What are the imaging findings of a pericardial effusion?
Small pericardial effusions can be difficult to detect with chest radiography. The cardiac silhouette may show a globular “water bottle” configuration as the pericardial effusion increases. Pericardial effusion may lead to the “Oreo cookie” sign, which refers to an opaque band of fluid between the lucent pericardial fat and subpericardial fat on a lateral chest radiograph. Although the sign is specific, the sensitivity is limited. Hemorrhagic pericardial fluid or nodularity of the pericardium can be seen on CT or MRI, which are features more suggestive of a malignant effusion.