bias of included studies and extracted data. In case of disagreements we consulted a third review author. The data reported in the two included studies did not allow us to perform a meta-analysis.

MAIN RESULTS

We found only two studies at high risk of bias that were eligible for inclusion in this review. The total sample size, including both trials, was small (n = 107 participants less than six months of age from the UK and USA), and not all prespecified outcome measures were assessed. Reported measures only accounted for the short-term follow-ups. The mean split renal function was not statistically different between the surgical and non-surgical group at the six-month or one-year time point (very low-quality evidence). The surgical group showed a significantly less obstructed drainage pattern and a lower urinary tract dilatation than the non-surgical group (very low-quality evidence). Transfer from the non-surgical group to the surgical group was reported for about one out of five participants. Split renal function after secondary surgical intervention was reported with variable results, but most of the participants reverted to pre-deteriorated values. The studies either provided no or insufficient data on the following outcome measures: postoperative complications, UPJO-associated clinical symptoms, costs of interventions, radiation exposure, quality of life, and adverse effects.

AUTHORS' CONCLUSIONS

We found limited evidence assessing the benefits and harms of surgical compared to non-surgical treatment options for newborns and infants less than two years of age with unilateral UPJO. The majority of participants in the non-surgical treatment group did not experience any significant deterioration of split renal function, and only about 20% of them underwent secondary surgical intervention, with minor risk of permanent deteriorated split renal function. The study follow-up period was too short to assess the long-term effects on split renal function in both treatment groups. We need further randomised controlled trials with sufficient statistical power and an adequate follow-up period to determine the optimal therapy for newborns and infants less than two years of age with unilateral UPJO.

Pediatric Kidney Stones - Avoidance and Treatment

Pediatric stone disease is increasing in incidence and healthcare costs. With more years at-risk for stone recurrence during their lifetimes, children with nephrolithiasis constitute a high-risk patient population that requires focused intervention through both medical and surgical means. Through high-quality future studies to compare methods of stone prevention and treatment, the burden of stone disease on the youngest members of society may be ameliorated.

Ureteroscopy for Paediatric Renal Tract Stones - Outcomes from a Tertiary European Centre

Aims: The use of ureteroscopy in treating paediatric stone disease has risen in recent years. We retrospectively reviewed the results of ureteroscopic stone management for our regional paediatric stone service. Material and Methods: Between April 2010 and October 2013, consecutive patients undergoing ureteroscopy and stone fragmentation were identified. Data were recorded from electronic records for patient demographics, pre-operative assessment, stone characteristics, and intra- and post-operative complications. Results: Twenty-one patients (mean age 8.6 years; range: 1.4-16) had 32 procedures in our series (13 males and 8 females). Five (24%) had a metabolic abnormality and 8 (38%) had an anatomical abnormality. The mean initial stone size was 9.6 mm (range: 5-20) and 10 were left sided. Of the 32 procedures, 18 (56%) had a pre-operative stent. A positive pre-operative urine culture was seen in 4 (13%). CT was used in 6 (19%) with the rest having a combination of USS and/or plain KUB. Of these 21 patients, 13 (62%) were stone free after the first procedure, 17 (81%) after a second and 20 (95%) after a third (mean 1.5 procedures/patient). One patient with a 6-mm residual fragment chose to have surveillance. Eighteen (50%) had post-operative stent insertion. The mean length of stay was 1.5 days (range: 0-5). A minor complication (Clavien 1) was observed in 1 patient. No other complications were recorded. Conclusions: Ureteroscopy for stone disease in children is feasible with a low complication rate and high stone-free rate.

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.

Use of computed tomography (CT) for urolithiasis in pediatric patients

Numbers of annual CT examinations have been increasing incrementally each year during the last 10-20 years. Use of unenhanced CT has been increasingly used for evaluation of urolithiasis, and concerned had been raised about the risks of increased radiation exposure in pediatric patients. Sensitivities and specificity for ureteral stones on conventional CT have been reported up to 98-100%, respectively. Low dose protocols have been developed with the goal of reducing radiation dose with adequate image quality. Although the sensitivity and the specificity of CT is the highest, many can be diagnosed with combination of KUB and ultrasound. CT can be utilized in equivocal cases. Low-dose radiation CT protocols have been reported with high sensitivity and specificity and should be used in pediatric patients when a CT scan is needed.

