Patient dose reduction during voiding cystourethrography

[Voiding cystourethrography : Indications, fluoroscopy technique and radiation protection]

BACKGROUND

Voiding cystourethrography continues to be the gold standard in the diagnostics of a wide range of diseases of the urinary tract in children.

MATERIAL AND METHODS

Indications, implementation of voiding cystourethrography in terms of preparation, materials used, dealing with the child and the parents as well as the standardized examination technique are presented. In particular, the technical aspects of fluoroscopy devices and criteria for good image quality are discussed. Case studies are used to illustrate the problems of frequent urological diseases.

DISCUSSION

The three standard examinations for the detection of vesicoureteral reflux (VUR), radionuclide cystography, contrast-enhanced voiding urosonography and voiding cystourethrography are compared. Their potential for detecting VUR and additional urological pathologies is discussed in detail. Furthermore, the optimized examination technique of voiding cystourethrography is presented. The applicability of the current dose reference values of the German Federal Office for Radiation Protection (BfS) in the daily routine is discussed and the feasibility of the dose reference values is explained.

Radiation exposure to infants undergoing voiding cystourethrography: The importance of the digital imaging technology

PURPOSE

To determine the radiation burden to infants undergoing voiding cystourethrography (VCUG) in a single institution and investigate the effect of shifting from analogue to digital imaging that allowed the use of a radiography-free examination protocol.

METHODS

Anthropometric and exposure data were prospectively collected for 35 consecutive infants undergoing VCUG on a digital system with a standardized examination protocol not including radiographs. Thermoluminescent dosimeters were used to determine entrance-skin dose. Monte Carlo simulations and patient-specific anthropomorphic phantoms were employed to determine organ/tissue doses and effective dose (ED). The associated theoretical risk of radiation-induced cancer was determined and compared to the nominal risk of cancer induction. The radiation burden from VCUG on a modern digital system with a contemporary examination protocol was compared to corresponding data reported previously for an analogue system in the same institution.

RESULTS

The median ED from VCUG was found 47 μSv. The associated total life attributable risk of radiation-induced cancer was found 10x10^-6 and 13x10^-6 for boys and girls, respectively. VCUG was found to increase the nominal risk of cancer by a factor of 1.000025 in boys and 1.000034 in girls. Shifting from analogue to digital imaging system resulted in 89% reduction of the radiation burden from VCUG.

CONCLUSION

The theoretical radiation risks for infants undergoing VCUG using a modern digital imaging system and a radiography-free protocol were found to be minor. The transition from analogue to digital equipment resulted in considerable reduction of the radiation burden from VCUG.

Contrast-enhanced voiding urosonography in the diagnosis of intrarenal reflux

PURPOSE

Although contrast-enhanced urosonography (ceVUS) has shown capable diagnostic accuracy for the diagnosis of vesicoureteral reflux (VUR) in children, the ability of ceVUS to detect intrarenal reflux (IRR) is considered limited. The purpose of our study is to assess the ability of ceVUS to detect IRR as well as its association with age, gender, and the grade of VUR.

METHODS

This study included 5153 children who were referred to our clinic for ceVUS. All children underwent sonographic examinations, which were performed on a LOGIQ S8 machine equipped with dedicated software for contrast-enhanced studies with harmonic imaging. Standard ultrasound of the urinary tract was followed by bladder catheterisation and instillation of physiological normal saline and the US contrast medium (SonoVue^®, Bracco).

RESULTS

VUR was diagnosed by ceVUS in 1959 out of 5153 children (38%), of whom IRR was found in 233 of 1959 children (11.9%). A total of 285 ureteral units showing IRR were found. High grades of VUR (IV + V) with IRR were found in a total of 235 of 285 (82.81%) renal units. Bilateral IRR was found in 53 patients, usually with a high-grade VUR on both sides. Most children had VUR grade IV, predominantly those < 12 months. The younger the child, the higher the likelihood of higher-grade VUR (p = 0.02).

CONCLUSION

ceVUS, combined with harmonic imaging and second-generation ultrasound contrast media, enabled IRR detection in almost 12% of our patients with VUR. IRR is most commonly found in children under 1 year of age with VUR grades IV and V.

Postnatal management of children with antenatal hydronephrosis

Background

Postnatal management of infants with antenatal hydronephrosis (ANH) is still one of the most controversial issues. The majority of infants with ANH are asymptomatic with only few children who develop renal insufficiency. Thus, the biggest challenge for pediatric urologists is to distinguish children who will require further investigations and possible intervention prior to the development of symptoms, complications or renal damage in a cost effective manner without exposing them to the hazards of unnecessary investigations.

