MRI and Blood-based Biomarkers Are Associated With Surgery in Children and Adults With Ileal Crohn's Disease

BACKGROUND

Despite advances in medical therapy, many children and adults with ileal Crohn's disease (CD) progress to fibrostenosis requiring surgery. We aimed to identify MRI and circulating biomarkers associated with the need for surgical management.

METHODS

This prospective, multicenter study included pediatric and adult CD cases undergoing ileal resection and CD controls receiving medical therapy. Noncontrast research MRI examinations measured bowel wall 3-dimensional magnetization transfer ratio normalized to skeletal muscle (normalized 3D MTR), modified Look-Locker inversion recovery (MOLLI) T1 relaxation, intravoxel incoherent motion (IVIM) diffusion-weighted imaging metrics, and the simplified magnetic resonance index of activity (sMaRIA). Circulating biomarkers were measured on the same day as the research MRI and included CD64, extracellular matrix protein 1 (ECM1), and granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies (Ab). Associations between MRI and circulating biomarkers and need for ileal resection were tested using univariate and multivariable LASSO regression.

RESULTS

Our study sample included 50 patients with CD undergoing ileal resection and 83 patients with CD receiving medical therapy; mean participant age was 23.9 ± 13.1 years. Disease duration and treatment exposures did not vary between the groups. Univariate biomarker associations with ileal resection included log GM-CSF Ab (odds ratio [OR], 2.87; P = .0009), normalized 3D MTR (OR, 1.05; P = .002), log MOLLI T1 (OR, 0.01; P = .02), log IVIM perfusion fraction (f; OR, 0.38; P = .04), and IVIM apparent diffusion coefficient (ADC; OR, 0.3; P = .001). The multivariable model for surgery based upon corrected Akaike information criterion included age (OR, 1.03; P = .29), BMI (OR, 0.91; P = .09), log GM-CSF Ab (OR, 3.37; P = .01), normalized 3D MTR (OR, 1.07; P = .007), sMaRIA (OR, 1.14; P = .61), luminal narrowing (OR, 10.19; P = .003), log C-reactive protein (normalized; OR, 2.75; P = .10), and hematocrit (OR, 0.90; P = .13).

CONCLUSION

After accounting for clinical and MRI measures of severity, normalized 3D MTR and GM-CSF Ab are associated with the need for surgery in ileal CD.

Association of pancreatic fat on imaging with pediatric metabolic co-morbidities

BACKGROUND

The relationship between pancreatic fat on imaging and metabolic co-morbidities has not been established in pediatrics. We sought to investigate the relationship between pancreatic fat measured by MRI and endocrine/exocrine dysfunctions along with the metabolic co-morbidities in a cohort of children.

OBJECTIVE

To investigate relationships between pancreatic fat quantified by MRI and endocrine and exocrine conditions and metabolic co-morbidities in a cohort of children. MATERIALS AND METHODS: This was a retrospective review of pediatric patients (n = 187) who had a clinically indicated MRI examination between May 2018 and February 2020. After 51 patients without useable imaging data were excluded, the remaining 136 subjects comprised the study sample. Laboratory studies were assessed if collected within 6 months of MRI and patient charts were reviewed for demographic and clinical information. MRI proton density fat fraction (PDFF) sequence had been acquired according to manufacturer's specified parameters at a slice thickness of 3 mm. Two blinded radiologists independently collected PDFF data.

RESULTS

The median age at MRI was 12.1 (IQR: 9.0-14.8) years and the majority of patients were Caucasian (79%), followed by African American and Hispanic at 12% and 11% respectively. There was a higher median pancreas fat fraction in patients with exocrine conditions (chronic pancreatitis or exocrine insufficiency) compared to those without (3.5% vs 2.2%, p = 0.03). There was also a higher median fat fraction in the head of pancreas in patients with endocrine insufficient conditions (insulin resistance, pre-diabetes, type 1 and type 2 diabetes) compared to those without endocrine insufficiency when excluding patients with active acute pancreatitis (3.5% vs 2.0%, p = 0.04). Patients with BMI > 85% had higher mean fat fraction compared to patients with BMI ≤ 85% (head: 3.8 vs 2.4%, p = 0.01; body: 3.8 vs 2.5%, p = 0.005; tail: 3.7 vs 2.7%, p = 0.049; overall pancreas fat fraction: 3.8 vs 2.6%, p = 0.002).

