Retrograde urethrography in children: a decade of experience at a children's hospital.

BACKGROUND: Retrograde urethrography (RUG) is a radiologic procedure that optimizes imaging evaluation of the urethra, particularly in settings of difficulty with micturition or urethral injury. OBJECTIVE: To review our experience with RUG at a large pediatric radiology practice. MATERIALS AND METHODS: We conducted a retrospective review of medical records and fluoroscopic images of RUGs performed from January 2010 to December 2020. RESULTS: We identified 180 RUG exams (median frequency 17 exams per year), all in male children (median age 13 years). The most common indications were stricture (42%; n=76), postsurgical evaluation (34%; n=62) and trauma (16%; n=29). The most commonly used catheter was Foley (40%; n=72), with a median catheter size of 5 French (Fr) for infants younger than 1 year, 7 Fr for children ages 1-5 years and 8 Fr for children older than 5 years. About a third of the children (57; 32%) had combined voiding cystourethrography (VCUG)-RUG exams. Water-soluble contrast agent, either 17% or 43% Cysto-Conray, was used. Most RUG exams were normal (46%; n=83). The most common urethral pathology was stricture (30%; n=54), commonly involving a bulbar urethra (n=26). Urethral trauma was seen in 11 children (6%), 10 bulbar and 1 membranous. Most children with stricture were surgically treated (n=40; 74%), whereas most children with trauma were conservatively treated (n=8; 73%). The remaining diagnoses included diverticula, polyps, valves, fistulas and duplications, constituting <17% of our sample; most of these were surgically treated. Four exams (2%) were non-diagnostic. RUG showed 89% sensitivity and 97% specificity compared to cystourethroscopy/VCUG findings. Technical difficulties occurred in 14 (8%) children (e.g., pain or inappropriate catheter seal). CONCLUSION: Our experience indicates that when catheterization techniques are properly tailored, RUG provides a useful and successful radiologic method of evaluating the pediatric male urethra.

Ultrasound imaging of preterm brain injury: fundamentals and updates.

Neurosonography has become an essential tool for diagnosis and serial monitoring of preterm brain injury. Preterm infants are at significantly higher risk of hypoxic-ischemic injury, intraventricular hemorrhage, periventricular leukomalacia and post-hemorrhagic hydrocephalus. Neonatologists have become increasingly dependent on neurosonography to initiate medical and surgical interventions because it can be used at the bedside. While brain MRI is regarded as the gold standard for detecting preterm brain injury, neurosonography offers distinct advantages such as its cost-effectiveness, diagnostic utility and convenience. Neurosonographic signatures associated with poor long-term outcomes shape decisions regarding supportive care, medical or behavioral interventions, and family members' expectations. Within the last decade substantial progress has been made in neurosonography techniques, prompting an updated review of the topic. In addition to the up-to-date summary of neurosonography, this review discusses the potential roles of emerging neurosonography techniques that offer new functional insights into the brain, such as superb microvessel imaging, elastography, three-dimensional ventricular volume assessment, and contrast-enhanced US.

Validation of Sonographic Fronto-Occipital Ratio Based on Anatomical Landmarks Compared to MR/CT-Derived Indexes in Children with Chiari II and Ventriculomegaly.

