Introduction to the COG Diagnostic Imaging Committee/SPR Oncology Committee White Papers: Rationale and methods.

Pediatric cancer is a rare disease. Because of this, many sites do not have experience providing imaging for specific tumor types. The Children's Oncology Group Diagnostic Imaging Committee and the Society for Pediatric Radiology Oncology Committee are comprised of radiologists with expertise in pediatric cancer imaging. Recently, this group endeavored to create a series of 23 White Papers designed to provide evidence-based imaging recommendations and minimum achievable imaging protocols. The purpose of this manuscript is to describe the methods employed in authoring the White Paper series.

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

Cardiac tumors in children are rare and the majority are benign. The most common cardiac tumor in children is rhabdomyoma, usually associated with tuberous sclerosis complex. Other benign cardiac masses include fibromas, myxomas, hemangiomas, and teratomas. Primary malignant cardiac tumors are exceedingly rare, with the most common pathology being soft tissue sarcomas. This paper provides consensus-based imaging recommendations for the evaluation of patients with cardiac tumors at diagnosis and follow-up, including during and after therapy.

Optimizing Imaging of Pediatric Liver Lesions: Guidelines from the Pediatric LI-RADS Working Group.

A differential diagnosis based on a patient's age, clinical presentation, and serum α-fetoprotein level will help guide the initial imaging workup in children with a liver lesion. Children vary significantly in size, the ability to stay still, and the ability to breath hold for imaging examinations. Choosing and tailoring imaging techniques and protocols for each indication and age group is important for optimal care with minimal invasiveness. The need for sedation or anesthesia can be obviated by using techniques like feed and bundle, distraction, contrast-enhanced US, and motion-insensitive sequences for MRI. US is often the first imaging modality used in children with a suspected abdominal mass. Once a hepatic lesion is confirmed, multiphasic contrast-enhanced MRI is recommended for most lesions as the next imaging modality allowing full characterization of the lesion and assessment of the liver parenchyma. Contrast-enhanced CT can also be performed for assessment of pediatric focal liver lesions, especially in patients who have a contraindication to MRI. Contrast-enhanced US has shown promise to decrease the need for MRI or CT in some lesions such as hemangioma and focal nodular hyperplasia. Children with a history of malignancy can develop multiple types of hepatic lesions at various stages, including infections during an immunocompromised state, manifesting as focal liver lesions. Based on available limited data in the literature and the collective experiences of the Liver Imaging and Reporting Data System Pediatric Working Group, the authors provide guidelines for the imaging workup of pediatric focal liver lesions with an indication- and age-based approach and discuss the selection and performance of various imaging techniques and modalities. ©RSNA, 2022 See the invited commentary by Chojniak and Boaventura in this issue.

Cancer Therapy-related Hepatic Injury in Children: Imaging Review from the Pediatric LI-RADS Working Group.

The liver is the primary organ for the metabolism of many chemotherapeutic agents. Treatment-induced liver injury is common in children undergoing cancer therapy. Hepatic injury occurs due to various mechanisms, including biochemical cytotoxicity, hepatic vascular injury, radiation-induced cytotoxicity, and direct hepatic injury through minimally invasive and invasive surgical treatments. Treatment-induced liver injury can be seen contemporaneous with therapy and months to years after therapy is complete. Patients can develop a combination of hepatic injuries manifesting during and after treatment. Acute toxic effects of cancer therapy in children include hepatitis, steatosis, steatohepatitis, cholestasis, hemosiderosis, and vascular injury. Longer-term effects of cancer therapy include hepatic fibrosis, chronic liver failure, and development of focal liver lesions. Quantitative imaging techniques can provide useful metrics for disease diagnosis and monitoring, especially in treatment-related diffuse liver injury such as hepatic steatosis and steatohepatitis, hepatic iron deposition, and hepatic fibrosis. Focal liver lesions, including those developing as a result of treatment-related vascular injury such as focal nodular hyperplasia-like lesions and hepatic perfusion anomalies, as well as hepatic infections occurring as a consequence of immune suppression, can be anxiety provoking and confused with recurrent malignancy or hepatic metastases, although there often are imaging features that help elucidate the correct diagnosis. Radiologic evaluation, in conjunction with clinical and biochemical screening, is integral to diagnosing and monitoring hepatic complications of cancer therapy in pediatric patients during therapy and after therapy completion for long-term surveillance. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material See the invited commentary by Ferraciolli and Gee in this issue.

