The Many Faces of Pediatric Chronic Recurrent Multifocal Osteomyelitis (CRMO): A Practical Location- and Case-Based Approach to Differentiate CRMO From Its Mimics.

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disease of childhood and adolescence characterized by episodic bone pain. Diagnosis relies heavily on whole-body MRI and is made by excluding a wide variety of other disorders with overlapping imaging features, depending on location, marrow distribution, and the presence or absence of multifocality. We present an overview of the clinical and imaging features of CRMO and, through various clinical scenarios, provide tips for tailoring the differential diagnosis based on location and distribution of encountered abnormalities. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY STAGE: 3.

Anatomy and injuries of the pediatric wrist: beyond the basics.

Ligamentous injuries of the pediatric wrist, once thought to be relatively uncommon, are increasingly recognized in the context of acute high-energy mechanism trauma and chronic axial loading, including those encountered in both recreational and high-performance competitive sports. Recent advances in MR-based techniques for imaging the pediatric wrist allow for sensitive identification of these often radiographically occult injuries. Detailed knowledge of the intrinsic and supportive extrinsic ligamentous complexes, as well as normal developmental anatomy and congenital variation, are essential to accurately diagnose injuries to these structures. Early identification of ligamentous injury of the pediatric wrist is essential within the conservative treatment culture of modern pediatric orthopedics because treatment of these lesions often necessitates surgery, and outcomes often depend on early and sometimes aggressive intervention. In this article, we review MR arthrogram technique and pediatric wrist anatomy, and correlate appearances on MR and selected ligamentous pathologies of the pediatric wrist.

US Evaluation of Juvenile Idiopathic Arthritis and Osteoarticular Infection.

Juvenile idiopathic arthritis (JIA) and osteoarticular infection can cause nonspecific articular and periarticular complaints in children. Although contrast material-enhanced magnetic resonance imaging is the reference standard imaging modality, musculoskeletal ultrasonography (US) is emerging as an important adjunct imaging modality that can provide valuable information relatively quickly without use of radiation or the need for sedation. However, diagnostic accuracy requires a systemic approach, familiarity with various US techniques, and an understanding of maturation-related changes. Specifically, the use of dynamic, Doppler, and/or multifocal US assessments can help confirm sites of disease, monitor therapy response, and guide interventions. In patients with JIA, ongoing synovial inflammation can lead to articular and periarticular changes, including synovitis, tenosynovitis, cartilage damage, bone changes, and enthesopathy. Although these findings can manifest in adult patients with rheumatoid arthritis, important differences and pitfalls exist because of the unique changes associated with an immature and maturing skeleton. In patients who are clinically suspected of having osteoarticular infection, the inability of US to evaluate the bone marrow decreases its sensitivity. Therefore, the US findings should be interpreted with caution because juxtacortical inflammation is suggestive, but neither sensitive nor specific, for underlying osteomyelitis. Similarly, the absence of a joint effusion makes septic arthritis extremely unlikely but not impossible. US findings of JIA and osteoarticular infection often overlap. Although certain clinical scenarios, laboratory findings, and imaging appearances can favor one diagnosis over the other, fluid analysis may still be required for definitive diagnosis and optimal treatment. US is the preferred modality for fluid aspiration and administering intra-articular corticosteroid therapy. © RSNA, 2017.

Brachial plexus birth palsy: multimodality imaging of spine and shoulder abnormalities in children.

OBJECTIVE. The purpose of this article is to provide a comprehensive overview of the imaging of brachial plexus palsy, including both pathologic conditions of the spine and shoulder and clinical background and management. CONCLUSION. Brachial plexus birth palsy can result in permanent disability and limb deformity. Identifying the lesion type and associated sequelae is important in clinical management aimed at optimizing outcome. The imaging algorithms used are guided by clinical presentation and are designed to assess the extent of injury to guide possible surgical intervention.

Pediatric CT: strategies to lower radiation dose.

OBJECTIVE: The introduction of MDCT has increased the utilization of CT in pediatric radiology along with concerns for radiation sequelae. This article reviews general principles of lowering radiation dose, the basic physics that impact radiation dose, and specific CT integrated dose-reduction tools focused on the pediatric population. CONCLUSION: The goal of this article is to provide a comprehensive review of the recent literature regarding CT dose reduction methods, their limitations, and an outlook on future developments with a focus on the pediatric population. The discussion will initially focus on general considerations that lead to radiation dose reduction, followed by specific technical features that influence the radiation dose.

MR imaging of the paediatric foot and ankle.