INTRODUCTION: Ultrasound (US)-based indexes such as fronto-occipital ratio (FOR) can be used to obtain an acceptable estimation of ventricular volume. Patients with colpocephaly present a unique challenge due to the shape of their ventricles. In the present study, we aimed to evaluate the validity and reproducibility of the modified US-FOR index in children with Chiari II-related ventriculomegaly. METHODS: In this retrospective study, we evaluated Chiari II patients younger than 1 year who underwent head US and MR or CT scans for ventriculomegaly evaluation. MR/CT-based FOR was measured in the axial plane by identifying the widest diameter of frontal horns, occipital horns, and the interparietal diameter (IPD). US-based FOR (US-FOR) was measured using the largest diameter based on the following landmarks: frontal horn and IPD in the coronal plane at the level of the foramen of Monro, IPD just superior to the Sylvian fissures, and occipital horn posterior to the thalami and inferior to the superior margins of the thalami. Intraclass correlation coefficients (ICCs) were used to evaluate inter-rater reliability, and Pearson correlation coefficients and Bland-Altman plots were applied to assess agreement between US and other two modalities. RESULTS: Sixty-three paired US and MR/CT exams were assessed for agreement between US-FOR and MR/CT-FOR measurements. ICC showed an excellent inter-rater reliability for US-FOR (ICC = 0.99, p < 0.001) and MR/CT-FOR (ICC = 0.99, p < 0.001) measurements. The mean (range) values based on US-FOR showed a slight overestimation in comparison with MR/CT-FOR (0.51 [0.36-0.68] vs. 0.46 [0.34-0.64]). The Pearson correlation coefficient showed high cross-modality agreement for the FOR index (r = 0.83, p < 0.001). The Bland-Altman plot showed excellent concordance between US-FOR and MR/CT-FOR with a bias of 0.05 (95% CI: -0.03 to 0.13). CONCLUSION: US-FOR in the coronal plane is a comparable tool for evaluating ventriculomegaly in Chiari II patients when compared with MR/CT-FOR, even in the context of colpocephaly.

Contrast-enhanced genitosonography and colosonography: emerging alternatives to fluoroscopy.

Imaging plays a crucial role in evaluating newborns and infants with cloacal and urogenital malformations. Contrast-enhanced genitosonography (ceGS) and contrast-enhanced colosonography (ceCS) are sensitive and radiation-free alternatives to fluoroscopic genitography and colography for diagnosis and surgical planning. These imaging techniques are performed by instilling a US contrast agent into specific body cavities to define the genitourinary and colorectal anatomy. This review article presents the experience with ceGS and ceCS applications in children, focusing on the background, examination technique, and interpretation of imaging findings, as well as strengths and weaknesses compared to conventional techniques.

Contrast-enhanced ultrasound of the kidneys and adrenals in children.

Pediatric applications of contrast-enhanced ultrasound (CEUS) are growing. Evaluation of the kidneys and adrenal glands in children using intravenous administration of US contrast agents, however, is still an off-label indication. Pediatric CEUS applications for kidneys are similar to those in adults, including ischemic disorders, pseudo- versus real tumors, indeterminate lesions, complex cystic lesions, complicated pyelonephritis, and abscesses. CEUS applications for evaluation of adrenal glands in children are limited, mainly focusing on the assessment and follow-up of adrenal trauma and the differentiation between an adrenal hemorrhage and a mass. This review addresses the current experience in pediatric CEUS of the kidneys and adrenal glands. By extrapolating the established knowledge for US contrast evaluations in the adult kidney to the pediatric context we can note opportunities for CEUS clinical use in children.

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.

Sonographically Occult Abscesses of the Buttock and Perineum in Children.

BACKGROUND: Ultrasound (US) is used to differentiate abscess from cellulitis. At our institution, we observed children who had purulent fluid obtained after a negative abscess US. We sought to determine the incidence of sonographically occult abscess (SOA) of the buttock and perineum, and identify associated clinical and demographic characteristics. METHODS: Retrospective chart review including children younger than 18 years old presenting to pediatric emergency department with soft tissue infection of the buttock or perineum and diagnostic radiology US read as negative for abscess. We defined SOA as wound culture growing pathogenic organism obtained within 48 hours of the US. Clinical and demographic characteristics included age, sex, race, ethnicity, fever, history of spontaneous drainage, duration of symptoms, previous methicillin resistant Staphylococcus aureus (MRSA) infection, or previous abscess. We used univariate and multivariate logistic regression to assess correlation between these characteristics and SOA. RESULTS: A total of 217 children were included. Sixty-one (28%) children had SOA; 33 of 61 (54%) had incision and drainage within 4 hours of the US. Of children with SOA, 49 (80%) grew MRSA and 12 (20%) grew methicillin-sensitive S. aureus. In univariate analysis, a history of MRSA, symptom duration 4 days or less, age of younger than 4 years, and Hispanic ethnicity increased the odds of having SOA. In multivariate analysis, history of MRSA and duration of 4 days or less were associated with SOA. CONCLUSIONS: Twenty-eight percent of children in our institution with US of the buttock and perineum negative for abscess had clinical abscess within 48 hours, most within 4 hours. History of MRSA and shorter symptom duration increased the odds of SOA.

