Insights into Kidney Dysplasia in Duplex Kidneys: From Radiologic Diagnosis to Histopathologic Understanding.

Duplex kidney is a urinary tract anomaly commonly associated with a wide range of primary and secondary parenchymal structural abnormalities. We present a unique comparison of US and MRI findings with histopathology following partial resection of duplex kidneys due to nephropathy. We examined a group of 21 children with duplex kidneys who were qualified for heminephrectomy (24 kidney units (KU)). All patients underwent US and MRI prior to the surgery. The imaging results were compared with histopathologic findings. In 21/24 KU, dysplastic changes were found on histopathology, including all with obstructive nephropathy and 7/10 specimens with refluxing uropathy. The loss of corticomedullary differentiation on US and increased signal on T2-weighted images (T2WI) on MRI were the imaging findings that best correlated with fibrosis. In children with megaureter, there were no statistical differences in histopathological findings between primary megaureter, megaureter with ureterocele, and megaureter with ectopia (p > 0.05). The extent of dysplasia of the affected pole correlated negatively with residual function in MRI. Kidney dysplasia and inflammation in the kidney with obstructive nephropathy are the most important histopathologic findings of this study. US is a valuable screening tool, and MRI enables morphologic and functional assessments of the nephropathy in duplex kidneys.

Intravenous administration of ultrasound contrast to critically ill pediatric patients.

BACKGROUND: The off-label use of contrast-enhanced ultrasound has been increasingly used for pediatric patients. OBJECTIVE: The purpose of this retrospective study is to report any observed clinical changes associated with the intravenous (IV) administration of ultrasound contrast to critically ill neonates, infants, children, and adolescents. MATERIALS AND METHODS: All critically ill patients who had 1 or more contrast-enhanced ultrasound scans while being closely monitored in the neonatal, pediatric, or pediatric cardiac intensive care units were identified. Subjective and objective data concerning cardiopulmonary, neurological, and hemodynamic monitoring were extracted from the patient's electronic medical records. Vital signs and laboratory values before, during, and after administration of ultrasound contrast were obtained. Statistical analyses were performed using JMP Pro, version 15. Results were accepted as statistically significant for P-value<0.05. RESULTS: Forty-seven contrast-enhanced ultrasound scans were performed on 38 critically ill patients, 2 days to 17 years old, 19 of which were female (50%), and 19 had history of prematurity (50%). At the time of the contrast-enhanced ultrasound scans, 15 patients had cardiac shunts or a patent ductus arteriosus, 25 had respiratory failure requiring invasive mechanical oxygenation and ventilation, 19 were hemodynamically unstable requiring continual vasoactive infusions, and 8 were receiving inhaled nitric oxide. In all cases, no significant respiratory, neurologic, cardiac, perfusion, or vital sign changes associated with IV ultrasound contrast were identified. CONCLUSION: This study did not retrospectively identify any adverse clinical effects associated with the IV administration of ultrasound contrast to critically ill neonates, infants, children, and adolescents.

Prenatal Presentation of a Covered Cloacal Exstrophy Variant; Early Diagnostic Challenges Within the Broad Spectrum of the Exstrophy-Epispadias Complex.

There is a broad range of variant phenotypes that can occur within the bladder exstrophy and epispadias complex spectrum. Accurate prenatal detection helps prepare families and to coordinate subspecialty resources. Here, we present the case of a patient with prenatally diagnosed patient with covered cloacal exstrophy variant along with four additional cases illustrating the nonlinear spectrum from isolated epispadias to cloacal exstrophy. Given the rarity of these variants overall and of each subtype within the spectrum, there is a need for long-term multi-institutional outcomes data to improve detection, characterization, and prognostication for these patients.

Safety of Ultrasound Contrast Agents in Pediatric Patients With Sickle Cell Disease and Trait.

