Pneumopericardium

Etiology: barotrauma
Imaging: air in pericardial space which does not rise above great vessels, continuous diaphragm sign, subset of pneumomediastinum
Clinical: can cause compromise of venous return -> cardiac tamponade -> death

Cases of Pneumopericardium

CXR of esophageal perforation from nasogastric tube placement — CXR AP shows air outlining the heart in the pericardial space, air outlining the thymus in the mediastinum, and air in the bilateral pleural spaces.

CXR of pneumopericardium — CXR AP (above) shows a large amount of air around the heart. CXR AP obtained after pericardiocentesis (below) shows a decreased amount of air around the heart and the diaphragm can be continuously traced across the image.