Katherine N. Epstein

Implementing a rapid MRI program requires buy-in and collaboration from all stakeholders and can lead to fast, accurate diagnosis of common and uncommon pediatric pathologic conditions in the emergent setting.

Background: Ovarian-Adnexal Reporting & Data System Ultrasound (O-RADS US) is a validated scoring system in adult women with adnexal lesions to help assess the risk of potential malignancy. Limited data exists for children in whom malignancy is rare. Objective: To evaluate inter-radiologist agreement and diagnostic performance when using the O-RADS US in pediatric patients with ovarian lesions. Materials and methods: Retrospective IRB-approved study included pelvic ultrasounds (US) from 2015 to 2020 in pediatric patients (3 cm in premenarchal patients and >5 cm in menarchal patients were included. Three pediatric radiologists reviewed each US and recorded imaging characteristics and O-RADS classification. Diagnostic performance was assessed, and agreement among radiologists was calculated. Results: In total, 160 pelvic US exams were included in 160 patients, with a mean patient age of 12.1 years (SD=4.9). Most lesions were classified as O-RADS 2 (almost certainly benign), and fewer cases as O-RADS 4 (intermediate risk) or O-RADS 5 (high risk). Inter-radiologist agreement for O-RADS category was moderate ( κ =0.42). Diagnostic performance of US O-RADS demonstrated high sensitivity and NPV (100% for all three reviewers). Specificities were 74-82%, and PPV was low at 5-7% for distinguishing malignant/borderline lesions from benign lesions. Conclusions: Application of the O-RADS US system in pediatric patients may be challenging due to the low overall malignancy rate. Nevertheless, an O-RADS 2 classification provides meaningful reassurance, reflecting minimal malignancy risk in children. Larger studies are needed to determine the clinical utility of O-RADS US and whether pediatric-specific modifications are required. Graphical

Background Some children with inflammatory bowel disease (IBD) have hepatobiliary and/or pancreatic manifestations of the disease. The frequency of related imaging abnormalities at IBD diagnosis is unknown. Objective To identify and quantify hepatobiliary and pancreatic findings on baseline magnetic resonance enterography (MRE) examinations in children with newly diagnosed IBD. Materials and methods Children n=86) with Crohn disease; 22% (n=24) with ulcerative colitis; 1% (n=1) with IBD-unspecified. The mean age at diagnosis was 13.7 years (range, 5.3-17.9 years); 61% (n=43) were male. Subjective intrahepatic biliary dilation by reviewer consensus was present in 11% (n=12). Extrahepatic biliary dilation was present in 6% (n=7). Pancreatic duct dilation was present in 2% (n=2). Low pancreas:spleen T1 SIR (n=16). Pancreatic volume was 95th percentile in 13% (n=14). Conclusions Imaging findings potentially associated with autoimmune-related hepatobiliary or pancreatic disease are present in 2-14% on baseline MR enterography examinations in children with newly diagnosed inflammatory bowel disease. While infrequent, radiologists should be attentive to these findings of multisystem disease.

Background: There is a paucity of data comparing contrast-enhanced ultrasound (CEUS) to MR enterography in children and young adults with Crohn’s disease. Objective: To measure correlations across CEUS quantitative metrics in children and young adults with Crohn’s disease, and to evaluate if these metrics are associated with MRI features of disease activity. Materials and methods: Patients 0.8 (Pr=0.40; P=0.046), visual analog scale assessment of overall inflammation (r=0.43; P=0.032), and postcontrast enhancement ratio (r=0.47; P=0.018); there were no other significant correlations between CEUS metrics and MRI measures of inflammation. Conclusion: CEUS quantitative measurements are highly variable across patients with Crohn’s disease, with multiple metrics being highly correlated with one another. CEUS rise time correlates with MRI features of disease activity. Graphical

Objectives Implementation of diffusion-weighted imaging (DWI) for abdominal imaging in children has challenges due to motion artifacts exacerbated by long acquisition times. We aimed to compare acquisition time and image quality between conventional DWI and multi-band (MB) DWI of the liver in children and young adults. Methods Clinical MRI exams from May 2023 to January 2024 were reviewed, including four DWI sequences: respiratory-triggered (RTr, clinical standard), free-breathing (FB), MB-DWI with shift factor 1 (MBsf1), and MB-DWI with shift factor 2 (MBsf2). Acquisition times were recorded, and signal intensity and apparent signal-to-noise ratio (aSNR) were calculated for the liver and spleen. Six blinded pediatric radiologists independently assessed image quality, artifacts, and lesion visualization on a 5-point Likert scale and identified their preferred sequence. Statistical comparisons were made using Kruskal-Wallis and ANOVA tests. Results Median acquisition times were significantly reduced with MB-DWI (43 s for MBsf1/MBsf2) compared to FB (84 s) and RTr (240 s). Image quality and artifact scores were highest for RTr and FB sequences (p < 0.0001). Mean image quality scores were 3.7 (RTr, FB), 3.4 (MBsf1), and 3.5 (MBsf2), while artifact scores followed a similar trend (higher score = fewer artifacts). Lesion visualization scores were comparable across sequences (p = 0.11), and reviewers expressed no preference in 47% of cases. Apparent diffusion coefficient (ADC) values were consistent across all sequences (p > 0.05). Conclusion MB-DWI significantly reduces acquisition time while maintaining acceptable image quality and lesion visualization, making it a valuable option for pediatric abdominal MRI.

