title: Adult sail sign: radiographic and computed tomographic features.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  To investigate the sail sign appearing in adult chest radiography.
  
  
  METHODS
  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).
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Radiology, Cheil General Hospital, Kwandong University College of Medicine, Seoul, Korea.
authors.forename: Yu-Jin
authors.initials: YJ
authors.lastname: Lee
authors.forename: Daehee
authors.initials: D
authors.lastname: Han
authors.forename: Young Hwan
authors.initials: YH
authors.lastname: Koh
authors.forename: Joo Hee
authors.initials: JH
authors.lastname: Zo
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Deog Kyeom
authors.initials: DK
authors.lastname: Kim
authors.forename: Jeong Sang
authors.initials: JS
authors.lastname: Lee
authors.forename: Hyeon Jong
authors.initials: HJ
authors.lastname: Moon
authors.forename: Jong Seung
authors.initials: JS
authors.lastname: Kim
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Chun
authors.forename: Byung Jae
authors.initials: BJ
authors.lastname: Youn
authors.forename: Chang Hyun
authors.initials: CH
authors.lastname: Lee
authors.forename: Sam Soo
authors.initials: SS
authors.lastname: Kim
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008477:Mediastinal Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology; D008482:Mediastinum / Q000000981:diagnostic imaging; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D013902:Radiography, Thoracic / Q000379:methods*; D012680:Sensitivity and Specificity; D013950:Thymus Gland / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*