Fig. 1.

Primary lung adenocarcinomas. Radiological features of pulmonary nodules according to their attenuation. (a) A low-dose CT thin-section shows a 15-mm non-solid nodule (pure ground-glass attenuation) of the right upper lobe: the nodule density is slightly higher than that of normal lung parenchyma, and vessels are visualized within the nodule (arrows). (b) Low-dose CT scan shows a 25-mm part-solid nodule of the right lower lobe. This nodule is characterized by a 3-mm central solid component (arrowhead) surrounded by a pure ground-glass opacity. The vessels and a small peripheral airway (arrow) can be clearly depicted within the ground-glass opacity. (c) Axial low-dose CT scan shows a 12-mm subpleural solid nodule of the left upper lobe. The spectrum of early stage lung cancer presentation at low-dose CT includes solid nodules as well as part-solid nodules and ground-glass nodules