On thin-section CT images, six of 12 patients (50%) showed abnormal findings. Of these six patients, five (83%) had small GGOs; four patients had them in the upper lobe of the lung and one had a small GGO discovered in the lower lobe of the lung. Also, in four out of the five patients with small GGOs (80%), the lesions were localized in the periphery of the lung, and two of the five patients also showed bilateral involvement. For segmental involvement in terms of lesion size, three patients showed one segment, one patient showed two segments, one patient showed three segments, and one patient showed eight segments. Nodules were observed in all patients (100%), which were small in size with showing poorly defined margins (Fig. 2B) . In five patients (83%), the nodules were combined with GGOs in the same area. In addition, the nodule was a solitary finding in one patient (17%), which was located in the peripheral area of the right upper lobe. The patient who progressed into ARDS had bilateral lobar consolidations combined with GGOs, nodules, and bilateral pleural effusion (Fig. 3B) . One other patient showed right paratracheal lymphadenopathy. In our study, there was no evidence of calcification, mass, cavitation, or septal thickenings in any of the patients. The thin-section CT findings of the 12 patients are summarized in Table 3 .