Main body

In this review article, literature on ANH were reviewed to present the current suggestions, recommendations, guidelines and their rational for postnatal management of ANH. It is agreed that a large portion of infants with ANH will improve; thus, the protocol of management is based mainly on observation and follow-up by ultrasound to detect either resolution, stabilization or worsening of hydronephrosis. The first 2 years of life are critical for this follow-up as the final picture is mostly reached during that period. Advanced imaging using voiding cystourethrography or renal scintigraphy are required for children at risk. Then, surgical intervention is selected only for a subgroup of these infants who showed worsening of hydronephrosis or renal function.

Conclusions

The protocol of management is based mainly on observation and follow-up by US to detect either resolution, stabilization or worsening of hydronephrosis. Postnatal evaluation should be performed for any neonate with a history ANH at any stage during pregnancy even if it was resolved during third trimester. Exclusion of UTI should be performed by urinalysis for all cases followed by urine culture if indicated. Serum creatinine should be performed especially in patients with bilateral ANH. US is the initial standard diagnostic imaging technique. Other imaging modalities like VCUG and nuclear renal scans may be required according to the results of the US evaluation. The most important items in decision making are the presence of bilateral or unilateral hydronephrosis, presence or absence of hydroureter, presence of lower urinary tract obstruction and degree of hydronephrosis on the initial postnatal US. Then an intervention is selected only for a subgroup of these patients who showed deterioration in renal function or degree of hydronephrosis or were complicated by UTIs. All these recommendations are based on the available literature. However, management of ANH is still a controversial issue due to lack of high evidence-based recommendations. Randomised controlled studies are still needed to provide a high level evidence for different aspects of management.

The ABCs of Voiding Cystourethrography

Voiding cystourethrography (VCUG) demonstrates the anatomy of the urinary system and is used to detect the presence/absence of vesicoureteral reflux. It is the most important modality for urological fluoroscopic examination in children. For improved patient care, it is important to understand and perform VCUG appropriately. Therefore, an in-depth review of VCUG protocols and techniques has been presented herein. In addition, tips, tricks, and pitfalls associated with the technique have also been addressed.

Effect of using immobilization device in fluoroscopic study in pediatric patient: Focused on radiation dose reduction in voiding cystourethrogram

Introduction

To prove objective effect of using mechanical device for immobilization of pediatric patient during voiding cystourethrogram (VCUG) compare immobilization by hand-holding.

Methods

This study included 77 patients, who underwent VCUG in our center from April to October 2017, who had a clinically suspicious urinary tract infection. Patients were classified into one of two groups based on whether examination was done before (Group A) or after (Group B) adaptation of immobilization device. Patient-related data, image quality related score and dose-related data were collected and compared between two groups.

Results

Group A included 36 patients and group B included 41. Patient related data including mean age, sex, body weight and height didn’t show significant difference between two groups (p > 0.05 for all). Among the image quality scoring, overall image quality, motion artifact, showed significant difference between two groups with improved inadequate timing and centering after adaptation of immobilization device. Dose related data showed significantly decreased shot number, mean fluoroscopic time with decreased mean dose area product (DAP) value and effective dose after adaptation of immobilization device (p < 0.05 for all).

Conclusion

Adaptation of immobilization device can improve overall image quality with decreased motion artifact and improved centering and timing with even shot number, mean fluoroscopic time with decreased mean DAP value and effective dose.

Pediatric voiding cystourethrography: An essential examination for urologists but a terrible experience for children

Voiding cystourethrography is the most important fluoroscopic examination in pediatric urology for the investigation of lower urogenital tract diseases, such as vesicoureteral reflux or urethral stricture. However, this invasive procedure imposes a significant burden on children and their parents, and recently there has been a paradigm shift in the diagnosis and treatment of vesicoureteral reflux. In the 2011 revision, the American Academy of Pediatrics guidelines on urinary tract infection recommended abandoning routine voiding cystourethrography after the first febrile urinary tract infection. In 2014, the randomized intervention for children with vesicoureteral reflux study recommended discontinuation of routine continuous antibiotic prophylaxis for vesicoureteral reflux. The time is now ripe to radically reconsider indications for voiding cystourethrography and the procedure itself.

Is the Scout Out? The Utility of Scout Radiographs in the Pediatric Upper Gastrointestinal Examination

OBJECTIVE

The aim of the study is to demonstrate the scout radiograph does not change patient management, alter planning, or contribute to interpretation of the outpatient pediatric upper gastrointestinal fluoroscopic examination (UGI).

