For each of the 78 patients, the CT scan was evaluated for the following characteristics: (1) distribution: presence of peripheral or peribronchovascular; (2) density: presence of ground-glass opacities, mixed ground-glass opacities, or consolidation; (3) internal structures: presence of air bronchogram, interlobular septal thickening, cavitation; (4) number of lobes affected by ground-glass or consolidative opacities; (5) presence of fibrotic lesions; (6) presence of centrilobular nodules; (7) presence of a pleural effusion; (8) presence of thoracic lymphadenopathy (defined as lymph node size of ≥ 10 mm in short-axis dimension); and (9) presence of underlying lung disease such as tuberculosis, emphysema, or interstitial lung disease were noted. Ground-glass opacification was defined as hazy increased lung attenuation with preservation of bronchial and vascular margins and consolidation was defined as opacification with obscuration of margins of vessels and airway walls [14].