Contrast-enhanced voiding urosonography (CEVUS) as a safe alternate means of assessing vesicoureteral reflux in pediatric kidney transplant patients.

BACKGROUND: Although voiding cystourethrogram (VCUG) is currently the gold standard in VUR evaluation, there is ionizing radiation exposure. Contrast-enhanced voiding urosonography (CEVUS) uses ultrasound contrast agents to visualize the urinary tract and has been reported to be safe and effective in VUR evaluation in children. CEVUS application has yet to be specifically described in VUR evaluation in the pediatric kidney transplant population. The purpose of this study was to report the use of CEVUS and VCUG in evaluating and managing VUR in pediatric renal transplant patients. METHODS: Retrospective review was conducted for pediatric kidney transplant patients (18 years and younger) who underwent VCUG or CEVUS to assess for transplant VUR from July 2019 through June 2021. Demographic information, reason for VUR evaluation, fluoroscopy time, and postimaging complications were evaluated. Costs of imaging modalities were also considered. RESULTS: Eight patients were evaluated for transplant VUR during the study period. Of the 3 patients who underwent VCUG, all 3 had VUR (median grade 3). Median fluoroscopy time was 18 s and dose-area product was 18.7 uGy*m2 . Of the 5 patients who underwent CEVUS, 4 had VUR (median grade 4). There were no complications for either modality. Based on clinical and radiographic findings, patients were recommended no intervention, behavioral modification, or ureteral reimplantation. The total cost of CEVUS was $800 less than that of VCUG. CONCLUSION: CEVUS can provide an alternate means of safely evaluating VUR in kidney transplant patients with similar outcomes, potentially lower costs, and no exposure to ionizing radiation.

Ultrasound Evaluation of Pediatric Slow-Flow Vascular Malformations: Practical Diagnostic Reporting to Guide Interventional Management.

OBJECTIVE. This article reviews the ultrasound characteristics of pediatric slow-flow vascular malformations and underscores findings that significantly impact diagnosis and treatment. Key imaging features are discussed including lesion size, malformation location, morphology, and mimics. CONCLUSION. Ultrasound findings affect the management of slow-flow vascular malformations and should be emphasized in lesion diagnosis. Superficial, focal lesions with well-defined margins are ideal for ultrasound evaluation.

Transjugular intrahepatic portosystemic shunt creation may be associated with hyperplastic hepatic nodular lesions in the long term: an analysis of 18 pediatric and young adult patients.

BACKGROUND: Retrospective studies have demonstrated the efficacy and safety of pediatric and adolescent transjugular intrahepatic portosystemic shunt (TIPS), but long-term outcomes warrant further investigation. OBJECTIVE: To report on the development of hyperplastic hepatic nodular lesion development in children and young adults (<21 years) with TIPS patency >3 years. MATERIALS AND METHODS: Eighteen children and young adults, including 10 (55.6%) females and 8 (44.4%) males, underwent TIPS creation with >3 years' patency and follow-up evaluation at a tertiary children's hospital. The mean age at the time of TIPS creation was 12.5±5.1 years (range: 1.5-20.0 years). The mean model for end-stage liver disease (MELD) at the time of TIPS creation was 8.1±1.6 (range: 6-11). Indications for TIPS creation included acute variceal bleeding (8/18, 44.4%), primary (1/18, 5.6%) or secondary (7/18, 38.9%) prevention of varices, portal vein thrombosis (1/18, 5.6%), and splenic sequestration (1/18, 5.6%). Technical successes, intra-procedural parameters, hemodynamic and clinical successes, TIPS patencies, adverse events, imaging evaluations, and follow-ups were recorded. RESULTS: All (100%) TIPS placements were successful; however, a direct intrahepatic portosystemic shunt was created in one (5.6%) patient. Mean reduction of the portosystemic shunt gradient was 9.1±3.3 mmHg (range: 4-16 mmHg). Seventeen (94.4%) patients demonstrated clinical success with resolution of their initial clinical indication for TIPS placement. The 3-year TIPS primary, primary-assisted, and secondary patencies were 83.3% (15/18), 94.4% (17/18), and 100% (18/18), respectively. Two (11.1%) patients developed mild, medically controlled hepatic encephalopathy. One (5.6%) patient developed hepatopulmonary syndrome. Nine (50%) patients developed single or multiple hepatic nodules at a mean imaging surveillance time after TIPS of 4.4±3.0 years (range: 1.5-10.2 years). Six (33.3%) patients developed nodules >1 cm with imaging features most consistent with focal nodular hyperplasia or focal nodular hyperplasia-like nodules. The mean follow-up duration was 5.7±2.9 years (range: 3.0-13.1 years). CONCLUSION: Long-term (>3 years) portosystemic shunting via TIPS is associated with the development of hepatic nodular lesions in children. Consequently, children with TIPS may need gray-scale assessment of hepatic parenchyma as part of routine ultrasound exams and extended imaging surveillance until more is understood regarding the natural history of induced nodularity.