METHODS

We retrospectively reviewed 197 outpatient pediatric UGIs performed over a 2-year period. We performed a chart review on all patients to evaluate for potentially clinically significant findings on the scout radiograph. Scout findings were categorized into 4 groups: no new clinically significant findings (group 1), potentially clinically significant findings that were not directly addressed in the electronic medical record (group 2), incidental non-gastrointestinal (GI) findings that necessitated further workup, however, were later deemed insignificant (group 3), and clinically significant findings that changed patient GI management, altered the planning of the procedure, or contributed to the interpretation of the fluoroscopic study (group 4).

RESULTS

A total of 197 UGIs were analyzed. A significant majority of cases (97.0%) were classified into group 1. Three cases (1.5%) were classified into group 2 with findings not addressed in the medical record. Two cases (1.0%) were classified into group 3, which, after further workup, were deemed not clinically significant. One case (0.5%) was classified into group 4, which resulted in a change in patient GI management.

CONCLUSIONS

In our review, there was only 1 case in which the scout radiograph changed patient GI management, with moderate stool burden leading to a miralax cleanout, although there were no cases, which altered the planning of the procedure or contributed to the interpretation of the study. The scout radiograph can be omitted and/or substituted with the last image hold function to decrease radiation exposure.

Running water sound technique in contrast-based voiding cystourethrogram: A case-control study

BACKGROUND

An intervention that can reduce the patient void time during a voiding cystourethrogram (VCUG) procedure can reduce the total radiation dose to the patient. This is because a delay in voiding leads to a high number of intermittent screenings to monitor if voiding occurs. This study assessed the impact of running-water sound (RWS) upon patients' voiding parameters and fluoroscopy screening times during VCUG examinations among children and adults.

MATERIALS AND METHODS

A case-control study involving 252 patients was undertaken which consisted two groups (control and test) of adults and children. The test groups underwent VCUG with RWS technique while the control groups underwent the procedure normally. T-test was used to compare the study parameters between the two groups and a p-value less than 0.05 was interpreted as significant.

RESULTS

The mean screening times (s) for children who underwent VCUG with and without RWS were 17.15 ± 2.5s and 30.61 ± 5.1s respectively (p = 0.0024). For adults, the RWS technique recorded a mean screening time of 37.36 ± 4.4s while the non-RWS procedures recorded 49.80 ± 5.2s (p = 0.001). The participants who received RWS intervention also felt the urge to void earlier than those who received no RWS intervention. The differences were also statistically significant for both children and adults.

CONCLUSION

The study being one of the first in this subject area indicates that the application of RWS technique induces early urge of iodinated-contrast voiding, and reduces voiding and fluoroscopy screening times during VCUG among children and adults. This simple technique can potentially enhance current practice.

Pre-procedural scout radiographs are unnecessary for routine pediatric fluoroscopic examinations

BACKGROUND

Although practice patterns vary, scout radiographs are often routinely performed with pediatric fluoroscopic studies. However few studies have evaluated their utility in routine pediatric fluoroscopy.

OBJECTIVE

To evaluate the value of scout abdomen radiographs in routine barium or water-soluble enema, upper gastrointestinal (GI) series, and voiding cystourethrogram pediatric fluoroscopic procedures.

MATERIALS AND METHODS

We retrospectively evaluated 723 barium or water-soluble enema, upper GI series, and voiding cystourethrogram fluoroscopic procedures performed at our institution. We assessed patient history and demographics, clinical indication for the examination, prior imaging findings and impressions, scout radiograph findings, additional findings provided by the scout radiograph that were previously unknown, and whether the scout radiograph contributed any findings that significantly changed management.

RESULTS

We retrospectively evaluated 723 fluoroscopic studies (368 males and 355 females) in pediatric patients. Of these, 700 (96.8%) had a preliminary scout radiograph. Twenty-three (3.2%) had a same-day radiograph substituted as a scout radiograph. Preliminary scout abdomen radiographs/same-day radiographs showed no new significant findings in 719 (99.4%) studies. New but clinically insignificant findings were seen in 4 (0.6%) studies and included umbilical hernia, inguinal hernia and hip dysplasia. No findings were found on the scout radiographs that would either alter the examination performed or change management with regard to the exam.

CONCLUSION

Pre-procedural scout abdomen radiographs are unnecessary in routine barium and water-soluble enema, upper GI series, and voiding cystourethrogram pediatric fluoroscopic procedures and can be substituted with a spot fluoroscopic last-image hold.

