Dual-source computed tomography protocols for the pediatric chest - scan optimization techniques.

The gold standard for pediatric chest imaging remains the CT scan. An ideal pediatric chest CT has the lowest radiation dose with the least motion degradation possible in a diagnostic scan. Because of the known inherent risks and costs of anesthesia, non-sedate options are preferred. Dual-source CTs are currently the fastest, lowest-dose CT scanners available, utilizing an ultra-high-pitch mode resulting in sub-second CTs. The dual-energy technique, available on dual-source CT scanners, gathers additional information such as pulmonary blood volume and includes relative contrast enhancement and metallic artifact reduction, features that are not available in high-pitch flash mode. In this article we discuss the benefits and tradeoffs of dual-source CT scan modes and tips on image optimization.

Contrast-enhanced ultrasound for musculoskeletal indications in children.

The increasing use of contrast-enhanced ultrasound (CEUS) has opened exciting new frontiers for musculoskeletal applications in adults and children. The most common musculoskeletal-related CEUS applications in adults are for detecting inflammatory joint diseases, imaging skeletal muscles and tendon perfusion, imaging postoperative viability of osseous and osseocutaneous tissue flaps, and evaluating the malignant potential of soft-tissue masses. Pediatric musculoskeletal-related CEUS has been applied for imaging juvenile idiopathic arthritis and Legg-Calvé-Perthes disease and for evaluating femoral head perfusion following surgical hip reduction in children with developmental hip dysplasia. CEUS can improve visualization of the capillary network in superficial and deep tissues and also in states of slow- or low-volume blood flow. In addition, measurements of blood flow imaging parameters performed by quantitative CEUS are valuable when monitoring the outcome of treatment interventions. In this review article we present current experience regarding a wide range of CEUS applications in musculoskeletal conditions in adults and children, with emphasis on the latter, and discuss imaging techniques and CEUS findings in musculoskeletal applications.

After-hours radiology coverage in children's hospitals: a multi-center survey.

BACKGROUND: Although the provision of pediatric emergency and trauma radiology has become increasingly prevalent in North America over the last few years, many hospitals differ in their models of providing after-hours coverage. OBJECTIVE: To describe the scope of after-hours radiology services provided in children's hospitals in North America, and the means by which different radiology departments deliver this coverage. MATERIALS AND METHODS: The Society for Pediatric Radiology Emergency and Trauma Imaging Committee developed a survey that we electronically distributed to a single representative from each of the 79 hospitals represented in the Society of Chiefs of Radiology at Children's Hospitals (SCORCH). RESULTS: Completed questionnaires were submitted between Aug. 2, 2017, and Sept. 29, 2017, by 44/79 (56%) SCORCH representatives. Contemporaneous after-hours interpretation of radiographs (81%), ultrasounds (81%), body CT (79%) and neurologic CT (75%) with preliminary or final reports was common. Coverage was accomplished most commonly by a combination of evening and overnight shifts 17/44 (39%). Eleven of 44 (25%) hospitals used a model in which radiologists rotate working blocks of overnight service followed by blocks off service. Only 2/44 (5%) hospitals exclusively provided pager coverage after hours. Attending pediatric radiologists were assigned to the majority of after-hours shifts 110/175 (63%), but radiology trainees provided interpretations independently for varying periods of time at 19/44 (43%) surveyed hospitals. Incentives to work after hours included the option to work remotely, as well as additional income, time off, and academic time. CONCLUSION: The model for delivering after-hours pediatric radiology coverage varies. Most hospitals, however, provide contemporaneous interpretations of radiographs, US, body CT and neurologic CT. Most institutions use evening shifts to extend coverage later, with many providing subsequent overnight coverage. Although most shifts are staffed by attending pediatric radiologists, radiology trainees commonly interpret studies independently for varying durations of time after hours.

Gaucher disease status and treatment assessment: pilot study using magnetic resonance spectroscopy bone marrow fat fractions in pediatric patients.

