Peri-surgical imaging of intersex and gender diverse youths

This publication provides an overview of current imaging indications and practices for patients undergoing gender-affirming surgery, with an emphasis on the importance of tailored, patient-specific care. Gender-affirming surgeries are performed with personalized approaches at various stages of life for those with intersex traits or differences in sex development (I/DSD) and transgender and gender diverse (TGD) individuals. For I/DSD patients, ultrasound, genitography, or MRI occurs during infancy and puberty to evaluate genital and gonadal anatomy. Facial harmonization involves bony and soft tissue modifications, guided by maxillofacial computerized tomography (CT) with three-dimensional reconstruction. Ultrasound is the main modality in assessing hormone-related and post-surgical changes in the chest. Imaging for genital reconstruction uses cross-sectional images and fluoroscopy to assess neoanatomy and complications.

Age-specific Dose Catalog for Diagnostic Fluoroscopy and Fluoroscopically Guided Interventional Procedures from a Pediatric Hospital

Background Fluoroscopy is an imaging modality associated with a wide range of dose levels, characterized using a variety of dose metrics, including effective dose. However, for clinical procedures, effective dose is a seldom-used and unregulated metric in the United States, and thus, it is not extensively studied in radiology despite potentially large clinical implications for patients, especially children and infants. Purpose To formulate and report a dose catalog across all diagnostic and interventional radiology (IR) fluoroscopy examination or procedure types at a specialized tertiary care pediatric hospital. Materials and Methods In this retrospective study, dose metrics taken from radiation dose structured reports of fluoroscopy between October 2014 and March 2023 were analyzed. The reports included fluoroscopy across 18 diagnostic examination types and 24 IR procedure types. The National Cancer Institute dosimetry system for Radiography and Fluoroscopy Monte Carlo software was used to estimate age-specific effective dose from dose-area product (DAP). The DAP-to-effective dose conversion factors were estimated per IR procedure type and diagnostic fluoroscopy examination type based on age. Results A total of 11 536 individual diagnostic fluoroscopy examinations (18 types) and 8017 individual IR procedures (24 types) were analyzed. Median effective dose values per diagnostic fluoroscopy examination type ranged from 0.0010 to 0.44 mSv (mean, 0.0808 mSv ± 0.0998 [SD]). Calculated DAP-to-effective dose conversion factors ranged from 0.04 to 2.48 mSv/Gy · cm2 (mean, 0.758 mSv/Gy · cm2 ± 0.614) across all diagnostic fluoroscopy examination types. Median effective dose values per IR procedure type ranged from 0.0007 to 3.90 mSv (mean, 0.6757 mSv ± 0.8989). Calculated DAP-to-effective dose conversion factors ranged from 0.001 to 0.87 mSv/Gy · cm2 (mean, 0.210 mSv/Gy · cm2 ± 0.235) across all IR procedure types. Conclusion A pediatric fluoroscopy dose catalog was created, including age-specific effective dose, using a repeatable robust method based on accurate clinical data. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Borrego and Balter in this issue.

Imaging of Vesicoureteral Reflux: AJR Expert Panel Narrative Review

Vesicoureteral reflux (VUR) is a common congenital anomaly of the urinary tract that can present with collecting system dilation or as a febrile infection. VUR can lead to permanent renal sequela requiring surgery but can also spontaneously resolve without complication. Therefore, it is important to recognize those patient populations who warrant imaging for screening, confirmation, or ongoing surveillance for VUR, while avoiding overdiagnosis. In the appropriate patient populations, an accurate diagnosis of VUR allows early treatment and prevention of pyelonephritis and scarring. Various imaging modalities are available to diagnose and grade VUR, including voiding cystourethrogram (VCUG), radionucleotide cystography (RNC), and contrast-enhanced voiding urosonography (ceVUS). The objective of this article is to summarize the current understanding of VUR diagnosis and management and to discuss these imaging modalities' strengths and pitfalls. Considerations include indications for VUR imaging, patient preparation, conduct of the examination, issues related to radiologic reporting, and cost-effectiveness. An emphasis is placed on ceVUS, which is the most recently introduced of the three imaging modalities and is receiving growing support among pediatric radiologists.

Accuracy of contrast-enhanced voiding urosonography using Optison™ for diagnosis of vesicoureteral reflux in children

BACKGROUND

There is limited quality of evidence regarding the accuracy of contrast-enhanced voiding urosonography (ceVUS) for diagnosis of vesicoureteral reflux (VUR) compared to fluoroscopic voiding cystourethrography (VCUG), and minimal data on the use of the ultrasound contrast agent Optison™ for this purpose.

OBJECTIVE

To compare the accuracy of ceVUS using Optison™ to VCUG, and to assess inter-rater agreement regarding presence and grading of VUR.

STUDY DESIGN

In this retrospective investigation, all sequential ceVUS with Optison™ and VCUG studies performed in children between 2014 and 2017 were reviewed. Two raters independently graded all ceVUS studies using a 5-point scale. CeVUS sensitivity and specificity were estimated separately for each rater using the VCUG report as the ground truth for presence and degree of VUR. Logistic and ordinary linear regression models assessed rater-report agreement and inter-rater agreement for each kidney, Optison™ dose, and referral diagnosis.

RESULTS

97 children (51 females) with 101 paired studies were included. Sensitivity and specificity of ceVUS for VUR detection were identical for both raters: right kidney 75%/90.9%; left kidney 85.7%/78.9% (Figure). There was no statistically significant difference in disagreement between raters and the VCUG report for the right or left kidney. Inter-rater agreement on ceVUS grading was 90% and 88% for right and left kidneys, respectively. There was a significant negative association between fetal hydronephrosis vs urinary tract infection and disagreement between Rater 2 and the VCUG report for the left kidney. There were no other significant associations with respect to either kidney, Optison™ dose, or referral diagnosis.

DISCUSSION

Our study showed that detection of VUR with ceVUS and Optison™ is comparable to fluoroscopic VCUG. Based on the VCUG reports, the incidence of VUR in our patient population was substantially lower than in the meta-analysis of Chua et al. and in the study of Kim et al. The explanation for the large discrepancy in VUR incidence may reflect differences in the patient populations, and in our reporting of VUR with respect to kidney number rather than to pelviureteral units. Study limitations include its retrospective nature and potential bias in terms of patient selection. Since VUR is an intermittent phenomenon, sequential rather than simultaneous performance of the ceVUS and fluoroscopic studies might have influenced VUR detection.

CONCLUSION

A blinded comparison of ceVUS performed with Optison™ to fluoroscopic VCUG showed moderate-good sensitivity and specificity for diagnosis of VUR.

Normative values for ureteral diameter in children

BACKGROUND

Assessment of the ureter is a fundamental part of the radiologic evaluation of the urinary tract. Abnormal ureteral dilation warrants further investigation to assess the etiology, which includes obstruction and/or reflux. Despite this fundamental need, there are no established normative values in children based on imaging.

OBJECTIVE

To provide normative values for ureteral diameter in pediatric patients with age-related ranges.

