Figure 2b. Pseudo-ground-glass opacity at CT in a 66-year-old man. (a) Axial low-dose CT image (5-mm-thick section) obtained at the level of the left brachiocephalic vein shows a mixed ground-glass opacity lesion with a central solid component (arrow) in the upper lobe of the left lung, a finding suggestive of cancer. (b) Thin-section CT images show an irregularly shaped solid mass without nodular ground-glass opacity. (c) Coronal slab maximum intensity projection image shows a flat focus of atelectasis above the aortic arch (arrow) and no ground-glass opacity.