Figure 4a:

CT findings of confirmed Coronavirus Disease 2019 (COVID-19) pneumonia Solitary rounded ground-glass opacity (GGO) pattern. A 51-year-old woman presenting without fever had close contact with patients with lab-confirmed COVID-19. a, Baseline axial unenhanced chest CT acquired 6 days before the first positive RT-PCR test showed a rounded GGO in the left lung upper lobe (arrow). b. Follow-up chest CT 4 days later showed the size increase of the lesion (arrow).