Ultrasound contrast agent (UCA) use is increasing. Recent isolated reports observed a rise in pain-related adverse events with the intravenous administration of the UCA Definity in adults with sickle cell disease. To date, no studies have investigated the incidence of similar adverse events with UCA Lumason or Optison. We describe our experience regarding the safety of Lumason and Optison in children with sickle cell disease and trait who underwent contrast-enhanced ultrasound exams in our department with intravenous, intravesical, and other intracavitary routes. No pain-related or other adverse events were observed in this pediatric population with any route of UCA administration.

Utilizing RENAL nephrometry in pediatric patients undergoing nephron-sparing surgery for renal tumors: A single-institutional cohort.

INTRODUCTION: RENAL Nephrometry is a complexity score validated in adults with renal tumors and describes the likelihood of complication after partial nephrectomy (PN). Utilization in pediatrics has been limited. Thus, our goal is to quantify inter-rater agreement as well as determine how scores correlate with outcomes. We hypothesize that the RENAL Nephrometry Score is reproducible in children with renal tumors and is related to perioperative and post-operative complications. METHODS: All pediatric patients who underwent PN for a renal mass from 2006 to 2019 were identified. Patient data, operative details, and outcomes were aggregated. Pre-operative CT/MR imaging was anonymized and scored by 2 pediatric radiologists and 2 pediatric urologists using RENAL Nephrometry metrics. Statistical analysis utilized Fleiss' kappa and the intraclass correlation coefficient (ICC). Comparative analyses were performed based on Nephrometry Score <9 and ≥ 9. RESULTS: 28 patients undergoing 33 PN were identified. Median age at surgery was 3.2 years (IQR 1.8-4.0). There is moderate-good agreement across scorers on the domains of RENAL Nephrometry Score, with the lowest agreement noted for anterior vs posterior tumors. Comparing patients with scores <9 and ≥ 9, there was increased operative time (357 vs 267 min, p = 0.003) and LOS for those with a higher score, but no difference in the incidence of 30-day complications. CONCLUSION: RENAL Nephrometry Score is an easily reproducible complexity score for renal tumors in pediatric patients. Higher scores are associated with increased length of stay and estimated blood loss but not complications. Reporting of nephrometry scores in future publications on pediatric renal tumors should become standard in the literature.

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.

Pediatric Genitourinary 3D Modeling and Printing Using Multiphase Postcontrast Imaging Segmentation.

OBJECTIVE: To describe the development and implementation of a process for creating accurate Pediatric genitourinary 3D modeling and printing with multiphase postcontrast imaging for surgical planning. MATERIALS AND METHODS: Additive manufacturing and 3D model present opportunities to support clinical planning, this manuscript's specific process and considerations for creating pediatric genitourinary 3D modeling to support urology. The process for creating the 3D models and prints covers 3 key aspects from image acquisition, imaging review and selection, and segmentation and modification (as needed). Each step is outlined with the key roles and procedures. RESULTS: The described case had digital and printed models prepared with references to the optimized imaging sequence for 3D modeling of Pediatric genitourinary. Case shared include complex genitourinary reconstruction and Kideny with Wilms tumors. CONCLUSION: The processes described have become a standard of practice for complex kidney tumors and exstrophy planning. The team continues to work on ever-changing improvements to make the best possible models to support clinical and surgical planning.

Assessment of fluid removal using ultrasound, bioimpedance and anthropometry in pediatric dialysis: a pilot study.

