Chest radiography and computed tomography findings of cases with pandemic influenza A (H1N1/09) infection

Aim: To review the radiological findings of the chests of swine flu patients whose infections were confirmed clinically and/or by laboratory tests. Materials and methods: This study was conducted in the radiology and infectious diseases departments of a tertiarycare hospital, Ankara Training and Research Hospital, Ankara, Turkey. The X-ray and thorax computed tomography(CT) findings of swine flu patients were evaluated. Results: Included were 53 cases of swine flu. Thirty-eight of the patients (72%) underwent an initial chest X-ray and 17(32%) underwent thorax CT examinations. The mean age of the patients was 41 years; 23 (43%) patients were male and30 (57%) were female. In the chest X-rays, the most common pathology was patchy consolidations with a prevalence of 27%. Bilateral symmetrical involvement was observed in 42% of the cases. In the thorax CT, patchy consolidations (47%) and ground glass opacification (24%) were the most commonly observed patterns. Bilateral symmetrical involvement was observed in 41% of the cases. Pleural effusion was seen in 29% of the cases and mediastinal lymph adenopathy was observed in 41% of the cases. Conclusion: The most commonly observed radiological pattern of influenza A (H1N1) pulmonary infection is bilateral, symmetrical, patchy consolidations and/or ground glass opacities, predominantly located in middle-inferior zones with central peri bronchovascular distribution. Associated mediastinal lymph nodes, pleural effusion, and tree-in-bud patterns should raise the suspicion of superimposed infection.