Urinary tract infection and vesicoureteral reflux in children with mild antenatal hydronephrosis

OBJECTIVE

The postnatal management of mild antenatal hydronephrosis (ANH) remains controversial. The purpose of this study was to evaluate the incidence of UTI and VUR in children with mild ANH in order to determine the necessity of antibiotic prophylaxis (ABP) and VCUG.

METHOD

The data of 1511 patients with various grades of ANH who were referred to Department of Urology, Boston Children's Hospital between January 1998 and January 2010 were reviewed and 760 patients who had mild ANH were identified. The inclusion criteria were: 1) A confirmed report of ANH or actual prenatal ultrasound (US) images. 2) Postnatal evaluation and management conducted at the hospital. 3) Persistent mild hydronephrosis on the first US done between two weeks and three months of age. 4) No other US findings such as ureteral dilatation, duplication anomalies or bladder abnormalities. 5) At least one three-month follow up. Univariate statistical analysis was performed using a Student's t test.

RESULTS

Of the 760 patients who were identified, 608 (80%) were males, and 225 (30%) had bilateral mild hydronephrosis. Of these, 475 patients (63%) underwent an initial screening VCUG. VUR was identified in 13 patients (1.7%) with grades varying from 1 to 5. At follow up, hydronephrosis resolved in 67% of the renal units and worsened in 3.3%. Among the 692 patients with available follow-up data, 23 (3.3%) had a documented UTI. Twelve of these children had an initial screening VCUG that was negative for VUR. Of these 12 patients, seven underwent a subsequent RNC with none having VUR; five of the 12 patients did not undergo a repeat evaluation for VUR (four had a UTI after the screening VCUG and one had an afebrile UTI). Eleven of the 23 children with mild ANH did not have an initial screening VCUG, and all underwent a subsequent VCUG/RNC. Only two children were then found to have VUR Grade 4-5.

CONCLUSION

The incidence of UTI and VUR in children with mild ANH is low. Consequently, routine VCUG screening for VUR and the use of long-term ABP is not necessary for all patients with asymptomatic mild AHN. Evaluation for VUR in children with mild ANH should be reserved for those who subsequently present with a UTI.

Use of and regional variation in initial CT imaging for kidney stones

OBJECTIVE

We sought to determine the prevalence of initial computed tomography (CT) utilization and to identify regions in the United States where CT is highly used as the first imaging study for children with nephrolithiasis.

METHODS

We performed a cross-sectional study in 9228 commercially insured children aged 1 to 17 years with nephrolithiasis who underwent diagnostic imaging in the United States between 2003 and 2011. Data were obtained from MarketScan, a commercial insurance claims database of 17,827,229 children in all 50 states. We determined the prevalence of initial CT use, defined as CT alone or CT performed before ultrasound in the emergency department, inpatient unit, or outpatient clinic, and identified regions of high CT utilization by using logistic regression.

RESULTS

Sixty-three percent of children underwent initial CT study and 24% had ultrasound performed first. By state, the proportion of children who underwent initial CT ranged from 41% to 79%. Regional variations persisted after adjusting for age, gender, year of presentation, and insurance type. Relative to children living in West South Central states, the highest odds of initial CT utilization were observed for children living in the East South Central US Census division (odds ratio: 1.27; 95% confidence interval: 1.06-1.54). The lowest odds of initial CT were observed for children in the New England states (odds ratio: 0.48; 95% confidence interval: 0.38-0.62).

CONCLUSIONS

Use of CT as the initial imaging study for children with nephrolithiasis is highly prevalent and shows extensive regional variability in the United States. Current imaging practices deviate substantially from recently published guidelines that recommend ultrasound as the initial imaging study.

