In radiology, the air crescent sign is a finding on chest X-ray and/or computed tomography that is crescenteric and radiolucent, due to a lung cavity that is filled with air and has a round radioopaque mass.[1] Classically, it is due to aspergilloma (a type of aspergillosis) in the lung. This occurs when Aspergillus colonizes a cavity in the lung.[2]
References
^ Abramson S. The air crescent sign. Radiology. 2001 Jan;218(1):230-2. PMID 11152807. Free Full Text.
^ Curtis AM, Smith GJ, Ravin CE. Air crescent sign of invasive aspergillosis. Radiology. 1979 Oct;133(1):17-21. PMID 472287. Free Full Text.