Applications of Pediatric Body CT Angiography: What Radiologists Need to Know.

OBJECTIVE. Pediatric CT angiography (CTA) can be useful for assessing numerous congenital and acquired disorders. This article discusses common pediatric applications of thoracoabdominal CTA, including for congenital pulmonary airway malformation, sequestration, vascular rings, aortic coarctation, pulmonary embolism, nontraumatic hemorrhage, abdominal transplant evaluation, and several vascular disorders, and highlights key clinical and imaging features. CONCLUSION. With appropriate use, CTA can play a fundamental role in diagnostic and preprocedural assessment in a variety of pediatric conditions.

Optimization of Pediatric Body CT Angiography: What Radiologists Need to Know.

OBJECTIVE. Pediatric CT angiography (CTA) presents unique challenges compared with adult CTA. Because of the ionizing radiation exposure, CTA should be used judiciously in children. The pearls offered here are observations gleaned from the authors' experience in the use of pediatric CTA. We also present some potential follies to be avoided. CONCLUSION. Understanding the underlying principles and paying meticulous attention to detail can substantially optimize dose and improve the diagnostic quality of pediatric CTA.

Imaging of stroke: Part 1, Perfusion CT--overview of imaging technique, interpretation pearls, and common pitfalls.

OBJECTIVE: Perfusion CT is being increasingly used as a diagnostic tool for the evaluation of acute ischemic stroke. It can be performed rapidly and aids in the detection of salvageable tissue (penumbra) from the unsalvageable core infarct. The purpose of this article is to provide an overview of the imaging technique, interpretation pearls, and common pitfalls encountered in perfusion CT of the brain. CONCLUSION: Perfusion CT has proven to be a valuable tool in the diagnosis of acute ischemic stroke. The knowledge provided by these cases will allow the reader not only to confidently identify the presence of acute ischemic stroke, but also to recognize the common pitfalls and limitations of perfusion CT in this setting.

Pediatric radiologic manifestations of COVID-19.

PURPOSE: While full description of pediatric COVID-19 manifestations is evolving, children appear to present less frequently, and often display a less severe disease phenotype. There is correspondingly less data regarding pediatric radiologic findings. To describe the imaging findings of pediatric COVID-19, we evaluated the radiologic imaging of the initial patient cohort identified at our institution. METHODS: In this IRB approved study, all patients at our institution aged 0-21 with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) based on PCR or immunoglobulin testing were identified. Imaging was reviewed by the co-authors and presence of abnormalities determined by consensus. Pre-existing comorbidities and alternative diagnoses were recorded. Rates of each finding were calculated. Findings were compared to published data following review of the available literature. RESULTS: Out of 130 Covid-19 positive patients, 24 patients underwent imaging, including 21 chest radiographs and 4 chest CT scans. Chest x-rays were normal in 33%. Patchy or streaky opacities were the most common radiographic abnormality, each seen in 38% of patients. CT findings included ill-defined or geographic ground glass opacities, dense opacities, septal thickening and crazy paving, and small pleural effusions. Results are similar to those reported in adults. Multiple COVID-19 positive children presented for symptoms due to an additional acute illness, including appendicitis and urinary infection. CONCLUSIONS: Radiologic findings of COVID-19 in pediatric patients range from normal to severe ARDS type appearance. During this ongoing pandemic, these radiographic signs can be useful for the evaluation of disease status and guiding care, particularly in those with comorbidities. PRECIS: Radiologic findings of COVID-19 in pediatric patients are similar to those seen in adults, and may range from normal to severe ARDS type appearance.

