- post myocardial infarction (Dressler syndrome)
- connective tissue disorders
- primary : e.g pericardial mesothelioma
Radiographic features in Plain film (CXR)* a very small pericardial effusion can be occult on plain film
* there can be globular enlargement of the cardiac shadow giving a "water bottle" configuration.
* lateral CXR may show an "Oreo Cookie Sign" : a vertical lucent line directly behind sternum (epicardial fat), behind this a vertical opaque line (pericardial fluid) and behind this a vertical lucent line (pericardial fat).
* widening of the subcarinal angle without other evidence of left atrial enlargement may be an indirect clue.