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Thoracic back pain is a common site for inflammatory, neoplastic, metabolic, infectious, and degenerative conditions, and may be associated with significant disability and morbidity. Uncomplicated acute thoracic back pain and/or radiculopathy does not typically warrant imaging. Imaging may be considered in those patients who have persistent pain despite 6 weeks of conservative treatment. Early imaging may also be warranted in patients presenting with "red flag" history or symptoms, including those with a known or suspected history of cancer, infection, immunosuppression, or trauma; in myelopathic patients; or in those with a history of prior thoracic spine fusion. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation. [ABSTRACT FROM AUTHOR]

Soft tissue vascular anomalies may be composed of arterial, venous, and/or lymphatic elements, and diagnosed prenatally or later in childhood or adulthood. They are divided into categories of vascular malformations and vascular tumors. Vascular malformations are further divided into low-flow and fast-flow lesions. A low-flow lesion is most common, with a prevalence of 70%. Vascular tumors may behave in a benign, locally aggressive, borderline, or malignant manner. Infantile hemangioma is a vascular tumor that presents in the neonatal period and then regresses. The presence or multiple skin lesions in an infant can signal underlying visceral vascular anomalies, and complex anomalies may be associated with overgrowth syndromes. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation. [ABSTRACT FROM AUTHOR]

Urinary tract infection (UTI) is a frequent infection in childhood. The diagnosis is usually made by history and physical examination and confirmed by urine analysis. Cystitis is infection or inflammation confined to the bladder, whereas pyelonephritis is infection or inflammation of kidneys. Pyelonephritis can cause renal scarring, which is the most severe long-term sequela of UTI and can lead to accelerated nephrosclerosis, leading to hypertension and chronic renal failure. The role of imaging is to guide treatment by identifying patients who are at high risk to develop recurrent UTIs or renal scarring. This document provides initial imaging guidelines for children presenting with first febrile UTI with appropriate response to medical management, atypical or recurrent febrile UTI, and follow-up imaging for children with established vesicoureteral reflux. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation. [ABSTRACT FROM AUTHOR]

Brown fat can present challenges in patients with cancer who undergo 18F-FDG PET scans. Uptake of 18F-FDG by brown fat can obscure or appear similar to active oncologic lesions, causing clinical challenges in PET interpretation. Small, retrospective studies have reported environmental and pharmacologic interventions for suppressing brown fat uptake on PET; however, there is no clear consensus on best practices. We sought to characterize practice patterns for strategies to mitigate brown fat uptake of 18F-FDG during PET scanning. Methods: A survey was developed and distributed via e-mail LISTSERV to members of the Children's Oncology Group diagnostic imaging committee, the Society for Nuclear Medicine and Molecular Imaging pediatric imaging council, and the Society of Chiefs of Radiology at Children's Hospitals between April 2022 and February 2023. Responses were stored anonymously in REDCap, aggregated, and summarized using descriptive statistics. Results: Fifty-five complete responses were submitted: 51 (93%) faculty and fellow-level physicians, 2 (4%) technologists, and 2 (4%) respondents not reporting their rank. There were 43 unique institutions represented, including 5 (12%) outside the United States. Thirty-eight of 41 (93%) institutions that responded on environmental interventions reported using warm blankets in the infusion and scanning rooms. Less than a third (n = 13, 30%) of institutions reported use of a pharmacologic intervention, with propranolol (n = 5, 38%) being most common, followed by fentanyl (n = 4, 31%), diazepam (n = 2, 15%), and diazepam plus propranolol (n = 2, 15%). Selection criteria for pharmacologic intervention varied, with the most common criterion being brown fat uptake on a prior scan (n = 6, 45%). Conclusion: Clinical practices to mitigate brown fat uptake on pediatric 18F-FDG PET vary widely. Simple environmental interventions including warm blankets or increasing the temperature of the injection and scanning rooms were not universally reported. Less than a third of institutions use pharmacologic agents for brown fat mitigation. [ABSTRACT FROM AUTHOR]

