An 83-year-old man with the diagnosis of acute lymphatic leukaemia developed cardiac decompensation with oedema of the lower limbs. CT of the chest (Fig. 11) showed a patchy distribution of areas with ground-glass opacification. A superimposed linear pattern was also present. Most of the lines were thickened interlobular septa. Within the secondary pulmonary lobule, enlarged vascular structures with a spider configuration were seen. There were also some other intralobular lines. Fig. 11 Pulmonary oedema. CT showed patchy distribution of areas with ground-glass opacification and a linear pattern. Most of the lines were thickened interlobular septa. Within the secondary pulmonary lobule, enlarged vascular structures with a spider configuration were seen. There were also some other intralobular lines Fig. 12 Sarcoidosis. CT showed a diffuse increase in lung attenuation (ground-glass attenuation) with the superimposition of an irregular reticular pattern: thickening of the interstitium and thickening of the peribronchovascular interstitium