CONCLUSION

Pancreas fat is elevated in patients with BMI > 85% and in those with exocrine and endocrine insufficiencies.

Respiratory-Triggered Flow-Independent Noncontrast Non-ECG-Gated MRV (REACT) Versus CE-MRV for Central Venous Evaluation in Children and Young Adults: A Six-Reader Study

BACKGROUND. Contrast-enhanced MRI is commonly used to evaluate thoracic central venous patency in children and young adults. A flow-independent noncontrast non-ECG-gated 3D MRA-MR venography (MRV) technique described in 2019 as "relaxation-enhanced angiography without contrast and triggering (REACT)" may facilitate such evaluation. OBJECTIVE. The purpose of our study was to compare image quality, diagnostic confidence, and interreader agreement between respiratory-triggered REACT and 3D Dixon-based contrast-enhanced MRV (CE-MRV) for evaluating thoracic central venous patency in children and young adults. METHODS. This retrospective study included 42 consecutive children and young adults who underwent MRI of the neck and chest to evaluate central venous patency between August 2019 and January 2021 (median age, 5.2 years; IQR, 1.4-15.1 years; 22 female patients and 20 male patients). Examinations included respiratory-triggered REACT and navigator-gated CE-MRV sequences based on the institution's standard-of-care protocol. Six pediatric radiologists from four different institutions independently reviewed REACT and CE-MRV sequences; they assessed overall image quality (scale, 1-5; 5 = excellent), diagnostic confidence (scale, 1-5; 5 = extremely confident), and presence of clinically relevant artifact(s). Readers classified seven major central vessels as normal or abnormal (e.g., narrowing, thrombosis, or occlusion). Analysis used Wilcoxon signed rank and McNemar tests and Fleiss kappa coefficients. RESULTS. The distribution of overall image quality scores was higher (p = .02) for REACT than for CE-MRV for one reader (both sequences: median score, 5). Image quality scores were not significantly different between the sequences for the remaining five readers (all p > .05). Diagnostic confidence scores and frequency of clinically relevant artifact(s) were not significantly different between sequences for any reader (all p > .05). Interreader agreement for vessel classification as normal or abnormal was similar between sequences for all seven vessels (REACT: κ = 0.37-0.81; CE-MRV: κ = 0.34-0.81). Pooling readers and vessels, 65.4% of vessels were normal by both sequences; 18.7%, abnormal by both sequences; 9.8%, abnormal by REACT only; and 6.1%, abnormal by CE-MRV only. CONCLUSION. Respiratory-triggered REACT, in comparison with CE-MRV, showed no significant difference in image quality (aside from for one of six readers), diagnostic confidence, or frequency of artifact(s), with similar interreader agreement for vessel classification as normal or abnormal. CLINICAL IMPACT. High-resolution 3D MRV performed without IV contrast material can be used to assess central venous patency in children and young adults.

The Simplified MR Index of Activity Score in Pediatric Small-Bowel Crohn Disease: An Interreader Agreement and Responsiveness Study

BACKGROUND. The simplified MR index of activity (MaRIA) score is used to assess the severity of small-bowel inflammation without use of IV contrast material. OBJECTIVE. The purposes of this study were to assess interreader agreement on the use of simplified MaRIA scores for evaluation of the inflammatory activity of terminal ileal Crohn disease in children and young adults and to assess whether simplified MaRIA scores change after biologic medical therapy. METHODS. This analysis was ancillary to a previously reported primary prospective research investigation. The study included 20 children and young adults with newly diagnosed ileal Crohn disease and 15 healthy control participants who underwent research small-bowel MRI examinations between December 2018 and October 2021. The participants with Crohn disease underwent baseline MRI and MRI 6 weeks and 6 months after beginning anti-tumor necrosis factor α-treatment as well as weighted pediatric Crohn disease activity index (wPCDAI) and C-reactive protein (CRP) assessment on the day of each examination. Control participants underwent one MRI examination. Four pediatric radiologists independently assigned simplified MaRIA scores using axial and coronal T2-weighted SSFSE images. Median simplified MaRIA score among readers was computed. Interreader agreement was assessed with Fleiss kappa coefficients and intra-class correlation coefficient (ICC). Analysis included the Mann-Whitney U test, Friedman test, and Spearman rank correlation. RESULTS. Simplified MaRIA scores (across time points and study groups) had substantial interreader agreement (κ = 0.65 [95% CI, 0.56-0.74]; ICC, 0.71 [95% CI, 0.63-0.78]). Median scores were higher in participants with Crohn disease at baseline than in healthy control participants (3.5 [IQR, 2.5-4.9] vs 0.5 [IQR, 0-2.0]; p < .001). Scores decreased after medical treatment in participants with Crohn disease (p = .005). The median score was 3.5 (IQR, 2.5-4.9) at baseline, 2.3 (IQR, 1.6-3.9) at 6 weeks, and 2.0 (IQR, 0.5-2.5) at 6 months. In participants with Crohn disease, median scores had significant correlations with wPCDAI (ρ = 0.46 [95% CI, 0.18-0.64]; p < .001) and CRP level (ρ = 0.48 [95% CI, 0.27-0.65]; p < .001). CONCLUSION. Radiologists had substantial agreement in use of simplified MaRIA scores to assess intestinal inflammation in ileal Crohn disease. Scores changed over time after medical therapy. CLINICAL IMPACT. The results support the simplified MaRIA score as an objective MRI-based clinical measure of intestinal inflammation in children and young adults with Crohn disease.

