Figure 1.

Features suggestive of chronic hypersensitivity pneumonitis in different patients. (A) Spared pulmonary lobules are visible within non-fibrotic lung bilaterally (arrows); background fibrosis is evidenced by peripheral reticulation and traction bronchiectasis (black arrowheads). (B,C) A predilection towards bronchocentricity of the fibrosis in the upper lobes is evident on axial (arrowheads) and coronal (arrows) images. (D) An upper and midzone predominance to the fibrosis, characterised by reticulation and traction bronchiectasis, is seen on a coronal CT. Incidentally, volume loss in the right lung is noticeable by slight tenting and elevation of the right hemidiaphragm (arrow). (E) A UIP pattern with honeycomb cysts is visible in the left midzone of the lung (arrowhead) in a 74-year-old male ex-smoker. A surgical biopsy performed a few years before this CT had demonstrated findings compatible with fibrotic hypersensitivity pneumonitis.