Determination of Relative Weightings for Sacroiliac Joint Pathologies in the OMERACT Juvenile Arthritis Magnetic Resonance Imaging Sacroiliac Joint Score.

This study aims to determine the relative weights (point value) of items of the juvenile idiopathic arthritis magnetic resonance imaging-sacroiliac joint scoring system (JAMRIS-SIJ). An adaptive multicriteria decision analysis was performed using the 1000Minds web application to determine the relative weights of the items in the JAMRIS-SIJ inflammation and damage domains. Experts in imaging and rheumatology independently completed a conjoint analysis survey (CAS) to determine the point value of the measurement items of the JAMRIS-SIJ. Each CAS survey question asked the expert to compare two hypothetical patient profiles, which were otherwise similar but different at two items at a time, and to select which item showed a more severe stage of inflammation or osteochondral damage. In addition, experts ranked 14 JAMRIS-SIJ grade only or image + grade patient vignettes while blinded to the CAS-derived weights. The validity of the weighted JAMRIS-SIJ was tested by comparing the expert CAS-weighted score and the image + grade ranking method. Seventeen experts completed the CAS (11 radiologists and 6 rheumatologists). Considering the point value for inflammation domain items, osteitis (24.7%) and bone marrow edema (24.3%) had higher group-averaged percentage weights compared to inflammation in erosion cavity (16.9%), joint space enhancement (13.1%), joint space fluid (9.1%), capsulitis (7.3%), and enthesitis (4.6%). Similarly, concerning the damage domain, ankylosis (41.3%) and erosion (25.1%) showed higher group-averaged weights compared to backfill (13.9%), sclerosis (10.7%), and fat metaplasia lesion (9.1%). The Spearman correlation coefficients of the CAS-weighted vignette order and unweighted JAMRIS-SIJ grade only order vignettes for all experts were 0.79 for inflammation and 0.80 for damage. The correlations of image vignettes among imaging experts to CAS were 0.75 for inflammation and 0.90 for damage. The multicriteria decision analysis identified differences in relative weights among the JAMRIS-SIJ measurement items. The determination of the relative weights provided expert-driven score scaling and face validity for the JAMRIS-SIJ, enabling the future evaluation of its longitudinal construct validity.

Imaging the pediatric anterior cruciate ligament: not little adults.

An increased incidence of anterior cruciate ligament (ACL) injuries in children over the last few decades has led to a corresponding increase in ACL reconstruction procedures in children. In this review, we will illustrate unique features seen when imaging the ACL in children versus adults. After briefly reviewing relevant normal ACL anatomy, we will review imaging findings of congenital ACL dysplasia. This is followed by a discussion of imaging ACL avulsions. Lastly, we will review the different types of ACL reconstruction procedures performed in skeletally immature children and their post-operative appearances.

Ultrasound versus magnetic resonance imaging of soft-tissue lesions: competitive or complementary?

Soft-tissue lumps and bumps are a common referral for imaging in children and adolescents. The etiology of these lesions includes benign non-tumorous lesions, as well as benign and malignant tumors. Some of these lesions have a characteristic imaging appearance but others do not and require tissue sampling to make a diagnosis. MRI typically provides the best overall characterization of soft-tissue masses; however, in some cases US provides complementary information to that provided by MRI that can help make a diagnosis.

Pearls and Pitfalls of Imaging of the Developing Pediatric Skeleton: Differentiating Normal and Pathology With MRI.

Developmental changes occurring in the pediatric skeleton throughout childhood cause imaging appearances that may be confused with pathology. Knowledge of the typical pattern of red to yellow bone marrow conversion and areas of normal developmental irregular ossification is essential for radiologists interpreting musculoskeletal imaging in children to avoid mistaking normal findings for disease. Here we review the normal conversion of hematopoietic to yellow marrow on pediatric MRI and illustrate how MRI can distinguish the normal areas of irregular ossification from various pathology that can occur at and around growth centers in the developing skeleton.

Pediatric Osteosarcoma: Pearls and Pitfalls.

