History: 50 year old male with shortness of breath and chest pain.

This is the classic “Oreo Cookie Sign” of pericardial effusion on the lateral chest radiograph. The most anterior radiolucent line (indicated by the red arrow) is the epicardial fat, the radiopaque line is the pericardial effusion, and the posterior radiolucent line (indicated by the yellow arrow) is the pericardial fat.

Typically pericardial effuions present with hest pain, pressure, or discomfort along with light-headedness, syncope, and possible palpitations. Pericardial effusions have numerous causes, of which the most common include:

1. Congestive heart failure

2. Post myocardial infarction (aka: “heart attack”), Dresslers syndrome

3. Chronic or end stage renal disease (uremic pericarditis)

4. Connective tissue disorders such as systemic lupus erythmatosus, rheumatoid arthritis

5. Drugs such as procainamide or hydralazine

6. Trauma or aortic dissection

Now go have some milk and cookies and reward yourself for learning something new today.