Objective  To investigate the chest CT and radiographic manifestations of pneumonia due to novel swine-origin influenza A (H1N1) virus (S-OIV) infection.    Methods  Chest CT data and radiograms of 15 cases patients (including 5 cases of severe and 1 case of very severe) with novel S-OIV (H1N1) infection who admitted in our 2 hospitals during the November to December of 2009 were analyzed retrospectively. Imaging features

locations

numbers and evolutions of the lesions were studied.    Results  The chest findings showed that there were lung consolidation in 13 cases

ground-glass opacity (GGO) in 9 cases

air broncho grams in 6 cases

pleural effusions in 4 cases

pleural thickening in 3 cases

and multiple small lymphnodes in the mediastinum. There was no significant difference about these signs between less severe group and severe and very severe group (P0.05). There were 10 cases with lesions of lung consolidation and GGO in upper and lower lobes bilateral lungs and 5 cases with the lesions in one lobe of one lung. There was significant difference between two groups (P0.05). The lesions of lung consolidation and GGO in the chest were absorbed or reduced in 11 cases

no change was found in 2 cases

but the condition became more serious in 2 cases after therapy. There was no significant difference of these results between 2 groups (P0.05).    Conclusion  Chest CT and radiographic manifestations of novel S-OIV infection are mainly lung consolidation and GGO

with pleural

lymphnodes and other multiple abnormalities.