Deep venous thrombosis in a child with inferior vena cava and renal anomalies: KILT syndrome.

Kidney and inferior vena cava abnormalities with leg thrombosis is a newly described entity in the literature termed KILT (kidney and inferior vena cava (IVC) abnormalities with leg thrombosis) syndrome. We present a case of newly diagnosed KILT syndrome in an 11-year-old girl presenting with pain and problems with ambulation. We also review the few cases of KILT syndrome previously reported in the literature.

Rater reliability of postnatal urinary tract dilation consensus classification.

BACKGROUND: A multidisciplinary urinary tract dilation (UTD) classification system was published in 2014 to standardize definitions and renal/bladder ultrasound image interpretation. OBJECTIVE: To evaluate intra- and inter-rater reliability of this system on postnatal RBUS. MATERIALS AND METHODS: Renal/bladder US of 60 infants (<12 months) with urinary tract dilation were anonymized, retrospectively reviewed and scored twice using the UTD classification system by a pediatric urologist and four pediatric radiologists. Exams included supine and prone images of each kidney. Raters recorded the anterior posterior renal pelvis diameter in each position; and when present calyceal dilation (central and peripheral), ureteral dilation, parenchymal and bladder abnormalities. A UTD score was given to each kidney based on these components. RESULTS: Intraclass correlation (ICC) of anterior posterior renal pelvis diameter measures was 0.99 (P<0.001). Intra-rater reliability for the anterior posterior renal pelvis diameter of each kidney was high, with ICC >0.95 (P<0.001). Inter-rater kappa values for UTD scores of both kidneys ranged from 0.60 to 0.77 (P <0.001). Intra-rater kappa values for UTD scores of both kidneys ranged from 0.74 to 0.92 (P <0.001). Of the six categories comprising the UTD score, discrepancy between raters was highest for interpretation of central and peripheral calyceal dilation. CONCLUSION: Present inter- and intra-rater reliability findings were similar to those previously reported for grading systems for urinary tract dilation. Across these studies, kappa values are generally lower than the 0.8 cut-off advocated for medical measures. Here, calyceal dilation commonly determined the kidney UTD score and was also the source of greatest discrepancy between raters. Improving consistency of calyceal dilation interpretation may improve UTD consensus score reliability.

Contrast-enhanced voiding urosonography (ceVUS) with the intravesical administration of the ultrasound contrast agent Optison™ for vesicoureteral reflux detection in children: a prospective clinical trial.

BACKGROUND: Contrast-enhanced voiding urosonography (ceVUS) is widely used outside the United States to diagnose vesicoureteral reflux (VUR) in children and is highly sensitive while avoiding exposure to ionizing radiation. At the onset of this study, two ultrasound (US) contrast agents were available in the United States. Pediatric safety data for intravenous administration was published for one, Optison™. OBJECTIVE: This study aimed to evaluate the diagnostic performance and safety of ceVUS using Optison™ and compare its diagnostic efficacy with voiding cystourethrogram (VCUG) for VUR detection and grading in children. MATERIALS AND METHODS: The United States Food and Drug Administration and institutional Investigational New Drug authorizations were obtained to conduct a prospective comparative study of ceVUS with Optison™ and VCUG. CeVUS was performed with intravesical administration of 0.2% Optison™/normal saline solution. A standard VCUG followed. Safety assessment included physical examination, and heart rate, pulse oximetry and adverse reactions monitoring before, during and immediately after the examinations. A follow-up questionnaire was completed by telephone 48-h after the studies. RESULTS: Sixty-two pelviureteric units were studied in 30 patients with a mean age of 3.5 years (range: 0.1-17 years) including 21 girls and 9 boys. No severe adverse events occurred. All patients had normal heart rate and blood oxygenation saturation prior to, during and after the studies. At the 48-h follow-up, one patient (3.3%) reported transient dysuria. Taking the VCUG as the reference standard, ceVUS had a sensitivity of 91.7% (95%; confidence interval [CI]: 61.5%-99.8%) and specificity of 98% (95%; CI: 89.4%-99.9%). The concordance between ceVUS and VCUG for VUR detection and grading was 84.3% and 81.8%, respectively. VUR grades were discrepant in 4/11 refluxing pelviureteric units, with VCUG upgrading VUR in 2. CONCLUSION: Detection of VUR with Optison™ ceVUS was comparable to VCUG without exposure to ionizing radiation. CeVUS with Optison™ is a well-tolerated diagnostic procedure with a favorable safety profile.

