Adult sail sign: radiographic and computed tomographic features.
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.
Lee
Yu-Jin
YJ
Department of Radiology, Cheil General Hospital, Kwandong University College of Medicine, Seoul, Korea.
Han
Daehee
D
Koh
Young Hwan
YH
Zo
Joo Hee
JH
Kim
Sang-Hyun
SH
Kim
Deog Kyeom
DK
Lee
Jeong Sang
JS
Moon
Hyeon Jong
HJ
Kim
Jong Seung
JS
Chun
Eun Ju
EJ
Youn
Byung Jae
BJ
Lee
Chang Hyun
CH
Kim
Sam Soo
SS
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*