Context: Most individuals with Turner syndrome (TS) require estrogen for pubertal induction. Current estrogen dosing guidelines are based on expert consensus opinion. Objective: Evaluate whether current international guidelines for estrogen dosing during pubertal induction of individuals with TS result in normal uterine growth. We hypothesized that uterine size in individuals with TS who reached adult estrogen dosing is smaller than in mature females without TS. Methods: Cross-sectional study of patients with TS at the Cincinnati Center for Pediatric and Adult Turner Syndrome Care. Twenty-nine individuals (age 15-26 years) with primary ovarian insufficiency who reached adult estrogen dosing (100 µg of transdermal or 2 mg of oral 17β-estradiol) were included. Comparison of uterine measurements with a published sample of 292 age-appropriate (age 15-20 years) controls without TS. Uterine length, volume, and fundal–cervical ratio (FCR) were measured. Clinical information (karyotype, Tanner staging for breast development, laboratory data) was extracted from an existing institutional patient registry. Results: There was no evidence of compromise of the uterine size/configuration in the TS cohort compared with the controls; in fact, uterine length, mean 7.7 cm (±1.3) vs 7.2 cm (±1.0) (P = .03), and volume, mean 60.6 cm3 (±26.6) vs 50.5 cm3 (±20.5) (P = .02), were both larger in individuals with TS. Conclusion: Current international guidelines for hormone replacement using 17β-estradiol in individuals with TS appear adequate to allow for normal uterine growth by the end of pubertal induction. [ABSTRACT FROM AUTHOR]

Background: Advanced positron emission tomography (PET) image reconstruction methods promise to allow optimized PET/CT protocols with improved image quality, decreased administered activity and/or acquisition times. Objective: To evaluate the impact of reducing counts (simulating reduced acquisition time) in block sequential regularized expectation maximization (BSREM) reconstructed pediatric whole-body 18F-fluorodeoxyglucose (FDG) PET images, and to compare BSERM with ordered-subset expectation maximization (OSEM) reconstructed reduced-count images. Materials and methods: Twenty children (16 male) underwent clinical whole-body 18F-FDG PET/CT examinations using a 25-cm axial field-of-view (FOV) digital PET/CT system at 90 s per bed (s/bed) with BSREM reconstruction (β=700). Reduced count simulations with varied BSREM β levels were generated from list-mode data: 60 s/bed, β=800; 50 s/bed, β=900; 40 s/bed, β=1000; and 30 s/bed, β=1300. In addition, a single OSEM reconstruction was created at 60 s/bed based on prior literature. Qualitative (Likert scores) and quantitative (standardized uptake value [SUV]) analyses were performed to evaluate image quality and quantitation across simulated reconstructions. Results: The mean patient age was 9.0 ± 5.5 (SD) years, mean weight was 38.5 ± 24.5 kg, and mean administered 18F-FDG activity was 4.5 ± 0.7 (SD) MBq/kg. Between BSREM reconstructions, no qualitative measure showed a significant difference versus the 90 s/bed β=700 standard (all P>0.05). SUVmax values for lesions were significantly lower from 90 s/bed, β=700 only at a simulated acquisition time of 30 s/bed, β=1300 (P=0.001). In a side-by-side comparison of BSREM versus OSEM reconstructions, 40 s/bed, β=1000 images were generally preferred over 60 s/bed TOF OSEM images. Conclusion: In children who undergo whole-body 18F-FDG PET/CT on a 25-cm FOV digital PET/CT scanner, reductions in acquisition time or, by corollary, administered radiopharmaceutical activity of >50% from a clinical standard of 90 s/bed may be possible while maintaining diagnostic quality when a BSREM reconstruction algorithm is used. [ABSTRACT FROM AUTHOR]