Ultrasound features of purulent skin and soft tissue infection without abscess.

PURPOSE: Ultrasound (US) aids clinical management of skin and soft tissue infection (SSTI) by differentiating non-purulent cellulitis from abscess. However, purulent SSTI may be present without abscess. Guidelines recommend incision and drainage (I & D) for purulent SSTI, but US descriptions of purulent SSTI without abscess are lacking. METHODS: We retrospectively reviewed pediatric emergency department patients with US of the buttock read as negative for abscess. We identified US features of SSTI with adequate interobserver agreement (kappa > 0.45). Six independent observers then ranked presence or absence of these features on US exams. We studied association between US features and positive wound culture using logistic regression models (significance at p < 0.05). RESULTS: Of 217 children, 35 patients (16%) had cultures positive for pathogens by 8 h after US and 61 patients (32%) had cultures positive by 48 h after US. We found kappa > 0.45 for focal collection > 1.0 cm (κ = 0.57), hyperemia (κ = 0.57), swirling with compression (κ = 0.52), posterior acoustic enhancement (κ = 0.47), and cobblestoning or branching interstitial fluid (κ = 0.45). Only cobblestoning or interstitial fluid was associated with positive wound cultures in logistic regression models at 8 and 48 h. CONCLUSIONS: Cobblestoning or interstitial fluid on US may indicate presence of culture-positive, purulent SSTI in patients without US appearance of abscess. Although our study has limitations due to its retrospective design, this US appearance should alert imagers that the patient may benefit from early I & D.

Ultrasound of the pediatric appendix.

Appendicitis is the most common pediatric surgical emergency. Ultrasound (US) receives the highest appropriate rating scale in children with right lower quadrant pain suspected to have appendicitis. The US exam of the appendix has improved since Puylaert pioneered the technique of graded compression in 1986. In this article, we review ultrasonography of the pediatric appendix as it pertains to the normal appendix, acute appendicitis and the different sonographic manifestations. We also briefly describe technical optimization of image acquisition, common pitfalls and differential diagnoses.

Giant hepatic regenerative nodules in Alagille syndrome.

BACKGROUND: Children with Alagille syndrome undergo surveillance radiologic examinations as they are at risk for developing cirrhosis and hepatocellular carcinoma. There is limited literature on the imaging of liver masses in Alagille syndrome. We report the ultrasound (US) and magnetic resonance imaging (MRI) appearances of incidental benign giant hepatic regenerative nodules in this population. OBJECTIVE: To describe the imaging findings of giant regenerative nodules in patients with Alagille syndrome. MATERIALS AND METHODS: A retrospective search of the hospital database was performed to find all cases of hepatic masses in patients with Alagille syndrome during a 10-year period. Imaging, clinical charts, laboratory data and available pathology were reviewed and analyzed and summarized for each patient. RESULTS: Twenty of 45 patients with confirmed Alagille syndrome had imaging studies. Of those, we identified six with giant focal liver masses. All six patients had large central hepatic masses that were remarkably similar on US and MRI, in addition to having features of cirrhosis. In each case, the mass was located in hepatic segment VIII and imaging showed the mass splaying the main portal venous branches at the hepatic hilum, as well as smaller portal and hepatic venous branches coursing through them. On MRI, signal intensity of the mass was isointense to liver on T1-weighted sequences in four of six patients, but hyperintense on T1 in two of six patients. In all six cases, the mass was hypointense on T2- weighted sequences. The mass post-contrast was isointense to adjacent liver in all phases in five the cases. Five out of six patients had pathological correlation demonstrating preserved ductal architecture confirming the final diagnosis of a regenerative nodule. CONCLUSION: Giant hepatic regenerative nodules with characteristic US and MR features can occur in patients with Alagille syndrome with underlying cirrhosis. Recognizing these lesions as benign giant hepatic regenerative nodules should, thereby, mitigate any need for intervention.