OBJECTIVE: To assess magnetic resonance spectroscopy (MRS) bone marrow fat fractions' ability to discern between untreated Gaucher disease patients and healthy controls based on assessment of bone marrow infiltration and evaluate response to enzyme replacement therapy (ERT) on serial imaging. METHODS: This retrospective case-controlled study compared conventional MRI and bone marrow MRS findings in six pediatric and young adult Gaucher disease patients with age- and sex-matched controls, examining femoral neck and lumbar spine bone marrow fat fractions and bone marrow burden (BMB) scores. Separate analysis of six patients with serial imaging on ERT was performed with analysis of fat fractions, BMB scores, organ volumes, and serum chitotriosidase. RESULTS: Untreated patients had significantly lower femoral and lumbar spine fat fractions than controls (0.32 versus 0.67, p = 0.041 and 0.17 versus 0.34, p = 0.041, respectively). Total BMB scores were significantly higher in patients (8.0 versus 3.5, p = 0.015). In patients on ERT with average follow-up of 3.5 years, femoral neck fat fraction was the sole significant predictor of treatment duration (R square: 0.804, p < 0.001) when adjusted for age. Femoral neck fat fraction also correlated with lumbar spine fat fraction, liver volume and chitotriosidase (p < 0.05). MRS test-retest reliability was excellent (Pearson correlations: 0.96, 0.99; p-values <0.001). BMB inter-rater reliability was good overall with an intra-class correlation coefficient of 0.79 for total score, although lumbar spine score reliability was poor at 0.45. CONCLUSION: MRS-derived bone marrow fat fractions appear capable of detecting Gaucher disease severity and monitoring treatment-related changes as a predictor of ERT duration in pediatric and young adult patients.

Intraoperative Contrast-Enhanced Ultrasound Imaging of Femoral Head Perfusion in Developmental Dysplasia of the Hip: A Feasibility Study.

OBJECTIVES: Developmental dysplasia of the hip (DDH) is one of the most common developmental deformities of the lower extremity. Although many children are successfully treated with a brace or harness, some require intraoperative closed or open reduction and spica casting. Surgical reduction is largely successful to relocate the hip; however, iatrogenic avascular necrosis is a major source of morbidity. Recent research showed that postoperative gadolinium-enhanced magnetic resonance imaging (MRI) can depict hip perfusion, which may predict a future incidence of avascular necrosis. As contrast-enhanced ultrasound (CEUS) assesses blood flow in real time, it may be an effective intraoperative alternative to evaluate femoral head perfusion. Here we describe our initial experience regarding the feasibility of intraoperative CEUS of the hip for the assessment of femoral head perfusion before and after DDH reduction. METHODS: This single-institution retrospective Institutional Review Board-approved study with a waiver of informed consent evaluated intraoperative hip CEUS in children with DDH compared to postoperative contrast-enhanced MRI. Pediatric radiologists, blinded to prior imaging findings and outcomes, reviewed both CEUS and MRI examinations separately and some time from the initial examination both independently and in consensus. RESULTS: Seventeen patients had 20 intraoperative CEUS examinations. Twelve of 17 (70.6%) had prereduction hip CEUS, postreduction hip CEUS, and postreduction gadolinium-enhanced MRI. Seven of 12 (58.3%) were evaluable retrospectively. All CEUS studies showed blood flow in the femoral epiphysis before and after reduction, and all MRI studies showed femoral head enhancement after reduction. The CEUS and MRI for all 7 patients also showed physeal blood flow. CONCLUSIONS: Contrast-enhanced ultrasound is a feasible intraoperative tool for assessing adequate blood flow after hip reduction surgery in DDH.

Imaging of developmental dysplasia of the hip: ultrasound, radiography and magnetic resonance imaging.

Developmental dysplasia of the hip (DDH) describes a broad spectrum of developmental abnormalities of the hip joint that are traditionally diagnosed during infancy. Because the development of the hip joint is a dynamic process, optimal treatment depends not only on the severity of the dysplasia, but also on the age of the child. Various imaging modalities are routinely used to confirm suspected diagnosis, to assess severity, and to monitor treatment response. For infants younger than 4 months, screening hip ultrasound (US) is recommended only for those with risk factors, equivocal or positive exam findings, whereas for infants older than 4-6 months, pelvis radiography is preferred. Following surgical hip reduction, magnetic resonance (MR) imaging is preferred over computed tomography (CT) because MR can not only confirm concentric hip joint reduction, but also identify the presence of soft-tissue barriers to reduction and any unexpected postoperative complications. The routine use of contrast-enhanced MR remains controversial because of the relative paucity of well-powered and validated literature. The main objectives of this article are to review the normal and abnormal developmental anatomy of the hip joint, to discuss the rationale behind the current recommendations on the most appropriate selection of imaging modalities for screening and diagnosis, and to review routine and uncommon findings that can be identified on post-reduction MR, using an evidence-based approach. A basic understanding of the physiology and the pathophysiology can help ensure the selection of optimal imaging modality and reduce equivocal diagnoses that can lead to unnecessary treatment.