BACKGROUND: Fluid overload is associated with morbidity and mortality in children receiving dialysis. Accurate clinical assessment is difficult, and using deuterium oxide (D2O) to measure total body water (TBW) is impractical. We investigated the use of ultrasound (US), bioimpedance spectroscopy (BIS), and anthropometry to assess fluid removal in children receiving maintenance hemodialysis (HD). METHODS: Participants completed US, BIS, and anthropometry immediately before and 1-2 h after HD for up to five sessions. US measured inferior vena cava (IVC) diameter, lung B-lines, muscle elastography, and dermal thickness. BIS measured the volume of extracellular (ECF) and intracellular (ICF) fluid. Anthropometry included mid-upper arm, calf and ankle circumferences, and triceps skinfold thickness. D2O was performed once pre-HD. We assessed the change in study measures pre- versus post-HD, and the correlation of change in study measures with percent change in body weight (%∆BW). We also assessed the agreement between TBW measured by BIS and D2O. RESULTS: Eight participants aged 3.4-18.5 years were enrolled. Comparison of pre- and post-HD measures showed significant decrease in IVC diameters, lung B-lines, dermal thickness, BIS %ECF, mid-upper arm circumference, ankle, and calf circumference. Repeated measures correlation showed significant relationships between %∆BW and changes in BIS ECF (rrm =0.51, 95% CI 0.04, 0.80) and calf circumference (rrm=0.80, 95% CI 0.51, 0.92). BIS TBW correlated with D2O TBW but overestimated TBW by 2.2 L (95% LOA, -4.75 to 0.42). CONCLUSION: BIS and calf circumference may be helpful to assess changes in fluid status in children receiving maintenance HD. IVC diameter, lung B-lines and dermal thickness are potential candidates for future studies.

Ultrasound-Estimated Bladder Weight Correlates With Videourodynamic Studies in Neurogenic Bladder Dysfunction.

PURPOSE: This retrospective study was designed to evaluate which lower urinary tract ultrasound parameter(s) could predict the results of invasive urodynamic testing which are the current reference standard in the evaluation of bladder dysfunction in children with spina bifida. MATERIALS AND METHODS: Fifty eight children with spina bifida undergoing video urodynamic evaluation and a renal bladder ultrasound as their standard of care were evaluated. Quantitative and qualitative ultrasound parameters were then correlated with the videourodynamic study results which served as the reference standard. RESULTS: For bladders with ending storage pressures above 15 cm H2 O, there were increases in these ultrasound measured parameters: 1) bladder mass (P = .00019), 2) bladder/body mass ratio (P = .0059), and 3) wall thickness (P = .01). We defined the storage cost as the final storage pressure divided by the percentage of expected bladder capacity attained. These data were analyzed to compute receiver operating curves with assuming end storage pressures cutoff points of 15, 20, 30, and 40 cm H2 O. The optimal area under the curve was found for a bladder weight of 65 g and a pressure cutoff of 30 cm H2 O with a sensitivity of 75% with a specificity of 84%. CONCLUSION: Bladder weight is independent of luminal volume, can be normalized to body weight, and may serve as a clinically valuable tool for noninvasive screening to define a subset of patients with neurogenic bladder with a higher likelihood of having abnormal videourodynamic results.

Magnetic resonance urography: a practical approach to preparation, protocol and interpretation.

Magnetic resonance urography (MRU) is an important MRI application that provides noninvasive comprehensive morphological and functional evaluation of the kidneys and urinary tract. It can be used to assess congenital anomalies of the kidney and urinary tract, which often present as urinary tract dilation. In children, MRU allows for high tissue contrast and high spatial resolution without requiring ionizing radiation. Magnetic resonance urography requires patient preparation in the form of pre-examination intravenous hydration, placement of a urinary catheter, and the administration of diuretics at the time of the exam. The imaging protocol is based on T2-weighted images for anatomical assessment and dynamic post-contrast images for functional evaluation. These images are then used to generate quantitative and graphic results including contrast transit and excretion time as well as to calculate differential renal function. This review focuses on a simple approach to pediatric MRU acquisition and interpretation based on clinical cases and the authors' experience.

Microbubbles in the belly: optimizing the protocol for contrast-enhanced ultrasound of the pediatric abdomen.

Intravenous contrast-enhanced ultrasound (CEUS) can serve as a diagnostic or problem-solving tool in pediatric imaging. CEUS of abdominal solid organs has been reported for a number of indications. The approach to the examination broadly falls into two categories: evaluation of a focal lesion or surveillance of an organ or organs for lesions or perfusion abnormalities. A consistent, technical imaging protocol for both of these clinical scenarios facilitates integration of routine use of CEUS in an imaging department. Here we review the CEUS imaging protocols for abdominal organs in children, including technical and solid-organ-specific considerations.

Imaging of pediatric ovarian tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

Ovarian tumors in children are uncommon. Like those arising in the adult population, they may be broadly divided into germ cell, sex cord, and surface epithelium subtypes; however, germ cell tumors comprise the majority of lesions in children, whereas tumors of surface epithelial origin predominate in adults. Diagnostic workup, including the use of imaging, requires an approach that often differs from that required in an adult. This paper offers consensus recommendations for imaging of pediatric patients with a known or suspected primary ovarian malignancy at diagnosis and during follow-up.

Imaging of pediatric testicular tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

Primary intratesticular tumors are uncommon in children, but incidence and risk of malignancy both sharply increase during adolescence. Ultrasound is the mainstay for imaging the primary lesion, and cross-sectional modalities are often required for evaluation of regional or distant disease. However, variations to this approach are dictated by additional clinical and imaging nuances. This paper offers consensus recommendations for imaging of pediatric patients with a known or suspected primary testicular malignancy at diagnosis and during follow-up.

A novel quantitative approach to evaluate femoral head perfusion by contrast-enhanced ultrasound: A pilot study in infants with developmental dysplasia of the hip.

Avascular necrosis (AVN) is a major morbidity that can occur after surgical reduction of a hip with developmental dysplasia. Early detection of changes in femoral head perfusion during surgery may help detect a hip at risk for AVN and guide intraoperative management. Contrast-enhanced ultrasound (CEUS) can be employed for visualization of femoral head perfusion. In this study we evaluate a quantitative CEUS technique to assess femoral head perfusion pre- and post-surgical reduction. CEUS images were obtained following a bolus injection of an ultrasound contrast agent, prior to and again following surgical reduction and casting. An image processing technique called delta projection was used to quantify hip perfusion, measuring peak enhancement (PE) and perfusion index (PI). We analyzed CEUS images of the hips of eight patients, including seven females, whose ages ranged from 4 months to 1 year. In five hips, perfusion increased following surgery, with a mean pre-surgery PE of 6.7 ±2.5(± SE) and PI of 10.5 ±6.3; and a post-reduction PE of 13.1±6.1 (p=0.07) and PI of 14.2 ±6.2 (p=0.008). The change in contrast visualization was observed to be greater within the central aspect of the cartilaginous femoral epiphysis. The proposed technique can quantify pre- and post-surgical perfusion changes on CEUS images in patients with developmental dysplasia. This quantitative technique may provide a more objective and accurate assessment of changes in femoral head perfusion that may have the potential to be indicative of the risk of developing AVN.

Added value of gadolinium-based contrast agents for magnetic resonance evaluation of adnexal torsion in girls.

PURPOSE: Ultrasound is the first-line imaging modality to evaluate adnexa in girls with clinical suspicion of torsion. Patients with equivocal ultrasound findings can undergo MRI for better delineation of adnexal pathology. Here, we assess the utility of intravenous contrast in MRI evaluation of adnexal torsion in children. METHODS: Two pediatric radiologists (R1, R2) retrospectively reviewed 198 pelvic MRI exams in 172 girls (median age 15 years). Each MRI was reviewed twice. The first review included pre-contrast images only. A second review, at least 1 month later, included both pre- and post-contrast images. Readers concluded if findings were suspicious for torsion or not. Readers' findings were compared to each other's and to surgical and MRI reports and clinical course. RESULTS: 198 MRI exams yielded 354 evaluable ovaries. Surgical and pathological reports were available for 47 patients. 11 patients had adnexal torsion. Both readers accurately diagnosed acutely torsed ovaries during pre- and post-contrast reviews (n = 4). However, readers disagreed on torsed paraovarian cysts (n = 4) and chronically/intermittently torsed ovaries (n = 3). In 21 non-torsed ovaries that had lesions, one or both readers concluded that there were pre-contrast features of torsion. In this set with ovarian lesions, contrast helped readers to correctly conclude no torsion (R1 = 8, R2 = 6) more commonly than to incorrectly conclude torsion (1 each), improving post-contrast specificity for each reader. CONCLUSIONS: Post-contrast sequences did not provide additional benefit in evaluating acutely torsed ovaries but helped in excluding torsion in patients with adnexal lesions. Therefore, contrast administration should be individualized, potentially reserved only for those with abnormal ultrasound or pre-contrast images.

