Background Pulmonary infection with SARS-CoV-2 virus (severe acute respiratory syndrome coronavirus 2; COVID-19) has rapidly spread worldwide to become a global pandemic. Objective To collect paediatric COVID-19 cases worldwide and to summarize both clinical and imaging findings in children who tested positive on polymerase chain reaction testing for SARS-CoV-2. Materials and methods Data were collected by completion of a standardised case report form submitted to the office of the European Society of Paediatric Radiology from March 12 to April 8, 2020. Chest imaging findings in children younger than 18 years old who tested positive on polymerase chain reaction testing for SARS-CoV-2 were included. Representative imaging studies were evaluated by multiple senior paediatric radiologists from this group with expertise in paediatric chest imaging. Results Ninety-one children were included (49 males; median age: 6.1 years, interquartile range: 1.0 to 13.0 years, range: 9 days-17 years). Most had mild symptoms, mostly fever and cough, and one-third had coexisting medical conditions. Eleven percent of children presented with severe symptoms and required intensive unit care. Chest radiographs were available in 89% of patients and 10% of them were normal. Abnormal chest radiographs showed mainly perihilar bronchial wall thickening (58%) and/or airspace consolidation (35%). Computed tomography (CT) scans were available in 26% of cases, with the most common abnormality being ground glass opacities (88%) and/or airspace consolidation (58%). Tree in bud opacities were seen in 6 of 24 CTs (25%). Lung ultrasound and chest magnetic resonance imaging were rarely utilized. Conclusion It seems unnecessary to perform chest imaging in children to diagnose COVID-19. Chest radiography can be used in symptomatic children to assess airway infection or pneumonia. CT should be reserved for when there is clinical concern to assess for possible complications, especially in children with coexisting medical conditions.

The sacroiliac joints are involved in most cases of axial spondyloarthropathy, the first manifestation usually being sacroiliitis. A finding of sacroiliitis at radiography is the classic diagnostic hallmark of axial spondyloarthropathy. However, radiographic changes reflect structural damage rather than active inflammation, which may delay the diagnosis by several years. In the past decade, the field of spondyloarthropathy has undergone major changes, largely driven by the development of new drugs for the treatment of ankylosing spondylitis. In recent years, the Assessment of SpondyloArthritis international Society has focused on the reassessment of existing classification criteria and the development and validation of diagnostic tools to facilitate early diagnosis and assessment of treatment response. Magnetic resonance (MR) imaging is the most recent innovation and the important change with respect to the previously established classification criteria. This modality has become an integral part of managing patients with sacroiliitis. MR imaging can serve as a biomarker of disease activity, allows monitoring, and can provide guidance for the treatment of affected patients, and it will likely become even more central to the care of these patients. Familiarity with the anatomy, anatomic variants, and physiologic changes of the sacroiliac joints is important for correctly interpreting findings and avoiding misdiagnosis.

The term juvenile idiopathic arthritis (JIA) encompasses a group of arthritides of unknown cause that begin before 16 years of age and last for at least 6 weeks. Temporomandibular joint (TMJ) involvement has been described in up to 87% of children with JIA and has been associated with all JIA subtypes. TMJ involvement is difficult to detect clinically. In one study, 71% of JIA patients with active TMJ synovitis were asymptomatic and 63% had normal physical examination results. Moreover, the main growth center of the mandible is located in the condyle, separated from the joint space by only a thin layer of fibrocartilage. This makes mandibular growth vulnerable to arthritic changes, eventually resulting in facial asymmetry and retrognathia. Therefore, early detection and treatment of TMJ arthritis are paramount to preserving motility and preventing deformity. As clinical symptoms and physical examination results are not good markers of TMJ involvement, imaging plays a key role in diagnosis and treatment monitoring. Magnetic resonance imaging is the technique of choice for the study of TMJ arthritis. It has the advantages of displaying both soft tissue and bone, is the most sensitive technique for detecting acute synovitis, and is the only one able to demonstrate bone marrow edema. In addition, it allows the assessment of changes to the joint over time and evaluation of the effectiveness of therapeutic interventions. RSNA, 2017.

Background COVID-19 is a novel coronavirus infection that can cause a severe respiratory illness and has been declared a pandemic by the World Health Organization (WHO). Because children appear to be less severely affected than adults, their imaging appearances have not been extensively reported. Objective To systematically review available literature regarding imaging findings in paediatric cases of COVID-19. Materials and methods We searched four databases (Medline, Embase, Cochrane, Google Scholar) for articles describing imaging findings in children with COVID-19. We included all modalities, age <18 years, and foreign language articles, using descriptive statistics to identify patterns and locations of imaging findings, and their association with outcomes. Results Twenty-two articles were included, reporting chest imaging findings in 431 children, of whom 421 (97.7%) underwent CT. Criteria for imaging were lacking. At diagnosis, 143/421 (34.0%) had a normal CT. Abnormalities were more common in the lower lobes and were predominantly unilateral. The most common imaging pattern was ground-glass opacification (159/255, 62.4%). None of the studies described lymphadenopathy, while pleural effusions were rare (three cases). Improvement at followup CT imaging (3-15 days later) was seen in 29/100 (29%), remained normal in 25/100 (25%) and progressed in 9/100 (9%). Conclusion CT chest findings in children with COVID-19 are frequently normal or mild. Lower lobes are predominantly affected by patchy ground-glass opacification. Appearances at follow-up remain normal or improve in the majority of children. Chest CT imaging adds little to the further management of the patient and should be reserved for severe cases or for identifying alternative diagnoses.

LVNC is a cardiac disease of emerging importance, and imaging has a key role in its diagnosis. Accordingly, radiologists should be familiar with LVNC imaging findings to realize an accurate diagnosis.