Osteosarcoma is a malignant bone tumor most commonly presenting in children. It has a bimodal distribution with a peak incidence occurring during the ages of 10-14 years old and in adults greater than age 65. The first peak of osteosarcoma correlates with the increased proliferation of bone during the pubertal growth period. Osteosarcoma most frequently presents with localized bone pain, swelling, and an antalgic gait. The patient may attribute symptoms to trauma or strenuous exercise, causing the patient to be managed conservatively. In these cases, the pain persists and eventually leads to further evaluation. The most common type of osteosarcoma is the conventional high-grade osteosarcoma. For conventional osteosarcoma, the diagnosis is typically made or strongly suggested based upon the initial radiographic appearance. Other types of osteosarcomas include low grade central, telangiectatic, small-cell, surface and intracortical. Consequently, it is important for radiologists to be aware of these subtypes and the imaging features that differentiate them from other etiologies to prevent a delay in treatment.

MR Imaging of Osteoid Osteoma: Pearls and Pitfalls.

Osteoid osteoma (OO) is a benign bone neoplasm consisting of a central prostaglandin-secreting nidus surrounded by a zone of reactive sclerosis. The diagnosis is suspected in children and young adults with longstanding nighttime pain that is relieved by salicylates or nonsteroidal anti-inflammatory drugs. Early studies suggested that computed tomography had a higher sensitivity and specificity in the diagnosis of OO compared to magnetic resonance imaging (MRI). More recent literature suggests MRI done with dynamic postcontrast imaging to be equal to or slightly better at detecting the nidus of OOs, particularly the ones in atypical locations. Being able to evaluate for OO utilizing MRI is important given that the majority of these lesions occur in younger patients, in whom there is greater concern to limit ionizing radiation. Furthermore, patients with atypical OOs often receive an MRI if radiographs are not suggestive of the diagnosis. Therefore, it is important for radiologists to be aware of the imaging features that can help make the diagnosis on MRI.

Magnetic resonance imaging evaluation of osteoid osteoma: utility of the dark rim sign.

BACKGROUND: While typical patterns of osteoid osteoma have been described on CT, MRI findings can overlap among different diseases, and atypical patterns exist. In this study, we assessed the presence of a novel dark rim sign and its utility in the MRI diagnosis of osteoid osteoma. OBJECTIVE: The purpose of this retrospective study was to assess the utility of the dark rim sign seen on MRI in children with osteoid osteoma. MATERIALS AND METHODS: MRI studies from 36 pediatric patients with osteoid osteoma and a control group of patients with either osteomyelitis or stress fracture were analyzed and then compared for the presence of the dark rim sign. Patients from the osteoid osteoma group were further divided based on nidus location and evaluated for the presence of the dark rim sign. RESULTS: The relationship between the dark rim sign and osteoid osteoma was statistically significant (P<0.001). A dark rim sign was identified in 25 of the 36 patients with osteoid osteoma. None of the control patients had a dark rim sign. The dark rim sign had 69.4% sensitivity, 100% specificity, 100% positive predictive value and 72.5% negative predictive value for detecting osteoid osteoma. The relationship between dark rim sign and nidus location was statistically significant (P<0.001) such that endosteal and medullary osteoid osteomas were more likely to have a dark rim sign than intracortical osteoid osteomas. CONCLUSION: When the nidus of an osteoid osteoma is in an endosteal or medullary location, the dark rim sign may aid in the diagnosis.

Physeal bridges: causes, diagnosis, characterization and post-treatment imaging.

The cartilaginous primary physis, or growth plate, at the end of long bones in children allows for longitudinal bone growth. A variety of insults to the physis can lead to physeal bridge formation, which in turn can lead to limb-shortening and angular deformities. This paper begins with a description of the causes, risk factors and mechanisms by which bridges form. Then it reviews the use of imaging in the diagnosis and characterization of bridges and in the evaluation of treatment and post-treatment complications. It is important for radiologists taking care of children to be aware of the indirect and direct imaging findings of physeal bridges to aid in their diagnosis, to be able to characterize bridges as part of preoperative planning, and to know the imaging finding of post-resection complications.

Perihepatic abscesses caused by dropped appendicoliths in a child.

A dropped appendicolith is a well-known complication of laparoscopic appendectomy that may occur because of stone expulsion from the appendix, before or during surgery, and typically manifests as a focal, subcentimeter area of high attenuation with or without associated abscess. Dropped appendicoliths may act as niduses for infection and may result in the future development of abscess formation. We report the case of a 10-year-old pediatric patient who developed 2 perihepatic abscesses caused by 2 appendicoliths that were inadvertently dropped during laparoscopic surgery.

Non-Catheter-related Venous Thromboembolism in Children: Imaging Review from Head to Toe.

