Pneumonia induced by swine-origin influenza A (H1N1) infection: chest computed tomography findings in children

Yamada, Kentaro; Shinmoto, Hiroshi; Hamamoto, Manabu; Yoshida, Yusuke; Kawauchi, Toshio; Kaji, Tatsumi; Kosuda, Shigeru

PURPOSE: The purpose of this study was to determine the features of chest computed tomography (CT) in children with swine-origin influenza A (H1N1) virus (S-OIV). MATERIALS AND METHODS: The study population consisted of 16 children with laboratory-confirmed S-OIV infection (12 boys, 4 girls), with an age range of 5–10 years (mean 6.3 years). Pneumonia was suspected in these patients based on clinical features or confirmed by radiography. All subjects underwent CT for close evaluation of pneumonia, including characteristics, distribution, extent, and other findings such as pleural effusion, pneumothorax, and pneumomediastinum. RESULTS: The predominant CT finding was consolidation plus ground-grass opacity (GGO) (11/16, 69%). The consolidation-dominant pattern was found in 10 of 16 (66%) patients, and 1 (6%) was GGO-dominant. One (6%) had only GGO. In all, 7 of the 16 patients had segmental or lobar consolidation. Abnormal opacities were primarily distributed in the central lung zone (8/16, 50%) and were multifocal (15/16, 94%). Four showed atelectasis (4/16, 25%). Pneumomediastinum was observed in 4 of 16 (25%). One patient had negative radiographic findings but was positive on CT. CONCLUSION: Multifocal consolidation with central distribution is a common CT finding in children with S-OIV, but there are few GGO-dominant cases. Widespread consolidation (segmental or lobar) is also common.