Imaging of non-neuronopathic Gaucher disease: recent advances in quantitative imaging and comprehensive assessment of disease involvement.

Gaucher disease is an inherited metabolic disorder resulting in deficiency of lysosomal enzyme ß-glucocerebrosidase causing the accumulation of abnormal macrophages ("Gaucher cells") within multiple organs, most conspicuously affecting the liver, spleen, and bone marrow. As the most common glycolipid metabolism disorder, it is important for radiologists encountering these patients to be familiar with advances in imaging of organ and bone marrow involvement and understand the role of imaging in clinical decision-making. The recent advent of commercially available, reliable, and reproducible quantitative MRI acquisitions to measure fat fractions prompts revisiting the role of quantitative assessment of bone marrow involvement. This manuscript reviews the diverse imaging manifestations of Gaucher disease and discusses more optimal quantitative approaches to ascertain solid organ and bone marrow involvement with an emphasis on future applications of other quantitative methods including elastography.

Proximal radius fractures in children: evaluation of associated elbow fractures.

BACKGROUND: Additional fractures occur in association with proximal radius fractures, but the extent of these secondary injuries has not been systematically assessed. OBJECTIVE: To ascertain the frequency and nature of additional fractures associated with proximal radius injuries in a large pediatric cohort. MATERIALS AND METHODS: Radiographs meeting search criteria for proximal radius fracture during a 5-year period were reviewed. Fracture characteristics and the coexistence of additional elbow fractures were recorded and analyzed. The retrospective review was compared with initial interpretation and a blinded review by two pediatric musculoskeletal radiologists. RESULTS: Four hundred ninety-four proximal radius fractures were included. The radial neck was the most common fracture site (89%). Neck fractures occurred in younger patients (mean: 7.3 years) than head fractures (mean: 13.3 years) (P<0.001). Additional elbow fractures occurred in 39%, most commonly at the olecranon (22%). Additional fractures occurred in younger patients (mean: 7.2 years) than isolated proximal radius fractures (mean: 8.5 years) (P<0.001). Elbow joint effusion and complete or displaced radius fractures were each associated with additional elbow fractures (P<0.001). When compared with initial interpretation, 25% of additional fractures were not identified on initial radiographs, of which 44% were occult retrospectively. Fracture identification demonstrated excellent inter-reader reliability (interclass correlation coefficient [ICC]: 0.88, 0.94), but joint effusion interobserver agreement was only fair (ICC: 0.52, 0.41). CONCLUSION: Proximal radius fractures in children often occur in association with other elbow fractures, most commonly involving the olecranon. Enhanced awareness of these fracture patterns, especially in the setting of joint effusion or complete and displaced radius fractures, may improve detection to guide appropriate management.

Buckle fracture of the proximal tibia in children and frequency of association with trampoline and inflatable bouncer use.

BACKGROUND: Proximal tibial buckle fractures are often called "trampoline fractures," but mechanisms are more varied. OBJECTIVE: To assess the frequency of trampoline or bouncer etiology among children with buckle fracture of the proximal tibia, characterizing demographics, alternative etiologies, and fracture patterns. MATERIALS AND METHODS: We performed retrospective chart review of mechanisms, age and gender of children with radiographs interpreted as proximal tibial buckle fracture between 2010 and 2016. Two pediatric radiologists assessed presence of cortical impaction, cortical break, increased anterior scoop deformity, and oblique extension of fracture toward the physis. We studied the associations among demographics, etiology and fracture appearance using analysis of variance and chi-square/Fisher exact tests. RESULTS: We identified 145 exams interpreted as proximal tibial buckle fracture (median age 34 months, 64% girls). Bouncing surface was the most common mechanism (44%), and 80% of those cases reported multiple people on the bouncing surface. Falls were the second most common mechanism (30%). Children injured while bouncing were older (median 41 months) than others (median 21 months, P<0.005) and more likely to have oblique extension of fracture toward the physis (P<0.05). Buckle deformity was associated with a younger age (F=8.67; P<0.01), while oblique extension to the physis and concurrent fibula fracture were associated with older age (F=18.62, P<0.001; and F=8.02, P<0.01, respectively). CONCLUSION: Trampoline use was the most common single mechanism of injury in children with proximal tibial fracture interpreted as buckle deformity. However, non-bouncing mechanisms were overall more common and occurred in a younger age group at risk for "toddler fractures."

