Comet tail sign (CT thorax) explained

The comet tail sign is a radiological finding seen in chest CT. It refers to a specific appearance resembling a comet's tail, characterised by a bright, streaky opacity due to the presence of a round atelectasis in chest CT.^[1]

Description

In case of a round atelectatic mass, the nearby bronchovascular bundle appears to be pulled into the mass, resembling the tail of a comet. The comet tail usually extends from a central point in the lung periphery towards the hilum. If intravenous contrast is injected, homogenous enhancement is seen.^[2]

Notes and References

1. Chiarenza . Alessandra . Esposto Ultimo . Luca . Falsaperla . Daniele . Travali . Mario . Foti . Pietro Valerio . Torrisi . Sebastiano Emanuele . Schisano . Matteo . Mauro . Letizia Antonella . Sambataro . Gianluca . Basile . Antonio . Vancheri . Carlo . Palmucci . Stefano . Chest imaging using signs, symbols, and naturalistic images: a practical guide for radiologists and non-radiologists . Insights into Imaging . 4 December 2019 . 10 . 1 . 114 . 15 November 2023.
2. Partap . Vince A. . The Comet Tail Sign 1 . Radiology . November 1999 . 213 . 2 . 553–554 . 10.1148/radiology.213.2.r99nv08553.