Background Ovarian enlargement is one of several findings of pathology, including ovarian torsion. With increasing use of MRI for acute abdominal pain in children, data for normal ovary size and appearance are needed. Objective To provide preliminary data on normal sizes of ovaries on MRI in pediatric patients. Materials and methods This retrospective IRB-approved study included girls (5 to 17 years of age) with MRI examinations performed for indications not related to the ovaries from 2018 to 2022. For each MRI, coronal T2-weighted single shot fast spin echo and axial T2-weighted fat-saturated images were independently reviewed by three pediatric radiologists who recorded ovary visualization and ovarian linear measurements (3 planes). Ovarian volumes were calculated from linear measurements. Agreement among observers was calculated using kappa statistics and intraclass correlation coefficients. Results A total of 181 MRIs were reviewed. The left ovary was visualized in 166–176 (92–97%) cases (R1–R3) and the right ovary was visualized in 165–174 (91–96%) cases with excellent agreement among reviewers (left: K = 0.89 [0.84–0.94], right: K = 0.85 [0.79–0.91]). Interrater class coefficient (ICC) for largest single dimension of the ovary was left: 0.83 (CI 0.79–0.87) and right: 0.85 (CI 0.81–0.89). There were significant moderate to strong correlations between ovarian volume and age (left: 0.67 [0.58–0.75], right: 0.66 [0.57–0.74]). Conclusion The ovaries can be adequately visualized and measured on MRI with excellent inter-reader agreement. This study serves as the foundation for developing normative values for ovarian volumes by age on MRI. Graphical Abstract

Background Transabdominal ultrasound (US) is first-line imaging to evaluate ovaries in girls presenting to the emergency department (ED) with suspected ovarian torsion. Ovaries may be difficult to visualize sonographically; therefore, prompt diagnosis using US alone can be challenging. Rapid MRI as first-line imaging may help streamline patient throughput, especially with increasing MRI availability in the ED. Objective To assess feasibility of rapid MRI for diagnosis of ovarian torsion. Materials and Methods A retrospective, single-center IRB approved study of MRI performed in female pediatric patients presenting with abdominopelvic pain from August 2022 to January 2023. Imaging occurred according to one of three clinical pathways (US-first approach vs MRI-first approach vs US + MRI-second-line approach). A rapid three-sequence free-breathing MRI protocol was utilized. Frequency of ovarian torsion and secondary diagnoses was recorded. Length of MR scan time, time from ED arrival to time of diagnosis, and whether patient had US prior to MR exam were obtained. A historical cohort of patients with US only performed for assessment of ovarian torsion were evaluated for length of the US examination and time from ED arrival to time of diagnosis. Intervals were compared using the uncorrected Fisher’s least significant difference and Turkey’s multiple comparison tests. Results A total of 140 MRI exams (mean age 14.6 years) and 248 historical US exams (mean age 13.5 years) were included. Of the patients with MRI, 41 (29%) patients were imaged with US + MRI and 99 (71%) imaged with MRI only; 4% (6/140) MR exams were suspicious for ovarian torsion, with one true positive case (1/6 TP) and 5 false positive cases (5/6 FP); 26.4% (37/140) of exams had secondary diagnoses. Median MRI scan time was 11.4 min (4.4) vs median historical US scan time was 24.1 min (19.7) (P<0.001). Median time from arrival in ED to MRI read was 242 (140). Median time from arrival in ED to US only read was 268 min (148). This was not a statistically significant difference when compared to the MRI only cohort. Conclusion First-line MRI imaging for evaluation of ovarian torsion is a rapid and feasible imaging modality for female patients in the emergent setting. Graphical Abstract

Soft tissue and osseous musculoskeletal infections are common but can be difficult to diagnose clinically. Signs, symptoms, and physical examination findings may be nonspecific, and laboratory values can be in- conclusive. The extent of disease may also be underestimated on physical examination. Soft tissue infections most commonly occur secondary to direct inoculation from broken skin and less frequently due to the seed- ing of the soft tissues from hematogenous spread, while osseous infections are more commonly due to he- matogenous seeding. Infections may also be iatrogenic, following surgery or other procedural interventions. High-resolution ultrasound is an extremely useful imaging modality in the evaluation of musculoskeletal soft tissue and joint infections, and can occasionally be used to evaluate osseous infections as well. Ultrasound can aid in the early diagnosis of musculoskeletal infections, allowing for prompt treatment, decreased risk of complications, and treatment optimization. Ultrasound is sensitive and specific in evaluating soft tissue edema and hyperemia; soft tissue abscesses; joint, bursal and tendon sheath effusions/synovitis; and subperi- osteal abscesses. This article describes the typical high-resolution grayscale as well as color and power Dop- pler ultrasound imaging findings of soft tissue infections including cellulitis, fasciitis, necrotizing deep soft tissue infection, pyomyositis, soft tissue abscess, infectious bursitis, and infectious tenosynovitis. Ultrasound findings of septic arthritis as well as osteomyelitis, such as subperiosteal spread of infection (subperiosteal abscess). are also reviewed. In addition, the use of ultrasound to guide fluid and tissue sampling is discussed.

Pediatric radiology studies can be some of the most anxiety-inducing imaging examinations encountered in practice. This can be in part due to the wide range of normal anatomic appearances inherent to the pediatric population that create potential interpretive pitfalls for radiologists. The pediatric head is no exception; for instance, the inherent greater water content within the neonatal brain compared to older patients could easily be mistaken for cerebral edema, and anatomic variant calvarial sutures can be mistaken for skull fractures. This article reviews potential pitfalls emergency radiologists may encounter in practice when interpreting pediatric head CTs, including trauma, extra-axial fluid collections, intra-axial hemorrhage, and ventriculoperitoneal shunt complications.