MATERIALS AND METHODS

We retrospectively reviewed all magnetic resonance (MR) urography studies and chose only normal ureters for assessment. The images were analyzed on commercially available software to assess maximum internal diameter. Manual measurements were done in cases where the images were below the resolution for automated assessment. Maximum intraluminal ureteral diameters were measured in upper, mid and lower thirds and the average of the three maximum ureteral diameters was used to obtain the average widest internal ureteral diameter. Multivariable linear regression was performed to test the association between the calculated diameter and gender. Differences in sizes between the left and right ureter were assessed using paired Wilcoxon signed rank test.

RESULTS

One hundred twenty-one MR urography studies were selected, which included 160 ureter units. The diameter increases progressively with age, ranging from 3.2 mm during infancy to 5.0 mm in patients older than 16 years of age. After 9 years of age, the average widest internal ureteral diameter is slightly larger in males compared to females (odds ratio [OR]=1.91, 95% confidence interval [CI] [1.63, 2.25], P<0.0001). The right ureter was slightly larger than the left (3.9 mm vs. 3.7 mm, P=0.004) among 39 patients in whom both right and left ureter units were included. The average mid ureteral diameter is widest, followed by the distal third then proximal third.

CONCLUSION

We present the normative values for the average widest internal ureteral diameter based on laterality and different segments. In the pediatric population, 3.8 mm should be considered the average widest internal ureteral diameter.

2021 update on the urinary tract dilation (UTD) classification system: clarifications, review of the literature, and practical suggestions

In 2014, a multidisciplinary consensus on the classification of pre- and postnatal urinary tract dilation (UTD classification) was developed. Its goal was to provide a standardized system for evaluating and reporting urinary tract dilation both in the prenatal and postnatal periods. In this review, we summarize insights learned from the implementation of the UTD classification system since its inception, providing clarifications on common points of confusion. In addition, we review current literature in the clinical validation of the UTD classification system to provide credence for its use in managing fetuses and children with urinary tract dilation.

The radiologist's role in assessing differences of sex development

When infants are identified with a difference of sex development (DSD), a thoughtful approach to imaging is essential to appropriate clinical management. This review provides a comprehensive guide for radiologists who are tasked with performing this critical assignment. We review the embryologic basis of DSDs, with attention to the imaging findings that can indicate specific diagnoses. We also discuss techniques for optimal imaging, including strategies for identifying the gonads by US, tactics for performing genitograms with fluoroscopy and contrast-enhanced US, and the appropriate utilization of MRI. Finally, we review the clinical data and imaging findings that characterize some of the most common DSDs, including congenital adrenal hyperplasia, complete androgen insensitivity syndrome and gonadal dysgenesis.

Improving Automatic Renal Segmentation in Clinically Normal and Abnormal Paediatric DCE-MRI via Contrast Maximisation and Convolutional Networks for Computing Markers of Kidney Function

There is a growing demand for fast, accurate computation of clinical markers to improve renal function and anatomy assessment with a single study. However, conventional techniques have limitations leading to overestimations of kidney function or failure to provide sufficient spatial resolution to target the disease location. In contrast, the computer-aided analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) could generate significant markers, including the glomerular filtration rate (GFR) and time-intensity curves of the cortex and medulla for determining obstruction in the urinary tract. This paper presents a dual-stage fully modular framework for automatic renal compartment segmentation in 4D DCE-MRI volumes. (1) Memory-efficient 3D deep learning is integrated to localise each kidney by harnessing residual convolutional neural networks for improved convergence; segmentation is performed by efficiently learning spatial-temporal information coupled with boundary-preserving fully convolutional dense nets. (2) Renal contextual information is enhanced via non-linear transformation to segment the cortex and medulla. The proposed framework is evaluated on a paediatric dataset containing 60 4D DCE-MRI volumes exhibiting varying conditions affecting kidney function. Our technique outperforms a state-of-the-art approach based on a GrabCut and support vector machine classifier in mean dice similarity (DSC) by 3.8% and demonstrates higher statistical stability with lower standard deviation by 12.4% and 15.7% for cortex and medulla segmentation, respectively.

Contrast-enhanced voiding urosonography, part 1: vesicoureteral reflux evaluation

Contrast-enhanced voiding urosonography (ceVUS) is a well-established, sensitive and safe ultrasound (US) modality for detecting and grading vesicoureteral reflux (VUR) and urethral imaging in children. Nearly three decades of remarkable advances in US technology and US contrast agents have refined ceVUS's diagnostic potential. The recent approval of Lumason/SonoVue in the United States, Europe and China for pediatric intravesical applications marked the beginning of a new era for this type of contrast US imaging. Consequently, the use of ceVUS in children has expanded to multiple places around the globe. In the first part of this review article, we describe the current experience in the use of ceVUS for VUR evaluation, with an emphasis on historical background, examination technique, image interpretation and diagnostic accuracy. In the second part, we will present the role of ceVUS for urethral imaging in children.

Contrast-enhanced voiding urosonography part 2: urethral imaging

Ultrasound (US) has been increasingly used as an important imaging tool to assess the urethra in children. The earliest reports of pediatric urethral sonography involved imaging the urethra in a non-voiding state, during physiological voiding of urine, and after instillation of saline. The introduction of US contrast agents has continued to improve visualization of urethral anatomy. Contrast-enhanced US of the urethra can be performed during the voiding phase of a standard contrast-enhanced voiding urosonography (ceVUS) exam or with retrograde instillation of a contrast agent, depending on the exam indication. Both techniques are well tolerated by children and provide accurate information about urethral pathology and periurethral soft tissues. This article reviews the technical aspects and imaging findings of urethral pathologies in children using contrast-enhanced US, both by the voiding and retrograde instillation techniques.

Modeling dynamic radial contrast enhanced MRI with linear time invariant systems for motion correction in quantitative assessment of kidney function

Early identification of kidney function deterioration is essential to determine which newborn patients with congenital kidney disease should be considered for surgical intervention as opposed to observation. Kidney function can be measured by fitting a tracer kinetic (TK) model onto a series of Dynamic Contrast Enhanced (DCE) MR images and estimating the filtration rate parameter from the model. Unfortunately, breathing and large bulk motion events due to patient movement in the scanner create outliers and misalignments that introduce large errors in the TK model parameter estimates even when using a motion-robust dynamic radial VIBE sequence for DCE-MR imaging. The misalignments between the series of volumes are difficult to correct using standard registration due to 1) the large differences in geometry and contrast between volumes of the dynamic sequence and 2) the requirement of fast dynamic imaging to achieve high temporal resolution and motion deteriorates image quality. These difficulties reduce the accuracy and stability of registration over the dynamic sequence. An alternative registration approach is to generate noise and motion free templates of the original data from the TK model and use them to register each volume to its contrast-matched template. However, the TK models used to characterize DCE-MRI are tissue specific, non-linear and sensitive to the same motion and sampling artifacts that hinder registration in the first place. Hence, these can only be applied to register accurately pre-segmented regions of interest, such as kidneys, and might converge to local minima under the presence of large artifacts. Here we introduce a novel linear time invariant (LTI) model to characterize DCE-MR data for different tissue types within a volume. We approximate the LTI model as a sparse sum of first order LTI functions to introduce robustness to motion and sampling artifacts. Hence, this model is well suited for registration of the entire field of view of DCE-MR data with artifacts and outliers. We incorporate this LTI model into a registration framework and evaluate it on both synthetic data and data from 20 children. For each subject, we reconstructed the sequence of DCE-MR images, detected corrupted volumes acquired during motion, aligned the sequence of volumes and recovered the corrupted volumes using the LTI model. The results show that our approach correctly aligned the volumes, provided the most stable registration in time and improved the tracer kinetic model fit.