Common and uncommon applications of bowel ultrasound with pathologic correlation in children.

OBJECTIVE: The purpose of this article is to describe the indications and techniques for bowel ultrasound for inflammatory bowel disease and other common and uncommon entities and describe and illustrate their imaging appearances, including endoscopic or surgical correlation. CONCLUSION: Ultrasound is a useful tool for the evaluation of inflammatory bowel disease and many other bowel diseases. Radiologists must become familiar with the full potential of ultrasound in the evaluation of the bowel in children because the need for alternative radiation-free imaging techniques continues to grow.

Prevalence of tubo-ovarian abscess in adolescents diagnosed with pelvic inflammatory disease in a pediatric emergency department.

OBJECTIVES: The rate of tubo-ovarian abscess (TOA) in adolescents with pelvic inflammatory disease (PID) is reported to range from 17% to 20%. However, no reports have focused specifically on the adolescent patient presenting to the emergency department (ED), regardless of whether they are treated in the inpatient or outpatient setting. Recent changes in the 2002 Centers for Disease Control and Prevention (CDC) Guidelines for the Treatment of Sexually Transmitted Diseases and sexually transmitted infection screening programs are likely to have impacted both the prevalence of PID and the rates of its complications, particularly TOA. Given that most patients with PID are treated as outpatients, it is imperative to accurately assess the prevalence of TOA in this population. Therefore, we sought to determine the rate of TOA in female adolescents diagnosed with PID in a large urban pediatric ED. METHODS: We performed a retrospective medical record review to assess the prevalence of TOA in adolescents diagnosed with PID in the ED by an attending physician in pediatric emergency medicine. All cases were identified on the basis of the clinical criteria from the 2002 CDC Guidelines for the Treatment of Sexually Transmitted Diseases. Data collected included historical and physical examination findings, and laboratory and radiological imaging results. RESULTS: Three (2.4%; 95% confidence interval, 0.5-6.7) of 127 patients diagnosed with PID in the ED who had imaging or clinical follow-up were also found to have a TOA. The mean age of the patients was 16 years. Most patients (89%) had imaging studies performed within 24 hours; most of these studies (97%) were pelvic ultrasounds. Eleven patients did not have imaging but had clinical follow-up within 72 hours. Four patients were diagnosed with PID during the study period and were lost to follow-up. CONCLUSION: The rate of TOA in adolescents diagnosed with PID in an urban pediatric ED is much lower than the rates previously reported in adolescents. This lower prevalence may be attributed to the broader 2002 CDC guidelines for diagnosing PID. In addition, community-based screening programs for Chlamydia trachomatis and Neisseria gonorrhoeae may help to identify young women at risk for developing PID earlier in the course of infection.

Posttransplantation lymphoproliferative disorder in pediatric recipients of solid organ transplants: timing and location of disease.

OBJECTIVE: The objective of our study was to correlate the location of radiologic presentation and time to onset of posttransplantation lymphoproliferative disorder (PTLD) with the allograft type received in a population of pediatric heart, lung, liver, kidney, and bone marrow transplant recipients. CONCLUSION: Symptomatic PTLD in children manifests earliest in lung recipients and can involve any organ system. However, PTLD in the thorax is most common after lung transplantation, and PTLD in the abdomen most commonly follows kidney transplantation.

Cross-fused ectopic multicystic dysplastic kidney with associated ureterocele.

We describe a case of the unique congenital anomaly of cross-fused ectopic multicystic dysplastic kidney with associated ureterocele and demonstrate the usefulness of magnetic resonance imaging in fetal imaging.