Magnetic Resonance Cholangiopancreatography vs Endoscopy Retrograde Cholangiopancreatography for Detection of Anatomic Variants of the Pancreatic Duct in Children

OBJECTIVE

To compare the efficacy of magnetic resonance cholangiopancreatography (MRCP) with endoscopy retrograde cholangiopancreatography (ERCP) in children for the identification of pancreatic duct variants.

STUDY DESIGN

We identified children with a pancreatic duct variant by ERCP and separately queried our MRCP database for similar variants. Patients with a paired ERCP-MRCP were reviewed. Three radiologists blinded to the ERCP and MRCP findings were asked to independently review the MRCP studies and define the pancreatic duct anatomy. These blinded reviewers also graded the magnetic resonance imaging examination quality.

RESULTS

Seventy-four pairs of ERCP-MRCP examinations were identified. Pancreas divisum was the most frequent ductal variant encountered (73%). There was fair agreement between the radiology reviewers as to the quality of the magnetic resonance imaging studies (Fleiss Kappa agreement). Concordance of the reviewers with that of the ERCP was moderate for the exact diagnosis, moderate for the presence of pancreas divisum, and fair for agreement on the presence of any duct variant. Concordance among reviewers was moderate for the exact diagnosis, moderate for normal vs abnormal, and substantial for the presence of pancreas divisum.

CONCLUSIONS

Diagnostic limitations exist when comparing MRCP with the gold reference standard of ERCP, specifically when assessing for pancreatic duct variants in children.

Detection of urinary tract calculi on CT images reconstructed with deep learning algorithms

BACKGROUND

Deep learning Computed Tomography (CT) reconstruction (DLR) algorithms promise to improve image quality but the impact on clinical diagnostic performance remains to be demonstrated. We aimed to compare DLR to standard iterative reconstruction for detection of urolithiasis by unenhanced CT in children and young adults.

METHODS

This was an IRB approved retrospective study involving post-hoc reconstruction of clinically acquired unenhanced abdomen/pelvis CT scans. Images were reconstructed with six different manufacturer-standard DLR algorithms and reformatted in 3 planes (axial, sagittal, and coronal) at 3 mm intervals. De-identified reconstructions were loaded as independent examinations for review by 3 blinded radiologists (R1, R2, R3) tasked with identifying and measuring all stones. Results were compared to the clinical iterative reconstruction images as a reference standard. IntraClass correlation coefficients and kappa (k) statistics were used to quantify agreement.

RESULTS

CT data for 14 patients (mean age: 17.3 ± 3.4 years, 5 males and 9 females, weight class: 31-70 kg (n = 6), 71-100 kg (n = 7), > 100 kg (n = 1)) were reconstructed into 84 total exams. 7 patients had urinary tract calculi. Interobserver agreement on the presence of any urinary tract calculus was substantial to almost perfect (k = 0.71-1) for all DLR algorithms. Agreement with the reference standard on number of calculi was excellent (ICC = 0.78-0.96) and agreement on the size of the largest calculus was fair to excellent (ICC = 0.51-0.97) depending on reviewer and DLR algorithm.

CONCLUSION

Deep learning reconstruction of unenhanced CT images allows similar renal stone detectability compared to iterative reconstruction.