ESPR uroradiology task force imaging recommendations in paediatric uroradiology, part VII: standardised terminology, impact of existing recommendations, and update on contrast-enhanced ultrasound of the paediatric urogenital tract

Our purpose is to harmonise and standardise terminology in paediatric uroradiology, to provide and update recommendations for contrast-enhanced US to standardise imaging and encourage further research, and to assess the impact of the existing recommendations in paediatric urogenital imaging. Based on thorough review of literature and variable practice at several centres and after discussion within urogenital imaging groups as well as with other subspecialties, we propose a standardisation of terminology in urogenital imaging. An update with recommendations on paediatric contrast-enhanced US has been issued based on available literature and reports. Finally, a questionnaire has been used to assess the knowledge, applicability and usefulness of, and the adherence to existing recommendations of the European Society of Paediatric Radiology (ESPR) Uroradiology Task Force. In conclusion, the ESPR is working to improve patient safety and optimise paediatric urogenital imaging. Standardisation of terminology and provision of updated knowledge on contrast-enhanced US in childhood will contribute to this task, ideally reducing the need for invasive or radiating imaging. Not all existing recommendations are commonly known, which limits adherence to these recommendations and the availability of comparable data and evidence for future adaptation of imaging strategies in paediatric uroradiology.

The impact of hydration on renal measurements and on cortical echogenicity in children

BACKGROUND

Kidney ultrasonography is frequently performed in children; to date there are no specific guidelines regarding hydration before the examination.

OBJECTIVE

Because certain renal measurements can be indicative of pathology, we used sequential US images to investigate the effect of standardised hydration in children relative to renal size, echogenicity and pelvic expansion.

MATERIALS AND METHODS

Thirty-one children (7 years to 14 years old) underwent US examinations before hydration (T0) and at 30 min (T30) and 60 min (T60) after ingesting water. We measured bladder volume, inter-polar kidney size, renal volume and anterior-posterior diameter of the pelvis. Cortical echogenicity was compared to that of the liver and spleen.

RESULTS

On the right side the increase in average inter-polar renal size was 2.5% at T30 and 2.6% at T60 (P < 0.05) compared to T0. On the left the increase was 3.8% at T30 and 4.3% at T60 (P < 0.05). Volume expansion for the right kidney was 16.8% at T30 and 14.0% at T60 (P < 0.05). On the left it was 12.9% at T30 and 10.2% at T60 (P < 0.05). Cortical echogenicity progressed from hypoechogenicity to isoechogenicity (P < 0.05). The percentage of expanded pelves increased with hydration (T0: 3.2%, T30: 9.7%, T60: 22.6%).

CONCLUSION

Oral hydration influences renal length, volume and echogenicity in children. Hydration results in expansion of the pelvis. We recommend standardisation of hydration before US examination.

Magnetic resonance and computed tomography in pediatric urology: an imaging overview for current and future daily practice

The main imaging modality of the urinary tract in children is ultrasound. When further cross-sectional morphologic examination and/or functional evaluation is required, magnetic resonance (MR) imaging is the logical and optimal second step, particularly in pediatric patients. There are two main exceptions to this. The first one is when after an ultrasound, additional diagnostic imaging for urolithiasis is needed. The second one involves severe polytrauma, including blunt abdominal trauma. In this review, an overview of the MR imaging and computed tomography examinations important for current and future daily pediatric uroradiologic practice is presented.

Acoustic radiation force impulse (ARFI) in the evaluation of the renal parenchymal stiffness in paediatric patients with vesicoureteral reflux: preliminary results

OBJECTIVES

To prospectively evaluate acoustic radiation force impulse (ARFI) imaging of the kidneys in children with and without chronic renal disease.

METHODS

Twenty-eight children (age range 9-16 years) with primary or secondary vesicoureteral reflux (≥ grade III) underwent scintigraphy and ultrasound with ARFI. Kidneys were divided-according to scintigraphy-into "affected" and "contralateral"; the results were compared with 16 age-matched healthy subjects. An ARFI value, expressed as speed (m/s) of wave propagation through the tissue, was calculated for each kidney through the mean of the values obtained at the upper, middle and lower third. The Wilcoxon test was used; P values <0.05 were considered statistically significant.

