title: Novel influenza A (H1N1) virus infection in children: chest radiographic and CT evaluation.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the chest radiographic and CT findings of novel influenza A (H1N1) virus infection in children, the population that is more vulnerable to respiratory infection than adults.
  
  
  METHODS
  The study population comprised 410 children who were diagnosed with an H1N1 infection from August 24, 2009 to November 11, 2009 and underwent chest radiography at Dankook University Hospital in Korea. Six of these patients also underwent chest CT. The initial chest radiographs were classified as normal or abnormal. The abnormal chest radiographs and high resolution CT scans were assessed for the pattern and distribution of parenchymal lesions, and the presence of complications such as atelectasis, pleural effusion, and pneumomediastinum.
  
  
  RESULTS
  The initial chest radiograph was normal in 384 of 410 (94%) patients and abnormal in 26 of 410 (6%) patients. Parenchymal abnormalities seen on the initial chest radiographs included prominent peribronchial marking (25 of 26, 96%), consolidation (22 of 26, 85%), and ground-glass opacities without consolidation (2 of 26, 8%). The involvement was usually bilateral (19 of 26, 73%) with the lower lung zone predominance (22 of 26, 85%). Atelectasis was observed in 12 (46%) and pleural effusion in 11 (42%) patients. CT (n = 6) scans showed peribronchovascular interstitial thickening (n = 6), ground-glass opacities (n = 5), centrilobular nodules (n = 4), consolidation (n = 3), mediastinal lymph node enlargement (n = 5), pleural effusion (n = 3), and pneumomediastinum (n = 3).
  
  
  CONCLUSIONS
  Abnormal chest radiographs were uncommon in children with a swine-origin influenza A (H1N1) virus (S-OIV) infection. In children, H1N1 virus infection can be included in the differential diagnosis, when chest radiographs and CT scans show prominent peribronchial markings and ill-defined patchy consolidation with mediastinal lymph node enlargement, pleural effusion and pneumomediastinum.
authors.affiliation: Department of Diagnostic Radiology, Dankook University College of Medicine, Dankook University Hospital, Chungnam, Korea.
authors.forename: Min Jeong
authors.initials: MJ
authors.lastname: Choi
authors.forename: Young Seok
authors.initials: YS
authors.lastname: Lee
authors.forename: Jee Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Kun Song
authors.initials: KS
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000821:virology*; D011857:Radiographic Image Interpretation, Computer-Assisted; D013902:Radiography, Thoracic; D056910:Republic of Korea / Q000453:epidemiology; D014057:Tomography, X-Ray Computed