Non-catheter-related venous thromboembolism (VTE) is less common in children than in adults. Although the presence of a central venous catheter is the most common cause of venous thrombosis in children, infection and inflammation, malignancy, hypercoagulability, dehydration, and certain sites of normal variant and pathologic anatomic narrowing all predispose to VTE in children. The mortality and morbidity of VTE vary according to the underlying cause, including whether malignancy is present. Various modalities including ultrasonography (US), computed tomography, and magnetic resonance imaging can be used to image VTE, with some modalities better suited to particular parts of the body and clinical scenarios than others. When feasible, US is the initial test of choice for the diagnosis of VTE. US findings of acute VTE include a dilated noncompressible vein, intraluminal echoes, lack of color flow, and abnormal spectral venous waveforms. Serial US examinations are useful for monitoring patient response to therapy; a normal compressible vein will be seen after complete resolution of thrombus, and chronic venous changes including wall thickening, intraluminal webs, and phleboliths, which are readily apparent at US. Accurate and timely diagnosis of VTE must take into account the various advantages and disadvantages of each modality including speed, accuracy, availability, exposure to ionizing radiation, and need for sedation, as well as the clinical stability and transportability of the child. This article reviews some of the more common causes of VTE in children (other than those related to a central venous catheter) according to body part and discusses the associated imaging findings. ©RSNA, 2017.

Imaging of Acute Pelvic Pain in Girls: Ovarian Torsion and Beyond☆.

Identifying the etiology of acute pelvic pain in girls is often clinically challenging. Particularly in young girls, it is often difficult to determine if acute pelvic symptoms are originating from a gynecologic source or from a genitourinary or gastrointestinal etiology based on the child's clinical examination alone. Therefore, imaging plays a key role in establishing a diagnosis and in directing medical and surgical treatment. Pediatric gynecologic conditions, which can present acutely with pain or mass or both include ovarian torsion, hematometrocolpos, pelvic inflammatory disease, inguinal hernias containing an ovary or the uterus or both, adnexal cysts, pregnancy, vaginal foreign bodies, and ovarian vein thrombosis. Sources of pelvic pain in girls from nongynecologic etiologies include appendicitis, distal ureterolithiasis, and Crohn's disease. Owing to the lack of ionizing radiation, widespread availability, and lack of need for sedation, gray scale, with color Doppler ultrasound examination is often the initial imaging obtained when there is suspicion of gynecologic pathology. Radiographs of the abdomen and pelvis are commonly used in the acute setting, when there is concern for a bowel obstruction or free intraperitoneal air. Cross-sectional imaging with computed tomography or magnetic resonance imaging is used, when the diagnosis remains unknown and to clarify findings found on ultrasound and radiographs. Correctly identifying and diagnosing the causes of acute pelvic pain in girls is crucial for the care of these patients. Here, we review the spectrum of causes of acute pelvic pain in female infants to teens with emphasis on imaging approach and age-related characteristics.

Pediatric cholangiopathies: diseases of the gallbladder and biliary tract.

Pediatric gallbladder and bile duct disease encompasses a broad spectrum of processes, from congenital to developmental to neoplastic. We describe normal pediatric biliary anatomy and summarize the most common pathologic entities, with a focus on non-invasive imaging techniques and findings. Ultrasound is the first-line imaging modality in children with suspected biliary pathology based on its widespread availability, cost effectiveness, and lack of ionizing radiation. MRI and MRCP are often used for further evaluation in cases of diagnostic uncertainty and for surgical planning.

Multifocal tenosynovial giant cell tumors in a child with Noonan syndrome.

Noonan syndrome is a genetic disorder with variable expression of distinctive facial features, webbed neck, chest deformity, short stature, cryptorchidism and congenital heart disease. The association of Noonan syndrome and giant cell granulomas of the mandible is widely reported. However, Noonan syndrome may also be associated with single or multifocal tenosynovial giant cell tumors, also referred to as pigmented villonodular synovitis. We report a child with Noonan syndrome, giant cell granulomas of the mandible and synovial and tenosynovial giant cell tumors involving multiple joints and tendon sheaths who was initially misdiagnosed with juvenile idiopathic arthritis. It is important for radiologists to be aware of the association of Noonan syndrome and multifocal giant cell lesions, which can range from the more commonly described giant cell granulomas of the mandible to isolated or multifocal intra- or extra-articular tenosynovial giant cell tumors or a combination of all of these lesions.

