Oreo cookie sign (heart)

The Oreo cookie sign refers to the appearance of a pericardial effusion on lateral radiographs of the chest. A vertical opaque line (pericardial fluid) separating a vertical lucent line directly behind the sternum (paracardial fat) anteriorly from a similar lucent vertical lucent line (epicardial fat) posteriorly. It is now more often and better observed on CT.

It should not be confused with the double Oreo cookie sign of SLAP tears .