Contrast enhanced colostography: New applications in preoperative evaluation of anorectal malformations

INTRODUCTION

Understanding details of anatomic relationships between the colon and surrounding structures is a critical piece of preoperative planning prior to surgical repair of anorectal malformations (ARMs). Traditional imaging techniques involve ionizing radiation, distention of the rectum with supraphysiologic intraluminal pressures, and sometimes require sedation. Recent developments in the field of contrast agents have allowed the emergence of an ultrasound-based technique that can avoid these requirements while continuing to provide high resolution structural information in three dimensions.

METHODS

Fourteen children (13 male, 1 female, age 1-11 months) with ARMs underwent contrast enhanced colostography (ceCS) in addition to traditional preoperative imaging techniques to delineate anatomic relationships of pelvic structures.

RESULTS

ceCS and traditional imaging yielded concordant anatomic information, including structural relationships and fistulous connections, in 10/14 patients (71%). ceCS detected fistulous connection in 2/13 patients (15%) that were not seen by traditional imaging. Ultrasonography failed to detect the fistulous connection in one patient.

CONCLUSIONS

ceCS is a safe, effective and flexible method for defining important structural information in ARM patients. When compared with traditional methods, it provided equivalent or superior results 93% of the time and bears consideration as a standard tool in preoperative planning for this population.

TYPE OF STUDY

Retrospective Comparative Study.

LEVEL OF EVIDENCE

Level III.

Assessment of urinary tract dilation grading amongst pediatric urologists

INTRODUCTION

The Urinary Tract Dilation (UTD) system was created to address variability in hydronephrosis grading. It is unknown if or how pediatric urologists are integrating this newer system into practice.

OBJECTIVE

We sought to evaluate the current use of hydronephrosis grading systems, inter-rater reliability (IRR) for individual systems, and management preferences based on degree of hydronephrosis.

STUDY DESIGN

A survey was emailed to the Societies for Pediatric Urology listserv. Questions addressed familiarity/preference for various grading systems and respondent confidence in interpretation of hydronephrosis. Three clinical vignettes asked respondents to grade hydronephrosis using their system of choice and report further imaging they would obtain. Descriptive statistics were calculated, and IRR was calculated using a linear-weighted modified Fleiss' kappa test.

RESULTS

Response rate was 43% (n = 138). The majority of respondents used Society for Fetal Urology (SFU) (70%) or UTD (19%) systems. Most favored SFU (58%) or UTD (34%) systems for a unified system. Confidence in own interpretation was higher than confidence in radiologists' reads (median 4.4 vs 3.6, p < 0.001). IRR was substantial for UTD (κ0.68 [0.64-0.71]) and moderate for SFU (κ0.60 [0.52-0.76]). There was notable heterogeneity regarding follow-up imaging for cases. There was no difference in requested follow-up studies between SFU and UTD systems, except for fewer voiding cystourethrogram (VCUG) requests for Case 3 with UTD (28% vs 4%, p = 0.02).

CONCLUSION

Most pediatric urologists still use SFU rather than the UTD system. There was slightly higher IRR with the UTD system. There was substantial variability in follow-up imaging not related to grading system, except with low grade hydronephrosis.

Bulk motion-compensated DCE-MRI for functional imaging of kidneys in newborns

BACKGROUND

Evaluation of kidney function in newborns with hydronephrosis is important for clinical decisions. Dynamic contrast-enhanced (DCE) MRI can provide the necessary anatomical and functional information. Golden angle dynamic radial acquisition and compressed sensing reconstruction provides sufficient spatiotemporal resolution to achieve accurate parameter estimation for functional imaging of kidneys. However, bulk motion during imaging (rigid or nonrigid movement of the subject resulting in signal dropout) remains an unresolved challenge.

PURPOSE

To evaluate a motion-compensated (MoCo) DCE-MRI technique for robust evaluation of kidney function in newborns. Our method includes: 1) motion detection, 2) motion-robust image reconstruction, 3) joint realignment of the volumes, and 4) tracer-kinetic (TK) model fitting to evaluate kidney function parameters.

STUDY TYPE

Retrospective.

SUBJECTS

Eleven newborn patients (ages <6 months, 6 female).

FIELD STRENGTH/SEQUENCE

3T; dynamic "stack-of-stars" 3D fast low-angle shot (FLASH) sequence using a multichannel body-matrix coil.

ASSESSMENT

We evaluated the proposed technique in terms of the signal-to-noise ratio (SNR) of the reconstructed images, the presence of discontinuities in the contrast agent concentration time curves due to motion with a total variation (TV) metric and the goodness of fit of the TK model, and the standard variation of its parameters.

STATISTICAL TESTS

We used a paired t-test to compare the MoCo and no-MoCo results.

RESULTS

The proposed MoCo method successfully detected motion and improved the SNR by 3.3 (P = 0.012) and decreased TV by 0.374 (P = 0.017) across all subjects. Moreover, it decreased nRMSE of the TK model fit for the subjects with less than five isolated bulk motion events in 6 minutes (mean 1.53, P = 0.043), but not for the subjects with more frequent events or no motion (P = 0.745 and P = 0.683).

DATA CONCLUSION

Our results indicate that the proposed MoCo technique improves the image quality and accuracy of the TK model fit for subjects who present isolated bulk motion events.

LEVEL OF EVIDENCE

3 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;52:207-216.

Feed and wrap magnetic resonance urography provides anatomic and functional imaging in infants without anesthesia

OBJECTIVE

To describe a technique for performing magnetic resonance urogram (MRU) in infants without sedation or anesthesia.

METHODS

Eighteen infants underwent MRU in the absence of sedating medications using a 'feed and wrap' technique (FW-MRU). Dynamic contrast enhanced images were obtained. Dynamic radial VIBE and compressed sensing image reconstruction were used to correct for motion artifact.

RESULTS

Seventeen of the 18 patients had successful FW-MRU. Feed and wrap' magnetic resonance urogram provided high-quality anatomic and functional renal data.

CONCLUSION

Initial experience with FW-MRU demonstrates it to be a promising anesthesia-free modality for obtaining anatomic and functional imaging of the urinary tract in infants.