Background: Acute pancreatitis (AP) increases the risk of diabetes mellitus (DM). Our aim was to identify clinical, laboratory and imaging predictors of preDM/DM in youth post index AP., Methods: This was a prospective cohort study of patients ≤21 years-old with an index admission for AP and follow up at 3 and/or 12 months. Clinical laboratory values, imaging findings, admission course, and plasma chemokine and cytokine measures collected at index admission were tested for association with preDM/DM development. A multivariable regression model was used to predict preDM/DM., Results: Among 187 enrolled participants, 137 (73 %) and 144 (77 %) underwent DM screening at 3 and 12 months respectively, and 137 (73 %) had imaging available. PreDM/DM occurred in 22/137 (16 %; preDM n = 21, DM n = 1) at 3 months and 23/144 (16 %; preDM n = 18, DM n = 5) participants at 12 months. Univariate associations with preDM/DM at 12 months included: severe AP (SAP) (52 % preDM/DM vs. 17 % no DM; p = 0.0008), median [IQR] IL-6 (910 pg/ml [618-3438] vs. 196 pg/ml [71-480], p < 0.05) and CRP (4.16 mg/L [1.67-10.7] vs. 1.55 mg/L [0.4-3.68], p = 0.1) at time of AP attack. The optimal multivariable model to predict preDM/DM included with clinical variables was severe acute pancreatitis (SAP), c reactive protein (CRP), interleukin-6 (IL-6), and age [AUC = 0.80; (0.70, 0.88)]. Including imaging markers, the ideal model included SAP, CRP, IL-6, subcutaneous fat area, age and presence of autoimmune disease with an AUC [0.82 (0.71, 0.90)]., Conclusions: Development of preDM/DM following an index AP episode can be predicted by baseline AP severity, baseline CRP, IL-6 levels, and subcutaneous fat area., Competing Interests: Conflicts of interest G Ginzburg has no declarations of interest. Y Zhang has no declarations of interest. NK Abu Ata has no declarations of interest. PR Farrell has no declarations of interest. V Garlapally has no declarations of interest. N Kotha has no declarations of interest. T Thompson has no declarations of interest. DS Vitale has no declarations of interest. AT Trout has consulted for GE Healthcare; has Research support from GE Healthcare, Siemens Healthineers, and Perspectum Inc. No support was received for the current work. M Abu-El-Haija has no declarations of interest., (Copyright © 2024. Published by Elsevier Ltd.)

Introduction: Original research in radiology often involves handling large datasets, data manipulation, statistical tests, and coding. Recent studies show that large language models (LLMs) can solve bioinformatics tasks, suggesting their potential in radiology research. This study evaluates an LLM's ability to provide statistical and deep learning solutions and code for radiology research., Materials and Methods: We used web-based chat interfaces available for ChatGPT-4o, ChatGPT-3.5, and Google Gemini. EXPERIMENT 1: BIOSTATISTICS AND DATA VISUALIZATION: We assessed each LLMs' ability to suggest biostatistical tests and generate R code for the same using a Cancer Imaging Archive dataset. Prompts were based on statistical analyses from a peer-reviewed manuscript. The generated code was tested in R Studio for correctness, runtime errors and the ability to generate the requested visualization. EXPERIMENT 2: DEEP LEARNING: We used the RSNA-STR Pneumonia Detection Challenge dataset to evaluate ChatGPT-4o and Gemini's ability to generate Python code for transformer-based image classification models (Vision Transformer ViT-B/16). The generated code was tested in a Jupiter Notebook for functionality and run time errors., Results: Out of the 8 statistical questions posed, correct statistical answers were suggested for 7 (ChatGPT-4o), 6 (ChatGPT-3.5), and 5 (Gemini) scenarios. The R code output by