![Tram track sign. The tram track sign may be explained by the presence of thickened bronchial branches on radiographs (black arrowheads in a and b), which reproduce a “tram line” appearance clearly shown on c. In d, the same appearance could be also described in a CT of a patient with cystic fibrosis: the coronal CT image shows thickened bronchial branches (cylindrical bronchiectasis)

Chiarenza, A., Esposto Ultimo, L., Falsaperla, D. et al. Chest imaging using signs, symbols, and naturalistic images: a practical guide for radiologists and non-radiologists. Insights Imaging 10, 114 (2019). https://doi.org/10.1186/s13244-019-0789-4](attachment:64e2fe7c-a76a-4b95-9496-da9199712a25:image.png)

Tram track sign. The tram track sign may be explained by the presence of thickened bronchial branches on radiographs (black arrowheads in a and b), which reproduce a “tram line” appearance clearly shown on c. In d, the same appearance could be also described in a CT of a patient with cystic fibrosis: the coronal CT image shows thickened bronchial branches (cylindrical bronchiectasis)

Chiarenza, A., Esposto Ultimo, L., Falsaperla, D. et al. Chest imaging using signs, symbols, and naturalistic images: a practical guide for radiologists and non-radiologists. Insights Imaging 10, 114 (2019). https://doi.org/10.1186/s13244-019-0789-4