Imaging assessment of patellar instability and its treatment in children and adolescents.

Transient patellar dislocation is a common entity in children and adolescents, characterized by lateral dislocation of the patella, usually with spontaneous reduction. Many predisposing conditions have been described, including trochlear dysplasia, excessive lateral patellar tilt, patella alta and lateralization of the tibial tuberosity. Associated injuries are bone bruises of the patella and lateral femoral condyle, tears of the medial retinaculum that include the medial patellofemoral ligament (MPFL), tears of the vastus medialis obliquus muscle, injuries of articular cartilage, and intra-articular bodies. Children who are refractory to conservative management, have a large cartilage defect, or are at substantial risk for recurrent dislocations are candidates for surgical procedures to prevent future dislocations. Procedures can include MPFL repair or reconstruction, tibial tubercle repositioning and lateral retinacular release. The purpose of this review is to illustrate the imaging findings of transient patellar dislocation in the acute setting, the normal imaging appearance after surgical intervention, and post-surgical complications.

Langerhans cell histiocytosis of the digestive tract identified on an upper gastrointestinal examination.

Langerhans cell histiocytosis (LCH) with involvement of the gastrointestinal tract is rare and typically identified in patients with systemic disease. We describe a 16-month-old girl who initially presented with bilious vomiting, failure to thrive and a rash. An upper gastrointestinal (GI) examination revealed loss of normal mucosal fold pattern and luminal narrowing within the duodenum, prompting endoscopic biopsy. Langerhans cell histiocytosis of the digestive tract was confirmed by histopathology. A skeletal survey and skin biopsy identified other systemic lesions. Although uncommon, it is important to consider LCH in the differential diagnosis for gastrointestinal symptoms of unclear origin, especially when seen with concurrent rash. Findings of gastrointestinal involvement on upper GI examination include loss of normal mucosal fold pattern and luminal narrowing in the few published case reports.

A rare case of cystic ganglionosis in a child with associated imaging findings.

Ganglia are benign soft tissue masses that are found adjacent to joints and tendons. They can be multifocal but they are rarely more numerous than a few around any given joint. "Cystic ganglionosis" has been used to describe a condition in which multifocal and extensive ganglia are present. We present a rare case of cystic ganglionosis in a Caucasian girl with clinical symptoms detected at 6 months of age. To the authors' knowledge, only a single other case report of cystic ganglionosis is documented in the English medical literature. The ganglia in this case are more extensive, manifested at an earlier age and caused erosions of multiple bones, a rarely observed complication of ganglia. Additionally, radiograph, MR and sonographic images collected over 9 years time allows for a detailed description of the imaging characteristics of this case of cystic ganglionosis, and offers unique insight into the natural history of this diagnosis. Extensive ganglia in multiple locations in a young child should alert clinicians to the possibility of cystic ganglionosis. Disease progression may lead to deleterious effects on bone warranting the use of maintenance imaging and possibly surgical resection of symptomatic lesions.

Post-operative imaging of anterior cruciate ligament reconstruction techniques across the spectrum of skeletal maturity.

Due to an increased frequency of anterior cruciate ligament (ACL) injuries in young patients and improved outcomes in athletic performance following ACL reconstruction, surgery is increasingly being performed across the spectrum of skeletal maturity. We present a review of the range of reconstruction techniques performed in skeletally immature patients (physeal sparing techniques, which may involve epiphyseal tunnels or the utilization of an iliotibial band autograft), those performed in patients nearing skeletal maturity (transphyseal techniques), and the more conventional ACL reconstruction techniques performed in skeletally mature adolescents. It is important that radiologists be aware of the range of techniques being performed throughout the spectrum of skeletal maturity in order to accurately characterize the expected post-operative appearance as well as to identify complications, including those unique to this younger population.

Imaging neonates and children with Pierre Robin sequence before and after mandibular distraction osteogenesis: what the craniofacial surgeon wants to know.

Pierre Robin sequence is characterized by micrognathia and glossoptosis causing upper airway obstruction. Mandibular distraction osteogenesis is a mandibular lengthening procedure performed in neonates and children with Pierre Robin sequence to alleviate airway compromise. This pictorial review demonstrates the role of imaging in the preoperative and postoperative assessment of these children. It is important for pediatric radiologists to know what information about the mandible and airway the craniofacial surgeon needs from preoperative imaging and to identify any complications these children may encounter after surgery.