Radiation exposure contribution of the scout abdomen radiograph in common pediatric fluoroscopic procedures

BACKGROUND

Contrast enema, voiding cystourethrography and upper gastrointestinal studies are the most common fluoroscopic procedures in children. Scout abdomen radiographs have been routinely obtained prior to fluoroscopy and add to the radiation exposure from these procedures. Elimination of unnecessary routine scout radiographs in select studies might significantly reduce radiation exposure to children and improve the overall benefit-to-risk ratio of these fluoroscopic procedures.

OBJECTIVE

To determine the radiation exposure contribution of the preliminary/scout abdomen radiographs with respect to the radiation exposure of the total procedure.

MATERIALS AND METHODS

We retrospectively collected demographic information and radiation exposure values of dose area product (in Gy-cm(2)) and entrance air kerma (in mGy) - initially for the scout abdomen radiographs done prior to fluoroscopy and subsequently the total procedural radiation values (the combined values of the scout radiograph and fluoroscopic radiation exposure) - in children who underwent contrast enemas, voiding cystourethrograms and upper gastrointestinal studies in a 4-month period. The radiation parameters, including fluoroscopy time, dose area product and entrance air kerma, were available in the log book maintained in the fluoroscopy suite. Fluoroscopy procedures were performed on a single fluoroscopy machine using four frames per second pulse rate and other radiation-minimizing techniques. Usage of the grid to obtain scout radiographs was also recorded. The proportion of radiation exposure from the scout radiograph relative to that of the total procedure was calculated by dividing the individual parameters of the scout to the total procedural values and multiplied by 100 to express these values as a percentage. We calculated mean, median and range and performed statistical analysis of the data.

RESULTS

A total of 151 procedures performed on 71 males and 80 females qualified for the study. The age range of the patients was 2 days to 18 years, with a mean of nearly 3.5 years (40 months) and median of 15 months. There were 63 upper gastrointestinal studies, 65 voiding cystourethrography studies and 23 contrast enema studies. The fluoroscopy time for all procedures combined ranged from 0.1 min (6 s) to 2 min, with mean and median values of 0.4 min and 0.3 min, respectively. The fractional radiation exposure contribution for the dose area product of scout abdomen radiograph to the total procedure ranged from 4% to 98%, with mean and median values of 51% and 49%, respectively. The fractional contribution of the scout radiograph to the total procedure for the entrance air kerma values ranged from 6% to 97%, with mean and median values of 29% and 26%, respectively. There was a significant negative correlation (P<0.001) between fluoroscopy radiation time and the proportion of radiation parameters of scout radiograph to total procedural values.

CONCLUSION

Scout radiographs can contribute a significant proportion (median values of approximately 50% for the dose area product and 26% for the entrance air kerma) of radiation exposure in common fluoroscopy procedures in children.

Reducing Radiation Dose in Pediatric Diagnostic Fluoroscopy

PURPOSE

To assess radiation dose in common pediatric diagnostic fluoroscopy procedures and determine the efficacy of dose tracking and dose reduction training to reduce radiation use.

METHODS

Fluoroscopy time and radiation dose area product (DAP) were recorded for upper GIs (UGI), voiding cystourethrograms (VCUGs), and barium enemas (BEs) during a six-month period. The results were presented to radiologists followed by a 1-hour training session on radiation dose reduction methods. Data were recorded for an additional six months. DAP was normalized to fluoroscopy time, and Wilcoxon testing was used to assess for differences between groups.

RESULTS

Data from 1,479 cases (945 pretraining and 530 post-training) from 9 radiologists were collected. No statistically significant difference was found in patient age, proportion of examination types, or fluoroscopy time between the pre- and post-training groups (P ≥ .1), with the exception of a small decrease in median fluoroscopy time for VCUGs (1.0 vs 0.9 minutes, P = .04). For all examination types, a statistically significant decrease was found in the median normalized DAP (P < .05) between pre- and post-training groups. The median (quartiles) for pretraining and post-training normalized DAPs (μGy·m(2) per minute) were 14.36 (5.00, 38.95) and 6.67 (2.67, 17.09) for UGIs; 13.00 (5.34, 32.71) and 7.16 (2.73, 19.85) for VCUGs; and 33.14 (9.80, 85.26) and 17.55 (7.96, 46.31) for BEs.

CONCLUSIONS

Radiation dose tracking with feedback, paired with dose reduction training, can reduce radiation dose during diagnostic pediatric fluoroscopic procedures by nearly 50%.

Evaluation of pediatric VCUG at an academic children's hospital: is the radiographic scout image necessary?

BACKGROUND

There is heterogeneity in how pediatric voiding cystourethrography (VCUG) is performed. Some institutions, including our own, obtain a radiographic scout image prior to contrast agent instillation.