Case series: Comparison of contrast-enhanced genitosonography (ceGS) to fluoroscopy and cone-beam computed tomography in patients with urogenital sinus and the cloacal malformation

In this case series, contrast enhanced genitosonography is compared to genitography performed using fluoroscopy and cone-beam computed tomography in patients with urogenital sinus and the cloacal malformation. The method of contrast enhanced genitosonography is described, including contrast preparation, contrast administration, ultrasound imaging approaches, as well as the benefits and potential pitfalls of this technique compared to fluoroscopy and computed tomography.

Contrast-Enhanced Colosonography for the Evaluation of Children With an Imperforate Anus

This case series describes a novel method for showing the preoperative anatomy of children with anorectal malformations using ultrasound contrast, which we have termed "contrast-enhanced colosonography (ceCS)." Six patients with anorectal malformations without a perineal fistula were studied both by fluoroscopic distal colostography and ceCS, and their results were confirmed surgically. Contrast-enhanced CS precisely showed the complex anatomic relationships in all cases. Compared to traditional fluoroscopic studies, ceCS has the benefit of no associated ionizing radiation and thus is safer for children.

The association of postnatal urinary tract dilation risk score with clinical outcomes

BACKGROUND

There are limited data on the predictive value of the consensus urinary tract dilation (UTD) score with respect to subsequent clinical diagnoses. We sought to define the relationship between postnatal UTD risk score and clinical outcomes during childhood.

METHODS

Complete ultrasound image sets from a random selection of infants aged 0-90 days undergoing initial ultrasound at a single institution for prenatal hydronephrosis between 2012 and 2014 were assigned a UTD score by 1 pediatric urologist and 1 pediatric radiologist. Urinary tract dilation risk score was analyzed for association with a composite outcome comprising urinary tract infection, vesicoureteral reflux (VUR), ureteropelvic junction obstruction, non-refluxing megaureter (NRM), ureterocele, bladder outlet obstruction (BOO), and chronic kidney disease. Surgical intervention and resolution of UTD were evaluated separately. Descriptive and survival analyses were performed.

RESULTS

Urinary tract dilation scores for 494 subjects were P0 in 23.5%, P1 in 26.5%, P2 in 23.5%, and P3 in 26.5%. Seventy-four percent were male. Median age at initial imaging was 28 days; median follow-up was 19.8 months. The composite outcome occurred in 138 of 494 patients (27.9%) and varied significantly (p < 0.001) by UTD score: 11.2% for P0, 10.7% for P1, 29.3% for P2, and 58.8% for P3. On survival analysis (Summary Figure), higher UTD grade was significantly associated with the composite outcome (hazard ratio for P3 vs. P0 was 7.4 [95% CI: 3.44-15.92, p < 0.001]). Urinary tract infection and VUR diagnosis varied by UTD score (p = 0.03 and p < 0.001, respectively). Ureteropelvic junction obstruction was diagnosed (based on MAG3 results) in 6.3% of patients, 84% of whom were P3. Non-refluxing megaureter was diagnosed in 7.7%. Ureterocele and BOO were uncommon (1.4%, and 0.6%, respectively). Surgical intervention was also associated with UTD risk, with 46% of P3 undergoing surgery vs. 1% of P0, 1% of P1, and 6% of P2 (p < 0.001). Resolution of UTD occurred in 41% (median 10.1 months) and varied significantly by UTD risk (p < 0.001).

DISCUSSION

Urinary tract dilation risk score is associated with clinical events, although ascertainment bias may influence some of the differences in outcomes, particularly for VUR, because VCUG utilization varied by the UTD group. The lack of any significant difference in outcomes between patients with UTD P0 versus P1 suggests that the P1 category could be eliminated as it does not meaningfully distinguish between outcome risk.

CONCLUSIONS

Higher UTD risk scores are strongly associated with genitourinary diagnoses during the first two years of life.

Pelvic floor laxity: A not so rare but unrecognized form of daytime urinary incontinence in peripubertal and adolescent girls

INTRODUCTION

Stress urinary incontinence (SUI) is common among older multiparous females but rarely reported in active, young girls.

OBJECTIVES

Our hypothesis is: physically active adolescent females develop pelvic floor laxity demonstrable on upright VCUG. Our objectives are to (1) increase awareness of SUI in young females, (2) test our hypothesis with an upright VCUG, and (3) report effectiveness of step-wise management.

STUDY DESIGN

A retrospective review was performed of nulliparous girls with only SUI seen from 2000 to 2015, who were evaluated with upright voiding cystourethrography (VCUG) (bladder descent defined as ≥2 cm drop of bladder neck below pubic ramus at capacity). Data collection included level of physical activity, physical examination, BMI and Z-scores, urodynamics, management, and treatment response. Standard urotherapy (SUT) (timed voiding, proper diet, adequate fluids, bowel management) and biofeedback therapy (BFT) was initiated. Fisher exact test was used to calculate 'p' values.

RESULTS

Thirty-three females (median age 15.1 years, range 5.5-20.3) were identified who underwent an upright VCUG; 20 had bladder neck descent (Fig.). Of these 20, 15 (75%) were involved in strenuous activity, whereas only three of 13 (23%) without descent engaged in intense athletics. No differences were noted in median BMI and Z-score with strenuous activity (21.1 (15.2-26.7) and 0.31 (-0.9-1.94)), respectively, versus patients without (21.3 (15.8-33.5) and 0.62 (-0.0-2.38)). Average follow-up for all was 16.6 months (range 0.4-102.2). Of 20 demonstrating bladder neck descent, three did not complete therapy and were lost to follow-up. Only six of these 17 became dry. Of the remaining 11, eight underwent surgery: Burch colposuspension (5), fascial sling (2), Coaptite to the bladder neck (1), and an artificial urinary sphincter (1). This latter girl had a failed Burch colposuspension 1 year previously. All surgical patients are dry. Of 13 without bladder descent on VCUG, five did not complete therapy and were lost to follow-up. The remaining eight were managed non-surgically; seven were fully dry at last follow-up. Overall, 13 of 25 (52%) achieved dryness. SUT and BFT were more effective in those without, than in those with bladder descent (87.5% vs. 35.3%, p = 0.0302, Fisher exact test).

DISCUSSION AND CONCLUSIONS

Physically active, nulligravid girls with SUI can be efficaciously diagnosed on upright VCUG. They should be considered for non-surgical therapy but will likely require bladder neck elevating surgery. Non-surgical therapy works for those with minimal bladder descent on cystography.

Common genitourinary catheters: a systematic approach for the radiologist

Catheters are commonly used to treat and diagnose urinary tract abnormalities in the pediatric population. This pictorial essay reviews commonly placed genitourinary catheters imaged by radiography, fluoroscopy, computed tomography (CT) and ultrasonography (US). The purpose of the catheter, how the catheter is placed, and the imaging findings associated with appropriately positioned catheters as well as misplaced and displaced catheters are described. It is important for radiologists to recognize common genitourinary catheters, and be familiar with their normal and abnormal positions as displacement is often first recognized by diagnostic imaging.

