Double density sign (left atrium)

Last revised by Dr Osamah A. A. Alwalid on 22 Dec 2020

The double-density sign, also known as the double right heart border, is seen on frontal chest radiographs in the presence of left atrial enlargement, and occurs when the right side of the left atrium extends behind the right cardiac shadow, indenting the adjacent lung and forming its own distinct silhouette 1-3

If large enough, the left atrium can actually reach beyond the border of the right atrium; this is known as atrial escape 3. The right superior pulmonary vein can lead to a similar appearance 1

See also

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Case 1
    Drag here to reorder.
  • Case 1: annotated
    Drag here to reorder.
  • Case 2
    Drag here to reorder.
  • Case 3: annotated
    Drag here to reorder.
  • Case 4
    Drag here to reorder.
  • Case 5
    Drag here to reorder.
  • Case 6
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.