Initial computed tomography findings of pneumonia in patients with human infected avian influenza (H7N9)

PurposeThe aim of this study was to assess initial computed tomography (CT) findings in patients diagnosed with H7N9 virus-associated pneumonia.Samples and methodsFrom March 2013 to July 2013, 14 hospitalized patients aged 47–81 years with a mean of 67.4 ± 9.7 years infected by avian influenza virus H7N9underwent chest CT scanning. The initial CT scans were obtained at d 7.6 ± 2.8 (range, 3–10days) after onset. The pattern, distribution, extent of the lesions, and their changes in follow-up CT scans were evaluated.ResultsAll patients presented a mixture of ground glass opacities and areas of consolidation on CT images. Air bronchogram was observed in 11 patients (78.6%). The coverage of the ground glass opacities was at least threefold larger than that of the consolidation in 7 patients (57.1%). The lesions were bilateral with multifocal distribution (n = 13); bilateral and diffuse (n = 1). The abnormalities had a predominantly subpleural and central distribution in 11 patients (78.6%) and a subpleural distribution in the other 3 patients (21.4%). Ten patients (71.4%) were found with pneumonic infiltration to the extent of ≥40%.Pleural effusion was found in 9 patients (64.3%). Follow-up CT scans in 10patients showed progress of the lesions in 8 patients, with a slow improvement thereafter.ConclusionPredominant ground glass opacities and less dominant consolidations, commonly along with air bronchogram, multifocal or bilateral involvement and a subpleural and central distribution, were initial CT findings of pneumonia in patients with avian influenza (H7N9). Extensive pneumonic infiltration and pleural effusion were common. The disease exhibited rapid progress of the lesions in the early stage of infection.