Case of urethral duplication seen by voiding urosonography

A 3-month-old premature male infant with imperforate anus and hypospadias underwent contrast-enhanced voiding urosonography (ceVUS) followed by voiding cystourethrography (VCUG). Images from the ceVUS demonstrated a distinct linearity arising dorsally from the posterior urethra that partially opacified with contrast. VCUG confirmed a urethral duplication. To our knowledge, this exceedingly rare anomaly has yet to be reported by ceVUS.

The duplicated collecting system of the urinary tract: embryology, imaging appearances and clinical considerations

Duplication anomalies of the urinary collecting system are common and can be discovered and characterized with multiple imaging modalities. The embryology, imaging manifestations and clinical ramifications of duplicated ureters and renal collecting systems vary from a normal anatomical variant to urological pathology and are discussed and illustrated in this review.

Variation in the level of detail in pediatric voiding cystourethrogram reports

INTRODUCTION

Voiding cystourethrogram (VCUG) provides a wealth of data on urinary tract function and anatomy, but few standards exist for reporting VCUG findings.

OBJECTIVE

We aimed to assess variability in VCUG reports and to test our hypothesis that VCUG reports from pediatric facilities and pediatric radiologists are more complete than those performed at other facilities or by non-pediatric radiologists.

STUDY DESIGN

We analyzed original VCUG reports from children enrolled in the Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) trial. A 23-item checklist was created and used to evaluate reporting of technical (e.g. catheter size), anatomic (e.g. vesicoureteral reflux (VUR) presence and grade, bladder shape), and functional information (e.g. bladder emptying). Radiologists were classified as pediatric or non-pediatric radiologists. Facilities were categorized as to whether they were a free-standing pediatric hospital (FSPH), a pediatric "hospital within a hospital" (PHWH), a non-pediatric hospital (NPH), or an outpatient radiology facility (ORF). Multivariate linear regression was used to analyze factors associated with the completeness of the VCUG reports (percent of items reported from the 23-item checklist).

RESULTS

Six-hundred and two VCUGs were performed at 90 institutions. Of those, 76% were read by a pediatric radiologist, and 49% were performed at a FSPH (Table). On average, less than half of the 23 items in our standardized assessment tool were included in VCUG reports (mean 48%, SD 12). The completeness of reports varied by facility type: 51% complete at FSPH (SD 11), 50% at PHWH (SD 10), 36% at NPH (SD 11), and 43% at ORF (SD 8) (p < 0.0001). In multivariate analysis, VCUG reports generated at NPH or ORF had 8% fewer items included (95% CI 3.0-12.8, p < 0.01), and those generated at PHWH did not differ from those generated at FSPH. Reports read by a non-pediatric radiologist had 6% fewer items included (95% CI 3-9.7; p < 0.01) compared with those read by a pediatric radiologist.

DISCUSSION

There is substantial underreporting of findings in VCUG reports when assessing a widely represented sample of routine, community-generated reports using an idealized standard. Although VUR was often reported, other crucial anatomic and functional findings of the VCUG were consistently underreported across all facility types.

CONCLUSION

Although pediatric radiologist and pediatric hospitals generated more complete VCUG reports compared with those having non-pediatric origins, the differences are small when considering the substantial underreporting of VCUG findings in general. This underscores the opportunities for improvement in reporting of VCUG findings.

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.

MRI-based reference range for the renal pelvis anterior-posterior diameter in children ages 0-19 years

OBJECTIVE

To determine the mean and normal range of anteroposterior diameter (APD) of the renal pelves in children.

METHODS

Patients aged 0-19 years with normal spinal MRIs were identified after institutional review board approval. Those with dilating uropathy or abdominal surgery/radiation were excluded. The maximum APD was measured. A mixed linear model was fit to determine the relationship between APD and age, adjusted for bladder distention. The left and right kidneys were treated independently.

RESULTS

283 left and 285 right renal units were included. For the left, a 3.5% increase in APD per year was predicted (p < 0.0001), with the average APD for infants and 18-year olds with non-distended bladders being 2.5 mm (95th percentile: 7.2 mm) and 4.6 mm (13.4 mm), respectively. For the right, a 3.9% increase in APD per year was predicted (p < 0.0001), with the average APD for infants and 18-year olds with non-distended bladders being 2.8 mm (8.4 mm) and 5.5 mm (16.6 mm), respectively. Compared with a non-distended bladder, a distended bladder increased the predicted APD between 23% (right) and 38% (left) (p = 0.01 and p < 0.0001, respectively).

CONCLUSION

The mean and normal ranges of APD measured by MRI in children are provided. APD increases with age and bladder distension and is greater on the left. Advances in knowledge: This article establishes normative ranges for APD, a critical component of genitourinary tract evaluation, and does so using the most precise imaging modality for this condition.

Intrarenal Reflux: Diagnosis at Contrast-Enhanced Voiding Urosonography

Vesicoureteral reflux (VUR) is a childhood condition that is usually diagnosed by fluoroscopic voiding cystourethrography (VCUG). Intrarenal reflux (IRR) of infected urine is believed to play an important role in the pathogenesis of reflux-associated pyelonephritis and subsequent parenchymal scarring and is traditionally depicted by fluoroscopic VCUG. This case series describes the phenomenon of IRR occurring in association with VUR in 4 children as depicted by contrast-enhanced voiding urosonography. The ability of contrast-enhanced voiding urosonography to show IRR when it occurs in conjunction with VUR compares favorably to that of fluoroscopic VCUG.

Sperm Retrieval in Adolescents and Young Adults with Klinefelter Syndrome: A Prospective, Pilot Study

OBJECTIVE

To assess sperm retrieval rates in adolescents and young adults with Klinefelter syndrome, with the ultimate goal of improving fertility in this population. Secondary aims were to evaluate other clinical characteristics of the cohort and identify predictors of sperm retrieval.

STUDY DESIGN

Patients 12-25 years of age with Klinefelter syndrome (47,XXY) were recruited at the Boston Children's Hospital. Physical examination, biochemical evaluation, scrotal ultrasonography, and semen analysis were performed. Neurocognitive data were collected. Microdissection sperm extraction (unilateral micro-testicular sperm extraction) was offered to individuals with no sperm in their ejaculates. Given the small sample size, analysis was primarily descriptive.

RESULTS

Fifteen patients were enrolled. None had sperm in their ejaculates. Ten patients underwent unilateral micro-testicular sperm extraction. Sperm retrieval rate was 50%. From a neurocognitive standpoint, subjects reported problems with peers, conduct, and overall difficulties. Incidentally, one-third of the patients were found to have testicular microlithiasis and 17% of subjects with renal ultrasound imaging had bilateral renal medullary nephrocalcinosis.

CONCLUSIONS

This pilot study suggests that sperm retrieval rates in adolescents and young adults with Klinefelter syndrome are comparable with those reported in older men. However, larger studies are needed to confirm our findings. The clinical significance of the scrotal and renal ultrasound findings merits further investigation.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01817296.