Morel-Lavellée lesions: MRI characteristics in the pediatric patient.

BACKGROUND: A closed degloving injury is often referred to as a Morel-Lavellée lesion regardless of location despite traditionally being associated with the hip in adults. It results from a shearing injury that separates the subcutaneous layers from the fascia with fluid filling a potential space. OBJECTIVE: While the most common location and cause have been described in adults, there is limited literature in pediatric patients. We have seen pediatric Morel-Lavellée lesions commonly occurring at the knee after sports. We set out to describe the magnetic resonance imaging (MRI) characteristics. MATERIALS AND METHODS: A retrospective analysis was performed. All patients with trauma to the pelvis and lower extremities with a subcutaneous fluid collection seen on MRI were evaluated. Age, gender, mechanism of injury, time interval to imaging, and treatment were recorded. The collections were evaluated for location, size, shape and signal characteristics including the presence of fat, blood and septations. RESULTS: Twenty-one patients ages 7 to 17 years old had findings of degloving injury on MRI. The most common etiology was sports related (18/21, 85.7%). The anterior knee was most often affected (18/21, 85.7%). Lesions were ovoid and centered over the medial retinaculum (8/18, 44.4%) or lateral retinaculum (7/18, 38.9%). A capsule was weakly associated with later presentation (P=0.12). CONCLUSION: Pediatric Morel-Lavellée lesions commonly occur in a location not classically described, the anterior knee, and often after sports injury. Commonly, the collections are ovoid and always located at the subcutaneous fat/fascial interface. Recognition of specific imaging characteristics in a common location after sports injury allows for early identification. While most patients recover with conservative management, some need additional intervention with aspiration or debridement.

Normal meniscal dimensions at different patient ages-MRI evaluation.

OBJECTIVE: The purpose of this work is to evaluate the normal meniscal and tibial dimensions in relation to age and gender in different children using conventional MRI sequences. MATERIALS AND METHODS: Morphometric measurements of the menisci were retrospectively performed on knee MRIs of children (< 18 years). All knee MRIs over a 7-year period were collected. Exclusion criteria included: prior knee surgery or diseases involving the knee joint. A total of 186 children were included, 110 boys and 76 girls, with a mean age of 8.2 years (range, 0.3-17.8 years). Menisci and tibial measurement changes with age and gender as well as differences between the medial and lateral menisci were evaluated. RESULTS: The medial menisci measurements increased with age (p value < 0.001). The lateral menisci measurements increased with age (p value < 0.001), except for the coronal meniscal width (p = 0.084). Coronal and sagittal percentage of meniscal coverage of the tibia decreased with age (p < 0.001). Medial menisci have greater sagittal width and anterior horn height than lateral menisci (p value < 0.001). Lateral menisci are larger in their coronal width and height, and sagittal posterior horn height in comparison to medial menisci (p < 0.001). CONCLUSIONS: Menisci increase in all dimensions in correlation with age; except in the coronal meniscal width, which is a useful dimension to diagnose discoid meniscus on MRI, based on this, it would seem that the currently published size criteria, based on adults, could be applicable to children. The tibia has a faster rate dimension increase in correlation with age in comparison to the menisci.

More Than Epiphyseal Osteochondromas: Updated Understanding of Imaging Findings in Dysplasia Epiphysealis Hemimelica (Trevor Disease).

OBJECTIVE: The purpose of this article is to discuss approaches to imaging dysplasia epiphysealis hemimelica in the context of recent advances in the understanding of the underlying pathophysiologic profile of this entity, which may result in pain, growth disturbance, and early development of osteoarthritis. CONCLUSION: Dysplasia epiphysealis hemimelica was first characterized as a skeletal disorder with osteochondromas characteristically involving epiphyses on one side of the same lower extremity. Upper extremity involvement was subsequently recognized. Previously conceptualized as epiphyseal osteochondromatosis, recent investigations have uncovered differences between these osteocartilaginous lesions and osteochondromas.

Ultrasound features of purulent skin and soft tissue infection without abscess.