Artificial Intelligence Algorithm Improves Radiologist Performance in Skeletal Age Assessment: A Prospective Multicenter Randomized Controlled Trial

Background Previous studies suggest that use of artificial intelligence (AI) algorithms as diagnostic aids may improve the quality of skeletal age assessment, though these studies lack evidence from clinical practice. Purpose To compare the accuracy and interpretation time of skeletal age assessment on hand radiograph examinations with and without the use of an AI algorithm as a diagnostic aid. Materials and Methods In this prospective randomized controlled trial, the accuracy of skeletal age assessment on hand radiograph examinations was performed with (n = 792) and without (n = 739) the AI algorithm as a diagnostic aid. For examinations with the AI algorithm, the radiologist was shown the AI interpretation as part of their routine clinical work and was permitted to accept or modify it. Hand radiographs were interpreted by 93 radiologists from six centers. The primary efficacy outcome was the mean absolute difference between the skeletal age dictated into the radiologists' signed report and the average interpretation of a panel of four radiologists not using a diagnostic aid. The secondary outcome was the interpretation time. A linear mixed-effects regression model with random center- and radiologist-level effects was used to compare the two experimental groups. Results Overall mean absolute difference was lower when radiologists used the AI algorithm compared with when they did not (5.36 months vs 5.95 months; P = .04). The proportions at which the absolute difference exceeded 12 months (9.3% vs 13.0%, P = .02) and 24 months (0.5% vs 1.8%, P = .02) were lower with the AI algorithm than without it. Median radiologist interpretation time was lower with the AI algorithm than without it (102 seconds vs 142 seconds, P = .001). Conclusion Use of an artificial intelligence algorithm improved skeletal age assessment accuracy and reduced interpretation times for radiologists, although differences were observed between centers. Clinical trial registration no. NCT03530098 © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Rubin in this issue.

Hepatic Steatosis in Infancy: The Beginning of Pediatric Nonalcoholic Fatty Liver Disease?

Nonalcoholic fatty liver disease is clinically silent and the age of its onset is unknown. Fatty liver can occur as early as in utero in the context of an unfavorable maternal metabolic environment. Our objective was to determine the prevalence of hepatic steatosis in a cohort of previously healthy infants less than 3 months of age.

Methods

Retrospective study of all abdominal computed tomography (CT) scans performed from 2009 to 2019 for the investigation of trauma. Two independent reviewers applied published criteria to determine the presence of hepatic steatosis. Descriptive statistics were used. The groups with and without steatosis were compared using Wilcoxon-Mann Whitney or Fisher exact test.

Results

Of 119 CT scans available in infants younger than 3 months of age, 65 were performed in previously healthy infants for the investigation of trauma. The included population was predominantly male, non-Hispanic, with a median age of 60 days (interquartile range, 34-73 d). Depending on the criteria used, 23% or 26% of infants had evidence of fatty liver. The prevalence of maternal obesity and/or diabetes was 11% (of the 65 pregnancies) but there was no significant difference in maternal risk factors between infants with and without evidence of steatosis.

Conclusions

Findings suggest CT evidence of hepatic steatosis in up to a quarter of otherwise healthy infants ≤3 months of age. This may represent early manifestation of pediatric nonalcoholic fatty liver disease. The natural history and pathophysiology of this condition need to be studied to determine optimal detection, prevention and early intervention strategies.

Improving Image Quality and Reducing Radiation Dose for Pediatric CT by Using Deep Learning Reconstruction