The role of imaging in pediatric bladder augmentation

Bladder augmentation (also called augmentation cystoplasty) refers to a number of surgical methods that increase the capacity and compliance of the urinary bladder. Imaging has an important role in the postoperative evaluation of bladder augmentation. The most common augmentation procedures utilize enteric segments to augment the bladder. The various types of bladder augmentation have characteristic appearances on different imaging modalities. Spontaneous bladder perforation is a complication that is seen in both early and late post-operative periods and it is one of the most important complications for radiologists to be aware of as it is life-threatening. We review the indications for bladder augmentation in children, the surgical techniques employed, the normal postoperative appearances on imaging studies and the role of imaging complications of bladder augmentation including delayed spontaneous bladder rupture, which is life-threatening.

Predictive value of specific ultrasound findings when used as a screening test for abnormalities on VCUG

BACKGROUND

Renal and bladder ultrasound (RBUS) is often used as an initial screening test for children after urinary tract infection (UTI), and the 2011 AAP guidelines specifically recommend RBUS be performed first, with voiding cystourethrogram (VCUG) to be performed only if the ultrasound is abnormal. It is uncertain whether specific RBUS findings, alone or in combination, might make RBUS more useful as a predictor of VCUG abnormalities.

AIMS

To evaluate the association of specific RBUS with VCUG findings, and determine whether predictive models that accurately predict patients at high risk of VCUG abnormalities, based on RBUS findings, can be constructed.

METHODS

and study sample: A total of 3995 patients were identified with VCUG and RBUS performed on the same day. The RBUS and VCUG reports were reviewed and the findings were classified. Analysis was limited to patients aged 0-60 months with no prior postnatal genitourinary imaging and no history of prenatal hydronephrosis.

ANALYSIS

The associations between large numbers of specific RBUS findings with abnormalities seen on VCUG were investigated. Both multivariate logistic models and a neural network machine learning algorithms were constructed to evaluate the predictive power of RBUS for VCUG abnormalities (including VUR or bladder/urethral findings). Sensitivity, specificity, predictive values and area under receiving operating curves (AUROC) of RBUS for VCUG abnormalities were determined.

RESULTS

A total of 2259 patients with UTI as the indication for imaging were identified. The RBUS was reported as "normal" in 75.0%. On VCUG, any VUR was identified in 41.7%, VUR grade > II in 20.9%, and VUR grade > III in 2.8%. Many individual RBUS findings were significantly associated with VUR on VCUG. Despite these strong univariate associations, multivariate modeling didn't result in a predictive model that was highly accurate. Multivariate logistic regression built via stepwise selection had: AUROC = 0.57, sensitivity = 86% and specificity = 25% for any VUR; AUROC = 0.60, sensitivity = 5% and specificity = 99% for VUR grade > II; and AUROC = 0.67, sensitivity = 6% and specificity = 99% for VUR grade > III. The best predictive model constructed via neural networks had: AUROC = 0.69, sensitivity = 64% and specificity = 60% for any VUR; AUROC = 0.67, sensitivity = 18% and specificity = 98% for VUR grade > II; and AUROC = 0.79, sensitivity = 32% and specificity = 100% for VUR grade > III.

CONCLUSIONS

Even with the state-of-the-art predictive models, abnormal findings on RBUS provide a poor screening test for genitourinary abnormalities. Renal bladder ultrasound and VCUG should be considered complementary, as they provide important, but different, information.

Variation in the documentation of findings in pediatric voiding cystourethrogram

BACKGROUND

Few standards exist for reporting results of voiding cystourethrogram (VCUG).

OBJECTIVE

To assess the variation in reporting of VCUG findings from different facilities using a standardized assessment tool.

MATERIALS AND METHODS

VCUG reports were evaluated for demographic, technical, anatomical and functional information. Reports were categorized by age, gender, indication and vesicouretal reflux (VUR) status. Institutions were classified as a free-standing pediatric hospital (n = 3), pediatric hospital within a hospital (n = 11), or non-pediatric facility (n = 24) and reports were classified as having been read by a pediatric radiologist or not. Each category of outside reports (n = 152) was randomly matched with a twice-larger group of Hospital A reports from the same category (n = 304). Multivariate linear regression was used to analyze the association between the primary outcome (percentage of items described in dictated VCUG report) and the type of radiologist and institution.

RESULTS

Of the 456 studies, 66% were in girls, 56% were in those <12 months old, and the indication was urinary tract infection (UTI) in 81%. The mean percentage of items reported was 67 ± 14% (74 ± 7% at free-standing pediatric hospitals, 61 ± 10% at pediatric hospitals within a hospital, and 48 ± 11% at non-pediatric facilities). In multivariate analysis, VCUG reports generated at non-pediatric facilities had 17% fewer items included (95% CI: 14.5-19.7%, P < 0.0001), and pediatric hospitals within a hospital had 9% fewer items included (5.9-12.5%, P < 0.0001) when compared to free-standing pediatric hospitals. Reports read by a pediatric radiologist had 12% more items included (9.1-15.3%, P < 0.0001) compared to those read by a non-pediatric radiologist.

CONCLUSION

More complete VCUG reports were observed when generated at free-standing pediatric hospitals and when interpreted by a pediatric radiologist.

Bladder exstrophy: current management and postoperative imaging

Bladder exstrophy is a rare malformation characterized by an infra-umbilical abdominal wall defect, incomplete closure of the bladder with mucosa continuous with the abdominal wall, epispadias, and alterations in the pelvic bones and muscles. It is part of the exstrophy-epispadias complex, with cloacal exstrophy on the severe and epispadias on the mild ends of the spectrum. Bladder exstrophy is the most common of these entities and is more common in boys. The goal of this paper is to describe common methods of repair and to provide an imaging review of the postoperative appearances.

Ultrasound as a screening test for genitourinary anomalies in children with UTI

BACKGROUND

The 2011 American Academy of Pediatrics guidelines state that renal and bladder ultrasound (RBUS) should be performed after initial febrile urinary tract infection (UTI) in a young child, with voiding cystourethrogram (VCUG) performed only if RBUS shows abnormalities. We sought to determine test characteristics and predictive values of RBUS for VCUG findings in this setting.

METHODS

We analyzed 3995 clinical encounters from January 1, 2006 to December 31, 2010 during which VCUG and RBUS were performed for history of UTI. Patients who had previous postnatal genitourinary imaging or history of prenatal hydronephrosis were excluded. Sensitivity, specificity, and predictive values of RBUS for VCUG abnormalities were determined.

RESULTS

We identified 2259 patients age <60 months who had UTI as the indication for imaging. RBUS was reported as "normal" in 75%. On VCUG, any vesicoureteral reflux (VUR) was identified in 41.7%, VUR grade >II in 20.9%, and VUR grade >III in 2.8%. Sensitivity of RBUS for any abnormal findings on VCUG ranged from 5% (specificity: 97%) to 28% (specificity: 77%). Sensitivity for VUR grade >III ranged from 18% (specificity: 97%) to 55% (specificity: 77%). Among the 1203 children aged 2 to 24 months imaged after a first febrile UTI, positive predictive value of RBUS was 37% to 47% for VUR grade >II (13% to 24% for VUR grade >III); negative predictive value was 72% to 74% for VUR grade >II (95% to 96% for VUR grade >III).