ChatGPT-4o had fewer runtime errors (6 out of the 7 total codes provided) compared to ChatGPT-3.5 (5/7) and Gemini (5/7). Both ChatGPT4o and Gemini were able to generate visualization requested with a few run time errors. Iteratively copying runtime errors from the code generated by ChatGPT4o into the chat helped resolve them. Gemini initially hallucinated during code generation but was able to provide accurate code on restarting the experiment. ChatGPT4-o and Gemini successfully generated initial Python code for deep learning tasks. Errors encountered during implementation were resolved through iterations using the chat interface, demonstrating LLM utility in providing baseline code for further code refinement and resolving run time errors., Conclusion: LLMs can assist in coding tasks for radiology research, providing initial code for data visualization, statistical tests, and deep learning models helping researchers with foundational biostatistical knowledge. While LLM can offer a useful starting point, they require users to refine and validate the code and caution is necessary due to potential errors, the risk of hallucinations and data privacy regulations., Summary Statement: LLMs can help with coding and statistical problems in radiology research. This can help primary authors trouble shoot coding needed in radiology research., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Background: When applying lung-nodule computer-aided detection (CAD) systems for pediatric CT, performance may be degraded on low-dose scans due to increased image noise. Objective: To conduct an intraindividual comparison of the performance for lung nodule detection of two CAD systems trained using adult data between low-dose and standard-dose pediatric chest CT scans. Methods: This retrospective study included 73 patients (32 female, 41 male; mean age, 14.7 years; age range, 4-20 years) who underwent both clinical standard-dose and investigational low-dose chest CT examinations within the same encounter from November 30, 2018 to August 31, 2020 as part of an earlier prospective study. Fellowship-trained pediatric radiologists annotated lung nodules to serve as the reference standard. Both CT scans were processed using two publicly available lung-nodule CAD systems previously trained using adult data: FlyerScan and Medical Open Network for Artificial Intelligence (MONAI). The systems' sensitivities for nodules measuring 3-30 mm (n=247) were calculated when operating at a fixed frequency of two false-positives per scan. Results: FlyerScan exhibited detection sensitivities of 76.9% (190/247; 95% CI: 73.3-80.8%) on standard-dose scans and 66.8% (165/247; 95% CI: 62.6-71.5) on low-dose scans. MONAI exhibited detection sensitivities of 67.6% (167/247, 95% CI: 61.5-72.1) on standard-dose scans and 62.3% (154/247, 95% CI: 56.1-66.5%) on low-dose scans. The number of detected nodules for standard-dose versus low-dose scans for 3-mm nodules was 33 versus 24 (FlyerScan) and 16 versus 13 (MONAI), 4-mm nodules was 46 versus 42 (FlyerScan) and 39 versus 30 (MONAI), 5-mm nodules was 38 versus 33 (FlyerScan) and 32 versus 31 (MONAI), and 6-mm nodules was 27 versus 20 (FlyerScan) and 24 versus 24 (MONAI). For nodules measuring ≥7 mm, detection did not show a consistent pattern between standard-dose and low-dose scans for either system. Conclusions: Two lung-nodule CAD systems demonstrated decreased sensitivity on low-dose versus standard-dose pediatric CT scans performed in the same patients. The reduced detection at low dose was overall more pronounced for nodules measuring less than 5 mm. Clinical Impact: Caution is needed when using low-dose CT protocols in combination with CAD systems to help detect small lung nodules in pediatric patients.