Radiography is the mainstay for initial evaluation of paediatric foot and ankle pathology. MRI is the preferred exam for further characterisation of the majority of these conditions. The modality features high sensitivity and specificity for this purpose with few exceptions. Findings on MRI will often dictate patient referral and further management, and are frequently required for surgical planning. This article will provide an overview of a variety of pathologies that afflict the foot and ankle in children. These include tarsal coalition, osteochondral lesions, osteonecrosis, osteochondroses, stress fractures, osteomyelitis, inflammatory arthritis, neoplasms of bone and soft tissue, and foreign bodies. Their respective imaging manifestations on MRI are the focus of the paper. Technical parameters and marrow signal variation are also discussed.

MRI of pediatric patients: Part 1, normal and abnormal cartilage.

OBJECTIVE: Cartilage development has a profound impact on musculoskeletal growth. The objective of this article is to offer insights about the maturation of hyaline cartilage through MRI. We begin by briefly describing the molecular make up of hyaline cartilage. We will then follow with a discussion of the basic principles to apply to optimize hyaline cartilage imaging. The remainder of the article will focus on the MR appearances of the distinct histologic types of hyaline cartilage, normal variations in cartilage development, and the sequelae of cartilage injury on normal skeletal development. CONCLUSION: Knowledge of the normal and abnormal appearances of hyaline cartilage on MRI of pediatric patients will allow readers to avoid mistaking the changes associated with skeletal maturation for pathologic findings.

MRI of pediatric patients: Part 2, normal variants and abnormalities of the knee.

OBJECTIVE: The purpose of this article is to discuss MRI of the pediatric knee and familiarize the reader with conditions encountered in the pediatric population. Clinical scenarios are included to convey important concepts and to orient the learner to normal variants and abnormalities of the pediatric knee. The conditions discussed include, but are not limited to, distal femoral metaphysial irregularity, isolated popliteus tendon avulsion, juvenile idiopathic arthritis, and discoid meniscus. CONCLUSION: The knee is the joint that is most commonly imaged by MRI in children. Injury patterns and signs of other pathologic processes seen in skeletally immature patients are different from those seen in adults. Interpreting pediatric knee MRI studies may be a challenge for those unfamiliar with the evolving patterns of normal development and of the signs of conditions that are more prevalent in children. Through case scenarios, this article describes and provides images that depict conditions commonly encountered in the pediatric knee. Most of the described normal findings and abnormalities are more prevalent in the pediatric population than in adults, and a few of the conditions are, in fact, unique to pediatric patients.

Imaging bithalamic pathology in the pediatric brain: demystifying a diagnostic conundrum.

OBJECTIVE: The thalami are subject to multiple insults including metabolic and toxic phenomena, acute demyelination, infection, infarction, hemorrhage and neoplastic involvement. The purpose of this article is to review the neuroimaging approach, classification, and imaging of bilateral thalamic lesions with histopathology correlation and application of advanced techniques. CONCLUSION: Neuroimaging of abnormal pediatric thalami uses conventional MRI sequences and advanced techniques to characterize lesions. Although there is considerable imaging overlap, a tailored approach can facilitate diagnosis and management.

Imaging of chronic recurrent multifocal osteomyelitis: self-assessment module.

The educational objectives for this self-assessment module are for the participant to exercise, self-assess, and improve his or her understanding of both the imaging and clinical findings of chronic recurrent multifocal osteomyelitis (CRMO).

Epidermoid Cyst of the Testicle.

We describe the case of a 13-year-old boy with testicular epidermoid cyst who presented with a painless testicular mass. Epidermoid cyst of the testis is a benign, non-teratomatous tumor. It is often possible to make the diagnosis preoperatively, combining typical sonographic features with normal biochemical tumor markers. Preoperative diagnosis will allow for testis-sparing surgery and prevent unnecessary orchiectomy.

Reduction of Small Bowel Instussuception Caused by Jejunal Hamartomatous Polyps Documented by Intraoperative Video.

We present a case of non-Peutz Jegher hamartomatous polyps causing jejuno-jejunal intussusception and small bowel obstruction in a pediatric patient. In addition, we also provide an intraoperative video of the intussusception reduction process. Polyps causing small bowel intussusception are uncommon but not rare. However, we could not find in the medical literature any videos of the intussusception reduction process. We feel this case report, the discussion provided, and the intraoperative video correlation will offer a unique educational perspective to this disease entity. In addition, this case report will also show the importance of considering small bowel intussusception in the differential of a child who presents with vague but persistent abdominal symptoms.