PURPOSE: Ultrasound (US) aids clinical management of skin and soft tissue infection (SSTI) by differentiating non-purulent cellulitis from abscess. However, purulent SSTI may be present without abscess. Guidelines recommend incision and drainage (I & D) for purulent SSTI, but US descriptions of purulent SSTI without abscess are lacking. METHODS: We retrospectively reviewed pediatric emergency department patients with US of the buttock read as negative for abscess. We identified US features of SSTI with adequate interobserver agreement (kappa > 0.45). Six independent observers then ranked presence or absence of these features on US exams. We studied association between US features and positive wound culture using logistic regression models (significance at p < 0.05). RESULTS: Of 217 children, 35 patients (16%) had cultures positive for pathogens by 8 h after US and 61 patients (32%) had cultures positive by 48 h after US. We found kappa > 0.45 for focal collection > 1.0 cm (κ = 0.57), hyperemia (κ = 0.57), swirling with compression (κ = 0.52), posterior acoustic enhancement (κ = 0.47), and cobblestoning or branching interstitial fluid (κ = 0.45). Only cobblestoning or interstitial fluid was associated with positive wound cultures in logistic regression models at 8 and 48 h. CONCLUSIONS: Cobblestoning or interstitial fluid on US may indicate presence of culture-positive, purulent SSTI in patients without US appearance of abscess. Although our study has limitations due to its retrospective design, this US appearance should alert imagers that the patient may benefit from early I & D.

Thoracic Neoplasms in Children: Contemporary Perspectives and Imaging Assessment.

This article focuses on commonly encountered primary lung, airway, mediastinal, and chest wall neoplasms that occur in the pediatric population. Although primary pediatric thoracic neoplasms are rare, imaging is critical in their diagnostic work-up. An overview of the latest imaging techniques specific to evaluate these pediatric thoracic neoplasms is presented across the spectrum of modalities from radiography to PET/MR imaging. In addition, the characteristic imaging appearances of these pediatric primary thoracic neoplasms are discussed with an emphasis on what the radiologist needs to know in routine clinical practice.

Musculoskeletal Traumatic Injuries in Children: Characteristic Imaging Findings and Mimickers.

Musculoskeletal traumatic injuries in children demonstrate characteristic imaging findings. The physis is the most susceptible structure to traumatic injury. The periosteum in children plays a key role in rapid bone healing and stability. The main complications of fractures in children are premature physeal closure, potential limb length discrepancy, and angular deformities. Understanding the normal bone growth, healing, and complications of pediatric fractures is crucial for appropriate imaging diagnosis. This article discusses currently available imaging modalities with up-to-date techniques, underlying mechanisms, and characteristic imaging findings of musculoskeletal traumatic injuries and mimickers encountered in daily clinical practice.

Dumbbell-Shaped Activity on Meckel's Scintigraphy Caused by Hiatal Hernia.

A 13-month-old underwent Meckel's scintigraphy to evaluate a cause of melena. The images revealed a dumbbell-shaped activity. One side of dumbbell was located in the midline lower chest, whereas another side with similar intensity was in the normal location of the stomach. A subsequent contrast CT demonstrated a large hiatal hernia.

Not all radiopaque foreign bodies shadow on ultrasound: unexpected sonographic appearance of a radiopaque magnet.

Foreign body ingestion is a common indication for imaging children. Ultrasound can be a useful adjunct to serial radiographs for evaluation of foreign bodies in the enteric tract. This case report describes a child who swallowed a single magnetic rock. Follow-up radiographs 4 days later could not determine progression of the foreign body beyond the stomach. Ultrasound was used to locate it, showing a structure with unexpected posterior reverberation artifact in the stomach. This was correlated with a similar magnet in a water bath demonstrating identical reverberation artifact. This report discusses the underlying factors for the different sonographic appearances and associated ultrasound artifacts of foreign bodies. This knowledge is important when performing sonography as adjunct modality for identification of foreign bodies in the gastrointestinal tract.

Cartilage imaging in children: current indications, magnetic resonance imaging techniques, and imaging findings.

Evaluation of hyaline cartilage in pediatric patients requires in-depth understanding of normal physiologic changes in the developing skeleton. Magnetic resonance (MR) imaging is a powerful tool for morphologic and functional imaging of the cartilage. In this review article, current imaging indications for cartilage evaluation pertinent to the pediatric population are described. In particular, novel surgical techniques for cartilage repair and MR classification of cartilage injuries are summarized. The authors also provide a review of the normal anatomy and a concise description of the advances in quantitative cartilage imaging (ie, T2 mapping, delayed gadolinium-enhanced MR imaging of cartilage, and T1rho).