Chest imaging using signs, symbols, and naturalistic images: a practical guide for radiologists and non-radiologists

Several imaging findings of thoracic diseases have been referred—on chest radiographs or CT scans—to signs, symbols, or naturalistic images. Most of these imaging findings include the air bronchogram sign, the air crescent sign, the arcade-like sign, the atoll sign, the cheerios sign, the crazy paving appearance, the comet-tail sign, the darkus bronchus sign, the doughnut sign, the pattern of eggshell calcifications, the feeding vessel sign, the finger-in-gloove sign, the galaxy sign, the ginkgo leaf sign, the Golden-S sign, the halo sign, the headcheese sign, the honeycombing appearance, the interface sign, the knuckle sign, the monod sign, the mosaic attenuation, the Oreo-cookie sign, the polo-mint sign, the presence of popcorn calcifications, the positive bronchus sign, the railway track appearance, the scimitar sign, the signet ring sign, the snowstorm sign, the sunburst sign, the tree-in-bud distribution, and the tram truck line appearance. These associations are very helpful for radiologists and non-radiologists and increase learning and assimilation of concepts. Therefore, the aim of this pictorial review is to highlight the main thoracic imaging findings that may be associated with signs, symbols, or naturalistic images: an “iconographic” glossary of terms used for thoracic imaging is reproduced—placing side by side radiological features and naturalistic figures, symbols, and schematic drawings.