Background CT deep learning reconstruction (DLR) algorithms have been developed to remove image noise. How the DLR affects image quality and radiation dose reduction has yet to be fully investigated. Purpose To investigate a DLR algorithm's dose reduction and image quality improvement for pediatric CT. Materials and Methods DLR was compared with filtered back projection (FBP), statistical-based iterative reconstruction (SBIR), and model-based iterative reconstruction (MBIR) in a retrospective study by using data from CT examinations of pediatric patients (February to December 2018). A comparison of object detectability for 15 objects (diameter, 0.5-10 mm) at four contrast difference levels (50, 150, 250, and 350 HU) was performed by using a non-prewhitening-matched mathematical observer model with eye filter (d'_NPWE), task transfer function, and noise power spectrum analysis. Object detectability was assessed by using area under the curve analysis. Three pediatric radiologists performed an observer study to assess anatomic structures with low object-to-background signal and contrast to noise in the azygos vein, right hepatic vein, common bile duct, and superior mesenteric artery. Observers rated from 1 to 10 (worst to best) for edge definition, quantum noise level, and object conspicuity. Analysis of variance and Tukey honest significant difference post hoc tests were used to analyze differences between reconstruction algorithms. Results Images from 19 patients (mean age, 11 years ± 5 [standard deviation]; 10 female patients) were evaluated. Compared with FBP, SBIR, and MBIR, DLR demonstrated improved object detectability by 51% (16.5 of 10.9), 18% (16.5 of 13.9), and 11% (16.5 of 14.8), respectively. DLR reduced image noise without noise texture effects seen with MBIR. Radiologist ratings were 7 ± 1 (DLR), 6.2 ± 1 (MBIR), 6.2 ± 1 (SBIR), and 4.6 ± 1 (FBP); two-way analysis of variance showed a difference on the basis of reconstruction type (P < .001). Radiologists consistently preferred DLR images (intraclass correlation coefficient, 0.89; 95% CI: 0.83, 0.93). DLR demonstrated 52% (1 of 2.1) greater dose reduction than SBIR. Conclusion The DLR algorithm improved image quality and dose reduction without sacrificing noise texture and spatial resolution. © RSNA, 2020 Online supplemental material is available for this article.

Automatic Detection of Inadequate Pediatric Lateral Neck Radiographs of the Airway and Soft Tissues using Deep Learning

Purpose

To develop and validate a deep learning (DL) algorithm to identify poor-quality lateral airway radiographs.

Materials and Methods

A total of 1200 lateral airway radiographs obtained in emergency department patients between January 1, 2000, and July 1, 2019, were retrospectively queried from the picture archiving and communication system. Two radiologists classified each radiograph as adequate or inadequate. Disagreements were adjudicated by a third radiologist. The radiographs were used to train and test the DL classifiers. Three technologists and three different radiologists classified the images in the test dataset, and their performance was compared with that of the DL classifiers.

Results

The training set had 961 radiographs and the test set had 239. The best DL classifier (ResNet-50) achieved sensitivity, specificity, and area under the receiver operating characteristic curve of 0.90 (95% confidence interval [CI]: 0.86, 0.94), 0.82 (95% CI: 0.76, 0.90), and 0.86 (95% CI: 0.81, 0.91), respectively. Interrater agreement for technologists was fair (Fleiss κ, 0.36 [95% CI: 0.29, 0.43]), while that for radiologists was moderate (Fleiss κ, 0.59 [95% CI: 0.52, 0.66]). Cohen κ value comparing the consensus rating of ResNet-50 iterations from fivefold cross-validation, consensus technologists' rating, and consensus radiologists' rating to the ground truth were 0.76 (95% CI: 0.63, 0.89), 0.49 (95% CI: 0.37, 0.61), and 0.66 (95% CI: 0.54, 0.78), respectively.

Conclusion

The development and validation of DL classifiers to distinguish between adequate and inadequate lateral airway radiographs is reported. The classifiers performed significantly better than a group of technologists and as well as the radiologists.© RSNA, 2020.

Inter-radiologist agreement using Society of Abdominal Radiology-American Gastroenterological Association (SAR-AGA) consensus nomenclature for reporting CT and MR enterography in children and young adults with small bowel Crohn disease

PURPOSE

To assess inter-radiologist agreement using the Society of Abdominal Radiology-American Gastroenterological Association (SAR-AGA) consensus recommendations for reporting CT/MR enterography exams in pediatric and young adult small bowel Crohn disease (CD).

METHODS

Institutional review board approval was obtained for this HIPAA-compliant retrospective investigation; the requirement for informed consent was waived. 25 CT and 25 MR enterography exams performed in children and young adults (age range: 6-23 years) between January 2015 and April 2017 with a distribution of ileal CD severity (phenotype) were identified: normal or chronic CD without active inflammation (40%), active inflammatory CD (20%), stricturing CD (20%), and penetrating CD (20%). Five fellowship-trained pediatric radiologists, blinded to one another, documented key imaging findings and standardized impressions based on SAR-AGA consensus recommendations. Inter-radiologist agreement was evaluated using Fleiss' multi-rater kappa statistic (κ) with 95% confidence intervals (CI).

