Pitfalls in the diagnosis of pericardial effusion.

Echocardiography has proven to be a sensitive and reliable technique in the diagnosis of pericardial effusion. Care must be taken in recording to maintain proper angulation of the transducer, to scan adequate sites, and to maintain proper gain settings. The following entities may mimic pericardial effusion and must be excluded by careful analysis: left pleural effusion, mitral annulus calcification, anterior mediastinal space-occupying lesions, fibrinous pericardial reactions, and right heart catheters. Care must also be taken in the quantitation of pericardial fluid and in hemodynamic extrapolation.