By exploiting different tissues' characteristic T 1 relaxation times, T 1 -weighted images help distinguish normal and abnormal tissues, aiding assessment of diffuse and local pathologies. However, such images do not provide quantitative T 1 values. Advances in abdominal MRI techniques have enabled measurement of abdominal organs' T 1 relaxation times, which can be used to create color-coded quantitative maps. T 1 mapping is sensitive to tissue microenvironments including inflammation and fibrosis and has received substantial interest for noninvasive imaging of abdominal organ pathology. In particular, quantitative mapping provides a powerful tool for evaluation of diffuse disease by making apparent changes in T 1 occurring across organs that may otherwise be difficult to identify. Quantitative measurement also facilitates sensitive monitoring of longitudinal T 1 changes. Increased T 1 in liver helps to predict parenchymal fibro-inflammation, in pancreas is associated with reduced exocrine function from chronic or autoimmune pancreatitis, and in kidney is associated with impaired renal function and aids diagnosis of chronic kidney disease. In this review, we describe the acquisition, postprocessing, and analysis of T 1 maps in the abdomen and explore applications in liver, spleen, pancreas, and kidney. We highlight practical aspects of implementation and standardization, technical pitfalls and confounding factors, and areas of likely greatest clinical impact.

Background: Quantitative parametric mapping is an increasingly important tool for noninvasive assessment of chronic liver disease. Conventional parametric mapping techniques require multiple breath-held acquisitions and provide limited anatomic coverage., Purpose: To investigate a multi-inversion spin and gradient echo (MI-SAGE) technique for simultaneous estimation of T 1 , T 2 , and T 2 * of the liver., Study Type: Prospective., Subjects: Sixteen research participants, both adult and pediatric (age 17.5 ± 4.6 years, eight male), with and without known liver disease (seven asymptomatic healthy controls, two fibrotic liver disease, five steatotic liver disease, and two fibrotic and steatotic liver disease)., Field Strength/sequence: 1.5 T, single breath-hold and respiratory triggered MI-SAGE, breath-hold modified Look-Locker inversion recovery (MOLLI, T 1 mapping), breath-hold gradient and spin echo (GRASE, T 2 mapping), and multiple gradient echo (mGRE, T 2 * mapping) sequences., Assessment: Agreement between hepatic T 1 , T 2 , and T 2 * estimated using MI-SAGE and conventional parametric mapping sequences was evaluated. Repeatability and reproducibility of MI-SAGE were evaluated using a same-session acquisition and second-session acquisition., Statistical Tests: Bland-Altman analysis with bias assessment and limits of agreement (LOA) and intraclass correlation coefficients (ICC)., Results: Hepatic T 1 , T 2 , and T 2 * estimates obtained using the MI-SAGE technique had mean biases of 72 (LOA: -22 to 166) msec, -3 (LOA: -10 to 5) msec, and 2 (LOA: -5 to 8) msec (single breath-hold) and 36 (LOA: -43 to 120) msec, -3 (LOA: -17 to 11) msec, and 4 (LOA: -3 to 11) msec (respiratory triggered), respectively, in comparison to conventional acquisitions using MOLLI, GRASE, and mGRE. All MI-SAGE estimates had strong repeatability and reproducibility (ICC > 0.72)., Data Conclusion: Hepatic T 1 , T 2 , and T 2 * estimates obtained using an MI-SAGE technique were comparable to conventional methods, although there was a 12%/6% for breath-hold/respiratory triggered underestimation of T 1 values compared to MOLLI. Both respiratory triggered and breath-hold MI-SAGE parameter maps demonstrated strong repeatability and reproducibility., Level of Evidence: 1 TECHNICAL EFFICACY: Stage 2., (© 2024 The Author(s). Journal of Magnetic Resonance Imaging published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

BACKGROUND. Deep learning abdominal organ segmentation algorithms have shown excellent results in adults; validation in children is sparse. OBJECTIVE. The purpose of this article is to develop and validate deep learning models for liver, spleen, and pancreas segmentation on pediatric CT examinations. METHODS. This retrospective study developed and validated deep learning models for liver, spleen, and pancreas segmentation using 1731 CT examinations (1504 training, 221 testing), derived from three internal institutional pediatric (age ≤ 18 years) datasets ( n = 483) and three public datasets comprising pediatric and adult examinations with various pathologies ( n = 1248). Three deep learning model architectures (SegResNet, DynUNet, and SwinUNETR) from the Medical Open Network for Artificial Intelligence (MONAI) framework underwent training using native training (NT), relying solely on institutional datasets, and transfer learning (TL), incorporating pretraining on public datasets. For comparison, TotalSegmentator, a publicly available segmentation model, was applied to test data without further training. Segmentation performance was evaluated using mean Dice similarity coefficient (DSC), with manual segmentations as reference. RESULTS. For internal pediatric data, the DSC for TotalSegmentator, NT models, and TL models for normal liver was 0.953, 0.964-0.965, and 0.965-0.966, respectively; for normal spleen, 0.914, 0.942-0.945, and 0.937-0.945; for normal pancreas, 0.733, 0.774-0.785, and 0.775-0.786; and for pancreas with pancreatitis, 0.703, 0.590-0.640, and 0.667-0.711. For public pediatric data, the DSC for TotalSegmentator, NT models, and TL models for liver was 0.952, 0.871-0.908, and 0.941-0.946, respectively; for spleen, 0.905, 0.771-0.827, and 0.897-0.926; and for pancreas, 0.700, 0.577-0.648, and 0.693-0.736. For public primarily adult data, the DSC for TotalSegmentator, NT models, and TL models for liver was 0.991, 0.633-0.750, and 0.926-0.952, respectively; for spleen, 0.983, 0.569-0.604, and 0.923-0.947; and for pancreas, 0.909, 0.148-0.241, and 0.699-0.775. The DynUNet TL model was selected as the best-performing NT or TL model considering DSC values across organs and test datasets and was made available as an open-source MONAI bundle (https://github.com/cchmc-dll/pediatric&#95;abdominal&#95;segmentation&#95;bundle.git). CONCLUSION. TL models trained on heterogeneous public datasets and fine-tuned using institutional pediatric data outperformed internal NT models and Total-Segmentator across internal and external pediatric test data. Segmentation performance was better in liver and spleen than in pancreas. CLINICAL IMPACT. The selected model may be used for various volumetry applications in pediatric imaging.

BACKGROUND. Liver fibrosis is an important clinical endpoint of the progression of autoimmune liver disease (AILD); its monitoring would benefit from noninvasive imaging tools. OBJECTIVE. The purpose of this study was to assess the relationship between MR elastography (MRE) liver stiffness measurements and histologic liver fibrosis, as well as to evaluate the performance of MRE and biochemical-based clinical markers for stratifying histologic liver fibrosis severity, in children and young adults with AILD. METHODS. This retrospective study used an existing institutional registry of children and young adults diagnosed with AILD (primary sclerosing cholangitis [PSC], autoimmune sclerosing cholangitis [ASC], or autoimmune hepatitis [AIH]). The registry was searched to identify patients who underwent both a research abdominal 1.5-T MRI examination that included liver MRE (performed for registry enrollment) and a clinically indicated liver biopsy within 6 months of that examination. MRE used a 2D gradient-recalled echo sequence. One analyst measured mean liver shear stiffness (in kilopascals) for each examination. Laboratory markers of liver fibrosis (aspartate aminotransferase-to-platelet ratio index [APRI] and fibrosis-4 [FIB-4] score) were recorded. For investigational purposes, one pathologist, blinded to clinical and MRI data, determined histologic Metavir liver fibrosis stage. The Spearman rank order correlation coefficient was calculated between MRE liver stiffness and Metavir liver fibrosis stage. ROC analysis was used to evaluate diagnostic performance for identifying advanced fibrosis (i.e., differentiating Metavir F0-F1 from F2-F4 fibrosis), and sensitivity and specificity were calculated using the Youden index. RESULTS. The study included 46 patients (median age, 16.6 years [IQR, 13.7-17.8 years]; 20 female patients, 26 male patients); 12 had PSC, 10 had ASC, and 24 had AIH. Median MRE liver stiffness was 2.9 kPa (IQR, 2.2-4.0 kPa). MRE liver stiffness and Metavir fibrosis stage showed strong positive correlation (ρ = 0.68). For identifying advanced liver fibrosis, MRE liver stiffness had an AUC of 0.81, with sensitivity of 65.4% and specificity of 90.0%; APRI had an AUC of 0.72, with sensitivity of 64.0% and specificity of 80.0%; and FIB-4 score had an AUC of 0.71, with sensitivity of 60.0% and specificity of 85.0%. CONCLUSION. MRE liver stiffness measurements were associated with histologic liver fibrosis severity. CLINICAL IMPACT. The findings support a role for MRE in noninvasive monitoring of liver stiffness, a surrogate for fibrosis, in children and young adults with AILD. TRIAL REGISTRATION. ClinicalTrials.gov NCT03175471.