RESULTS

Inter-radiologist agreement was moderate for all key imaging findings except presence of ulcerations (κ 0.37 [95% CI 0.28-0.46]) and sacculations (κ 0.31 [95% CI 0.23-0.40]). Agreement for standardized impressions was substantial for stricturing disease (κ 0.79 [95% CI 0.70-0.87]) and moderate for presence of inflammation (κ 0.49 [95% CI 0.44-0.56]) and penetrating disease (κ 0.58 [95% CI 0.49-0.67]). No significant difference in agreement was found between CT and MRI.

CONCLUSIONS

Agreement among five pediatric radiologists was moderate to substantial for SAR-AGA standardized impressions and fair to moderate for key imaging findings of pediatric and young adult CD.

Normal pancreatic parenchymal thickness by CT in healthy children

BACKGROUND

Chronic pancreatitis is increasingly recognized in the pediatric population. Atrophy is an important, but qualitative, finding of chronic pancreatitis. To transition to a quantitative measure that can specifically define atrophy requires knowledge of normal pancreatic parenchymal bulk in children.

OBJECTIVE

The purpose of this study was to define normal pancreatic thickness (linear measurements) at multiple anatomic locations in the pancreas of healthy children.

MATERIALS AND METHODS

This was an Institutional Review Board-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study. Three reviewers measured the thickness of the pancreas at four locations (head, neck, body, tail) on computed tomography (CT) examinations performed with intravenous contrast in children without a history of pancreatic disease. Measurements were made on 140 examinations, evenly distributed among 7 age groups (3-16.99 years) with 10 males and 10 females in each group. Agreement and bias between reviewers were assessed by intra-class correlation coefficients (ICC) and Bland-Altman analyses. Correlation with age, height and weight were assessed with Spearman's rho (ρ).

RESULTS

The mean (for 3 readers) thicknesses of the head, neck, body and tail were 1.3-2 cm, 0.7-1 cm, 0.9-1.6 cm and 1-1.6 cm, respectively, depending on patient age. Measurement agreement between reviewers was fair to good (ICC: 0.52-0.7). Bias between reviewers ranged from 0 to 3 mm. Pancreatic thickness was weakly to moderately correlated with age (ρ=0.39-0.52), height (ρ=0.44-0.61) and weight (ρ=0.51-0.64).

CONCLUSION

We have defined normal ranges for thickness of the pancreas at four locations, and have shown that these measurements depend on patient age and size. These data may be useful to more objectively define pancreatic atrophy in children with suspected pancreatic disease.

Hoverboards: spectrum of injury and association with an uncommon fracture

BACKGROUND

Self-balancing electric scooters, commonly known as hoverboards, are a new and popular consumer item with recognized fall hazards. The spectrum of injuries associated with hoverboard use has not been studied.

OBJECTIVE

The purpose of this study is to determine the spectrum of radiologically apparent injuries associated with hoverboard use.

MATERIALS AND METHODS

We retrospectively reviewed all imaging studies interpreted at our institution for hoverboard-related injuries during an 8-month period. We recorded patient demographics and injury characteristics.

RESULTS

Thirty-two of the 47 pediatric patients imaged for hoverboard-related injury had radiologically detectable injuries, all fractures. Fifty percent of these 32 patients were female and 50% were male, with a mean age of 12.4 years. There were 42 fractures total, all involving the appendicular skeleton, with 74% in the upper extremities and 26% in the lower extremities. Thirty-eight percent of the fractures involved the physis. A distinct injury pattern was seen in three patients who sustained open distal phalanx juxta-epiphyseal fractures.

CONCLUSION

Most of the fractures sustained during hoverboard use are commonly seen in everyday pediatric radiology practice, with an overall pattern paralleling that reported in association with skateboard use. However an otherwise uncommon fracture, the distal phalanx juxta-epiphyseal fracture, was identified in association with hoverboard use, and this finding has important treatment implications including need for irrigation and debridement, antibiotic therapy, and potential surgical fixation.

Pediatric elbow fractures: a new angle on an old topic

BACKGROUND

The three most common elbow fractures classically reported in pediatric orthopedic literature are supracondylar (50-70%), lateral condylar (17-34%), and medial epicondylar fractures (10%), with fractures of the proximal radius (including but not limited to fractures of the radial neck) being relatively uncommon (5-10%). Our experience at a large children's hospital suggests a different distribution.

OBJECTIVE

Our goals were (1) to ascertain the frequency of different elbow fracture types in a large pediatric population, and (2) to determine which fracture types were occult on initial radiographs but detected on follow-up.

