Tram Track Sign on Chest CT • Parallel, non-tapering airways, extending to the lung periphery. • DDx; Cylindrical or traction bronchiectasis, CF, ILD, necrotizing pna, ABPA Kartagener's syndrome https://doi.org/10.1016/j.chest.201 #Tram #Track #Sign #CT #Lung #Pulmonary #diagnosis #radiology #clinical