title: Focal obliteration of the descending aortic interface on normal frontal chest radiographs: correlation with CT findings.
abstract: OBJECTIVE
  To assess the frequency, location, correlation with age, and cause of partial obliteration of the descending aortic interface on normal frontal chest radiographs.
  
  
  METHODS
  Concurrent chest radiographs and computed tomographic (CT) scans of 1,500 patients in whom CT findings excluded a diagnosis of paraaortic pathologic processes were reviewed retrospectively.
  
  
  RESULTS
  Aortic interface obliteration was identified on 134 images (8.9%), which included 43 (2.9%) in the suprahilar and upper hilar portion, 56 (3.7%) in the lower hilar portion, and 46 (3.1%) in the cardiac portion of the interface. The causes were direct contact with or proximity to the aortic margin by pulmonary arteries at the suprahilar and upper hilar portion, superior segment vessels at the lower hilar portion, and various structures, including left inferior pulmonary vein, mediastinal fat, and left ventricle at the cardiac portion.
  
  
  CONCLUSIONS
  Partial aortic interface obliteration can be seen on normal frontal chest radiographs because of obstruction by small adjacent structures.
authors.affiliation: Department of Radiology, Jichi-Medical School Hospital, Tochigi-ken, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Shinozaki
authors.forename: H
authors.initials: H
authors.lastname: Hyodo
authors.forename: C
authors.initials: C
authors.lastname: Ogawa
authors.forename: T
authors.initials: T
authors.lastname: Ohsawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging*; D002648:Child; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging; D008297:Male; D008477:Mediastinal Diseases / Q000000981:diagnostic imaging; D008875:Middle Aged; D013902:Radiography, Thoracic; D012016:Reference Values; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed