What is this bump in my neck? Ultrasonographic evaluation of pediatric neck masses.

Neck masses are common in pediatric patients, with benign etiologies such as congenital or inflammatory lesions accounting most of these masses. Anatomic location (most important), clinical history, and the appearance in ultrasonography (US) are helpful clues to narrow down differential diagnosis. Because of widespread availability, lack of ionizing radiation, and no need for sedation or contrast administration, US is the preferred initial modality for the evaluation. Further evaluation with cross-sectional imagings is needed for more extensive lesions with trans-spatial extension or suspicion of intrathoracic or retropharyngeal extension. This review will focus on US appearance and clinical presentation of masses of the neck in children, to enable radiologist to arrive at a reasonable differential diagnosis. We also briefly discuss more complex pathologies that need to be evaluated with cross-sectional modalities such as CT scan and magnetic resonance imaging.

Postviral Gastroparesis Associated With SARS-CoV-2 Infection in a Pediatric Patient.

Postviral gastroparesis has been described in children, but it has not yet been attributed to SARS-CoV-2 infection. Our case report describes a teenager with abdominal pain, early satiety, and vomiting who likely had an asymptomatic SARS-CoV-2 infection 2 months before presentation. Through investigation of epidemiologic links, antibody testing, and clinical course, it is hypothesized that her significant reduction in gastric emptying was due to postviral gastroparesis secondary to SARS-CoV-2. She was treated with supportive care and prokinetic agents. The patient demonstrated symptom resolution and near normalization of gastric emptying by the time of 1 month follow up.

Development of a tool to aid the radiologic technologist using augmented reality and computer vision.

This technical innovation describes the development of a novel device to aid technologists in reducing exposure variation and repeat imaging in computed and digital radiography. The device consists of a color video and depth camera in combination with proprietary software and user interface. A monitor in the x-ray control room displays the position of the patient in real time with respect to automatic exposure control chambers and image receptor area. The thickness of the body part of interest is automatically displayed along with a motion indicator for the examined body part. The aim is to provide an automatic measurement of patient thickness to set the x-ray technique and to assist the technologist in detecting errors in positioning and motion before the patient is exposed. The device has the potential to reduce the incidence of repeat imaging by addressing problems technologists encounter daily during the acquisition of radiographs.

Technique for Performing Lumbar Puncture in Microgravity Using Portable Radiography.

INTRODUCTION: Visual Impairment and Intracranial Pressure Syndrome (VIIP) has caused symptomatology during and after long duration missions on the International Space Station (ISS). Only indirect measurements of intracranial pressure (ICP), such as ultrasound, have been performed on ISS. Discussion and interest has happened at NASA about performing lumbar puncture (LP) in microgravity. Only the "blind" palpation approach and the ultrasound-assisted approach have been discussed. This article, as proof of concept, discusses the possibility of portable radiography to assist lumbar punctures in microgravity. METHOD: An anthropomorphic radiological phantom of an adult lumbar spine was made containing a fluid-filled space in the spinal canal with a latex membrane which simulated the dural sac and cerebrospinal fluid. A portable direct-digital radiography system with wireless transmitting image receptor and screen was used to perform image-guided lumbar puncture. Using the same equipment and technique, this procedure was then performed on a cadaver for final proof of concept. RESULTS: Technical success was achieved in all approaches on the first try without needle redirection. There was no difference between the cadaver model and the phantom model in terms of difficulty in reaching the fluid space or visually confirming needle location. DISCUSSION: Portable radiography via proof of concept has the potential to guide lumbar puncture while minimizing volume and mass of equipment. This could be ideal for assisting in performing lumbar puncture in microgravity, as this is the standard of care on Earth for difficult or failed "blind" lumbar punctures. Lerner DJ, Parmet AJ, Don S, Shimony JS, Goyal MS. Technique for performing lumbar puncture in microgravity using portable radiography. Aerosp Med Hum Perform. 2016; 87(8):745-747.

ALARA: Impact of Practice Quality Improvement Initiative on Dose Reduction in Pediatric Voiding Cystourethrogram.

OBJECTIVE: This practice quality improvement study of pediatric voiding cystourethrogram (VCUG) investigated the adequacy of substituting last-image capture for digital-spot images and dose reduction when this substitution was implemented and determined correlations between dose-area products (DAPs), patient ages, and fluoroscopy times. MATERIALS AND METHODS: The study consisted of three phases: phase 1 documented baseline data and evaluated diagnostic accuracy between last-image capture and digital-spot images. Phase 2 documented the change in dose after substituting last-image capture for digital-spot images. Phase 3 measured doses 3 years later. Each phase-1 VCUG study was segregated into two image sets: last-image capture and digital-spot images. Three radiologists graded vesicoureteral reflux on each side using the international grading scale. Weighted kappa statistics assessed grading differences between image sets. Patient age, fluoroscopy time, and DAP were assessed with parametric and nonparametric statistics. RESULTS: Seventy-seven, 65, and 71 VCUGs were assessed for phases 1, 2, and 3, respectively. Weighted κ = 0.94-0.99 indicated nearly perfect agreement between last-image-capture and digital-spot-image interpretations. For phase 2, last-image capture was substituted for digital-spot images for early-filling and voiding images. DAP decreased for all three radiologists (p ≤ 0.01). Five of six (83%) correlations between DAP and age were higher than the correlations between DAP and fluoroscopy time. The dose remained significantly lower in phase 3. CONCLUSION: This project changed practice by substituting last-image capture for digital-spot images without affecting vesicoureteral reflux grading while reducing radiation exposure. Monitoring DAP is a better assessment of radiation exposure than is fluoroscopy time.

The role of PET/CT in assessing pulmonary nodules in children with solid malignancies.

OBJECTIVE. The purpose of this article is to assess the feasibility and utility of PET/CT in distinguishing benign from malignant pulmonary nodules in patients with solid childhood malignancies. SUBJECTS AND METHODS. This prospective study was conducted between March 2008 and August 2010. We enrolled 25 subjects 21 years old or younger with solid childhood malignancies and at least one pulmonary nodule measuring 0.5-3.0 cm. PET/CT was performed within 3 weeks of diagnostic chest CT. Three panels of three reviewers each reviewed diagnostic CT only (panel 1), PET/CT only (panel 2), or diagnostic CT and PET/CT concurrently (panel 3) and predicted each nodule's histologic diagnosis as benign, malignant, or indeterminate. Interreviewer agreement was assessed with the kappa statistic. Using nodule biopsy or clinical follow-up as reference standards, the sensitivity, specificity, and accuracy for each panel was assessed. Logistic regression was used to assess the nodule's maximum standardized uptake value (SUVmax) association with its histologic diagnosis. RESULTS. There were 75 nodules with a median size of 0.74 cm (range, 0.18-2.38 cm); 48 nodules were malignant. Sensitivity was 85% (41/48) for panel 1, 60% (29/48) for panel 2, and 67% (32/48) for panel 3. All panels had poor specificities. Interreviewer agreement was moderate for panel 1 (0.43) and poor for panels 2 (0.22) and 3 (0.33). SUVmax was a significant predictor of histologic diagnosis (p = 0.004). CONCLUSION. PET/CT assessment of pulmonary nodules is feasible in children with solid malignancies but may not reliably improve our ability to predict a nodule's histologic diagnosis. The SUVmax may improve the performance of PET/CT in this setting.

The Image Gently pediatric digital radiography safety checklist: tools for improving pediatric radiography.

Transition from film-screen to digital radiography requires changes in radiographic technique and workflow processes to ensure that the minimum radiation exposure is used while maintaining diagnostic image quality. Checklists have been demonstrated to be useful tools for decreasing errors and improving safety in several areas, including commercial aviation and surgical procedures. The Image Gently campaign, through a competitive grant from the FDA, developed a checklist for technologists to use during the performance of digital radiography in pediatric patients. The checklist outlines the critical steps in digital radiography workflow, with an emphasis on steps that affect radiation exposure and image quality. The checklist and its accompanying implementation manual and practice quality improvement project are open source and downloadable at www.imagegently.org. The authors describe the process of developing and testing the checklist and offer suggestions for using the checklist to minimize radiation exposure to children during radiography.

Image gently campaign back to basics initiative: ten steps to help manage radiation dose in pediatric digital radiography.

OBJECTIVE: The purpose of this review is to summarize 10 steps a practice can take to manage radiation exposure in pediatric digital radiography. CONCLUSION: The Image Gently campaign raises awareness of opportunities for lowering radiation dose while maintaining diagnostic quality of images of children. The newest initiative in the campaign, Back to Basics, addresses methods for standardizing the approach to pediatric digital radiography, highlighting challenges related to the technology in imaging of patients of widely varying body sizes.

New exposure indicators for digital radiography simplified for radiologists and technologists.

OBJECTIVE: The purpose of this article is to educate radiologists and technologists about the clinically relevant portion of the new digital radiography standards. CONCLUSION: Both the International Electrotechnical Commission (IEC standard 62494-1) and the American Association of Physicists in Medicine (AAPM Task Group 116) have developed similar standards for monitoring exposure in digital radiography to eliminate proprietary and confusing terminology. Radiologists and technologists will need to learn three new terms--exposure index, target exposure index, and deviation index--to understand the new standards.

Image Gently: progress and challenges in CT education and advocacy.

Significant progress has been made in radiation protection for children during the last 10 years. This includes increased awareness of the need for radiation protection for pediatric patients with international partnerships through the Alliance for Radiation Safety in Pediatric Imaging. This paper identifies five areas of significant progress in radiation safety for children: the growth of the Alliance; the development of an adult radiation protection campaign Image Wisely™; increased collaboration with government agencies, societies and the vendor community; the development of national guidelines in pediatric nuclear medicine, and the development of a size-based patient dose correction factor by the American Association of Physicists in Medicine, Task Group 204. However, many challenges remain. These include the need for continued education and change of practice at adult-focused hospitals where many pediatric CT exams are performed; the need for increased emphasis on appropriateness of pediatric imaging and outcomes research to validate the performance of CT studies, and the advancement of the work of the first pediatric national dose registry to determine the "state of the practice" with the final goal of establishing ranges of optimal CT technique for specific scan indications when imaging children with CT.

Approaches to promotion and implementation of action on Radiation Protection for children.

The Radiation Protection in Medicine conference, reviewed in this journal supplement, outlined nine strategies to promote radiation protection for patients. The Alliance for Radiation Safety in Pediatric Imaging has focused its work on three of those areas: creating awareness of the need and opportunities for radiation protection for children; developing open-source educational materials for medical professionals and parents on this critical topic for improved patient safety and communication; and lastly, advocating on behalf of children with industry, government and regulatory bodies to improve equipment design and safety features, standardisation of nomenclature and displays of dose reports across vendor platforms that reflect the special considerations of children.

Pediatric digital radiography summit overview: state of confusion.

On Feb. 4, 2010, the Alliance for Radiation Safety in Pediatric Radiology held a Pediatric Digital Radiography Summit. The goal was for radiologists, radiologic technologists, medical physicists, and vendor representatives, including engineers, medical physicists and education specialists, to discuss the challenges to achieving the ALARA (as low as reasonably achievable) principle in pediatric digital radiography and to lay the groundwork for overcoming these obstacles. This article focuses on the state of confusion that exists for radiologists and radiologic technologists who use digital radiography equipment. Radiologists might have a difficult time accepting lower dose (noisy images), and radiologic technologists might respond by increasing patient exposures, which results in excessive patient doses. For reporting exposures, vendors have a history of using proprietary terms that confuse users. In addition, technical parameters cannot be easily exported for quality assurance, and there is no national standard for digital radiography. Presentations in this minisymposium focus on suggestions for the cooperative development of new technical standards, education and training to improve the quality of digital radiography in pediatric patients and promote radiation protection for children.

Comparison of Haller index values calculated with chest radiographs versus CT for pectus excavatum evaluation.

BACKGROUND: Pectus excavatum is a common chest wall anomaly in children. Pre-operative imaging for pectus excavatum is performed with CT, which is used to calculate the Haller index to determine the severity of pectus excavatum. OBJECTIVE: To determine the correlation between Haller index values calculated with two-view chest radiographs and those calculated with CT and to determine, with CT as the reference standard, the diagnostic performance of radiographic Haller index for identifying cases that meet imaging criteria for surgical correction of pectus excavatum. MATERIALS AND METHODS: For the period 2001-2009, our radiology information system was searched to identify all children who had undergone CT for Haller index calculation. Children who had also undergone two-view chest radiography (CXR) within 6 months of the CT were included in this retrospective study. Two radiologists independently calculated CT Haller index and radiographic Haller index. Data distributions were tested for normality with the Shapiro-Wilk W test. The associations between CT Haller index and radiographic Haller index were determined with the Spearman coefficient of rank correlation. Differences between CT Haller index and radiographic Haller index were tested with the Wilcoxon signed rank test. Haller index values were dichotomized into positive (>3.2) and negative (≤3.2) cases. Using CT as the reference standard, the sensitivity, specificity, and accuracy of radiographic Haller index in identifying children who meet imaging criteria for surgery were calculated. RESULTS: CT and CXR for evaluation of pectus excavatum were available for 32 children (25 male; median age 14.5 years). With CT, the median Haller indices for observers 1 and 2 were 3.4 and 3.5 and with CXR 3.5 and 3.5. There were statistically significant correlations between the radiographic Haller index and CT Haller index estimated by the two observers [Spearman correlation coefficient (95% confidence interval) for observer 1 = 0.71 (0.48-0.85, P < 0.01) and for observer 2 = 0.77 (0.52-0.88, P < 0.01)]. A statistically significant correlation was found between the radiographic Haller index calculated by the two observers [Spearman correlation coefficient = 0.98 (0.95-0.99, P < 0.01)]. Using CT Haller index as the reference standard, radiographic Haller index had a sensitivity of 0.95 (0.75-0.99), specificity of 0.75 (0.43-0.94), and accuracy of 0.88 (0.72-0.95) for observer 1, and a sensitivity of 0.95 (0.75-0.99), specificity of 0.67 (0.35-0.90), and accuracy of 0.84 (0.68-0.93) for observer 2. CONCLUSION: Radiographic Haller index correlates strongly with CT Haller index, has good interobserver correlation, and has a high diagnostic accuracy for pre-operative evaluation of pectus excavatum. We suggest that a CT of the chest is not required for pre-operative evaluation of pectus excavatum, and a two-view chest radiograph is sufficient for preoperative imaging of pectus excavatum.

Validation of CT dose-reduction simulation.

The objective of this research was to develop and validate a custom computed tomography dose-reduction simulation technique for producing images that have an appearance consistent with the same scan performed at a lower mAs (with fixed kVp, rotation time, and collimation). Synthetic noise is added to projection (sinogram) data, incorporating a stochastic noise model that includes energy-integrating detectors, tube-current modulation, bowtie beam filtering, and electronic system noise. Experimental methods were developed to determine the parameters required for each component of the noise model. As a validation, the outputs of the simulations were compared to measurements with cadavers in the image domain and with phantoms in both the sinogram and image domain, using an unbiased root-mean-square relative error metric to quantify agreement in noise processes. Four-alternative forced-choice (4AFC) observer studies were conducted to confirm the realistic appearance of simulated noise, and the effects of various system model components on visual noise were studied. The "just noticeable difference (JND)" in noise levels was analyzed to determine the sensitivity of observers to changes in noise level. Individual detector measurements were shown to be normally distributed (p > 0.54), justifying the use of a Gaussian random noise generator for simulations. Phantom tests showed the ability to match original and simulated noise variance in the sinogram domain to within 5.6% +/- 1.6% (standard deviation), which was then propagated into the image domain with errors less than 4.1% +/- 1.6%. Cadaver measurements indicated that image noise was matched to within 2.6% +/- 2.0%. More importantly, the 4AFC observer studies indicated that the simulated images were realistic, i.e., no detectable difference between simulated and original images (p = 0.86) was observed. JND studies indicated that observers' sensitivity to change in noise levels corresponded to a 25% difference in dose, which is far larger than the noise accuracy achieved by simulation. In summary, the dose-reduction simulation tool demonstrated excellent accuracy in providing realistic images. The methodology promises to be a useful tool for researchers and radiologists to explore dose reduction protocols in an effort to produce diagnostic images with radiation dose "as low as reasonably achievable".

Pediatric nephrolithiasis: does treatment affect renal growth?

OBJECTIVES: The long-term effects of shock wave lithotripsy on the growth of pediatric kidneys are not well defined. Likewise, no long-term data regarding renal growth after ureteroscopy or percutaneous nephrolithotomy have been published. We studied the effect of urolithiasis on renal growth in our pediatric patient population. METHODS: A total of 165 children were treated for urolithiasis at St. Louis Children's Hospital from March 1993 to December 2003. Of these 165 children, 74 were available for long-term follow-up. Four groups were evaluated: those who underwent shock wave lithotripsy, ureteroscopy, or percutaneous nephrolithotomy, and those who received no intervention. The expected renal length was calculated using Chen's nomogram, and the observed renal length was measured using renal ultrasonography. All measurements were performed by one pediatric radiologist. The expected and observed renal growth was determined by subtracting the renal length at baseline from the length at follow-up, divided by the number of months of follow-up. Statistical analysis used paired data for each treatment group, and comparisons were made on a nonparametric single-rank method. RESULTS: Of the 74 children, 39 were boys and 35 were girls, with a mean age at treatment of 9 years (range 9 months to 14 years) and a mean follow-up of 6.2 years (range 1.3 to 13.1). In all groups, the comparison between the treated side and nontreated side for expected and actual kidney size and growth was calculated as described. None of the groups had statistically significant differences in the observed or predicted renal growth rates. CONCLUSIONS: Shock wave lithotripsy, ureteroscopic stone extraction, and percutaneous nephrolithotomy do not appear to impair renal growth.