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.

MRI of the temporomandibular joint in children with juvenile idiopathic arthritis: protocol and findings.

Contrast-enhanced magnetic resonance imaging (MRI) is the technique of choice for diagnosis and monitoring of temporomandibular joint (TMJ) disorders in patients with juvenile idiopathic arthritis (JIA), as it is able to visualize both soft tissue and osteochondral changes. Approximately 40% of children with JIA develop inflammatory and chronic osteochondral changes observable on imaging, which if left untreated can lead to significant facial growth impairment, including facial asymmetry and retrognathia. MRI of the TMJ plays a paramount role in diagnosis and treatment monitoring in JIA since early signs of TMJ involvement are difficult to detect clinically and with physical examination. Findings of TMJ arthritis may be classified into acute and chronic domains. Early or acute manifestations include joint effusion, bone marrow edema, synovial thickening, and increased joint enhancement. With disease progression, there are characteristic osteochondral changes, including deformity of the mandibular condyle with shortening of the mandibular ramus, bone erosions, and disk abnormalities. In this pictorial essay, we describe a consensus MRI protocol for the study of the TMJ and illustrate the degree of normal and pathological MRI findings using currently available MRI scoring systems of the TMJ developed for JIA.

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.

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.

Chronic lesser tuberosity avulsion in an adolescent with an associated biceps pulley injury.

We report a case of a 15-year-old boy with chronic intermittent left shoulder pain due to an undiagnosed lesser tuberosity avulsion fracture, an associated biceps pulley injury and intra-articular dislocation of the long head of the biceps tendon. Lesser tuberosity avulsion fractures are rare injuries that are difficult to detect on clinical exam and radiographically, which may lead to delayed diagnosis and chronic shoulder instability. Few reports describe dislocations or subluxations of the biceps tendon in association with lesser tuberosity avulsions in children. We utilize this case to emphasize the importance of MR not only in detecting lesser tuberosity avulsions, but also in evaluating biceps pulley injuries, which are a rarely reported, but clinically important, association.

Imaging of temporomandibular joint abnormalities in juvenile idiopathic arthritis with a focus on developing a magnetic resonance imaging protocol.

Inflammation and damage in the temporomandibular joint (TMJ) often develop without clinical symptoms but can lead to severe facial growth abnormalities and impaired health-related quality of life, making early diagnosis of TMJ changes crucial to identify. Inflammatory and osteochondral changes detectable through magnetic resonance imaging (MRI) occur in TMJs of approximately 40% of children with juvenile idiopathic arthritis (JIA), and no other imaging modality or physical method of examination can reliably detect these changes. Therefore contrast-enhanced MRI is the diagnostic standard for diagnosis and interval monitoring of JIA. However the specific usage of MRI for TMJ arthritis is not standardized at present. There is a recognized need for a consensus effort toward standardization of an imaging protocol with required and optional sequences to improve detection of pathological changes and shorten study time. Such a consensus imaging protocol is important for providing maximum information with minimally necessary sequences in a way that allows inter-site comparison of results of clinical trials and improved clinical management. In this paper we describe the challenges of TMJ imaging and present expert-panel consensus suggestions for a standardized TMJ MRI protocol.

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.

Sonographic spinal imaging of normal anatomy, pathology and magnetic growing rods in children.

The wide availability of ultrasound, along with its lack of ionizing radiation burden and need for sedation for most exams, often make sonography the first line in the imaging evaluation of children. The developing osseous anatomy of the spine in young infants provides a distinct window allowing for a detailed depiction of the spinal canal and its contents, which is not present in older children or adults. Here we review the clinical indications, sonographic technique, normal anatomy and pathology for imaging the lumbosacral spine in neonates and young infants. Additionally, we review the procedure for ultrasound assessment of the lengthening of magnetically controlled growing spinal rods, which allows orthopedists and radiologists to evaluate the effectiveness of distraction procedures of this hardware without the use of ionizing radiation.

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.

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.

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.

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.

Pediatric neuropathic arthropathy initially masquerading as inflammatory arthritis.

We describe a case of neuropathic arthropathy in the knees of a child eventually diagnosed with a hereditary sensory and autonomic neuropathy. The child was initially treated for rheumatologic disease at an outside institution. History and neurological workup revealed a neuropathy most consistent with hereditary sensory and autonomic neuropathy type II. Hereditary sensory and autonomic neuropathy should be considered in the differential diagnosis of children with joint abnormalities whose workup for an inflammatory arthropathy is negative and who exhibit diminished pain sensation on examination.

Diagnostic Accuracy Study of the Pediatric-Specific Ultrasound Scoring System for the Knee Joint in Children With Juvenile Idiopathic Arthritis.

OBJECTIVE: We undertook this study to validate the Pediatric Arthritis Ultrasound Scoring System for the knee joint (PAUSS-knee) in children with juvenile idiopathic arthritis (JIA). METHODS: Children with JIA were enrolled to prospectively receive a musculoskeletal ultrasound (MSUS) examination of the knee and a physical examination to determine presence/absence of clinical arthritis. MSUS images were scored using the PAUSS-knee, a semiquantitative MSUS scoring system (0-3, normal to severe) for B-mode and power Doppler mode. In addition to MSUS, a subset of participants also received magnetic resonance imaging (MRI) of the knee, which was scored according to the combined Juvenile Arthritis MRI Scoring (JAMRIS) system. Spearman's correlations (rs ) were used to calculate associations between variables. Test characteristics of the PAUSS-knee were calculated with MRI as the reference standard. Inflammatory biomarkers were assessed in synovial fluid from involved knees. RESULTS: Eighty children with JIA contributed 112 MSUSs and 25 MRIs of the knee. Of the knees, 41% (n = 46) had clinical evidence of arthritis. The B-mode PAUSS-knee score moderately correlated with clinically determined arthritis (rs = 0.54, P < 0.001) and strongly correlated with the JAMRIS score (rs = 0.75, P < 0.001). Compared with MRI, the area under the curve for the B-mode PAUSS-knee was 0.92. For a cutoff of >1, the B-mode PAUSS-knee had a sensitivity of 83% and specificity of 82%. Biomarker analysis indicates that interleukin-2R levels correlate with PAUSS score. CONCLUSION: Our data indicate that the PAUSS-knee has excellent accuracy for the diagnosis of arthritis when compared with MRI. The PAUSS-knee has the potential to effectively inform JIA medical decision-making in real time.

Systematic calibration reduces sources of variability for the preliminary OMERACT juvenile idiopathic arthritis MRI- sacroiliac joint score (OMERACT JAMRIS-SIJ).

OBJECTIVE: To determine whether systematic calibration enhances scoring proficiency of the OMERACT juvenile idiopathic arthritis MRI-Sacroiliac Joint score (JAMRIS-SIJ) and whether contrast-enhancement enhances its performance. METHODS: MRI SIJ scans of 50 cases with juvenile spondyloarthritis were scored by 7 raters after calibration with 3 different knowledge transfer tools. RESULTS: Calibrated readers achieved greater reliability for scoring certain inflammatory and structural lesions. Sensitivity and reliability for scoring inflammatory lesions was greater on fluid-sensitive compared to contrast-enhanced sequences. CONCLUSION: Systematic calibration should be implemented prior to the use of JAMRIS-SIJ for clinical trials. It is unlikely that contrast-enhanced MRI will improve the performance of this method.