Lee Yu-Jin, Han Daehee, Koh Young Hwan, Zo Joo Hee, Kim Sang-Hyun, Kim Deog Kyeom, Lee Jeong Sang, Moon Hyeon Jong, Kim Jong Seung, Chun Eun Ju, Youn Byung Jae, Lee Chang Hyun, Kim Sam Soo
Department of Radiology, Cheil General Hospital, Kwandong University College of Medicine, Seoul, Korea.
Acta Radiol. 2008 Feb;49(1):37-40. doi: 10.1080/02841850701675677.
The sail sign is a well-known radiographic feature of the pediatric chest. This sign can be observed in an adult population as well, but for a different reason.
To investigate the sail sign appearing in adult chest radiography.
Based on two anecdotal adult cases in which frontal chest radiographs showed the sail sign, we prospectively screened radiographs of 10,238 patients to determine the incidence of the sail sign found in adults in their 40s or older. The cause of the sail sign was assessed using computed tomography (CT).
The sail sign was revealed in 10 (seven males, three females; median age 60.6 years) of 10,238 patients. Of these 10 patients with a sail sign on frontal radiographs, eight underwent CT. The frontal radiographs of these 10 patients showed a concave superior margin toward the lung in nine patients, a concave inferior margin in five, and a double-lined inferior margin in three. Lateral radiographs disclosed a focal opacity over the minor fissure in five of six patients, which was either fuzzy (n = 4) or sharp (n = 1) in its upper margin, and was sometimes double lined in the inferior margin (n = 3). CT revealed the anterior mediastinal fat to be the cause of the radiographic sail sign, which stretched laterally from the mediastinum to insinuate into the minor fissure.
The incidence of sail sign on adult chest radiographs is about 0.1%. The sign is specific enough to eliminate the need for more sophisticated imaging.