OBJECTIVE

To demonstrate that the radiographic scout image does not augment VCUG interpretation or contribute management-changing information but nonetheless carries a non-negligible effective dose.

MATERIALS AND METHODS

We evaluated 181 children who underwent VCUG in 2012, with an age breakdown of less than 1 year (56 children), 1-5 years (66 children), 6-10 years (43 children) and 11-18 years (16 children), with a mean age of 4.0 years. We investigated patient demographics, clinical indication for the examination, scout image findings and estimated effective radiation dose, as well as overall exam findings and impression.

RESULTS

No clinically significant or management-changing findings were present on scout images, and no radiopaque urinary tract calculi or concerning incidental finding was identified. Scout image estimated effective radiation dose averaged 0.09 mSv in children younger than 1 y, 0.09 mSv in children age 1-5, 0.13 mSv in children age 6-10 and 0.18 mSv in children age 11-18. Total fluoroscopy time per examination averaged 36.7 s (range 34.8-39.6 s for all age group averages). Evaluation of known or suspected vesicoureteral reflux (VUR) and urinary tract infection (UTI) were the most common clinical indications, stated in 40.9% and 37.0% of exams, respectively.

CONCLUSION

Although the estimated effective dose is low for VCUG radiographic scout images, this step did not augment VCUG interpretation or contribute management-changing information. This step should be omitted or substituted to further reduce dose in pediatric VCUG.

Implementation of a competency check-off in diagnostic fluoroscopy for radiology trainees: impact on reducing radiation for three common fluoroscopic exams in children

BACKGROUND

Fluoroscopy is an important tool for diagnosis in the pediatric population, but it carries the risk of radiation exposure. Because radiology resident education and experience in the use of fluoroscopy equipment in children vary, we implemented an intervention to standardize fluoroscopy training.

OBJECTIVE

The purpose of this study is to determine the impact of implementing a fluoroscopy competency check-off for radiology resident trainees aimed at decreasing radiation exposure in three common pediatric fluoroscopic studies.

MATERIALS AND METHODS

A fluoroscopy competency check-off form was developed for radiology resident trainees performing pediatric procedures. Techniques used to limit radiation exposure for common pediatric radiologic studies were reviewed as part of the check-off process. Pediatric radiologists supervised each trainee until they demonstrated competence to independently perform three specified procedures. Radiation dose was recorded for the three procedures, upper GI (UGI), voiding cystourethrogram (VCUG) and oropharyngeal (OPM) exams, over 6 months preceding and 6 months following implementation of the competency check-off. The mean cumulative dose for each procedure was compared before and after implementation of competency check-off using a Kruskal-Wallis test.

RESULTS

During the 12-month study period doses from 909 fluoroscopic procedures were recorded. In the 6 months preceding competency check-off implementation, procedures were performed by 24 radiology resident trainees including 171 UGI, 176 VCUG and 171 OPM exams. In the 6 months following competency check-off, 23 trainees performed 114 UGI, 145 VCUG and 132 OPM exams. After competency check-off implementation, a statistically significant reduction in average radiation dose was found for all three studies (P < 0.001). Median cumulative doses (mGy) were decreased by 33%, 36% and 13% for UGIs, VCUGs and OPMs, respectively.

CONCLUSION

Implementation of a competency check-off for radiology resident trainees can reduce average radiation doses in pediatric patients undergoing three common fluoroscopic studies.

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.

Subsequent cancer risk of children receiving post voiding cystourethrography: a nationwide population-based retrospective cohort study

BACKGROUND

To estimate the subsequent cancer risk of children receiving post voiding cystourethrography (VCUG), a nationwide population-based retrospective cohort study with the data from the Taiwan National Health Insurance Research Database (NHIRD) were used for the analysis.

METHODS

In the VCUG cohort, 31,908 participants younger than 18 years of age who underwent VCUG between 1997 and 2008 were identified from the NHIRD. A comparison cohort, the non-VCUG cohort, was randomly selected among children without VCUG examination histories during 1997-2008, frequency matched for age (every 5 years), sex, geographic region area, parents' occupation, and index year based on a 1:4 ratio. Cox's proportional hazard regression analysis was conducted to estimate the subsequent cancer risk of children receiving VCUG.

RESULTS

The overall cancer risk of the VCUG cohort is 1.92-fold (95 % CI = 1.34-2.74) higher than that of the non-VCUG cohort with statistical significance. The genital cancer and urinary system cancer risks of the VCUG cohort are respectively 6.19-fold (95 % CI = 1.37-28.0) and 5.8-fold (95 % CI = 1.54-21.9) higher than those of the non-VCUG cohort with statistical significance. The hazard ratios are higher in genital cancer, urinary system cancer (the major radiation exposure area), and cancer of the abdomen, except for the genitourinary system (the minor radiation exposure area), in sequence.