MATERIALS AND METHODS

Review of medical records identified 462 children, median age 6 years and interquartile range for age of 4-8 years (range 0.8-18 years), who were diagnosed with elbow fractures at our institution over a 10-month period. Initial and follow-up radiographs were reviewed in blinded fashion independently by two experienced pediatric musculoskeletal radiologists to identify fracture types on initial and follow-up radiographs.

RESULTS

The most common fractures included supracondylar (n = 258, 56%), radial neck (n = 80, 17%), and lateral condylar (n = 69, 15%). Additional fractures were seen on follow-up exams in 32 children. Of these, 25 had a different fracture type than was identified on initial radiographs. The most common follow-up fractures were olecranon (n = 23, 72%), coronoid process (n = 4, 13%) and supracondylar (n = 3, 9%). Olecranon fractures were significantly more common on follow-up radiographs than they were on initial radiographs (n = 33, 7%; P < .0001). Twenty-six children had more than one fracture type on the initial radiograph. The most common fracture combinations were radial neck with olecranon (n = 9) and supracondylar with lateral condylar (n = 9).

CONCLUSION

Supracondylar fractures are the most frequent elbow fracture seen initially, followed by radial neck, lateral condylar, and olecranon fractures in a distribution different from what has been historically described. The relatively high frequency of olecranon fractures detected on follow-up speaks to their potentially occult nature. Careful attention to these areas is warranted in children with initially normal radiographs.

Normal spinous process metaphyseal-equivalent lucency simulating infant abuse fractures

We report a normal radiographic finding that may be mistaken for child abuse trauma in the posterior thoracolumbar spinous processes of young infants after the first week of life. A lucency paralleling the posterior margin of the ossified spinous process is equivalent to the metaphyseal lucent bands seen normally after about a week of the child's age at the ends of long tubular bones. A similar lucency is seen just under the growth plate of vertebral bodies at that early age, giving the bone-in-bone appearance. Our index case was imaged at 3 weeks and then at 5 weeks of age, with no evidence of periosteal reaction or endosteal callus on that follow-up study, confirming the lack of fractures.

MRI of radiographically occult ischial apophyseal avulsions

BACKGROUND

Acute avulsions of unossified ischial apophyses in children may go undetected on radiography. Therapy includes rest and rehabilitation; however, substantial displacement may require surgery.

OBJECTIVE

Our purpose is to illustrate the utility of MRI in the detection of these radiographically occult injuries in skeletally immature children.

MATERIALS AND METHODS

This retrospective study of more than 5 years included children with ischial avulsions who were evaluated with both radiography and MRI within 3 weeks of acute injury. Initially, radiographs were reviewed to identify those children with unossified ischial apophyses. Subsequently, their MRI examinations were assessed for physeal disruption, bone/soft tissue edema, periosteal/perichondrial elevation and disruption. Initial and follow-up radiographs (if available) were reviewed. Patient age, symptoms and offending activity were determined from clinical records.

RESULTS

Five children met inclusion criteria. All initial radiographs were normal. MRI showed: edema (n = 5), periosteal elevation (n = 4), periosteal/perichondrial disruption (n = 4), >5.5 mm displacement (n = 0). Follow-up radiographs in two children (2 and 2.5 months from MRI) showed osseous ischial irregularity. The apophyses remained unossified.

CONCLUSIONS

Acute unossified ischial apophyseal avulsions in children may be radiographically undetected. In the setting of correlative clinical symptoms, MRI can be used to identify these injuries and to help direct appropriate therapy.

CT evaluation of extensor tendon entrapment as a complication of a distal radial fracture in a child

Extensor indicis proprius (EIP) entrapment is a rare complication of a distal radial fracture. We report an 11-year-old with limited flexion of her index finger 1 year after a distal radial fracture. The utility of cross-sectional imaging in the diagnosis and preoperative planning of this complication is presented.

MRI of acquired posterior urethral diverticulum following surgery for anorectal malformations

BACKGROUND

Posterior urethral diverticulum (PUD) is one of the most common postoperative complications associated with anorectal malformation (ARM) correction.

OBJECTIVE

To describe our MRI protocol for evaluating acquired PUD following ARM surgery, and associated imaging findings.

MATERIALS AND METHODS

Two radiologists retrospectively reviewed 61 pelvic MRI examinations performed for postoperative ARM for PUD identification and characteristics. Associated clinical, operative and cystoscopy reports were also reviewed and compared to MRI.