Utility of 18F-FDG PET/CT in Infantile Myofibromatosis.

Infantile myofibromatosis, a rare, nonmalignant disease seen almost exclusively in the pediatric population, can involve skin, muscle, soft tissues, bone, or viscera in either solitary or multicentric pattern. Although nonmalignant, visceral involvement in infantile myofibromatosis is a key prognostic indicator, which is associated with mortality in 75% of patients. Those with pulmonary involvement have a particularly poor outcome. This case illustrates the diagnostic utility of F-FDG PET/CT in defining disease extent in this unusual entity and compares it to other commonly used imaging modalities.

Perforated jejunitis in a child with acute lymphoblastic leukemia treated with pegaspargase.

Survival rates of children with acute lymphoblastic leukemia have improved since the incorporation of asparaginase in the treatment protocol, but the medication has potential serious complications, including vascular thrombosis. Here, we describe the case of a 13-year-old boy with pre-T-cell acute lymphoblastic leukemia whose treatment course was complicated by perforated jejunitis requiring resection of a portion of his small bowel. Pathologic assessment showed transmural ischemia, mesenteric venous and arterial thrombi, and scattered cytomegalovirus inclusion bodies. Pediatric mesenteric ischemia is rare, and its consideration in patients treated with asparaginase is discussed.

Advances in lung adenocarcinoma classification: a summary of the new international multidisciplinary classification system (IASLC/ATS/ERS).

Due to advances in the understanding of lung adenocarcinoma since the advent of its 2004 World Health System classification, an international multidisciplinary panel [sponsored by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS)] has recently updated the classification system for lung adenocarcinoma, the most common histologic type of lung cancer. Here, we summarize and highlight the new criteria and terminology, certain aspects of its clinical relevance and its potential treatment impact, and future avenues of research related to the new system.

Effect of testosterone administration on liver fat in older men with mobility limitation: results from a randomized controlled trial.

BACKGROUND: Androgen receptor (AR) knockout male mice display hepatic steatosis, suggesting that AR signaling may regulate hepatic fat. However, the effects of testosterone replacement on hepatic fat in men are unknown. The aim of this study was to determine the effects of testosterone administration on hepatic fat in older men with mobility limitation and low testosterone levels who were participating in a randomized trial (the Testosterone in Older Men trial). METHODS: Two hundred and nine men with mobility limitation and low total or free testosterone were randomized in the parent trial to either placebo or 10-g testosterone gel daily for 6 months. Hepatic fat was determined by magnetic resonance imaging in 73 men (36 in placebo and 37 in testosterone group) using the volumetric method. Insulin sensitivity (homeostatic model assessment-insulin resistance) was derived from fasting glucose and insulin. RESULTS: Baseline characteristics were similar between the two groups, including liver volumes (1583 ± 363 in the testosterone group vs 1522 ± 271 mL in the placebo group, p = .42). Testosterone concentrations increased from 250 ± 72 to 632 ± 363 ng/dL in testosterone group but did not change in placebo group. Changes in liver volume during intervention did not differ significantly between groups (p = .5) and were not related to on-treatment testosterone concentrations. The change in homeostatic model assessment-insulin resistance also did not differ significantly between groups and was not related to either baseline or change in liver fat. CONCLUSION: Testosterone administration in older men with mobility limitation and low testosterone levels was not associated with a reduction in hepatic fat. Larger trials are needed to determine whether testosterone replacement improves liver fat in men with nonalcoholic hepatic steatosis.