CONCLUSIONS

Pediatric VCUG is associated with increased subsequent cancer risk, especially in the genitourinary system.

Nonionizing photoacoustic cystography with near-infrared absorbing gold nanostructures as optical-opaque tracers

AIM

The objectives of this study were to demonstrate nonionizing photoacoustic tomography (PAT) of bladders with near-infrared absorbing gold nanocages (GNCs) as an optical-turbid tracer and to investigate the fate of GNCs after photoacoustic imaging.

MATERIALS & METHODS

The rats' bladders were visualized using PAT after transurethral injection of 2-nM GNCs. The fate of GNCs in the bladders was investigated. Spectroscopic PAT was applied to identify GNC-filled bladders in vivo and study biodistribution ex vivo.

RESULTS

Rats' bladders filled with GNCs were successfully imaged using a PAT system. The photoacoustic amplitude was enhanced by approximately 2240%. Both in vivo and ex vivo PAT results reveal that no accumulation of GNCs in the bladder and kidney was observed, and were validated with inductively coupled plasma mass spectrometry.

CONCLUSION

The PAT with transurethral injection of GNCs provides two crucial safety features for clinical translation: no radiation exposure and no long-term heavy metal accumulation.

Comparison between patient dose arising from photofluorographic and standard fluoroscopic voiding cystourethro graphy in children with urinary tract infection [corrected]

BACKGROUND

Imaging of the urinary system is considered to be responsible for significant radiation in children.

OBJECTIVES

This study was conducted to measure and compare the radiation dose in spot films with photofluorography voiding cystourethrography (VCUG) in children.

PATIENTS AND METHODS

111 [222 Kidney Urinary Unit (KUU)] pediatric patients, aged 1 month to 5 years, with symptomatic urinary tract infection were enrolled in the study. Peak tube voltage (kVp), exposure setting (mAs), focus film distance (FFD), film size and DAP (after the exam) were recorded for all patients. To evaluate the validity of the photographs, we calculated sensitivity, specificity, predictive values and agreement between the two methods using the kappa statistic. If the kappa was greater than 0.75, between 0.4-0.75 or less than 0.4, then the agreement was excellent, good or poor, respectively. P values less than 0.05 were statistically significant.

RESULTS

Vesicoureteral reflux (VUR) was detected in 74 KUU (33.3%) in standard films and in 71 (32%) in photographic images. The photographs had no false positives and 3 false negatives. Therefore, the new method had a sensitivity of 96%, a specificity of 100%, a negative predictive value of 98% and a positive predictive value of 100%. The two-method agreement in the VUR diagnosis for grades 1, 4, 5 and the overall grading were excellent (kappa > 0.83); however, for grades 2 and 3, agreement was 80%, which was good (kappa = 0.64).

CONCLUSIONS

Our study suggests that the high validity and excellent agreement of the photofluorography method in the diagnosis and grading of VUR, which is comparable to spot films and represents a 50%-90% reduction in radiation, makes it the preferred method.

Revised guidelines on management of antenatal hydronephrosis

Widespread antenatal screening has resulted in increased detection of anomalies of the kidneys and urinary tract. The present guidelines update the recommendations published in 2000. Antenatal hydronephrosis (ANH) is transient and resolves by the third trimester in almost one-half cases. The presence of oligohydramnios and additional renal or extrarenal anomalies suggests significant pathology. All patients with ANH should undergo postnatal ultrasonography; the intensity of subsequent evaluation depends on anteroposterior diameter (APD) of the renal pelvis and/or Society for Fetal Urology (SFU) grading. Patients with postnatal APD exceeding 10 mm and/or SFU grade 3-4 should be screened for upper or lower urinary tract obstruction and vesicoureteric reflux (VUR). Infants with VUR should receive antibiotic prophylaxis through the first year of life, and their parents counseled regarding the risk of urinary tract infections. The management of patients with pelviureteric junction or vesicoureteric junction obstruction depends on clinical features and results of sequential ultrasonography and radionuclide renography. Surgery is considered in patients with increasing renal pelvic APD and/or an obstructed renogram with differential renal function <35-40% or its subsequent decline. Further studies are necessary to clarify the role of prenatal intervention, frequency of follow-up investigations and indications for surgery in these patients.