RESULTS

The mean ARFI values obtained in the "affected" kidneys (5.70 ± 1.71 m/s) were significantly higher than those measured in both "contralateral" (4.09 ± 0.97, P < 0.0001) and "healthy" kidneys (3.13 ± 0.09, P < 0.0001). The difference between values in the "contralateral" kidneys and "healthy" ones was significant (P < 0.0001). The "affected" kidneys with secondary reflux had mean ARFI values (6.59 ± 1.45) significantly higher than those with primary reflux (5.35 ± 1.72).

CONCLUSIONS

ARFI values decrease from kidneys with secondary vesicoureteral reflux to kidneys with primary reflux to unaffected kidneys contralateral to reflux to normal kidneys.

Multi-detector CT in the paediatric urinary tract

The use of paediatric multi-slice CT (MSCT) is rapidly increasing worldwide. As technology advances its application in paediatric care is constantly expanding with an increasing need for radiation dose control and appropriate utilization. Recommendations on how and when to use CT for assessment of the paediatric urinary tract appear to be an important issue. Therefore the European Society of Paediatric Radiology (ESPR) uroradiology task force and European Society of Urogenital Radiology (ESUR) paediatric working groups created a proposal for performing renal CT in children that has recently been published. The objective of this paper is to discuss paediatric urinary tract CT (uro-CT) in more detail and depth. The specific aim is not only to offer general recommendations on clinical indications and optimization processes of paediatric CT examination, but also to address various childhood characteristics and phenomena that facilitate understanding the different approach and use of uro-CT in children compared to adults. According to ALARA principles, paediatric uro-CT should only be considered for selected indications provided high-level comprehensive US is not conclusive and alternative non-ionizing techniques such as MR are not available or appropriate. Optimization of paediatric uro-CT protocols (considering lower age-adapted kV and mAs) is mandatory, and the number of phases and acquisition series should be kept as few as possible.

CT in children--dose protection and general considerations when planning a CT in a child

Today CT represents about 10% of all ionizing radiation based imaging modalities, but delivers more than 50% of the total collective dose for diagnostic imaging. Compared to adults the radiation sensitivity of children is considerable higher than in adults. Additionally children differ from adults--factors like body size, mass, density, proportions as well as metabolism have to be mentioned. Children grow and mature--all this components have to be mapped in examination protocols by Pediatric Radiology. The total dose of a CT examination depends on the settings of several factors such as the scout view, the scan length, exposure settings including automated exposure control, type of scanning (single slice, helical, volume mode), slice thickness, pitch values as well as on image reconstruction parameters. If intravenous contrast media injection is needed bolus tracking or timing represents another source of radiation. The aim of the paper is to present and discuss all aspects of defining a pediatric age and query adapted CT protocol particularly concerning all dose relevant factors in pediatric CT and their adjustment in children. Moreover hints are given concerning optimization of intravenous contrast media injection as well as special (low dose) imaging protocols.

MR imaging of the abdomen and pelvis in infants, children, and adolescents

Recent developments in magnetic resonance (MR) imaging have profoundly changed the investigation of abdominal and pelvic disease in pediatrics. Motion reduction techniques, such periodically rotated overlapping parallel lines with enhanced reconstruction, or PROPELLER, have resulted in reliable imaging with quiet breathing. Faster imaging sequences minimize artifact and allow for more efficient studies. Diffusion-weighted imaging has become increasingly important in the evaluation of neoplastic disease, depicting disease with increased cellularity and helping to differentiate benign from malignant masses. MR enterography helps visualize intra- and extraluminal bowel pathologic conditions. MR cholangiopancreatography can depict congenital and acquired causes of pancreatic and biliary abnormalities. MR urography is an effective technique for a one-stop-shop evaluation of structural urinary tract abnormality and renal function. Three-dimensional acquisitions allow volumetric display of structures from multiple angles. Specialized techniques allow quantification of iron and fat in the viscera in children with hemolytic anemia and obesity, respectively. This article covers current techniques and strategies to perform and optimize MR imaging of the abdomen and pelvis in infants, children, and adolescents and describes important practical applications.