present histologically in all active smokers, is characterised by the accumulation of pigmented “smoker’s macrophages” in respiratory bronchioles and neighbouring alveoli, containing granular, yellow-brown cytoplasmic pigments
Mosaic attenuation pattern. CT scan through lower lobes shows the indirect sign of constrictive obliterative bronchiolitis, in this case the sequel to a severe viral lower respiratory tract infection. https://pubs.rsna.org/doi/full/10.1148/radiol.13120908Tree-in-bud pattern. CT scan through lower lobes shows the direct sign of exudative bronchiolitis in a 42-year-old man with a sino-bronchial sepsis syndrome. https://pubs.rsna.org/doi/full/10.1148/radiol.13120908