BACKGROUND. Pancreatic duct (PD) or common bile duct (CBD) dilatation can indicate ductal pathology, but limited data describe normal pediatric duct measurements on routine 2D MRI sequences. OBJECTIVE. The purpose of this study was to characterize the visibility and diameter of the PD and CBD on 2D MR images in children without pancreaticobiliary disease. METHODS. This retrospective study included patients who underwent abdominal MRI using a rapid protocol (composed of noncontrast axial and coronal 2D SSFSE sequences) to assess for suspected appendicitis or ovarian torsion in the emergency department setting between January 23, 2023, and September 13, 2023, and excluded patients with a pancreatic or hepatobiliary abnormality on MRI or laboratory assessment. Four pediatric radiologists independently reviewed examinations. Reviewers recorded PD visibility in each of four segments (i.e., head, neck, body, and tail) and CBD visibility, and reviewers measured PD diameter in each segment and maximal CBD diameter. Duct measurements by age were characterized by linear regression analyses. RESULTS. The study included 177 patients (112 female patients, 65 male patients; mean age, 12.3 ± 3.4 [SD] years [age range, 5.1-17.7 years]). The observers reported PD visibility in the head in 35.6-94.9% of patients, neck in 18.6-72.3%, body in 22.6-89.8%, and tail in 7.3-26.0% and reported PD visibility in all four segments in 6.2-22.6% of patients. Maximum PD diameter in any segment, as a mean across observers, was 1.8 mm (range across observers, 0.7-3.5 mm). The expected maximal PD diameter in any segment, in terms of the 5th and 95th percentile values of observers' mean measurements, was 1.4-2.3 mm; the prediction interval's upper limit increased from age 5 to age 17 from 2.1 to 2.5 mm. All observers reported CBD visibility in all patients. The mean CBD diameter across observers was 3.1 mm (range across observers, 2.9-3.4 mm). The expected CBD diameter, in terms of the 5th and 95th percentile values of observers' mean measurements, was 2.3-4.9 mm; the prediction interval's upper limit increased from age 5 to age 17 from 3.9 to 5.0 mm. CONCLUSION. We report expected upper limits for PD and CBD measurements on 2D MR images in children without evidence of pancreaticobiliary disease. CLINICAL IMPACT. These findings may aid radiologists' identification of pancreaticobiliary duct abnormalities on routine abdominal MRI examinations.

Brown fat can present challenges in patients with cancer who undergo 18 F-FDG PET scans. Uptake of 18 F-FDG by brown fat can obscure or appear similar to active oncologic lesions, causing clinical challenges in PET interpretation. Small, retrospective studies have reported environmental and pharmacologic interventions for suppressing brown fat uptake on PET; however, there is no clear consensus on best practices. We sought to characterize practice patterns for strategies to mitigate brown fat uptake of 18 F-FDG during PET scanning. Methods: A survey was developed and distributed via e-mail LISTSERV to members of the Children's Oncology Group diagnostic imaging committee, the Society for Nuclear Medicine and Molecular Imaging pediatric imaging council, and the Society of Chiefs of Radiology at Children's Hospitals between April 2022 and February 2023. Responses were stored anonymously in REDCap, aggregated, and summarized using descriptive statistics. Results: Fifty-five complete responses were submitted: 51 (93%) faculty and fellow-level physicians, 2 (4%) technologists, and 2 (4%) respondents not reporting their rank. There were 43 unique institutions represented, including 5 (12%) outside the United States. Thirty-eight of 41 (93%) institutions that responded on environmental interventions reported using warm blankets in the infusion and scanning rooms. Less than a third ( n = 13, 30%) of institutions reported use of a pharmacologic intervention, with propranolol ( n = 5, 38%) being most common, followed by fentanyl ( n = 4, 31%), diazepam ( n = 2, 15%), and diazepam plus propranolol ( n = 2, 15%). Selection criteria for pharmacologic intervention varied, with the most common criterion being brown fat uptake on a prior scan ( n = 6, 45%). Conclusion: Clinical practices to mitigate brown fat uptake on pediatric 18 F-FDG PET vary widely. Simple environmental interventions including warm blankets or increasing the temperature of the injection and scanning rooms were not universally reported. Less than a third of institutions use pharmacologic agents for brown fat mitigation., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)

MRI is increasingly used as an alternate to CT for the evaluation of suspected appendicitis in pediatric patients presenting to the emergency department (ED) with abdominal pain, when further imaging is needed after an initial ultrasound examination. The available literature shows a similar diagnostic performance of MRI and CT in this setting. At the authors' institution, to evaluate for appendicitis in children in the ED, MRI is performed using a rapid three-sequence free-breathing protocol without IV contrast media. Implementation of an MRI program for appendicitis in children involves multiple steps, including determination of imaging resource availability, collaboration with other services to develop imaging pathways, widespread educational efforts, and regular quality review. Such programs can face numerous practice-specific challenges, such as those involving scanner capacity, costs, and buy-in of impacted groups. Nonetheless, through careful consideration of these factors, MRI can be used to positively impact the care of children presenting to the ED with suspected appendicitis. This Clinical Perspective aims to provide guidance on the development of a program for appendicitis MRI in children, drawing on one institution's experience while highlighting the advantages of MRI and practical strategies for overcoming potential barriers.