Contrast-enhanced ultrasound of adrenal hemorrhage: a helpful problem solving tool.

AIMS: A focal lesion in the region of the adrenal gland in a newborn often requires further assessment. Ultrasound (US) is the initial imaging method of choice in young children as it does not use radiation or require sedation and it has excellent spatial resolution. In this case series, we present contrast-enhanced ultrasound (CEUS) as a problem-solving tool in the evaluation of neonatal adrenal lesions. MATERIAL AND METHODS: The imaging and medical records of five patients with adrenal lesions were retrospectively reviewed. All patients underwent US as an initial examination and all had US follow-up. Additionally, two patients had MRI examinations. CEUS was performed in all patients as a follow up examination. The enhancement characteristics of the adrenal masses on CEUS were analyzed with the use of VueBox software. In addition, qualitative analysis of the cine loops for the presence of vascularization within the lesions was performed by consensus between two radiologists. RESULTS: The presence of an adrenal hematoma was correctly detected and characterized by CEUS in all five cases using VueBox perfusion analysis. Adrenal hematomas had no internal perfusion and flat time intensity curves. CONCLUSION: The quantitative and qualitative CEUS assessment of the mass can distinguish hemorrhage from a malignant lesion. Based on our findings, CEUS could serve as an alternative diagnostic tool to magnetic resonance imaging in the diagnosis of slowly resolving NAH lesions.

Ultrasound shear wave elastography cannot discriminate between low- and high-pressure neurogenic bladders.

BACKGROUND: Patients with neurogenic bladders are monitored with renal bladder ultrasounds and video urodynamics studies (VUDS) to assess upper urinary tract injury. Ultrasound shear wave elastography (US-SWE) can assess tissue stiffness. If bladder compliance is affected by bladder wall fibrosis and stiffening, then high-pressure bladders may be detectable by US-SWE therefore reducing the need for VUDS in some patients. OBJECTIVE: To determine if US-SWE can differentiate between low- and high-pressure bladders and hence be used for noninvasive assessment of neurogenic bladder in children. STUDY DESIGN: Prospective study of patients with neurogenic bladder undergoing clinically indicated VUDS between February and July of 2017. During VUDS, bladder wall US-SWE was measured at different filling percentages of estimated bladder capacity (EBC). The bladders were divided into cohorts according to the detrusor muscle pressure (Pdet) reached at the maximum bladder capacity: normal (1 to <15 cmH2O) and abnormal (≥15 cmH2O) pressure. T-test was used to compare elastography values at different bladder volumes and Pdet; (statistical significance set at p < 0.05). RESULTS: 30/31 enrolled children completed the protocol. With an empty bladder, as well as at all other bladder volumes, no relationship was observed between Pdet and mean SWE of the anterior or posterior bladder wall. At maximum bladder capacity, there was no difference between mean SWE values of the anterior or posterior bladder walls in those with normal pressure, 2.97 m/s (SD ± 0.82) and 1.96 m/s (SD ± 0.75), compared to those with abnormal pressures 3.08 m/s (SD ± 0.84) and 2.39 m/s (SD ± 0.96), p = 0.75 and p = 0.2, respectively. DISCUSSION: We found no difference between SWE values of either the anterior or posterior bladder wall in neurogenic bladders with normal and abnormal filling pressures measured during VUDS. Our study differs from previously reported studies with more positive results in that our cut-off for abnormal bladder pressure was (Pdet ≥15 cmH2O). This is lower than the more commonly used leak point pressure of 40 cmH2O because our practice is to intervene earlier. Moreover, SWE would be most useful if it can identify changes before the bladder has reached such severe conditions, to allow for early intervention. Additional differences between ours and other studies include US manufacturer and younger age of the participating children. CONCLUSIONS: US-SWE, while feasible, was not able to discriminate between low- and high-pressure bladders. Moreover, US-SWE did not show significant correlation with the current gold standard, VUDS.

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.