Last fluoroscopy hold in paediatric fluoroscopy: dynamic capture of physiological events and a potential for radiation exposure time reduction

The purpose of this study was to retrospectively evaluate last fluoroscopy hold (LFH) in paediatric fluoroscopy. LFH is a software program that enables dynamic storage of last fluoroscopy sequences. A hundred and ninety-four paediatric patients underwent 215 fluoroscopy examinations during a 14-month period. LFH was employed to review an equivocal finding, when last image hold did not provide an adequate diagnostic image or when a physiologic dynamic event was too fast or did not last long enough to capture. LFH was used in 29% of the examinations. The Institutional Review Board approved this study and waived informed consent.

Economic and radiation costs of initial imaging approaches after a child's first febrile urinary tract infection

BACKGROUND. The traditional initial imaging approach following pediatric urinary tract infection is the "bottom-up" approach (cystogram and renal ultrasound). Recently, the "top-down" approach (nuclear renal scan followed by cystogram for abnormal scans only) has gained increasing attention. The relative cost and radiation doses of these are unknown METHODS. The authors used a decision model to evaluate these imaging approaches. Cost and effective radiation dose estimates, including sensitivity analyses, were based on one-time imaging only. RESULTS. Comparing hypothetical cohorts of 100 000 children, the top-down imaging approach cost $82.9 million versus $59.2 million for the bottom-up approach. Per-capita effective radiation dose was 0.72 mSv for top-down compared with 0.06 mSv for bottom-up. CONCLUSIONS. Routine use of nuclear renal scans in children following initial urinary tract infection diagnosis would result in increased imaging costs and radiation doses as compared to initial cystogram and ultrasound. Further data are required to clarify the long-term clinical implications of this increase.

Pause and pulse: ten steps that help manage radiation dose during pediatric fluoroscopy

OBJECTIVE

The Image Gently Campaign of The Alliance for Radiation Safety in Pediatric Imaging seeks to increase awareness of opportunities to lower radiation dose in the imaging of children. Pause and Pulse is the most recent phase of the campaign, addressing methods of dose optimization in pediatric fluoroscopy.

CONCLUSION

This article discusses 10 steps that can be taken for fluoroscopic dose optimization in pediatric diagnostic fluoroscopy.

Urinary tract infection: clinical practice guideline for the diagnosis and management of the initial UTI in febrile infants and children 2 to 24 months

OBJECTIVE

To revise the American Academy of Pediatrics practice parameter regarding the diagnosis and management of initial urinary tract infections (UTIs) in febrile infants and young children.

METHODS

Analysis of the medical literature published since the last version of the guideline was supplemented by analysis of data provided by authors of recent publications. The strength of evidence supporting each recommendation and the strength of the recommendation were assessed and graded.

RESULTS

Diagnosis is made on the basis of the presence of both pyuria and at least 50,000 colonies per mL of a single uropathogenic organism in an appropriately collected specimen of urine. After 7 to 14 days of antimicrobial treatment, close clinical follow-up monitoring should be maintained to permit prompt diagnosis and treatment of recurrent infections. Ultrasonography of the kidneys and bladder should be performed to detect anatomic abnormalities. Data from the most recent 6 studies do not support the use of antimicrobial prophylaxis to prevent febrile recurrent UTI in infants without vesicoureteral reflux (VUR) or with grade I to IV VUR. Therefore, a voiding cystourethrography (VCUG) is not recommended routinely after the first UTI; VCUG is indicated if renal and bladder ultrasonography reveals hydronephrosis, scarring, or other findings that would suggest either high-grade VUR or obstructive uropathy and in other atypical or complex clinical circumstances. VCUG should also be performed if there is a recurrence of a febrile UTI. The recommendations in this guideline do not indicate an exclusive course of treatment or serve as a standard of care; variations may be appropriate. Recommendations about antimicrobial prophylaxis and implications for performance of VCUG are based on currently available evidence. As with all American Academy of Pediatrics clinical guidelines, the recommendations will be reviewed routinely and incorporate new evidence, such as data from the Randomized Intervention for Children With Vesicoureteral Reflux (RIVUR) study.

CONCLUSIONS

Changes in this revision include criteria for the diagnosis of UTI and recommendations for imaging.

Pediatric uroradiology: state of the art

Recent years have witnessed major strides in imaging modalities, including US and contrast-enhanced voiding urosonography, fluoroscopy, CT and MRI, and these have significantly impacted paediatric uroradiology. The trend is towards reduced or no radiation exposure and combined morphological and functional imaging. This review presents the currently available and recommended modalities in modern paediatric uroradiology practice.

The efficacy of digital fluoroscopic image capture in the evaluation of vesicoureteral reflux in children

BACKGROUND

In accordance with ALARA, minimizing radiation exposure associated with voiding cystourethrograms (VCUG) is of critical importance. Advances in fluoroscopic technology might help achieve this goal.

