Pericardial fluid distribution: CT analysis.

Ultrasound and computed tomographic (CT) descriptions of pericardial effusion commonly indicate that fluid accumulates posteriorly within the pericardial sac before filling other areas. However, in a retrospective study of 68 cases of pericardial effusion identified on chest CT, most of the effusions were noted to be located solely or predominantly anterior to the right ventricle. Anatomic features of the pericardium and its fibrous attachments, and the physical principle of buoyancy account for this observation.