Fig. 28From: Chest imaging using signs, symbols, and naturalistic images: a practical guide for radiologists and non-radiologistsRailway track sign. The coronal CT image well depicts linear and centric filling defect (white arrow) inside the lumen of an arterial lung vessel—due to acute embolism; the contrast, surrounding the central endoluminal defect of opacification, reproduces a railway track appearance. The railway track sign is very similar to the polo mint sign, which instead describes the thrombosed vessel displayed according to an axial planeBack to article page