OBJECTIVE

To determine the efficacy of fluoroscopic image capture compared to conventional digital radiographic spot (DRS) images in voiding cystourethrograms (VCUG) for the evaluation of vesicoureteral reflux (VUR) in children.

MATERIALS AND METHODS

The study was a retrospective review of 65 VCUG examinations (130 kidney/ureter units). Each examination consisted of fluoroscopically captured spot (FCS) images and the corresponding DRS images. Each set of images was evaluated by three pediatric radiologists for the diagnosis of VUR for a total of 390 kidney/ureter units reviewed. Using the DRS image set as the reference standard, the efficacy of the FCS images for diagnosing reflux was determined.

RESULTS

The diagnostic accuracy of the FCS images in terms of the binary characterization of reflux as negative or positive was 97.2% (379/390). The sensitivity of the FCS images was 92.6% (88/95); the specificity of the FCS images was 98.6% (291/295).

CONCLUSION

Fluoroscopically captured images are adequate in documenting absence of VUR on VCUG examinations, obviating the need for radiographic spot images and resulting in reduction in radiation exposure.

Avaliação das doses de radiação em uretrocistografia miccional de crianças

OBJETIVO: Analisar o produto dose-área, a dose de entrada na pele do paciente e as doses relativas à fluoroscopia e às radiografias em exames de cistouretrografia miccional em crianças. MATERIAIS E MÉTODOS: Foram avaliados os procedimentos em 37 pacientes, realizados por quatro médicos do serviço. As medições foram realizadas com um equipamento composto de uma câmara de ionização acoplada diretamente à saída do tubo de raios X e um eletrômetro (Diamentor) ligado diretamente ao computador, para a coleta dos dados. RESULTADOS: Foi observada alguma heterogeneidade na realização do procedimento, que não segue padrão de técnica radiográfica. São realizadas em média 11 radiografias por exame, usando tempo longo de fluoroscopia, com dose média final mais alta que a encontrada em referências da literatura. CONCLUSÃO: A adoção da técnica de alta quilovoltagem nas radiografias e o uso restrito da fluoroscopia podem proporcionar importante redução das doses durante a realização deste procedimento, porque o maior contribuinte para as altas doses verificadas foi a utilização da fluoroscopia.

Radiation safety and future innovative diagnostic modalities

One must demand an accurate, safe, radiation-free, and noninvasive method for reflux examination as the ideal possibility for reflux screening. Of course the available different imaging modalities are far from this ideal situation, but minimal radiation exposure is indeed a permanent objective. Additionally since all of these studies might be quite stressful to the child and the family, a specially designed and equipped environment is obligatory for the comfort of all involved. An absolute ideal modality in the diagnosis of VUR would be the definition of a certain marker in serum or urine that could identify children with VUR without the need for any interventional screening modality. Therefore more and more efforts have to be made in the future to investigate different markers for this purpose. Since reflux is one of the most frequent congenital conditions pediatric urologist have to deal with potential risks that might lead to renal insufficiency, noninvasive and radiation-free modalities should become the methods of choice, hopefully in the near future.

Antenatally detected urinary tract abnormalities: more detection but less action

We present the findings of a prospective cohort study of babies born with antenatally detected urinary tract abnormalities (AUTAs) between 1999-2003 and compare the outcomes with those of an earlier cohort born between 1989 and 1993. All infants with a fetal anteroposterior renal pelvic diameter (APRPD) > or =7 mm in the third trimester or other urinary tract abnormality underwent a detailed postnatal ultrasound scan and other investigations as indicated. The incidence of AUTAs was significantly greater in the more recent cohort (7.6/1000 vs. 3/1000 live births; p<0.05). Of the 350 infants on which we had data, 48.6% (170/350) were in the non-specific dilatation (NSD) category, and vesicoureteric reflux (VUR) was detected in 12%. Restricting investigations to those who had an APRPD > or =10 mm at >30 weeks of gestation could have reduced the number with NSD in the more recent cohort (26/115; 25%), but 25% of those with pelviureteric junction hold-up and 50% with VUR would have been missed. Significantly fewer patients in the more recent cohort underwent surgery (7 vs. 21%; p<0.001). There is a trend towards larger APRPDs on third trimester scans being associated with more significant pathology, but there is a lot of clinical overlap. The study highlights the need for cautious antenatal counselling combined with an assurance to prospective parents that postnatal investigations will be performed in a stepwise manner based on the initial postnatal ultrasound scan and clinical findings.