CONCLUSIONS

RBUS is a poor screening test for genitourinary abnormalities. RBUS and VCUG should be considered complementary as they provide important, but different, information.

Nationwide emergency department imaging practices for pediatric urolithiasis: room for improvement

PURPOSE

Children are particularly vulnerable to the harmful effects of medical radiation, and children with urolithiasis comprise a group that may undergo repeated radiation intensive imaging tests. We sought to characterize imaging practices for children presenting to the emergency department with suspected urolithiasis and to determine factors associated with the choice of imaging study.

MATERIALS AND METHODS

Using the 2006 to 2010 Nationwide Emergency Department Sample, we conducted a retrospective cohort study of patients younger than 18 years presenting with suspected urolithiasis. We determined imaging practices for visits to emergency departments where billing codes for computerized tomography and ultrasound were reliably reported. Logistic regression was used to delineate patient and hospital level factors associated with the use of computerized tomography vs ultrasound.

RESULTS

We identified 18,096 pediatric visits for suspected urolithiasis in the 1,191 Nationwide Emergency Department Sample emergency departments with reliable imaging codes. A total of 11,215 patients underwent computerized tomography alone, ultrasound alone or both. Of the patients 9,773 (87%) underwent computerized tomography alone. Computerized tomography use peaked in 2007 and declined thereafter. On multivariate analysis several factors were associated with the use of computerized tomography alone, including smaller proportion of pediatric patients treated at the emergency department, older age, location in the Midwest or South, evaluation at a nonteaching hospital and visit on a weekend.

CONCLUSIONS

Computerized tomography use is highly prevalent for children presenting with suspected urolithiasis. The lowest computerized tomography use is in emergency departments that care for more children. Ultrasound is used infrequently regardless of site. Awareness regarding risks of computerized tomography and consideration of alternatives including ultrasound are warranted in caring for these patients.

Prospective systematic intervention to reduce patient exposure to radiation during pediatric ureteroscopy

PURPOSE

After prospective measurement of radiation exposure during pediatric ureteroscopy for urolithiasis, we identified targets for intervention. We sought to systematically reduce radiation exposure during pediatric ureteroscopy.

MATERIALS AND METHODS

We designed and implemented a pre-fluoroscopy quality checklist for patients undergoing ureteroscopy at our institution as part of a quality improvement initiative. Preoperative patient characteristics, operative factors, fluoroscopy settings and radiation exposure were recorded. Primary outcomes were the entrance skin dose in mGy and midline dose in mGy before and after checklist implementation.

RESULTS

We directly observed 32 consecutive ureteroscopy procedures using the safety checklist, of which 27 were done in pediatric patients who met study inclusion criteria. Outcomes were compared to those in 37 patients from the pre-checklist phase. Pre-checklist and postchecklist groups were similar in patient age, total operative time or patient thickness. The mean entrance skin dose and midline dose were decreased by 88% and 87%, respectively (p <0.01). Significant improvements were noted among the major radiation dose determinants, total fluoroscopy time (reduced by 67%), dose rate setting (appropriately reduced dose setting in 93% vs 51%) and excess skin-to-intensifier distance (reduced by 78%, each p <0.01).

CONCLUSIONS

After systematic evaluation of our practices and implementation of a fluoroscopy quality checklist, there were dramatic decreases in radiation doses to children during ureteroscopy.

Postnatal longitudinal evaluation of children diagnosed with prenatal hydronephrosis: insights in natural history and referral pattern

OBJECTIVES

Clinical significance and management of prenatal hydronephrosis (PNH) are sources of debate. Existing studies are flawed with biased cohorts or inconsistent follow-up. We aimed to evaluate the incidence of pathology in a large cohort of PNH and assess the biases and outcomes of this population.

METHODS

We reviewed 1034 charts of fetuses with PNH. Records of delivered offspring were reviewed at a pediatric center and analyzed with respect to prenatal and postnatal pathology and management.

RESULTS

Prenatal resolution of hydronephrosis occurred in 24.7% of pregnancies. On first postnatal ultrasound, some degree of dilatation was present in 80%, 88% and 95% of mild, moderate and severe PNH cases, respectively. At the end of follow-up, hydronephrosis persisted in 10%, 25% and 72% of children, respectively. Incidence of vesicoureteral reflux did not correlate with severity of PNH. Children with postnatal workup had more severe PNH than those without.

CONCLUSIONS

Despite prenatal resolution totalizing 25%, pelvic dilatation persisted on first postnatal imaging in most cases, thus justifying postnatal ultrasound evaluation. Whereas most mild cases resolved spontaneously, a quarter of moderate and more than half of severe cases required surgery. Patients with postnatal imaging and referral had more severe PNH, which could result in overestimation of pathology.

A novel method of evaluating ureteropelvic junction obstruction: dynamic near infrared fluorescence imaging compared to standard modalities to assess urinary obstruction in a swine model

PURPOSE

Dynamic near infrared fluorescence imaging of the urinary tract provides a promising way to diagnose ureteropelvic junction obstruction. Initial studies demonstrated the ability to visualize urine flow and peristalsis in great detail. We analyzed the efficacy of near infrared imaging in evaluating ureteropelvic junction obstruction, renal involvement and the anatomical detail provided compared to conventional imaging modalities.

MATERIALS AND METHODS

Ten swine underwent partial or complete unilateral ureteral obstruction. Groups were survived for the short or the long term. Imaging was performed with mercaptoacetyltriglycine diuretic renogram, magnetic resonance urogram, excretory urogram, ultrasound and near infrared imaging. Scoring systems for ureteropelvic junction obstruction were developed for magnetic resonance urogram and near infrared imaging. Physicians and medical students graded ureteropelvic junction obstruction based on magnetic resonance urogram and near infrared imaging results.

RESULTS

Markers of vascular and urinary dynamics were quantitatively consistent among control renal units. The same markers were abnormal in obstructed renal units with significantly different times of renal phase peak, start of pelvic phase and start of renal uptake. Such parameters were consistent with those obtained with mercaptoacetyltriglycine diuretic renography. Near infrared imaging provided live imaging of urinary flow, which was helpful in identifying the area of obstruction for surgical planning. Physicians and medical students categorized the degree of obstruction appropriately for fluorescence imaging and magnetic resonance urogram.

CONCLUSIONS

Near infrared imaging offers a feasible way to obtain live, dynamic images of urine flow and ureteral peristalsis. Qualitative and quantitative parameters were comparable to those of conventional imaging. Findings support fluorescence imaging as an accurate, easy to use method of diagnosing ureteropelvic junction obstruction.

Patient and family impact of pediatric genitourinary diagnostic imaging tests

PURPOSE

The impact of diagnostic genitourinary imaging on patients and families is poorly understood. We measured patient and family reaction to commonly performed genitourinary imaging studies using a standardized measurement tool.