RESULTS

An abnormal retrourethral focus suspicious for PUD was identified at MRI in 13 patients. Ten of these patients underwent subsequent surgery or cystoscopy, and PUD was confirmed in five. All of the confirmed PUD cases appeared as cystic lesions that were at least 1 cm in diameter in two imaging planes. Four of the false-positive cases were punctate retrourethral foci that were visible only on a single MRI plane. One patient had a seminal vesical cyst mimicking a PUD.

CONCLUSION

Pelvic MRI can be a useful tool in the postoperative assessment of suspected PUD associated with ARM. Radiologists should have a high clinical suspicion for a postoperative PUD when a cystic lesion posterior to the bladder/posterior urethra is encountered on two imaging planes in these patients.

Imaging of American football injuries in children

It is estimated that 3.2 million children ages 6 to 14 years participated in organized youth football in the United States in 2007. Approximately 240,000 children play football in the nation's largest youth football organization, with tackle divisions starting at age 5 years. The number of children playing unsupervised football is much higher, and the overall number of children participating in American football is increasing. Sports are the leading cause of injury-related emergency room visits for teenagers, and football is a leading precipitating athletic activity for these visits. Football is also the most hazardous organized sports in the United States. Though most pediatric football-related injuries are minor, such as abrasions, sprains, and strains of the extremities, football accounts for more major and catastrophic injuries than any other sport. Given football's popularity with children in the United States, combined with the high rate of injury associated with participation in this activity, radiologists should be familiar with the imaging features and injury patterns seen in this patient population.

Tailgut cyst in a child

Tailgut cyst, or retrorectal cystic hamartoma, is a rare congenital lesion found in the presacral space. The lesion has been infrequently reported in the literature. We report the MRI findings of a tailgut cyst in a 2-year-old girl who presented with a sacral dimple and skin discoloration.

"Missing" sternal ossification center: potential mimicker of disease in young children

PURPOSE

To evaluate the frequency of "missing" sternal ossification center (asynchronous non-ossification) in young children.

MATERIALS AND METHODS

Lateral chest radiographs obtained in 229 children (mean age, 3.7 years) were retrospectively evaluated for sternal ossification. Four superior sternal segments were considered normal if they were ossified to a similar degree. A segment was considered asynchronous if decreased ossification, as compared with the remaining sternal segments, was demonstrated or if ossification was absent. Asynchronous ossification of inferior sternal segment 5 was recorded separately. Logistic regression analysis was applied to determine if there was a statistically significant relationship (P <.05) between age or sex and pattern of sternal ossification (normal vs asynchronous).

RESULTS

Of the 916 superior four sternal segments (four segments in each of 229 patients) evaluated, 32 (3.5%) showed asynchronously decreased or absent ossification. Locations of these 32 segments follow: segment 1, two (0.2%) instances; segment 2, 14 (1.5%) instances; segment 3, two (0.2%) instances; and segment 4, 14 (1.5%) instances. Inferior segment 5 was not ossified in 73 (31.9%) patients. There was a statistically significant relationship between decreased age and increased likelihood of occurrence of asynchronous ossification of one of the sternal ossification centers 1-4 (P >.003) and of occurrence of asynchronous ossification at sternal segment 2 (P <.018).

CONCLUSION

Missing sternal ossification centers occur most commonly at segments 2 and 4. Such asynchronous non-ossifications become less common in older children.

Proximal Femoral Focal Deficiency(PFFD): More Than An Abnormal Hip

As the name implies, proximal femoral focal deficiency (PFFD) is a failure in development of the proximal femur and acetabulum of varying degrees. This article reviews the classification schemes with illustrated examples. Clinical findings, associated anomalies, imaging, and treatment are discussed. Patients are classified by radiographs, often changing classes as the patientÕs skeleton matures. Magnetic resonance imaging (MRI) can aid in earlier and more accurate classification. The classification scheme exists to predict future function and the role of surgical intervention.

Minimizing radiation dose for pediatric body applications of single-detector helical CT: strategies at a large Children's Hospital

Adjustments of the standard helical CT protocols for adults can result in reduced radiation dose when imaging children. It is the radiologist's responsibility to critically evaluate the CT techniques used at their institution. Adjustments to CT protocols should be made to choose the appropriate mA and pitch when imaging children.