Objective. Temporomandibular joint (TMJ) arthritis in children with juvenile idiopathic arthritis (JIA) is extremely common but frequently asymptomatic. Magnetic resonance imaging (MRI) with contrast remains the gold standard for identifying TMJ arthritis in JIA. A reliable scoring system with published MRI examples of typical acute and chronic TMJ arthritis changes will be invaluable for future prospective treatment trials of TMJ arthritis in JIA. Methods. MRIs were collected from routine clinical studies assessing TMJ arthritis in JIA. Representative images were selected for publication to depict acute (synovial fluid, bone marrow edema, and synovial enhancement) and chronic (pannus, disc derangement, and condylar head flattening and erosions) TMJ arthritis findings. A preliminary MRI-based scoring system for assessing degrees of acute and chronic TMJ arthritis was developed and tested for inter-and intrareader reliability. Results. TMJ MRIs representative of acute and chronic TMJ arthritis in JIA were selected from among thousands taken (>500 TMJ MRI studies annually at Children's of Alabama) since September 2007. Moreover, computed tomography scans depicting select bony changes (osteophyte formation, micrognathia) were chosen for publication. A description of the MRI protocol for assessing TMJ arthritis is included. A preliminary scoring system weighted for degree of acute and chronic TMJ arthritis MRI findings was found to have substantial inter-and intrareader reliability. Conclusion. A published set of MRIs depicting representative acute and chronic changes will help establish a standardized scoring system to assess TMJ arthritis in children with JIA. Future validation will aid in assessing improvement during treatment trials of TMJ arthritis.

Background Human metapneumovirus (HMPV) was identified in 2001 and is a common cause of acute respiratory illness in young children. The radiologic characteristics of laboratory-confirmed HMPV acute respiratory illness in young children have not been systematically assessed. Objective We systematically evaluated the radiographic characteristics of acute respiratory illness associated with HMPV in a prospective cohort of pediatric patients. Materials and methods We included chest radiographs from children <5 years old with acute respiratory illness who were enrolled in the prospective New Vaccine Surveillance Network (NVSN) study from 2003 to 2009 and were diagnosed with HMPV by reverse transcription-polymerase chain reaction (RT-PCR). Of 215 HMPV-positive subjects enrolled at our tertiary care children’s hospital, 68 had chest radiographs obtained by the treating clinician that were available for review. Two fellowship-trained pediatric radiologists, independently and then in consensus, retrospectively evaluated these chest radiographs for their radiographic features. Results Parahilar opacities were the most commonly observed abnormality, occurring in 87% of children with HMPV. Hyperinflation also occurred frequently (69%). Atelectasis (40%) and consolidation (18%) appeared less frequently. Pleural effusion and pneumothorax were not seen on any radiographs. Conclusion The clinical presentations of HMPV include bronchiolitis, croup and pneumonia. Dominant chest radiographic abnormalities include parahilar opacities and hyperinflation, with occasional consolidation. Recognition of the imaging patterns seen with common viral illnesses like respiratory syncytial virus (RSV) and HMPV might facilitate diagnosis and limit unnecessary antibiotic treatment.

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