MATERIALS AND METHODS

We surveyed families undergoing genitourinary imaging (renal ultrasound, voiding cystourethrography, radionuclide cystogram, static renal scintigraphy and diuretic renal scintigraphy) using a Likert scaled 11-item survey to assess impact across 4 domains (pain, anxiety, time, satisfaction). Survey scores were analyzed using ANOVA and linear regression.

RESULTS

A total of 263 families were surveyed (61 renal ultrasound, 52 voiding cystourethrogram, 55 radionuclide cystogram, 47 mercaptoacetyltriglycine dynamic renal scintigraphy, 48 dimercaptosuccinic acid static renal scintigraphy). Mean patient age was 2.1 years old. Of the patients 45% were male and 77% were white. Patient age, gender and prior genitourinary imaging experience varied by study type. Study type was significantly associated with total and weighted scores on the genitourinary imaging survey (both p <0.0001). Renal ultrasound was scored as better and mercaptoacetyltriglycine dynamic renal scintigraphy was worse than voiding cystourethrogram, radionuclide cystogram and dimercaptosuccinic acid static renal scintigraphy, which did not differ from each other. Other factors associated with worse total scores included patient age 1 to 3 years (p <0.001) and nonwhite race (p = 0.04). Gender, prior testing history, wait time and parent education were not associated with total scores. In the multivariate model renal ultrasound remained the best and mercaptoacetyltriglycine dynamic renal scintigraphy the worst (p <0.0001). In a direct comparison dimercaptosuccinic acid static renal scintigraphy and voiding cystourethrogram total scores did not differ (p = 0.59).

CONCLUSIONS

There were significant differences among genitourinary imaging studies regarding the patient/family experience, but there was no overall difference between dimercaptosuccinic acid static renal scintigraphy and voiding cystourethrogram. These findings may be useful to aid decision making when considering genitourinary imaging for children.

Prospective measurement of patient exposure to radiation during pediatric ureteroscopy

PURPOSE

Few data have been reported regarding radiation exposure during pediatric endourological procedures, including ureteroscopy. We measured radiation exposure during pediatric ureteroscopy and identify opportunities for exposure reduction.

MATERIALS AND METHODS

We prospectively observed ureteroscopy procedures as part of a quality improvement initiative. Preoperative patient characteristics, operative factors, fluoroscopy settings and radiation exposure were recorded. Our outcomes were entrance skin dose and midline dose (both mGy). Specific modifiable factors were identified as targets for potential quality improvement.

RESULTS

Direct observation was performed in 54 consecutive ureteroscopy procedures. Mean±SD patient age was 14.8±3.8 years (range 7.4 to 19.2), with 9 children being younger than 12 years. Mean±SD entrance skin dose was 46.4±48 mGy. Mean±SD midline dose was 6.2±5.0 mGy. The most important major determinant of radiation dose was total fluoroscopy time (mean±SD 2.68±1.8 minutes) followed by dose rate setting, child anteroposterior diameter and source to skin distance (all p<0.01). Analysis of factors affecting exposure levels revealed that use of ureteral access sheaths (p=0.01) and retrograde pyelography (p=0.04) were significantly associated with fluoroscopy time. We also found that dose rate settings were higher than recommended in up to 43% of cases and ideal C-arm positioning could have reduced exposure by 14% (up to 49% in some cases).

CONCLUSIONS

Children receive biologically significant radiation doses during ureteroscopy procedures. Several modifiable factors contribute to dose and could be targeted in efforts to implement dose reduction strategies.

Sonourethrogram to manage adolescent anterior urethral stricture

PURPOSE

Accurate measurement of anterior urethral stricture length is critical to determine the appropriate surgical approach. Retrograde urethrogram is often used to determine stricture location and length. However, the adult literature shows that retrograde urethrogram may underestimate stricture length. We investigated the role of sonographic urethrogram in the preoperative evaluation of adolescent urethral stricture disease.

MATERIALS AND METHODS

Between June 2008 and February 2009 we retrospectively evaluated 12 pediatric patients with urethral stricture disease using retrograde and sonographic urethrogram. Stricture length was categorized by 2 radiologists as I-less than 1, II-1 to 3 and III-greater than 3 cm. On sonographic urethrogram stricture length was measured as the longest extent of the urethral abnormality.

RESULTS

Mean patient age was 16.9 years (range 9.5 to 20.8). Retrograde urethrogram classified 7 cases as category I, 4 as category II and none as category III stricture, and 1 with no evidence of stricture. Sonographic urethrogram revealed strictures greater than 1 cm in all 7 category I cases and 2 of the 4 category II cases had strictures longer than 3 cm. One patient in whom retrograde urethrogram showed a category II stricture was stricture-free on sonographic urethrogram. One patient with a negative retrograde urethrogram had a stricture on sonographic urethrogram. Sonographic urethrogram upgraded stricture length in 10 of the 12 patients and outperformed retrograde urethrogram in 11.

CONCLUSIONS

Sonographic urethrogram is effective for evaluating adolescent urethral stricture disease. It may provide more accurate measurement of stricture length and improve preoperative planning.

Sonographic findings of ovarian torsion in children

BACKGROUND

The clinical diagnosis of ovarian torsion is challenging and findings on pelvic sonography can be pivotal in making the correct diagnosis.

OBJECTIVE

To determine the sonographic characteristics in children of surgically and pathologically proven ovarian torsion.

MATERIAL AND METHODS

We performed a retrospective review of the sonograms and medical records of 41 patients with surgically and pathologically proven ovarian torsion at a pediatric hospital between 1994 and 2005. All sonograms were reviewed retrospectively by two pediatric radiologists with attention to the size, echotexture, location, presence of peripheral round cysts, and evidence of flow on Doppler sonography within the torsed ovary. The amount of free pelvic fluid was also recorded.

RESULTS

The most common sonographic finding of ovarian torsion was an enlarged ovary/adnexal mass. All torsed adnexa were larger than the normal contralateral ovary, with the median volume 12 times that of the normal contralateral side. The majority (61%, n = 25) of the torsions occurred on the right. Color flow, either venous or arterial, was present in 62% (n = 21/34) of the torsed ovaries for which flow on Doppler sonography was documented. In 63% of the torsed ovaries (n = 26), the torsed adnexa appeared heterogeneous. Ovarian or para-ovarian pathology that may have acted as a potential lead point was present in 55% (n = 24) of torsed ovaries. The volume ratio of the torsed to normal ovary can predict the presence of an ovarian mass within the torsed ovary. In 70% of torsed ovaries with a volume ratio greater than 20, an ovarian mass was present, and in approximately 90% of those with a volume ratio less than 20, an internal mass was absent.

CONCLUSION

An enlarged heterogeneous appearing ovary is the most common finding in ovarian torsion. The presence or absence of flow by Doppler sonography is not helpful in the diagnosis. The volume ratio of the torsed to the normal ovary can predict the presence of an internal mass within the torsed adnexa.